Transmitter-Side Control of Both the CC and CV Modes for the Wireless EV Charging System With the Weak Communication

Abstract

Due to the convenience, safety, and aesthetics, the wireless charging is promising for the electric vehicles. For the charging system, the real-time wireless communication between the transmitter and receiver sides is conventionally used for the closed-loop control of the transmitter-side inverter. However, since the real-time wireless communication depends on the data transmission with the high speed and the low latency, it is sensitive to the interference. In order to improve the reliability and reduce the cost, the concept of the weak communication is introduced, and a transmitter-side control scheme is proposed to realize both the constant current (CC) and constant voltage (CV) charging modes as well as the smooth transition between the two modes. In the proposed control scheme, the mutual inductance is estimated without using the structural parameters in the receiver side. The online recursive least square filter is adopted to reduce the influence of the sensor noise for the estimation. Based on the estimated mutual inductance and the information obtained from the weak communication: 1) for the CC mode, the control command for the target charging current of the battery management system is calculated out directly and 2) for the CV mode, the reference transmitter current for the target charging voltage is calculated and a closed-loop control is used to make the transmitter current trace the reference value. The proposed control scheme is robust and can be easily implemented. Experimental results have confirmed the feasibility and the validity of the proposed scheme.