本文旨在研製用於線性負載之單相全橋式換流器並聯控制系統。在並聯系統中，有一部為電壓控制模式的主控制模組，其餘各部為電流控制模式的從控制模組。在單相並聯的系統中，不僅可以維持輸出電壓及頻率，亦可將輸出電流分散至各單元模組。整體架構包含四組推挽式轉換器及單相換流器，並以控制器區域網路作為各單元模組間的通信，完成多組單相換流器並聯控制之同步及單元模組的模式切換，提高系統的容量及可靠度。
本文採用32位元數位訊號處理器TMS320F28069為系統之控制核心，且回授電壓及電流，以軟體完成閉迴路控制，故可減少電路元件，提高系統可靠度。本文已完成四組單相換流器模組之並聯與實測。在輸出端12Ω之等效負載下，實測結果顯示總輸出功率為968W，其中一組操作於電壓控制模式，輸出電壓為110V，總諧波失真率為2.5%；在正常操作下，總輸出電流8.8A及功率968W，由4組單相換流器平均分擔，電流閉迴路控制模式各組之總諧波失真率為4.6%，換流器並聯系統的效率為86.7%。在4組單相換流器正常運作，以及各種不同故障與主從模式切換操作情境下，計算機摸擬與實測結果相近，印證了本文控制策略之可行性。

This thesis aims to develop the parallel operation system of single-phase full-bridge inverters for linear loads. The proposed system consists of a voltage closed-loop controlled module and three current closed-loop controlled modules. It can not only sustain the output voltage and frequency, but also share output current and power equally. The circuit structure presented comprises four push-pull converters and their follow-up inverters. In addition, controller area networks are introduced for communication among units to synchronize the operation and mode switching of the inverters, expanding the capability and reliability of the system.
In this thesis, the 32 bit digital signal processor, “TMS320F28069”, is used as the control core to realize the closed-loop control with voltage and current feedbacks. This will thus reduce the circuit component and enhance system reliability. Experimental results indicate that the output voltage of the master inverter is 110V with the total voltage harmonic distortion of 2.5%. The overall output current of 8.8A and output power of 968W are equally distributed among the four single-phase inverters. The total current harmonic distortion of the three current closed-loop controlled inverters is 4.6% for each module. The efficiency of parallel operation system of inverters is 86.7%. In addition, simulation and experiments are given for various scenarios among the four inverter modules including normal and faulty operating situations. The close agreement between simulated and experimental results thus verified the feasibility of the control strategy proposed.

[1] Manoj D. Patil; Rohit G. Ramteke, “L-C filter design implementation and comparative study with various PWM techniques for DCMLI”, 2015 International Conference on Energy Systems and Applications, pp. 347-352, 2005.
[2] G. Spiazzi; E. da Silver Martins; J. A. Pomilio, “A simple line-frequency commutation cell improving power factor and voltage regulation of rectifiers with passive L-C filter”, 2001 IEEE 32nd Annual Power Electronics Specialists Conference (IEEE Cat. No.01CH37230), pp.724-729, 2001.
[3] D. L. Loree; J. P. O'Loughlin, “Design optimization of L-C filters” Conference Record of the 2000 Twenty-fourth International Power Modulator Symposium, pp. 137-140, 2000
[4] I. Nuez; V. Feliu, “On the voltage pulse-width modulation control of L-C filters”, IEEE Transactions on Circuits and Systems I: Fundamental Theory and Applications, pp. 338 - 349, 2000.
[5] Abima Justus, “High efficient power electronic inverter topology with SPWM technique for single phase trasformerless utility interactive photovoltaic system”, International Conference on Information Communication and Embedded Systems (ICICES2014), pp. 1-6, 2004.
[6] M. F. N. Tajuddin; N. H. Ghazali; I. Daut; B. Ismail, “Implementation of DSP based SPWM for single phase inverter”, SPEEDAM 2010, pp. 1129-1134, 2010.
[7] Jiancheng Song; Xiaowei Zhang; Lijun Zheng; Yunguang Gao; Yuan Song, “Simulation and experiment of three-phase voltage SPWM inverter”, 2015 IEEE 10th Conference on Industrial Electronics and Applications (ICIEA), pp. 1324-1329, 2015.
[8] Li Huan; Li Wenjuan; Cui Dongning; Automatic code generation of SPWM for single phase inverter by model-based design”, Proceedings of 2013 2nd International Conference on Measurement, Information and Control, pp. 1035-1038, 2013.
[9] Ali Algaddafi; Khalifa Elnaddab; Abdullah Al Ma'mari; Abdelrahim Nasser Esgiar, “Comparing the performance of bipolar and unipolar switching frequency to drive DC-AC Inverter”, 2016 International Renewable and Sustainable Energy Conference (IRSEC), pp. 680-685, 2016.
[10] Yiqiao Liang; C. O. Nwankpa, “A new type of STATCOM based on cascading voltage-source inverters with phase-shifted unipolar SPWM”, IEEE Transactions on Industry Applications, pp. 1118-1123, 1999.
[11] M. Azrik; K. H. Ahmed; S. J. Finney; B. W. Williams, “Voltage synchronization scheme based on zero crossing detection for parallel connected inverters in AC microgrids”, 2012 IEEE International Symposium on Industrial Electronics, pp. 588-593, 2012.
[12] Baoze Wei; Josep M. Guerrero; Juan C. Vásquez; Xiaoqiang Guo, “A circulating current suppression method for parallel connected voltage-source-inverters (VSI) with common DC and AC buses”, 2016 IEEE Energy Conversion Congress and Exposition (ECCE), pp. 1-6, 2016.
[13] S. A. O. da Silva, E. Tomizaki, R. Novochadlo, E. Antonio and A. Coelho, “PLL Structures for Utility Connected Systems under Distorted Utility Conditions”, IEEE Industrial Electronics Conference, pp. 2636-2641, 2006.
[14] M. Ciobotaru, R. Teodorescu and F. Blaabjerg, “A New Single-Phase PLL Structure Based on Second Order Generalized Integrator”, 2006 IEEE 37th Power Electronics Specialists Conference (PESC), pp. 1-6, 2006.
[15] S. A. O. da Silva, R. Novochadlo and R. A. Modesto, “Single-phase PLL Structure Using Modified p-q Theory for Utility Connected Systems”, 2008 IEEE Power Electronics Specialists Conference, pp. 4706-4711, 2008.
[16] S. K. Chung, “Phase-locked loop for grid-connected three-phase power conversion systems”, IEEE Proceedings Electronic Power Applications, vol. 147, pp. 213-219, 2000.
[17] S. A. O. da Silva, E. Tomizaki, R. Novochadlo, E. Antonio and A. Coelho, “PLL Structures for Utility Connected Systems under Distorted Utility Conditions”, IEEE Industrial Electronics Conference, pp. 2636-2641, 2006.
[18] Yash P. Bhatt; Mihir C. Shah, Design, analysis and simulation of synchronous reference frame based Phase Lock Loop for grid connected inverter”, 2016 IEEE 1st International Conference on Power Electronics, Intelligent Control and Energy Systems (ICPEICES), pp. 1-5, 2016.
[19] Wei Yongqing; Zhang Xiaofeng; Qiao Mingzhong; Kang Jun, “Control of parallel inverters based on CAN bus in large-capacity motor drives”, 2008 Third International Conference on Electric Utility Deregulation and Restructuring and Power Technologies, pp. 1375-1379, 2008.
[20] Ali Ashiebi; Ashraf Khalil; Jihong Wang, “Networked control of parallel DC/DC converters over CAN bus”, 2016 IEEE International Conference on Power System Technology (POWERCON), pp. 1-6, 2016.
[21] Yunqing Pei; Guibin Jiang; Xu Yang; Zhaoan Wang, “Auto-master-slave control technique of parallel inverters in distributed AC power systems and UPS”, 2004 IEEE 35th Annual Power Electronics Specialists Conference (IEEE Cat. No.04CH37551), pp. 2050-2053, 2004.
[22] Guido Cavraro; Tommaso Caldognetto; Ruggero Carli; Paolo Tenti, “A master/slave control of distributed energy resources in low-voltage microgrids”, 2016 European Control Conference (ECC), pp. 1507-1512, 2016.
[23] Ali Mortezaei; Marcelo Simoes; Mehdi Savaghebi; Josep Guerrero; Ahmed Al-Durra, “Cooperative Control of Multi-Master-Slave Islanded Microgrid with Power Quality Enhancement Based on Conservative Power Theory”, IEEE Transactions on Smart Grid, pp. 1-1, 2016.
[24] Santosh Singh; Sumit Ghatakchoudhuri, “Average Current Feed-Forward Control for Multi-modular Single-Phase UPS Inverters System”, 2016 7th International Conference on Intelligent Systems, Modelling and Simulation (ISMS), pp. 244-249, 2016.
[25] J. M. Guerrero; L. G. de Vicuna; J. Miret; J. Matas; J. Cruz, “Output impedance performance for parallel operation of UPS inverters using wireless and average current-sharing controllers”, 2004 IEEE 35th Annual Power Electronics Specialists Conference (IEEE Cat. No.04CH37551), pp. 2482-2488, 2004.
[26] 黃世中，“市電並聯電力轉換系統之數為控制器的研製”，國立雲林科技大學電機研究所論文，民國九十年。
[27] 王國丞，“並聯型三相不斷電系統研製”，國立台灣科技大學電機研究所碩士論文，民國九十五年。
[28] 張晉銘，“單相換流器市電併網控制系統之研製”，國立台灣科技大學電機研究所碩士論文，民國九十八年。
[29] 鍾秉學，“單相及三相市電併聯之功率轉換器研製”，國立台灣科技大學電機研究所碩士論文，民國一百年。
[30] 楊景堯，“單相市電併網之蓄電池儲能系統研製”，國立台灣科技大學電機研究所碩士論文，民國一百零二年。
[31] 李昱頡，“單相電壓源換流器之並聯控制策略研製”，國立台灣科技大學電機研究所碩士論文，民國一百零五年。