Series-parallel loosely coupled battery charger with primary-side control

In this paper, a primary-side control for a series-parallel loosely coupled inductive power transfer systems (SP-LCIPTS) is proposed. Based on the maximum output power criterion, the optimal values of the compensated capacitors for such systems are determined first. Six operation modes to enable the implementation of the proposed primary-side control for the secondary output power are then derived. Finally, a battery package composed of two 24V 4.5 Ah lead-acid batteries is employed with some simulated and experimental results to verify the feasibility of the proposed batter charger.