A general digital PID controller based on PWM for buck converter

Based on the function of high performance DSP analog-digital converter (ADC) and pulse width modulator (PWM), a general digital PID control Buck converter is designed. Based on design of main circuit, the basic principle of PID control algorithm based on PWM is discussed in detail. Through the analysis of the PWM generation mode by DSP and PID control algorithm, a universal digital PID controller is designed. Then a prototype of digital control Buck converter based on PWM is constructed. On one hand, static tests showed that static value of the output voltage changes very little in the presence of input voltage and load change of Buck converter. On the other hand, dynamic tests showed that its output voltage fluctuation peak is small when Buck converter input voltage and load fast changes, and can recover quickly. Experiments showed that the proposed system is high accuracy, fast dynamic response and robustness.