The MMC converter is the key topology for HVDC applications. In these systems, a major complexity is the number of modules and components required per phase to achieve nominal voltage and current levels for applications in transmission system. In this paper, the topology and control of a two-phase MMC system for HVDC applications is presented. The main idea is to eliminate a complete phase of the classic MMC converter for reduce the number of modules and the complexity of the system, together with the use of MMSPC-type modules, in order to achieve internal voltage balance without the need of extra sensors and control loops.@en

The Hexagonal power converter has become a suitable solution to provide high-quality voltage waveforms while achieving decoupled control of three DC terminals as well. In this case, the internal voltage balance of the different storage units is the main concern for the correct operation of the Hexagonal converter. Moreover, the Modular multilevel series- parallel converters (MMSPC) have become an interesting solution to provide higher operating voltages, reliability at a reduced cost, due to their ability to achieve a simpler internal voltage balance. In this paper, a Hexagonal power converter based on MMSPC for decoupled DC terminals is presented. The proposed system allows to implement a simple and cost-effective way to achieve a decoupled control strategy in each output of the system, to control the corresponding voltage of the system, along with maintaining the internal voltage balance of the proposed topology.@en

Increasing the power rating of electric vehicles (EV) fast charging stations to reduce charging times is considered critical to accelerate the adoption of electric vehicles. Besides increasing the power, other drivers pushing the development of EV fast chargers include the improvement of efficiency and reliability. Partial power converters (PPC) have emerged as an interesting option for some of the power converter stages in fast charging stations due to their potential to increase efficiency and power rating. However, some PPCs operate as switched autotransformers by using high frequency (HF) isolation transformers but without providing galvanic isolation. This is a drawback due to cost, size and losses introduced by the transformer. This paper presents a transformerless DC–DC Type I step-up PPC for a DC–DC regulation converter for EV fast charging stations. The proposed converter replaces the transformer commonly used in Type I PPC by an impedance network, resulting in a more efficient, cheaper, and less complex converter option. This concept is verified through simulations and experimentally validated with a laboratory prototype.@en