JP2007020291A - Motor drive controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor drive controller which suppresses noise that is generated in combination between a motor and a load coupled with the motor, without having to add a mechanism for reducing the noise. <P>SOLUTION: This motor drive controller is equipped with an inverter circuit 7 which drives the motor 8, and a control unit 6 which controls the rotational speed of the motor 8. The control unit 6 makes the rotational speed of the motor 8 increase or decrease into sine wave form, centered upon the target rotational speed. It reduces noise that arises when the natural frequency of the load attached to the motor 8 and the natural frequency of the motor 8 itself generated from the control cycle proportionate to the rotational speed of the motor 8 draw close to each other. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a motor drive control device, and more particularly to a motor drive control device that suppresses noise generated between a motor and a load attached to the motor.

Conventionally, when the natural frequency of a load attached to a motor and the vibration frequency of the motor itself generated from a control cycle proportional to the rotational speed of the motor are close to each other, noise has been increased. Conventionally, the rigidity of the natural frequency of the load is mechanically increased so that the natural frequency does not resonate within the rotational speed range of the motor. Further, when the natural frequency of the load cannot be mechanically changed, a mechanism for absorbing vibration corresponding to the frequency of generated noise is provided (for example, see Patent Document 1).
JP-A-4-283383

  However, in the conventional configuration, it is necessary to add a mechanism to reduce noise, and there is a problem that the structure of the device is increased, the weight is increased, and the price is increased. Furthermore, when a plurality of frequencies of noise generated by resonance are generated, all of them cannot be mechanically handled, and there is a problem that noise cannot be reduced.

  The present invention solves the above-described conventional problems, and can be attached to a motor and a motor even when multiple frequencies of noise generated by resonance occur without adding a mechanism for reducing noise. An object of the present invention is to provide a motor drive control device that suppresses noise generated between a load and a load.

  In order to solve the above problems, a motor drive control device of the present invention includes an inverter circuit that drives a motor, and a control unit that controls the rotation speed of the motor, and the control unit rotates the rotation speed of the motor. Is increased or decreased in a sinusoidal manner around the target rotational speed, and the vibration frequency of the motor itself generated from the natural frequency of the load attached to the motor and the control cycle proportional to the rotational speed of the motor. Without the addition of a mechanism to reduce the noise generated when close to each other, the frequency of noise generated by resonance is generated between the motor and the load attached to the motor even when multiple frequencies are generated. Therefore, it is possible to obtain a motor drive control device that suppresses noises that are generated, thereby reducing the size and cost of the device.

  The motor drive control device of the present invention reduces the noise generated when the natural frequency of a load attached to the motor and the vibration frequency of the motor itself generated from a control cycle proportional to the rotational speed of the motor are close to each other. To obtain a motor drive control device that suppresses noise generated between a motor and a load attached to the motor even when multiple frequencies of noise generated by resonance occur without adding a mechanism of As a result, downsizing and cost reduction of the device can be achieved.

  Embodiments of the present invention will be described below.

(Embodiment 1)
FIG. 1 is a diagram showing a motor drive control apparatus according to an embodiment of the present invention.

  The motor drive control device 1 of this embodiment includes an AC power source 2, a reactor 3 connected to the AC power source 2, a rectifier circuit 4 connected to a small-capacity reactor 3, and an output of the rectifier circuit 4 in parallel. A small-capacity film capacitor 5 connected to the inverter, an inverter circuit 7 for driving the motor 8 connected to the output of the rectifier circuit 4, and the motor current of the motor 8 by controlling the motor current via the inverter circuit 7. A control unit 6 that controls the rotation speed of the motor 8 is provided. Reference numeral 9 denotes a load attached to the motor 8.

  FIG. 2 is a diagram showing a motor drive control device according to another embodiment of the present invention.

  The motor drive control device 1 of this embodiment includes an AC power source 2, a reactor 3 connected to the AC power source 2, a boost converter circuit 10 connected to a small capacity reactor 3, and an output between the boost converter circuits 10. The small-capacity film capacitors 11 and 12 connected to the inverter, the inverter circuit 7 that drives the motor 8 connected to the output of the boost converter circuit 10, and the motor current of the motor 8 is controlled via the inverter circuit 7. Thus, a control unit 6 for controlling the rotation speed of the motor 8 is provided. Reference numeral 9 denotes a load attached to the motor 8.

  FIG. 3 is a diagram showing a rotational speed command according to the embodiment of the present invention.

  Based on the rotational speed range of the motor 8 where the natural frequency f1 and the vibration frequency f2 are close to each other, the control unit 6 controls the rotational speed of the motor 8 so as to suppress noise, and the rotational speed around the target rotational speed. The sine wave amplitude value P and the sine wave period P on the side where the rotational speed is increased or decreased more smoothly than the target rotational speed and the sine wave amplitude value N on the side where the rotational speed is decreased below the target rotational speed. And the sine wave period N are varied in accordance with the variation of the load condition of the motor 8 (the sine wave amplitude value and the sine wave period) to disperse the noise frequency. When the natural frequency f1 of the load 9 attached to the motor 8 and the vibration frequency f2 of the motor itself generated from the control cycle proportional to the rotation speed of the motor are close to each other, noise is generated and the noise of the device is increased. Because it was the cause, less noise was generated.

  The fluctuations in the load condition of the motor 8 are the power supply frequency, the power supply voltage, the ambient temperature, and the heating operation, the cooling operation, and the refrigerant pressure when the compressor is a motor load.

  As described above, the motor drive control device according to the present invention is generated when the natural frequency of the load attached to the motor and the vibration frequency of the motor itself generated from the control cycle proportional to the rotation speed of the motor are close to each other. The noise generated between the motor and the load attached to the motor can be reduced even if multiple noise frequencies are generated by resonance without adding a mechanism to reduce the noise. It is possible to obtain a motor drive control device that can be suppressed, and as a result, it is extremely useful for reducing the size and cost of the device.

Electric circuit diagram of motor drive control apparatus according to Embodiment 1 of the present invention Electric circuit diagram of other motor drive control device Diagram showing the rotation speed command

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Motor drive control apparatus 2 AC power supply 3 Reactor 4 Rectifier circuit 5 Capacitor 6 Control part 7 Inverter circuit 8 Motor 9 Load 10 Boost converter circuit 11, 12 Capacitor 13 Motor drive control apparatus

Claims (7)

An inverter circuit that drives a motor, and a control unit that controls the rotational speed of the motor, wherein the control unit increases or decreases the rotational speed of the motor in a sine wave shape with a target rotational speed as a center. Motor drive control device. The control unit rotates around the target rotation speed with a different value between the sine wave amplitude value on the side that increases the rotation speed above the target rotation speed and the sine wave amplitude value on the side that decreases the rotation speed below the target rotation speed. 2. The motor drive control device according to claim 1, wherein the speed is increased or decreased in a sine wave shape. The control unit sets the rotational speed around the target rotational speed with a different value between the sine wave period on the side where the rotational speed is increased from the target rotational speed and the sine wave period on the side where the rotational speed is decreased below the target rotational speed. The motor drive control device according to claim 1, wherein the motor drive control device increases or decreases in a sine wave shape. The sine wave amplitude value on the side where the rotational speed is increased from the target rotational speed and the sine wave amplitude value on the side where the rotational speed is decreased below the target rotational speed are changed based on fluctuations in the load condition of the motor. The motor drive control device according to claim 2. The sine wave cycle on the side where the rotational speed is increased from the target rotational speed and the sine wave amplitude value sine wave cycle on the side where the rotational speed is decreased below the target rotational speed are changed based on fluctuations in motor load conditions. 4. The motor drive control device according to claim 3, wherein 6. The motor load condition varies as a power supply frequency, a power supply voltage, and an ambient temperature, and particularly when a compressor is used as a motor load, heating operation, cooling operation, and refrigerant pressure are used. Motor drive control device. The motor drive control device according to claim 1, wherein the control unit estimates a rotation speed of the motor based on a motor current and detects a rotation speed based on the estimation.

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