A direct torque control system and method for a permanent magnet synchronous motor for an electric vehicle

Abstract

The invention discloses a system and method for controlling direct torque of a permanent magnet synchronous motor for an electric automobile. According to the method, a three-phase current, a voltage and an inverter direct-current bus voltage output by an inverter are firstly detected, electromagnetic torque, a stator flux linkage and the section area theta where the stator flux linkage is located under a current state are obtained through a torque, magnetic linkage and theta calculating unit, small-wave multi-resolution MRPID control and integral structure composite control are adopted in a speed ring, the calculated magnetic linkage and the calculated torque are compared with the given magnetic linkage and the given torque signal output by a composite control adjustor respectively, the current error state of the magnetic linkage and the torque is output and decides a selected voltage vector together with the section area where the magnetic linkage is located, and therefore the on-off state of the inverter is further decided, and the operation of the permanent magnet synchronous motor is controlled. The system and method for controlling the direct torque of the permanent magnet synchronous motor for the electric automobile has the advantages of being simple in structure, novel in concept, fast in response and the like, the small-wave multi-resolution MRPID control and the integral structure composite control are adopted in the speed ring, and the control has the advantages of being wide in control range, high in precision, fast in response and the like.

Description

technical field [0001] The invention belongs to the technical field of AC motor transmission, and relates to a direct torque control system and method for permanent magnet synchronous motors used in electric vehicles based on wavelet multi-resolution MRPID control and integral structure composite control. Background technique [0002] The energy and environmental issues and the financial crisis faced by the automobile industry have made the research on electric vehicles attract extensive attention from all over the world. In addition to showing superiority and strong competitiveness in energy environmental protection and energy saving, electric vehicles also show huge advantages in vehicle performance. The torque response of electric vehicles is fast and the acceleration is fast, which is 2 orders of magnitude higher than that of fuel vehicles. The motor can be configured in a decentralized manner, and the wheel speed can be directly controlled by wire transmission electroni...

AI Technical Summary

Problems solved by technology

However, as an emerging control method, direct torque control has the problems of severe flux linkage and torque ripple, and poor low-speed performance.

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