CHATTERING REDUCTION AND OPTIMIZATION OF POWER CONVERTERS
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The Ohio State University / OhioLINK
2011
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ndltd-OhioLink-oai-etd.ohiolink.edu-osu13068714902021-08-03T06:02:58Z CHATTERING REDUCTION AND OPTIMIZATION OF POWER CONVERTERS Al-Hosani, Khalifa Hasan Electrical Engineering sliding mode multidimensional sliding mode observer estimation power converters power electronics renewable energy Sliding Mode Control (SMC) has become one of the most attractive control techniques due to its robustness and low sensitivity to disturbances and parameters variations. Due to the binary nature inherited in modern power converters mainly controlled by switches with ON and OFF as the only possible modes of operation, SMC is the logical choice when dealing with such systems. An obstacle in implementing SMC in many such systems is the presence of finite amplitude and frequency oscillation called chattering, or better known as “ripple” to the power electronics community, which are mainly caused by imperfections in switching devices. The level of chattering is found to be proportional to the switching frequency. Recent advancement in the semiconductor industry has lead to production of switching devices that can handle powers of dozen KW at frequencies of hundreds KHz. However, switching comes at a very high price as heat and power dissipation increases with increasing switching frequency. The most promising way to find the trade off between the desired level of frequency and level of heat loss is so-called “harmonic cancellation” principle, which implies replacing one converter by a multi-phase one, consisting of a set of parallel converters with the same admissible ripple frequency. Phase shifts between channels or converters are controlled such that the level of the ripple is reduced considerably after summation of the outputs of the phases.The main objective of this thesis is to provide theoretical treatment of chattering reduction through the use of specially interconnected multiphase power converters. The theory is applied to reduce chattering in the case of sliding mode controlled DC/DC boost and buck converters. This thesis also deals with system’s identification and parameters’ estimation. In many of the estimation techniques found in the literature, convergence of the estimates is usually proven but the convergence rate can be too low. However, in control system, the convergence rate is of great importance to the operation of the controller because of the dependency of system dynamics on these unknown parameters. A novel technique is introduced in this thesis where a linear operator is utilized in the sliding mode estimation scheme to provide some control of the convergence rate of the estimation process. The high level of heat losses for high power DC/AC converters is a crucial problem. In contrast to DC/DC converters with inverse proportional dependence between frequency and ripple amplitude, there exists one additional degree of freedom in DC/AC converters: indeed, the DC/AC converter for three-phase load is designed for controlling two variables (for example, speed and flux of the AC motor). This additional degree of freedom can be utilized to minimize the frequency preserving accuracy (or ripple amplitude) at the same level. In this thesis, a methodology within the framework of multidimensional sliding modes is developed to utilize the above possibility to the full extent. 2011-07-28 English text The Ohio State University / OhioLINK http://rave.ohiolink.edu/etdc/view?acc_num=osu1306871490 http://rave.ohiolink.edu/etdc/view?acc_num=osu1306871490 unrestricted This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws. |
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NDLTD |
| language |
English |
| sources |
NDLTD |
| topic |
Electrical Engineering sliding mode multidimensional sliding mode observer estimation power converters power electronics renewable energy |
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Electrical Engineering sliding mode multidimensional sliding mode observer estimation power converters power electronics renewable energy Al-Hosani, Khalifa Hasan CHATTERING REDUCTION AND OPTIMIZATION OF POWER CONVERTERS |
| author |
Al-Hosani, Khalifa Hasan |
| author_facet |
Al-Hosani, Khalifa Hasan |
| author_sort |
Al-Hosani, Khalifa Hasan |
| title |
CHATTERING REDUCTION AND OPTIMIZATION OF POWER CONVERTERS |
| title_short |
CHATTERING REDUCTION AND OPTIMIZATION OF POWER CONVERTERS |
| title_full |
CHATTERING REDUCTION AND OPTIMIZATION OF POWER CONVERTERS |
| title_fullStr |
CHATTERING REDUCTION AND OPTIMIZATION OF POWER CONVERTERS |
| title_full_unstemmed |
CHATTERING REDUCTION AND OPTIMIZATION OF POWER CONVERTERS |
| title_sort |
chattering reduction and optimization of power converters |
| publisher |
The Ohio State University / OhioLINK |
| publishDate |
2011 |
| url |
http://rave.ohiolink.edu/etdc/view?acc_num=osu1306871490 |
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AT alhosanikhalifahasan chatteringreductionandoptimizationofpowerconverters |
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