Research Of Digital Dual Switch Forward DC-DC For Vehicle

Compare with analog power, the digital power has many advantages such as flexibility of design,advanced control algorithm, better capability of anti interference. The digital power is taking place ofconventional analog power in advanced applications gradually. The DC-DC converters for electronicvehicles work in terrible environment, they require high convert efficiency, high stability and bettercapability of anti interference, so the study of digital DC-DC converter has practical value.According to the requirement of program, an entire design scheme was proposed. The studycomposed of two parts: the power circuit adopts dual switch forward topology, the detailed workingprocess was analysis. Then the parameters of transformer, filter conductor and filter capacity wascalculated. The drive circuit and startup circuit were designed at the same time; Digital control circuitwas based on FPGA, small signal model was established and then transfer function was deducted. Thesampling circuit uses6bits high speed parallel ADC chip. Indirect method was used to design digitalPID controller. To eliminate integral windup, integral separation method was used. At the same timepipeline algorithm was introduced to speed up operation. Considering of the number of logic elementand clock frequency, delay line count hybrid method was used to implement digital PWM, theresolution is up to10bits.The result indicates that the output voltage is smooth and the ripple ratio is small enough. Theoutput voltage can recover to stable state rapidly when the load or the input voltage changes, and theradiation interference is small. The result proves that the digital power system can meet the demand ofdesign index.