JP2007028780A - Motor drive control device - Google Patents

Abstract

A driving method for canceling torque ripple based on a spatial harmonic of a magnetic flux of a motor is realized without measuring in advance.
An instantaneous motor induced voltage is calculated from an applied voltage and current to a motor and an inductance of the motor, and an instantaneous torque is calculated using the calculated induced voltage and current. The voltage applied to the motor is adjusted so as to match the torque. As a result, the torque is insufficient where the induced voltage is reduced due to the spatial harmonics of the magnetic flux, the applied voltage is increased to increase the torque, the motor current is increased, and the torque is increased. Control is performed so as to increase, and the generated torque approaches a desired value.
[Selection] Figure 2

Description

  The present invention relates to a drive control device for a motor, and more particularly to a drive control device that achieves quiet driving with a constant torque generated from the motor.

  Conventionally, an IPM motor in which a permanent magnet is embedded in a rotor is known as a high-efficiency motor. Further, on the stator side, a concentrated winding structure in which an electric wire is wound without straddling a slot is known. In this concentrated winding IPM motor, the spatial harmonics of the magnetic flux are large, and problems such as motor efficiency and torque ripple occur.

  In order to deal with this problem, Non-Patent Document 1 attempts to check the spatial harmonics of the magnetic flux in advance and cancel the torque ripple due to the spatial harmonics using a voltage equation including the spatial harmonics.

Also, Patent Document 1 discloses a method in which torque ripple components are examined in advance and stored in a low-capacity ROM.
Kantaro Yoshimoto, Yasuhiko Kitajima and 2 others “IPMSM Harmonic Current Control (RM-03-50)” The Institute of Electrical Engineers of Japan, July 10, 2003 JP-A-11-55986

  However, in the conventional configuration, it is necessary to know the spatial harmonics of the magnetic flux. Depending on the motor to be driven, the state of the spatial harmonics changes depending on the load state, and the spatial harmonics are measured in more detail. Therefore, there is a problem that canceling torque ripple cannot be realized for general purposes.

  The present invention solves the above-described conventional problems, and calculates the instantaneous induced voltage of the motor using parameters such as the voltage and current applied to the motor, the inductance of the motor, and the obtained induced voltage and By calculating the instantaneous torque from the current, etc., and controlling the motor current so that the instantaneous torque does not have ripples, the torque ripples can be measured without measuring spatial harmonic information in advance. An object of the present invention is to provide a motor drive control device that can suppress generation.

  In order to solve the above-described conventional problems, the motor drive control device of the present invention calculates an instantaneous motor induced voltage from the applied voltage and current to the motor and the inductance of the motor, and uses the calculated induced voltage and current. The instantaneous torque is calculated, and the voltage applied to the motor is adjusted so that the calculated torque matches the desired torque.

  As a result, when the induced voltage is reduced due to the spatial harmonics of the magnetic flux, the torque becomes insufficient, and the motor current is increased to increase the torque, and control is performed so that the torque increases. Thus, the generated torque approaches a desired value.

The motor drive control device of the present invention can suppress the torque ripple caused by the spatial harmonic component of the magnetic flux of the motor without knowing the magnitude of the harmonic component in advance, thereby realizing quiet motor drive. be able to.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a circuit block diagram showing an overall circuit configuration of a motor drive control device according to a first embodiment of the present invention.

  In FIG. 1, a three-phase bridge circuit 4 is connected to a DC power source 5, and the motor 1 is connected to the output of the three-phase bridge circuit 4. In the drive control of the motor 1, the current to the motor 1 is detected by the current detectors 6 and 7, the rotation state of the motor 1 is detected by the rotation detector 2, and the generation accuracy of the voltage applied to the motor 1 is improved. In addition, the voltage of the DC power source 5 is detected, and the control circuit 3 gives a control signal to the three-phase bridge circuit 4 based on the result, thereby driving the motor 1.

  The operation / action of the control circuit 3 in the motor drive control device configured as described above will be described.

FIG. 2 is a block diagram showing an operation flow in the control circuit 3.
In FIG. 2, a speed command ω * is input from the outside, and the detected speed ω obtained by the speed detector 2 is compared with the comparison circuit 202. The comparison result is sent to the PI compensation unit 203 and the gain adjustment unit 210 as a speed error. The PI compensation unit 203 performs a compensation calculation so as to stabilize the speed, and sends the calculation result to the addition unit 308. The adding means 208 adds the output result of the multiplication circuit 209 and sends the result to the comparing means 204 as a current command value I *. The comparison unit 204 compares the current command value with the detected current and sends the result to the PI compensation unit 205. The PI compensation unit 205 performs a compensation calculation so that the current is stabilized, and the result is added to the output result of the reverse motor characteristic calculation unit 207 by the addition circuit 206 to obtain the voltage value as the three-phase bridge circuit of FIG. 4 is driven to apply a voltage to the motor 201. In the motor 201, when a voltage is applied, a current flows to generate a rotational torque and rotate. The operation so far is the same as that of a speed control system having a general current control in an inner loop.

  Next, the speed error sent to the gain adjusting means 210 is sent to the torque comparing means 218 as an average torque command. The estimated torque to be compared will be described. The instantaneous induced voltage in the motor 201 is calculated from the instantaneous instantaneous applied voltage V and current I to the motor 201. The induced voltage can be calculated as a value obtained by subtracting the voltage component due to the impedance component and current of the motor 201 from the applied voltage. Here, the impedance component is the resistance and inductance of the motor 201.

  If the instantaneous induced voltage calculated in this way is divided by the rotational speed at that time, a torque constant, that is, a proportional coefficient between current and torque is obtained. Therefore, at this time, the instantaneous torque can be calculated by using the instantaneous current. In the case of a motor that can use the inductance of the motor as the torque generation, the torque may be calculated in consideration of the inductance value.

The difference between the instantaneous torque calculated in this way and the torque command obtained from the speed error is calculated by the comparison means 218 to obtain an instantaneous torque error. The obtained instantaneous torque error is sent to the adding means 214 via the high-pass filter (HPF) 213, and is added again with information obtained by delaying the output of the adding means 214 by one rotation period. The output of the adding means 214 is sent to the one-rotation period delay means 215 via the gain adjusting means 216, circulated again to the adding means 214, and sent to the δθ advancement means 217. The output of the δθ phase advance means 217 is sent to the multiplication means 209 and is multiplied by the output of the PI compensation means 203 of the speed control system. The multiplication result is sent to the motor inverse characteristic calculation means 207 and the addition means 208. The motor reverse characteristic calculation means 207 reversely calculates the voltage when a predetermined current is flowing through the motor 201. That is, a voltage for generating a current necessary for making the instantaneous torque constant is calculated. The calculation result of the motor reverse characteristic calculation means 207 is sent to the addition means 207, and added to the calculation result of the PI compensation calculation means 205 of the current control system to obtain the applied voltage to the motor 201.

  Next, the cooperation between the normal speed control and current control method and the instantaneous torque estimation control method will be described. FIG. 4A shows the frequency characteristics of the information processing system composed of the adding means 214, gain adjusting means 216, and one rotation period delay means 215 in FIG. Further, the dotted line in FIG. 2A shows the characteristics of the high-pass filter 213 arranged in front of FIG. In the figure (a), since components other than an integral multiple of the frequency of one rotation cycle are not added, the filter has a comb filter characteristic that allows only an integral multiple of the frequency of one rotation cycle to pass. Since the high-pass filter 213 is connected before this, as shown in FIG. 5B, zero-times information is cut off, and only the harmonic component of the magnetic flux can be extracted.

  The harmonic component of the magnetic flux extracted in this way is sent to the multiplication unit 209 with the δθ phase advance means canceling out the information delay caused by the calculation means or the like. The multiplication means uses a characteristic in which the magnitude of the harmonic component of the magnetic flux is approximately proportional to the magnitude of the average magnetic flux. Since the magnitude of the average magnetic flux corresponds to the current value, multiplication is performed. Thus, it is automatically modulated to a substantially appropriate amplitude. Even if there is a deviation in amplitude, the constant instantaneous torque control system is also feedback control, so that error is absorbed.

  The multiplication result is added to the current command by the adding means 208, and the voltage corresponding to the current at that time is calculated via the calculating means having the reverse characteristics of the motor, and the voltage is directly modulated. The calculation means having characteristics opposite to those of the motor also includes a deviation from the true motor characteristics, but the error is absorbed because the constant instantaneous torque control system is feedback control. The reason why an arithmetic means having a characteristic opposite to that of a motor is used is that the control of a three-phase bridge circuit as shown in FIG. 1 is generally performed by pulse width modulation, and an applied voltage for realizing a desired current is used. This is to realize a high-speed response that cannot be realized by current control, because the change period is a pulse modulation period and the response of current control is limited by the period. In general, the response time of the control system is one digit slower than the control period in the three-phase bridge circuit, and cannot be followed by current feedback control when the motor is rotating at high speed. .

  As described above, in the present embodiment, normal current control can follow up by calculating only the instantaneous torque and extracting only the harmonic component and directly operating the applied voltage in order to keep it constant. It is possible to keep the torque constant up to a high-speed region, which enables high-efficiency and quiet driving.

(Embodiment 2)
FIG. 3 is a block diagram showing a flow of control information of the motor drive control device according to the second embodiment of the present invention. The basic configuration is the same as in the first embodiment, and the same numbers are assigned to the same elements. In FIG. 3, the output of the δθ phase advance means 217 is input to the reverse motor characteristic calculation means 207 and the current command value addition means 308 without going through the multiplication means. When there is no sudden change in the torque to be used, information on the harmonic component of the magnetic flux is gradually accumulated in the one-rotation period delay means 215, so that it can be practically simplified as shown in FIG. .

In the first and second embodiments, the high-pass filter 213 is disposed in front of the delay unit, but it goes without saying that the same effect can be obtained either before the δθ phase advance unit or before the multiplier unit 209. .

  As described above, the motor drive control device according to the present invention can quietly drive a high-efficiency motor without inputting magnetic flux distortion information in advance. Applicable to a wide range of applications such as electrical equipment.

1 is an overall circuit block diagram of a motor drive control device according to an embodiment of the present invention. Block diagram showing information processing of a control circuit in the motor drive control device in Embodiment 1 of the present invention Block diagram showing information processing of a control circuit in the motor drive control device in Embodiment 2 of the present invention Frequency characteristic diagram showing the characteristics of the harmonic extraction part in the embodiment

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Motor 2 Rotation detector 3 Control circuit 211 Instantaneous induced voltage estimation means 212 Instantaneous torque estimation means 213 High-pass filter 215 1 rotation period delay means 207 Motor reverse characteristic calculation means

Claims (8)

The instantaneous induced voltage generated by the motor was calculated using the instantaneous value of the AC voltage applied to the motor, the instantaneous value of the AC current flowing through the motor, the winding resistance of the motor, and the motor winding inductance. Calculate the instantaneous torque generated by the motor from the instantaneous induced voltage, the flowing current, and the winding inductance, and manipulate the current flowing through the motor so that the calculated instantaneous torque matches the desired torque. A motor drive control device. Compare the motor rotation speed with the desired rotation speed, change the current command value of the motor based on the comparison result, compare with the current value obtained by driving the motor, and apply the voltage applied to the motor based on the comparison result A motor drive control device for adjusting
The instantaneous induced voltage generated by the motor was calculated using the instantaneous value of the AC voltage applied to the motor, the instantaneous value of the AC current flowing through the motor, the winding resistance of the motor, and the motor winding inductance. The instantaneous torque generated by the motor is calculated from the instantaneous induced voltage, the flowing current, and the winding inductance, and the applied voltage to the motor is operated so that the calculated instantaneous torque matches the desired torque. A motor drive control device. Compare the motor rotation speed with the desired rotation speed, change the current command value of the motor based on the comparison result, compare with the current value obtained by driving the motor, and apply the voltage applied to the motor based on the comparison result A motor drive control device for adjusting
The instantaneous induced voltage generated by the motor was calculated using the instantaneous value of the AC voltage applied to the motor, the instantaneous value of the AC current flowing through the motor, the winding resistance of the motor, and the motor winding inductance. The instantaneous torque generated by the motor is calculated from the instantaneous induced voltage, the flowing current, and the winding inductance. The calculated instantaneous torque is compared with the desired torque, and the comparison result is an integral multiple of the motor rotation speed. A motor drive control device characterized in that the voltage applied to the motor is manipulated by the output of the filter means by inputting to the filter means that allows only information to pass. As a filter means that passes only information that is an integral multiple of the motor rotation speed, a delay means for the rotation period is provided, the output of the delay means is compared with the input, and the comparison result is re-input to the input of the delay means. 4. The motor drive control device according to claim 3, wherein the voltage applied to the motor is operated with information at a time corresponding to a position slightly before the position output by the delay means. The filter means that passes only information that is an integral multiple of the rotation speed of the motor, or the filter means that passes only the information that is an integral multiple of the rotation speed of the motor. 5. The motor drive control device according to claim 4, further comprising a high-pass filter for removing a direct current component in front of the motor drive control device. 4. The output information of the filter means that passes only information that is an integral multiple of the rotational speed of the motor is multiplied by the command current value based on the speed error, and the voltage applied to the motor is manipulated according to the multiplication result. The motor drive control device described. A means for manipulating the applied voltage to the motor and a high-pass filter means for removing a DC component are connected in series via a filter means for passing only information that is an integral multiple of the motor rotation speed, and obtained from the output. The obtained voltage value is input to the relational expression for obtaining the required voltage when the motor current is input, and the obtained voltage value is added to the applied voltage value to the motor obtained by the current control based on the speed error. The motor drive control device according to claim 5, wherein A relational expression that calculates the necessary voltage when the motor current is input by multiplying the output information of the filter means that passes only information that is an integral multiple of the motor rotation speed with the command current value based on the speed error. The motor drive control device according to claim 6, wherein the voltage value obtained by inputting to the motor is added to a voltage value applied to the motor obtained by current control based on a speed error.

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