295 Agronomy Research 11 (2), 295–306, 2013 PMSG based residential wind turbines: possibilities and challenges L. Bisenieks 1, *, D. Vinnikov 2 and I. Galkin 1 1 Institute of Industrial Electronics and Electrical Engineering, Riga Technical University, Kronvalda Blvd. 1, LV-1010 Riga, Latvia; * Correspondence: lauris.bisenieks@rtu.lv 2 Department of Electrical Drives and Power Electronics, Tallinn University of Technology, Ehitajate tee 5, EE19086 Tallinn, Estonia Abstract. This paper presents an overview of technologies for wind energy conversion into electrical energy with the help of residential wind turbines. The theory of wind energy conversion into mechanical energy is shown. Wind velocity distribution and normalised energy yield examples are given to improve understanding of wind energy availability and converter operation modes. Additionally the wind velocity dependency of the height above ground is explained. The pros and cons of wind turbine generators are analysed. Converter topologies galvanically isolated for interfacing a permanent magnet synchronous generator based variable speed wind turbine with a residential power network is analysed. Main emphasis is on the combination of a rectifier and an isolated quasi-Z-source (qZS) based DC/DC converter topology proposed by the authors. The topology (rectifier coupled with a qZS based galvanically isolated step-up DC/DC converter) is essential to generate regulated DC voltage (400 V DC typical for 230 V AC output) despite wide variations in the output voltage of a wind generator. The operation principle of the proposed topology is described. Experimental and simulation results are presented and analysed. Key words: Renewable energy, power converter, wind turbine. INTRODUCTION Continuous growth of the earth’s population and standard of living leads to stable growth in energy consumption. Limited availability of fossil energy resources urges us to make use of renewable sources for electric energy generation. Wind energy is quite an attractive form of renewable energy especially at high latitudes where the feasibility of applying direct solar energy conversion technologies is limited. The commercial potential of wind energy (72 TW) is five times higher than world energy demand in all forms. However, the installed capacity in the middle of 2012 was only 254 GW (Archer & Jacobson, 2005; World…, 2012). Wind turbines are the most popular wind energy conversion technology today. The power of installed windmills is being increased continuously especially when the places of turbine installation move from on-shore to off-shore. Although the energy yield is higher for large inland and off- shore installations, the issue of transmission and distribution losses is still of major concern. Distributed generation and smart grid technologies are introduced to reduce