| The latest development trend of the power system is that paralleling the high-performancepower modules to achieve high power output. The paralleling operation of the power supplywhich is the key to achieve high-power system, is the direction of power technology, and it isalso an effective way to achieve modular and large capacity. Paralleling multiple power modulesinsures evenly distribution of the load, and it also reduces the current stress on the main powerswitch devices and meet the requirements in terms of performance、weight、volume、efficiencyand reliability of large-capacity power supply.In this paper, the working frequency of full-bridge DC/DC power module is up to200KHz, which causes much switching losses, so the soft-switching technology is proposed. Thepaper focuses on working principle of phase shift controlled full-bridge soft switching DC/DCconverter and the difficulties about how to achieve. Considering the low voltage and high currentoutput of the secondary-side rectifier circuit which severely limits the efficiency of the converter,synchronous rectification is proposed. The12V/50A DC/DC power modules designed based onthe master chip UCC28950achieves soft switching of the inverter circuit, it also achievessynchronous rectifier of the secondary side. Soft-switching technology and the application ofsynchronous rectification technology greatly improves the efficiency of the power supply, whichreduces the size and weight of the power supply module.By analyzing various flow control method, maximum current flow method is selected toachieve uniform distribution of load current. Take parallel system that consists of two powersupply modules for example, the current control circuit is designed by using current control chipUC3907corresponding, which achieves the uniform distribution of current effectively.Finally, simulate the hardware circuit by using PSPICE software and give the current dataof the prototype test results of the two paralleling power supplies. |
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