Resonant inverter application with PLL control technic

In this study, D-Class resonant inverter systems have been controlled with PLL technique. Zero crossings of current and voltage on the resonant leg are sensed by using a data acquisition board and then are transferred to the dsPIC30F2020 microprocessor. The developed PLL control algorithm, measures phase difference between the voltage and current signals and controls the system switching frequency by using PI controller to obtain zero phase difference, and achieves the resonant frequency. Zero current switching is obtained at the resonant frequency and switching stress, power losses and EMI values are minimized. Thus, system size and cost have been reduced via obtaining high frequency switching that is limited because of the switching losses, high power density design and high efficiency are obtained. In addition, system size and cost is reduced. The current of the resonant branch is also limited to prevent the damages on the circuit components by using software.