Control Strategy for Small DC-Link Capacitor Brushless DC Motor Drives Using a Single DC-Link Current Sensor

While employing a single current sensor in a brushless dc motor (BLDCM) drive system can significantly reduce costs, it can also introduce the measurement dead-zone problem. To address this problem, this paper analyzes the relationship between DC-link current and phase current under various voltage vectors in Zone II. This paper employs a single DC-link current sensor (SDCS) to sample the DC-link current and reconstruct the phase currents, with the sampling method being free of measurement dead-zone across the entire speed range. For a BLDCM system, whose DC-link consists of a small capacitor and an insulated gate bipolar transistor (IGBT), this paper proposes a SDCS control strategy. The phase current and the actual speed of the motor are used to determine zone division, ensuring the BLDCM system with small capacitance operates reliably. Experimental results demonstrate the effectiveness of the proposed approach.