JP2000092885A - Dc motor control circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accelerate the feedback control of a DC motor control circuit with a small-scale circuit. SOLUTION: This control circuit is provided with a position determining means 121 which outputs a coincidence signal in the case where matching exists as a result of detecting changes in position signals of respective phases by a feedback part 12, keeping the position signals of respective phases synchronously with the changes in position signals, and comparatively determining changing patterns for matching; a shift register means 122 which, with permission patterns and changing patterns preset, rotatingly shifts them for parallel outputting by the coincidence signal; and a delay timer means 123 which, with a delay time preset so as to be delayed by 60 degrees in response to the rotor speed of a DC motor, starts by the coincidence signal and outputs a delay signal upon time-out. A PWM output timer part 13 inputs each of the delay signal and the AND signal of the permission pattern and the delay signal as a control signal for buffer updating and timer restart.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a DC motor control circuit, and more particularly to a DC motor control circuit that controls and outputs a PWM output for driving each phase of an armature winding by feeding back position information of a rotor.

[0002]

2. Description of the Related Art In recent years, quietness has been mainly cited as a performance required of a DC motor. In order to improve the quietness, it is necessary to improve the rotation efficiency and rotation accuracy of the motor, and therefore, attention has been paid to the feedback control of the DC motor. In this feedback control, a PWM-controlled inverter output is sent to each phase of an armature winding of a DC motor by a PWM method to generate torque, rotate the rotor, and detect an induced voltage due to the rotation of the rotor. In this method, the position information of the rotor is fed back to control the PWM output to each phase of the armature winding.

FIG. 3 is a timing chart showing input / output signals of a DC motor in which the feedback control is performed.
PWM outputs U, V, W and synchronization signals / U, / V, / W
Are input signals of the DC motor. PWM output U, V, W
Is a signal for energizing each phase of the armature winding of the DC motor by 120 degrees. Synchronization signals / U, / V, / W are signals shifted 180 degrees in synchronization with the PWM outputs U, V, W, respectively. It is. Further, the position signals u, v, w are output signals of the DC motor, the position information of the rotor detected from the rotor position of the DC motor, respectively, and each armature winding U,
120 ° and 60 ° before V and W are respectively shown.

Conventionally, these position signals u, v, w are fed back to control and output PWM outputs U, V, W.
As the C motor control circuit, a microcomputer having built-in inverter control hardware has been used.

[0005] For example, FIG. 4 is a block diagram showing this conventional DC motor control circuit. Referring to FIG.
This conventional DC motor control circuit includes a data processing unit 11, a change detection unit 14, a delay timer unit 15, a PWM output timer unit 16 built in a microcomputer.
And drives the DC motor 20 in a controlled manner.

The change detector 14 receives position signals u, v, w from the DC motor 20, and receives these position signals u, v, w.
, An external interrupt is issued to the process being executed by the data processing unit 11 and the software process 111 is started. Here, since the change of the position signals u, v, w occurs every 60 degrees, an external interrupt also occurs every 60 degrees.

[0007] The delay timer unit 15 is used for software processing 1
11 is set or controlled to start, and the position signals u,
A delay time delayed by 60 degrees according to the rotation speed from the detection of the change of v and w to the detection of the next change is corrected by the software processing time, set and activated, a timer interrupt is performed by timeout, and the software processing 112 is activated.

The PWM output timer unit 16 includes a buffer and a timer in which the next data for the PWM outputs U, V, and W are set in advance. The buffer update or the timer restart is performed by the software processing 112, and the armature windings are reset. The PWM outputs U, V, and W for energizing each phase by 120 degrees are controlled and output.

The data processing unit 11 includes a CPU, a memory, and the like, performs data processing according to an installed program, and executes various software processes. Here, software processing 111 for executing rotor position detection control in order to perform feedback control of the DC motor 20 is performed.
Only 112 is shown. Further, the change detection unit 14, the delay timer unit 15, the PW
Initial setting or change setting of the M output timer unit 16 is performed as necessary.

The software processing 111 includes the change detecting unit 1
4 is interrupted and started by the data processing unit 11 due to an external interrupt generated each time the position signal u, v, w changes. This processing checks the position signals u, v, w and controls the delay timer unit 15 every 60 degrees at which the position signals u, v, w change. The software process 112 is started by interrupting the process being executed by the data processing unit 11 by the timer interrupt generated by the delay timer unit 15. In this process, the buffer or timer of the PWM output timer unit 16 is controlled by a timer interrupt, and the buffer is updated or the timer is restarted.

Next, a processing example of the data processing unit 11 will be briefly described with reference to the drawings. FIG. 5 is a flowchart showing a processing example of the software processing 111 described above.

First, an external interrupt is generated every time the position signals u, v, w are changed. In a processing step 61, the changed position signals u, v, w are held, and in a processing step 62, they are stored in advance as table data. The change pattern of the stored position signals u, v, w is read out, and in processing step 63, the held position signals u, v, w are compared with the change pattern and checked. Exit if no match,
If they match, proceed to processing step 64. Processing step 64
, It is checked whether the operation of the delay timer unit 15 is completed. Normally, the operation is completed, and in this case, processing step 6
6; if in operation, proceed to processing step 65; In processing step 65, abnormal processing such as stopping the delay timer section 15 and setting change of the PWM output timer section 16 is performed, and the process proceeds to processing step 66.

In processing steps 66 and 67,
The delay time, which is delayed by 60 degrees according to the rotation speed from the detection of the change of the position signals u, v, w to the next change, is corrected and calculated by the software processing time, set in the delay timer unit 15, and started.

[0014]

In this conventional DC motor control circuit, there has always been a problem that the speed of the feedback control of the DC motor rotation cannot be increased.

The reason is that this feedback control processing must be interrupted with the highest priority, and the time required for this interrupt processing is 2% of the total available time.
This is because the rotation speed is about 0%, and the software load increases as the rotation speed increases. For example, in the case of a motor used in an air conditioner, the rotation speed is from 20 Hz to 300 Hz.
Hz, and it is necessary to divide one rotation into six and perform feedback control every 60 degrees. Although there is no problem at low speed rotation, for example, at 300 Hz high speed rotation,
A feedback control process for every 500 us is required. For example, if a microcomputer uPD78362A manufactured by our company with a minimum instruction execution time of 0.625 us is used, a time of about 100 us is required for this feedback control process.

Although the feedback control process can be speeded up by using hardware, a new problem that the circuit scale for the feedback control is increased also occurs.

Accordingly, an object of the present invention is to increase the speed by performing the feedback control of the DC motor control circuit with a minimum-scale circuit.

[0018]

Therefore, the present invention provides a D
The C motor inputs the position signals of the respective phases detected from the rotor position as signals indicating 120 degrees when the armature windings are energized and 60 degrees before the energization, respectively, and for each change in the position signals of these phases, It is determined whether or not each of them matches a preset change pattern, and each phase of the armature winding is set to 12
A DC motor control circuit that controls and outputs a PWM output that is energized by 0 degrees includes a buffer and a timer in which the next data for the PWM output is set in advance. A PWM output timer unit for controlling and outputting
A permission pattern for permitting the timer restart in association with the change pattern is set in advance, and for each change in the position signal of each phase, a match signal is output by determining whether the change pattern matches the change pattern, A feedback unit that feedback-outputs the control signal to the PWM output timer unit in accordance with the delay signal obtained by delaying the coincidence signal and the permission pattern.

The feedback section detects a change in the position signal of each phase, holds the position signal of each phase in synchronization with the change of the position signal, compares the change with the change pattern, and determines whether the pattern matches. And a position judging means for outputting the coincidence signal.

Further, the feedback unit includes a shift register means in which the permission pattern and the change pattern are set in advance, and the permission pattern and the change pattern are rotationally shifted by the coincidence signal and output in parallel.

Further, the feedback unit is configured to control the DC
Delay time means for delaying by 60 degrees in accordance with the rotor speed of the motor is set in advance, and is provided with a delay timer means which is activated by the coincidence signal and outputs the delay signal upon timeout.

Further, the PWM output timer section inputs the delay signal, the logical product signal of the permission pattern and the delay signal as the control signal, and performs the buffer update and the timer restart, respectively. ing.

Further, it is built in the microcomputer, and is initially set or changed by the data processing unit.

[0024]

Next, the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the DC motor control circuit of the present invention.

Referring to FIG. 1, a DC motor control circuit according to this embodiment includes a data processing unit 11, a feedback unit 12, a P
The WM output timer section 13 controls and drives the DC motor 20.

The data processing unit 11 includes a CPU, a memory, and the like, performs data processing according to an installed program, and executes various software processes, similarly to the conventional circuit block shown in FIG. In the present embodiment, D
Initial setting or change setting of the feedback unit 12 and the PWM output timer unit 13 for performing feedback control of the C motor 20 are performed as necessary.

The PWM output timer section 13 includes a buffer and a timer in which the next data for the PWM outputs U, V, and W are set in advance, similarly to the conventional circuit block shown in FIG. In the present embodiment, the buffer update or the timer restart for these buffers or timers is
PWM outputs U, V, which are performed by a control signal from the feedback unit 12 and energize each phase of the armature winding by 120 degrees.
W is controlled and output.

The feedback section 12 further includes a position judging means 121, a shift register means 122, a delay timer means 123, and an AND gate 124. The position signals of each phase are input, and the position signals u, For each change in v and w, it is determined whether the change pattern matches a preset change pattern, and a control signal for controlling the buffer update of the buffer or the timer of the output timer unit 13 or the restart of the timer is output.

The position judging means 121 detects a change of the position signal of each phase, holds the position signal of each phase in synchronization with the change of the position signal, and compares and judges with the change pattern of the shift register means 122. In the case of a match, a match signal is output. The position determining means 121 can be constituted by a known change detection circuit, holding circuit, and comparison circuit.

In the shift register means 122, a permission pattern and a change pattern for permitting the restart of the timer in association with the change pattern are set in advance by the data processing unit 11. And output in parallel. FIG. 2 shows a permission pattern and a change pattern preset in the shift register means 122 and the position signal u,
It is explanatory drawing explaining the relationship between v and w. Here, an example of a permission pattern in which the high level changes simultaneously with each high level change of the change patterns of the position signals u, v, w is shown.

The delay timer means 123 is set in advance by the data processing section 11 to have a delay time of delaying 60 degrees in accordance with the rotor speed of the DC motor. And outputs a delayed signal.

The AND gate 124 outputs a control signal for controlling restart of the timer of the PWM output timer unit 13 based on the permission pattern and the delay signal of the shift register means 122 and the delay timer means 123.

Next, the operation of the DC motor control circuit according to the present embodiment will be briefly described with reference to FIGS.

First, as shown in FIG. 2, the permission pattern and the change pattern are preset in the shift register means 122 by the data processing unit 11, and the delay time delayed by 60 degrees according to the rotor speed of the DC motor is set as the data. It is set in advance by the processing unit 11.

Next, as shown in FIG. 3, the rotor of the DC motor 2 is rotated by the PWM outputs U, V, W, and the position signals u, v of each phase, which are rotation position information of the rotor. ,
w is output from the DC motor 2. The position signals u, v, w of each phase are inputted to the position judging means 121 to detect a change of the position signal of each phase, and the position signal of each phase is held in synchronization with the change of the position signal, and the shift register Means 1
The change patterns are compared with each other, and in the case of a match, a match signal is output.

According to this coincidence signal, the permission pattern and the change pattern stored in the shift register means 122 are rotationally shifted and output in parallel, and the delay timer means 123 is started. After the elapse of the delay time set in the delay timer means 123, a delay signal is output due to a timeout, and the PWM output timer unit 13 receives the buffer update as a control signal. Further, a control signal for controlling the restart of the timer of the PWM output timer unit 13 is output from the AND gate 124 based on the delay signal and the permission pattern of the shift register unit 122.

With the input of these control signals, the PWM outputs U, V and W of the PWM output timer section 13 are feedback-controlled.

As described above, in the DC motor control circuit of the present invention, the feedback control from the position signal change to the next change does not include software processing by the data processing unit, and is compared with the conventional DC motor control circuit. Speed up. Although a shift register means is added to the conventional circuit, the data processing unit does not need a memory area for storing a program and a table necessary for the corresponding software processing. It is suppressed as a whole, and the circuit of the feedback unit can be realized by a circuit of the minimum scale.

[0039]

As described above, the DC according to the present invention is
The motor control circuit includes a shift register means in the feedback unit, sets a change pattern of the position signal of each phase and a permission pattern for permitting the timer restart in advance, and matches the position signal and the change pattern of each phase. By performing the rotation shift by the signal and performing the parallel output, there is an effect that the feedback control from the change of the position signal to the next change can be speeded up by a circuit of a minimum scale.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an embodiment of a DC motor control circuit according to the present invention.

FIG. 2 is an explanatory diagram illustrating a relationship between a permission signal and a change pattern preset in a shift register unit of FIG. 1 and a position signal;

FIG. 3 is a timing chart showing input / output signals of a DC motor.

FIG. 4 is a block diagram showing a conventional DC motor control circuit.

FIG. 5 is a flowchart showing a processing example of software processing 111 in the DC motor control circuit of FIG. 4;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Data processing part 111,112 Software processing 12 Feedback part 121 Position determination means 122 Shift register means 123 Delay timer means 13,16 PWM output timer part 14 Change detection part 15 Delay timer part 20 DC motor 61-67 Processing step

Claims (6)

[Claims] When the DC motor is energized by each armature winding,
A position signal of each phase detected from the rotor position is input as a signal indicating 0 degree and 60 degrees before it, respectively,
A DC motor control circuit for controlling the PWM output for energizing each phase of the armature winding by 120 degrees for each phase signal change of each phase to judge whether it matches the preset change pattern. A PWM for controlling and outputting the PWM output by providing a buffer and a timer in which the next data for the PWM output is set in advance and performing a buffer update or a timer restart by inputting a control signal
An output timer unit and a permission pattern for permitting the restart of the timer in association with the change pattern are set in advance, and for each change in the position signal of each phase, it is determined whether the change pattern matches the change pattern. A DC motor control circuit, comprising: a feedback unit that outputs a signal and feeds back the control signal to the PWM output timer unit in response to a delay signal obtained by delaying the coincidence signal and the permission pattern. 2. The method according to claim 1, wherein the feedback unit detects a change in the position signal of each phase, holds the position signal of each phase in synchronization with the change of the position signal, compares the change with the change pattern, and determines a match. 2. The DC motor control circuit according to claim 1, further comprising a position determination unit that outputs the coincidence signal. 3. The feedback unit includes a shift register means in which the permission pattern and the change pattern are set in advance, and the permission pattern and the change pattern are rotationally shifted by the coincidence signal and output in parallel.
The DC motor control circuit according to claim 1. 4. The feedback unit includes delay timer means for setting a delay time for delaying 60 degrees according to the rotor speed of the DC motor in advance, starting by the coincidence signal, and outputting the delay signal by timeout. The DC motor control circuit according to claim 1, 2 or 3. 5. The PWM output timer section inputs the delay signal, the AND signal of the permission pattern and the delay signal as the control signal, and performs the buffer update and the timer restart, respectively. , Claim 1
A DC motor control circuit as described. 6. The DC motor control circuit according to claim 1, wherein the DC motor control circuit is built in a microcomputer and is initially set or changed by a data processing unit.