Dspic33fj32mc204 Based Low Input Voltage AC Motor Driver Design and Implementation

Asynchronous machines are frequently preferred in industrial variable speed excitation systems due to their low cost, high durability, not need to maintenance requirements and not contain brushes and collectors. Despite these superior features of asynchronous machines, control is complex. Changing the number of poles, stator voltage or frequency methods are used for asynchronous machines speed control. Frequency changing ensures that the motor remains at the maximum torque value during speed control. For this reason, the voltage/frequency (V/f) ratio (or flux) is kept approximately constant. In this study, the speed of the asynchronous motor was controlled by changing the stator frequency. For this purpose, inverter and control circuits are designed. A 3-phase variable frequency voltage was obtained by using an inverter circuit designed with MOSFET semiconductor elements from the direct voltage. The power circuit is designed using 3 NPN type and 3 PNP type MOSFETs. The use of NPN and PNP type MOSFET transistors is intended to reduce the number of independent sources. The designed AC driver can be used for 12-24V input voltage range of three phase asynchronous motors. This study the AC driver is used for 90W asynchronous motor and drive at 12V and 24V variable input voltage values. The dspic33fj32mc204 microcontroller was used as a controller to achieve variable frequency and speed control.