Research On High-frequency Switching Communication Power Supply Based On Dsp

Communication high frequency switching power supply system has the advantages of high efficiency, high power density, small size, light weight, high precision and high power factor regulator. It has been basically completely replaced the original phase-controlled power supply system as the basis power supply equipment for modern communication power system. This paper mainly analysis and design high frequency switching rectifier with the output 48V/30A by digital controlling method which is one kind of direct current communication system often used.The diode rectifier is usually used in the input side rectifier of communication switching power supply, it injects a large number of harmonics to grid, and causes a certain amount of power "pollution". The way to solve the harmonic pollution is to increase the Power Factor Correction circuit. However, dynamic response of this circuit is slow; the controlling circuit is complicated and costly. If a matching PFC circuit is increased for AC-DC switching converter, the cost of whole circuit will increase a lot.We usually use phase-shifted full-bridge soft-switching technology in the DC-DC power conversion part, but there is the phenomenon of circuit vice-side loss of duty cycle and the maximum duty cycle being exploited not fully. To solve these problems, through the research and analysis of communication switching power supply principles, this paper proposes using a single-phase PWM rectifier circuit with a notch filter as a high power factor circuit of input rectifier side and using the direct current controling strategy based on a fixed switching frequency, combined the outer voltage and inner current loop, achieves high power factor of the input side rectifier, fast dynamic response and stable of DC output voltage; using an improved digital control of phase-shifted full-bridge ZVS PWM DC / DC converter as DC-DC power conversion circuit of the power, increasing an auxiliary resonant network in the lagging arm, making power switch of circuit conduct in the zero-voltage state, solving the missing phenomenon of duty-cycle effectly, reducing the switching loss and improving the power conversion efficiency.In the design of high power factor rectifier and DC-DC power conversion circuit, this paper has analysised the calculation and selection of major components,designed the control circuit of high-frequency switching power supply, drive circuit and the sampling circuit. This paper uses Matlab6.5/simulink to simulate PWM rectifier and DC-DC power conversion circuit, the results of simulation and experimental verify the correctness and validity of theoretical analysis.