Vision-Based Power And Efficiency Control For The Dynamic Wireless Power Transfer System

Dynamic wireless power transfer brings a refreshing way for charging electric vehicles(EVs)in motion,which can help reduce the amount and bulk of onboard batteries and prolong the vehicle mileage.However,the misalignment between the transmitter coil and receiver coil varies randomly as the vehicle moves,causing changes in mutual inductance,which reduces the stability of the output power and the system efficiency.Therefore,a guiding approach is imperative to maintain the coil alignment within an acceptable range.Therefore,a fast and effective detection method is urgently needed to estimate the mutual inductance M,and the circuit is adjusted according to the estimated mutual inductance to improve the stability of the output power.In this paper,a vision-based misalignment detection method is proposed to improve the stability of the system output power and the efficiency.Firstly,the relationships among the system efficiency,output power and mutual inductance were derived in theory.Then,the relationship between the mutual inductance and the misalignment was modeled and simulated using ANSYS Maxwell software.Thirdly,the vision system is calibrated and image detection of the ground guideline was used to locate the transmitter coil,and thus obtain the accurate misalignments online.Based on the acquired misalignments,the output power can be rapidly and precisely regulated to the desired value.Finally,the experimental results show that the proposed method can accurately acquire the coil misalignments and then rapidly regulate the system output power in comparison with the conventional discrete PID control algorithm.In addition,in order to solve the parameter optimization problem of dynamic wireless charging system,this paper proposes a parameter optimization method based on the weighted average efficiency in the spatial domain to optimize the parameters of each component of the topology compensation structure.A prototype is implemented based on the optimized parameters.The proposed method is verified by Simulink and experiment,the results indicate that the proposed method based on the weighted average efficiency in the spatial domain can improve the system output power and efficiency compared with the TWAE(Time-Weighted Average Efficiency)method when applied to DWPT systems.The experimental results show that the optimization method proposed in this paper can obtain higher transmission efficiency and output power than the TWAE method under different lateral offset distances,and the maximum operating efficiency of the experimental system reaches 85.2%.