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Drive system for synchronous motor

A synchronous motor and drive system technology, which is applied in the estimation/correction of motor parameters, motor generator control, AC motor control, etc., to achieve the effect of increasing the number of switches

Active Publication Date: 2014-01-22
HITACHI LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The rotor of the permanent magnet motor is required to have a salient polarity, and the position detection becomes possible by the influence of the current harmonic caused by the salient pole structure

Method used

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  • Drive system for synchronous motor
  • Drive system for synchronous motor
  • Drive system for synchronous motor

Examples

Experimental program
Comparison scheme
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no. 1 approach ）

[0066] figure 1 It is a block diagram showing the configuration of the motor drive system according to the first embodiment of the present invention.

[0067] The purpose of this motor drive system is to drive a permanent magnet motor (three-phase synchronous motor) 4 . Roughly, the motor drive system includes an Iq* generator 1, a controller 2, an inverter 3, and a permanent magnet motor 4 as a driving object, wherein the inverter 3 includes an inverter main circuit 32 and a single current (one-shunt) detector 35 .

[0068] The Iq* generator 1 is a circuit that generates a current command Iq* corresponding to the torque of the motor. The Iq* generator 1 is a superordinate controller to the controller 2 . Usually, the configuration is such that the necessary current command Iq* is generated while observing the actual speed ω1 in order to make the number of revolutions of the permanent magnet motor 4 a predetermined speed. The current command Iq* which is the output of the...

no. 2 approach ）

[0123] Next, a second embodiment of the present invention will be described.

[0124] In the first embodiment, in order to detect Vn0, by introducing the pulse shifter 17 and shifting the PWM pulse wave, the output period of the voltage vector other than the zero vector can be extended, and two types of voltage vectors not included in the original PWM waveform can be newly output. vector, thereby improving the position estimation accuracy.

[0125] In the example of the first embodiment, V(1, 1, 0), V(0, 1, 0). here, from figure 2(a) It can be known that V(0, 0, 1) and V(1, 1, 0) and V(1, 0, 1) and V(0, 1, 0) are vectors in opposite directions respectively. Not only adding the vector in the opposite direction like this, but also adding the voltage vector in the direction not included in the PWM before the pulse shift, such as V (1, 0, 0), produces the effect of exploring the rotor position and can further improve the rotor position. the precision of the information. For ...

no. 3 approach ）

[0129] Then for the third embodiment of the present invention, use Figure 7 Be explained.

[0130] In the first and second embodiments, it is shown that the voltage vectors applied to the motor can be increased from two to three or four by introducing the pulse shifter 17 . In these embodiments, all three phases are switched at the same frequency as the triangular wave carrier. In contrast, in the third embodiment, an example in which the switching frequencies of three phases are different (two-phase switching) will be described.

[0131] Figure 7 (a) shows a two-phase switching method using a triangular wave carrier. can be known with Figure 4 Differently, the three-phase voltage commands Vu*, Vv*, Vw* are close to the upper peak of the triangular wave carrier. In this example, Vw* of the maximum value among the three-phase voltage commands coincides with the peak value of the upper wave of the triangular wave carrier. In this way, by setting the same offset value fo...

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Abstract

Provided is a position-sensorless drive method, wherein control of the rotational speed and torque of a permanent-magnet motor is executed by driving the motor with an ideal sinusoidal-wave current generated by a minimum necessary number of switching, using an inverter, and wherein driving from an extremely low speed range in the vicinity of zero is possible. A neutral point electric potential of a permanent-magnet motor (4) is detected by synchronizing with the PWM waveform of an inverter. The position of a rotor of the permanent-magnet motor (4) is surmised from changes in the neutral point electric potential. The rotor position of a three-phase synchronous motor is surmised by making, upon detecting the neutral point electric potential, three or four types of switching states wherein the output voltage of the inverter is not a zero vector, by shifting the timings of each of the phases of the PWM waveform, and sampling the neutral point electric potential in at least two types of switching states among those switching states.

Description

technical field [0001] The present invention relates to motor drive devices such as devices for controlling the rotational speed of fans, pumps, compressors, rotating electrical machines, etc., or positioning devices in conveyors or working machines, and synchronous motors used in torque control applications such as electric power assist Drive System. Background technique [0002] Small, high-efficiency permanent magnet motors (three-phase synchronous motors) are widely used in various fields such as industry, home appliances, and automobiles. [0003] However, in order to drive the permanent magnet motor, position information of the rotor of the motor is required, and a position sensor provided therefor is required. In recent years, sensorless control in which the rotation speed and torque of the permanent magnet motor are controlled without the position sensor has been widely spread. [0004] The practical use of sensorless control has reduced the cost required for the p...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02P21/00H02P27/04H02P6/08H02P6/06H02P6/17H02P6/18H02P6/182H02P6/28H02P21/14H02P21/18H02P21/22H02P21/24H02P21/28H02P23/14H02P23/16H02P23/18H02P27/08
CPCH02P27/08H02P21/04H02P21/24H02P6/187
Inventor 岩路善尚青柳滋久高畑良一户张和明
Owner HITACHI LTD
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