Feedforward Proportional Integral Resonant controller-based current ripple reduction in CL 3 C resonant DC-DC converter

Abstract The LLC(Inductor-Inductor-Capacitor) DC-DC resonant converter is presently employed for EV charging with high power handling capacity and compact size. The technological advancement urges the need for bidirectional power flow for V2X operation to boost the charging to the next level. The CL3C converter is the ideal choice for that with high power density with Zero voltage and current switching. Apart from that, the high-frequency operation increases the higher order current ripple, which increases the battery temperature and reduces the battery life. As per standard IEC 60086, the low-frequency current ripple should be less than 5% to recuperate the battery life. The Feedforward Proportional Integral Resonant (FF-PIR) controller gives better ripple reduction and improves the converter performance along with better battery life. The results show that the controller improves the efficiency of the converter by reducing the ripple content in the current and enhancing the output voltage for the same input voltage. The FF-PIR controller is best suited for resonant converters to enhance battery charging by increasing the efficacy of the converter. The optimal design of the converter and the tuning of the FF-PIR controller is done, and the performance of the controller with the plant is analyzed. The controller robustness is also addressed for the variation in the frequency.