Modeling of dual-active soft-switching converter for MTEM transmitter

Abstract

Multi-channel transient electromagnetic (MTEM) is an artificial source electromagnetic detection method, the transmitter injects the high-power pseudo-random binary sequence (PRBS) signals with different coding frequencies into the earth to obtain the geological structure and the mineral resources. However, the current transmitters have many problems, such as small power-density, low efficiency, and poor quality output signals. A novel dual-active soft-switching converter can significantly reduce the circuit loss and achieve stable output from nearly zero to full load. Because of the proposed converter containing 18 operating modes in a duty cycle, it cannot be directly modeled. Based on the model of the full-bridge hard-switching converter, the steady-state and low-frequency small-signal model of the proposed converter is established by analyzing the influences of resonant inductance, input voltage and output current fluctuations on the effective duty cycle. Finally, the simulation and experimental results verify the validity of the model, and a 50kW principle prototype is implemented.