本文旨在研製以質子交換膜燃料電池為能源之燃料電池功率轉換系統。整體系統架構包含用於燃料電池之多臂式直流-直流功率轉換器、單相三線式交流電壓輸出之直流-交流功率轉換器，及可對蓄電池充放電之昇/降壓型直流截波器。系統之輸出除可供應交流負載外也可供應直流負載。此外，文中提出之燃料電池功率轉換系統已克服質子交換膜燃料電池之低壓大電流、響應時間長之特性，並且滿足燃料電池電流漣波之要求。
針對燃料電池低壓大電流輸出特性，本文採用多臂式直流-直流功率轉換器將燃料電池輸出電流均勻分配至各個開關，達成降低開關電流額定及均勻散熱之目的。本文提出用於多臂式直流-直流功率轉換器創新之交錯式脈波寬調變，利用一個時鐘即可產生多組脈波寬調變輸出，對於不支援相移控制之數位訊號處理器，可應用此方法輸出交錯式脈波寬調變。在均流控制上採用責任週期前饋控制，不僅可簡化均流控制也可降低數位訊號處理器之運算時間。
因應燃料電池響應時間長之缺點，系統採用響應較快之蓄電池為能量緩衝器並結合能量管理可彌補燃料電池化學能轉電能之反應時間，使系統不管瞬間加入直流負載或交流負載都可維持動態之能量平衡。能量管理除「暫態補償模式」可降低燃料電池對系統動態響應之影響，其「協同供電模式」在燃料電池能量不足時可由蓄電池分擔部分負載，此外蓄電池在「蓄電池充電模式」可由燃料電池補充能量。
本系統架構含直流-直流及直流-交流功率轉換器，若不經控制將會為燃料電池分別引進高頻開關頻率及二倍市電頻率之電流漣波，過大之電流漣波會導致燃料電池受損，因此系統採用多臂式直流-直流功率轉換器及設計輸入電感使各臂電感電流維持在連續導通模式，並搭配交錯式脈波寬調變及均流控制降低燃料電池開關頻率之電流漣波。對於二倍市電頻率之燃料電池電流漣波，本文以帶拒濾波器及直流鏈電容值之設計來抑制直流鏈電壓之二倍市電頻率之低頻電壓漣波，間接降低燃料電池電流之低頻電流漣波。
在數位調節器參數設計上，透過小信號模型以直接設計法(direct design method)結合頻率響應設計系統中各功率轉換器之調節器參數，可縮短調適參數時間也可幫助直流鏈電壓、電感電流及交流電壓等控制信號兼顧動態響應及穩定度。
本文提出之燃料電池功率轉換系統採用32位元之數位信號處理器(DSP，TMS320F2812)為整體系統之控制核心，除電力電路、回授電路及驅動電路外皆由數位信號處理器取代。本文已完成1 kW系統雛形，其輸入為燃料電池及24V蓄電池，輸出可供直流負載及交流負載，對直流負載效率為94.8%、對交流負載效率為89.2%，燃料電池電流漣波因數小於4%。

This dissertation presets the application of fuel cell power conversion systems based on proton exchange membrane fuel cells. The system introduces multi-leg dc-dc power converters, buck/boost converters, and single-phase three-wire dc-ac converters for fuel cells, batteries, and ac/dc outputs. The presented fuel cell power conversion system overcomes low-voltage-high-current behavior and slow dynamic response of fuel cells, and meets current ripple requirements.
For low-voltage-high-current behavior of fuel cells, multi-leg dc-dc converters is adopted to decrease current standing rating of switches, while interleaved switching techniques and current sharing control are introduced. This dissertation proposes a novel phase-interleaved pulse-width modulation for the converter, which can significantly minimize the number of timer to one regardless of the number of PWM outputs. On the other hand, the current sharing control with duty feedforward not only achieves equal current distribution, but also save computation time of digital signal processors.
As to fuel cell slow dynamic response, the system uses batteries to serve an energy buffer to dynamically and quickly sustain energy balance by battery discharging. In addition to discharging, the system charges batteries, when fuel cells are able to supply this extra load from charging.
The dc-dc and dc-ac converters of the proposed system bring current ripples at switching frequency and twice utility frequency for fuel cells. To meet the power conditioning requirements for fuel cells, multi-leg boost converter with phase interleaving pulse-width modulation is proposed for the system. The converter always operates in continuous conduction mode to conform to the current ripple specification with designed input inductors. However, this method which is only for high frequency current ripples can not depress the current ripples at twice utility frequency. A notch filter with designed dc-link capacitors are presented to reduce voltage ripples of dc-link capacitors, which can indirectly decrease low frequency current ripples.
The control parameters of regulators for fuel cell power converters are designed by frequency response and direct design method through small-signal models. This analytic method can save the time of parameters tuning, and compromise system dynamic response and stability. The relative control of the system is realized by a 32bit digital signal processor, TMS320F2812.
Finally, experimental results of a 1 kW prototype are given to justify the feasibility of the implemented fuel cell power converter system through a digital signal processor. The system inputs use fuel cell and 24V batteries, and can supply dc and ac loads. Besides, experimentally it shows an efficiency of 94.8% at dc loads and of 89.2% at ac loads, and current ripple factors under 4%.

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