A Vector Selection Based Common Mode Voltage Reduction Strategy for Dual Three Phase Permanent Magnet Synchronous Wind Power Generators Considering Harmonic Suppression

Dual three phase permanent magnet synchronous generators (dual 3-ph PMSGs) have been used as wind power generators increasingly. Lifetime is one of main concerns in wind power applications, especially in offshore farms due to their high maintenance cost. In particular, generator insulation plays a key role in determining lifetime of the overall system. Therefore, reduction of common mode voltage (CMV) through advanced switching pattern generation strategies will have a positive impact on the lifetime. In this paper, a vector selection strategy based on synthetic vector theory is proposed to reduce CMV of a dual 3-ph PMSGs drive system. This strategy is based on finite-set model predictive control (MPC) providing a modified finite voltage vector set which can maintain CMV at a low level. Meanwhile, it can significantly reduce harmonics and maintain a low switching frequency as well. After detailed explanation of this strategy, experimental results validate the performance.