Development and Experimental Testing of a 3o Resolution-Level Controlled WM Inverter-Fed Induction Motor

Abstract

This paper presents a novel speed control approach for inverter-fed three-phase (3φ) induction motors. The proposed approach is called the resolution-level controller (RLC) that is realized for the 3φ voltage-source (VS) wavelet-modulated (WM) inverters. The wavelet modulation technique generates switching pulses using a non-dyadic type multiresolution analysis (MRA) that is constructed by three scale-based linearly-combined scaling functions shifted by 2π 3 • from each other. Moreover, The change in the scale of the three synthesis scaling functions is based on the change of the sign of the first derivative of the reference-modulating signals. The three scaling functions have dual synthesis scaling functions that are responsible for reconstructing the three continuous-time reference-modulating signals from their nonuniform recurrent samples. The reconstruction processes are carried out by the three synthesis scaling functions to achieve 180-degrees conduction mode of the 3φ inverter. The proposed RLC approach is based on adjusting the zero-crossing locations of the first derivative of the reference-modulating signals to change scales of successive dilated and shifted versions of the three synthesis scaling functions. This change in scales can be incorporated to adjust the speed of the induction motor to meet load changes. The complete drive incorporating the RLC is successfully implemented in real-time using a digital signal processor board dSP ACE ds1102 DSP board to generate switching pulses to activate the inverter six IGBT switches. The IGBT inverter supplies a 1 hp, 1750 RPM, 208 V, 60 Hz, Y -connected 3φ squirrel-cage induction motor that is tested for several speed and load variations. The test results demonstrate robust performance, simple implementation, significant dynamic responses and high ability to maintain high quality outputs.

Analysis and Development of a Resolution-Level Vector-Controlled WM Inverter-Fed IPM Motor Drive

“…The details of developing the RLC strategy for WM inverters can be found in [13]. The objective of the RLC is to shift the three first derivative for adjusting the magnitude of WM inverter output voltages.…”

The Development and Testing of a Double-Loop Resolution-Level Controller for a 3ϕ WM Inverter-Fed Induction Motor

“…Moreover, the reconstruction part is carried out using inverter switching actions that can be viewed as sets of synthesis basis functions. In reference [5], the authors have defined a new scaling function for switching 1φ inverters. The defined scaling function is named scale-based linearlycombined scaling function ϕ(t), and is defined as [5]:…”

“…The steady-state operating of inverter-fed IMs is generally characterized by the presence of pulsating torque components due to the existence of different harmonic components in the inverter outputs [4,5]. Torque pulsation can cause effects in overstressing the rotor shaft and in producing mechanical resonances and speed oscillations.…”

“…This new type of inverters is called the wavelet modulated (WM) inverter [5]. This paper aims to develop and experimentally test a new intelligent control strategy for adjusting the output of a threephase wavelet-modulated inverter when supplying 3φ induction motor for several loading conditions.…”

“…This paper aims to develop and experimentally test a new intelligent control strategy for adjusting the output of a threephase wavelet-modulated inverter when supplying 3φ induction motor for several loading conditions. The proposed method is based on a double-loop resolutionlevel controller (RLC) [5]. The proposed double-loop RLC aims to change the scale (dilation) and to correct the translations of successive synthesis scaling functions of each phase.…”