Research On High Frequency Inverter Power Controlled By ZCS-DPLL

In order to improve the efficiency of the power and reduce the losses of switching components, the operating frequency of the inverter power is controlled, so as to track the load resonant frequency simultaneously to keep the inverter always operating in Zero-Current-Switching (ZCS) mode. As a result of the shortcoming of traditional simulate Phase-Locked Loop ,in this paper ,the Digital Phase-Locked Loop (DPLL) technology based on DSP is applied to control the operating frequency of an HF-Inverter power simultaneously to track the load resonant frequency.Firstly, the basic principals of the resonant tank and the two main topologies are analyzed in detail. This paper selects the series-resonant inverter because it is more suited to high frequency power supply. At the same time, the mode of power control is chose by analyzing all kinds of control methods.Secondly, the mode of frequency control is chose by analyzing the principle and characteristic of PLL. Its mathematic models are set up and simulated. The stability analysis and dynamic design of the second-order DPLL is completed in the Z-plane. From the above stability analysis, the condition stabilizing DPLL is observed. In the base of theory analysis of DPLL, combined with DSP technology, the HF-Inverter power system is designed which includes hardware circuit and software program.At last, the models of the inverter using the DPLL are constructed in MATLAB/SIMULINK environment. The results of simulation show that the dynamic analysis and design of the second-order DPLL controller is reasonable and feasible, also it indicates that the HF-Inverter power using the DPLL technique has good characteristic of frequency tracking to keep the inverter always operating in ZCS mode.The HF-Inverter using the DPLL technique has simple main circuit, good characteristic of frequency tracking, high output frequency, high output stabilization, high input power factor. Also the DPLL technique has a brilliant future in application in the HF-Inverter power.