四开关三相无刷直流电机的直接电流控制

在回顾传统六开关三相无刷直流电机（BLDCM）基本工作原理的基础上，从简化逆变器拓扑结构，降低BLDCM系统成本的角度出发，分析了用四开关逆变器驱动三相BLDCM的工程可行性。针对四开关逆变器固有的非对称电压矢量问题，提出了四开关三相BLDCM的直接电流控制策略。该方法将系统整个工作过程划分为6种工作模式（模式1~模式6）。并对四只功率器件的关断和导通次序作了全新安排，采用滞环控制直接产生驱动BLDCM所需的相电流波形。并且指出在模式1和模式4两种特殊工作状态下，可以通过相电流的独立检测、独立控制，来对非工作相的反电动势效应进行补偿，抑制工作相相电流的畸变。为了验证方案的可行性，设计了具体的实验系统。最终的实验结果表明了控制策略的正确性和有效性。

A Novel Direct Current Control of Four-Switch Three-Phase Brushless DC Motor

Reviewing the traditional six-switch three-phase brushless dc motor(BLDCM), the paper analyzed the engineering feasibility of driving three-phase BLDCM by four-switch converter, in order to simplify the converter topology and lower the system cost. A novel direct current control scheme was put forward to deal with the inherent asymmetric voltage vectors of four-switch converter. The system's whole working process was divided up into six operating-modes(Mode1~Mode6). The conducting sequence of four power switches were rearranged and the phase current was shaped directly by hysteresis controller. In Mode1 and Mode4, the two off-order operating-modes, the currents of different active phases were sensed and controlled independently, to compensate the silent phase's EMF effect and suppress the conducting phase's current distortion. An experiment system was built to verify the correctness of the plan. The results reveal the validity and reliability of the scheme.