Research Of High-frequency Communications Power Supply Based On DSP

Switching Power Supply for communication is a center in communication Equipment. It has incomparable importance in the communication station. With the rapid development of communications and the constantly updated of communications equipment, the requirements of the power supply for modern communications technology is increasing. High efficiency, high frequency, modular, digital will be future direction of the development in communication power supply. In this paper, against bottlenecks of the traditional analog control switching power supply, we will study about digital control based DSP of high frequency and high efficiency switching power supply, Expect we can design a more stable and smaller,more efficient DC power supply for practical applications.Firstly, through the analysis of the main circuit and working principle about high-frequency switching power supply, research the EMI Problems of input and output about switching power supply, especially, we analyzed the power factor correction and phase shift full-bridge soft-switching PWM techniques in detail about switching power supply. Secondly, we will design a 48V/25A high frequency communication switching power supply, switching frequency is 100 KHz. It includes power factor correction and DC-DC transformation circuit. Control circuit using DSP F2812 generated digital PWM waveform,it drive Mosfets of the main circuit and power factor correction circuit by the isolated pulse transformer, In the power factor correction circuit we use the average current-mode Boost-PFC circuit, including the main circuit, auxiliary circuit, control loop designing. Then we have a MATLAB simulation analysis of Power factor correction circuit. In the DC-DC converter we adopte full-bridge phase-shifting ZVS control serve as the main converter circuit. Through the analysis of the phase shift control full-bridge converter's working principle, face duty cycle loss on secondary side in the Phase-shift full-bridge converter, we decide retain series resonant inductor in the High-frequency transformer primary side and add a auxiliary resonant network in the lagging leg of Phase Shift Full Bridge Converter. So it will achieve ZVS in leading mosfet and lagging mosfet. Then we use Pspice software to finish simulation analysis on the main circuit design. At last, through study of parallel current sharing for power switch supply, aim at the problems for the commonly used average current automatic current sharing, we propose a practical average current automatic current sharing circuit combined with the control circuit.In this thesis, the main line is power supply design, based on the detailed analysis of the circuit principle, we finished design about the main circuit parameters of the system, auxiliary circuit, control circuit and simulation. Finally I confirmed that my proposed methods is effective and feasible.