풍력발전시스템의 전력변환부 3병렬 운전을 위한 LCL-필터 설계
Design of an LCL-Filter for the Three-Parallel Operation of a Power Converter in Wind Turbines
초록/요약
Permanent Magnet Synchronous Generators (PMSG) are widely used in variable-speed wind turbines. However, the power devices must support high currents to get their high-power rating because the PMSG is connected directly to the grid through a back-to-back converter. Therefore, the rated current of the power device can be reduced to one third of the rated value by using a three-parallel operation. The low switching frequency of a high power system may cause an increase in the harmonics found in the output current. This paper proposes a design scheme for an LCL-filter used for three-parallel operation of a power converter in 2MW-wind turbines. An appropriate design method of the delta configured LCL-filter is also proposed to improve the output power quality in the system. A novel design method for the inner inductance of the LCL-filter is proposed in order to overcome the existing trial and error methods used in designing the filter. LCL-filters typically have a problem with a reduced power factor (PF), due to the capacitor used. To improve the poor PF, a simple compensation method is also proposed. The simulation and experimental results demonstrate that the grid current harmonics are low and the PF is improved.
more목차
제 1 장 서론 1
제 2 장 영구자석형 풍력발전시스템 4
2.1 블레이드 모델링 4
2.2 최대 출력점 추종 제어(MPPT) 5
2.3 DC링크 전압 제어 7
2.4 3병렬 운전을 위한 제어방법 8
제 3 장 델타 LCL-필터 설계 10
3.1 3병렬 전력변환부에 연결된 필터의 구조 10
3.2 쉐어링 인덕턴스 설계 11
3.3 내부인덕턴스 설계 12
3.4 Y결선된 커패시터의 설계 21
3.5 외부인덕턴스의 설계 22
3.6 댐핑 저항 계산 23
3.7 역률 보상 23
제 4 장 시뮬레이션 25
제 5 장 실험 34
제 6 장 결론 및 요약 41
참고문헌 42
