Multipurpose digital controller (MDC) for motor drives

The presence of sequential processes in industry which requires motor drives of different characteristics introduce unnecessary cost, space and time if installed. In this research thesis, software controlled Multipurpose Digital Controller (MDC) was designed and implemented to control DC Motor, Single-Phase and Three-Phase Induction Motor drives sequentially. Vector control technique was used to verify MDC on Three-Phase Induction Motor, Single-Phase motor by constant Volt/Hertz principal and DC Motor control by varying armature voltage at constant excitation. Tools used for MDC implementation are MATLAB_Simulink, MATLAB-C2000 Toolbox, RTW and CCStudio V3.1 for Software; and Hardware employed were Intelligent Power Module (PM50RSK060) and F2812eZdsp. YOKOGAWA DL1540L Oscilloscope was used for measurements. MDC performance analysis was conducted in detail for a Three-Phase Induction Motor. Results show that, MDC concept has proven its control applicability. In case of Three-Phase Induction Motor and its control techniques, it was found to have flexibility in control to both, torque and speed because current and torque are decoupled in vector control. Parameter sensitivity towards the speed and flux behaviour of the Induction Motor was found to have great influence on the controller performance when the rotor time constant was made to deviate from its nominal value. Current controller and speed controller was implemented using PI controller in first order system to match the controlled Induction Motor.