伺服應用三相直流交流電網回生轉換器設計

Abstract

回生轉換器(Regenerative converter)因其雙向功率流控制、功率因數調節、低電流諧波等優點，被廣泛應用於高功率伺服馬達驅動設備。在現今許多工業規範對於電能使用皆有嚴格要求的環境下，回生轉換器已成為取代傳統二極體橋式轉換器的首選。 傳統回生轉換器控制方法，必須加裝電壓感測器在電網側以獲得電網電壓相位資訊，並且確保電壓感測線與轉換器輸出在相同相位上，否則轉換器會根據錯誤的相位進行切換，進而導致過電流的問題產生。然而在實際應用中電壓感測三相線錯接是一個常見的問題，為解決此問題本文提出基於轉換器輸出側電壓的控制方法。透過本文提出之控制方法可將電壓感測器與輸出接口進行整合，以避免電壓感測線錯接之問題。 為了對回升轉換器控制方法進行驗證，本文透過 3KW 馬達負載機對回生轉換器進行各種負載狀況的實驗，並將其與外接相電壓感測的控制方法進行暫態和穩態性能比較。經由實驗驗證，本文提出之控制方法對比外接電壓控制架構具有相近的控制性能，並且符合 IEC-61000-3-2 Class A 之電流諧波規範。

The regenerative converter has advantages of bidirectional power flow control, power factor regulation, and low current harmonics. It has been widely applied in high-power servo motor drives. Considering the industrial application with strict power usage requirement, the regenerative converter has become the preferred candidate comparing to traditional diode-based converters. Conventional control methods for regenerative converters require three voltage sensors connected to the grid side in order to obtain instantaneous voltage feedback for regenerative control. It is crucial that the voltage sensing power line should be the same phase with respect to the converter output line. Otherwise, the converter can be unstable due to the incorrect phase information. For practical applications, the misconnection of the voltage sensor phase line and gird phase is a common problem. In this case, this paper proposes a grid control system by integrating the voltage sensor inside the inverter output. By directly connecting the converter output phase voltage to the grid, the voltage sensor line misconnection can be avoided. Based on the converter's output voltage to address this issue. Experiments are conducted based on a 3 kW motor load machine under various load conditions to validate the proposed control method. Experimental results demonstrate that the proposed control method exhibits similar control performance to the traditional control system with outside voltage sensors. The proposed regenerative converter also complies with the IEC-61000-3-2 Class A specifications.