JPH0287997A - Rotation controller for variable reluctance motor - Google Patents

Abstract

PURPOSE:To control the rotary speed of a variable reluctance motor quickly to a target rotary speed by correcting the phase winding current value based on a correction value prepared on the basis of the static characteristic of the phase winding current and torque then controlling power conduction for the phase windings. CONSTITUTION:Rotary controller 1 for a variable reluctance motor(SRM) comprises a rotary angle detecting means, i.e., a shaft encoder 2, a F/V con verter 4, a torque command block 6, a current command block 8, a current control block 10 and a drive control block 12. A closed loop control system for controlling the rotary speed of the SRM to a target speed is provided. Since the current value data are corrected based on the correction data prepared on the basis of the non-linear static characteristic of the phase winding current and torque and power conduction for the phase windings L1-L4 is controlled, rotary speed of the SRM can be controlled quickly to a target rotary speed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a rotation control device for a variable reluctance motor.

[Prior Art] Conventionally, as a rotation control device for a variable reluctance motor (hereinafter referred to as an SR motor), the SR motor is used to control the average current flowing through a phase winding to a predetermined level.
It is known to control the rotational speed of an SR motor to a target speed by controlling the average current to increase or decrease in proportion to the magnitude of the torque required to operate the motor at the target rotational speed.

[Problems to be Solved by the Invention] However, the static characteristics of the current flowing through the phase windings and the generated torque in the SR motor are not linear characteristics. That is, as shown in the following equation, its characteristics are expressed by the product of the square of the phase winding current and the inductance change rate of the phase winding, and the inductance changes depending on the phase winding current.

T = k
is the rotation angle of the SR motor) In other words, when a constant current is passed through the phase windings over one electrical cycle, the torque generated by the constant current varies as the rotor rotates, as shown in FIG. Therefore, the above-mentioned rotation control device has a problem in that when the SR motor is operated, a so-called torque ripple occurs and the rotation becomes unstable.

Furthermore, if we look at the static characteristics of the phase winding current and the generated torque with respect to the rotor angle of the SR motor at which the generated torque is maximum, the characteristics are not linear, as shown in FIG. That is, when the current is relatively small, the output torque increases approximately quadratically with respect to the increase in current, and then increases approximately quadratically. When the current further increases, the stator magnetic poles of the SR motor reach 8i saturation, so even if the current is added in total, the generated torque hardly increases.

In short, even if the phase winding current is increased or decreased in proportion to the magnitude of the required torque, the required torque will not be generated. In particular, when the phase winding current is relatively small, that is, when the load on the SR motor is small and the motor rotates at low speed, the generated torque changes approximately quadratically with respect to changes in the phase winding current.
Even by slightly increasing or decreasing the phase winding current, the generated torque will vary greatly. Therefore, the rotational speed device described above has a problem in that the speed control becomes oscillatory.

Therefore, the present invention promptly and stably controls the SR motor to a target speed by controlling the phase winding current in response to the nonlinear correlation characteristic between the phase winding current and the generated torque that the SR motor has. The purpose of this invention is to provide a rotation control device for a variable reluctance motor.

[Means for Solving the Problems] The gist of the present invention is to provide a rotation angle detection means for detecting a rotation angle of a rotor of a variable reluctance motor, and a rotation angle detection means for detecting a rotation angle of a rotor of a variable reluctance motor,
A storage means that stores in advance a phase winding current value corresponding to the rotation angle of the rotor, and corrects the current value stored in the storage means to a phase winding current value for generating a target torque input from the outside. a correction value generating means that generates a correction value for the rotation angle based on the relationship between the torque of the variable reluctance motor and the phase winding current value; correction means for correcting the phase winding current based on the correction value corresponding to the target torque generated by the correction value generation means; There is provided a rotation control device for a variable reluctance motor, characterized in that it is provided with energization control means for controlling energization to phase windings.

[Operations] According to the above configuration of the present invention, first, the rotation angle detection means detects the rotation angle of the rotor of the variable reluctance motor.

Further, when a target torque is commanded from the outside, the correction value generating means generates a phase winding current value for generating the target torque based on the relationship between the torque of the variable reluctance motor and the phase winding current value. . Then, the correction means reads the phase winding current value corresponding to the rotation angle of the rotor detected by the rotation angle detection means from the storage means, and converts the read phase winding current value into the correction value generated by the correction value generation means. Correct based on value. Then, based on the corrected phase winding current value,
The energization control means controls energization to the phase windings of the variable reluctance motor.

[Example code] An embodiment of the present invention will be described based on the drawings.

Rotation control of variable reluctance motor! As shown in FIG. 1, the device 1 includes a well-known shaft encoder 2 as rotation angle detection means, an F/V converter 4, a torque command block 6, a current command block 8, and a current control processor 10. and a drive control block 12, forming a closed-loop control system that controls the rotational speed of a variable reluctance motor (hereinafter referred to as SR motor) SRM to a target speed input from an external speed command device (path shown). There is.

That is, the shaft encoder 2 is attached to the rotation shaft (the path shown in the figure) of the rotor of the SR motor SRM, detects the rotation angle of the rotor, and outputs a rotation angle detection signal θ (pulse). Then, the F/V converter 4 converts the rotation angle detection signal θ input from the shaft encoder 2 into the SR motor S.
Speed signal (voltage signal) Vac corresponding to the rotation speed of RM
t and output to the torque command block 6.

In the torque command block 6, the speed comparator 20 first
The deviation between the speed signal Vact inputted from the /V converter 4 and the target rotational speed signal Vset inputted from the external command device is detected, and a speed deviation signal ΔV is outputted to the well-known proportional-integral calculator 21. The proportional-integral calculator 21 adds the proportional part proportional to the speed deviation and the cumulative part proportional to the cumulative value of the speed deviation, and outputs the target torque command signal T to the current command block 8 based on the result. This target torque command signal T is a voltage signal corresponding to the magnitude of the torque required to control the SR motor SRM to the target rotational speed. Sometimes it is less than the reference voltage.

In the current command block 8, first, the A/D converter 22
A target torque command signal T is input to the target torque command signal T.

The A/D converter 22 converts the target torque command signal T into a digital signal Td having a predetermined number of bits. In this digital signal Td, for example, the most significant bit represents the positive or negative so that it can be identified whether the target torque is positive or negative, and the other bits represent the magnitude of the target torque (absolute value).

Next, the most significant bit signal TMSB of the digital signal Td and the rotation angle detection signal θ are input to the address interface 23.

The address interface 23 is composed of well-known logic elements, up/down counters, etc., and is read-only memory (hereinafter referred to as RO) based on the signal TMSB and the rotation angle signal θ.
30.31, 32.33. Namely, the address interface 23 generates an address signal that specifies an address within the ROM 30.
.about.33 is specified, an address within the area is specified based on the rotation angle signal θ, and an address signal A1. A2.
Create A3゜A4. For example, in the case of a four-phase (8-pole stator, 6-pole rotor) SR motor SRM, each phase winding Ll, L2. L3. Four addresses are specified so that the phase of the current flowing through L4 is shifted by 90 degrees in electrical angle, and the address signals AI, A2 . A3. A4 each ROM3
Output to 0-33.

The same digitized current value data is stored in these ROMs 30-33. This current value data is obtained by setting the phase winding current required for each predetermined electrical angle to generate a torque of a predetermined reference magnitude, and is generally called a current pattern. Current value data for positive and negative torque generation is created and stored in different areas within each ROM 30-33. This current value data is created based on the nonlinear correlation characteristic between the phase winding current and the rotation angle of the rotor when generating the reference torque. For example, as shown in Figure 4, the waveform of the phase winding current when generating the reference torque is
It is measured by actual measurement or simulation, and is created based on this current waveform. An example is shown in FIG.

FIG. 2(A) shows the waveform of the phase winding current when positive torque is generated, and FIG. 2(B) shows the same waveform when negative torque is generated.

This ROM30-33 has an address interface 23.
When the address signal Al-A4 is input from the current value data stored in a predetermined area, the current value is read out from the current value data stored in a predetermined area, and the current value data I'l1, Id2 . Id3.
Multiplying type D/A converters 40 and 41 whose Id4 is well-known
, 42.43.

On the other hand, a signal T BIT of a plurality of bits excluding the most significant bit of the digital signal Td is input to a read-only memory (hereinafter referred to as ROM) 24 .

Then, the ROM 24 stores correction data for correcting the current value data for standard torque generation stored in the ROMs 30 to 33 according to the magnitude of the target torque. (The direct signal Cd is output to the well-known D/A converter 25.

This correction data is set based on the nonlinear static characteristics (shown in FIG. 5) between the phase winding current and the generated torque with respect to the rotor angle of the SR motor at which the generated torque is maximum.

The D/A converter 25 outputs a current correction signal I ref to each multiplication type D/A converter 40 to 43 based on the above correction value signal Cd.

Each of the multiplication type D/A converters 40 to 43 calculates the current required for the target torque based on the current correction signal I ref input as a reference and the current value digital data Idl to Id4, and outputs a current command signal I5etl. ,
I 5et2. I 5et3. I 5et
4 is output to the current control block 10.

Note that the A/D converter 22, ROM 24, and D/A converter 25 correspond to correction value generation means, and the ROMs 30 to 3
3 corresponds to a storage means, and an address interface 23
, the D/A converter 25, and the multiplication type D/A converters 40 to 43 correspond to correction means.

The current control block 10 includes current comparators 50, 51, 52, which are provided for each phase of the SR motor SRM.
53, proportional integral calculator 60. 61. 62.63, well-known pulse width modulation circuit 70. 71.72.73 (hereinafter referred to as a PWM circuit), and an oscillation circuit 80 that outputs a triangular wave Sw to the PWM circuits 70 to 73.

In the current control block 10, first, the current comparators 50 to 5
3, current command signals I5etl to I5et4 are input. The current comparators 50 to 53 receive a current command signal I5e.
tl~I 5et4 and a detection signal (voltage signal) of the phase winding current (actual current) input from the current detector CT, which will be described later.
I actl, I act2. I act3.
Detects a one-dimensional difference from I act4 and generates a current deviation signal Δ
II, ΔI2. ΔI3° and ΔI4 are output to the proportional integral calculators 60 to 63.

The proportional integral calculators 60 to 63 output current deviation signals Δ11 to Δ
■Threshold signal Sl whose level rises and falls according to the proportional portion and cumulative portion of 4, 92. S3. S4 is output to PWM circuits 70-73. Then, the PWM circuits 70 to 73 receive the dark value signals 81 to S4 and the triangular wave S input from the oscillation circuit 80.
Chiyo Npingbarsu Pi, P2. P3
．． Create P4. This Chiyo, Tsubingbals P1~P
The duty ratio of 4 is determined by the magnitude of the dark value signals 81 to S4. In other words, the duty is adjusted so that the actual current is fed back and the deviation between the current command and the actual current becomes zero.
The ratio is adjusted. And Chiyo Npingbarsu P1~
P4 is the drive control block 1 from each PWM circuit 70 to 73
2 is output.

The drive control block 12 includes phase drive sections 90.91, 92.93 provided for each phase, a DC power supply 94, and a regeneration capacitor 95. Each phase drive section 90~
93 is the phase winding L of the SR motor SRM from the DC power supply 94.
Two transistors T r that control energization to 1 to L4
a, T rb and each transistor Tra,
Current regeneration diodes Da and Db that protect Trb;
The drive circuit Dr that drives the transistors Tra, T'b
a, Drb, and a well-known current sensor CT that detects the current flowing through the phase windings L1 to L4.

The above chopping pulses PI to P4 are used in the drive circuit Dr.
a, D When input to rb, transistor Tra
.

The conduction timing of Trb is controlled, and the current command signal 5et1.
I 5et2. I 5et3. I 5et
Currents corresponding to 4 ■1, I2. I3. I4 is supplied from DC power supply 94 to phase windings L1 to L4.

Note that the current control block 10 and the drive control block 12 correspond to energization control means.

As shown in FIG. 3(A), when accelerating, a current 11 corresponding to the current value data is applied to each phase winding L1 to L4.
~■4 flows and positive torque T1. from each phase magnetic pole. T2. T
3. T4 is applied to the rotor, and as shown in FIG. 3(B), when decelerating, currents II, 12 . I3 I4 flows (the rotor rotation angle at the start of energization is smaller than the electrical angle π when accelerating)
(the current waveform is laterally symmetrical with respect to the case of acceleration when centered around electrical angle π), and negative torques TI, T2 . T3. T4 is applied to the rotor. In this way, a positive or negative torque of the target magnitude is generated in the SR motor, and the rotational speed of the SR motor SRM is quickly controlled to the target rotational speed.

In the case of reverse rotation operation, current value data for negative torque generation is used when accelerating, and current value data for positive torque generation is used when decelerating.

As described above, the variable reluctance motor rotation control device 1 of this embodiment corrects the current value data using correction data created based on the nonlinear static characteristics of the phase winding current and the generated torque. Since the energization to L4 is controlled, the commanded target torque is generated. Therefore, S.R.
The rotational speed of motor SRM is quickly controlled to the target rotational speed.

Furthermore, conventionally, energization is controlled so that the current supplied to the phase winding during the energization period is averaged to a predetermined magnitude, so the generated torque fluctuates. However, in this embodiment, the phase winding type is very close to the nonlinear correlation characteristic between the phase winding current and the generated torque that the SR motor has. Although the current control block 10 and the current control block 10 are made up of analog elements, they can also be made up of digital elements. Furthermore, by adding a logic operation circuit, it is possible to execute a current command by executing a control program and to correct current value data using a microprocessor. In this case, the configuration of each of the circuits described above can be simplified. Therefore, the rotation control device 1 for the SR motor SRM can be downsized.

In addition, the temperature characteristics of the device 1 can be improved.

Further, in the above embodiment, the correction data is stored in the read-only memory 24, and the current value data for standard torque generation is corrected according to the magnitude of the target torque. A correction value signal corresponding to the magnitude of the target torque may be generated using a function generator. In this case, the A/D converter 22 and the D/A converter 25 can be omitted.

[Effects of the Invention] As explained above, according to the present invention, the phase winding current value is corrected by the correction value created based on the static characteristics of the phase winding current and the generated torque. Since the energization of the SR motor is controlled, the rotational speed of the SR motor is quickly controlled to the target rotational speed, and stable operation with less vibration is performed.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a rotation control device for a variable reluctance motor which is an embodiment of the present invention, and FIG. 2 (A) and (
B) is an explanatory diagram showing an example of current value data, FIG. 3(A)
is an explanatory diagram showing the phase winding current and generated torque during acceleration, Figure 3 (B) is the same explanatory diagram during deceleration, and Figure 4 is the electrical angle and generated torque when a constant current is supplied to the phase winding. FIG. 5 is an explanatory diagram showing the correlation characteristics with torque. FIG. 5 is an explanatory diagram showing the static characteristics of the phase winding current and the generated torque with respect to the rotor angle of the SR motor at which the generated torque is maximum. 1... Rotation control device for variable reluctance motor 2...
・Shaft encoder 4...F/V converter 6・
...Torque command block 8...Current command block 1
0...Current control block \12...
Drive control block 22...A/D converter 23...Address interface 24...Read-only memory (ROM) 25...D/
A converter 30-33...Read-only memory (ROM) 40-4
3...D/A converter L1-L4...Phase winding SRM...Variable reluctance motor agent Patent attorney Tsutomu Sadate (and 2 others) Figure 2 (A) CB) Le Ling electrical angle 27c/ Figure 4 Figure 5

Claims (1)

[Claims] A rotation angle detection means (2) for detecting a rotation angle of a rotor of a variable reluctance motor (SRM), and a rotation angle of the rotor when the variable reluctance motor (SRM) generates a reference torque. Storage means (30, 31, 32, 33) that stores the corresponding phase winding current values in advance; Correction value generating means (22, 24
, 25) and the storage means (30, 31, 32, 33)
a correction means for reading out a phase winding current value corresponding to the rotation angle of the rotor, and correcting the phase winding current based on a correction value corresponding to the target torque generated from the correction value generation means (
23, 25, 40, 41, 42, 43) and the phase windings (L1, L2, L3,
energization control means (10, 12) for controlling energization to L4);
), and a rotation control device for a variable reluctance motor.