INVESTIGATIONS ON CURRENT SPACE VECTOR BEHAVIOR IN HYBRID PWM CONTROLLED DUAL TWO-LEVEL INVERTER FEEDING A 3-� OPEN-ENDWINDING INDUCTIONMOTOR DRIVE

KONDAPALLI, RAMACHANDRA SEKHAR and Srinivas, Srirama (2013) INVESTIGATIONS ON CURRENT SPACE VECTOR BEHAVIOR IN HYBRID PWM CONTROLLED DUAL TWO-LEVEL INVERTER FEEDING A 3-� OPEN-ENDWINDING INDUCTIONMOTOR DRIVE. PhD thesis, Indian Institute of Technology Hyderabad.

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Abstract

Multilevel inverters are gaining more popularity in recent days because of their advantages like low harmonic distortion, reduced switching losses and increased efficiency etc. It has been demonstrated that the dual two level inverter fed open end winding inductionmotor drive ismanifestation of three-level inverter. In this thesis, performance of the dual two level inverter with hybrid PWMs are studied along with the studies on the open end winding induction motor drive performance characteristics. In this work, all the PWM techniques are implemented that are based on the concept of effective time placement in a sampling time interval. The effective time placement concept neither require look up tables nor require sector identification, it only require the instantaneous phase voltages for the implementation of PWM. The major contribution of this work is the investigations on current ripple in the dual two-level inverter feeding an open-end winding induction motor drive and it is demonstrated that the current trajectory can be theoretically obtained (in the stationary reference frame) directly from the switching state information of the dual two-level inverter. Two inverter switching PWMs and single inverter switching PWMs are used to analyze the current ripple in dual inverter configuration. Based on the analysis, in two inverter switching PWMs, discontinuous PWMs when employed for the individually inverters not only offer the advantage of reducing the total switching commutations in the inverters but also reduces the ripple content in the induction motor load. In single inverter switching PWM, SVPWM exhibit less current ripple compared to all other PWM variants. For both the above cases, analytical expression for the RMS ripple current and variation in RMS ripple current in one cycle of operation for different iii PWMs are also presented for the entire speed range of the dual-inverter drive. This thesis also presents novel PWM techniques for complete elimination of zero sequence voltage in dual two level inverter configuration using both inverter switch PWM and also single inverter switching PWMs thereby enabling the dual-inverter drive to be operated with the single DC power source instead of two isolated DC power sources. The torque ripple analysis of the open end winding induction motor is carried out with the zero sequence elimination PWM techniques and it is shown that the center placed effective time placement in ZSV elimination PWM exhibits less torque ripple compared to all other ZSV eliminated PWM techniques.

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IITH Creators:

IITH Creators	ORCiD

Item Type:

Thesis (PhD)

Uncontrolled Keywords:

Dual two level inverter; Open end winding induction motor dive; Effective time; 3-level inverter; Hybrid PWMs; Current ripple; Current trajectory; Torque ripple; Common mode voltage; Zero sequence voltage;

Subjects:

Electrical Engineering

Divisions:

Department of Electrical Engineering

Depositing User:

Team Library

Date Deposited:

29 Aug 2019 11:59

Last Modified:

30 Aug 2019 04:31

URI:

http://raiithold.iith.ac.in/id/eprint/6081