Performance testing of a 2 Loop RLC WM inverter-fed induction motor drive

This paper presents the development and performance testing of a 2 loop resolution-level controlled (RLC) WM inverter-fed three-phase (3phi) squirrel-cage induction motor (IM) drive system. The proposed RLC WM inverter-fed IM drive is based on controlling the WM inverter output voltages using both a phase-shift thetas and the maximum value of the scale J. These two parameters are employed to adjust the locations and durations of the successive dilated and translated versions of the scale-based linearly-combined synthesis scaling function phi_j (t) that is responsible for activating the inverter switching elements. The proposed control approach is designed so that one loop is to hold J constant for small changes in thetas in response to steady-state deviations in the motor speed, while the second loop is responsible for adjusting thetas to vary the WM inverter output voltages. This control approach can offer stable and effective responses to both steady-state and step changes over a wide range of motor operating speeds. The 2 loop RLC WM inverter-fed IM drive is realized for both simulation as well as experimental performance testing under different operating conditions. Simulation and experimental performance test results show effective responses to different changes in operating conditions of the tested drive. Also, some performance comparisons are conducted with a fuzzy-logic and a proportional-integral controllers.