DC-Link Capacitor Ripple Current Suppression Strategy Based on Harmonic Injection for PMSM Drives

In order to extend the lifetime of DC-link capacitors, a DC-link capacitor ripple current suppression strategy based on harmonic injection for permanent magnet synchronous motor drives is proposed. Analyzing the ripple characteristics of capacitor current and adopting the duty cycle feedforward control strategy to reduce the current controller burden. On this basis, the capacitor ripple current is suppressed by injecting odd harmonics at the grid side and the amplitudes of the injected harmonics are determined to minimize the RMS value of the capacitor current by the optimization calculation. The effectiveness of the suppression strategy was verified on the 1.5 kW air conditioning experimental platform.