Field Oriented Control of Permanent Magnet Motor with Sliding Mode Observer

The paper discusses the sensorless Field Oriented Control (FOC) of BLDC motor with continuous rotor position information through a Sliding Mode Observer (SMO). Mathematical formulation and implementation of SMO with sigmoid switching function is presented. A sigmoid sliding surface is chosen for SMO to reduce the chattering problem. The FOC algorithm is developed with objective to maintain the stator current sinusoidal for both types of Permanent magnet (PM) motor i.e. PMSM and BLDC. The developed algorithm is tested in simulation for both PMSM and BLDC in MATLAB and is implemented for a 52W BLDC motor on Texas C2000 (F28027) microcontroller with Boost XL-DRV 8301 as the three phase gate driver from Texas. A graphical interface (GUI) is also developed using Texas MOTORWARE that shows the efficacy of the control algorithm with high speed tracking accuracies under almost all the operating conditions.