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CN104967100B - Voltage swells protective device, the method for pfc circuit in frequency-conversion domestic electric appliances equipment - Google Patents

Voltage swells protective device, the method for pfc circuit in frequency-conversion domestic electric appliances equipment Download PDF

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CN104967100B
CN104967100B CN201510288156.9A CN201510288156A CN104967100B CN 104967100 B CN104967100 B CN 104967100B CN 201510288156 A CN201510288156 A CN 201510288156A CN 104967100 B CN104967100 B CN 104967100B
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current
pfc
voltage
frequency
pfc circuit
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CN104967100A (en
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盛爽
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Midea Group Co Ltd
GD Midea Air Conditioning Equipment Co Ltd
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Midea Group Co Ltd
Guangdong Midea Refrigeration Equipment Co Ltd
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Abstract

The invention discloses a kind of voltage swells protective devices for pfc circuit in frequency-conversion domestic electric appliances equipment, including:First voltage detection module is used to detect the input voltage of pfc circuit;Current detection module is used to detect the input current of pfc circuit;Second voltage detection module is used to detect the output voltage of pfc circuit;Protection module generates the first comparison result, the second comparison result and third comparison result according to input voltage, input current and output voltage; and according to the first comparison result with the second comparison result respectively to pfc circuit carry out control and motor control, and according to third comparison result control frequency-conversion domestic electric appliances device powers down shut down.The protective device can ensure not shutting down operation when voltage swells and input current are less than the first current threshold.The invention also discloses a kind of voltage swells guard methods for pfc circuit in frequency-conversion domestic electric appliances equipment.

Description

Voltage swells protective device, the method for pfc circuit in frequency-conversion domestic electric appliances equipment
Technical field
The present invention relates to air-conditioning system technical fields, more particularly to a kind of for PFC (Power in frequency-conversion domestic electric appliances equipment Factor Correction, PFC) circuit voltage swells protective device and a kind of being used for frequency-conversion domestic electric appliances equipment The voltage swells guard method of middle pfc circuit.
Background technology
Frequency conversion is increasingly becoming the trend of household appliance, especially air-conditioning, refrigerator and washing machine etc., can by converter technique The electricity consumption of household appliance is greatly saved, and has many advantages, such as low noise and high-performance.
Since frequency conversion needs direct current supply, and general alternating current is the alternating current that voltage is fixed as 220V, and therefore, it is necessary to pass through Alternating current is changed into direct current with powering load by rectification circuit and booster circuit.In addition, in order to reduce household appliance operation The current harmonics and reactive power that generate in the process, generally use pfc circuit meet boost function and PFC work( Energy.
In frequency-conversion domestic electric appliances equipment, pfc circuit is usually Boost type pfc circuit, which includes mainly inductance, fast extensive Multiple diode and device for power switching, wherein device for power switching is the weight for realizing boost function and power factor emendation function Want device.And device for power switching be connected when electric current it is excessive or shutdown when voltage it is excessive, be all easy to cause power switch device Part damages, and therefore, it is necessary to be protected to it.
And there are many reason of causing device for power switching overvoltage or overcurrent, for example, the quality of power supply used is exactly it In an importance.When the voltage generation disturbance (supply voltage instantaneously falls or rises suddenly) of power supply used such as alternating current, or Person's software control algorithm is unreasonable or handling can all cause device for power switching that overcurrent or overvoltage occurs not in time (low-response), from And device for power switching is caused to damage.
In the related technology, load supplying is disconnected to protect device for power switching by directly opening defencive function.But This method is for end power grid or distributed power grid, such as small towns and rural power grids, since network voltage is unstable and disturbance is frequent, Household appliance is difficult normal table work, especially frequency-conversion domestic electric appliances equipment, it is easy to frequent start-stop is in the presence of, both not have The effect for saving electricity, also greatly affected comfort and the experience of user.
Invention content
The present invention is directed to solve at least some of the technical problems in related technologies.
For this purpose, an object of the present invention is to provide a kind of voltage swells for pfc circuit in frequency-conversion domestic electric appliances equipment Protective device can ensure not shutting down operation when voltage swells and input current are less than the first current threshold, and electric in input Power-off is shut down when stream is more than the first current threshold, avoids frequency-conversion domestic electric appliances equipment damage.
It is another object of the present invention to propose a kind of voltage swells protection for pfc circuit in frequency-conversion domestic electric appliances equipment Method.
In order to achieve the above objectives, one aspect of the present invention embodiment proposes a kind of for pfc circuit in frequency-conversion domestic electric appliances equipment Voltage swells protective device, the frequency-conversion domestic electric appliances equipment includes that the pfc circuit, the control pfc circuit open and close PFC control module, motor, electric machine controller, the voltage swells protective device includes:First voltage detection module, it is described First voltage detection module is used to detect the input voltage of the pfc circuit;Current detection module, the current detection module are used In the input current for detecting the pfc circuit;Second voltage detection module, the second voltage detection module are described for detecting The output voltage of pfc circuit;And protection module, the protection module respectively with the first voltage detection module, the electricity Stream detection module, the second voltage detection module, the PFC control module are connected with the electric machine controller, the protection Module is for being compared the input voltage and the output voltage to generate the first comparison result, and to input electricity Stream and preset maximum allowed current are compared to generate the second comparison result, and are more than the first electricity in the input current It flows protection module when threshold value and generates third comparison result, and the protection module is according to first comparison result and institute The second comparison result is stated to carry out control to the pfc circuit by the PFC control module respectively and control by the motor Device controls the motor, and passes through the master controller in the frequency-conversion domestic electric appliances equipment according to the third comparison result It controls the frequency-conversion domestic electric appliances device powers down to shut down, wherein first current threshold is more than the preset maximum allowed current.
Voltage swells protective device according to the ... of the embodiment of the present invention for pfc circuit in frequency-conversion domestic electric appliances equipment, the first electricity The input voltage of detection module detection pfc circuit, current detection module is pressed to detect the input current of pfc circuit, second voltage inspection The output voltage of module detection pfc circuit is surveyed, protection module is compared input voltage and output voltage to generate the first ratio Compared with as a result, and input current and preset maximum allowed current are compared to generate the second comparison result, and inputting Electric current be more than the first current threshold when protection module generate third comparison result, and protection module according to the first comparison result and Second comparison result carries out control to pfc circuit by PFC control module respectively and is controlled to motor by electric machine controller System, and shut down by the main controller controls frequency-conversion domestic electric appliances device powers down in frequency-conversion domestic electric appliances equipment according to third comparison result, To when voltage swells and input current are less than the first current threshold, effectively pfc circuit be avoided to damage, while ensureing motor not Operation is shut down, and power-off is shut down when input current is more than the first current threshold, is avoided frequency-conversion domestic electric appliances equipment damage, is effectively improved The reliability and user experience of frequency-conversion domestic electric appliances equipment.
According to one embodiment of present invention, when the input voltage is greater than or equal to the output voltage, wherein such as Input current described in fruit is greater than or equal to the preset maximum allowed current and is less than or equal to the second current threshold, the guarantor It protects module and exports the first protection signal to the PFC control module, so that the PFC control module controls the pfc circuit and closes It closes, and exports the first frequency reducing protection signal to the electric machine controller, so that the electric machine controller is by reducing rotary speed instruction To control the motor frequency reducing operation, wherein second current threshold is less than first current threshold and more than described pre- If maximum allowed current;If the input current is more than second current threshold and is less than or equal to first electric current Threshold value, the protection module export the first protection signal to the PFC control module, so that the PFC control module controls institute Pfc circuit closing is stated, and exports the second frequency reducing protection signal to the electric machine controller, so that the electric machine controller is by subtracting Low current instruction is run with controlling the motor frequency reducing.
According to one embodiment of present invention, when the input voltage is greater than or equal to the output voltage and the input When electric current is less than the preset maximum allowed current, the protection module exports the first protection signal to PFC control moulds Block so that the PFC control module closes the pfc circuit, and controls the motor according to pre- by the electric machine controller If frequency normal operation or the operation of frequency reducing in advance.
According to one embodiment of present invention, when the input voltage is less than the output voltage and the input current is big When the preset maximum allowed current, the protection module exports the first protection signal to PFC control moulds Block so that the PFC control module controls the pfc circuit and closes, and exports the first frequency reducing protection signal to the motor control Device processed, so that the electric machine controller is run by reducing rotary speed instruction with controlling the motor frequency reducing.
According to one embodiment of present invention, when the input voltage is less than the output voltage and the input current is small When the preset maximum allowed current, the PFC control module controls the pfc circuit and opens, the electric machine controller The motor is controlled according to predeterminated frequency normal operation.
In order to achieve the above objectives, another aspect of the present invention embodiment proposes a kind of for PFC electricity in frequency-conversion domestic electric appliances equipment The voltage swells guard method on road, the frequency-conversion domestic electric appliances equipment includes the pfc circuit, the control pfc circuit is opened and pass The PFC control module closed, motor, electric machine controller, the voltage swells guard method include the following steps:Detect the PFC The input voltage of circuit, and detect the input current of the pfc circuit;Detect the output voltage of the pfc circuit;To described defeated Enter voltage and the output voltage is compared to generate the first comparison result, and the input current and preset maximum are permitted Perhaps electric current is compared to generate the second comparison result, and generates third when the input current is more than the first current threshold Comparison result, wherein first current threshold is more than the preset maximum allowed current;And compare according to described first As a result respectively the pfc circuit control and by described by the PFC control module with second comparison result Electric machine controller controls the motor, and is passed through in the frequency-conversion domestic electric appliances equipment according to the third comparison result Frequency-conversion domestic electric appliances device powers down described in main controller controls is shut down.
Voltage swells guard method according to the ... of the embodiment of the present invention for pfc circuit in frequency-conversion domestic electric appliances equipment is examined first The input voltage of pfc circuit is surveyed, and detects the input current of pfc circuit and detects the output voltage of pfc circuit, then to defeated Enter voltage and output voltage be compared to generate the first comparison result, and to input current and preset maximum allowed current into Row is relatively to generate the second comparison result, and third comparison result is generated when input current is more than the first current threshold, most Controlled pfc circuit and passed through electricity by PFC control module respectively with the second comparison result according to the first comparison result afterwards Machine controller controls motor, and is become by the main controller controls in frequency-conversion domestic electric appliances equipment according to third comparison result The power-off of frequency household appliance is shut down, to when voltage swells and input current are less than the first current threshold, effectively avoid pfc circuit Damage, while ensureing that motor does not shut down operation, and when input current is more than the first current threshold, power-off is shut down, and avoids frequency conversion man Electric equipment is damaged, and the reliability and user experience of frequency-conversion domestic electric appliances equipment are effectively increased.
According to one embodiment of present invention, when the input voltage is greater than or equal to the output voltage, wherein such as Input current described in fruit is greater than or equal to the preset maximum allowed current and is less than or equal to the second current threshold, output the One protection signal so that the PFC control module controls the pfc circuit and closes, and exports first to the PFC control module Frequency reducing protection signal is to the electric machine controller, so that the electric machine controller is by reducing rotary speed instruction to control the motor Frequency reducing is run, wherein second current threshold is less than first current threshold and is more than the preset maximum allowable electricity Stream;If the input current is more than second current threshold and is less than or equal to first current threshold, output first Protection signal is to the PFC control module, so that the PFC control module controls the pfc circuit and closes, and exports the second drop Frequency protection signal is to the electric machine controller, so that the electric machine controller is dropped by reducing current-order with controlling the motor Frequency is run.
According to one embodiment of present invention, when the input voltage is greater than or equal to the output voltage and the input When electric current is less than the preset maximum allowed current, the first protection signal of output is to the PFC control module, so that described PFC control module closes the pfc circuit, and controls the motor by the electric machine controller and normally transported according to predeterminated frequency Row or the operation of frequency reducing in advance.
According to one embodiment of present invention, when the input voltage is less than the output voltage and the input current is big When the preset maximum allowed current, the first protection signal of output is to the PFC control module, so that described PFC control module controls the pfc circuit and closes, and exports the first frequency reducing protection signal to the electric machine controller, so that institute Electric machine controller is stated to run to control the motor frequency reducing by reducing rotary speed instruction.
According to one embodiment of present invention, when the input voltage is less than the output voltage and the input current is small When the preset maximum allowed current, the PFC control module controls the pfc circuit and opens, the electric machine controller The motor is controlled according to predeterminated frequency normal operation.
Description of the drawings
Fig. 1 is according to the embodiment of the present invention for the voltage swells protective device of pfc circuit in frequency-conversion domestic electric appliances equipment Block diagram;
Equivalent circuit diagram when Fig. 2 is the device for power switching IGBT conductings according to one embodiment of the present of invention;
Equivalent circuit diagram when Fig. 3 is the device for power switching IGBT shutdowns according to one embodiment of the present of invention;
Input when Fig. 4 input voltages according to an embodiment of the invention are less than output voltage in one switch periods The oscillogram of electric current;
Fig. 5 is the voltage and current waveform according to pfc circuit under the normal condition of one embodiment of the present of invention;
When Fig. 6 input voltages according to an embodiment of the invention are greater than or equal to output voltage in one switch periods Input current oscillogram;
The voltage current waveform of pfc circuit when Fig. 7 is the voltage swells according to the FPC circuits of one embodiment of the present of invention Figure;
It is protected when Fig. 8 is the voltage swells according to the FPC circuits of one embodiment of the present of invention and by voltage swells and is filled Set the voltage and current waveform of the pfc circuit after protection;And
Fig. 9 is according to the embodiment of the present invention for the voltage swells guard method of pfc circuit in frequency-conversion domestic electric appliances equipment Flow chart.
Specific implementation mode
The embodiment of the present invention is described below in detail, examples of the embodiments are shown in the accompanying drawings, wherein from beginning to end Same or similar label indicates same or similar element or element with the same or similar functions.Below with reference to attached The embodiment of figure description is exemplary, it is intended to for explaining the present invention, and is not considered as limiting the invention.
The electricity for pfc circuit in frequency-conversion domestic electric appliances equipment to describe to propose according to embodiments of the present invention with reference to the accompanying drawings Press rise sharply protective device and the voltage swells guard method for pfc circuit in frequency-conversion domestic electric appliances equipment.
Fig. 1 is according to the embodiment of the present invention for the voltage swells protective device of pfc circuit in frequency-conversion domestic electric appliances equipment Block diagram, wherein frequency-conversion domestic electric appliances equipment include pfc circuit, control pfc circuit open and close PFC control module 10, Motor M, electric machine controller 20.As shown in Figure 1, this is used for the voltage swells protective device packet of pfc circuit in frequency-conversion domestic electric appliances equipment Include first voltage detection module 30, current detection module 40, second voltage detection module 50 and protection module 60.
Wherein, first voltage detection module 30 is used to detect the input voltage of pfc circuit.Current detection module 40 is for examining Survey the input current of pfc circuit.Second voltage detection module 50 is used to detect the output voltage of pfc circuit.Protection module 60 is divided Not with first voltage detection module 30, current detection module 40, second voltage detection module 50, PFC control module 10 and motor Controller 20 is connected, and protection module 60 is used to be compared input voltage and output voltage to generate the first comparison result, and Input current and preset maximum allowed current are compared to generate the second comparison result, and are more than the in input current Protection module 60 generates third comparison result when one current threshold, and protection module 60 compares with second according to the first comparison result Relatively result carries out control to pfc circuit by PFC control module 10 respectively and is controlled to motor M by electric machine controller 20 System, and master controller in frequency-conversion domestic electric appliances equipment (in figure not specifically illustrated) control frequency conversion man is passed through according to third comparison result Electric equipment power-off is shut down, wherein the first current threshold is more than preset maximum allowed current.
It should be noted that when frequency-conversion domestic electric appliances equipment is air conditioner, motor M is compressor.
In an embodiment of the present invention, the first current threshold and preset maximum allowed current can according to actual conditions into Rower is fixed.
According to an embodiment of the present invention, when input voltage is greater than or equal to output voltage, wherein if input current More than or equal to preset maximum allowed current and it is less than or equal to the second current threshold, the output of protection module 60 first protection letter Number to PFC control module 10, so that PFC control module 10 controls pfc circuit and closes, and the first frequency reducing protection signal is exported to electricity Machine controller 20, so that electric machine controller 20 controls motor M frequency reducings operation by reducing rotary speed instruction, wherein the second electric current Threshold value is less than the first current threshold and is more than preset maximum allowed current;If input current is more than the second current threshold and small In or be equal to the first current threshold, protection module 60 exports the first protection signal to PFC control module 10, so that PFC controls mould Block 10 controls pfc circuit and closes, and exports the second frequency reducing protection signal to electric machine controller 20, so that electric machine controller 20 passes through Reduce current-order to control motor M frequency reducings operation.
In an embodiment of the present invention, the second current threshold can be demarcated according to actual conditions.
According to an embodiment of the present invention, when input voltage is greater than or equal to output voltage and input current is less than preset When maximum allowed current, protection module 60 exports the first protection signal to PFC control module 10, so that PFC control module 10 is closed Pfc circuit is closed, and motor M is controlled by electric machine controller 20 and is run according to predeterminated frequency normal operation or frequency reducing in advance.
According to an embodiment of the present invention, when input voltage is less than output voltage and input current is more than or equal to preset When maximum allowed current, protection module 60 exports the first protection signal to PFC control module 10, so that PFC control module 10 is controlled Pfc circuit processed is closed, and exports the first frequency reducing protection signal to electric machine controller 20, so that electric machine controller 20 turns by reducing Speed instruction is to control motor M frequency reducings operation.
According to an embodiment of the present invention, when input voltage is less than output voltage and input current is less than preset maximum and permits Perhaps when electric current, PFC control module 10 controls pfc circuit and opens, and electric machine controller 20 controls motor M and normally transported according to predeterminated frequency Row.
It is understood that the opening and closing of pfc circuit refer to the unlatching of device for power switching such as IGBT in pfc circuit And closing.
Specifically, Boost type pfc circuit shown in FIG. 1 includes mainly inductance L, fast recovery diode D1, power switch device Part IGBT and electrolytic capacitor EC.The input voltage V that protection module 60 is detected according to first voltage detection module 30in, current detecting The input current I that module 40 detectsinAnd the output voltage V that second voltage detection module 50 detectsoutCarry out decision power switch device The on off state of part IGBT and the operating status of motor M.
When device for power switching IGBT is in the conduction state, equivalent circuit is as shown in Fig. 2, the voltage on inductance L is The input voltage V of the voltage that AC power exports after diode rectifier bridge rectification, i.e. first voltage detection module 30 detectionin。 Due to input voltage VinIt is always more than zero, therefore, the electric current for flowing through inductance L is gradually increasing, i.e., current detection module 40 detects Input current IinGradually increase;When device for power switching IGBT is off state, equivalent circuit is as shown in figure 3, inductance L On voltage be pfc circuit input voltage VinWith output voltage VoutDifference.Since Boost type pfc circuit only has boosting work( Can, therefore, under normal operating conditions, the input voltage V of pfc circuitinLess than output voltage Vout, the voltage reversal on inductance L, At this point, flowing through the electric current of inductance L will be gradually reduced, i.e., the input current I that current detection module 40 detectsinIt is gradually reduced.Therefore, In a switch periods of device for power switching IGBT, input current IinWaveform as shown in figure 4, working as device for power switching When IGBT is connected, input current IinThe rate of rise be tan α=Vin/L0;When device for power switching IGBT is turned off, input electricity Flow IinDescending slope be tan β=(Vout-Vin)/L0, wherein L0For the inductance value of inductance L.
When AC supply voltage is normal, by controlling the conducting of device for power switching IGBT and turning off so that input voltage VinWith input current IinSame-phase, while ensureing output voltage VoutMeet the service requirement of motor M, at this point, input voltage Vin、 Input current IinAnd output voltage VoutWaveform it is as shown in Figure 5.
And when AC supply voltage is flown up, input voltage VinIt can exceed that output voltage Vout, at this point, even if control Device for power switching IGBT shutdowns processed, but due to the voltage (V on inductance Lin-Vout) it is more than zero, the electric current for flowing through inductance L still can Continue to rise, as shown in Figure 6.In addition, due to the presence of electrolytic capacitor EC so that output voltage VoutIt can not rise immediately, this When, flow through the electric current meeting rapid increase of inductance L up to overcurrent, as shown in Figure 7.It should be noted that time interval shown in Fig. 7 t1-t2For input voltage VinMore than output voltage VoutTime interval, in the time interval, if device for power switching IGBT is in the conduction state, then input current IinThe rate of climb can be faster.
In order to solve to make the input voltage V of Boost type pfc circuit because AC supply voltage is flown upinMore than output electricity Press VoutCaused by flow through inductance L electric current there is over-current phenomenon avoidance, in an embodiment of the present invention, protection module 60 is according to The input voltage V that one voltage detection module 30 detects in real timein, input current I that current detection module 40 detects in real timeinAnd The output voltage V that second voltage detection module 50 detects in real timeoutProtection control is carried out to pfc circuit and motor M.
Specifically, input voltage V of the protection module 60 to detectioninWith output voltage VoutIt is compared, to export first Protection signal PFC_PRT_FLAG is to PFC control module 10, and PFC control module 10 is according to the first protection signal PFC_PRT_FLAG Device for power switching IGBT is controlled.Wherein, as input voltage VinMore than or equal to output voltage VoutWhen, power switch The protection of device IGBT is opened, and the first protection signal PFC_PRT_FLAG sets 1, and the power that PFC control module 10 exports at this time is opened The duty ratio for closing the drive signal of device IGBT is 0, and pfc circuit is closed;As input voltage VinLess than output voltage VoutWhen, work( The protection of rate switching device IGBT is closed, and the first protection signal PFC_PRT_FLAG is reset, and PFC control module 10 exports at this time The drive signal of device for power switching IGBT is controlled by PFC control module 10.Meanwhile in order to prevent because of input current IinIt is excessive and Lead to over-current phenomenon avoidance, protection module 60 is also to input current IinJudged, and exports the second protection signal MTR_PRT_ FLAG controls motor M according to the second protection signal MTR_PRT_FLAG to electric machine controller 20, electric machine controller 20.Its In, as input current IinMore than or equal to preset maximum allowed current ImaxWhen, it is negative to reduce by the rotating speed for reducing motor M It carries, so that input current IinReduce, ensures that motor M does not shut down operation;As input current IinIt is maximum allowable less than preset Electric current ImaxWhen, motor M restores rated speed, with original load running.
It should be noted that working as input current IinMore than or equal to preset maximum allowed current ImaxWhen, work(in order to prevent It is damaged when the IGBT conductings of rate switching device, no matter input voltage VinWhether output voltage V is more thanout, it is both needed to ensure that power is opened It closes device IGBT and is off state.
In an embodiment of the present invention, protection module 60 can be according to control logic shown in table 1 to pfc circuit and motor M is controlled, to ensure effectively reduce the input current I of pfc circuit when AC supply voltage is flown upin, to Ensure pfc circuit not overcurrent, while ensureing that motor M does not shut down operation.
Table 1
Table 1 is described in detail with reference to specific example.
(1)Vout> VinAnd Iin< Imax
The state is the normal operating conditions of Boost type pfc circuit.The boost function of Boost type pfc circuit to export Voltage VoutMore than input voltage Vin, also, the input current I under normal operating conditionsinLess than preset maximum allowed current ImaxSuch as the maximum allowed current of device for power switching IGBT, at this point, pfc circuit is normally-open, motor M according to predeterminated frequency just Often operation.
(2)Vout≤VinAnd Iin< Imax
When being flown up when AC supply voltage such as network voltage is unstable, due to the presence of electrolytic capacitor EC so that Output voltage VoutRising lag behind input voltage Vin, therefore, there is output voltage VoutLess than input voltage VinThe case where, The voltage on inductance L is positive at this time, also, no matter whether device for power switching IGBT turns off, and flows through the electric current of inductance L all by one It is straight to rise, but since the electric current for flowing through inductance L cannot mutate, when Boost type pfc circuit is by normal operating conditions When into overvoltage condition, input current IinLess than preset maximum allowed current Imax
Assuming that device for power switching IGBT is in the conduction state, then in a switch periods of device for power switching IGBT Electric current ascending amount meet following formula (1):
Wherein, f is switching frequency, and D is IGBT conducting dutycycles.
Since AC supply voltage is flown up, input voltage VinAmplitude | Vin| it is much larger than input voltage VinWith output Voltage VoutDifference amplitude | Vin-Vout|, therefore, input current IinRise quickly.In order to avoid input current IinRose Soon, it while protecting device for power switching IGBT without damage, needs switch-off power switching device IGBT in this state, at this time power Electric current ascending amount in a switch periods of switching device IGBT meets following formula (2):
From above-mentioned formula (1) and formula (2) as can be seen that when device for power switching IGBT is off state, input Electric current IinRise it is slow, at this time can by electric machine controller 20 control motor M shift to an earlier date frequency reducing operation or according to default frequency Rate normal operation.
Specifically, when the inductance value of inductance L it is smaller (as use high frequency pfc circuit when, the switching frequency of pfc circuit More than 20kHz) when, even if device for power switching IGBT is constantly in off state, input current IinThe rate of climb also can be very Soon.Moreover, when electrolytic capacitor EC is bigger, output voltage VoutThe rate of climb it is slow, it is possible in a very long time Output voltage VoutInput voltage V will be all less thanin, it needs to shift to an earlier date frequency reducing operation by the control of electric machine controller 20 motor M at this time, Avoid over-current phenomenon avoidance.
In addition to the conditions already mentioned, in order to avoid motor M frequency reducings operation (such as air conditioner refrigeration effect variation) influences user experience, electricity Machine controller 20 can control motor M normal operations according to predeterminated frequency.
(3)Vout≤VinAnd Iin≥Imax
If output voltage VoutIt does not rise to also more than input voltage Vin, and input current IinAlready exceed it is preset most It is big to allow electric current Imax, for example, when network voltage flies up 100V or more, and the inductance value of inductance L is smaller, electrolytic capacitor The capacitance of EC is again very big, which probably occurs.It needs PFC control module 10 to control pfc circuit at this time to close, and passes through Electric machine controller 20 control motor M frequency reducings operation, on the one hand ensure device for power switching IGBT be not damaged, on the other hand due to Therefore the conveyance capacity of the devices such as diode rectifier bridge and fast recovery diode D1 may be used also much larger than device for power switching IGBT Motor M is set to rerun a period of time in a manner of being run by frequency reducing.If input current IinIt continues to rise, then needs to disconnect confession Power supply is to protect frequency-conversion domestic electric appliances equipment.
(4)Vout> VinAnd Iin≥Imax
If output voltage VoutIt has risen to and is more than input voltage Vin, but input current IinDo not restore also to normal Value, then in order to protect device for power switching IGBT, need to ensure that device for power switching IGBT is constantly in off state.At this point, by In output voltage VoutMore than input voltage Vin, the voltage reversal on inductance L, therefore, the electric current for flowing through inductance L is gradually reduced, Electric current reduction amount in a switch periods of device for power switching IGBT meets following formula (3):
Meanwhile in order to make input current IinFast quick-recovery need to control motor M frequency reducings to normal value by electric machine controller 20 Operation.
The input voltage V of pfc circuit after protectionin, input current IinWith output voltage VoutWaveform such as Fig. 8 institutes Show.It is compared it is found that when AC supply voltage is flown up with Fig. 7, can effectively reduce input current IinWith power switch device The electric current of part IGBT, and ensure not shutting down operation.
Further, in order to protect the safety of the device in addition to device for power switching IGBT, device failure is prevented, is also needed Judge input current IinWhether the first current threshold I is more thanmax2.As input current IinMore than the first current threshold Imax2When, no Pipe input voltage VinWhether output voltage V is more thanout, will all pass through the main controller controls frequency-conversion domestic electric appliances in frequency-conversion domestic electric appliances equipment Device powers down is shut down.Wherein, the first current threshold Imax2According to the maximum allowable of diode rectifier bridge and fast recovery diode D1 Electric current is set, also, since the conveyance capacity of diode rectifier bridge and fast recovery diode D1 are much larger than power switch device Part IGBT, therefore, the first current threshold Imax2Maximum allowed current, that is, preset maximum more than device for power switching IGBT permits Perhaps electric current Imax.The control logic of protection module 60 is as shown in table 2.
Table 2
Work as Vout> VinAnd Iin< ImaxWhen, it is the normal operating conditions of Boost type pfc circuit, is controlled at this time by motor Device 20 controls motor M according to predeterminated frequency normal operation.
Work as Vout≤VinAnd Iin< ImaxWhen, pfc circuit is controlled by pfc circuit protection module 10 and is closed, and passes through motor Controller 20 controls motor M and is run according to predeterminated frequency normal operation or frequency reducing in advance.Wherein, when the inductance value of inductance L compares When small and electrolytic capacitor EC capacitance is bigger, motor M is controlled by electric machine controller 20 and shifts to an earlier date frequency reducing operation, otherwise, is passed through Electric machine controller 20 controls motor M according to predeterminated frequency normal operation.
Work as Vout> VinAnd Imax≤Iin< Imax2When, switch-off power switching device IGBT first is to protect it from being damaged. In addition, due to output voltage VoutMore than input voltage VinSo that the voltage reversal on inductance L, input current IinIt will be gradually reduced To normal value, electric machine controller 20 can be by reducing rotary speed instruction ω at this time*Motor M frequency reducings operation is controlled, so that input electricity Flow IinCan fast quick-recovery to normal value.
Work as Vout≤VinAnd Imax≤Iin< Imax2When, pass through the second current threshold Imax21To further determine that motor frequency reducing Control mode when operation.Work as Vout≤VinAnd Imax≤Iin< Imax21When, switch-off power switching device IGBT is to protect it from Damage, and the first frequency reducing protection signal is exported to electric machine controller 20, electric machine controller 20 is by reducing rotary speed instruction ω*Control Motor M frequency reducings are run;Work as Vout≤VinAnd Imax21≤Iin< Imax2When, switch-off power switching device IGBT is to protect it from first It is damaged, in addition, though input current IinAlso it is not up to the first current threshold Imax2, but already close to the first current threshold Imax2, also, therefore the response speed of current regulation loops, can export far faster than the response speed of rotational speed regulation loop Two frequency reducing protection signals are to electric machine controller 20, and electric machine controller 20 is by reducing current-order Iq *The electromagnetism for making motor M generate Torque quickly reduces, and achievees the purpose that quick frequency reducing.
Work as Iin≥Imax2When, no matter input voltage VinWhether output voltage V is more thanout, input current IinAlready exceed change The ability to bear of device in frequency household appliance, it is therefore necessary to which power-off is shut down.
In conclusion the voltage swells protection dress according to the ... of the embodiment of the present invention for pfc circuit in frequency-conversion domestic electric appliances equipment It sets, first voltage detection module detects the input voltage of pfc circuit, and current detection module detects the input current of pfc circuit, the Two voltage detection modules detect the output voltage of pfc circuit, and protection module is compared with life input voltage and output voltage It is compared at the first comparison result, and to input current and preset maximum allowed current to generate the second comparison result, with And protection module generates third comparison result when input current is more than the first current threshold, and protection module is according to the first ratio Control is carried out and by electric machine controller to electricity to pfc circuit by PFC control module respectively compared with result and the second comparison result Machine is controlled, and disconnected by the main controller controls frequency-conversion domestic electric appliances equipment in frequency-conversion domestic electric appliances equipment according to third comparison result Electricity is shut down, to when voltage swells and input current are less than the first current threshold, effectively pfc circuit be avoided to damage, and ensure Motor does not shut down operation, and power-off is shut down to ensure that frequency-conversion domestic electric appliances equipment is not damaged when input current is more than the first current threshold It is bad, improve the reliability and user experience of frequency-conversion domestic electric appliances equipment.
Fig. 9 is according to the embodiment of the present invention for the voltage swells guard method of pfc circuit in frequency-conversion domestic electric appliances equipment Flow chart, wherein frequency-conversion domestic electric appliances equipment include pfc circuit, control pfc circuit open and close PFC control module, motor, Electric machine controller.As shown in figure 9, the voltage swells guard method for being used for pfc circuit in frequency-conversion domestic electric appliances equipment includes following step Suddenly:
S1, detects the input voltage of pfc circuit, and detects the input current of pfc circuit.
S2 detects the output voltage of pfc circuit.
S3 is compared input voltage and output voltage to generate the first comparison result, and to input current and presets Maximum allowed current be compared to generate the second comparison result, and generated when input current is more than the first current threshold Third comparison result.Wherein, the first current threshold is more than preset maximum allowed current.
S4 according to the first comparison result respectively controls pfc circuit by PFC control module with the second comparison result Motor is controlled with by electric machine controller, and the main control in frequency-conversion domestic electric appliances equipment is passed through according to third comparison result Device controls frequency-conversion domestic electric appliances device powers down and shuts down.
It should be noted that when frequency-conversion domestic electric appliances equipment is air conditioner, motor is compressor.
According to one embodiment of present invention, when input voltage be greater than or equal to output voltage, if input current is more than Or equal to preset maximum allowed current and it is less than or equal to the second current threshold, the first protection signal of output to PFC controls mould Block so that PFC control module control pfc circuit is closed, and exports the first frequency reducing protection signal to electric machine controller, so that motor Controller by reduce rotary speed instruction with control motor frequency reducing operation, wherein the second current threshold be less than the first current threshold and More than preset maximum allowed current;If input current is more than the second current threshold and is less than or equal to the first current threshold, The first protection signal is exported to PFC control module, so that PFC control module control pfc circuit is closed, and the second frequency reducing is exported and protects Signal is protected to electric machine controller, so that electric machine controller controls motor frequency reducing operation by reducing current-order.
According to one embodiment of present invention, when input voltage is greater than or equal to output voltage and input current is less than default Maximum allowed current when, the first protection signal of output is to PFC control module so that PFC control module closes pfc circuit, and Motor is controlled by electric machine controller to run according to predeterminated frequency normal operation or frequency reducing in advance.
According to one embodiment of present invention, when input voltage is less than output voltage and input current is more than or equal to default Maximum allowed current when, the first protection signal of output is to PFC control module, so that PFC control module control pfc circuit closes It closes, and exports the first frequency reducing protection signal to electric machine controller, so that electric machine controller is by reducing rotary speed instruction to control electricity Machine frequency reducing is run.
According to one embodiment of present invention, when input voltage is less than output voltage and input current is less than preset maximum When allowing electric current, PFC control module controls pfc circuit and opens, and electric machine controller controls motor according to predeterminated frequency normal operation.
It is understood that the opening and closing of pfc circuit refer to the unlatching of device for power switching such as IGBT in pfc circuit And closing.
A specific example according to the present invention, as shown in Figure 1, Boost type pfc circuit includes mainly inductance L, fast recovery Diode D1, device for power switching IGBT and electrolytic capacitor EC.In the circuit, electric resistance partial pressure method can be led to obtain respectively The input voltage V of pfc circuitinWith output voltage Vout, the input current I of pfc circuit is obtained by resistance sampling methodin, and According to the input voltage V of the pfc circuit of acquisitionin, input current IinWith output voltage VoutCarry out decision device for power switching IGBT On off state and motor operating status.
When device for power switching IGBT is in the conduction state, equivalent circuit is as shown in Fig. 2, the voltage on inductance L is The voltage that AC power exports after diode rectifier bridge rectification, i.e. input voltage Vin.Due to input voltage VinIt is always more than Zero, therefore, the electric current for flowing through inductance L is gradually increasing, i.e. input current IinGradually increase;It is closed when device for power switching IGBT is in When disconnected state, equivalent circuit is as shown in figure 3, the voltage on inductance L is the input voltage V of pfc circuitinWith output voltage Vout Difference.Since Boost type pfc circuit only has boost function, under normal operating conditions, the input voltage V of pfc circuitin Less than output voltage Vout, the voltage reversal on inductance L, at this point, flowing through the electric current of inductance L will be gradually reduced, i.e. input current Iin It is gradually reduced.Therefore, in a switch periods of device for power switching IGBT, input current IinWaveform as shown in figure 4, working as When device for power switching IGBT conductings, input current IinThe rate of rise be tan α=Vin/L0;When device for power switching IGBT is closed When disconnected, input current IinDescending slope be tan β=(Vout-Vin)/L0, wherein L0For the inductance value of inductance L.
When AC supply voltage is normal, by controlling the conducting of device for power switching IGBT and turning off so that input voltage VinWith input current IinSame-phase, while ensureing output voltage VoutMeet the service requirement of motor, at this point, input voltage Vin、 Input current IinAnd output voltage VoutWaveform it is as shown in Figure 5.
And when AC supply voltage is flown up, input voltage VinIt can exceed that output voltage Vout, at this point, even if control Device for power switching IGBT shutdowns processed, but due to the voltage (V on inductance Lin-Vout) it is more than zero, the electric current for flowing through inductance L still can Continue to rise, as shown in Figure 6.In addition, due to the presence of electrolytic capacitor EC so that output voltage VoutIt can not rise immediately, this When, flow through the electric current meeting rapid increase of inductance L up to overcurrent, as shown in Figure 7.It should be noted that time interval shown in Fig. 7 t1-t2For input voltage VinMore than output voltage VoutTime interval, in the time interval, if device for power switching IGBT is in the conduction state, then input current IinThe rate of climb can be faster.
In order to solve to make the input voltage V of Boost type pfc circuit because AC supply voltage is flown upinMore than output electricity Press VoutCaused by flow through inductance L electric current there is over-current phenomenon avoidance, it is in an embodiment of the present invention, defeated according to what is detected in real time Enter voltage Vin, input current IinAnd output voltage VoutProtection control is carried out to pfc circuit and motor.
Specifically, to the input voltage V of detectioninWith output voltage VoutIt is compared, to export the first protection signal PFC_PRT_FLAG is to PFC control module, and PFC control module is according to the first protection signal PFC_PRT_FLAG to power switch device Part IGBT is controlled.Wherein, as input voltage VinMore than or equal to output voltage VoutWhen, the guarantor of device for power switching IGBT Shield is opened, and the first protection signal PFC_PRT_FLAG sets 1, the drive of the device for power switching IGBT of PFC control module output at this time The duty ratio D of dynamic signal is 0, and pfc circuit is closed;As input voltage VinLess than output voltage VoutWhen, device for power switching IGBT Protection close, the first protection signal PFC_PRT_FLAG is reset, and the drive signal of device for power switching IGBT is controlled by PFC at this time Molding block controls.Meanwhile in order to prevent because of input current IinIt is excessive and lead to over-current phenomenon avoidance, also to input current IinInto Row judges that, to export the second protection signal MTR_PRT_FLAG to electric machine controller, electric machine controller is according to the second protection signal MTR_PRT_FLAG controls motor.Wherein, as input current IinMore than or equal to preset maximum allowed current Imax When, by reducing the rotating speed of motor to reduce load, so that input current IinReduce, ensures that motor does not shut down operation;When Input current IinLess than preset maximum allowed current ImaxWhen, motor restores rated speed, with original load running.
It should be noted that working as input current IinMore than or equal to preset maximum allowed current ImaxWhen, work(in order to prevent It is damaged when the IGBT conductings of rate switching device, no matter input voltage VinWhether output voltage V is more thanout, it is both needed to ensure that power is opened It closes device IGBT and is off state.
In an embodiment of the present invention, pfc circuit and motor are controlled according to control logic shown in above-mentioned table 1, To ensure effectively reduce the input current I of pfc circuit when AC supply voltage is flown upinWith flow through power switch device The electric current of part IGBT to ensure pfc circuit not overcurrent, and ensures that motor does not shut down operation.With reference to specific example to table 1 It is described in detail.
(1)Vout> VinAnd Iin< Imax
The state is the normal operating conditions of Boost type pfc circuit.The boost function of Boost type pfc circuit to export Voltage VoutMore than input voltage Vin, also, the input current I under normal operating conditionsinLess than preset maximum allowed current ImaxSuch as the maximum allowed current of device for power switching IGBT, at this point, pfc circuit is normally-open, motor is normal according to predeterminated frequency Operation.
(2)Vout≤VinAnd Iin< Imax
When being flown up when AC supply voltage such as network voltage is unstable, due to the presence of electrolytic capacitor EC so that Output voltage VoutRising lag behind input voltage Vin, therefore, there is output voltage VoutLess than input voltage VinThe case where, The voltage on inductance L is positive at this time, also, no matter whether device for power switching IGBT turns off, and flows through the electric current of inductance L all by one It is straight to rise, but since the electric current for flowing through inductance L cannot mutate, when Boost type pfc circuit is by normal operating conditions When into overvoltage condition, input current IinLess than preset maximum allowed current Imax
Assuming that device for power switching IGBT is in the conduction state, then in a switch periods of device for power switching IGBT Electric current ascending amount meet above-mentioned formula (1).Since AC supply voltage is flown up, input voltage VinAmplitude | Vin| it is remote More than input voltage VinWith output voltage VoutDifference amplitude | Vin-Vout|, therefore, input current IinRise quickly.In order to keep away Exempt from input current IinRise too fast, while protecting device for power switching IGBT without damage, need switch-off power to open in this state Device IGBT is closed, the electric current ascending amount in device for power switching IGBT a switch periods meets above-mentioned formula (2) at this time.
From above-mentioned formula (1) and formula (2) as can be seen that when device for power switching IGBT is off state, input Electric current IinRise it is slow, at this point it is possible to by electric machine controller control motor shift to an earlier date frequency reducing operation or according to predeterminated frequency Normal operation.
Specifically, when the inductance value of inductance L it is smaller (as use high frequency pfc circuit when, the switching frequency of pfc circuit More than 20kHz) when, even if device for power switching IGBT is constantly in off state, input current IinThe rate of climb also can be very Soon.Moreover, when electrolytic capacitor EC is bigger, output voltage VoutThe rate of climb it is slow, it is possible in a very long time Output voltage VoutInput voltage V will be all less thanin, need to shift to an earlier date frequency reducing operation by electric machine controller control motor at this time, avoid Over-current phenomenon avoidance occurs.
In addition to the conditions already mentioned, in order to avoid motor frequency reducing operation (such as air conditioner refrigeration effect variation) influences user experience, electricity Machine controller can control motor normal operation according to predeterminated frequency.
(3)Vout≤VinAnd Iin≥Imax
If output voltage VoutIt does not rise to also more than input voltage Vin, and input current IinAlready exceed it is preset most It is big to allow electric current Imax, for example, when network voltage flies up 100V or more, and the inductance value of inductance L is smaller, electrolytic capacitor The capacitance of EC is again very big, which probably occurs.It needs PFC control module control pfc circuit to close at this time, and passes through electricity Machine controller controls motor frequency reducing operation, on the one hand ensures that device for power switching IGBT is not damaged, on the other hand due to two poles The conveyance capacity of the devices such as pipe rectifier bridge and fast recovery diode D1 is much larger than device for power switching IGBT, and hence it is also possible to logical Crossing the mode of frequency reducing operation makes motor rerun a period of time.If input current IinIt continues to rise, then needs to disconnect power supply electricity Source is to protect frequency-conversion domestic electric appliances equipment.
(4)Vout> VinAnd Iin≥Imax
If output voltage VoutIt has risen to and is more than input voltage Vin, but input current IinDo not restore also to normal Value, then in order to protect device for power switching IGBT, need to ensure that device for power switching IGBT is constantly in off state.At this point, by In output voltage VoutMore than input voltage Vin, the voltage reversal on inductance L, therefore, the electric current for flowing through inductance L is gradually reduced, Electric current reduction amount in a switch periods of device for power switching IGBT meets above-mentioned formula (3).Meanwhile in order to keep input electric Flow IinFast quick-recovery need to control motor frequency reducing operation to normal value by electric machine controller.
The input voltage V of pfc circuit after protectionin, input current IinWith output voltage VoutWaveform such as Fig. 8 institutes Show.It is compared it is found that when AC supply voltage is flown up with Fig. 7, can effectively reduce input current IinAnd device for power switching The electric current of IGBT, and ensure not shutting down operation.
Further, in order to protect the safety of the device in addition to device for power switching IGBT, device failure is prevented, is also needed Judge input current IinWhether the first current threshold I is more thanmax2.As input current IinMore than the first current threshold Imax2When, no Pipe input voltage VinWhether output voltage V is more thanout, will all pass through the main controller controls frequency-conversion domestic electric appliances in frequency-conversion domestic electric appliances equipment Device powers down is shut down.Wherein, the first current threshold Imax2According to the maximum allowable of diode rectifier bridge and fast recovery diode D1 Electric current is set, also, since the conveyance capacity of diode rectifier bridge and fast recovery diode D1 are much larger than power switch device Part IGBT, therefore, the first current threshold Imax2Maximum allowed current, that is, preset maximum more than device for power switching IGBT permits Perhaps electric current Imax.Its control logic is as shown in Table 2 above.
Work as Vout> VinAnd Iin< ImaxWhen, it is the normal operating conditions of Boost type pfc circuit, is controlled at this time by motor Device controls motor according to predeterminated frequency normal operation.
Work as Vout≤VinAnd Iin< ImaxWhen, pfc circuit is controlled by pfc circuit protection module and is closed, and passes through motor control Device control motor processed is run according to predeterminated frequency normal operation or frequency reducing in advance.Wherein, when the inductance value of inductance L is smaller and electric When the capacitance of solution capacitance EC is bigger, motor is controlled by electric machine controller and shifts to an earlier date frequency reducing operation, otherwise, passes through electric machine controller Motor is controlled according to predeterminated frequency normal operation.
Work as Vout> VinAnd Imax≤Iin< Imax2When, switch-off power switching device IGBT first is to protect it from being damaged. In addition, due to output voltage VoutMore than input voltage VinSo that the voltage reversal on inductance L, input current IinIt will be gradually reduced To normal value, electric machine controller can be by reducing rotary speed instruction ω at this time*Motor frequency reducing operation is controlled, so that input current Iin Can fast quick-recovery to normal value.
Work as Vout≤VinAnd Imax≤Iin< Imax2When, pass through the second current threshold Imax21To further determine that motor frequency reducing Control mode when operation.Work as Vout≤VinAnd Imax≤Iin< Imax21When, switch-off power switching device IGBT is to protect it from Damage, and the first frequency reducing protection signal is exported to electric machine controller, electric machine controller is by reducing rotary speed instruction ω*Control motor Frequency reducing is run;Work as Vout≤VinAnd Imax21≤Iin< Imax2When, switch-off power switching device IGBT first is to protect it from being damaged It is bad, in addition, though input current IinAlso it is not up to the first current threshold Imax2, but already close to the first current threshold Imax2, and And therefore the response speed of current regulation loops, can export the second frequency reducing guarantor far faster than the response speed of rotational speed regulation loop Signal is protected to electric machine controller, electric machine controller is by reducing current-order Iq *The electromagnetic torque that motor generates is set quickly to reduce, Achieve the purpose that quick frequency reducing.
Work as Iin≥Imax2When, no matter input voltage VinWhether output voltage V is more thanout, input current IinAlready exceed change The ability to bear of device in frequency household appliance, it is therefore necessary to which power-off is shut down.
Voltage swells guard method according to the ... of the embodiment of the present invention for pfc circuit in frequency-conversion domestic electric appliances equipment is examined first The input voltage of pfc circuit is surveyed, and detects the input current of pfc circuit and detects the output voltage of pfc circuit, then to defeated Enter voltage and output voltage be compared to generate the first comparison result, and to input current and preset maximum allowed current into Row is relatively to generate the second comparison result, and third comparison result is generated when input current is more than the first current threshold, most Controlled pfc circuit and passed through electricity by PFC control module respectively with the second comparison result according to the first comparison result afterwards Machine controller controls motor, and is become by the main controller controls in frequency-conversion domestic electric appliances equipment according to third comparison result The power-off of frequency household appliance is shut down, to when voltage swells and input current are less than the first current threshold, effectively avoid pfc circuit Damage, while ensureing that motor does not shut down operation, and when input current is more than the first current threshold, power-off is shut down, and avoids frequency conversion man Electric equipment is damaged, and the reliability and user experience of frequency-conversion domestic electric appliances equipment are effectively increased.
In the description of the present invention, it is to be understood that, term "center", " longitudinal direction ", " transverse direction ", " length ", " width ", " thickness ", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom" "inner", "outside", " up time The orientation or positional relationship of the instructions such as needle ", " counterclockwise ", " axial direction ", " radial direction ", " circumferential direction " be orientation based on ... shown in the drawings or Position relationship is merely for convenience of description of the present invention and simplification of the description, and does not indicate or imply the indicated device or element must There must be specific orientation, with specific azimuth configuration and operation, therefore be not considered as limiting the invention.
In addition, term " first ", " second " are used for description purposes only, it is not understood to indicate or imply relative importance Or implicitly indicate the quantity of indicated technical characteristic.Define " first " as a result, the feature of " second " can be expressed or Implicitly include at least one this feature.In the description of the present invention, the meaning of " plurality " is at least two, such as two, three It is a etc., unless otherwise specifically defined.
In the present invention unless specifically defined or limited otherwise, term " installation ", " connected ", " connection ", " fixation " etc. Term shall be understood in a broad sense, for example, it may be being fixedly connected, may be a detachable connection, or integral;Can be that machinery connects It connects, can also be electrical connection;It can be directly connected, can also can be indirectly connected through an intermediary in two elements The interaction relationship of the connection in portion or two elements, unless otherwise restricted clearly.For those of ordinary skill in the art For, the specific meanings of the above terms in the present invention can be understood according to specific conditions.
In the present invention unless specifically defined or limited otherwise, fisrt feature can be with "above" or "below" second feature It is that the first and second features are in direct contact or the first and second features pass through intermediary mediate contact.Moreover, fisrt feature exists Second feature " on ", " top " and " above " but fisrt feature be directly above or diagonally above the second feature, or be merely representative of Fisrt feature level height is higher than second feature.Fisrt feature second feature " under ", " lower section " and " below " can be One feature is directly under or diagonally below the second feature, or is merely representative of fisrt feature level height and is less than second feature.
In the description of this specification, reference term " one embodiment ", " some embodiments ", " example ", " specifically show The description of example " or " some examples " etc. means specific features, structure, material or spy described in conjunction with this embodiment or example Point is included at least one embodiment or example of the invention.In the present specification, schematic expression of the above terms are not It must be directed to identical embodiment or example.Moreover, particular features, structures, materials, or characteristics described can be in office It can be combined in any suitable manner in one or more embodiments or example.In addition, without conflicting with each other, the skill of this field Art personnel can tie the feature of different embodiments or examples described in this specification and different embodiments or examples It closes and combines.
Although the embodiments of the present invention has been shown and described above, it is to be understood that above-described embodiment is example Property, it is not considered as limiting the invention, those skilled in the art within the scope of the invention can be to above-mentioned Embodiment is changed, changes, replacing and modification.

Claims (8)

1. a kind of voltage swells protective device for PFC pfc circuit in frequency-conversion domestic electric appliances equipment, which is characterized in that The frequency-conversion domestic electric appliances equipment include the pfc circuit, the control pfc circuit open and close PFC control module, motor, Electric machine controller, the voltage swells protective device include:
First voltage detection module, the first voltage detection module are used to detect the input voltage of the pfc circuit;
Current detection module, the current detection module are used to detect the input current of the pfc circuit;
Second voltage detection module, the second voltage detection module are used to detect the output voltage of the pfc circuit;And
Protection module, the protection module respectively with the first voltage detection module, the current detection module, described second Voltage detection module, the PFC control module are connected with the electric machine controller, and the protection module is used for input electricity Pressure and the output voltage are compared to generate the first comparison result, and to the input current and preset maximum allowable electricity Stream is compared to generate the second comparison result, and the protection module when the input current is more than the first current threshold Third comparison result is generated, and the protection module is led to respectively according to first comparison result and second comparison result The PFC control module is crossed to carry out control to the pfc circuit and control the motor by the electric machine controller, And frequency-conversion domestic electric appliances equipment described in the main controller controls in the frequency-conversion domestic electric appliances equipment is passed through according to the third comparison result Power-off is shut down, wherein first current threshold is more than the preset maximum allowed current;
Wherein, when the input voltage is less than the output voltage and the input current is less than the preset maximum allowable electricity When stream, the PFC control module controls the pfc circuit and opens, and the electric machine controller controls the motor according to default frequency Rate normal operation.
2. the voltage swells protection dress for PFC pfc circuit in frequency-conversion domestic electric appliances equipment as described in claim 1 It sets, which is characterized in that when the input voltage is greater than or equal to the output voltage, wherein
If the input current is greater than or equal to the preset maximum allowed current and is less than or equal to the second current threshold, The protection module exports the first protection signal to the PFC control module, so that the PFC control module controls the PFC Circuit is closed, and exports the first frequency reducing protection signal to the electric machine controller, so that the electric machine controller turns by reducing Speed instruction is run with controlling the motor frequency reducing, wherein second current threshold is less than first current threshold and is more than The preset maximum allowed current;
If the input current is more than second current threshold and is less than or equal to first current threshold, the protection Module exports the first protection signal to the PFC control module, so that the PFC control module controls the pfc circuit and closes, And the second frequency reducing protection signal is exported to the electric machine controller, so that the electric machine controller is by reducing current-order to control Make the motor frequency reducing operation.
3. the voltage swells protection dress for PFC pfc circuit in frequency-conversion domestic electric appliances equipment as described in claim 1 Set, which is characterized in that when the input voltage be greater than or equal to the output voltage and the input current be less than it is described default Maximum allowed current when, the protection module exports the first protection signal to the PFC control module, so that the PFC is controlled Molding block closes the pfc circuit, and by the electric machine controller control the motor according to predeterminated frequency normal operation or Frequency reducing in advance is run.
4. the voltage swells protection dress for PFC pfc circuit in frequency-conversion domestic electric appliances equipment as described in claim 1 Set, which is characterized in that when the input voltage be less than the output voltage and the input current be greater than or equal to it is described default Maximum allowed current when, the protection module exports the first protection signal to the PFC control module, so that the PFC is controlled Molding block controls the pfc circuit and closes, and exports the first frequency reducing protection signal to the electric machine controller, so that the motor Controller is run by reducing rotary speed instruction with controlling the motor frequency reducing.
5. a kind of voltage swells guard method for PFC pfc circuit in frequency-conversion domestic electric appliances equipment, which is characterized in that The frequency-conversion domestic electric appliances equipment include the pfc circuit, the control pfc circuit open and close PFC control module, motor, Electric machine controller, the voltage swells guard method include the following steps:
The input voltage of the pfc circuit is detected, and detects the input current of the pfc circuit;
Detect the output voltage of the pfc circuit;
The input voltage and the output voltage are compared to generate the first comparison result, and to the input current and Preset maximum allowed current is compared to generate the second comparison result, and is more than the first current threshold in the input current Third comparison result is generated when value, wherein first current threshold is more than the preset maximum allowed current;And
According to first comparison result and second comparison result respectively by the PFC control module to PFC electricity Road control and controlled the motor by the electric machine controller, and is passed through according to the third comparison result Frequency-conversion domestic electric appliances device powers down described in main controller controls in the frequency-conversion domestic electric appliances equipment is shut down, wherein when the input voltage When being less than the preset maximum allowed current less than the output voltage and the input current, the PFC control module control It makes the pfc circuit to open, the electric machine controller controls the motor according to predeterminated frequency normal operation.
6. the voltage swells protection side for PFC pfc circuit in frequency-conversion domestic electric appliances equipment as claimed in claim 5 Method, which is characterized in that when the input voltage is greater than or equal to the output voltage, wherein
If the input current is greater than or equal to the preset maximum allowed current and is less than or equal to the second current threshold, The first protection signal is exported to the PFC control module, so that the PFC control module controls the pfc circuit and closes, and it is defeated Go out the first frequency reducing protection signal to the electric machine controller, so that the electric machine controller is by reducing rotary speed instruction to control State motor frequency reducing operation, wherein second current threshold is less than first current threshold and is more than the preset maximum Allow electric current;
If the input current is more than second current threshold and is less than or equal to first current threshold, output first Protection signal is to the PFC control module, so that the PFC control module controls the pfc circuit and closes, and exports the second drop Frequency protection signal is to the electric machine controller, so that the electric machine controller is dropped by reducing current-order with controlling the motor Frequency is run.
7. the voltage swells protection side for PFC pfc circuit in frequency-conversion domestic electric appliances equipment as claimed in claim 5 Method, which is characterized in that when the input voltage be greater than or equal to the output voltage and the input current be less than it is described default Maximum allowed current when, the first protection signal of output is to the PFC control module, so that the PFC control module closes institute Pfc circuit is stated, and the motor is controlled by the electric machine controller and is run according to predeterminated frequency normal operation or frequency reducing in advance.
8. the voltage swells protection side for PFC pfc circuit in frequency-conversion domestic electric appliances equipment as claimed in claim 5 Method, which is characterized in that when the input voltage be less than the output voltage and the input current be greater than or equal to it is described default Maximum allowed current when, the first protection signal of output is to the PFC control module, so that the PFC control module controls institute Pfc circuit closing is stated, and exports the first frequency reducing protection signal to the electric machine controller, so that the electric machine controller is by subtracting Small rotary speed instruction is run with controlling the motor frequency reducing.
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