Single-Phase Three-Wire Photovoltaic Inverter 鍾志祥 林育宗 蔡國隆 鄒應嶼 Smith Chung Yu-Tzung Lin Kuo-Lung Chai Ying-Yu Tzou
國立交通大學 電機與控制工程學系 電力電子與運動控制實驗室
Department of Electrical and Control Engineering, National Chiao Tung University, Power Electronics and Motion Control Lab.
摘要：本論文設計全數位控制之單相三線制太陽能光伏變
Abstract:This paper presents the design and implementation of a DSP-based fully digital-controlled single-phase three-wire photovoltaic inverter. This proposed Design consists of two parts:
the Boost converter extracts the largest free-natured energy from solar battery by adjusting the duty cycle of converter to the aim that can be achieve maximum power point tracking. The half-bridge inverter is used for output stage with multi-voltage and for parallel with a 1φ3W electric utility lines. It will be apply to the emergency power supply and generating electric power effectively. In order to achieve wide bandwidth, low harmonics and fast response system spec., the skills of dead-beat current control, voltage imbalance control are applied. The mentioned control algorithm, which is simple and fast, provides a significant improvement in system dynamic responses of imbalance or nonlinear load compared to conventional analog control techniques. The proposed control scheme has been verified by using computer simulation with PSIM and implemented using a single-chip DSP controller in future. Simulation results show the feasibility and superiority of the proposed DSP control scheme.
Ⅰ . 前 言 庭市電供電線制為單相三線制(1φ3W 110/220V)，光伏 變頻器 AC220V 輸出時無法提供中性點，除非裝設變壓 反相 AC110V 電壓，再以電壓差觀念，提供相對 AC220V 之較高輸出電壓，提供台灣地區家庭用戶所適用之市電 供電電源單相三線制(1φ3W 110/220V)，除提供兩種電 壓選擇之優點外，更可為將來太陽能系統與家庭用電線
中華民國第二十四屆電力工程研討會 台，如圖 2 所示，以 DSP 為基礎之數位控制板、功率級，
配合視窗化監控軟體 WinDSP，進行整合實測驗證。經 RS-232 作 為 數 位 控 制 卡 與 電 腦 間 資 料 的 連 結 ， 因 WinDSP 具有線上觀察控制波形與調整控制器參數的功 能，使控制程式之發展更加方便與快速。
S4 S2
S3 S1 Solar Cell Array
AC 110/220V (50/60Hz) High-frequency
Boost Converter Low-frequency
Inverter Bridge AC filter
Single–phase Three–wire Electric Utility Lines
G
B N A
Digital Signal Processor
DSP Optional Front Panel Controller
RS – 232 or 422 Grid Voltage Feedback
Inverter Current Feedback Grid Voltage
Feedback Ground
Current Feedback Solar Cell Array
AC 110/220V (50/60Hz) High-frequency
Boost Converter Low-frequency
Inverter Bridge AC filter
Single–phase Three–wire Electric Utility Lines
G
B N A
Digital Signal Processor
DSP Optional Front Panel Controller
RS – 232 or 422 Grid Voltage Feedback
Inverter Current Feedback Grid Voltage
Feedback Ground
Current Feedback 板之最大輸出功率點(maximum power point: MPP)，成為 前級功能設計重點；升壓式直流轉換器屬單開關直流轉
d Dead-beat Current
d Dead-beat Current
d Pulsewidth Modulator
d Pulsewidth Modulator AC110V，再以差壓方式得到 AC220V，此硬體設計及 控制，相較於三相六開關晶體控制，可簡化硬體之複雜 度及控制之穩定性，以下就以單一半橋式變流器討論 之。一般而言，其脈波寬度調變可分為單極性切換 (Unipolar PWM)與雙極性切換(Bipolar PWM)，產生之脈 寬調變電壓後，經過 LC 濾波電路得到基頻正弦信號。
中華民國第二十四屆電力工程研討會
d Dead-beat Current
d Dead-beat Current
d Pulsewidth Modulator Current Controller
vo
d Pulsewidth Modulator Current Controller
圖 5 變流器之 Dead-Beat 電流控制器 705μF，開關頻率為 24 kHz，輸入電感 2.5mH，輸出電 感 1mH，輸出電容 36μF，再以 DSP 為控制器實現軟體
IA(rms)＝10.6A IB(rms)＝10.6A IN(rms) ＝0A VAN＝110V VBN＝110V VAB＝220V
IA(rms)＝10.6A IB(rms)＝10.6A IN(rms) ＝0A IA(rms)＝10.6A IB(rms)＝10.6A IN(rms) ＝0A
中華民國第二十四屆電力工程研討會
VAN＝110V VBN＝110V VAB＝220V
IA(rms)＝5.3A IB(rms)＝15.9A IN(rms) ＝10.6A VAN＝110V VBN＝110V VAB＝220V VAN＝110V VBN＝110V VAB＝220V
IA(rms)＝5.3A IB(rms)＝15.9A IN(rms) ＝10.6A IA(rms)＝5.3A IB(rms)＝15.9A IN(rms) ＝10.6A
圖 8 不平衡負載輸出電壓模擬圖
IA(rms)＝9.6A IB(rms)＝9.5A IN(rms) ＝4.2A
VAN＝110V VBN＝110V VAB＝220V IA(rms)＝9.6A IB(rms)＝9.5A IN(rms) ＝4.2A IA(rms)＝9.6A IB(rms)＝9.5A IN(rms) ＝4.2A
VAN＝110V VBN＝110V VAB＝220V VAN＝110V VBN＝110V VAB＝220V
圖 9 電容電壓不平衡時輸出電壓模擬圖
Ⅴ . 結 論
本論文設計完成一個以單晶片 DSP 控制器為基礎 的全數位單相三線制太陽能光伏變流器，具有電路簡 單、效率高、符合市電併聯需求與快速動態響應的特 色，全數位式設計達到光伏能之高轉換效率、最大功率 追蹤及市電併聯技術及保護等多項複雜之快速控制需 求，採用多迴路控制方式，回授調整追蹤太陽能板之最 大輸出能量，提供穩定之直流鏈電壓；後級則控制兩組 半橋式轉換器輸出提供共地點，適合市電併聯需求以發 展併聯技術。未來配合 DSP 完成此架構，更可利用 DSP 之周邊擴充能力強，可完成網路遠端監控及能源管理之 目的，將能俾助於各種能源轉換上之應用。
參 考 文 獻
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