Składowa zerowa pradu w układzie elektrowni wiatrowej z generatorem synchronicznym z magnesami trwałymi

In the rotating electrical machines working with transistorized converters common mode (CM) voltage current appears. The reasons of the CM voltage appearing are inner properties of the transistors control algorithms. When the CM voltage exists the CM current can flow through parasitic capacitance of the electrical machines and converters. Part of that current flows through motor bearing and strongly decreases bearing life. Example of power electronics drive is wind generator system. In the wind generator system two converters are used: machine inverter and grid inverter. In the presented system the permanent magnet synchronous generator (PMSG) was used. For PMSG efficient control the position of the rotor should be known. In the realized drive to eliminate position sensors the sensorless control method was implemented. During realization of the sensorless control the problem with the measurements of the machine voltage appeared. The measured voltage was strongly disturbed by flow of the common mode current. To solve that problem the path the high impedance for CM path was inserted. Two solutions: zero component choke and three-phase transformer applied between the generator drive system and the electric grid were tested. In the paper the CM voltage theory is presented. The results of the experimental investigations are presented.