Online Boundary Computation Using Sampled Voltage Reference for Bus Clamping PWM-Based Hysteresis-Controlled VSI-Fed IM Drive

Abstract

A current error space phasor based hysteresis current controller (HCC) with online computation of the current error boundaries using estimated sampled voltage references (SVR) for a two-level voltage source inverter (VSI) fed induction motor (IM) drive is proposed in this article. The space vector based current error of a two-level VSI-fed IM is monitored to keep the current error within the precalculated boundaries. The boundaries are computed knowing voltage error vector estimated from the current error information along α and β axes of IM. Vector selection logic is deduced to extract the features of voltage-controlled (VC) –30° and 60° bus clamping (BC) space vector pulsewidth modulation (SVPWM) based VSI-fed IM drive. The proposed HCC produces phase voltage harmonic spectrum and current error trajectories similar to that of a constant switching frequency—VC-BCSVPWM drive. It ensures adjacent voltage vector switching and retains all inherent advantages of a conventional HCC such as fast current control and has got a simpler controller implementation. A simulation model using MATLAB/Simulink is developed and analyzed over a wide speed range and experimentally validated using a dSPACE controller board on a 2.2 kW, 415 V, 3ϕ IM drive.