闭环控制在无刷直流电机系统中的应用

闭环控制在无刷直流电机系统中的应用

　　无刷直流电机因其可靠性高、效率高、噪音低而取代传统的直流电机。这些产品在几乎所有领域都很流行，如消费电子、家用电器和工业控制。高性能无刷直流电机控制系统的开发需要更高的精度。这是通过在大多数BLDC控制系统中使用闭环控制来实现的。

　　无刷直流电机

　　直流无刷电机在直流电机上的优点是：

　　效率高

　　更可靠和无电弧换向-无刷维修

　　更高的速度和功率大小比

　　定子内产生热量-易于去除。

　　低惯量无换向器

　　更高的加速率

　　BLDC motors are more efficient than brushed DC motors. For the same input power， a BLDC motor converts more electrical power into mechanical power than a brushed motor because of the absence of friction due to brushes. In a brushed motor design， the brushes are used to change the poles of the electromagnet in order to keep the motor spinning. Due to this lack of brushes， there is nothing to mechanically handle the polarity changes. As a result， an electronic controller is required to continuously switch the phase of the winding which will keep the motor spinning. To do this， the stator windings are energized in a particular sequence as seen in Figure 1. BLDC motors have three phases. With this topology， to move the motor， two phases are driven during each commutation cycle. One phase is driven high （VMotor） and the other is driven low （GND）。 The remaining phase is left floating. With every commutation step， the motor will move 60 degrees. Upon completion of all cycles， the motor will have moved a complete 360 degrees.