The Design Of Switching Power Supply Based On Active Power Factor Correction And Soft Switch Technology

With the constant development of the electronics industry, the power supply of electronic equipment changes the switching power supply from the initial the line power supply. Switching power supply in the electronics industry plays an increasingly important role in applications in communications, computer, automation, military, industry, agriculture and so on. Therefore, there is growing concern about high-performance switching power supply. Constantly using new techniques to improve the performance of switching power supply is a constant topic.This article, based on understanding of switching power supply in the industry status and research focus, in-depth study of the basic principles of switching power supplies and related technologies and focusing on analysis of the switching power supply power factor correction and phase-shifted full-bridge soft-switching PWM technology, designs a power module with the frequency of 100kHz. Its output voltage is 50V and the output current is 12A. The power module consists of two-stage circuit: power factor correction and DC/DC conversion.Firstly, it gives a comprehensive introduction to kinds of DC/DC conversion circuit, through detailed analysis of the waveform of their principles, In power factor correction, it uses the Boost circuit based on average current control circuit to achieve this function. It makes the special chip UC3854 complete control of the circuit, allowing the input power factor of the circuit to 1 or close to 1 and reducing the harmonic pollution on power circuits. So power becomes more green. In the high frequency of the main inverter circuit, through the PWM switching power supply technology and soft-switching technology research, it chooses the phase shift control of ZVS PWM DC/DC converter as the main power conversion circuit. Because the previous ZVS Phase-shifted soft-switching topology has problem of the duty cycle loss, it uses the improved soft-switching phase-shifted full-bridge PWM converter. Not only it achieves zero-voltage switching tube opening, but also effectively inhibits the duty cycle Loss, reducing the power device losses and improving power efficiency. Upon completion of the design of circuit parameters and the auxiliary circuit design, it uses MATLAB to simulate part of the main power conversion circuit. It shows that the designed circuit is correct. In the main power control module, it chooses the DSP chip TMS320LF2407A type and its peripheral circuitry to form the control circuit, thereby overcoming some shortcomings of the general single-chip controller, such as the limited operating frequency, not high enough and accuracy frequency and not able to complete one cycle control defects. It is easy to achieve digital control of power. Finally, it gives a detailed software design program flow based on phase-shifting digital control scheme.