SPWM Volt/Hz Based Speed Control of Induction Motor

Induction motor is very popular in industrial applications due to simple construction, low cost, and cheap maintenance costs. Speed control of induction motor requires frequency and magnitude voltage control. Some Volt/Hz control strategies are applied in speed control of induction motor with various methods such as direct torque control, vector control, harmonic elimination. These methods are very popular but require complex calculations. This paper discusses a simple method to operate an induction motor using the SPWM Volt/Hz, by using a lookup table method. This method contains important numbers as a reference for sinusoidal reference signal used to produce SPWM signal by comparing reference signals and triangular wave carrier signals from dsPIC microprocessor. SPWM Volt/Hz is used because the manufacturing process does not require complex calculations, easy to operate and reliable for induction motor speed operations. To prove that SPWM Volt/Hz can apply on speed control of induction motor, analysis simulation and experimental works were done. They show the proposed control strategy is capable to operate induction motor at the proper speed.