Stability analysis of multi-load inductively coupled power transfer system

Multi-load inductively coupled power transfer system may emerge multiple resonance point, due to the resonance compensation topologies, which leads to the instability of frequency control. Therefore, this paper focuses on the stability analysis of multi-load system. In this paper, the mutual coupling model is used to obtain the equivalent reflected impedance of the secondary system; the primary resonant capacitance at secondary resonance frequency is given for maximum power transfer capability; finally, the stability conditions are stated according to conditions of single zero primary impedance angle. When quadratic sum of all the coupling coefficients and the quality factor of the secondary system conform to the stability conditions, the system works in the stable region. The simulation analysis verifies the correctness of the theory.