Fuzzy Control Of APF In The Electric Propulsion Ship Power System

Along with the rapid development of power electrics and power drives technology, modern motor control technology, control theory and computer control technology, the ships electric propulsion's application manifested certain superiority in the technology. Specially the POD propulsion device's development and its application explosively pushes up the market share of electric propulsion, demonstrates its huge development potential. Because advances electrical machinery's control to the ships is realized through the switching of electric power electronic device, massive harmonics is produced then. The harmonics will not only harass electrical network's normal operation, but also initiate kinds of breakdown and serious accidents. Therefore, harmonic suppression is an important guarantee for ship to run safely. The passive power filter (PPF) can only filter out certain order harmonics. This shortcoming is conquered by Active Power Filter (APF).By real-time monitoring through the network, The APF injected current into the system to offset the system harmonic currents. As APF takes so many advantages like robust, not easily occur with the network impedance resonance and good dynamic performance, the research on it applied to electric propulsion in the ship power system is of practical significance.In order to accurately analyze power system harmonic components contained and to study its inhibition programs, this paper firstly carry out the mathematical modeling of ship electric propulsion system components, including synchronous generator, excitation system, propulsion motors and propeller. A complete marine electric propulsion system simulation model is built with MATALB/SIMULINK then. The paper then analyze the APF structure, which can be divided into three sub-sectors including harmonic detection, compensation current control and DC voltage control, each of their theory and application of control programs with comparing, build on traditional PI regulator control of APF applying in the ship electric propulsion system modeling.To enhance the dynamic ability of APF in marine electric propulsion system, this paper applies on APF the fuzzy control theory. Two conventional PI controllers, respectively for compensation current control and DC link voltage control are instead by two fuzzy controllers to establish a fuzzy control APF applying in the ship electric propulsion system modeling.In MATALB/SIMULINK environment, build a ship electric propulsion system simulation models, respectively, add conventional APF and fuzzy APF. Simulation results show that the proposed fuzzy control strategy based on APF harmonic filter has better performance, the current THD is reduced to 2.52% that is consistent with IEEE-519 and China Classification Society of the total harmonic distortion ship standard. Otherwise its DC voltage is much stable.As the initial work of research on "based on DSP fuzzy control APF and its application in electrically propelled ship electrical network", this article realizes a design of single-phase current harmonics' detecting based on the TMS320F2812. The simulation and the actual result have confirmed the improvement algorithm of harmonic current examination.