Research On Control Methods Of Harmonic In Power System Of Electric Propulsion Ship

With the great development of power electronic technology and high-power AC motor variable frequency drive technology, ship electric propulsion comes into a new flourishing period of development. Ship electric propulsion has many advantages over traditional propulsion, and is a hotspot of research in ship building now. According to current situation, ship electric propulsion will be the main trend of development of ship building in the future. Hence, it has vital operation significance to deeply research on ship electric propulsion.The massive employment of power electronics on ship has improved production efficiency and got better working conditions, however, on the other hand it converts some fundamental wave energy into lots of harmonics which are injected into power grid. The harmonics lead to larger equipment volume and more transmission loss, and deteriorate quality of power supply, and then affect the safety and economical running of power supply equipment and power consumers. The high volume of hamonics in power system on ship is sharply in contradiction with the stringent harmonic standards. Hence, harmonic problem has become the most important problem affecting quality of power supply. Now it is the urgent task to manage and control harmonics within permitting limits. This dissertation summarizes and analyzes existing methods dealing with harmonic problems, then does experiment research on passive and active power filters. And the outcomes of experiments comply with standards very well, and validate that the established models are reasonable and effectual. The research work can be concluded as follows:(1) This dissertation discusses the harmonic phenomena, and its sources, effects, limiting standards and control methods of power system on electric propulsion ship.(2) With analyzed existing harmonic control methods, the thesis specially discusses passive and active power filters, and then compares their advantages and disadvantages.(3) In allusion to the characteristics of passive filter, the dissertation summarizes its design procedure and method, and then carries out simulation experiment, the results of which conform to standards, and show the validity of simulation model.(4) In light of dynamic compensation characteristics of active power filter, and adopting current hysteresis control method, the dissertation establishes simulation model of shunt active power filter in SIMULINK software and then does some experiment. The outcomes indicate that shunt active power filter can elimitate harmonic current and reactive current efficiently, and possess of good dynamic characteristics.(5) Hybrid active power filter takes full advantages of passive and active power filters, and has high research value. This thesis founds the models of parallel and series resonant injecting HAPF and then carries out some experimentation. And the analyses of experiment results are consistent with standards well.