根據再生制動時直流母線電壓的變化狀況調節逆變器的輸出功率大小，將直流母線電壓恒定在某一設定值范圍內，整機對外呈現電流源特性。
逆變器主要由直流接觸器、逆變單元、濾波電抗器、交流接觸器等部分組成，如圖1所示，可實現逆變裝置自動投入、撤出、濾波及檢測等功能。
逆變裝置主回路拓撲
逆變裝置主回路拓撲
圖1 逆變裝置主回路拓撲
當車輛再生電制動且制動能量不能被其它車輛或用電設備消耗時，再生制動能量吸收逆變裝置將該部分的能量，根據直流母線電壓的變化自動調節逆變單元的輸出電流大小，逆變為與電網電壓同頻、同相的交流電送回電網。
逆變主電路主要實現逆變吸收、自動并網及逆變電流調節等功能。逆變主電路由多路獨立的逆變單元及控制裝置等組成，逆變單元采用IGBT作為開關器件，控制裝置通過PWM調節控制每條支路IGBT通斷。并根據實際再生制動能量的大小調節并網電流，充分滿足車輛的再生制動功能。裝置具有過壓、過流、溫度、短路等多種保護功能。
逆變裝置的單元采用三電平拓撲電路，如圖2所示。逆變輸出電壓波形、輸出電流波形分別如圖3、4所示。
功率單元拓撲結構
功率單元拓撲結構
圖2 功率單元拓撲結構
3.3顯示設定
顯示裝置采用彩色觸摸屏，通過觸摸屏操作，實現對系統運行狀態的實時顯示、用戶級參數修改等功能。同時對故障進行顯示和記錄，欠壓、過壓、過流、過熱等保護值，以及逆變裝置啟動閥值等參數可通過觸摸屏進行設定。
3.4通信功能
控制系統采用標準的數據通信口，采用RS485接口，數據通信協議采用具有良好的通用性和開放性Modbus協議。, which not only overcomes the shortcomings of unstable analog control and low precision of traditional frequency conversion in this industry, but also ensures the independent operation of the frequency converter and reduces the interference to the system;
U the system reserves Industrial Ethernet interface and supports standard Modbus TCP / UDP and other protocols to facilitate access to factory level production management of cadre production line, and can also be accessed to production management through serial port. The vertical direction with the corrugated board is called the longitudinal direction. The longitudinal cutting indentation machine is mainly used to cut and trim the edges in the longitudinal direction according to the specifications of the board, and indentation the crimping groove at the rolling folding part (as shown in the following figure, the red line is the indentation between the shaking cover and the height of the box in a single sheet, and the blue line at the edge is the cutting mark between multiple sheets). The products produced have become the packaging carton we use daily after
