Phase Current Reconstruction Strategy of BLDC Motor in Low Modulation Region Based on a Single Current Sensor

To solve the problem of low current reconstruction accuracy of a brushless DC motor with a single current sensor in a low modulation region, two innovative current reconstruction strategies are proposed in this paper. The traditional space vector pulse width modulation (SVPWM) technique is easy to introduce large errors under the condition of limit modulation. In order to improve the reconstruction accuracy, this study proposed a pulse shift method with compensation, which corrects the voltage error caused by PWM pulse deviation in the compensation area and extends the action time of the basic voltage in the measurement part to ensure that the action time of each voltage vector meets the minimum sampling time. In addition, in order to reduce the loss caused by frequent switching in traditional methods, an ETPWM algorithm is proposed to solve the current reconstruction problem. The algorithm uses three effective vectors to synthesize the required voltage of the motor and inserts zero vectors to optimize the switching action, reduce energy consumption, and improve efficiency. Simulation results show that the two low modulation current reconstruction algorithms proposed in this paper have significant effects in reducing loss, improving system efficiency and performance, and having broad prospects in motor control systems.