Determination and realization of sensorless position detection method for a brushless DC motor

Applications using brushless DC/AC motors are becoming increasingly widespread today. These motors are controlled by special electronic circuits continue to acquire more specialized application areas with advances in semiconductor technology. Moreover, the utilization rates of these motors have increased with the availability of semiconductor element prices and specifications to the producers acceptable levels. The development of processors with larger memory structures and which ability to process more than one unit has opened up the possibility for motor control applications to be implemented with fewer elements. Sensorless motor control, reducing losses on the inverter layer, single or three shunts control and usages of PGAs on motor control topics attract the attention of manufacturers in the industry as well as academia. Academic studies and received patents can be shown as an examples of these. Also, energy efficiency and environmental awareness issues have gained importance and have entered into everyday life with legal regulations. Thus, brushless DC/AC motor control applications are frequently seen in industry, automotive, medical, household appliances, etc. areas. In this thesis study, researching, analyzing, designing, experimental and simulation studies are described for sensorless position detection of a BLAC/BLDC motor using a four switch inverter topology. Literature studies have focused on the detection of sensorless position of BLDC motor and the studies with four switch inverter topology. The structural blocks of the BLDC motor, their usages in the motor control, sensorless position detection methods and the theoretical background of the sensorless position detection of the four switch inverter topologies are explained. Important blocks in inverter hardware and software design are included. Sensorless position detection was achieved by a six-step (trapezoidal) method used in BLDC motor using a four-switch inverter topology with the designed electronic circuit. The position detection method has been verified using the motor in closed loop speed control. Experimental and simulation results are included. Keywords: BLDC, BLAC, motor, sensorless control, position detection, four switch, inverter, six step control, trapezoidal control