LOW COST AND PRECISE ELECTRONIC TACHOGENERATOR FOR SPEED CONTROL APPLICATIONS OF BLDC MOTOR DRIVE WITH 150-DEGREE CONDUCTION MODE INVERTER

Abstract

This experimental study presents a precise speedcontrol scheme for Brushless Direct Current (BLDC) Motor which is fedthree-phase inverter implemented 150-degree commutation mode.  In 150-degree commutation mode, four rotorposition signals are required. From these four position signals can be attainedpure analogue rotor speed information. Because there are four position signals,it can be easily obtained analogue rotor speed signal by implementing frequencyto voltage converter. So, low cost and further precise electronictachogenerator (ETg) can be put into practice in order to perform closed-loopprecision speed control for BLDC motors. In this study, 150-degree commutation technique hasbeen applied a BLDC motor and four rotor position signals have combinedproperly to attain higher frequency than one position sensor’s frequency toacquire pure analogue rotor speed information. After converting four positionssignals to pure analogue rotor speed information signal by frequency to voltageconverter circuitry for manufactured this study, it has been applied to a PIspeed regulator in order to obtain constant rotor speed versus changing load. BLDC motor driven 150-degree commutation has been rununder various loads and speeds and performance of the BLDC motor and ETg havebeen examined.Furthermore, a high resolution electro mechanictachogenerator is used in experimental setup in order to compare theperformances with proposed ETg.