Design of Current Buck Converter Based on Frequency Domain Analysis

DC/DC converters working in current mode are widely used. However, the complexity of the loop design for these converters is high (double-loop control system). The small signal model of the Buck converter in average current mode is established, and the transfer function for duty cycle to output is deduced. Based on the analysis of the stability for the converter, appropriate current loop compensation and voltage loop compensation are designed. The correctness of the designed control loop is verified with simulations from MATLAB and PSIM in frequency domain and time domain. The proposed method in frequency domain has certain reference value for control loop design in switching power supplies.