Research On Peak Current Controlled Phase-shifted Full-bridge Converter Based On DSP Control

High efficiency and high power density module power supply is widely used in aerospace and other defense and military fields.Based on the current complex international situation,it is urgent to develop a fully domestic module power supply with independent control.In this paper,the input voltage is 200V-400 V,and the output voltage is 28 V / 1k W.The hardware circuit is designed based on the domestic device,and the ADP32F035 digital signal processor is used as the control carrier.The closed-loop control algorithm is designed to improve its dynamic characteristics and improve the conversion efficiency index.The main research contents of this paper are as follows:Firstly,the topology of high-power module power supply is analyzed and compared,and Tr-Lag phase-shifted full-bridge with clamping diode is selected as the research object of this paper.By analyzing the realization conditions of the soft switching of the Tr-Lag phase-shifted full-bridge converter,the dead time is adjusted based on the input voltage and load current,which reduces the switching loss of the primary side and improves the operating efficiency of the converter.Based on the analysis of the switch loss model of the converter,a pulse skipping mode control is proposed to reduce the loss of the converter under extremely light load conditions.Three rectification timing control strategies are designed for the load partition,which greatly reduces the loss of the output stage rectifier and ensures the high efficiency operation of the converter under wide load conditions.Secondly,through the analysis of the dynamic model of the converter,the peak current control is selected as the closed-loop control scheme of the phase-shifted full-bridge converter.The comparator module in the ADP32F035 digital signal processor is used to realize the position and reset of the peak current to the primary side switch tube.The implementation method is simple and the dynamic response speed is fast.The ADP32F035 digital programmable ramp generator is used to compensate the current,which eliminates the sub-harmonic oscillation of the converter.In order to enhance its dynamic response capability,the voltage outer loop adopts a fourth-order analog compensation network.Then,the hardware circuit of Tr-Lag phase-shifted full-bridge converter is designed in detail,including power circuit design,control circuit design and auxiliary power supply circuit design.Through the localization selection of the device,the full localization development of the module power supply is realized.Based on the above hardware circuit,the software control algorithm is designed to realize the above timing optimization control strategy.Finally,the experimental prototype with high power density is developed.Based on the designed experimental prototype,the key waveform test and efficiency test are carried out.The dynamic performance and efficiency of the prototype meet the design goals.The results verify the correctness of the theoretical analysis and the effectiveness of the timing optimization control strategy.