以微處理機實現空間向量脈寬調變技術之換流器

Abstract

本論文提出利用一個單晶片微電腦MCS89C52實現空間向量脈寬調變( SVPWM)技術之三相電壓源換流器。由於僅使用一顆8位元單晶片微電腦， 此換流器不僅體積小而且經濟實惠。在此換流器中，我們利用微電腦的三 個計時器及中斷方式實現每個切換週期所需的三個SVPWM基本向量，因此 主程式可以即時(real-time)計算出要實現下一個空間向量所需的資料。 為了減少微電腦的運算，弦波函數以查表方式求值。由於輸出電壓向量採 固定切換週期，因此即使頻率急遽變化，電壓相位仍保持連續。模擬及實 驗以驅動一1 HP之感應馬達為例，其結果驗證所提電路之實用性。 This paper presents an implementation of a three-phase voltage source inverter with space vector pulse-width modulation (SVPWM) by using a MCS89C52 single-chip microcomputer.Since only one single-chip 8-bit microcomputer is used, the proposed inverter is compact and cost-effective. The implemented program combines three timers in the microcomputer with the interrupt scheme for realizing three basic vectors of SVPWM during one switching interval,such that the main program can compute the required data for realizing the next space vector in real time. Tables and table look-up technique are created and employed to avoid the evaluation of the sinusoidal function and reduce the computational burden of the microcomputer. Since the switching interval is fixed in our inverter for realizing one space vector of the desired output voltage, the phase angle of the output voltage continues even the desired frequency changes abruptly. Among all SVPWM techniques,Simulation and experimental results for driving a 1 HP induction machine are given to demonstrate the usefulness of the implementation.