Series-parallel loosely coupling power supply with primary-side control

In this paper, a primary-side control for a series-parallel loosely coupling power supply (SPLCPS) is proposed. Based on the maximum output power criterion the optimal values of the compensated capacitors for such systems are first determined. To impose the operation constraint of minimum volt-ampere (VA) rating of the inverter, the analytical solutions for the multiple operating frequencies as well as the corresponding feasible conditions are then derived. Additionally, six operation modes are proposed to enable the implementation of the proposed primary-side control for the secondary output power. Finally, a SPLCPS is employed with some experimental results to verify the feasibility of the proposed theory.