Study On Soft Switch Power Supply With High Power Factor

With the rapid development of electronic information technology, the power supply has been achieved in many of the achievements and progress. The switching power supply have gradually replaced the linear power supply because of its high performance and efficiency,it plays a particularly important role in today's electronic industry. In the switching power supply indicators, performance indicators largely affect the energy consumption level and equipment power efficiency. Therefore, to find effective methods to improve the performance of switching power supply is a topic which cannot be ignored.First, this thesis introduces the development of switching power supply and the two important technologies to improve the performance of switching power supply: one is the power factor correction technology, the other is the soft switch technology;Second, analyzes the working principle and control strategy of the before and after system levels in detail and provides the concrete design plan. The before level is active power factor correction circuit,after analyzing the control method of the frontend circuit,select the one-cycle control method as the front-end control strategy; The after level is phase-shift full-bridge soft switch DC/DC circuit, choose the full-bridge circuit whose lag bridge arms have series diode zero voltage switch and zero current switch( ZVZCS) as the topology structure. On the analysis of the working principle of full-bridge soft switch ZVZCS circuit and the whole bridge circuit can realize advanced bridge arm zero voltage switch( ZVS) and lag bridge arm zero current switch( ZCS) conditions, select the more precise average current control mode as the control strategy of after level circuit. After the Matlab simulation research of before and after levels, accomplish the system hardware circuit and software program design; Design a kind of soft switch power supply with high power factor whose output voltage and current is100V/10 A.Chip TMS320F2812 is used to realize onecycle and the average current control, and control the switch tube shut offs in the circuit; Compared with the special analog chips such as controller, the controller has obvious advantages in the flexibility of the algorithm.Finally, finish the hardware structures work of the before and after levels circuit, the result of the experiment shows that the power factor of the supply complys with the design requirements, the advanced arm and the lagged arm realize zero voltage switch and zero current switch in full load range, achieve the purpose of improving power performance.