Three-phase permanent magnet motor driving circuit and control method

Abstract

The invention relates to the technical field of motor driving, in particular to a three-phase permanent magnet motor driving circuit and a control method. The three-phase permanent magnet motor driving circuit comprises a three-phase half-bridge inverter circuit, the three-phase half-bridge inverter circuit is formed by connecting three single-phase half-bridge inverter circuits in parallel, and the three-phase half-bridge inverter circuit is also connected with a capacitor in parallel; the three-phase half-bridge inverter circuit and the capacitor are both powered by a direct-current power supply; a three-phase line is led out from the external output end of the three-phase half-bridge inverter circuit, a high-voltage semiconductor device is connected in series in each phase line in the three-phase line, and the tail end of the three-phase line is electrically connected with the three-phase permanent magnet motor and drives the three-phase permanent magnet motor. According to the invention, the problem of contradiction between safety and control performance when the motor is driven by a conventional three-phase half-bridge is solved; in addition, a semiconductor device which is matched with the direct-current side and has a low voltage level can be adopted, the cost and the size can be reduced, and meanwhile high switching frequency can be adopted to meet the requirement for control performance.

Description

technical field [0001] The invention relates to the technical field of motor drive, in particular to a three-phase permanent magnet motor drive circuit and a control method. Background technique [0002] The application of three-phase permanent magnet motor is mature, and it is one of the current mainstream motor types. The three-phase permanent magnet motor drive circuit mostly adopts the three-phase half-bridge topology, and the related modulation technologies include SPWM and SVPWM, etc., which have been developed to a very mature level. In order to obtain higher power density, the maximum speed back electromotive force of permanent magnet motor design is often higher than the previous DC bus voltage, so it is necessary to use the field-weakening speed-up technology in the high-speed section, but at the same time considering the fault conditions such as control failure, the permanent magnet The highest speed back EMF of the motor should be lower than the highest withstan...

AI Technical Summary

Problems solved by technology

[0004] However, in the traditional three-phase half-bridge structure, when driving a motor with a very high back EMF, if a semiconductor switch with a lower voltage level matching the DC bus is selected, there will be safety risks. If a higher voltage matching the motor back EMF is selected High-level semiconductor switches have the problems of high cost and high switching loss resulting in extremely low efficiency

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