High Power Dc-Dc Converter Based on Parallel Hybrid Converter

The parallel hybrid converter (PHC) is gaining popularity for high voltage direct current applications. The chain-links (CLs) in the PHC bear only a fraction of the output phase current and exhibit double frequency nature. This reduces the energy storage requirement and the losses occurring in the CLs of the PHC. The PHC converter also requires lower number of sub-modules (SMs) and switching devices. The existing PHC configuration requires harmonic voltage injection in the CLs to feed the ac grid, thereby injecting harmonic currents into the main DC-link and it is not dc fault-tolerant. A new front-front dc-dc hybrid configuration for high voltage transmission systems using PHC is presented, which eliminates the need for harmonic voltage injection. The proposed dc-dc configuration is dc fault-tolerant and requires reduced SM capacitors size and smaller interlinking transformers owing to high-frequency switching operation. The authenticity of the proposed dc-dc converter is verified by caring out various simulation and hardware studies.