The Study And Design Of Phase-shift Full-bridge High-power High-frequency Switching Power Supply

Currently, the charging power supply of high-power laser front-end storagecapacitor that is primarily adopts three-phase uncontrolled rectifier. The rectifiercircuit can only drop voltage, therefore, in order to satisfy the requirement of the laserpower, it generally uses the power frequency transformer to boost, it leads to thepower supply that is low efficiency and large bulk. In order to improve the efficiencyof power supply and reduce equipment bulk, combining with the requirements ofenterprise cooperation projects, it studies and implements the ZVS phase-shift fullbridge switching power supply used for charging to storage capacitor of the laserdevice front-end, it is power rating of10kW, switching frequency of30kHz, outputdc voltage of0v to800v. The main research contents are as follows:1. According to power requirements of studying and producing switching power,the main circuit uses DC/DC full-bridge topology that is applied to high-powerpower conversion, and it analyzes the composition structure and working principle ofphase-shift control ZVS-PWM DC/DC full-bridge converter.2. According to the principle and control objectives of the phase-shifting fullbridge switching power supply system, it establishes the mathematical model ofphase-shifting full-bridge switching power supply system. It designs the double loopcontroller that the inductance current is inner loop and the voltage is outer ring,combining with Bode diagram, it analyzes dynamic and steady-state performance ofthe controller, Set up a system based on Simulink model, and simulated.3. According to the performance requirements of switching power studied andreduced, it completes the device selection and parameter design of the main circuit,including a three-phase bridge rectifier, filter capacitor, the power switch,DC-blocking capacitor, high-frequency transformer, output rectifier bridge and so on.According to the controller design of the phase-shifted full-bridge switching power, itcompletes PWM phase-shift control circuit, the double closed-loop control circuit thatthe current is inner ring and the voltage is outer loop, and IGBT driver circuit design.It designs the pre-charge circuit and the detection control circuit of the transformerprimary side peak current.4. According to the theoretical analysis and the circuit design, the switchingpower system experimental platform is set up, in this experimental platform, it studieshow to achieve ZVS of the lagging-leg, duty cycle loss, transformer magnetic fluximbalance, switch tube voltage spikes, the output rectifier diode voltage spikes,parasitic oscillation and so on, it analyzes and compares to the experimental result, itshows that it implements zero voltage switching at different input voltages, differentload range, and different duty cycles, it is found that the switching losses is reducedand the switching power supply efficiency is improved. It chooses reasonableresonant inductor to promote the lagging leg to realize ZVS and suppress the dutycycle loss, it is installed blocking capacitor in series at primary side of the transformer to effectively inhibit the flux imbalance.5. On the basis of the experimental platform of switching power supply system,combining with theoretical analysis and experimental research, it produces thephase-shifting full-bridge switching power supply prototype, the field tests show thatits performance meets the requirements of technical indicators.