Chebyshev polynomials based compensator design via higher order sinusoidal input describing functions in traction motor drive to improve performance of electric vehicle

Abstract

In electric vehicles (EVs), the efficient selection of the basic elements and the control of the electric motor and the overall system is vital to extend the performance of the vehicle. A feedback control loop with proportional-integral (PI) controllers is usually used in the control of electric motors. Within the scope of this study, the system is handled with frequency-based methods and it is aimed to reduce the performance degrading effect on the system output. In this study, Higher Order Sinusoidal Input Describing Functions (HOSIDFs) are used in order to improve the performance of EVs. Here, the EV is modeled as a Lur'e-type system and a compensator is designed within the PI speed control loop of the electric motor by using Chebyshev polynomials. The optimal coefficients of the Chebyshev polynomials-based compensator minimize the cost function which is related to the harmonics of the system output. This work introduces a novel approach for controlling the traction motor of EVs using a frequency-based method through HOSIDFs. The objective is to enhance the performance of the drive system. Throughout this study, it is also aimed to improve the consumption of the battery and passenger comfort. The results and success of the proposed method are illustrated in time-domain and harmonic plots.