JPH0287996A - Rotation controller for variable reluctance motor - Google Patents

Abstract

PURPOSE:To control the speed of a motor quickly and stably to a target speed by controlling the phase winding current corresponding to the non-linear correlative characteristic of the phase winding current and torque of a variable reluctance motor. CONSTITUTION:A means 2 for detecting the rotary angle of the rotor of a variable reluctance motor(SRM) is provided. A phase winding current value corresponding to the rotary angle of the rotor detected through the rotary angle detecting means 2 and an externally provided target torque is read out, through a read-out means 23, from memory means 30, 31, 32, 33 where the relation between the torque, the rotary angle of the rotor and the phase winding current of the SRM is stored previously. Means 10, 12 for controlling conduction of power to the phase windings L1, L2, L3, L4 of the SRM based on the phase winding current value detected through the read-out means 23 is also provided. Since power conduction for the phase windings is controlled according to the phase winding current value prepared based on the non-linear correlative characteristic of the phase winding current required for production of predetermined torque and the rotary angle of the rotor, target torque can be produced.

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 SR motor), the average current flowing through the phase windings is controlled to a predetermined magnitude, and the SR motor is controlled at a target rotation speed. By controlling the average current to increase or decrease in proportion to the amount of torque required to operate at
A device is known that controls the rotational speed of an SR motor to a target 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. Ii
As shown in the following equation, the characteristic is the product of the square of the phase winding current and the rate of change of the phase winding inductance,
Moreover, the inductance changes depending on the phase winding current.

T = k
is the rotation angle of the SR motor) That is, 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, 1. the above-mentioned rotation control device has the problem that 1. so-called torque ripple occurs during operation of the SR motor, making the rotation 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 SR 1,000 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 generated torque increases approximately quadratically with respect to the increase in current, and eventually increases approximately quadratically. If the current further increases, the stator magnetic poles of the SR motor become magnetically saturated, so even if the current increases, the generated torque will hardly increase.

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. Special’
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 toruia changes approximately quadratically with respect to changes in the phase winding current. Simply increasing or decreasing the phase winding current will greatly fluctuate the generated torque. Therefore, 2. The above-mentioned rotational speed device has the problem that the speed control becomes oscillatory.

Therefore, the present invention aims to control the phase winding current in response to the non-linear correlation characteristic between the phase winding current of the SR motor and the generated torque.
The object of this invention is to provide a rotation control device for a variable reluctance motor that quickly and stably controls the rotation of a variable reluctance motor.

[Means for Solving the Problems] The gist of the present invention is to provide a rotary angle detection means for detecting a rotation angle of a boater of a variable reluctance motor;
- storage means in which the relationship between the torque of the variable reluctance motor, the rotation angle of the rotor, and the phase winding current value is stored in advance;
reading means for reading out, from the storage means, a phase winding current value corresponding to the rotation angle of the rotor detected by the rotation angle detection means and the g-torque inputted from the outside; and energization control means for controlling energization to the phase windings of the variable reluctance motor based on the phase winding current values determined.

[Function] According to the above configuration of the present invention, when the rotation angle means detects the rotor rotation angle of the variable reluctance motor, the phase winding current value corresponding to the rotation angle of the rotor and the target torque input from the outside is detected. The reading means does not read out from the storage means. Therefore, the energization control means controls energization to the phase windings of the variable reluctance motor based on the successively outputted phase winding current values.

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

As shown in FIG. 1, the variable reluctance motor rotation control device 1 includes a well-known Schabut encoder 2 as rotation angle detection means, a well-known F/V converter 4,
It is composed of a torque command block 6, a current command block 8, etc., a current control block 10, and a drive control block 12. road)
A closed-loop control system is formed to control the target speed input from the target speed.

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 an 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 non-proportional amount proportional to the speed deviation and the cumulative amount 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, a target torque command signal T is input to a well-known A/D converter 22. 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 digital signal Td and the rotation angle detection signal θ are inputted to the address interface chair 23 as a reading means.

The address interface 23 is composed of a well-known logic element, an amplifier down counter, etc., and is based on the digital signal Td and the rotation angle signal θ, and uses a continuous read only memory (hereinafter referred to as ROM) 30, 31 as a storage means, 32
．． An address signal that specifies the address within 33 is created. That is, the address interface 23 specifies a predetermined area in the ROMs 30 to 33 based on the digital signal Td, specifies an address within the area based on the rotation angle signal θ, and sends the address signals At, A2 . A3. Create A4. For example, in the case of a four-phase (8-pole stator, 6-pole rotor) SR motor SRM, each phase winding L1, L2 . L3. L
Four address signals A1 to A4 are created so that the phase of the current flowing in ROM3 is shifted by 90 degrees in electrical angle, and
Output to 0-33.

The same digitized current (direct data) is stored in these ROMs 30 to 33. This current value data shows the phase winding current required to generate a predetermined torque using the electrical angle as a parameter. is set,
Generally called a current pattern. The current value data is
Current value data for positive and negative torque generation is created for each predetermined torque unit, and is stored in a predetermined area of each of the ROMs 30-33. This current f+i data is
Nonlinear correlation characteristics between phase winding current and rotor rotation angle when generating a certain amount of torque (shown in Figure 4)
Created based on. For example, for each predetermined torque unit, the waveform of the phase winding current that generates the torque is measured by actual measurement or simulation, and it is created based on this current waveform. An example is shown in FIG. Figure 2 (
A) is the waveform of the phase winding current when positive torque is generated, the second
Figure (B) shows the same waveform when negative torque is generated.

This ROM30-33 has an address interface 23.
When address signals A1 to A4 are input from , the current value is read out from the current value data stored in a predetermined area, and the current value data 1d1°Id2 . Id3.
Id4 is output to D/A converters 40, 41°42.43. The D/A converters 40 to 43 sequentially output current 1-direction data Idl, Id2°Id3. I
Current command signal I5etl, I5 corresponding to d4
et2. I set, 3. I set, 4 is output to the current control block 10.

The current control block 10 includes current comparators 5o, 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 excavation circuit 80 that outputs a triangular wave Sw to the pwM circuits 70 to 73. Note that the current control block 10 corresponds to energization control means.

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~l5et, 4, and a detection signal (voltage signal) of the phase winding current (actual current) input from the current detector CT, which will be described later.
Iactl, Iact2. Iact3. I
detects the deviation from aet4 and generates a current deviation signal Δ■1. △I
2. ΔI3°ΔI4 is output to proportional integral calculators 60-63.

The proportional integral calculators 60 to 63 output current deviation signals Δ■1 to Δ
■Threshold signals Sl, S2. 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.
w and the well-known chopping pulse Pi, P2. P3
．． Create P4. This chopping pulse P1 to P4
The duty ratio is determined by the magnitude of the dark value signals 81 to S4. In other words, the actual current is feed-packed and its duty is adjusted so that the deviation between the current command and the actual current becomes zero.
The ratio is adjusted. Then, chopping pulses P1 to P
4 is a drive control block 12 from each PWM circuit 70 to 73
is output to.

The drive control block 12 includes phase drive units 90, 91, 92, and 93 provided for each phase, a DC power source 94, and a capacitor 95. Each phase drive unit 90 to 93 connects the phase windings of the SR motor SRM from a DC power supply 94 to 1 to L.
two transistors T ra that control energization to 4;
T rb, each transistor T ra, T
Current regeneration diodes Da and Db that protect rb and drive circuit D that drives 2° transistors Tra and Trb.
ra, Drb, and a well-known current sensor CT that detects the current flowing through the phase windings [, 1 to L4.

The drive control block 12 also corresponds to the energization control means.

When the above-mentioned signals P1-1]4 are input to the drive circuits Dra and Drb, the transistor T+''a.

The conduction timing of Trb is controlled, and the current command signal ■5etl is output from the central D/A converters 40 to 43.
The current 11~■4 corresponding to ~l5et4 is the DC power supply 9
4 to the phase windings L1 to L4.

Now, as shown in FIG. 3(A), when accelerating, a current II corresponding to the current value data is applied to each phase winding L1 to L4.
, I2.13. I4 flows and each phase magnetic (folding force is positive c7), +L, T1, T2, T3, T4
is applied to the rotor, and as shown in FIG. 3(B), when decelerating, each phase is wound, and currents II, I2 . I3. I4 flows (the rotor rotation angle at the start of energization is delayed by an electrical angle π from that in the case of acceleration, and its current waveform is symmetrical to that in the case of acceleration when centered around the electrical angle π), and each Negative torques Tl, T2, T3 . from the phase magnetic poles. T4 is applied to the rotor.

In this way, a positive or negative torque T 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, in the variable reluctance motor rotation control device 1 of this embodiment, the phase winding is Since the energization to the lines L1 to [, 4 is controlled, the commanded target torque is generated. Therefore, the rotational speed of the SR motor SRM is quickly controlled to the target rotational speed.

Furthermore, in this embodiment, since the phase winding current is controlled for each rotor angle, torque fluctuations that occur when operating an SR motor using a conventional rotation control device do not occur, and torque ripple, vibration, resonance, etc. suppressed.

In the second embodiment, the F/V converter 4, the speed comparator 20, the proportional-integral calculator 21, and the current control block 10 are composed of analog elements, but they can also be composed of digital elements. be. Furthermore, logic? It is also possible to execute the current command by adding a 51 arithmetic circuit and executing a control program. In this case, the configuration of each of the circuits described above becomes simple, and the rotation control device 1 for the SR motor SRM can be downsized. Additionally, the temperature characteristics of the device 1 are improved.

[Effects of the Invention] As explained above, the present invention provides phase windings created based on the nonlinear correlation characteristics between the phase winding current required to generate a predetermined torque and the rotation angle of the rotor. Since the energization to the phase windings is controlled according to the line current value, torque is generated according to the target torque. Therefore, the rotational speed of the SR motor can be quickly controlled to the target rotational speed, and stable operation with less vibration can be 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 a current (an explanatory diagram showing an example of direct data, Fig. 3 (A
) is an explanatory diagram showing the phase winding current and generated torque during acceleration, Fig. 3 (B) is the same explanatory diagram during deceleration, and Fig. 4 shows the electrical angle and electric angle when a constant current is supplied to the phase winding. FIG. 5 is an explanatory diagram showing the correlation characteristics with the generated 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 wholesale block 23...-Address interface 30-33...ROM Ll-L4...
Phase winding SRM... - Variable reluctance motor representative Patent attorney Tsutomu Sadate (and 2 others) Ushi Figure 2 (A) (B) 10-Gentomi Ma Kita Juba" + l-1- Shi to Figure 4 Figure 5

Claims (1)

[Claims] Rotation angle detection means (2) for detecting the rotation angle of a rotor of a variable reluctance motor (SRM), torque of the variable reluctance motor (SRM), rotation angle of the rotor, and phase winding current value. The storage means (30, 3
1, 32, 33), and from the storage means (30, 31, 32, 33), the rotor rotation angle detected by the rotation angle detection means (2) and the target torque input from the outside correspond to the rotor rotation angle detected by the rotation angle detection means (2). a readout means (23) for reading out a phase winding current value; and a readout means (23) for reading out a phase winding current value; A rotation control device for a variable reluctance motor, comprising: energization control means (10, 12) for controlling energization to L3, L, 4).