Nonlinear-control strategy for the half-bridge series-resonant inverter

This paper concerns the analysis and design of the half-bridge series-resonant inverter with nonlinear-control strategy. A zerocurrent-switching (ZCS) half-bridge series-resonant inverter with nonlinear control is built. The presented circuit topology is simply configured by two power switches and one output filter. Only one conduction loss of the power switch is present in the power flow path during the inversion period. A turn-on ZCS for the power switch is achieved by an auxiliary resonant cell built before the output choke. The nonlinear-control strategy is designed against the input DC perturbation and achieves good dynamic regulation for the sinusoidal pulsewidth-modulation control. A state-space averaging approach is employed to analyze the system. A design example of a 500-W inverter is examined to assess the inverter performance and it provides high power efficiency above 91% under the rated power.