JPH0779588A - SR motor controller - Google Patents

Abstract

(57) [Abstract] [Purpose] The SR motor control device is
Moreover, it is controlled with low torque ripple. [Structure] An angle sensor 2 for detecting a rotation angle of a rotor is attached to an SR motor 1, and the detected value is input to a control unit 3 together with a torque command signal from a torque command generation unit 6. The control unit determines the energization phase and applied voltage to the SR motor based on these signals. The power head drive unit 5 is operated according to the determined energization command value, and the power from the power supply 4 is supplied to the stator winding of the SR motor. At this time, the current flowing in the stator winding is the current detection sensor 7
The torque ripple is estimated from the detected current change pattern, and if the torque ripple is estimated to be large, then in the operation range where it is easy to feel, the torque ripple should be reduced with respect to the energization phase and applied voltage. Make corrections. Thereby, a desired torque can be generated with high driving efficiency and low torque ripple.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an SR motor controller.

[0002]

2. Description of the Related Art Generally, SR (Switched Re)
A luctance motor produces a magnetic field by passing an exciting current through an exciting winding, exerts magnetism on a rotor by the action of this magnetic field, and an attractive force or a magnetic force generated between them causes a magnetic force to be generated on a protrusion of the rotor. This is a configuration in which the repulsive force is used to generate the rotational torque. Therefore, when controlling the output, it suffices to control the exciting current corresponding to the exciting winding. However, in the SR motor, when a constant exciting current is applied to the exciting winding, the torque generated in the rotor is not constant and changes according to the rotation angle of the rotor. Particularly, when the protrusion of the rotor and the magnetic pole of the stator are close to each other, almost no output torque is generated, and the exciting current causes heat generation in the exciting winding. Therefore, when a constant exciting current is applied to the exciting winding when a predetermined output is required, a part of the exciting current is wastefully consumed and a torque ripple is generated in the rotor, resulting in stable output. Not only torque cannot be obtained, but also drive efficiency is reduced.

On the other hand, as an SR motor control device for improving the driving efficiency and obtaining a stable output torque, there is one proposed by the applicant in Japanese Patent Application No. 5-214992. This is a device in which the power supply voltage is applied to the SR motor as it is and is controlled by the energization start angle and the energization phase such as the energization width.

Here, the energization start angle and the energization width are shown in FIG.
As shown in, while the rotor is rotating clockwise,
When the energization of the winding of the C salient pole is started, the angle of the point A of the rotor with respect to the point B is the energization start angle, and the angle at which the point A moves from the start to the end of the energization is the energization width. In order to drive the SR motor, it is highly efficient to keep the voltage applied to the motor high and control the output torque by using the energization phase, that is, the energization start angle and the energization width that is the time for energizing the winding. Therefore, in the SR motor controller proposed above, the SR
The characteristic of the control parameter that maximizes the efficiency of the motor is that the PWM duty ratio is 100 so that the applied voltage is high.
%, And the generated torque is changed by the energization start angle and the energization width. For example, if the energization width is widened, the time to apply the voltage to the winding increases, so the effective value of the current flowing in that winding increases, and if the energization start is made before the angle at which the stator salient poles and rotor salient poles begin to overlap. Since the voltage is applied while the winding inductance is small, the current rises quickly, and eventually the effective value of the current increases and a large torque can be obtained.

[0005]

However, if the applied voltage is kept high in the low torque output region, the energization width must be narrowed, so that the torque ripple becomes lower as the rotation speed becomes lower at the low rotation speed of the rotor. Is increasing. On the other hand, in order to reduce the amount of torque ripple, for example, the energization width may be widened and controlled by the applied voltage. However, as described above, it is efficient to keep the voltage applied to the SR motor high and control the output torque by using the time during which the winding is energized, that is, the energization width. In the output range or high rotation speed range, the efficiency will decrease. Therefore, according to the present invention, a highly efficient drive state can be obtained in a region where torque ripple is unlikely to occur, smooth driving can be performed in a region where torque ripple is likely to occur, and efficiency is generally high in a wide range of rotation speed and output torque. Low torque ripple S
An object is to provide a control device for an R motor.

[0006]

Therefore, the present invention according to claim 1 is to provide a torque command generating means for an SR motor, a rotation angle detecting means for detecting a rotation angle of a rotor of the SR motor, and the rotation angle. Computation means for computing the rotation speed of the rotor based on the detection value of the detection means, and controlling the exciting current to the stator winding of the SR motor corresponding to the rotation speed of the SR motor and the output torque of the SR motor. An energization data storage means for storing in advance data of energization phase such as energization start angle and energization width, and applied voltage is provided, and the energization data storage means stores the data according to the rotation speed calculated by the calculation means and the torque command by the torque command generation means. Control means for reading and outputting a control command for the exciting current from the energization data storage means,
Drive means for driving the SR motor based on the control command output by the control means.

According to a second aspect of the invention, the torque command generating means for the SR motor, the rotation angle detecting means for detecting the rotation angle of the rotor of the SR motor, and the rotor based on the detection value of the rotation angle detecting means. Calculating means for calculating the rotation speed of the SR motor, torque detecting means for detecting the load torque of the SR motor, current detecting means for detecting the current to the stator winding of the SR motor, and the rotation speed of the SR motor. The SR according to the output torque of the SR motor
An energization data storage unit that stores in advance data of energization phase such as energization start angle and energization width for controlling the excitation current to the stator winding of the motor and energization width and applied voltage is provided, and the rotation speed calculated by the calculation unit and the Control means for reading out and outputting an excitation current control command from the energization data storage means in response to a torque command from the torque command generation means, detection values of the torque detection means and the current detection means, and the calculated rotational speed. According to the above, a correction unit that corrects the control command read from the energization data storage unit and a drive unit that drives the SR motor based on the corrected control command are provided.

[0008]

In the invention according to claim 1, in the control means,
Two types of energization data for which maximum efficiency is obtained and energization data for which minimum torque ripple is obtained are stored in the storage means in advance in a range where torque ripple is likely to occur based on the rotation speed of the SR motor and the torque command value. The stored low torque ripple control command is read and the high efficiency control command is read and output in the region where torque ripple is less likely to occur, so the SR motor is driven under high drive efficiency and low torque ripple over a wide drive range. To be done. According to the second aspect of the invention, the current flowing in the stator winding is detected, the torque ripple amount is estimated from the change in the detected current, the drive state is determined, and the energization data in the case of high torque ripple is determined according to the determination result. Since the energization command read by the storage means is corrected, the torque ripple is minimized and the SR motor is driven efficiently. Further, even if the driving state changes suddenly, the driving is smoothed.

[0009]

FIG. 1 shows a first embodiment of the present invention. SR
The motor 1 is composed of a stator winding, a rotor, and the like, which are not shown in the figure, and the rotor rotates according to the exciting current applied to the stator winding. An angle sensor 2 is attached as detection means for detecting the rotation angle of the rotor, and outputs a rotation angle signal according to the rotation angle. This rotation angle signal is input to the controller 3 together with the torque command signal from the torque command generator 6. Based on these signals, the control unit 3 reads the energization start angle and energization width of the SR motor from the internal memory provided in the control unit, the energization phase such as the energization width, and the value of the applied voltage, and determines the energization command for controlling the excitation current. . The output device in the control unit 3 operates the power head drive unit 5 in accordance with the determined energization command value, and the power from the power supply 4 is supplied to the stator winding of the SR motor according to the operation of the power head drive unit 5. It

The torque generated in the rotor when a constant current is applied to the one-pole winding changes with the rotation of the rotor. As shown in FIG. 2, the relationship between the rotation angle of the rotor and the output torque is zero when the energization start angle is zero, and the output torque increases as the energization start angle increases. . When the maximum value is exceeded, the output torque gradually decreases, and when the center point of the salient poles of the stator and the center point of the salient poles of the rotor match, the output torque becomes zero again. Therefore, the winding of each salient pole of the stator is energized when the energization start angle is zero, and when the energization start angle of the next salient pole becomes zero, the power source is switched to the winding of that salient pole in sequence. When energized, the torque ripple amount increases as shown in FIG. On the other hand, when the salient poles of the stator and the salient poles of the rotor start to overlap with each other, that is, the energization starts after the energization start angle has passed to some extent, and the energization width is such that the windings of each phase are slightly overlapped, It can be seen that the amount of ripple becomes small as shown in FIG. Therefore, the torque ripple amount is related to the energization start angle and the energization phase such as the energization width. Therefore, in order to reduce the torque ripple, the energization phase is determined in advance and the applied voltage is controlled when the torque generated by the SR motor is controlled. Need to change.

Therefore, in order to perform the most efficient control with a small torque ripple, the control unit 3
Has an internal memory, calculates the energization start angle, the energization width, and the applied voltage corresponding to the rotation speed and torque divided into appropriate sections, and stores the results as two types of maps. That is, FIGS. 5, 6, and 7 are maps in a two-dimensional format that maximizes efficiency. FIG. 5 shows the relationship between the energization start angle, the torque, and the rotation speed. Fig. 6 shows the relationship between the energization width, torque, and rotation speed.
FIG. 7 shows the relationship among applied voltage, torque, and rotation speed.
Similarly, the energization start angle that minimizes the torque ripple,
The energization width and the applied voltage are calculated, and the result is stored as a two-dimensional map.

When the detection value of the angle sensor 2 is input to the control unit 3, the actual rotation speed and rotation acceleration are calculated by the calculation unit in the control unit based on the detection value of the angle sensor.
The torque ripple is detected by this change in rotational acceleration,
When the amount reaches a predetermined amount or more, the map is switched to a map that minimizes the torque ripple amount stored in the internal memory. Then, based on the previous calculated value of the rotation speed, the energization voltage according to the torque command value from the torque command generator 6,
The energization command such as energization start angle and energization width is read,
It is output to the power head drive unit 5 and drives the SR motor.

This embodiment is constructed as described above, and two types of maps, a map for maximizing efficiency and a map for minimizing torque ripple amount, are stored in the internal memory. Since the map is selected according to the magnitude of the torque ripple when determining the energization command, the energization command with the highest efficiency and the minimum torque ripple is determined. As a result, when both the rotation speed and the load are small such that the torque ripple is not so noticeable when the vehicle is descending a downhill slope, the control is performed according to the map that maximizes the efficiency. You can control. Therefore, it is possible to obtain the effect that the driving with high efficiency and low torque ripple is maintained over a wide range of rotation frequency and output torque.

The map of the control parameters in the low rotation range where the torque ripple is remarkable may be stored so as to minimize the torque ripple amount and maximize the efficiency in the rotation range beyond that.

FIG. 8 shows a second embodiment. In this embodiment, a current detector 7 for the exciting current generated by the exciting winding is further provided in the first embodiment shown in FIG. The exciting current generated in the exciting winding detected by the current detector is input to the controller 13 together with the angle signal from the angle sensor 2 and the torque command signal from the torque command generator 6.
The other structure is the same as that of the first embodiment.

This embodiment is driven by a control parameter map that maximizes the efficiency as shown in FIGS. 5, 6 and 7, and when the occurrence of torque ripple is detected, the control parameter is set to the minimum torque ripple. This is a method of reducing the torque ripple by making a correction. The amount of torque ripple is detected by the change in the current flowing through the stator winding.

FIG. 9 shows one variation pattern of the current flowing through the stator winding of the SR motor. Since a square wave voltage is applied, the current flows through the one pole winding while changing. As shown in FIG. 9, the pattern is defined such that the peak value is h and the width is A. The torque ripple becomes large when the ratio Q of the peak value h to the width A is large, but the ratio Q is different depending on the load condition such as the rotation speed and the road surface. It is necessary to change Q. The rotation speed is obtained by calculating a signal from the rotor angle sensor 2 provided in the SR motor from, for example, an increase amount per unit time, and the load condition such as a road gradient is obtained from a torque command generating means such as an accelerator. Estimate from the torque command value to the vehicle and the actual vehicle acceleration. The vehicle acceleration can also be known from the amount of change in the motor rotation speed.

The correction for changing the peak value of the stator current and the ratio Q of the width may be made as shown in FIG. 10 according to the rotational speed and the load condition obtained as described above. If the rotation speed is above a certain level, the torque ripple is not noticeable, so drive with a combination of control parameters that maximizes efficiency. Therefore, even if the crest value is larger than the width, it is driven without correction. In a region where the rotation speed is low and torque ripple is easily felt, the control parameter is corrected when the peak value of the current waveform is larger than the width by a certain ratio Q or more. The correction is, for the purpose of lowering the peak value, lowering the applied voltage, for example, lowering the duty ratio of PWM,
The energization width is widened correspondingly and the energization start angle is delayed. However,
When the road surface load is small, such as downhill, torque ripple is less likely to be felt, so correction is unnecessary or slight.

Since this embodiment is constructed as described above and the torque ripple is estimated from the change pattern of the winding current, it is not necessary to additionally provide a torque ripple detecting means. Further, since the control parameter is corrected according to the current change pattern and the estimated load condition, the control parameter can be smoothly switched. The present invention is not limited to the above-described embodiment, and an acceleration sensor may be provided in the motor to directly detect vibration due to torque ripple and correct the control parameter accordingly. The same result can be obtained even if the control parameter is corrected by providing the acceleration sensor on the vehicle side or detecting the torque ripple of the motor by processing the signal of the speed sensor.

[0020]

As described above, according to the present invention, in the control means, the energization read out from the storage means in which the energization data is stored in advance based on the rotation speed of the SR motor and the required torque command value. Since the control signal is output from the value of the phase and the applied voltage, in the operating range where the torque ripple tends to be remarkable, the setting of the control parameter that maximizes the efficiency switches to the setting of the control parameter that minimizes the torque ripple. The effect that the SR motor is driven under the torque ripple and the high driving efficiency is obtained.

Further, the waveform of the current flowing through the stator winding is detected, the torque ripple amount is estimated from the detected waveform, and the values of the energization phase and the applied voltage read from the energization data storage means are corrected. With this configuration, the effect of minimizing the torque ripple and efficiently driving the SR motor can be obtained. As a result, the drive efficiency is good, and the effect that the torque ripple can be kept to a minimum in a wide range of output torque is obtained.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a first exemplary embodiment of the present invention.

FIG. 2 is a diagram showing a relationship between an SR motor generated torque and a rotor angle.

FIG. 3 is a diagram showing the relationship between the SR motor generated torque and the rotor angle when the energization start angle is zero.

FIG. 4 is a diagram showing the relationship between the SR motor generated torque and the rotor angle when the energization start angle is not zero and the energization widths of other windings overlap.

FIG. 5 is a diagram showing a relationship between a torque, a rotation speed, and an energization start angle for obtaining maximum efficiency.

FIG. 6 is a diagram showing the relationship between torque, rotation speed and energization width for obtaining maximum efficiency.

FIG. 7 is a diagram showing a relationship between torque, rotation speed and applied voltage for obtaining maximum efficiency.

FIG. 8 is a diagram showing a configuration of a second exemplary embodiment of the present invention.

FIG. 9 is a diagram showing an example of a change pattern of a current flowing through a stator winding.

FIG. 10 is a diagram showing the relationship between the degree of correction, the rotational speed of the rotor, and the load.

FIG. 11 is a diagram showing a relationship between a torque generated in the rotor and a rotation angle of the rotor when a constant current is applied to the stator winding.

[Explanation of symbols]

 1 SR motor 2 angle sensor 3, 13 control unit 4 power supply 5 power head drive unit 6 torque command generation unit 7 current sensor

Claims (2)

[Claims] 1. An SR motor torque command generation means, a rotation angle detection means for detecting a rotation angle of a rotor of the SR motor, and a calculation means for calculating a rotation speed of the rotor based on a detection value of the rotation angle detection means. And data of energization phase and applied voltage such as energization start angle and energization width for controlling the exciting current to the stator winding of the SR motor corresponding to the rotation speed of the SR motor and the output torque of the SR motor. Control means which comprises energization data storage means stored in advance, and which reads out and outputs an excitation current control command from the energization data storage means in accordance with the rotation speed calculated by the calculation means and the torque command by the torque command generation means. And a drive unit for driving the SR motor based on a control command output by the control unit. Control device. 2. A SR motor torque command generating means, a rotation angle detecting means for detecting a rotation angle of a rotor of the SR motor, and a calculating means for calculating a rotation speed of the rotor based on a detection value of the rotation angle detecting means. Corresponding to the torque detection means for detecting the load torque of the SR motor, the current detection means for detecting the current to the stator winding of the SR motor, the rotation speed of the SR motor and the output torque of the SR motor. Then, an energization data storage means for storing in advance data of energization phase such as energization start angle and energization width and applied voltage for controlling the exciting current to the stator winding of the SR motor is provided, and is calculated by the calculation means. Control means for reading out and outputting an excitation current control command from the energization data storage means in response to a rotation speed and a torque command from the torque command generation means; Correction means for correcting the control command read by the energization data storage means according to the detected values of the torque detection means and the current detection means and the calculated rotation speed, and based on the corrected control command And a drive unit that drives the SR motor.