Series IGBT Chopping Strategy Based on SVPWM for PMSM Drives With Small DC-Link Capacitance

In this letter, a series insulated-gate bipolar transistor (IGBT) chopping strategy based on space vector pulsewidth modulation (SVPWM) is proposed for a permanent magnet synchronous motor drive system with small dc-link capacitance and IGBT connected at the dc link. Based on the maximum output capability of the SVPWM technique, this letter clarifies the minimum dc-link voltage constraint based on the voltage vector angle and proposes a series IGBT chopping strategy that ensures the dc-link voltage always satisfies this constraint. The small capacitor cut into the dc link by turning on the series IGBT for only a portion of each rectification cycle, thereby the required capacitance can be reduced. Simultaneously, the normal operation of the drive system can still be guaranteed. The effectiveness of the proposed strategy is validated through experimental results.