JP2011234528A - Synchronous-motor control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a synchronous-motor control device which allows stable operation even if the operating rotational-frequency range includes the resonance frequency.SOLUTION: A frequency correction amount obtained from detected values of at least two phases of electric current running through windings of a synchronous motor 10 and from a phase determined by integrating frequency references is used as input into a notch filter 12 attenuating only frequency components at or near the axial resonance frequency, to calculate a new frequency correction amount.

Description

  The present invention relates to a position sensorless synchronous motor control device for controlling a voltage applied to a winding of a synchronous motor and a frequency thereof using a power converter such as an inverter.

  As simple position sensorless control of a conventional synchronous motor, for example, V / F constant control as described in Patent Document 1 and Non-Patent Document 1, Patent Document 2 and Non-Patent Document 2 are described. Such primary magnetic flux constant control is well known.

  In the control of these conventional synchronous motors, by feeding back to the frequency command the frequency correction amount obtained from the detected value of at least two-phase current flowing through the winding of the synchronous motor and the phase obtained by integrating the frequency command, The speed control system is stabilized to prevent step-out when the load fluctuates.

JP 2000-236694 A JP 2000-262088 A

Ito, Junichi, Toyosaki, Jiro and Osawa, Hiroshi, "Performance improvement of V / f control of permanent magnet synchronous motor", Electrical Engineering D, Vol. 122, No. 3, 2002, 253-259 Hideaki Hamada, Naoki Yamamura, and Joe Tsunehiro, “General-purpose inverter for synchronous machine drive”, D. D. 119, 5, 1999, 707-712

  The rotor position detector is not only a major factor that hinders downsizing of the equipment, but also requires multiple wires and receiving circuits to transmit the rotor position detector signal, so reliability, workability, There was a problem with the price.

  In addition, the method of calculating the rotor position indirectly from the voltage and current information of the motor without using a position detector requires a complicated and high-speed calculation process, so that the control device becomes expensive. there were.

  Conventional V / F constant control and primary magnetic flux constant control with frequency correction can be made inexpensive because the control is simple, but the resonance of the rotor and its support system is within the range of operating speed of the synchronous motor. When there is a frequency, there is a problem that the power supplied to the synchronous motor increases near the resonance frequency, and the frequency correction conversely prevents the operation through the resonance point, so that the target rotational speed cannot be increased.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a synchronous motor control device that can operate stably even when there is a resonance frequency in the operating rotational speed range. And

  A control apparatus for a synchronous motor according to the present invention is based on a frequency command calculating means for calculating a frequency command, an adding / subtracting means for generating a new frequency command by subtracting a frequency correction value from the frequency command, and the new frequency command. A voltage command calculating means for calculating a voltage command, an integrating means for integrating the new frequency command and outputting phase information, and a dq / that converts the voltage command into a three-phase voltage command based on the phase information. Three-phase conversion means, PWM means for generating a gate drive command from the three-phase voltage command, and a voltage applied to the synchronous motor winding based on the gate drive command and its frequency to drive the synchronous motor Based on the phase information, three-phase / dq conversion means for converting the current flowing in the winding of the synchronous motor into a biaxial current component, and the biaxial current component A notch filter for attenuating only the resonance frequency of the rotor of the synchronous motor and frequency components before and after the synchronous motor rotor, a high-pass filter for removing a DC component from the output signal of the notch filter, and the high-pass filter And a proportional amplifier that multiplies the output signal by a gain and outputs the frequency correction value.

  According to the control apparatus for a synchronous motor according to the present invention, the frequency command does not vibrate even if the resonance frequency of the rotor and its support system is within the operating rotational speed range of the synchronous motor, so that the resonance frequency passes stably. Is possible.

It is a block diagram which shows the structure of the control apparatus of the synchronous motor which concerns on Embodiment 1 of this invention. It is a timing chart which shows the rotation speed and q-axis current when a synchronous motor is drive | operated by fixed acceleration in the control apparatus of the synchronous motor which concerns on Embodiment 1 of this invention. It is a figure which shows the frequency transfer characteristic of the notch filter of the control apparatus of the synchronous motor which concerns on Embodiment 1 of this invention. It is a block diagram which shows the structure of the control apparatus of the synchronous motor which concerns on Embodiment 2 of this invention. It is a figure which shows the gain table (frequency-gain) of the gain memory | storage means of the control apparatus of the synchronous motor which concerns on Embodiment 2 of this invention.

  A preferred embodiment of a control apparatus for a synchronous motor according to the present invention will be described below with reference to the drawings.

Embodiment 1 FIG.
A control apparatus for a synchronous motor according to Embodiment 1 of the present invention will be described with reference to FIGS. 1 is a block diagram showing a configuration of a control apparatus for a synchronous motor according to Embodiment 1 of the present invention. In the following, in each figure, the same reference numerals indicate the same or corresponding parts.

  1, the control apparatus for a synchronous motor according to the first embodiment of the present invention includes a frequency command calculation unit 1 that calculates a frequency command, and an addition / subtraction unit that generates a new frequency command by subtracting a frequency correction value from the frequency command. 2, voltage command calculation means 3 for calculating a voltage command based on a new frequency command, voltage command correction calculation means 4 for calculating a correction voltage command based on the new frequency command, a voltage command and a correction voltage command An adding means 5 for adding, an integrating means 6 for integrating new frequency commands and outputting phase information θ, and a dq / 3 phase for converting the added voltage command into a three-phase voltage command based on the phase information θ The converter 7, the PWM unit 8 that generates a gate drive command from the three-phase voltage command, and the voltage applied to the winding of the synchronous motor 10 based on the gate drive command and the frequency thereof are controlled synchronously. An inverter 9 that drives the motor 10, a three-phase / dq conversion means 11 that converts a current flowing through the winding of the synchronous motor 10 into a two-axis current component based on the phase information θ, an axial resonance frequency, and frequencies before and after that. A notch filter 12 that attenuates only the component, a high-pass filter 13 that removes a DC component, and a proportional amplifier 14 that multiplies the gain and outputs a frequency correction value are provided.

  Next, the operation of the synchronous motor control device according to the first embodiment will be described with reference to the drawings.

  First, the frequency command calculation means 1 calculates a frequency command for driving the synchronous motor 10. Two-phase or more currents flowing through the windings of the synchronous motor 10 are detected by CT, and the three-phase / dq conversion means 11 converts the detected current into a biaxial current component based on the phase information θ. The notch filter 12 uses one of the two-axis current components (q-axis current Iq) as an input signal, and attenuates the resonance frequency of the rotor (not shown) of the synchronous motor 10 and the frequencies around it. The high pass filter 13 removes a DC component from the output signal of the notch filter 12. The proportional amplifier 14 multiplies the output signal of the high pass filter 13 by a gain and outputs a frequency correction value.

  The adder / subtractor 2 subtracts the frequency correction value of the proportional amplifier 14 from the frequency command of the frequency command calculator 1 to generate a new frequency command. The accumulating means 6 accumulates new frequency commands and outputs phase information θ.

  The voltage command calculation means 3 calculates a voltage command based on a new frequency command. The voltage command correction calculation means 4 calculates a correction voltage command based on the new frequency command. The adding means 5 adds the voltage command from the voltage command calculating means 3 and the correction voltage command from the voltage command correction calculating means 4.

  The dq / 3-phase conversion means 7 converts the added voltage command into a three-phase voltage command based on the phase information θ. The PWM means 8 generates a gate drive command from this three-phase voltage command. The inverter 9 drives the synchronous motor 10 by controlling the voltage applied to the winding of the synchronous motor 10 and its frequency based on the gate drive command.

  FIG. 2 is a timing chart showing the rotational speed and q-axis current when the synchronous motor is operated at a constant acceleration in the synchronous motor control apparatus according to Embodiment 1 of the present invention.

  2, (a) shows the rotation speed of the rotor of the synchronous motor 10, and (b) shows the q-axis current of the synchronous motor 10, respectively. The current flowing through the windings of the synchronous motor 10 increases as shown by the broken circle in FIG. 2B due to the influence of the rotor shaft vibration that occurs when the resonance frequency of the rotor of the synchronous motor 10 is exceeded. FIG. 2B shows the q-axis current of the synchronous motor 10, and the current vibrates when exceeding the resonance frequency.

  In FIG. 1, the case where there is no notch filter 12 corresponds to the conventional example, but when there is no notch filter 12, the q-axis current is obtained as a frequency correction amount via the high-pass filter 13 and the proportional amplifier 14. The above-described resonance frequency is superimposed on the frequency correction amount.

  In general, it is known that the magnitude of the vibration at the resonance frequency of the rotor depends on the acceleration time. If the acceleration time is long, the vibration due to the resonance grows greatly. For this reason, it is desirable to pass the resonance frequency of the rotor as soon as possible. However, when the notch filter 12 is not provided, the vibration of the resonance frequency component is superimposed on the frequency correction amount. The voltage command calculated based on the phase information θ obtained by integration of the new frequency command obtained from the difference and the new frequency command obtained from the difference between the frequency command and the frequency correction value will vibrate. In this case, the rotor of the synchronous motor 10 will step out.

  FIG. 3 is a diagram showing the frequency transfer characteristics of the notch filter of the synchronous motor control apparatus according to Embodiment 1 of the present invention.

  By setting the attenuation frequency of the notch filter 12 in accordance with the resonance frequency of the rotor of the synchronous motor 10, the rotational speed of the rotor of the synchronous motor 10 as shown in FIGS. It is possible to prevent current oscillations to the synchronous motor 10 when passing through the resonance frequency from being superimposed on the frequency correction value.

  By doing so, even if there is a resonance frequency of the rotor of the synchronous motor 10 in the operating rotation speed range of the synchronous motor 10, it is possible to prevent the frequency command from vibrating, and thus it is possible to pass the resonance frequency stably. become.

  In addition, when the rotational speed of the rotor of the synchronous motor 10 passes through the resonance frequency of the rotor, the voltage is insufficient due to the current vibration of the winding of the synchronous motor 10 and exceeds the resonance frequency of the rotor of the synchronous motor 10. There is a case where the necessary current is not obtained and the step-out occurs.

  In such a case, the voltage (correction voltage command) necessary to exceed the resonance frequency of the synchronous motor 10 is set in the voltage command correction calculation means 4 in advance at the resonance frequency of the rotor of the synchronous motor 10 and the frequencies before and after the resonance frequency. In this case, even if the resonance frequency of the rotor of the synchronous motor 10 is within the operating rotational speed range of the synchronous motor 10, it is possible to pass the resonance frequency stably without stepping out due to insufficient torque.

Embodiment 2. FIG.
A control apparatus for a synchronous motor according to Embodiment 2 of the present invention will be described with reference to FIGS. FIG. 4 is a block diagram showing the configuration of the synchronous motor control apparatus according to Embodiment 2 of the present invention.

  In FIG. 4, the synchronous motor control device according to the second embodiment of the present invention is the same as the synchronous motor control device according to the first embodiment (except for the notch filter 12), and gain storage means 15. , Multiplication means 16 is provided.

  Next, the operation of the synchronous motor control device according to the second embodiment will be described with reference to the drawings.

  FIG. 5 is a diagram showing a gain table (frequency-gain) of the gain storage means of the synchronous motor control apparatus according to Embodiment 2 of the present invention.

  The proportional amplifier 14 inputs a q-axis current Iq, which is one of the two-axis current components obtained by separating into two-axis current components by the three-phase / dq conversion means 11, via the high-pass filter 13, and a frequency correction value. Is output. As shown in FIG. 5, the gain storage means 15 obtains a gain value corresponding to the current frequency command from a gain table set in advance so that the gain value decreases as the frequency command approaches the resonance frequency. Output.

  The multiplying unit 16 multiplies the frequency correction value from the proportional amplifier 14 and the gain value from the gain storage unit 15. That is, the proportional gain of the frequency correction amount is changed according to the frequency command from the frequency command calculation means 1. The adder / subtractor 2 subtracts the multiplication result of the multiplier 16 from the frequency command of the frequency command calculator 1 to generate the new frequency command.

  The notch filter 12 needs to have a high-order digital filter when the number of resonance frequencies to be attenuated is large or the gain of the resonance frequency must be sharply decreased. As the order increases, the number of product-sum operations increases, the processing load on the arithmetic processing unit increases, and it is necessary to use an expensive and high-performance arithmetic processing unit.

  According to the second embodiment, since the gain corresponding to the frequency command is extracted from the gain table stored in advance and this is simply multiplied by the frequency correction value, the number of product-sum operations as in the notch filter 12 is increased. There is no problem.

  Further, unlike the notch filter 12, there is not much product-sum operation processing, and there is no increase in phase lag due to the filter processing. Therefore, a more stable control with a smaller phase lag with an arithmetic device having lower performance than the first embodiment. Is possible.

  1 frequency command calculation means, 2 addition / subtraction means, 3 voltage command calculation means, 4 voltage command correction calculation means, 5 addition means, 6 integration means, 7 dq / 3 phase conversion means, 8 PWM means, 9 inverter, 10 synchronous motor, 11 3 phase / dq conversion means, 12 notch filter, 13 high pass filter, 14 proportional amplifier, 15 gain storage means, 16 multiplication means.

Claims (3)

A frequency command calculating means for calculating a frequency command;
Addition / subtraction means for generating a new frequency command by subtracting a frequency correction value from the frequency command;
Voltage command calculation means for calculating a voltage command based on the new frequency command;
Integrating means for integrating the new frequency command and outputting phase information;
Dq / 3-phase conversion means for converting the voltage command into a three-phase voltage command based on the phase information;
PWM means for generating a gate drive command from the three-phase voltage command;
An inverter that drives the synchronous motor by controlling the voltage applied to the winding of the synchronous motor and its frequency based on the gate drive command;
Three-phase / dq conversion means for converting a current flowing in the winding of the synchronous motor into a biaxial current component based on the phase information;
A notch filter that attenuates only the resonant frequency of the rotor of the synchronous motor and the frequency components before and after the q-axis current which is one of the two-axis current components;
A high-pass filter that removes a DC component from the output signal of the notch filter;
And a proportional amplifier that multiplies an output signal of the high-pass filter by a gain and outputs the frequency correction value. A frequency command calculating means for calculating a frequency command;
Addition / subtraction means for generating a new frequency command by subtracting a frequency correction value from the frequency command;
Voltage command calculation means for calculating a voltage command based on the new frequency command;
Integrating means for integrating the new frequency command and outputting phase information;
Dq / 3-phase conversion means for converting the voltage command into a three-phase voltage command based on the phase information;
PWM means for generating a gate drive command from the three-phase voltage command;
An inverter that drives the synchronous motor by controlling the voltage applied to the winding of the synchronous motor and its frequency based on the gate drive command;
Three-phase / dq conversion means for converting a current flowing in the winding of the synchronous motor into a biaxial current component based on the phase information;
A high-pass filter that removes a DC component from the q-axis current that is one of the two-axis current components;
A proportional amplifier that multiplies the output signal of the high-pass filter by a first gain and outputs the frequency correction value;
Gain storage means for obtaining and outputting a second gain corresponding to the frequency command from the frequency command calculation means from a preset gain table so that the second gain decreases as the frequency approaches the resonance frequency;
A control apparatus for a synchronous motor, comprising: multiplication means for multiplying a frequency correction value from the proportional amplifier by a second gain from the gain storage means and outputting the result to the addition / subtraction means. Based on the new frequency command, a voltage command correction calculation means for calculating a correction voltage command required to exceed the resonance frequency at the resonance frequency of the rotor of the synchronous motor and the frequencies before and after the resonance frequency;
An adding means for adding the voltage command and the correction voltage command;
3. The synchronous motor control device according to claim 1, wherein the dq / 3-phase conversion unit converts the voltage command added by the addition unit into a three-phase voltage command based on the phase information. 4. .

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