Real-time observer for the vector control of an induction motor drive

Using vector control (VC) theory for AC machines can result in high performance speed and torque responses. An induction machine driven by a vector control system exhibits behavior similar to a separately excited DC machine with independently controlled flux and torque. In this paper the d-q model of an induction motor drive is used to derive the state space matrix representation of the drive system. A state observer model using the machine currents and speed measurements is analyzed. The estimator is derived by direct synthesis from the state equations. A space vector pulse width modulation (SV-PWM) inverter is used to supply the power waveforms to the induction motor. The model implementation and system simulation is performed using MATLAB/Simulink software. Finally, the overall vector control system is validated in real-time using a hardware in loop (HIL) system based on the dSPACE CLP1104 control board.