研製具有輸出變壓器與用戶端電壓迴授之交流電源供應器

Design and Implementation of an AC Power Supply equipped Output Transformer with User-Side Voltage Feedback

黃夢谷(Meng-Gu Huang)

指導教授 ： 黃明熙

國立臺北科技大學/電資學院/電機工程系所/碩士(2009年)

摘要

本論文主要在研究數位功率控制於交流電源供應器之應用。此交流電源供應器採用全橋架構，具備輸出端隔離變壓器與用戶端之電壓迴授，以避免輸出電壓含有直流成分對於用戶端的設備造成損害。一般而言，直流-交流轉換器的輸出電壓中不可避免地含有直流成分，其會造成隔離變壓器飽和與電壓諧波成分變高。故在此提出了改善之電壓控制法則，可以有效降低直流成分對於隔離變壓器之影響。此控制法則主要包含了三個部分：電流直流成分消除器、電壓控制器與電壓均方根值補償器。電流直流成分消除器之功能為偵測隔離變壓器之一次側電流，經由低通濾波器以取出其直流成分，將此成分與零命令做PI控制，迫使直流成分降為零。電壓控制器與電壓均方根值補償器則可以強化輸出電壓之控制能力，如：電壓命令追蹤、負載變動調節、暫態恢復能力與高頻控制。
系統是以數位信號處理器(TI DSP TMS320F2809)作為控制核心來實現數位功率控制。經由實驗結果可以看到系統在寬廣的頻率範圍之下具有良好的命令追蹤與負載調節能力，驗證所提控制策略之有效性。

關鍵字

直流-交流轉換器 ； 隔離變壓器 ； 數位功率控制

並列摘要

The objective of this thesis is to design a digital control single phase AC power source, which equipped with output isolation transformer. The power source consists of a full-bridge DC-AC inverter and a transformer which is installed between inverter and user side to avoid feeding DC voltage into user’s equipments. Generally, it is difficult to design an AC inverter without DC voltage component in output. And the DC voltage will let the connected transformer be saturated, which may increase output voltage harmonics and power loss of transformer. An improved voltage control approach with transformer output voltage feedback is developed to reduce the effects of DC input current and voltage drop for transformer. In the improved method, a DC current canceller, a voltage controller, and a rms voltage compensator are proposed to enhance voltage performance of the AC power source. The DC current canceller detects DC current of transformer through a lower pass filter, and mitigates the DC current using PI controller with zero DC current command. As for the latter two control modules, they are utilized to further control the transformer output voltage such that voltage command tracking performances during loaded cases, transient period, and high frequency can be improved.
To facilitate the studies performed in this thesis, a DSP-based controller is constructed and all the control algorithms are performed by software. Some experimental results show that good command tracking and load regulation in wide output frequency range can be achieved by the proposed control method.

並列關鍵字

DC-AC inverter ； Isolation transformer ； Digital power control

參考文獻

[22] 鄭晨維，以數位訊號處理器實現多模組並聯之直流-交流轉換器，國立台北科技大學電機工程系碩士學位論文，民國96年一月。

[1] M. N. F. Nashed, “Low cost highly efficient of complete PV system,” in Proc IEEE PCC, vol. 2, pp. 845–849, 2002.

[2] D. Dah and Chan. Lu, “ Synthesis of Single Phase DC/AC Inverters,” in Proc IEEE ICIEA, pp. 1922–1926, 2007.

[3] W. Shireen and H.R. Nene, “DSP-based control for reliable fuel cell power systems with input ripple current compensation,” in Proc. IEEE PES, pp. 1–4, 2008.

[4] K.S. Low, “A digital control technique for a single-phase PWM inverter,” IEEE Trans. Ind. Electron., vol. 45, no. 4, pp. 672–674, Aug. 1998.