Analysis of Induction Motor Subjected to Nonsinusoidal Voltages Containing Subharmonics

Induction cage machine supplied with voltage containing subharmonics and interharmonics

“…The research on an induction motor supplied with voltage containing an undesirable subharmonics injection was initiated by Lazim and Shepherd in 1985 [29]. The effect of SaI on currents, efficiency, instantaneous power, rotational torque, flux and thermal loads of an induction machine was studied in [8,[21][22][23][24][25][27][28][29][30][31][32][33][34][35][36]. The most thorough investigations of SaI currents are presented in the works of Tennakoon et al [ 8,34].…”

Harmonics Phase Shifter for a Three-Phase System with Voltage Control by Integral-Cycle Triggering Mode of Thyristors

“…The resulting threeload voltage waveforms are identical and so are the three-load current waveforms. The supply frequency components are found to be balanced, since they are 120 o apart in time-phase while the phase displacement angles of a particular subharmonic or higher order harmonic are unbalanced [11,12] . Due to the unbalanced phase relationships of the subharmonic components, these components represent a source of trouble when these voltage waveforms are used to feed ac machines for speed control purposes [11] .…”

“…The supply frequency components are found to be balanced, since they are 120 o apart in time-phase while the phase displacement angles of a particular subharmonic or higher order harmonic are unbalanced [11,12] . Due to the unbalanced phase relationships of the subharmonic components, these components represent a source of trouble when these voltage waveforms are used to feed ac machines for speed control purposes [11] . In this research an attempt is made to study the phase unbalanced characteristics of the subharmonics as well as the higher order harmonics generated due to integral-cycle triggering and to find a new phase shifting technique that is capable of correcting the unbalanced phases based on microprocessor implementation [14] .…”

“…As a frequency changing scheme, integral-cycle triggering was found not feasible for applications in the three-phase systems exploiting this technique for ac motor speed control [11] . This is because the amplitudes and phase displacement angles of the higher order harmonic and subharmonic components of the integralcycle controlled waveform are determined by the conduction period N and the control period T and the order of the individual harmonic.…”