Indirect Field Oriented Control for Three-Phase Induction Motor Drive Using DSP Controller

For efficient speed control of three phase induction motor mostly vector control (VC) or field-oriented control (FOC) technique is applied to the Voltage Source Inverter based-Induction Motor Drives (VSI-IM). In implementing FOC, the angular position of the rotor flux vector (θ) is to be evaluated. The accurate estimation of this vector θ along with the feedback parameters is the most critical aspects as the entire FOC logic is based on it. In this paper, an attempt has been made to implement the Indirect Field Oriented Control (IFOC) scheme by estimating θ from slip frequency and rotor frequency through a DSPIC30f4011 microcontroller using its capture module. The hysteresis modulation technique is used for generating the gate pulses of power circuit of VSI. The power MOSFETs are triggered using high-speed gate driver with bootstrap and motor protection circuits embedded in it. The IFOC scheme is then verified with 3KW IM using a prototype VSI model. It has been seen that this VSI-IM with IFOC scheme gave a satisfactory result with varied torque and speed.