Study of Different Hybrid Converter Topologies for Brushless DC Motor Drive

Abstract

newline This thesis presents the performance analysis of different hybrid converter topologies for newlinebrushless DC motor (BLDC) drive. More elaborately it presents electromagnetic torque newlineripple minimization scheme by using these hybrid DC-DC converters for BLDC motor newlinedrive. newlineThe novelty of this work lies with the introduction of two new hybrid converters, viz. newlineHybrid Boost Single Ended Primary Inductor Converter (SEPIC) and Switched-Capacitor newlinebased SEPIC converter. Once the said hybrid converters have been developed and delivered newlinesatisfactory voltage gain, they are used to replace the conventional converters in converter newlinefed topology for BLDC motor drive. The performance analysis for the proposed BLDC newlinedrive is conducted based on the presence of ripple in electromagnetic torque. The affect of newlineintroduction of these hybrid DC-DC converters on torque ripple minimization is analyzed newlineand finally compared with other converters. Based on the study along with the results newlineobtained, this thesis is divided into five chapters. newlineChapter 1 introduces the work with a brief review on the popularly available DC-DC newlineconverters and provides the background information required for understanding the development newlineof new hybrid converters for BLDC motor drives in general. This chapter begins newlinewith the discussion about different causes of torque ripple in BLDC motor drive. In addition, newlineit also presents an elaborate discussion on various techniques available in literature newlinefor torque ripple minimization for the said drive. newlineAn elaborate numerical analysis on the ripple in electromagnetic torque of BLDC motor newlineis presented in Chapter 2. Moreover through numerical analysis, this section describes newlinethe effect of DC-DC converter fed BLDC motor drive on modulation of DC link voltage; newlinethereby developing a mathematical relationship between the output voltage of the DC-DC newlineconverter and the torque ripple. As a result, this relationship establishes a co-relation newlinebetween duty ratio of the converter with the torque ripple. newlineKeeping in view the discussion of chapter 2, now it is time to know more about different newlinetypes of hybrid DC-DC converter topology (viz. Two-inductor Boost Converter, Hybrid newlineBoost SEPIC Converter and Switched Capacitor based converters) that is given in Chapter newline3. In the detailed study of the said converters, the design considerations for these hybrid newlineconverters are also taken into account. The variation of output voltages for different duty newlineratios along with the capacitor voltage and inductor current have also been considered newlineiv newlinehere.The comparative analysis on the output voltage gain for the previously mentioned newlinehybrid converters has been studied both analytically and experimentally. newlineIn Chapter 4 the proposed BLDC drive with the hybrid converters (namely Two-inductor newlineBoost Converter, Hybrid Boost SEPIC Converter and Switched Capacitor based converters) newlinehas been described. This chapter also deals with the hardware implementation of the newlinesaid converters and their performances. Finally, an effort has been made to investigate newlinethe reduction of torque ripple in the proposed BLDC motor drives with these three hybrid newlineconverters. Besides, the change in commutation time and torque ripple are analyzed for newlinethe variation of duty ratio. newlineSubsequently, Chapter 5 summarizes the work by considering the percentage torque ripple newlinepresent in electromagnetic torque for all the drives presented in previous chapter. By newlinestudying all these three converters in BLDC drive, the best optimal choice of converter for newlinea particular application is also determined. Finally the future scope of the BLDC drives newlinehas also been discussed here.