CN203339701U - Multi-target loss reduction device - Google Patents

Abstract

The utility model relates to a multi-target loss reduction device which comprises a converter which employs a three-phase three-wire topological structure of a left-series right-parallel type. A left series converter is in series connection to a system-side alternating-current circuit through a transformer, so as to improve voltage quality. A right parallel converter is connected to a load-side alternating circuit through a capacitor, so as to improve current quality. A direct-current link of a central part is connected with two voltage-type PWM converters which are respectively served as series/parallel capacitors, and the direct-current link is served as an energy-exchange medium. LC circuits, which are served as passive filters, are respectively disposed at two sides, so as to eliminate switching frequency harmonic waves outputted by the two voltage-type PWM converters. A controller generates corresponding PWM trigger pulses according to the voltage sampling and current sampling data of the system and load sides, so as to drive each switch tube in the series and parallel converters to be connected and disconnected, thereby enabling the multi-target loss reduction device to complete harmonic wave elimination and reactive power compensation.

Description

Damage device falls in multiple target

Technical field

The utility model relates to power supply matching net wire loss aspect, and particularly damage device falls in a kind of multiple target.

Background technology

In recent years, along with the sustainable growth of electrical network electricity sales amount, improve the reasonable rate level of line loss electric company is had to long-range economic benefit.Therefore, this just requires power supply enterprise to pay attention to saving energy and decreasing loss work, in the construction of electrical network and running, adopts the technological means of science to make operation of power networks more rationally in the situation that meet social power demands, reduce as far as possible electric energy loss.In becoming more meticulous the analytic process of reasonable rate, line loss found some system problems, such as signal problem, data sudden change problem ,Tai district supply sale of electricity side measuring equipment fault etc., these problems all can directly produce negative impact to the reasonable rate index of electric company's line loss.

In recent years, along with the increase of net capacity, electric network reactive-load is required also to grow with each passing day.Reactive power compensation is to keep the electrical network high-quality to move a kind of Main Means, is to utilize technical measures to reduce one of important measures of line loss.

Active Power Filter-APF (APF) can solve the dynamic current quality problems of load, Dynamic Voltage Regulator (DVR) can resolution system the dynamic voltage quality problem, if APF and DVR are combined, can form that simultaneously bucking voltage is fallen, skyrocketed, instantaneous voltage interrupts, three-phase imbalance compensation, current harmonics compensation and reactive power compensation etc., the pure sine wave that the proof load terminal voltage is standard class and constant frequency, guarantee that the grid side electric current is and the synchronous pure sine wave of line voltage.

Different with mounting means according to the installation site of quality of power supply compensating unit, the right also topological structure of mode of a kind of left string is wherein arranged.As shown in Figure 1, usually by a pair of series/parallel current transformer, formed, share a DC energy storage link.During work, parallel converters is connected to load side, is mainly used in compensation harmonic and reactive current, maintains two direct voltages between current transformer constant simultaneously; Series converter is connected to system side, has the tie point of maintaining voltage, bucking voltage flickering and asymmetric function.

The utility model content

The purpose of this utility model is to provide a kind ofly can carry out harmonic wave elimination, reactive power compensation and make the multiple target of voltage stabilization fall damage device, by being tested and the test run data analysis, and final the proposition improving the effective solution of the reasonable rate of line loss.

In order to achieve the above object, the technical solution of the utility model is to provide a kind of multiple target and falls damage device, comprising adopting the right also converter of the three-phase three-wire system topological structure of type of left string, further comprises:

Left side series connection part is voltage compensation unit, is provided with the series converter connected and composed by 6 switching tubes of three brachium pontis, and described series converter is connected in series on the alternating current circuit of system side by a transformer, to improve the quality of voltage problem;

Right side part in parallel is the current compensation unit, is provided with the parallel converters connected and composed by 6 switching tubes of three brachium pontis, and described parallel converters is connected to by inductance on the alternating current circuit of load side, to improve the current quality problem; Wherein, described series converter and shunt capacitor are all the voltage PWM converters be coupled to form by direct current capacitor;

Mid portion is DC bus, forms the DC link that connects two the described voltage PWM converters in left and right, as the medium of energy exchange;

Also be provided with respectively the lc circuit as passive filter in the left and right sides, in order to eliminate the switching frequency harmonic wave of two described voltage PWM converter outputs;

Described multiple target is fallen in damage device and is also comprised controller, described controller can be according to the electric current and voltage sampled data of system side and load side, produce corresponding PWM trigger impulse, to drive the turn-on and turn-off of each switching tube in described series converter and parallel converters, make described multiple target fall damage device and complete harmonic wave elimination and reactive power compensation.

Described multiple target is fallen damage device and further is provided with lower module:

Shaping circuit and phase-locked loop circuit, the voltage signal obtained by external sampling is processed backward described controller output zero cross signal, frequency-doubled signal by described shaping circuit, phase-locked loop circuit successively; Described controller can obtain the synchronous pulse signal of line voltage from a wherein phase voltage signal of electrical network, to control described multiple target, falls damage device acquisition 0 angle position accurately;

Signal conditioning circuit, the three-phase current signal that external sampling obtains, be sent to described controller after processing by described signal conditioning circuit.

Described controller, by the buffering driver module, is connected with parallel converters with described series converter, sends corresponding PWM trigger impulse;

Described controller, also by fault locking signal module, is connected with parallel converters with described series converter, falls damage device when described multiple target and operates in abnormal state lower time, and described controller sends locking pulse and carrys out the lockout switch pipe, and device is quit work.

Be provided with external interrupt service subprogram module in described controller, when voltage over zero being detected, realize phase locked looped function.

Be provided with timer interrupt service subroutine module in described controller, it is by reading voltage, current sampling data, and when the generation voltage on line side falls, according to consider the least energy algorithm of phase hit based on Instantaneous Power Theory, carry out series side SVPWM calculating, fuzzyyer based on FUZZY() control algolithm, the voltage vector algorithm that Hysteresis Current is followed the tracks of, the calculating of realization to series and parallel side compensation rate, thus corresponding PWM trigger impulse exported.

Be provided with DC voltage closed-loop control subroutine module in described controller, difference and rate of change thereof by calculation expectation DC capacitor burning voltage and actual DC voltage, calculate PI control and export and preserve, calculate the stable controlled quentity controlled variable needed of DC capacitor voltage.

Described controller is a kind of dsp controller.

Compared with prior art, damage device falls in multiple target described in the utility model, its advantage is: the operation mechanism based on to device and energy flow, to, analysis and research that current main flow topology is carried out, have been determined topological structure and the control algolithm of device described in the utility model.This device can complete harmonic wave control and dynamic no-power compensation function according to on-the-spot real time data, reaches the target that reduces line loss, has the characteristics such as fast response time, stable and reliable operation, plug drawer type be non-maintaining.Putting into operation of damage device falls in multiple target, can effectively reduce the loss of electrical network, improves the area power grid quality of voltage, has good economic benefit and social benefit.

The accompanying drawing explanation

Fig. 1 is the right also topological structure schematic diagram of formula of left string.

Fig. 2 is that multiple target described in the utility model is fallen in damage device, the left and right string data topological structure schematic diagram that main circuit adopts;

Fig. 2 a is the single-phase fundamental equivalent electric circuit of main circuit in the utility model;

Fig. 3 is the power conversion unit topology diagram of series converter and parallel converters in the utility model;

Fig. 4 is the topological structure schematic diagram of the utility model middle controller;

Fig. 5 is the electrical schematic diagram that damage device falls in multiple target described in the utility model;

Fig. 6 is the flow chart of main program module in controller of the present utility model;

Fig. 7 is the flow chart of controller peripheral interruption subroutine module of the present utility model

Fig. 8 is the flow chart of timer interrupt service subroutine module in controller of the present utility model;

Fig. 9 is the flow chart of DC voltage closed loop control module in controller of the present utility model;

Figure 10 is the least energy backoff algorithm schematic diagram based on Instantaneous Power Theory consideration phase hit related in Fig. 8;

Figure 11 is the simulation model that damage device falls in multiple target described in the utility model.

Embodiment

What the damage device employing fell in multiple target described in the utility model is the right also type topological structure of left string.In three-phase three-wire system topological structure as shown in Figure 2, be connected to common DC bus by two 3-phase power converters by DC capacitor and form.Left side series connection part is voltage compensation unit, is the inverter consisted of 6 switching tubes of three brachium pontis, by a transformer, is connected in series on alternating current circuit, for improving various quality of voltage problems; Right side part in parallel is the current compensation unit, is also to consist of 6 switching tubes of three brachium pontis, by inductance, is connected on alternating current circuit, for improving the current quality problem; Mid portion is DC bus, forms the DC link that connects left and right two voltage PWM converters, as the medium of energy exchange.In structure, the lc circuit at two ends forms passive filter, for eliminating the switching frequency harmonic wave of two current transformer outputs.

Multiple target described in the utility model is fallen in damage device, comprises that series/parallel current transformer, filter circuit, series side transformer, side in parallel connect inductance and DC capacitor etc.A kind of preferred system parameters is: power frequency 50Hz, and the phase voltage effective value is 220V; Bearing power is 30kW, and load phase current first-harmonic effective value is 50A, and power factor is 0.866; DC voltage is 700V; The switching tube frequency is 6.4K.

For series converter and parallel converters, the Basic Topological of its power conversion unit is identical, as shown in Figure 3.In main circuit structure figure, series and parallel two parts main circuit structure all adopts the voltage-type current transformer of high frequency PWM technique, by direct current capacitor, is coupled to form.Describe in order to provide equivalent circuit, suppose that following condition meets the demands:

1) series converter can provide a balance, frequency and the fixing sinusoidal voltage of amplitude, be also that the load end harmonic voltage can be ignored.2) harmonic wave and the idle component of parallel converters in can the full remuneration load current, making source current is sinusoidal fundamental wave.3) switching frequency of voltage PWM converter is enough high, and the effect of low pass filter is enough to eliminate near the harmonic components of switching frequency that the converter switches action causes.4) the series side injection transformer is desirable.

Hypothesis based on above-mentioned, series converter and parallel converters can come equivalent with controlled current source and controlled voltage source respectively.Obtain single-phase fundamental equivalent electric circuit as shown in Figure 2 a with this, wherein

The complex power of power supply input is:

(1)

Wherein, power supply active power

, reactive power

.

The complex power of load-side is: (2)

Wherein, load active power , reactive power

.

If meet the loss-free assumed condition of device, the active power that power supply sends should equal the active power of load consumption, meets:

;

So have:

.(3)

Two groups of output filters are as the important component part of device, the high frequency burr caused while being mainly used to eliminate series converter and parallel converters work.Side in parallel connects inductance and had both made output interface, also as filter, uses.If switching frequency is 12.8kHz, thus consequent harmonic current will concentrate near 12.8 kHz, if undistorted recovery sampled signal, the actual harmonic number that can compensate is lower, select 31 subharmonic for the highest compensation number of times, it is 1550Hz by frequency for this reason, so according to:

; And, in conjunction with actual test effect, determine filter reactance and capacitance.

Also be provided with controller as shown in Figure 4 in the utility model.This controller can be a kind of dsp controller, for example adopts the TMS320F28335 type digital signal processor that TI company releases to form.The start and stop of described controller by obtaining online detection and administration module and signal acquisition module and transmit, protection, voltage, current signal etc. produce and control the pulse of current transformer device driving switch device, make equipment produce required electric current and idle.That is, the voltage signal obtained by sampling is processed backward this controller output zero cross signal, frequency-doubled signal by shaping circuit, phase-locked loop circuit, and three-phase current signal Ia, Ib, Ic are sent to controller after processing by signal conditioning circuit.This controller also is connected with the series/parallel current transformer by buffering driver module, fault locking signal module.This controller also is connected with FLASH memory, CAN interface, 232 interfaces, Man Machine Interface etc.

That is, in the utility model, the effect of this controller is mainly: 1) produce and drive the IGBT pulse.Produce the PWM trigger impulse by result of calculation and control mode, go to control the turn-on and turn-off of IGBT in the series/parallel current transformer after gate drive circuit amplifies, make equipment complete the function of harmonic wave control and compensating power.2) obtain accurate and stable synchronized signal.Obtain the synchronous pulse signal of line voltage from a wherein phase voltage signal of electrical network, make equipment can obtain 0 angle position accurately.3) real-time communication function.Can received current and idle given, and produce given electric current and reactive power, and the transmission operating state.Comprise that current tracking provides the leading or hysteresis reactive current of regulation, control DC capacitor voltage to be stabilized in load voltage value.4) defencive function.When equipment operates under overvoltage, overcurrent, overload or other abnormal states, controller should send locking pulse and block IGBT, and equipment is quit work.

Describe in conjunction with the topological structure of Fig. 2 ~ Fig. 4 and correspondence above, provided the electrical schematic diagram that damage device falls in multiple target as shown in Figure 5.Described multiple target is fallen damage device and is comprised: the components and parts such as converter, dsp controller, load current detection transducer, microcomputer monitoring plate and 485 bus interface.The main circuit of converter finger device, comprise forming the IGBT of series/parallel current transformer and driving thereof, linked reactor, DC capacitor, closed assembly busbar and for installing offset current transducer and the direct current voltage sensor of control.Dsp controller mainly, according to load current sampling calculating offset current reference value, controls by control algolithm the output that main circuit is realized offset current, main circuit is carried out to various protections simultaneously.Microcomputer monitoring plate (not shown) major function is the running status of supervising device, and complete and inner DSP control unit and and the apparatus module monitoring unit between Communication Control.

In addition, adopt novel reliable control algolithm in device described in the utility model, by the sampling of the electric current and voltage to access dot system side and load side, obtain the running status of system, comprehensive judge and merges after must auto levelizer control target, realization is to the state-detection of load and the purpose of multi objective control, makes device have better overall compensation effect, dynamic responding speed, larger advantages such as expansion capacity faster.

Be provided with several following functional modules in described controller of the present utility model, carry out the control algolithms such as the detection of specific implementation compensation rate and compensation rate control:

Be provided with main program module in the utility model, mainly complete the interrupt vector of initialization and the assigned interrupt service of each several part.Its flow chart as shown in Figure 6, first carries out the initialization of the correlation modules such as system, variable, I/O, A/D, EV, and the definition interrupt vector, open total interruption; Waited for afterwards, until external interrupt XINT2 when request arranged, forwarded to corresponding XINT2 service subprogram.

Also be provided with external interrupt service subprogram module in the utility model, be mainly used in voltage over zero and detect, realize the function of phase-locked loop.Utilize the periodic signal circuit for generating, can realize entering the external interrupt subprogram when A phase supply voltage zero crossing, and think that this moment voltage phase angle is zero, start timer in this subprogram the inside simultaneously.Its flow chart as shown in Figure 7, sets to 0 A phase electric network voltage phase variable, and the counter of timer is clear 0, starts timer, opens interruption, interrupts returning.

Also be provided with timer interrupt service subroutine module in the utility model, main task is to calculate fast series and parallel side compensation rate, and exports respectively pwm pulse signal.Its flow chart as shown in Figure 8, at first read voltage, current sampling data, wherein, if, when the generation voltage on line side falls, will call the least energy arithmetic subroutine of considering phase hit based on Instantaneous Power Theory, carrying out series side SVPWM calculates and output signal, call afterwards FUZZY(fuzzy) the control algolithm subprogram, call the voltage vector arithmetic subroutine that Hysteresis Current is followed the tracks of, last restoring scene, open interruption, interrupt returning.If, when voltage on line side not occurring falling, will directly jump to the step of calling FUZZY control algolithm subprogram, and carry out according to this its follow-up corresponding flow process.

When fluctuation occurs supply voltage, device detects the difference between reference voltage and practical power voltage, injects one by series transformer and offsets with it with the contrary voltage of detection difference, take and keeps the sinusoidal voltage that load terminal voltage is standard; Equally for load end, device detects the harmonic wave contained in load current, idle composition, inject the electric current contrary with it by parallel converters, thereby guarantee that source current is standard sine wave, suppress the pollution of the distortion current of nonlinear load generation to electrical network.The compensation policy difference of series side adopted, the meritorious and idle component of its output will change.And harmonic wave, idle component and maintain the constant real component of direct voltage in side in parallel output compensating load electric current, it is worth substantially constant.

Therefore, during influences series side adopted least energy compensation herein, the energy flow feature of device.During the least energy compensation policy, from the viewpoint of series converter energy storage, by introducing the idle compensation that realizes, employing and supply voltage have the leading voltage of suitable phase place to inject can reduce meritorious exchange.It is by making the active power that current transformer provides minimize the meritorious maximization that realizes that power supply provides.For the mains fluctuations situation with phase hit, the least energy backoff algorithm based on Instantaneous Power Theory consideration phase hit that proposes to describe in above-mentioned timer interrupt service subroutine module in the utility model.Adopt Instantaneous Power Theory to try to achieve supply voltage initial phase and saltus step angle, and provide the definite compensation of the principle optimal corner of function minimum according to the device series side, determine object voltage function, and finally calculate the compensation rate of series side.Its schematic diagram as shown in figure 10, is summarized as follows.

1) voltage effective value and starting phase angle calculate;

From instantaneous reactive power theory, the three-phase voltage in the abc coordinate system can transform in the dq coordinate system, that is: by Synchronous Reference Frame Transform

(32)

After Synchronous Reference Frame Transform, the harmonious wave component of three phase network voltage negative phase-sequence is still alternating current component, by two low pass filters, fundamental positive sequence can be extracted respectively. with

corresponding amount in the dq space is a DC component, and the peak value of the drop-off voltage in numerical value and abc system , the fundamental voltage initial phase angle

and supply voltage phase hit angle

between exist following relation:

(33)

Can calculate

(34)

(35)

2) object voltage function is asked for;

Object voltage function is the voltage that load voltage reaches after the compensation of device series side.It is a trigonometric function, and amplitude is standard phase voltage amplitude, and this project is

v, phase angle is by the initial phase angle of fundamental voltage before mains fluctuations

, the load voltage phase hit angle that causes of fluctuation

and the least energy compensation policy is jointly determined.

In conjunction with the front energy flow, analyze:

When

the time,

can realize

minimum has: ;

When

the time,

can realize =0, i.e. least energy compensation has:

;

When

the time,

can realize

minimum.Have: ;

The bucking voltage that can obtain thus series side need provide meets:

(36)

In addition, in device described in the utility model, for the detection of current harmonics compensating instruction signal, by recursion discrete Fourier analytic approach or direct time-domain data analysis method, realize.The latter can also be further by 1) instantaneous reactive power theory of Akagi.H, 2) three-phase ABC system time domain data direct calculation method, 3) p-q compute mode in detection method based on vector, or compute mode realizes.

Also be provided with DC voltage closed-loop control subroutine module in the utility model.In theory, device described in the utility model does not exchange meritorious energy with electrical network, but in reality, due to element losses such as converter switches loss and capacitor and inductors, can make DC capacitor voltage mean value change, therefore must be in addition closed-loop control of DC capacitor voltage, to realize the stable of direct voltage.DC voltage closed loop control algorithm program flow diagram as shown in Figure 9, the difference of calculation expectation DC capacitor burning voltage and actual DC voltage , the rate of change of calculated difference

, preserve this difference

,

; Calculate the output of PI controller

, preserve this and control output variable

,

; Calculate the stable controlled quentity controlled variable needed of DC capacitor voltage

.

The optimization technique parameter of damage device falls in multiple target described in the utility model, is input voltage: the AC380V(three-phase three-wire system); Maximum reactive compensation capacity: 50Kvar; Power factor: > 0.99; Harmonic content:<5%; Response time :≤10ms.

In order to verify that damage device falls in this multiple target, the Software for Design based on TMS320F28335 carries out under the debugging enironment that SEED-TDS510USB2.0 simulator and the support of CCS3.1 code encoder are arranged.According to above-mentioned selected main circuit topology and control algolithm, set up simulation model as shown in figure 11, obtain simulation waveform as shown in figure 12, comprising: a) three-phase voltage source waveform, b) voltage harmonic, c) the bucking voltage waveform of inverter output, d) voltage waveform after the compensation, e) three-phase waveform, f) harmonic current waveform, g) the offset current waveform of inverter output, h) current waveform after the compensation.Visible, the utility model can effectively be realized harmonic wave elimination and reactive power compensation.

Claims (4)

1. damage device falls in a multiple target, it is characterized in that, the converter that damage device comprises the three-phase three-wire system topological structure that adopts the left string right side type falls in described multiple target, comprising:

Left side series connection part is voltage compensation unit, is provided with the series converter connected and composed by 6 switching tubes of three brachium pontis, and described series converter is connected in series on the alternating current circuit of system side by a transformer, to improve the quality of voltage problem;

Right side part in parallel is the current compensation unit, is provided with the parallel converters connected and composed by 6 switching tubes of three brachium pontis, and described parallel converters is connected to by inductance on the alternating current circuit of load side, to improve the current quality problem; Wherein, described series converter and shunt capacitor are all the voltage PWM converters be coupled to form by direct current capacitor;

Mid portion is DC bus, forms the DC link that connects two the described voltage PWM converters in left and right, as the medium of energy exchange;

Also be provided with respectively the lc circuit as passive filter in the left and right sides, to eliminate the switching frequency harmonic wave of two described voltage PWM converter outputs;

Described multiple target is fallen in damage device and is also comprised controller, described controller can be according to the electric current and voltage sampled data of system side and load side, produce corresponding PWM trigger impulse, to drive the turn-on and turn-off of each switching tube in described series converter and parallel converters, make described multiple target fall damage device and complete harmonic wave elimination and reactive power compensation.

2. damage device falls in multiple target as claimed in claim 1, it is characterized in that,

Described multiple target is fallen damage device and further is provided with lower module:

Shaping circuit and phase-locked loop circuit, the voltage signal obtained by external sampling is processed backward described controller output zero cross signal, frequency-doubled signal by described shaping circuit, phase-locked loop circuit successively, so that described controller can obtain the synchronous pulse signal of line voltage from a wherein phase voltage signal of electrical network, to control described multiple target, damage device acquisition 0 angle position accurately falls;

Signal conditioning circuit, the three-phase current signal that external sampling obtains, be sent to described controller after processing by described signal conditioning circuit.

3. damage device falls in multiple target as claimed in claim 2, it is characterized in that,

Described controller, by the buffering driver module, is connected with parallel converters with described series converter, sends corresponding PWM trigger impulse;

Described controller, also by fault locking signal module, is connected with parallel converters with described series converter, falls damage device when described multiple target and operates in abnormal state lower time, and described controller sends locking pulse and carrys out the lockout switch pipe, and device is quit work.

4. damage device falls in multiple target as claimed in claim 2 or claim 3, it is characterized in that,

Described controller is a kind of dsp controller.

Images