FPGA Based Speed Control of Three-Phase Induction Motor Using Stator Voltage Regulator(dEPT.e)

In this paper a digital speed control strategy for three-phase induction motor is implemented. This strategy depends on varying the stator voltage to control the speed of the induction motor. The system consists of six bidirectional switches. The digital control strategy uses saw-tooth waveform with (wice the supply frequency as a control signal to be compared with triangular waveform as a carrier signal. The voltage output from a voltage regulator can be controlled by varying the voltage level of saw-tooth waveform The control strategy provides also soft starting for the induction motor, The soft starting is implemented by starting the motor in low value of modulation index and increasing it gradually during the starting period. The simulation of the system is carried out by a PSIM computer program. The control strategy is implemented by using FPGA. A detailed digital design of the control system has been introduced in detail. The simulation results have been compared with the experimental results from laboratory prototypes. The simulation and experimental results show stable operation for a wide range of speed control. The levels of harmonics in the supply and motor currents and power factor have been evaluated for different operating conditions.