JPH07231693A - Driver of motor - Google Patents

Abstract

PURPOSE:To prevent the noise from a motor by switching on or off the switch elements which supplies the coil of a motor with driving power in ON periods different from each other in continuous cycles. CONSTITUTION:A driver 1 has a speed command part 9 which generates a speed command corresponding to the predetermined reference rotational speed of a motor 2, and a rotation cycle signal, a detection signal h1, h2, and h3, and a speed command are inputted into a sine wave generating circuit 10. The sine wave generating circuit 10 generates a control signal of three-phase roughly sine waves having phase differences of 120 deg. from each other, from the positional information of the rotor 19 gotten at every 60 deg. of electric angle by the rotation period detection signals h1, h2, and h3 and the speed command. At this time, three-phase sine wave generating circuit 10 generates such sine waves that the switch-on start time of a V-phase control signal and that of a W-phase signal are separated by time t2 from each other, as against that the switch-on start time of a U-phase control signal and that of a V-phase control signal are separated by time t1 from each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor drive device.

[0002]

2. Description of the Related Art Conventionally, in the field of driving automatic doors, for example, a three-phase DC brushless motor (hereinafter referred to as
(Abbreviated as a motor) is used. In such a motor, a stator is provided with 3n coils, for example, 6 coils, and as a rotor, a north pole and a south pole are alternately magnetized in the circumferential direction, and as an example, a permanent magnet having two magnetic poles is used. It is used. Further, this motor is provided with three Hall elements to detect the rotation speed of the motor. Further, an inverter circuit including a transistor that supplies driving power to each coil is used. The detection output from the Hall element is input to a control circuit, and the control circuit, based on the detection output and a predetermined rotation speed, so that the rotation speed of the motor matches the predetermined rotation speed, An amplitude-modulated pulse signal is generated to turn on / off the transistor of the inverter circuit.

FIG. 3 is a waveform diagram showing a conventional driving method. Conventionally, the transistors of each stage corresponding to the coils of each phase of the motor are controlled to be turned on and off in the same conducting period for each of them, as shown in FIG. 3 (1). Even when the motor used is a single phase, as shown in FIG. 3 (2), conduction and interruption are controlled in the same conduction period in two consecutive cycles.

[0004]

In the conventional driving method, in the case of the three-phase driving shown in FIG. 3 (1), the transistors are turned on six times while the three-phase driving signals all pass one cycle. Therefore, a resonance sound having a frequency of 6f is generated with respect to the driving frequency f. Further, in the case of the single-phase drive shown in FIG. 3 (2), similarly, the resonance sound of the frequency 2f is generated for the drive frequency f. It is desired to prevent the generation of such resonance noise.

An object of the present invention is to solve the above-mentioned technical problems and to provide a motor drive device capable of preventing noise from being generated from the motor.

[0006]

In a motor drive device of the present invention, a switch element for supplying drive power to a coil of a motor and a switch element are respectively provided in consecutive periods in mutually different conduction periods. It is provided with a control means for controlling conduction and interruption, by which the above-mentioned object can be achieved.

In the present invention, the coil may be selected as a single phase.

The motor drive device of the present invention comprises a plurality of switch elements for supplying drive power to coils for each phase of a motor having coils of a plurality of phases, and a switch at each stage corresponding to each coil. The device is provided with a control means for controlling conduction and interruption during conduction periods different from each other, whereby the above object can be achieved.

In the present invention, the plurality of phases may be selected as three phases.

[0010]

According to the present invention, the motor is rotationally driven by supplying driving power to the coil through the switch element. At this time, the control means controls conduction and interruption of the switch element in consecutive conduction periods which are different from each other in consecutive cycles. As a result, the timing at which the switch element is turned on is sequentially shifted in each cycle, so that resonance noise having a frequency that is an integral multiple of the drive frequency is prevented from being generated.

Further, in the present invention, the motor is rotationally driven by supplying drive electric power to the coils of a plurality of phases via the switch elements of a plurality of stages. At this time, the control means controls conduction and interruption of the switch elements of each stage in conduction periods different from each other. As a result, the timings at which the switch elements of the respective stages are turned on are different from each other between the phases, so that resonance noise having a frequency that is an integral multiple of the drive frequency is prevented from being generated.

[0012]

1 is a circuit diagram showing the electrical construction of a motor drive unit 1 according to an embodiment of the present invention, and FIG. 2 is a time chart showing the operation of the drive unit 1 according to the present embodiment. In this embodiment, a three-phase motor will be described as an example.
The motor drive circuit of the present invention is not limited to this example. The motor 2 of this embodiment has, for example, three phases,
A stator 20 having three coils 3, 4, and 5 is provided, and each pair of coils 3, 4, and 5 is driven by the U-phase, V-phase, and W-phase drive signals from the drive device 1. In this embodiment, three magnetic pole detection elements H, which are, for example, Hall elements, are provided facing the coils 3, 4, and 5, and the coils 3, 4, and 5 are provided.
The magnetic flux density is detected and the detection signals h1, h2, h3 are output. The motor 2 also includes a rotor 19 made of a permanent magnet or the like having a pair of magnetic poles.

In the driving device 1, the coils 3, 4 and 5 are provided with the U
An inverter circuit 6 for supplying drive signals of phase, V phase, and W phase, respectively, is provided, and the inverter circuit 6 is provided with six transistors Q1, Q2, Q3, Q4, Q5, Q6. The transistors Q1 and Q4 are connected to the DC power supply 7. Transistors Q1, Q4; Q2, Q5; Q3, Q6
The U-phase, W-phase, and V-phase drive signals are taken out from the respective connection points.

A driving device 1 for inputting a driving control signal to the bases of the transistors Q1, Q2 and Q3 is provided. The drive device 1 is configured as an integrated circuit element, and is provided with a rotation pulse detection circuit 8 that detects the rotation speed or rotation cycle of the motor 2 from the magnetic flux detection signal output from the magnetic pole detection element H. The drive device 1 includes a speed command unit 9 that generates a speed command input corresponding to a predetermined reference rotation speed of the motor 2, and includes a rotation cycle signal and detection signals h1, h.
2, h3 and the speed command input are input to the sine wave generation circuit 10.

As an example, the sine wave generating circuit 10 is shown in FIG. 2 (1) based on the rotation period, the position information of the rotor 19 and the speed command input obtained at every 60 electrical degrees by the detection signals h1, h2 and h3. 3), a three-phase substantially sinusoidal control signal having a phase difference of 120 degrees from each other is generated. At this time, in the three-phase sine wave generation circuit 10, as an example, as shown in FIG. 2A, the conduction start times of the U-phase control signal and the V-phase control signal are separated from each other by time t1. On the other hand, the conduction start times of the V-phase control signal and the W-phase control signal are selected so as to be separated from each other by time t2. Also,
The time t1 and the time t2 are selected to have mutually different lengths.

As described above, according to the present embodiment, the timings at which the switch elements Q1 to Q6 at the respective stages are turned on are different from each other between the phases, so that the drive frequency f as described in the section of the prior art is used. Resonance noise having an integral multiple of frequency is prevented from being generated.

As another embodiment of the present invention, when the motor 2 is a single-phase motor, the three-phase sine wave generating circuit 10 is a single-phase motor as shown in FIG. A control signal having a substantially sinusoidal shape is generated. At this time, the three-phase sine wave generation circuit 10 is, for example, as shown in FIG. 2B, the control period t11 of the positive period and the control period t12 of the negative period.
And are chosen to have different lengths. As a result, the timing of conduction of each switch element is sequentially shifted in the adjacent positive period and negative period, so that resonance noise having a frequency that is an integral multiple of the drive frequency is prevented from being generated.

In the above embodiments, the case where the coil has three phases has been described as an example of a plurality of phases, but the present invention is not limited to this example.

Further, in the present invention, the signal processing may be performed by software processing by a microcomputer or the like.

[0020]

As described above, according to the present invention, when the motor has a single phase, the control means controls the switching element to conduct and cut off in different conduction periods in consecutive cycles. To do. As a result, the timing at which the switch element is turned on is sequentially shifted in each cycle, so that resonance noise having a frequency that is an integral multiple of the drive frequency is prevented from being generated.

Further, in the present invention, when the motor has a plurality of phases, the control means controls conduction and interruption of the switch elements of each stage in mutually different conduction periods. As a result, the timings at which the switch elements of the respective stages are turned on are different from each other between the phases, so that resonance noise having a frequency that is an integral multiple of the drive frequency is prevented from being generated.

[Brief description of drawings]

FIG. 1 is a block diagram of a drive device 1 according to an embodiment of the present invention.

FIG. 2 is a time chart explaining the operation of the driving device 1 of the present embodiment.

FIG. 3 is a time chart for explaining the problems of the conventional example.

[Explanation of symbols]

 1 Drive Device 2 Motor 3, 4, 5 Coil 6 Inverter Circuit H Magnetic Pole Detection Element 10 Sine Wave Generation Circuit 11, 12, 13 Pulse Width Modulation Circuit Q1, Q2, Q3, Q4, Q5, Q6 Transistor

Claims (4)

[Claims] 1. A motor drive comprising: a switch element for supplying drive power to a coil of the motor; and a control means for controlling conduction and interruption of the switch element in respective consecutive periods which are different from each other in a continuous cycle. apparatus. 2. The motor driving device according to claim 1, wherein the coil is selected as a single phase. 3. A plurality of switch elements that respectively supply drive power to the coils for each phase of a motor having a plurality of phase coils, and switch elements of each stage corresponding to the coils of each other are made to have mutually different conduction. A drive device for a motor, comprising: a control unit that controls conduction and cutoff during a period. 4. The motor drive device according to claim 3, wherein the plurality of phases are selected from three phases.