根据再生制动时直流母线电压的变化状况调节逆变器的输出功率大小，将直流母线电压恒定在某一设定值范围内，整机对外呈现电流源特性。
逆变器主要由直流接触器、逆变单元、滤波电抗器、交流接触器等部分组成，如图1所示，可实现逆变装置自动投入、撤出、滤波及检测等功能。
逆变装置主回路拓扑
逆变装置主回路拓扑
图1 逆变装置主回路拓扑
当车辆再生电制动且制动能量不能被其它车辆或用电设备消耗时，再生制动能量吸收逆变装置将该部分的能量，根据直流母线电压的变化自动调节逆变单元的输出电流大小，逆变为与电网电压同频、同相的交流电送回电网。
逆变主电路主要实现逆变吸收、自动并网及逆变电流调节等功能。逆变主电路由多路独立的逆变单元及控制装置等组成，逆变单元采用IGBT作为开关器件，控制装置通过PWM调节控制每条支路IGBT通断。并根据实际再生制动能量的大小调节并网电流，充分满足车辆的再生制动功能。装置具有过压、过流、温度、短路等多种保护功能。
逆变装置的单元采用三电平拓扑电路，如图2所示。逆变输出电压波形、输出电流波形分别如图3、4所示。
功率单元拓扑结构
功率单元拓扑结构
图2 功率单元拓扑结构
3.3显示设定
显示装置采用彩色触摸屏，通过触摸屏操作，实现对系统运行状态的实时显示、用户级参数修改等功能。同时对故障进行显示和记录，欠压、过压、过流、过热等保护值，以及逆变装置启动阀值等参数可通过触摸屏进行设定。
3.4通信功能
控制系统采用标准的数据通信口，采用RS485接口，数据通信协议采用具有良好的通用性和开放性Modbus协议。, 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
