Electric vehicle, suppression method and suppression system of rotation speed fluctuation of permanent magnet synchronous motor

Abstract

The embodiment of the invention provides a suppression method and suppression system of the rotation speed fluctuation of a permanent magnet synchronous motor. The method includes the following steps that: the rotation speed of the permanent magnet synchronous motor is obtained in each preset period, and the variation quantity of the rotation speed of the permanent magnet synchronous motor is calculated through using the rotation speed of the permanent magnet synchronous motor in the current period and the rotation speed of the permanent magnet synchronous motor in the last period; a first preset database is queried according to the rotation speed in the current period, so that a compensation torque coefficient can be determined, and a second preset database is queried according to the rotation speed in the current period, so that a compensation torque limit value can be determined; theoretical compensating torque is calculated through utilizing the compensation torque coefficient and the variation quantity of the rotation speed of the permanent magnet synchronous motor, and the theoretical compensating torque is compared with the compensation torque limit value, so that actual torque compensation torque can be determined; and the actual compensation torque is transmitted to the permanent magnet synchronous motor. With the method adopted, jigger generated when the permanent magnet synchronous motor is applied to an electric vehicle can be reduced, and the driving comfort of the electric vehicle can be improved.

Description

technical field [0001] The invention relates to the field of electric vehicles, in particular to a method and a system for suppressing rotation speed fluctuations of electric vehicles and permanent magnet synchronous motors thereof. Background technique [0002] With the increasing shortage of fossil energy and the increasing environmental pollution, the advantages of electric vehicles over traditional vehicles have become more and more obvious, and their use in the market is also becoming more and more extensive. However, the permanent magnet synchronous motor and the reducer of the electric vehicle are connected by splines, and the clutch and flywheel in the traditional car are removed in the middle, so that there are greater requirements for the speed control of the permanent magnet synchronous motor. In the power transmission system of an electric vehicle, the permanent magnet synchronous motor and the reducer are connected by internal splines and external splines, becau...

AI Technical Summary

Problems solved by technology

In the power transmission system of an electric vehicle, the permanent magnet synchronous motor and the reducer are connected by internal splines and external splines, because there is a gap between the internal splines and the external splines, and There is also a gap between the reduction gears inside the reducer. When the depth of the accelerator pedal changes or the torque of the permanent magnet synchronous motor changes positively or negatively, the internal splines and the external splines of the power transmission system The contact surface of the key and the contact surface between the reduction gears inside the reducer will jump, causing the speed of the permanent magnet synchronous motor to fluctuate, causing the electric vehicle to vibrate, which seriously affects the driving comfort of the electric vehicle

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