以被動式濾波器提高遊艇供電效率與品質之設計與驗證

Design and Verification of Passive Filters for Enhancing Service Power Efficiency and Quality in Yachts

變頻馬達驅動器於遊艇各式泵浦之節能及控制性能提升應用已日漸普遍。由於這類設備具有非線性電氣特性，使用時所產生的諧波（harmonics）已成為遊艇供電系統主要的干擾來源。被動式濾波器（passive filter）是一種針對特定頻率採用單調諧振之濾波裝置，由於技術成熟、操作可靠、安裝及維修成本較低，目前已被工業界廣泛使用來改善電力系統諧波。以往船上被動式濾波器的設計已有不錯的成效，然而系統中的虛功率會因被動式濾波器的使用產生改變，在這種情況下，系統中無效電流增加容易造成超前功因或甚至造成過電壓，危害系統運轉安全。為得到較好的諧波改善效果，本文針對遊艇電力系統特性，提出一套較有效的設計方法。被動式濾波器的主要元件被加以設計以滿足系統最小諧波失真電流及虛功率要求，期望在改善諧波的同時，亦增加船上發電機運轉效率，進而達到船上發電機節能效果。一艘具有多種諧波源設備之遊艇電力系統被用來說明本文提出的方法之設計方式。數值模擬及實際測試結果已證實本文提出的方法有不錯的執行效能。 Variable frequency drive (VFD) driven motors for various types of pumps on yachts are rapidly growing in number for energy-saving and control performance enhancement. Due to their nonlinear nature, they are the major sources of harmonics in yacht electrical power systems. The passive harmonic filters that adapt a single unit trap tuned at a specific harmonic frequency to serve as one of harmonic mitigation solutions because they offer mature technology, reliable operation, and lower installation and maintenance cost. A traditional passive harmonic filter design for VFD on board is generally acceptable, but when the reactive power changes due to passive filter in service, the system is exposed to rich reactive currents and could experience leading power factor or even the system overvoltage. To obtain better harmonic mitigation results, an effective methodology for designing single-tuned passive harmonic filters in yachts is proposed in this paper. The filter components are designed to meet minimum requirements in terms of harmonic current distortions and reactive powers while, at the same time, increasing on-board power generator efficiency and consequently reducing fuel oil required. A practical yacht power system with a great number of VFD is analyzed to illustrate the filter design. The numerical simulation and field testing results confirm the performance of the proposed method.