Application of Fish Method to Inverter Switching Patterns Design and Torque Ripple Reduction for Induction Motors

• Main Authors: Chi-Hsiu Lin, 林琦修
• Other Authors: Jong-Lick Lin
• Format: Others
• Language: zh-TW
• Published: 2002
• Online Access: http://ndltd.ncl.edu.tw/handle/fg2j4p

碩士 === 國立成功大學 === 工程科學系碩博士班 === 90 === In general, a three-phase induction motor (IM) is driven by a switching power converter. Then the performances of IM, including torque ripple, power loss, peak current and acoustic noise etc. are related directly to the switching pattern. Therefore, how to optimize the rotating performances of an IM by adjusting the switching pattern becomes an important issues. In this thesis, a novel equivalent circuit of IM using the ideal rotating transformer (IRTF) is proposed. It is interesting to note that the novel equivalent circuit is identical to the traditional one after detailed analysis.. It is aimed to study the switching pattern of power converter by the fish method in this paper. On the basis of the analytic flux model (AMF), the switching pattern of the inverter is investigated. Then the flux fish, related to a unique switching pattern, can be obtained after a coordinate transformation of the stator flux. It is worthy to note that lower torque ripple of IM is concerned with a smaller, rectangular looking flux fish. Based on the fish method, the novel switching patterns, including the off-line synchronous switching pattern and the on-line asynchronous switching pattern, are designed to reduce the current ripple and torque ripple. Then the optimal performances of IM can be obtained. Among them, the off-line synchronous switching pattern is related to the open-loop control. On the other hand, the on-line asynchronous switching pattern, regarding of the varying DC-link voltage , is related to closed-loop control. The novel switching patterns and the traditional SPWM switching patterns are both simulated by Simulink. Some comparison results are shown for comparisons in the thesis. Moreover, it is desired to implement two types of the novel switching patterns to reduce the current ripple and torque ripple by a DSP microprocessor controller in the near future. In addition, the traditional SPWM switching patterns will also be implemented for comparison. Finally, the validation of the fish method will be successfully verified by simulation results.