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Drive system of synchronous motor

A synchronous motor and drive system technology, applied in motor control, AC motor control, electronic commutation motor control, etc., can solve the problem of inability to obtain position information, and achieve the effects of reducing noise, reducing vibration, and shortening starting time.

Inactive Publication Date: 2010-03-24
RENESAS ELECTRONICS CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, since the induced voltage itself of the third harmonic is the speed-induced electromotive force accompanying the rotation of the permanent magnet motor, position information cannot be obtained in the low-speed range

Method used

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  • Drive system of synchronous motor
  • Drive system of synchronous motor
  • Drive system of synchronous motor

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Experimental program
Comparison scheme
Effect test

no. 1 approach

[0061] figure 1 It is a block diagram of the structure of the motor drive system of 1st Embodiment of this invention.

[0062] The purpose of this motor drive system is to drive a permanent magnet motor (three-phase synchronous motor) 4 . If roughly distinguished, the motor drive system includes: Iq ＊ A generator 1, a controller 2, an inverter 3 including an inverter main circuit 32 and a single-branch current detector 35, and a permanent magnet motor 4 as a driving object.

[0063] Iq ＊ Generator 1 generates a current command Iq equivalent to the torque of the motor ＊ circuit. The Iq ＊ The generator 1 is a higher-level controller than the controller 2 . Usually, the configuration is such that the required current command Iq is generated while observing the actual speed ω. ＊ , so that the rotational speed of the permanent magnet motor 4 becomes a predetermined speed. Iq ＊ The output of the generator is the current command Iq ＊ is output to the subtractor 6-2 in the c...

no. 2 approach

[0119] Next, a second embodiment of the present invention will be described.

[0120]In the first embodiment, the reference level Vh is set, compared with the neutral point potential Vn0h, and the phase is updated when the comparison result exceeds a predetermined value. The reference level Vh at this time is a fixed value.

[0121] If the reference level Vh is a fixed value, the scale of the phase information expressed in electrical angle is 60 degrees, which is too low resolution for an ideal sine wave current to drive a permanent magnet motor. The second embodiment aims to solve this problem.

[0122] Figure 9 It is a block diagram of the configuration of the position estimator 15B of the second embodiment. In this embodiment, a position estimator 15B is used instead of the position estimator 15 of the first embodiment.

[0123] The position estimator 15B is composed of a switch 154 , a first memory 155 , a second memory 156 , a position estimator 157 , and a neutral p...

no. 3 approach

[0130] Next, a third embodiment of the present invention will be described.

[0131] In the first and second embodiments, a normally operating PWM signal is used, and the neutral point potential is detected in synchronization with the PWM signal to obtain position information. As described above, the fluctuation of the neutral point potential depends on the magnetic circuit characteristics inside the permanent magnet motor 4 . Therefore, the characteristics of the permanent magnet motor 4 are greatly different depending on the specifications such as capacity and rotational speed. It is also considered that the detection sensitivity of the position information is insufficient depending on the structure of the motor.

[0132] This embodiment solves the above-mentioned problems. In this embodiment, the detection pulse of the neutral point potential is intentionally inserted to generate an isoelectric period insertion sampling period, and the neutral point potential is observed ...

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Abstract

A position sensorless drive method capable of driving a permanent magnet motor by an ideal sine-wave current and enabling the driving from an extremely low-speed range in the vicinity of zero-speed is provided. A neutral-point potential of the permanent magnet motor is detected in synchronization with a PWM waveform of an inverter. The position of a rotor of the permanent magnet motor is estimated from the variation of the neutral-point potential. Since the neutral-point potential is varied in accordance with the magnetic circuit characteristics of an individual permanent magnet motor, the position can be detected regardless of the presence of saliency of the permanent magnet motor.

Description

technical field [0001] The present invention relates to techniques for rotational speed control of motor drive devices such as hard disk drives (HDDs), optical disk drives, spindle motors, fans, pumps, compressors, and the like. Background technique [0002] Small and efficient permanent magnet motors (three-phase synchronous motors) are widely used in motor drive devices such as spindle motors, fans, and pumps of HDD devices. [0003] However, in order to drive a permanent magnet motor, position information of a rotor of the motor is required, and thus a position sensor for the position information is required. In recent years, sensorless control that controls the rotational speed and torque of a permanent magnet motor without the position sensor has been widely used. [0004] The practical application of the sensorless control can reduce the cost related to the position sensor (the cost of the sensor itself, the wiring of the sensor, etc.), and realize the miniaturization...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02P6/18H02P27/06H02P6/06H02P6/08H02P6/182H02P6/21H02P6/28
CPCH02P6/187H02P2207/05H02P21/04H02P21/0053H02P21/32
Inventor 岩路善尚鸿上康彦黒泽稔
Owner RENESAS ELECTRONICS CORP
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