DC Voltage Drop Compensation in Automotive Drives by Finite Set Model Predictive Control

Abstract

this paper aims to provide a modified predictive direct torque control using a field-weakening strategy which can be used for traction electric vehicle (EV). One of the problems in the control of EV motors is the drop of DC link voltage which is very important for EV speed and load bearing. Most of the methods that proposed a solution for this problem are based on a field weakening strategy. The demanded voltage of the pulse width modulation (PWM) is the base of the compensation. On the other hand, one of the most effective methods for induction motor control (IM) is finite set model predictive control (FS- MPC) because of its less computation burden, accurate control, fast dynamic response, etc. Since there is no modulator in this method, the application of the field-weakening technique for DC voltage compensation is a challenge and there is a need for a method to use the flux and torque references and obtain the voltage reference. So the simplified predictive direct voltage control is applied in this research which can solve this problem. Also, another advantage of the predictive direct voltage control is using a simplified cost function without a weighting factor. A modified flux reference is proposed for the simplified FS-MPC method to compensate for the drop of the DC link voltage. The proposed method is an effective method for traction EV motor control to overcome the DC link voltage disturbances. The proposed method is evaluated by simulations.