A Series Resonant DC/DC Converter With Certain DC Voltage Gain Adjustment Capability for Renewable Energy MVdc Collection

Medium voltage direct current (MVDC) collection is a promising approach for integration of large-scale renewables. This paper proposes a series resonant DC/DC converter for MVDC collection with certain DC voltage gain adjustment capability. By adding an auxiliary half-bridge and a low-insulation-level auxiliary transformer to the traditional series resonant DC/DC converter, the proposed converter allows flexible voltage gain adjustment. All semiconductor devices in the system can achieve soft switching over the entire voltage and power range, resulting in high operation efficiency. The analysis includes a detailed examination of the plane trajectory to assess device stresses, voltage gain, and design methods for resonant parameters. Simulation results validate the proposed approach, and the experimental results from a scaled down prototype further proves the effectiveness.