Direct Torque Control of Bldc Motor Using Fuzzy Logic in Labview

Brushless dc motors are widely used in many industrial applications due to their high efficiency, high power density and ease of control. In this paper, sensorless direct torque control (DTC) of bldc motor is implemented using fuzzy logic. In actual DTC both torque and stator flux linkage is controlled. In the proposed system, the control of stator flux linkage is avoided because every commutation will cause the stator flux linkage decreasing dramatically and sharp dip appears on the locus of the stator flux linkage every 60 electrical degrees. The best way to control the stator flux linkage amplitude is to know the exact shape of it, but it is considered too cumbersome in the constant torque region. Therefore the amplitude of stator flux linkage can be considered as a constant. The proper voltage vector selection is done using fuzzy logic controller which improves the dynamic performance. The sensorless operation is achieved by using a state observer. All the simulations were done in LabVIEW software of virtual instrumentation. Keywords—Brushless DC motor(BLDC), Direct torque control (DTC), fuzzy Logic controller, stator flux linkage, voltage vector selection, state observer, LabVIEW, virtual instrumentation.