二次回路及控制
控制系统由控制器，IO板和人机界面组成。控制器由三块光纤板，一块信号板，一块主控板和一块电源板组成。各部分之间的联系如下图HIVERT变频器控制系统结构图所示。
图3 HIVERT变频器控制系统结构图
2.变压器柜
高压水冷变频器采用干式移相隔离变压器。绝缘等级为H级。额定容量为12500kVA。
3.功率单元柜
6kV变频器每相6个功率单元串联，单元采用前侧排列方式。同相的6个单元由铜排或电缆串联并且三相的第一个单元短接成Y接中心点，三相的第六个单元即为变频器的三相高压输出。功率单元额定电压690V，变频器的额定输入/输出电压为6kV。正面右侧为二次控制室，安装有控制器、电源开关等，用户二次接线端子也布置在控制室内。
功率单元采用水冷设计，安装在导轨上，由两个M8的螺钉与导轨固定。单元柜后侧为水循环管路，把功率单元内产生的热量带到水-水热交换器，由外水循环系统将内水热量带走。柜门内侧装有行程开关，用于柜门连锁，柜门打开时将发出告警。
3.1单元柜水冷循环系统
水冷分内循环和外循环两部分。内循环部分，变频器功率单元采用水冷板散热，去离子水通过管道进入水冷板，将IGBT等功率元件热量传递给去离子水后，由去离子水带走，进入水-水热交换器，水-水热交换器通过和外循环水换热，把热量由外循环水带走，冷水进入单元水冷板继续循环。
4.冷却方式
据现场实际情况、投资、运营、可靠性及维护成本，采用风-水冷却系统方案。
4.1 风路循环
冷却变频器后的热空气由风机从柜顶导出，通过风道循环至换热器，换热器中通有冷却水，从而使空气得以冷却降温，冷却降温后的空气再次进入变频器对变频器进行冷却，如此进行循环冷却。to illustrate with pictures with SIMATIC s7-1200 control cabinet or products.
As the master station, cpu1214 communicates with 11 sub stations in real time through cm1241 RS-485 communication module in the figure What impact does the use of SIMATIC s7-1200 controller have on projects, products, individuals and companies.
The new generation of reflow soldering equipment of RND / rad, with SIMATIC s7-1200 as the system control core, has been introduced to the market since the spring of 2010. So far, hundreds of equipment have been in operation, and no PLC fault or bad phenomenon has occurred. The whole control system is stable and runs well, and the performance also fully meets the control needs of this series of equipment. This shows that the decision to choose s7-1200 as the control system is correct. It is believed that the good performance of s7-1200 will also create greater benefits for the company.
Through the design of this project, I will have a deeper understanding of Siemens products and have more confidence and expectations for Siemens products.
Compared with S7-200 or other brands of PLC in the same file,
