分切合整數位控制與兩相或空間向量調變之三相雙向換流器性能比較

Performance Comparison between the Three-Phase Bi-Directional Inverters with D-Σ Digital Control and TPM or SVPWM

蔡昆宏(Kun-Hung Tsai)

指導教授 ： 吳財福

國立清華大學/電機資訊學院/電機工程學系/碩士(2014年)

摘要

本研究提出一個以分切合整數位控制為基礎的三相雙向併網型換流器，其中所用的調變方式，包含兩相調變(TPM)與空間向量調變(SVPWM)。此雙向換流器能夠操作在市電併聯模式、整流兼功因修正模式、功因超前模式以及功因落後模式。本研究所採用之控制法則，允許寬電感值變化，能顯著降低電感鐵芯之尺寸。分切合整數位控制，是在一個開關週期中，加總各部分電感電流變化量之後，直接推導出控制法則，可克服傳統控制法所採用的abc至dq座標轉換之限制。本文將推導兩相與空間向量調變下之分切合整控制法則，其中兩相調變包含兩種以不同零交越為區間分隔的控制法則，首先介紹本研究再研究初期採用的以電流零交越為區間分隔，接著將說明以電流零交越為區間分隔之缺點，提出以電壓零交越為區間分隔取代先前的以電流零交越為區間分隔。再推導兩相與空間向量調變的控制法則中，將利用分切合整數位控制之轉換矩陣，進一步簡化控制法則的推導過程。在設計與實現上，將量測不同電流所對應的電感值，並儲存至單晶片微控制中，以利控制器能夠每週期調變迴路增益，而本研究所採用的微控制器為RX62T使控制器能實現複雜的數位控制運算。在介紹完兩相與空間向量調變之後，將依據四項性能指標進行差異比較。本研究實作一部10 kVA三相雙向換流器來驗證以上之分析和討論。

關鍵字

分切合整數位控制 ； 兩相調變 ； 空間向量調變 ； 寬廣感值變化 ； 雙向換流器

並列摘要

This paper presents a division-summation (D-Σ) digital control for a three-phase bi-directional grid-tied inverter with either two-phase modulation (TPM) or space vector pulse-width modulation (SVPWM). The bi-directional inverter can fulfill grid connection and rectification with power factor correction and PF leading and PF lagging, and it can cover wide inductance variation, reducing core size significantly. The proposed D-Σ digital approach summarizes all of the individual inductor-current variations over one switching cycle to derive control laws directly, which can overcome limitations of abc to dq frame transformation. A universal form of the duty-ratio control laws for TPM and SVPWM is introduced and a D-Σ transformation matrix is identified for simplifying the control-law derivation. In the design and implementation, the inductances corresponding to various inductor currents are measured and tabulated into a single-chip microcontroller for tuning loop gain cycle by cycle, ensuring stable operation. The control laws based on TPM and SVPWM have been derived in detail and their feature comparison has been also presented. Measured results from a 10 kVA 3f bi-directional inverter have been presented to confirm the control-law derivation and discussion.

並列關鍵字

D-Σ digital control ； TPM ； SVPWM ； wide inductance variation ； inverter

參考文獻

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