Extending the Harmonic Optimization Function of Capacitively Coupled Active Damper for LCL-Equipped High-Speed PMSM Drives

This article extends the harmonic optimization capabilities of capacitively coupled active dampers for LCL-equipped high-speed permanent magnet synchronous drives. The benefit of the proposed approach is that the active damper not only provides resonance damping but also reduces the harmonics of the motor current. The resonant damping loop is implemented by feeding the motor current in series with a high-pass filter. The harmonic optimization loop is implemented by capacitor voltage feedback. Compared with the traditional current-type active damper, the capacitive-coupled active damper has a simpler topology, lower dc voltage stress, lower loss, and simpler control structure. The proposed extended harmonic optimization method has been experimentally demonstrated to reduce the motor current harmonics by approximately 25%.