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Investigation and Suppression of Common-mode Resonance in High-power Transformerless Current-source Drives Systems
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- Author / Creator
- Lian, Yujuan
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Among high-power pulse-width modulation (PWM) current-source motor drives, the transformerless structure using the integrated dc choke to attenuate the common-mode (CM) voltage has been widely used due to the advantages of lower weight and costs without the isolation transformer. However, the CM inductor is still a heavy and costly component in such a system, and further scaling down the CM inductor without affecting the drive’s performance is always an important goal of the drive system design. As will be shown in this work, the size of the CM inductor is mainly related to the maximum CM current, which occurs under the resonant frequency of the CM circuit when motor speed is low. Also the potential CM resonance may be deteriorated with the implementation of power factor compensation (PFC) function in the drive. This thesis first conducts an in-depth study on the CM resonance, including the development of CM equivalent circuits, the influence of PFC on the CM resonance, and the relationship of CM choke size and CM current. Then active resonance suppression solutions are proposed in this work through modifying the PWM strategy of the high-power current-source converters. The working principles, CM voltage reduction performance, harmonic performance and switching frequency analysis of the proposed methods are presented. The investigation of CM resonance and the effectiveness of the proposed resonance suppression solution are verified by simulation and experiment.
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- Subjects / Keywords
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- Graduation date
- Spring 2016
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- Type of Item
- Thesis
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- Degree
- Master of Science
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- License
- This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.