直流微電網雙向換流器之直流匯流排穩壓控制策略

Control Strategy For DC-Bus Voltage Regulation Of Bi-Directional Inverters In DC-Microgrid

徐培開(Hsu, Peikai)

指導教授 ： 余國瑞

國立中正大學/工學院/電機工程學系/碩士(2012年)

摘要

本研究提出於直流微電網中，利用雙向換流器進行穩壓的兩種控制方法，可平衡直流鏈電力。首先取得直流鏈之電容值，再根據此電壓變化量之變動速度，配合線性穩壓關係的控制機制，決定調整電流指令的方法，來調節其對應的穩態電壓範圍準位。賣電模式則穩在較高準位，買電模式則穩在較低準位，目的為避免因為負載變動，造成買、賣電模式的頻繁變動，也可降低過壓、欠壓的保護啟動頻率。此直流微電網之穩壓方法，是根據電壓變化量之變動速度來決定所使用之週期調整控制法，當直流負載變動緩慢時，則使用可同時應用於單、三相雙向換流器的一週期調整控制法；當直流負載變動急遽時，則使用應用於單相雙向換流器的四分之一週期調整控制法，以及應用於三相雙向換流器的六分之一週期調整控制法，來達到快速穩壓的機制，藉此維持系統的穩定性，及提高換流器的可靠度。接著建立此兩種穩壓方式的電腦模組程式，來模擬直流微電網負載變動時之電壓電流變化情形，最後將電腦模擬結果與實驗波形進行驗證。

關鍵字

雙向換流器 ； 直流穩壓 ； 直流微電網

並列摘要

This thesis presents dc-bus voltage control for one-phase and three-phase bi-directional inverter in dc-microgrid applications.With the proposed control, the inverter can adjust current commands to balance power flow. These two approaches are one line-cycle regulation approach (OLCRA) for two bi-directional inverter and quarter line-cycle regulation approach(QLCRA) for one-phase bi-directional inverter and one-sixth line-cycle regulation approach (OSLCRA) for the three-phase bi-directional inverter, which are based on the linear power management scheme. The first one can control dc-bus voltage to track a linear load line every line cycle, according to a linear relationship between the dc-bus voltage and the inverter inductor current, and the second one adjusts current command every quarter line and one-sixth line cycle to adapt to load variation. The inverter regulates the dc-bus voltage to a higher level when the bi-directional inverter injects more power to the ac grid, while it will regulate the bus voltage to a lower level when it draws higher power from the grid. The two approaches together can reduce the frequency of over/under voltage protection and improve the operational reliability and availability of the dc microgrid without increasing dc-bus capacitance, especially under heavy load requirement. Then the models are established for computer simulation, and a dc-bus voltage regulator is designed to solve the problem of dc-bus load variation. Finally, computer simulation results are compared with experimental waveforms to discuss its effectiveness.

並列關鍵字

Bi-directional ； DC Voltage Regulator ； DC-Microgrid

參考文獻

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