Development of controllers for renewable energy conversion systems with power quality improvement

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Wind energy, due to its free availability and clean and renewable character, ranks as the most promising energy resource that could play a key role in solving the world energy crisis. According to Canada Wind Energy Association (CWEA), Canada's wind energy industry has already broken its annual growth record in 2009 with 950 MW of new wind energy capacity, with a total capacity of 3499 MW till September 2010. The CWEA in its 'WindVision 2025' document sets a goal of producing 20% or more of the country's electricity from wind power by 2025. Due to significantly higher and more constant wind speeds, reduced planning restrictions, and the shortage of suitable sites for wind farms on the land, off-shore wind farms are becoming very attractive. Europe has held the lead in off-shore wind, having installed more than 830 turbines with grid connections to nine European countries. Canada has also started investing in off-shore wind farms with many projects in line. To transit such bulk power over great distances, in sea, creates challenges for both system operators and wind farm developers, apart from inherent wind's intermittent nature. From the off-shore collection point to on-shore grid, VSC-HVDC technology has many advantages over other transmission links such as, HVAC or HVDC with thyristor-based line-commutated converters (LCC). It is becoming more and more important to develop advanced control techniques so that the integration of off-shore wind farms with the on-shore grid is more reliable, efficient and free from power quality problems. Therefore, the objectives of the proposed research work is 1) to conceive, analyze/evaluate, fabricate/test proper converter/inverter topology and its control for VSC HVDC system (simulated on a real-time digital simulator - RTDS), for various types of off-shore wind farms. 2) to simulate an on-shore power system network on a RTDS. 3) to develop proper control techniques to integrate off-shore wind farms (of objective 1) with an on-shore power system network (of objective 2). 4) Performance evaluations of integrated off-shore wind farms and on-shore power network for various operating conditions.