低諧波失真DSP適應型返覆控制之交流電源供應器之研製

Abstract

這篇論文提出一種新的適應型返覆控制架構，並將其運用在交流電源供應器中脈寬調變換流器的控制上。所提出的方法是一種具有自我調整功能的週期性穩態誤差補償器，由於其本身具有適應性調整的功能，使得過去因加入週期性穩態誤差補償器而降低系統穩定性與適用範圍的特性得以改善，因此有別於一般週期性穩態誤差補償器。本文分析結果指出，所提出的方法不但可以消除換流器系統因負載週期性波動所造成的電壓失真，且不會降低系統本身穩定特性與適用負載範圍，更有另一項特點指出，在相當程度的系統動態特性差異下，所提出的方法依然可行，此點象徵著該技術運用於大量生產化產品的可行性，與產品微調技術人員的減少，以及其所引起如成本降低等種種誘因。為了驗證前述的方法，我們首先建構了一個單純以狀態變數回授法控制的交流電源供應系統，然後在控制方法上先後加入一般型返覆控制法與適應型返覆控制法，以比較此三者在穩定性、負載適用範圍與諧波消除能力的不同。文中並以德州儀器公司生產的單晶片數位訊號處理器來實現上述方法於一個額定負載2KVA的脈寬調變交流電源供應系統中。文末，我們同時以模擬與實驗的方法來說明所提理論的可行性。根據結果顯示，所提的方法不但能有效的降低因負載週期性波動，如整流性負載、相位控制型負載等所造成的波形失真至一最小程度，且擁有較高的穩定性與較大的負載適用範圍，甚且當系統動態特性發生相當程度變異時，依然有良好的表現。

A new adaptive repetitive control scheme is proposed and applied in control of a PWM inverter used in high performance ac power supply. The proposed algorithm is a steady state compensator and it can effectively eliminate distortion of inverter's output voltage which is mainly induced by periodic load variation, such as rectifier load, phase-controlled load, or a periodically switched load with unknown characteristics. Transient response of the PWM inverter can be improved by any conventional tracking controller. To verify our algorithm, pole assignment with state feedback method has been employed as the tracking controller for transient response improvement. An illustrative example is given which uses a single-chip digital signal processor TMS320C14 from Texas Instrument to realize the proposed control scheme in discrete time domain and a 2DVA ac power supply has been constucted to verify the proposed control scheme. Both simulation and experimental result are given to confirm validity of the proposed algorithm and it shows that the harmonic distortion can be effectively reduced to a minimum level of an high performance ac power supply for a rectifier load at current crest factor 3.