以雙重解偶框重複控制法改善微電網孤島模式之負載諧波設計與實作

Design and Implementations of Improving Load Harmonics in Islanding Operations of Micro-Grids by Using Repetitive Control under the Double Decoupled Reference Frame

陳冠宇(Kuan-Yu Chen)

指導教授 ： 朱家齊

國立清華大學/電機資訊學院/電機工程學系/碩士(2013年)

https://doi.org/10.6843/NTHU.2013.00785

摘要

在電子電力裝置中，以定電壓定頻率(CVCF) 空間向量脈衝寬度調變(SVPWM)的電壓源轉換器(VSC) 為主要核心的不斷電系統(UPS)系統在蓄電池後備供電系統和微電網系統中得到了廣泛的應用，其輸出電壓波型的主要要求包括:穩態時的總諧波畸變率低(THD)，以及可以抑制不平衡負載所造成的電壓不平衡效果還有在換載時能有快速的暫態響應，而在本文中的控制器這三項輸出電壓要求都可以達到良好的效果。
在本文中研究了電壓源轉換器(VSC)的雙迴圈控制，首先以重複控制來實現外迴圈電壓控制用來減少由非線性負載所造成的電壓低階諧波並將FIR數位濾波器引入到設計中，之後再利用雙重解偶同步參考框(DDSRF)來當作內迴圈電流控制的方法，可以有效的控制PCC點上的電壓正負序成分來改善電壓不平衡的情況，並且消除因為控制正負序所造成的二倍頻擾動效應，除此之外還研究了重複控制的原理，穩定性，誤差收斂性，並對於重複控制器中Q(z)的幾種設計方法進行了簡單的介紹，比較了各種設計方法的優缺點。
此控制策略已經用PSCAD模擬程式驗證，並且用實際1KVA功率提供三相線對線220V交流電壓但在換載條件下時系統為2KVA功率，基頻為60Hz實驗室規格的VSC在負載為線性負載，不平衡負載，非線性負載三種不同情況下進行了實驗驗證效果皆與模擬結果相差不遠。

關鍵字

電壓源轉換器 ； 總諧波畸變率 ； 重複控制 ； 雙重解偶同步參考框

並列摘要

In the power electronic equipment, the uninterruptible power supply (UPS) systems are widely used whose core is a CVCF SVPWM voltage source converter. The technical characters of the output voltage waveform consist of low total harmonic distortion (THD) at steady state, and mitigate the unbalanced voltage caused by unbalanced load and the rapid transient response.
In this thesis, the dual-loop control of the VSC is studied. Not only using the repetitive control to imply the outer loop voltage controller to reduce the low harmonic of the voltage, but also using the double decoupled synchronous frame (DDSRF) to be the inner loop current controller to efficiently control the positive- and negative-sequence component of the voltage at the PCC to improve the voltage unbalanced situation, beside the repetitive control principle, stability and the eroor convergence rate are also studied.
The proposed control strategy has been validated through PSCAD simulations, and implemented as a laboratory-scale VSC system providing a 1KVA power to a three-phase 220V AC voltage with a fundamental frequency of 60 Hz.

並列關鍵字

Voltage source converter (VSC) ； Total harmonic distortion (THD) ； Repetitive control ； Double decoupled synchronous reference frame (DDSRF)

參考文獻

[1] J. A. P. Lopes, C. L. Moreira, and A. G. Madureira, “Defining control strategies for analysing microgrids islanded operation,” in Proc. IEEE St. Petersburg Power Tech, St. Petersburg, Russia, 2005.

[2] R. Lasseter and P. Piagi, “Providing premium power through distributed resources,” in Proc. 33rd Hawaii Int. Conf. System Science, vol. 4, Jan. 2000.

[3] Kalyan P.Gokhale, Atsuo Kawamura, Richard Hoft. “Deadbeat Microprocessor Control of PWM Inverter for Sinusoidal Output Waveform Synthesis,” PESC'85,pp.28-36, 1985.

[4] Naser M. Abdel-Rahim,John E. Quaicoe. “Analysis and Design of a Multiple Feedback Loop Control Strategy for Single-Phase Voltage-Source UPS Inverters,” IEEE Trans. Power Appli., vol.11, no.4, pp.532-541, July 1996.

[5] Shih-Liang Jung, Lien-Hsun Ho, Hsing-Chung Yeh, Ying-Yu Tzou. “DSP-Based Digital Control of a PWM Inverter for Sine Wave Tracking by Optimal State Feedback Technique,” IEEE-PESC’94 Conf. Rec., pp.546-551, 1994.