Research Of Active Power Filter On Small Ship Electric Propulsion System

Marine electrical propulsion system has ushered in a period of vigorous development withthe rapid development of power electronics technology and high power AC motor’svariable-frequency regulating speed technology continuing to mature. However, the harmonicproblem brought by a large number of power electronics technology applications in ships isbecoming the increasingly prominent and severe, serious ship accidents caused by harmonic hashappened at home and abroad. Especially for small electric propulsion ship, because the powergrid capacity is small, variable frequency driving power is relatively large, the generatedharmonics cause larger distortion of power grid voltage and current waveforms, which getsworse electric energy of ship power grid seriously and has great impact on capacity selection andsecurity of power grid. Therefore, the harmonic suppression research of small ship electricpropulsion system is becoming a very meaningful research subject.Active filter has high controllability and fast responsiveness, which can timelycompensation and does not increase the capacitance grid component, it is better than passivefilter’s filtering effect and has the incomparable superiority. As a key technique of the harmonicsuppression and improving the grid power quality, Active Power Filter can significantly improvepower system stability, which is widely recognized as one of the most effective means to solvethe problem of power system harmonics. In recent years, with the development of semiconductorindustry and the continuous improvement device cost performance, as well as the advance ofdigital signal processing technology, active filter gets more and more application in differentpower systems of domestic onshore power grid, but because ship power system hascharacteristics of strong coupling, small grid, large load, ship power grid voltage and frequencyparameter’s fluctuation is frequent, if onshore power constant grid frequency’s active filtertechnology is directly used to solve the ship power grid harmonic problems, the effect is oftenpoor and may lead to the whole ship accident of lost electricity, active filtering technology’srelated theory and the control method research which is suitable for small electric propulsionship power grid has not to achieve breakthrough results.Therefore, in this paper, using for reference from the basic idea of active power filter onshore, taking small ship electric propulsion system as the research object, the control strategy foractive filtering and parameter optimization methods is researched, simple and effectivecompensation method is discussed so as to solve the problem of ship electric power system harmonic interference, realize the stable operation of the ship electric propulsion system, meetthe requirements of ship’s clean power grid power quality. Specific arrangements are as follows:First of all, this paper introduces the concept of harmonic and ship electric propulsionsystem, then it discusses the influence of harmonic to the ship power grid and the reasons, andthen it expounds research status quo of ship power grid harmonic suppression at home andabroad, finally it illustrates the main work content of this paper.Secondly, it is focused on the working principle and topological structure of active powerfilter, and it is calculated the parameters of the device in detail in this paper.Furthermore, harmonic detection and compensation algorithm is further studied in thisarticle, the algorithm of measuring ship power grid frequency by adaptive notch filter is putforward, and good compensation effect is obtained through simulation.In the last place, according to the laboratory existing conditions, the experiment analysiswith TMS320F2812DSP chip as the core device is made, it is proved that the device can meetthe design requirements and verify the feasibility of design ideas through the experiment results.