Dynamic performance and small-signal analysis of a DC-DC step-up converter with high-gain output rectifier for offshore wind turbines

Abstract

This paper presents the modeling and dynamic analysis of a DC-DC step-up soft switching converter with high-gain high-frequency output rectifier for medium voltage (MV) DC grid for offshore wind energy systems. First, the dynamic model of the converter with duty ratio control is discussed. Then a modified phasor transformation of the circuit is presented for the DC/DC step-up converter with variable frequency control. Analytical expression of the system transfer function is also provided to design the close-loop control system. Simulation results are given to verify the analytical analysis and the equivalent circuit model of the circuit on a 2.5kV/25kV, 500kW converter system.