Dual-mode control strategy based on DC-bus voltage for dual-active bridge converter in marine electromagnetic transmitter system

The marine electromagnetic detection method is the main method for the exploration of marine oil and gas resources. At present, the controlled source circuit of the electromagnetic transmitter is a unidirectional flow of electric energy. When the emission electrodes release the stored energy, the energy cannot be fed back, resulting in an increased DC bus and switch device voltages. The stress increases and the filter capacitors and switch devices are burned, which cannot guarantee the long-term reliable operation of the underwater devices body in the deep sea. A dual-active bridge converter is presented for the controlled source circuit of the electromagnetic transmitter. First, the topology, operating principle, and soft-switching constraints are introduced in detail. Then, a dual-mode control strategy is designed. The inductor current stress optimization control is adopted to ensure a steady-state operation, and the univariate extended phase-shifting sliding mode control is applied to achieve fast energy feedback of the inductive load. Simulation and experimental results show that the proposed circuit significantly reduces the bus voltage effect and switch device voltage stress, improves the efficiency and dynamic performance of the system, and satisfies the needs of deep-sea oil and gas resource exploration.