FREQUENCY ADAPTIVE DISCRETE REPETITIVE CONTROLLER DESIGN FOR ELECTRIC VEHICLE CHARGER

Abstract

Electric vehicles (EVs) are very efficient, cheap, and cause less pollution to environment that internal- combustion (IC) engine base vehicles. As EVs are gaining lot of popularity globally so it becomes very important to standardize its infrastructure. This paper summarizes the various charging standards followed by different country regions globally and focuses the standards adopted by India. As of now, every standard identified with charging infrastructure depend on the European ambient conditions. As India being a tropical country, subsequently settling the EV charging standards, vehicle adoption pattern and India's encompassing temperature will become basic contemplations. Therefore, India has followed and modified various other standards to comply with Indian conditions This research work introduces the designing of bidirectional two-stage, on-board electric vehicle (EV) charger’s controller. As with the growing trend of EVs, their widespread use may compromise grid quality, leading to the demand for a stable, simple, and better control system. However, some controllers provide sluggish responses and fail to compensate for harmonics. Therefore, to mitigate the grid current harmonics, repetitive controller (RC) has been analyzed. Within a specified integer period, the RC may accomplish zero steady-state error tracking of any periodic signal. However, the performance of conventional RC degrades when grid frequency varies within the permissible range. Therefore, a Lagrange interpolating polynomial-based fractional-order RC has been implemented with a fixed sampling rate to enhance its performance during frequency fluctuations. The PLL estimated frequency has been fed back to update the controller's resonant frequency, and the fractional delay is approximated using a Lagrange interpolating polynomial. The proposed controller has been designed within a MATLAB environment. Its performance has also been tested in a real-time experimental setup using OPAL-RT (4510).