Research on multi-load wireless power transfer system considering coupling between receiving coils

In the multi-load magnetic coupling resonance wireless power transmission（MCR-WPT）system, the multiple receiving coils are coupled with each other in close proximity, which affects the system transmission efficiency and the load receiving power. To solve this problem, an equivalent circuit model with controlled sources is established for the multi-load system, the influence of the coupling between the receiving coils on the transmission characteristics is explored. Then a decoupling method based on the series compensation capacitor in the receiving loop is proposed. For the decoupled system, a method is proposed to achieve the capacitor compensation decoupling and load resistance matching by controlling the phase and amplitude of input voltage for the PWM rectifier. Thus, the system can achieve decoupling while operating under two conditions: one that maximizes transmission efficiency and another that enhances the receiving power at a designated load after decoupling. The experimental results show that the coupling coefficient k12 between the receiving coils is in the range of 0-0.1, the system achieves decoupling and the transmission efficiency is higher than 87%, and the maximum efficiency is 89.7%. Input voltage VDC=30V, MP1=MP2=6μH, RL1=30Ω, RL2=25Ω, and k12=0.1, the maximum received power of load 1 is 21W, which verifies the correctness of the theoretical derivation.