JP2002165482A - Motor controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a position-sensorless motor controller which can carry out control, taking into consideration the influence of an armature reaction against a phase induced voltage and a control effect delay against a power supply ripple to suppress speed fluctuation, noise, and vibration. SOLUTION: When a rotor position of a three-phase motor 3 is estimated, according to the phase induced voltage of the motor 3 detected by a phase voltage detecting means 5a, a control means 5 corrects the leading phase angle of the phase induced voltage caused by the influence of armature reaction, depending on the current of the three-phase motor 3 which is estimated according to the PWM signal pulse width, revolution, and a power supply voltage Vdc, in a current-sensorless manner for estimating the proper rotor position.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a motor control device capable of driving a three-phase motor at a variable speed from a single-phase AC power supply.

[0002]

2. Description of the Related Art A conventional motor control device will be described below. Conventional motor control devices of this type are disclosed in JP-A-10-15079 and JP-A-2000-8395.
There is a means disclosed in, for example, Japanese Patent No. 397.

First, the contents described in Japanese Patent Application Laid-Open No. 10-150795 will be described with reference to the drawings.
As shown in FIG. 4, a three-phase motor 3 is provided by a rectifier circuit 2 for full-wave rectifying the output of the single-phase AC power supply 1 and a variable voltage / variable frequency AC output obtained by switching the rectified output of the rectifier circuit 2. , A control unit 5 for controlling the inverter main circuit 4, and a position sensor 6 for providing information on the rotor position of the three-phase motor 3. PWM for turning on / off a switching element in the inverter main circuit 4 based on the
Signal generation means for generating a signal is provided.

In the above configuration, the control means 5 controls the pulse width of the PWM signal to increase or decrease so that a desired inverter output voltage can always be obtained by the signal generation means in response to the power supply ripple. In this case, when a saturation state occurs in which a desired inverter output cannot be obtained, the output timing of the PWM signal is advanced to advance the phase of the inverter output voltage, thereby making it possible to obtain a desired inverter output.

Next, the contents described in JP-A-2000-83397 will be described with reference to the drawings. As shown in FIG. 5, a three-phase motor 3 is provided by a rectifier circuit 2 for full-wave rectifying the output of the single-phase AC power supply 1 and a variable voltage / variable frequency AC output obtained by switching the rectified output of the rectifier circuit 2. And a control means 5 for controlling the inverter main circuit 4. The control means 5 detects a terminal voltage of the three-phase motor 3 during a dead time period of the switching element in the same phase. Voltage detection means 5a, phase current sign change detection means 5b for detecting the timing at which the sign of the phase current has changed from the terminal voltage detected by the phase voltage detection means 5a, and the phase current sign change timing and phase applied voltage. PWM based on the phase difference of
Switching element modulating means 5c for generating a signal.

In the above configuration, the sign of the phase current is detected by detecting the terminal voltage of the three-phase motor 3 during the dead time of the switching element by the phase voltage detecting means 5a, and the sign change of the phase current is detected. It is detected by the sign change detecting means 5b. The rotor position of the three-phase motor 3 is estimated from the detected phase current sign change timing, and the switching element modulator 5c controls the phase difference between the phase current sign change timing and the phase applied voltage.

Further, in the capacitor input type rectifier circuit 2 provided with a capacitor 7 having a sufficiently large capacity for smoothing and regenerative current, as shown in FIG. 6, an inrush current constituted by a resistor 8a and a relay 8b is provided. A prevention circuit 8 is provided. This is because the capacitor 7 is charged via the resistor 8a for a short time immediately after the power is turned on, and then a large charging current (rush current) flows when the power is turned on by turning on the relay 8b. This prevents the peripheral equipment from malfunctioning due to a momentary drop in the commercial power supply voltage.

[0008]

In such a conventional motor control device, the above-mentioned Japanese Patent Application Laid-Open No. 10-150795 is disclosed.
In the motor control device disclosed in Japanese Patent Application Laid-Open Publication No. H11-260, since the position sensor 6 detects the rotor position information of the three-phase motor 3 essential for driving the motor, the position sensor 6 is exposed to severe temperature and pressure conditions. It is not possible to realize driving in a closed state such as a compressor that is used. Further, when the conventional position sensorless driving means disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 2000-83397 is used, the field current weakening control in which the phase current increases for the output correction of the inverter main circuit 4 accompanying the reduction in the capacity of the capacitor 7 is performed. In the above-described motor control device, the influence of the leading phase angle of the phase induced voltage due to the armature reaction becomes large. Therefore, in the conventional technique of estimating the rotor position based on the phase induced voltage of the three-phase motor 3, the position detection is not performed. There was a problem that the error increased.

Further, the power supply ripple after rectifying the single-phase AC power supply 1 has a frequency twice as high as the power supply frequency.
It is necessary to correct the power supply ripple of 0 Hz or 120 Hz by controlling the increase and decrease of the pulse width of the PWM signal and the field weakening control. It takes a certain period before the effects of these corrections actually act on the driving of the motor. Therefore, in the above control method for performing these corrections in real time,
There is a problem that fluctuations in the rotation speed of the three-phase motor 3 to be driven, and vibration and noise accompanying the rotation speed cannot be sufficiently suppressed.

Further, when the capacity of the capacitor 7 connected between the output terminals of the rectifier circuit 2 is sufficiently large, an inrush current prevention circuit 8 is inserted to prevent an inrush current flowing to charge the capacitor 7 when the power is turned on. Need to
There is a problem that the number of parts increases.

The present invention solves the above-mentioned problems, and
By reducing or eliminating the capacity of the capacitor 7, the inrush current prevention circuit 8 becomes unnecessary, and further, in a method of estimating the rotor position based on the phase induced voltage of the three-phase motor 3, an electric motor depending on the motor current is used. Accurate rotor position estimation is performed by estimating the rotor position in consideration of the advancing phase angle of the phase induced voltage due to the child reaction, and the power supply ripple due to the reduction in the capacity of the capacitor 7 is predicted to obtain the PWM signal pulse width. An object of the present invention is to provide a motor control device which performs stable control by performing increase / decrease control and field weakening control to suppress fluctuations in rotation speed and accompanying vibration and noise.

[0012]

According to a first aspect of the present invention, there is provided a rectifier circuit for full-wave rectifying an output of a single-phase AC power supply, and a motor connected between output terminals of the rectifier circuit to be driven. A small-capacity capacitor for flowing a regenerative current, an inverter main circuit for driving the motor by an AC output of a variable voltage and a variable frequency obtained by switching a voltage applied to the capacitor, and controlling the overall operation. Control means for controlling a pulse width of a PWM signal for turning on and off a switching element in the inverter main circuit based on a voltage command value;
When the saturation of the inverter output voltage corresponding to the voltage command value cannot be obtained by the increase control of the pulse width of the M signal, a field weakening control that advances the output timing of the PWM signal to advance the phase of the inverter output voltage is performed. In the control to be performed, a motor control device is configured to perform position sensorless driving by estimating a rotor position based on a phase induced voltage in consideration of an armature reaction depending on a current amount of the motor.

According to the present invention, the estimated rotor position corrected for the effect of the armature reaction depending on the current amount of the motor
It can be driven stably without a position sensor.

According to a second aspect of the present invention, the amount of current of the motor is estimated from the voltage between the output terminals of the rectifier circuit, the pulse width of the PWM signal, and the number of revolutions of the motor, and the leading phase angle of the phase induced voltage due to the armature reaction. 3. The motor control device according to claim 1, wherein the motor current is corrected by the estimated current amount, and the rotor position is estimated based on the corrected phase induced voltage.

According to the present invention, the current amount of the motor can be estimated without using the current sensor and used for correcting the rotor position.

According to a third aspect of the present invention, there is provided a motor control device according to the first aspect, wherein the control for increasing / decreasing the pulse width of the PWM signal and the field weakening control are performed in consideration of a delay until the operation is applied to the motor drive. is there.

According to the present invention, when the capacitance of the capacitor connected to the rectifier circuit is reduced or eliminated, the effect of the power supply ripple accompanying the reduction can be accurately corrected and the drive can be stably performed.

According to a fourth aspect of the present invention, there is provided a configuration without an inrush current prevention circuit for protecting a peripheral device circuit from an inrush current flowing to charge a capacitor connected between output terminals of a rectifier circuit when power is turned on. The motor control device according to claim 1, wherein

According to the present invention, the overall configuration can be simplified.

[0020]

DETAILED DESCRIPTION OF THE INVENTION The present invention according to claim 1 is a rectifier circuit for full-wave rectifying the output of a single-phase AC power supply, and a regenerative motor connected between output terminals of the rectifier circuit and driven by a motor. A small-capacity capacitor for flowing a current, an inverter main circuit for driving the motor with a variable voltage / variable frequency AC output obtained by switching a voltage applied to the capacitor, and control for controlling the entire operation Means for controlling a pulse width of a PWM signal for turning on and off a switching element in the inverter main circuit based on a voltage command value, and increasing and decreasing a pulse width of the PWM signal. When a saturation state occurs where an inverter output voltage corresponding to the above is not obtained, the output timing of the PWM signal is advanced to advance the phase of the inverter output voltage. In the control to perform the field weakening control, the motor control apparatus that performs position-sensorless drive to estimate the rotor position based on the phase induced voltage in consideration of the armature reaction which depends on the current amount of the motor.

In the present invention, when estimating the rotor position from the phase induced voltage and the phase current sign change without a position sensor, the control means corrects the effect of the armature reaction depending on the current amount on the phase induced voltage. Then, the rotor position is estimated using the corrected phase induced voltage.

According to a second aspect of the present invention, the motor control device estimates the amount of current of the motor from the voltage between the output terminals of the rectifier circuit, the pulse width of the PWM signal, and the number of revolutions of the motor, and calculates the leading phase of the phase induced voltage due to the armature reaction. The motor control device according to claim 1, wherein the angle is corrected by the estimated current amount, and the rotor position is estimated based on the corrected phase induced voltage.

In the present invention, the control means estimates the amount of current of the motor from the voltage between the output terminals of the rectifier circuit, the pulse width of the PWM signal, and the number of revolutions of the motor, and uses the estimated amount of current to determine the motor of the phase induced voltage. The leading phase angle due to the child reaction is corrected, and the rotor position is estimated using the corrected phase induced voltage.

According to a third aspect of the present invention, the motor control device comprises a PW
The motor control device according to claim 1, wherein the control for increasing / decreasing the pulse width of the M signal and the field weakening control are performed in consideration of a delay until the signal acts on the motor drive.

In the present invention, the control means converts the A / D sampling data half a cycle before the cycle of the single-phase AC power supply of the power supply ripple accompanying the reduction in the capacity of the capacitor connected between the output terminals of the rectifier circuit. The control of increasing / decreasing the pulse width of the PWM signal and the field-weakening control are carried out. This eliminates the need for a high-performance microcomputer with a high A / D sampling rate and a high processing capacity required for performing real-time processing, and predicts power ripple from A / D sampling data half a cycle before. In other words, control is performed in consideration of a delay until the motor is actuated.

According to a fourth aspect of the present invention, the motor control device does not include an inrush current prevention circuit that protects a peripheral device circuit from an inrush current flowing to charge a capacitor connected between output terminals of the rectifier circuit when the power is turned on. A motor control device according to claim 1 having a configuration.

In the present invention, the motor control device has a structure in which the capacitance of the capacitor connected between the output terminals of the rectifier circuit is reduced or no capacitor is provided, thereby reducing or eliminating the rush current at the time of turning on the power. Eliminates the need for an inrush current prevention circuit.

Hereinafter, embodiments of the present invention will be described.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the motor control device according to the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of the present embodiment, FIG. 2 is a waveform diagram showing a leading phase angle of a phase induced voltage due to an armature reaction, and FIG. 3 shows a power supply ripple and a correction timing. It is a waveform diagram. The same components as those of the conventional example shown in FIG. 6 are denoted by the same reference numerals.

In the above configuration, first, the single-phase AC power supply 1
Is rectified by the rectifier circuit 2, a small-capacity capacitor 7 for flowing a regenerative current from the three-phase motor 3 to be driven is connected between output terminals of the rectifier circuit 2, and a voltage applied to the terminal of the capacitor 7 Is converted into a variable voltage / variable frequency AC output by the inverter main circuit 4 to drive the three-phase motor 3. The motor control device according to the present embodiment does not include a rush current prevention circuit for preventing malfunction of peripheral devices due to rush current when the power is turned on.

In the motor control device of the present embodiment, the phase control in consideration of the leading phase angle of the phase induced voltage due to the armature reaction is performed by the phase voltage detecting means 5a, the phase current sign change detecting means 5b, and the switching element modulating means 5c. The current value estimating means 5d performs the control of increasing / decreasing the pulse width of the PWM signal and the field-weakening control in consideration of a delay until the motor is driven.
And phase current sign change detecting means 5b and power supply frequency detecting means 5
e.

In the motor control, the timing at which the sign of the phase applied voltage command from the switching element modulating means 5c changes, and the sign of the phase current detected by the phase voltage detecting means 5a and the phase current sign change detecting means 5b are changed. The phase difference control for arbitrarily setting the phase difference with the changing timing is the same as that of the related art, and thus the detailed description is omitted here.

First, control in consideration of the leading phase angle of the phase induced voltage due to the armature reaction will be described. The phase induced voltage at the time of non-energization is as shown in FIG. But,
When the three-phase motor 3 is actually energized, the voltage as shown in FIG. 2C is superimposed due to the armature reaction, and the phase induced voltage becomes as shown in FIG. 2B. Here, for the sake of simplicity, the voltage generated by the armature reaction is shown as a rectangular wave. Thus, under the influence of the armature reaction, the zero cross point of the phase induced voltage is advanced as compared with the phase induced voltage when no current is supplied. Also, since the effect of this armature reaction depends on the motor current,
When the amount of current increases, the progress of the zero cross point of the phase induced voltage also increases as θ1 <θ2. Therefore, in the phase control of estimating the rotor position of the three-phase motor 3 from the phase current sign change point by the phase voltage detection means 5a and the phase current sign change detection means 5b, the rotor position information cannot be correctly detected.

Therefore, in order to consider the influence of the armature reaction based on the current amount, the phase control is performed by correcting the rotor position information obtained from the phase current sign change detecting means 5b. Here, the current value estimating means 5d estimates the amount of current for determining the magnitude of the effect of the armature reaction from the voltage Vdc between the output terminals of the rectifier circuit 2, the pulse width of the PWM signal, and the rotation speed of the three-phase motor 3. I do. As described above, the leading phase angle θ of the phase induced voltage is considered in consideration of the effect of the armature reaction depending on the current amount.
, It is possible to perform phase control that eliminates a position detection error due to the amount of current.

Next, a description will be given of how the control for increasing / decreasing the pulse width of the PWM signal and the field-weakening control are performed in consideration of a delay until the signal acts on the motor drive. These controls suppress fluctuations in the number of revolutions caused by power supply ripple caused by reducing the capacity of the capacitor 7 connected between the output terminals of the rectifier circuit 2 or eliminating the capacitor 7.

Here, the cycle of the power supply ripple is half of the cycle of the single-phase AC power supply 1, as shown in FIG. Therefore, if the half cycle of the single-phase AC power supply 1 is known in the period t1 shown in FIG. 3, the cycle of the power supply ripple to be corrected becomes clear. Further, during the period t1 in FIG.
D sampling is performed, and a period t
By performing the increase / decrease control of the pulse width and the field weakening control in 2, it is possible to perform the correction control in consideration of the delay of the timing of the pulse width increase / decrease control and the field weakening control and the timing of the action on the three-phase motor 3. in this way,
A / of the power supply ripple corresponding to a half cycle before the single-phase AC power supply 1
By performing power supply ripple correction based on the D sampling value, fluctuations in the rotational speed can be suppressed more reliably than when correction control is performed in real time.

The delay time may be a value measured in advance by a step response or the like.

Next, the reason why an inrush current prevention circuit for preventing malfunction of peripheral equipment from inrush current when the power is turned on is no longer necessary will be described. In the motor control device of the present embodiment, when the capacitance of the capacitor 7 connected between the output terminals of the rectifier circuit 2 is reduced or the capacitor 7 is unnecessary, the current for charging the capacitor 7 when the power is turned on becomes very small. Become. For this reason, even if the inrush current prevention circuit is not provided, it does not happen that the peripheral device malfunctions.

As described above, according to this embodiment, since a position sensor is not used, it is possible to realize driving under severe temperature and pressure conditions such as a compressor in a closed state.

Further, in a motor control device using field-weakening control for increasing the motor current for correcting the output of the inverter main circuit 4 due to the reduction in the capacity of the capacitor 7, the rotation taking into account the effect of the armature reaction depending on the motor current amount. By performing the child position detection, stable driving with no position detection error can be realized. At this time, the rotation speed of the three-phase motor 3
By estimating the motor current amount from the PWM signal pulse width and the voltage between the output terminals of the rectifier circuit 2, the position detection error can be corrected without using a current sensor. As for the A / D sampling data necessary for correcting the influence of the power supply ripple, the A / D sampling data half a cycle before each single-phase AC power supply cycle is used, so that the A / D sampling data is used.
The power ripple can be predicted and controlled without using a high-performance microcomputer having a high D sampling rate and a high processing capability.

Further, by reducing the capacity of the capacitor 7, the inrush current prevention circuit which has been required conventionally becomes unnecessary, and the number of parts can be reduced.

[0043]

According to a first aspect of the present invention, there is provided a rectifier circuit for full-wave rectifying an output of a single-phase AC power supply, and a regenerative current from a motor to be driven which is connected between output terminals of the rectifier circuit. A small-capacity capacitor for flowing, and a variable voltage obtained by switching the voltage applied to the capacitor.
An inverter main circuit that drives the motor with a variable frequency AC output; and a control unit that controls the entire operation, wherein the control unit turns on and off a switching element in the inverter main circuit based on a voltage command value. PWM
When the inverter becomes saturated so that an inverter output voltage corresponding to the voltage command value cannot be obtained by the pulse width increase / decrease control of the signal and the pulse width increase control of the PWM signal, the PWM is output.
In the control to perform the field weakening control to advance the phase of the inverter output voltage by advancing the output timing of the signal, the rotor position is estimated based on the phase induced voltage in consideration of the armature reaction depending on the current amount of the motor. By using a motor control device configured to perform position sensorless driving, the effect of the armature reaction depending on the motor current on the phase induced voltage is corrected, and the rotor position is estimated based on the corrected phase induced voltage, Stable driving can be realized while having a configuration without a position sensor.

According to a second aspect of the present invention, the amount of current of the motor is estimated from the voltage between the output terminals of the rectifier circuit, the pulse width of the PWM signal, and the number of revolutions of the motor, and the leading phase angle of the phase induced voltage due to the armature reaction. Is corrected by the estimated current amount, and the rotor position is estimated based on the corrected phase induced voltage, so that the motor current can be reduced without using a current sensor. The effect of the dependent armature reaction on the phase induced voltage can be corrected.

According to a third aspect of the present invention, there is provided a motor control apparatus according to the first aspect, wherein the control for increasing / decreasing the pulse width of the PWM signal and the field-weakening control are performed in consideration of a delay until the operation is applied to the motor drive. By doing so, it is possible to suppress fluctuations in rotation speed, vibration, and noise caused by power supply ripple due to reduction in the capacity of the capacitor connected between the output terminals of the rectifier circuit.

According to a fourth aspect of the present invention, there is provided the configuration according to the first aspect, wherein an inrush current preventing circuit for protecting a peripheral device circuit from an inrush current flowing to charge a capacitor of the rectifier circuit when the power is turned on is not provided. Since the motor control device eliminates the need for a rush current prevention circuit conventionally required, the overall configuration can be simplified and the number of components can be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of a motor control device of the present invention.

FIG. 2 is a waveform diagram showing a leading phase angle of a phase induced voltage due to an armature reaction.

FIG. 3 is a waveform chart showing power supply ripple and correction timing.

FIG. 4 is a block diagram showing a configuration of a conventional motor control device for performing power supply ripple correction control;

FIG. 5 is a block diagram illustrating a configuration of a conventional motor control device that performs position sensorless driving.

FIG. 6 is a circuit diagram showing a configuration of a rush current prevention circuit in a conventional example.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 single-phase AC power supply 2 rectifier circuit 3 three-phase motor (motor) 4 inverter main circuit 5 control means 5 a phase voltage detection means 5 b phase current sign change detection means 5 c switching element modulation means 5 d current value estimation means 5 e power supply frequency detection means 6 Position sensor 7 Capacitor 8 Inrush current prevention circuit 8a Resistance 8b Relay

Claims (4)

[Claims] A rectifier circuit for full-wave rectifying an output of a single-phase AC power supply; a small-capacitance capacitor connected between output terminals of the rectifier circuit for flowing regenerative current from a motor to be driven; An inverter main circuit that drives the motor with a variable voltage / variable frequency AC output obtained by switching the voltage applied to the capacitor, and control means for controlling the entire operation, the control means comprising: Pulse width increase / decrease control of a PWM signal for turning on / off a switching element in the inverter main circuit based on a command value;
Field weakening control for advancing the output signal timing of the PWM signal to advance the phase of the inverter output voltage when a saturation state occurs in which the inverter output voltage corresponding to the voltage command value cannot be obtained by the increase control of the pulse width of the PWM signal. A motor control device for performing position sensorless drive by estimating a rotor position based on a phase induced voltage in consideration of an armature reaction dependent on the amount of current of the motor in the control of performing the motor control. 2. A motor current amount is estimated from a voltage between output terminals of a rectifier circuit, a pulse width of a PWM signal, and a motor rotation speed, and a leading phase angle of a phase induced voltage due to an armature reaction is calculated based on the estimated current amount. The motor control device according to claim 1, wherein the rotor position is estimated based on the corrected phase induced voltage. 3. The motor control device according to claim 1, wherein the control for increasing / decreasing the pulse width of the PWM signal and the field weakening control are performed in consideration of a delay until the pulse width acts on the motor drive. 4. The circuit according to claim 1, wherein an inrush current preventing circuit for protecting a peripheral device circuit from an inrush current flowing to charge a capacitor connected between output terminals of the rectifier circuit when the power is turned on is not provided. Motor control device.