Design Of Phase-shifted Full-bridge Soft-switching High-frequency&voltage Alternating Current Power Supply.

The structure and principle on phase-shifted soft-switching high frequency& voltage alternating current power supply was analyzed in this thesis. And a high frequency& voltage alternating current(AC) power supply with 5kW output power, 20kV output voltage at frequency of 25kHz has been designed.Most of the main structure of high frequency & voltage power supply adopts the hard-switching PWM in the current time, so the power switches have to endure big stresses of current and voltage and the loss of power results in the low efficiency. This thesis has applied phase-shifted soft switch technology and put Insulated Gate Bipolar Transistor (IGBT) as the switch device in order to solve the energy-loss problem.The topology of main circuit power supply has been presented and the invert part of the phase-shifted soft-switching high frequency AC power supply has been deeply analyzed. And the structure, character and turn-shut of IGBT is introduced in details. And the driving circuit and the protected circuit of IGBT are presented, and the power supply adopts EXB841 as the driving circuit of IGBT. According to the principle of the transformer designing, the circles of primary side and second side have also been given out. By simulation analysis, the parameters of output filter are calculated. The power supply adopts ML4818 to make shifted phase and UCC3895 as the main circuit controller, he soft-start method of controller and two control methods of full bridge are also introduced in details. Combined with the requirement of high-frequency and high-voltage inverter power supply, the method of single-stage of phase shift has been adopted.In the end, the thesis uses PSpice to simulate the main circuit of the inverter. By giving out the Zero-Voltage-Switching waveforms of phase-shifted soft-switching inverter, we could realize that the high-frequency high-voltage inverter power supply with soft-switching has the more advantages. And the loss power waveform of the main switch is also given out. The thesis also analyzes the source of the energy loss. The thesis provides the good suggestions in designing soft-switching high-frequency high-voltage alternating current power supply. The experiment results have been given out to prove the power supply is available.