Suppression method of pure electric vehicle rotation speed fluctuation

Abstract

The present invention discloses a suppression method of a pure electric vehicle rotation speed fluctuation. A motor driving system gives a motor expected rotation speed omega<+> and collects the actual rotation speed omega of the motor, and the deviation between the two speeds is inputted into a PI controller, the PI controller outputs an expected torque T<+>[e]. The expected torque T<+>[e] is subjected to gradient amplitude limitation algorithm processing through a gradient amplitude limitation module, an amplitude limitation torque T[e] is obtained and is used as the input of a current calculation module, and expected exciting current i<+>[sd]and torque current i<+>[sq]are obtained. Through a closed loop PI control module, steady-state values are achieved and control voltage u<*>[sd] and u<*>[sq] are outputted, a pulse width modulation module controls a power module to drive the motor to generate stable torque so as to balance the load torque, and the suppression of the rotation speed fluctuation is realized. Based on vector control, the torque given value outputted by the torque deviation PI controller is subjected to gradient amplitude limitation, the torque which is subjected to amplitude limitation is used as an actual torque output value, and thus the suppression of the rotation speed fluctuation is realized.

Description

technical field [0001] The invention relates to a method for suppressing rotation speed fluctuations of pure electric vehicles. Background technique [0002] The performance of a pure electric vehicle depends on the performance of the electric drive system. In addition to ensuring the power performance of a pure electric vehicle, the electric drive system also needs to take into account the smoothness and suppleness of the control during the operation of the vehicle. However, due to the random and changeable road conditions during the driving process, the load torque will change instantaneously. If the speed regulation algorithm of the vehicle control strategy is not coordinated properly, it will easily cause fluctuations in state quantities such as current, torque, and speed. This kind of fluctuation will not only affect the driving stability of the electric vehicle, but also cause the error of the magnetic field orientation in the vector control, aggravate the oscillation ...

AI Technical Summary

Problems solved by technology

When the speed reaches a steady state, due to the influence of factors such as load torque fluctuations, the actual speed at desired speed Fluctuates up and down, and because the desired torque It is the output value of the speed deviation PI controller 1, so it will change back and forth with the fluctuation of the speed, which will further cause the fluctuation of the speed and induce a large oscillation of the speed

In addition, the selection of PI parameters in this method is complicated, and the workload of parameter adjustment is large, which makes it difficult to suppress the speed fluctuation.

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