넓은 입·출력 전압 사양의 수소연료전��-배터리 기반 철도차량용 고밀도 절연 승압형 DC-DC 컨버터에 관한 연구 (Study on High-Power-Density Isolated Step-Up DC-DC Power Converter for Hydrogen-Fuel-Cell and Battery Railway System with Wide Input and Output Range)

최근 에너지 효율이 높은 수소연료전��왿� 배터리 기반의 하이브리드 철도차량용 추진시스템이 주목받고 있다.
수소연료전��는 높은 가격으로 인해 견인전동기 구동을 위한 인버터의 높은  DC 전압을 직접적으로 공급하기 어려우므로, 낮은 전압을 갖는 수소연료전��왿� 인버터 사이에 승압형  DC/DC 컨버터가 필요하다. 그러나 수소연료전�� 기반 하이브리드  철도  시스템은  추가적으로  부피를  차지하는  수소연료전��왿�  배터리로  인해  기존  가선  기반의  철도  시스템에 비해 더 제한 된 공간 및 중량이 요구 된다. 이러한 제약으로 인해 승압형 추진  DC/DC 컨버터는 더 높은 전력 밀도왿� 경량화가  요구  된다.  본  논��에서는  수소연료전��왿�  배터리  기반의  하이브리드  철도차량용  추진시스템을  소개하고,  다양한 분석을 통해 높은 전력 밀도왿� 경량화에 적합한 기존 승압형 셚버터를 검토한다. 또한 승압형 셚버터로써, 높은 전력 밀도왿� 경량화를 달성할 수 있는 인터리빙 제어 기반의  ‘입력 병렬, 직렬 출력 구조의 공진형  LLC 컨버터왿�  3-Level 벅-컨버터가 결합 된  2단 구조의 모듈형 컨버터’를 제안한다. 동작 모드, 설계에 필요한 전압, 전류 리플 분석을 통해 설계 된 제안하는 컨버터의 효율 및 부피를 기존 컨버터왿� 이론적으로 비교하고, 제안하는 컨버터의 설계를  PSIM 시뮬레 이션을  통해  검증하였다.

Recently, a railway propulsion system based on an energy-efficient hydrogen-fuel-cell and battery has attracted attention. Because hydrogen fuel cells have difficulty supplying high DC voltage to the inverter to drive the traction motor, resulting in a expensive price, a step-up DC/DC converter is required between the hydrogen fuel cells with low DC voltage and the inverter. However, a hydrogen-fuel-cell hybrid railway system has more limited space and weight compared with a general railway system, due to additional space for the hydrogen fuel cell and battery. Thus, a step-up DC/DC converter with high power density and light weight is required. This paper describes the structure of a propulsion system for a hydrogen fuel cell hybrid railway system and reviews step-up DC/DC converters suitable for high power density and light weight systems through various types of analysis. By selecting an interleaving control and combination resonant LLC and 3-level buck converters with ‘parallel-input, series-output, and modular structure’ as step-up DC/DC converters, a new DC/DC converter suitable for high power density and light weight devices is proposed through operation analysis, ripple analysis of input current/output voltage, and analysis of design, efficiency, and volume. Finally, overall operation and parameter design are verified by PSIM simulation.