영구자석형 풍력발전 시스템의 3병렬 설계와 계통연계 기술
The design of Three-Parallel System for High-Power Wind Turbines using a PMSG
- 주제(키워드) 풍력발전기 , 영구자석형동기발전기 , 3병렬시스템 , LCL필터 , 공진보상 , 계통연계기술
- 발행기관 아주대학교
- 지도교수 이교범
- 발행년도 2010
- 학위수여년월 2010. 8
- 학위명 석사
- 학과 및 전공 일반대학원 전자공학과
- 실제URI http://www.dcollection.net/handler/ajou/000000011004
- 본문언어 한국어
- 저작권 아주대학교 논문은 저작권에 의해 보호받습니다.
초록/요약
The demand of power conversion system for the purpose of a variable speed control is increasing in the wind power system. The PMSG (Permanent Magnet Synchronous Generator) has advantages of a wide range of wind speed and an easier control scheme, compared to a DFIG (Doubly Fed Induction Generator). Switches and filters, however, need to be selected regarding the overall system rating because the power conversion part is directly connected between a generator and a grid. The rated current of the power devices can be reduced to one third value under the three-parallel operation. However, it is required that the inductors of the each leg are appropriately designed to avoid the circulating currents and the three-parallel operation is controlled by proper controllers. The THD (Total Harmonics Distortion) reduction of output currents and power quality regulation are important in the grid connection system. The inductance of the input or output circuits of the power conversion devices have conventionally been used to reduce these harmonics. However, as the capacity of the systems have been increasing, high values of inductances are needed, so that realizing practical filters has been becoming an ever more difficult due to the price rises and the poor dynamic responses. These problems, caused by realizing practical L-filters in large-scale facilities can be solved by using LCL-filters [2-5]. This is expected because an additional LC part can reduce the harmonics effectively in several hundreds of kVA. Moreover, an LCL-filter realization is easy and effective, with little increase in overall system cost and without having to introduce additional sensors. However, unless all of the filter’s parameters are properly selected, it is not possible to achieve effective reduction of the harmonics, and the additional resonance poles caused by the second LC part can further raise the stability problems. There are two solutions to this situation, namely, 1) introduce passive damping by adding a resistor connected to the parallel capacitor, and 2) introduce active damping where no additional resistor is needed. Passive damping is simply a way to guarantee the stability of the system, but there is additional loss caused by the added resistance. To avoid such losses, papers relating to active damping algorithms that are aimed at resolve the stability problems without additional resistors, have been announced. But these algorisms require additional voltage sensor, exact tuning of gains or filter parameters. This paper proposes the compensation method using power theory which has implementional advantages because it is simple and realizable without the need for an additional sensor and exact tuning of gains or filter parameters. In this paper, the system design and Grid-connection technique for high-power wind turbines using PMSG are proposed. The simulation results verify the proposed system and methods.
more목차
제 1 장 서론 1
제 2 장 풍력발전 시스템 4
2.1 블레이드 모델링 4
2.2 발전기 측 컨버터 제어 6
2.2.1 토크 제어기 6
2.2.2 최대 출력점 추종 제어 7
2.2.3 전류 제어기 8
2.3 계통 측 인버터 제어 11
2.3.1 계통 측 인버터의 동기 위상각 계산 12
2.3.2 IP제어기 15
2.3.3 전류 제어기 17
제 3 장 3병렬 시스템 설계 18
3.1 계통 측 인버터 설계 18
3.2 발전기 측 컨버터 설계 22
제 4 장 계통연계 기술 25
4.1 3병렬 풍력발전시스템의 필터 설계 25
4.2 LCL필터의 공진 보상을 위한 능동댐핑 기술 29
4.2.1 전력이론(P-Q이론) 31
4.2.2 공진 보상 32
제 5 장 시뮬레이션 34
5.1 LCL필터의 공진보상 36
5.2 전체시스템의 제어 38
제 6 장 실험 43
제 7 장 결론 및 요약 48
참고문헌 49
