Sensorless Speed Control of FSTPI Fed Brushless DC Motor Drive Using Terminal Voltage Sensing Method
R. Manikandan1, R. Arulmozhiyal2, M. Sangeetha3
1R.Manikandan, Department of EEE, The Kavery Engineering college, Salem, India.
2Dr.R.Arulmozhiyal, Department of EEE, Sona College of Technology, Salem, India.
3M.Sangeetha, Department of EEE, The Kavery Engineering college, Salem, India.

Manuscript received on March 01, 2014. | Revised Manuscript received on March 04, 2014. | Manuscript published on March 05, 2014. | PP: 101-106 | Volume-4 Issue-1, March 2014. | Retrieval Number: A2071034114/2014©BEIESP
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Abstract: This paper presents the design to control the speed of permanent magnet brushless DC motor using sensorless method. In conventional operation Hall sensors are used to detect the position of the rotor windings and according to which the six switches of the voltage source inverter are gated. In sensorless method, zero crossing point of back EMF of line voltage differences are measured, which will give the information about the phase which is to be energized. The zero crossing instant of back EMF waveforms is estimated indirectly from the measurement of three terminal voltages of the motor, from which correct commutation instants of the six switches are estimated. A direct phase current control method is used to control the phase currents in four switches. Cost reduction is achieved by elimination of three Hall Effect position sensors and the numbers of power switches are reduced to four instead of six. An algorithm for four switch topology is developed with the third winding connected to the neutral of the supply line and performance of the developed sensorless technique is demonstrated by simulation. The hardware implementation is done by using PIC16F877 and the voltage and virtual hall signals are verified.
Keywords: Brushless DC motor, four switch inverter, sensorless control.