A Simple Switching-Event Dependent High-Frequency Sampling Method for Power Conversion System

Precise current and voltage sensing are challenging for digital control in high-frequency power conversion systems. Given that the power electronics circuitry is triggered repetitively by power device switching events, a switching-time-dependent sampling method is proposed to realize an equivalent high-frequency signal sampling with a low-speed analog digital converter (ADC) and digital controller. Two sampling modes are developed in the proposed methods in terms of sampling rates lower and higher than the digital controller clock frequency, respectively. A fast and simple signal reconstruction method is designed to ensure the feasibility of a low-cost processor. A series-resonant dual-active-bridge is taken as an example for the theoretical analysis and experimental verification. The resonant current and Miller plateau voltage in the topology are sampled to verify the potential of the proposed method for online parameter recognition of dc–dc converters and device behavior monitoring of power devices.