Fault monitoring and fault-tolerant control method for electric vehicle driving system

Abstract

The invention discloses a fault monitoring and fault-tolerant control method for an electric vehicle driving system. The method overcomes the problem that incremental signals A and B of a magnetoelectric hybrid type encoder fail to cause that the driving system loses accurate position information. The method comprises the following steps: firstly, judging the initial rotor position of a permanent magnet synchronous motor by a motor control unit; secondly, controlling motor start-up in a six-pulse control mode according to the initial rotor position by the motor control unit; thirdly, judging whether the height of any path of level in the levels of absolute signals HA, HB and HC of the magnetoelectric hybrid type encoder changes by the motor control unit, entering a fourth step if the change occurs, if not, returning to the second step; fourthly, obtaining accurate rotor absolute position information according to the absolute signal level change edge of the magnetoelectric hybrid type encoder; fifthly, collecting the current state Q(n) of the incremental signals of the magnetoelectric hybrid type encoder by the motor control unit; ......; and ninthly, carrying out space vector calculation by utilizing the rotor position information calculated in the seventh step or the eighth step by the motor control unit so as to complete a one-time timer interruption task.

Description

technical field [0001] The invention relates to a control method of an electric vehicle drive system, more precisely, the invention relates to a fault monitoring and fault-tolerant control method of a permanent magnet synchronous motor drive system for an electric vehicle. Background technique [0002] The permanent magnet synchronous motor drive system is the mainstream drive system of electric vehicle motors, which has the characteristics of high power density, small size, and wide speed range. The drive system mainly uses the space vector control method to control the motor movement. The vector control method needs to detect the absolute position of the permanent magnet synchronous motor rotor in real time. Therefore, a position sensor must be installed on the motor body to measure the rotor position in real time. [0003] There are two types of rotor position sensors for permanent magnet synchronous motor drive systems: hybrid photoelectric encoders and resolvers. The co...

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Problems solved by technology

[0005] However, the working environment of the automobile is harsh, and the magnetoelectric hybrid encoder has a high probability of short circuit and open circuit electrical failure. When the sensor failure causes the incremental signals A and B of the magnetoelectric hybrid encoder to fail, the control system cannot calculate the rotor arbitrary Accurate position information at all times will not be able to complete the expected control, and the motor rotor may be locked in a fixed position during operation, and the motor will not be able to run, which may easily lead to traffic accidents

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