Electric vehicle permanent magnet synchronous motor back electromotive force suppression method and system

Abstract

The invention discloses an electric vehicle permanent magnet synchronous motor back electromotive force suppression method and system, and relates to the technical field of electric vehicles, the method comprises the following steps: if an electric vehicle is in a motor high-speed power failure or fault high-speed trailer state and the current rotating speed of the motor is greater than a preset rotating speed, adjusting the exciting current and the torque current according to the voltage of the bus capacitor, and controlling the on-off of a switching device in the three-phase bridge circuit,so that the voltage of the bus capacitor is within a preset voltage range until the current rotating speed of the motor is not greater than the preset rotating speed. According to the back electromotive force suppression method and system for the permanent magnet synchronous motor of the electric vehicle, the bus capacitor and a switching device in a three-phase bridge circuit are protected against damage, meanwhile, the whole vehicle has enough time, the vehicle speed is reduced to zero through a braking system, the motor efficiency cannot be reduced, the motor cannot be overheated, and the maintenance cost cannot be increased.

Description

technical field [0001] The invention relates to the technical field of electric vehicles, in particular to a method and system for suppressing back electromotive force of a permanent magnet synchronous motor of an electric vehicle. Background technique [0002] With the development of society, electric vehicles, as new energy vehicles, conform to the development trend of energy saving and environmental protection. Permanent magnet synchronous motors have become the primary choice for electric vehicle drive motors due to their high power / torque density and high efficiency. However, permanent magnet synchronous motors are excited by permanent magnets. When the vehicle is driving at high speed and the power is abnormally cut off or the high-speed faulty trailer needs to be maintained, the back electromotive force generated on the motor windings will be generated. Since the back electromotive force is proportional to the motor speed, when the back electromotive force is greater...

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Problems solved by technology

[0008] The embodiment of the present invention provides a method and system for suppressing the back EMF of a permanent magnet synchronous motor of an electric vehicle to solve the problem of reducing the efficiency of the motor, causing the motor to overheat or increasing the maintenance cost in the existing method and system for suppressing the back EMF of the permanent magnet synchronous motor of the electric vehicle technical problem

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