Improved Digital Average Voltage Control for Switching Converter with Capacitor Current Compensation

Taking a buck converter in continuous conduction mode as an example, the improved digital average voltage (IDAV) control technique with capacitor current compensation is presented, and the operation principle and control law are analyzed in detail. The stability and transient performance impacted by the compensation coefficient are investigated by sampled-data modeling, and the optimal compensation coefficient for the fastest load transient performance is found. The analysis results show that the compensation coefficient can be regarded as a virtual equivalent series resistor (ESR) of the capacitor, which affects the stability and transient performance of the system without increasing output voltage ripple. Experimental results are given to verify the correctness of the theoretical analysis.