Research On Digital Current-sharing Technology Of Parallel DC/DC Converter Based On DSP

With the development of power electronics technology, high power and high current electronic devices have become an inevitable trend of power system requirements. High power output can be achieved by using multiple power supply modules in parallel can achieve. Current sharing technology is the core of the parallel power modules for even distribution of the load current. The parallel current sharing technology is gradually substituted by Digital Current Sharing Technique with the advantages of low cost, flexible control, versatility and simple hardware circuit. And is has a significant meaning for the digital sharing technology to achieve parallel power supply.The development of parallel DC / DC converter digital current sharing technology, research profiles and the significance are discussed. The advantages and disadvantages of the flow control method are summarized in the same. Finally, the maximum current flow method to control parallel Buck power module is selected and the composition, theory, small-signal model and simulation PSIM are specified.According to the maximum current automatic sharing technology control model, the sampling current is amplified by using the high-precision instrument amplifier INA128, and it is convertered to digital signal by ADC module in the DSP, then it is loaded into CAN module and sent to the buses. The bus data is received by each module, and it is decoded and compared by the DSP, and the maximum current is sent to the bus. At the same time, the module receives the bus with its own current value for error, and the error amount is applied to the reference voltage, the output voltage of each module is sampled and compared with the reference voltage, and the error increment is sent to the PI regulator to adjust the open of ePWM value module CMPR control MOS tube, a stable output voltage and parallel current sharing of the parallel Buck supply system is achieved, the digital current sharing experiments of paralleled Buck converter is completed.The experimental data and output voltage, current and waveform Vds of MOS pipe are analyzed, it can be seen that the digital current sharing can be achieved by a parallel Buck power supply system, and TMS320F28035 is used as the core for the converter, and imbalance experimental system is less than 5%. The desired technical indicators are achieved.