用於混和電源系統之前端數位脈寬調變直流轉換器研製

Abstract

本論文旨在研發微控器為基礎之直流至直流轉換器，用以提供混合式電源管理系統之前端直流電源，其鎖定輸入電流之特性可以有效避免燃料電池因電壓過低而造成損壞的可能性。數位化控制系統具有高穩定性、高抗雜訊能力與優良的可規劃特性，同時應用在直流對直流轉換器可以避免類比元件老化造成性能衰減的問題。本論文涵蓋之系統分成電源轉換器、數位控制補償器、與混合式電源管理系統等三大架構。首先，在電源轉換器的部分為前級的升壓直流對直流轉換器電路，為燃料電池端對鋰電池端之直流轉換器。其次，對於數位控制補償器採用Microchip公司的dspic微控制器(型號：33FJ06GS202)，利用該晶片強大控制與運算能力穩定實現type-III補償器；再者，利用dspic微控制器內建之高精度類比對數位轉換器擷取電壓物理量，進行閉迴路控制並產生高精度數位脈寬調變信號，使直流電源可以達到穩定輸出。最後，於混合式電源管理系統，以雙鋰電池為主、質子交換膜燃料電池(PEMFC)為輔供應負載能量。而鋰電池切換系統用以避免鋰電池長時間保持在高容量或者低容量的狀態，以延長該電池組壽命。

In this thesis, an implementation of microcontroller based front-end DC-DC converter for hybrid power management system is presented. This DC-DC makes Proton Exchange Membrane Fuel Cell (PEMFC) not to be damaged at low voltages by controlling the input current. Besides, a digital control system has high stability, high noise immunity and can be programmed for any situation. For a typical DC-DC converter, the aged passive components can be a problem that causes the performance to decrease. On the other hand, a digital DC-DC converter can avoid this problem. In this system, DC-DC converters with digital microcontroller and a power management are included. A boost converter implements power conversion for dual Li-ion battery packs and a proton exchange membrane fuel cell (PEMFC). The converter is controlled by a Microchip dspic33FJ06GS202 microcontroller with a digitalize type-III compensator. This device has high-speed 10-bit ADCs and high-speed PWM Modules in order to sense output voltage and generate PWM signals more precisely. A switching Li-ion battery circuit is also be monitored to avoid batteries in a high Depth of discharge (DoD) situation.