應用反覆控制理論於三相交直流轉換器功率因數控制之研究

Abstract

本文提出一種可應用於高功率三相交直流轉換系統之數位式主動功 因修正技術 ，使得系統在低頻切換的條件下，仍可達到高功率因數的要 求。控制架構採用雙迴 路控制方式，包含電流內迴路與電壓外迴路。在 電流迴路方面，藉由預測電感電流 之變化以產生所需之控制力，使系統 具有快速的動態響應。此外並加入一個輔助的 反覆控制器，來消除因開 關切換頻率降低所產生之週期性電流諧波。在電壓迴路中 ，則以PI控制 器來進行輸出直流電壓的調節，同時利用負載電流之回授補償，來抑 制 系統因負載變動所造成之輸出電壓擾動，達到低輸出阻抗的目的。實驗系 統是建 構在以雙DSP(TMS320C14與TMS320C52)為基礎之數位控制板，配合 以IGBT為核心的智慧型功率模組，來進行實測驗證。模擬與實驗結果顯示 ，本文所提之反覆控制理論 應用於三相交直流轉換系統，能夠大幅降低 系統於低頻切換時之穩態電流諧波及誤 差，驗證了其在功因改善上的可 行性。 This thesis proposes a fully digital active power factor control scheme applied to high power three-phase AC-DC converters, which can meet the requirement of high power factor even under low switching frequency. The control system is constructed in a multi-loop control configuration. In the current loop, a predicted current control method is proposed to ensure the system to achieve fast dynamic response. At the same time, an auxiliary repetitive controller is added to eliminate periodic current harmonics caused by switching. In the voltage loop, a PI controller is used for the regulation of the output DC voltage. In order to achieve low output impendence requirement, the system employs the feedback of load current to minimize the output voltage distortion caused by load variations. A dual DSP- based digital control board and an intelligent power module (IPM) based voltage source inverter are constructed to realize the proposed control algorithm. Simulation and experimental results are given to verify the effectiveness of proposed repetitive control scheme for power factor correction of 3-phase AC-DC converters.