A ∼99% η Hybrid Resonant/Coupled ZCS-Voltage-Quadruplers MV SiC Converter Module for DC Grid in Wind Systems.

In this article, a hybrid high voltage gain converter module for medium voltage dc conversion in wind energy systems is proposed. The converter consists of step-up resonant circuit with coupled voltage-quadruplers to achieve the step-up voltage conversion function. The coupled voltage-quadrupler modules are connected to the resonant circuit via a 1:1:1 high frequency transformer. As a result, high turns ratio transformers are not required in the proposed design while at the same time, the output voltage of each voltage-quadrupler is well balanced due to the shared coupled-inductor. All the primary side silicon carbide (SiC) MOSFETs and secondary side SiC diodes exhibit zero switching losses. The output voltage of the converter module is controlled with variable frequency control. Simulation results on a 4 MW modular design of SiC-based converter system with 3.3 kV/18 kV, 670 kW per module, and experimental results on a laboratory-scale prototype with per-module rating: 500 V/2.7 kV, 3.7 kW are provided to validate the theoretical analysis and to highlight the merits of the proposed work. Results confirmed that a peak efficiency of close to 99% is achieved in both simulation and experimental works. [ABSTRACT FROM AUTHOR]