DC Distribution Converter with Partial Power Processing for LVDC/MVDC Systems

Medium-voltage DC (MVDC) and low-voltage dc (LVDC) grids are regarded as a promising solution for electric shipboard power system (SPS), battery energy storage system (BESS), electric vehicle (EV) charging system, etc. In MVDC system, dc distribution converter (DDC) or dc transformer (DCX) is a crucial component dedicated to interfacing different dc buses. DDC is required to regulate the bus voltage to maintain system reliability and operability. Since the bus voltage variation is usually small, e.g. 10% of the rated bus voltage, input-parallel output-series (IPOS) partial power (PP) converter is suitable for DDC application. This paper proposes an overall design procedure for IPOS PP DDC. Take a shipboard MVDC system as an example, two turns ratio designs are examined. And then, the scalability of PP architectures is analyzed. Finally, the hardware design is conducted with efficiency optimization. The proposed design procedure is verified by an 18 kW 500 kHz PP DDC prototype, achieving 98.8% peak efficiency and 142 W/in(3) power density.

Automated summary

This paper proposes an overall design procedure for input-parallel output-series (IPOS) partial power (PP) converter for use in dc distribution converter (DDC) in medium-voltage DC (MVDC) system. The design process is validated through an 18 kW, 500 kHz PP DDC prototype with 98.8% peak efficiency and 142 W/in(3) power density achieved.