JP2000125581A - Method of controlling motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve operational reliability by stopping a motor in a desired mode. SOLUTION: At stopping of the rotation of a motor 2, drive signals Su, Sv, Sw are supplied respectively with a negative-phase differences to a phase difference between the driving signals Su, Sv, Sw in a normal-operation period, to the coils of a plurality of phases of the motor 2, in a negative-phase drive step. The supply of the drive signals Su, Sv, Sw with the negative-phase difference is continued, until the rotational speed of the motor 2 has reached a threshold level corresponding to the predetermined threshold speed of the motor 2. The supply of the negative-phase difference alternating drive signal is stopped in a signal stopping step, when the rotational speed signal has reached the threshold level.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling the rotational state of an alternately driven motor such as a switched reluctance motor.

[0002]

2. Description of the Related Art In various industrial fields, motors which can be alternately driven and bidirectionally rotated, such as a switched reluctance motor (hereinafter abbreviated as a motor), have been used. FIG. 1 is a block diagram showing an electrical configuration of a control device 1 of a three-phase alternating drive type motor 2 having a configuration which is a basis of the present invention. FIG. 2 is a circuit diagram schematically showing an electrical configuration of the control device 1. FIG. 6 is a diagram schematically showing the switched reluctance motor 2, FIG. 7 is a time chart showing the operation of the conventional technology, and FIG. 8 is a graph showing the operation of the conventional technology.

[0003] Hereinafter, the configuration of the motor 2 will be described with reference to FIG. The motor 2 has 3n motors, for example, 6 motors.
The coils 5 a, 5 b, and 5 c are wound around the magnetic pole portions 3, which are diagonally located, respectively, so as to have mutually different polarities when energized. . The rotor 6 of the motor 2 includes the magnetic pole portions 3 of the stator 4.
For example, four magnetic pole portions 7 are formed so as to have a phase different from that of FIG. The rotor 6 is formed of a magnetic material, but no permanent magnet or electromagnet is used. Each of the coils 5a, 5b, 5c of the stator 4 has a switch SW1,
The power supply 8 is connected via SW2 and SW3.

In such a motor 2, when the switches SW1, SW2, and SW3 are sequentially switched, a rotating magnetic field is generated in the stator 4. This rotating magnetic field and the rotor 6
The motor 2 is driven to rotate by the magnetic coupling with the respective magnetic pole portions 7.

Hereinafter, an electrical configuration of a control device 1 having a configuration serving as a basis of the present invention will be described with reference to FIGS. 1 and 2. FIGS. 1, 2 and 6 are referred to in the following description of the related art and also in the description of the embodiments of the invention described later. Each coil 5 of the motor 2
a, 5b, and 5c represent the U phase, V phase, and W
It is driven by the phase drive signals Su, Sv, Sw.

In this conventional example, the coils 5a, 5b, 5c
A magnetic pole detection element 9 composed of, for example, a Hall element is provided to detect a change in the magnetic flux density of the coils 5a, 5b, 5c. Thus, the magnetic pole detection element 9 can detect the rotating magnetic field for each of the coils 5a, 5b, 5c of the stator 4, and outputs a position signal SP corresponding thereto.

[0007] The control device 1 includes the coils 5a, 5b, 5c
And an inverter circuit 10 for supplying the drive signals Su, Sv, Sw, respectively. As shown in FIG. 2, the inverter circuit 10 includes transistors (hereinafter, may be referred to as upper transistors) TrU1 and TrV1 that supply driving currents to the coils 5a, 5b and 5c, respectively.
TrW1 and transistors TrU2, TrV2, and TrW2 into which the current from the coils 5a, 5b, and 5c flows (hereinafter, sometimes referred to as lower transistors) are provided in correspondence with each of the coils 5a, 5b, and 5c.

Here, the transistors TrU1, TrU
U2 constitutes the switch SW1, and the transistor Tr
V1 and TrV2 constitute the switch SW2, and transistors TrW1 and TrW2 constitute the switch SW3.

The power supply 8 is connected in parallel with a smoothing capacitor C1. A rectifying element D1 for preventing backflow is provided between the transistor TrU1 and the coil 5a.
A rectifying element D2 for preventing backflow is provided between the transistor TrU2. A rectifying element D3 for preventing backflow is provided between the transistor TrV1 and the coil 5b, and a rectifying element D4 for preventing backflow is provided between the coil 5b and the transistor TrV2. Transistor Tr
A rectifying element D5 for preventing backflow between W1 and the coil 5c.
Is provided, and a rectifying element D6 for preventing backflow is provided between the coil 5c and the transistor TrW2.

The position signal SP from the magnetic pole detecting element 9
Is input to the waveform synthesizing circuit 11, and the position signal S for each phase is
The P waveform is synthesized and a position / velocity direction signal is output. This makes it possible to determine the phase and cycle of the position signal SP for each phase, as well as the phase difference and the traveling direction of the phase, that is, the rotational position, rotational speed, and rotational direction of the motor 2. The position / speed direction signal from the waveform synthesis circuit 11 is input to a speed control circuit 12 and an arithmetic circuit 13 including a microcomputer and the like.

A speed command signal corresponding to the reference speed is separately input to the arithmetic circuit 13, and a control signal based on the speed command signal is input to the logic circuit 14 together with a signal from the speed control circuit 12. Then, a control signal for turning on / off each transistor of the inverter circuit 10 is generated and output to the inverter circuit 10. A DC power supply is connected to the inverter circuit 10, and a voltage / current from the DC power supply is modulated by the inverter circuit 10 and supplied to the motor 2. The level of the drive current supplied to the motor 2 is input from the inverter circuit 10 to the speed control circuit 12 as a feedback signal. Thus, the motor 2 is controlled to rotate at the reference speed based on the speed command signal.

In the prior art, a process for stopping the rotation of the motor 2 will be described with reference to FIGS. In the normal rotation period shown in FIG. 7, the control device 1 outputs the drive signals Su, Sv, Sw for each phase shown in FIGS. 7 (1) to 7 (3) from the inverter circuit 10 to each coil 5a of the motor 2. ,
5b and 5c. The drive signals Su, S
v and Sw have a phase difference in which the phases are sequentially shifted for each phase, whereby a rotating magnetic field is generated in the stator 4 and the motor 2 is driven to rotate.

Next, during the reverse rotation period shown in FIG.
Drive signals Su, Sv, Sw
The drive signal S having a phase difference opposite to that in the case of the normal rotation period
u, Sv, and Sw are output to the motor 2. This reversal period is set to a predetermined fixed length. When the rotation of the motor 2 is reduced to a predetermined rotation speed during the reverse rotation period, the control device 1 stops outputting the drive signals Su, Sv, Sw. After this, the motor 2 will be
Stop after continuing to rotate. Thus, the rotation of the motor 2 is stopped.

[0014]

In the conventional driving method, as shown in FIG. 8, when the motor 2 is rotating at a relatively low speed, the reverse rotation period is a fixed period.
Depending on the rotation speed and temperature, the motor 2
May decelerate and stop, and an overshoot phenomenon may occur in which reverse rotation is started.

Further, as shown in FIG. 8, when the motor 2 is rotating at a relatively high speed, the reverse rotation period is a fixed period. May not be able to decelerate to a predetermined speed, and even after the reverse rotation period ends and the supply of the drive signals Su, Sv, Sw to the motor 2 is stopped, the motor 2 may continue to rotate for a relatively long time. is there.

Thus, in the prior art, the motor 2
Undesired operation occurs, and the operation reliability is low.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a motor control method in which operation reliability is improved by stopping a motor in a desired manner. That is.

[0018]

According to the motor control method of the present invention, an alternating drive signal is supplied to each of a plurality of phase coils with a predetermined phase difference, and the coils are driven to rotate. This is a control method for stopping the rotation of the motor that is outputting the rotation speed signal, in which an alternating drive signal is output to the coils of a plurality of phases with a phase difference opposite to the phase difference in response to the motor stop instruction. A reverse-phase driving step in which the supply of the rotational speed signal is continued until the rotational speed signal reaches a threshold level corresponding to a predetermined threshold rotational speed of the motor; And stopping the supply of the anti-phase difference alternating drive signal to the coils of the plurality of phases when the signal reaches the level.

[0019]

According to the motor control method of the present invention, the alternating drive signals are supplied to the coils of the plurality of phases with a predetermined phase difference, and the motor is driven to rotate, and the rotation speed detecting means corresponds to the rotation speed of the motor. A rotation speed signal is output, and the rotation speed of the motor is controlled using the rotation speed signal.

When the rotation of the motor is stopped, in the reverse phase driving step, an alternating drive signal is supplied to a plurality of phase coils of the motor with a phase difference opposite to the phase difference in response to the motor stop instruction, The supply of the anti-phase difference alternating drive signal is continued until the rotation speed signal reaches a threshold level corresponding to a predetermined threshold rotation speed of the motor. next,
In the signal stopping step, when the rotation speed signal reaches the threshold level, the supply of the anti-phase difference alternating drive signal to the coils of a plurality of phases is stopped.

At this time, regardless of whether the motor is rotating at a relatively low speed or at a relatively high speed, the reverse phase difference alternating drive is performed until the rotation speed of the motor reaches the threshold level. A signal is provided to the motor.

Therefore, no matter what rotational speed the motor is rotating, the rotational speed of the motor is reduced to the threshold level when the anti-phase difference alternating drive signal is stopped.
Therefore, the problem that the period of the reverse phase drive step is too short or too long with respect to the rotation speed of the motor, and the motor rotates reversely or takes an excessively long time to stop, is solved. As a result, the operational reliability is significantly improved.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a block diagram showing an electrical configuration of a control device 1 of a three-phase alternating drive type motor 2 having a configuration which is a basis of the present invention. FIG. 2 is a circuit diagram schematically showing an electrical configuration of the control device 1. FIG. 3 is a time chart showing the operation of the present embodiment, FIG. 4 is a graph showing the operation of the present embodiment, FIG. 5 is a flowchart showing the operation of the present embodiment, and FIG. FIG. 2 is a diagram schematically illustrating a reluctance motor 2. 1, 2 and 6 have been described in the section of the related art, and a description thereof will not be repeated.

The present embodiment relates to a method for controlling a motor, and the configuration used for the control method includes the configuration of the switched reluctance motor 2 and the configuration of the control device 1 thereof described in the section of the prior art. The description is the same in the description of the related art, and the names and reference numerals described above are used when necessary for the following description.

In this embodiment, the processing of the control device 1 for stopping the rotation of the motor 2 will be described with reference to FIGS. In step a1 of FIG. 5, during the normal rotation period shown in FIG.
The drive signals Su for each phase shown in (1) to (3) of FIG.
Sv and Sw are output to the coils 5a, 5b and 5c of the motor 2, respectively. The drive signals Su, Sv, Sw have a phase difference in which the phases are sequentially shifted for each phase, whereby a rotating magnetic field is generated in the stator 4 and the motor 2
Is driven to rotate.

Next, at step a2 in FIG. 5, the control device 1 determines whether or not a stop signal for stopping the motor 2 has been input, and waits for the stop signal. When it is determined in step a2 that the stop signal has been input, the process proceeds to step a3, and in the reverse rotation period of FIG. 3 which is the reverse rotation drive step, the drive signals Su, Sv , Sw, the driving signals Su, Sv, Sw having a phase difference opposite to that in the normal rotation period are output to the motor 2. This reverse rotation period is a variable period and continues until the rotation speed of the motor 2 decreases to the threshold level shown in FIG. This rotation speed is detected by a known means such as converting a frequency corresponding to the motor rotation speed of the position speed direction signal from the magnetic pole detection element 9 into a voltage and comparing the voltage with a reference voltage corresponding to the threshold level. It is possible.

In step a4 of FIG. 5, it is determined whether the rotation speed voltage corresponding to the rotation speed of the motor 2 has reached the threshold voltage corresponding to the threshold level. If the rotation speed of the motor 2 is reduced until the rotation speed reaches the threshold level in such a reverse rotation period, the control device 1 stops outputting the drive signals Su, Sv, Sw in step a5.

Thereafter, during a stop period shown in FIG. 7 which is a signal stop step, the motor 2 is slightly
Stop after continuing to rotate. Thus, the rotation of the motor 2 is stopped.

In the control method of this embodiment,
As shown in FIG. 4, the rotation speed of the motor 2 reaches the threshold level regardless of whether the motor 2 is rotating at a relatively low speed or the motor 2 is rotating at a relatively high speed. Until the driving signals Su, Sv,
Sw is supplied to the motor 2.

Therefore, no matter what rotational speed the motor 2 is rotating, the drive signals Su, Sv, Sw
Is stopped, the rotation speed of the motor 2 is reduced to the threshold level. Therefore, the problem that the reverse rotation period is excessively short or too long with respect to the rotation speed of the motor 2 and the motor 2 reversely rotates or takes an excessively long time to stop is solved. Operational reliability is significantly improved.

As a modification of the present embodiment, the frequencies and voltages of the drive signals Su, Sv, Sw of the opposite phase difference during the reverse rotation period are changed in accordance with the rotation speed of the motor 2 at the start of the reverse rotation. It may be. By doing so, the period during which the rotation speed of the motor 2 is reduced to the threshold level can be made substantially constant. Since the period until the stop of the motor 2 in the stop period following the reverse rotation period is constant, in this modification, in addition to the operation and effect of the above-described embodiment, the motor 2
, A new operation and effect can be realized in which the period until the stop of the operation can be kept constant.

The present invention is not limited to the above embodiment, but has a wide variety of modifications without departing from the spirit of the present invention.

[0033]

As described above, according to the present invention, when the rotation of the motor is stopped, in the reverse phase driving step, the phase difference is added to the coils of the plurality of phases of the motor in response to the instruction to stop the motor. Alternating drive signals are supplied with opposite phase differences, respectively, and the supply of the opposite phase difference alternating drive signal is continued until the rotation speed signal reaches a threshold level corresponding to a predetermined motor threshold rotation speed. . Next, in a signal stopping step, when the rotation speed signal reaches the threshold level, the supply of the anti-phase difference alternating drive signal to the coils of a plurality of phases is stopped.

At this time, regardless of whether the motor is rotating at a relatively low speed or at a relatively high speed, the reverse phase difference alternating drive is performed until the rotation speed of the motor reaches the threshold level. A signal is provided to the motor.

Therefore, no matter what rotational speed the motor is rotating, the rotational speed of the motor is reduced to the threshold level when the anti-phase difference alternating drive signal is stopped.
Therefore, the problem that the period of the reverse phase drive step is too short or too long with respect to the rotation speed of the motor, and the motor rotates reversely or takes an excessively long time to stop, is solved. As a result, the operational reliability is significantly improved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an electrical configuration of a control device 1 having a configuration serving as a basis of the present invention.

FIG. 2 is a circuit diagram schematically showing an electrical configuration of the control device 1.

FIG. 3 is a time chart illustrating the operation of the present embodiment.

FIG. 4 is a graph showing the operation of the present embodiment.

FIG. 5 shows the operation of the present embodiment.

FIG. 6 is a flowchart schematically showing a switched reluctance motor 2.

FIG. 7 is a time chart showing the operation of the conventional technique.

FIG. 8 is a graph showing the operation of the conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Control apparatus 2 Motor 3, 7 Magnetic pole part 4 Stator 5a, 5b, 5c Coil 6 Rotor 9 Magnetic pole detecting element 10 Inverter circuit 11 Waveform synthesis circuit 12 Speed control circuit 13 Operation circuit 14 Logic circuit SP Position signal SW1, SW2, SW3 switch Su, Sv, Sw drive signal

Claims (1)

[Claims] An alternating drive signal is supplied to each of a plurality of phase coils at a predetermined phase difference, and the plurality of coils are rotationally driven, and a rotational speed detecting means outputs a rotational speed signal corresponding to the rotational speed of the motor. A control method for stopping the motor, wherein an alternating drive signal is supplied to the coils of the plurality of phases with a phase difference opposite to the phase difference in response to a motor stop instruction,
An anti-phase driving step in which the supply of the anti-phase difference alternating drive signal is continued until the rotation speed signal reaches a threshold level corresponding to a predetermined threshold rotation speed of the motor; And stopping the supply of the anti-phase difference alternating drive signal to the coils of the plurality of phases when the motor has reached the control signal.