Current limit strategy for BLDC motor drive with minimized dc-link capacitor

Brushless dc (BLDC) motor drive system employing minimized dc-link capacitor is becoming popular due to compactness and long life. With low capacitance, the dc bus voltage will be pumped up severely if regenerative current flows back, the occurrence of which is common in conventional current limit operation. To avoid the damage caused by oversize pumping-up voltage, a current limit strategy without regenerative current is necessary. This paper proposes a novel current limit strategy for BLDC motor drive with minimized dc-link capacitor. The realization based on single current sensor and software comparison is presented in detail. At last the proposed strategy is verified by simulation and experiment.