本研究之主要目的係針對小功率燃料電池混成動力系統做一評估,並進行 控制策略、驅動模式之設計和運轉測試。本文分三階段進行,首先選定系統規 格與系統架構,第二階段則分別對馬達控制器、電瓶與能量管理系統與主控制 器等做設計與製作,再整合成系統測試平台,進行性能測試;測試時,分別以 電動、燃料電池及混成動力的方式驅動馬達,得出最佳的控制策略。 實驗系統選定的燃料電池為 8V/150W,馬達為 6V/30W,電瓶為 6V/4A-h。 本研究設計的主控制器是藉由個人電腦,搭配 LabVIEW 控制軟體與 PCI 介面 之資料擷取卡等組成;共分為資料擷取與監控單元、馬達控制單元、運轉模式 選擇與能源管理單元等。資料擷取與監控單元主要是針對燃料電池及電瓶輸出 電壓、電流進行監控、擷取與儲存,並提供異常資訊之警示與處理。馬達控制 單元則是利用 LabVIEW 軟體及 NI PCI 6014 資料擷取卡,由 PIC16F877 單晶 片產生 PWM 脈波訊號,控制馬達轉速。並藉由轉速計的電壓輸出信號進行回 饋控制。運轉模式選擇與能源管理單元主要是針對電動模式、燃料電池模式與 混成動力模式等三種運轉模式進行控制,並對燃料電池或電瓶電源進行能源管 理。 實驗結果顯示,在以純電瓶電源的電動模式,馬達全速運轉 (7000 rpm) 時, 約於 100 分鐘內耗去 2.5A-h 電能;低速運轉 (2000 rpm) 時,約於 500 分鐘內耗 去 3.6A-h電能,使用歐盟 ECE-15 行車型態測試,則大約 270 分鐘耗去 2.7A-h 電能。至於純燃料電池模式運轉測試結果顯示,馬達全速運轉 (7000 pm) 720 分鍾消耗 10.0g氫氣;低速運轉 (2000 rpm) 消耗 4.4g 氫氣;使用 ECE-15 行車 型態,則消耗 5.0g 氫氣。 當電瓶起始殘電量為 100% 時,加入控制策略進行測試,結果顯示混成動 力模式的系統效率比未加入控制策略時提高了10% 左右,表示本實驗初步研擬 之控制策略,可以符合混成動力模式的運作需求。另外,在實驗中發現,在相 同的的電瓶起始殘電量下,因能量多做一次轉換,所以燃料電池回充至電瓶的 能量愈大,系統效率愈低。 本研究發現燃料電池相關性能,受到燃料電池質子交換膜含水量、溫度等 因素之影響,造成實驗的數據有些許誤差;另外,燃料電池在負載突增或系統 啟動時,電能輸出會有稍落後現象,此有待往後實驗者更深入探討,並尋找解 決方法。
The present study was aimed at evaluating the small hydrogen fuel cell hybrid power systems. And then we studied the controlling strategies, drive forces and operating tests. Pursuant to this objective, a fuel cell hybrid test bench was built to simulate hybrid vehicle running conditions. The facility was equipped with a computer controlled controller, dc motor and 8V/150W fuel cell hybrid system. This test bench can run in three different modes(electric power mode, fuel cell power mode and hybrid power mode. The electric power mode tested under several constant speeds and ECE-15 mode test. We found that it used battery power 2.5A-hr in 100 min under 7000 rpm, 2.7A-hr in 270 min under ECE-15 test. When tested in fuel cell mode, we found that 10.0g hydrogen could supply dc motor running 720 min under 7000 rpm and 720 min under ECE- 15 test used 5.0g hydrogen. When the system run in hybrid mode, we found the fuel stack power could be increased continuously in the range of high load (more than 6000 rpm) with assist of battery power. At very low load (less than 5000 rpm) the hybrid system can save extra energy to the battery that will used to assist fuel cell when high load is needed. The recharged energy was related with battery residual energy, hydrogen flow rates and dc motor load. This experiment found out a short time delay between the start of abrupt load increase and the response of the fuel cell or battery power. Whatever cause of the time delay in the system must be examined and solved in the later.