Research And Design Of Low Voltage And High Current Water Treatment System

The circulating cooling water system is an important part of the industrial production facilities.In the industrial production process of electric power and chemical industry,water,as heat exchange medium,is widely used in the circulating cooling water system.In the long-term operation process,circulating cooling water is likely to cause equipment scaling,breeding of microorganisms,equipment corrosion and other hazards,so it is necessary to improve the governance,otherwise it will seriously affect the safe and stable operation of the system,and then increase water consumption and sewage discharge.As a new water treatment technology in recent years,low voltage and high current water treatment system is gradually becoming a research hotspot.In this thesis,through the research on the operating principle and structure of the low voltage and high current water treatment system,the work efficiency of the system can be further improved by the main circuit adopts ZVZCS PWM DC/DC full-bridge conversion circuit based on synchronous rectification technology,that is,soft switching state can be achieved in both lead arm and lag arm to reduce the system loss in the high frequency state;and synchronous rectifier can be used to replace the traditional full-wave rectifier mode in the side rectifier.The system adopts STM32F103RCT6 chip as the main controller.According to the design requirements of low voltage and high current water treatment system,the corresponding circuit model is designed based on this and the selection basis of the relevant parameters of the main circuit is analyzed in detail.On the basis of the working requirements of the main circuit IGBT switch tube and the secondary synchronous MOS tube,the IGBT drive circuit and the synchronous rectification drive circuit are designed.The temperature sampling circuit,voltage sampling circuit and current sampling circuit are designed by considering the monitoring requirements of the low voltage and high current water treatment system.The ZVZCS full-bridge circuit model based on synchronous rectification technology is simulated and analyzed by PSIM simulation software.The phase shifted control mode is realized by constructing numerical logic circuit.Based on these two points,the complementary conduction between the super lead arm and the lag arm can be realized at the same time.The simulation analysis of the main circuit shows that the leading arm can realize ZVS state and the lagging arm can realize ZCS state.The system can stably output the low voltage and high current of 15V and 400A,which can achieve the established design requirements well.In order to cope with high current output,this design adopts the output form of double transformer in parallel connection on the secondary side of the primary side,which can realize high current automatic current sharing well.By the comparation between the synchronous rectification output model and the traditional full-wave rectification output model,it is easily to verify that the synchronous rectification output model has higher power efficiency.In view of the above design ideas and schemes,the experimental prototype of the low voltage and high current water treatment system is builted and its electrical performance is tested.After running for a period of time in a chemical plant,the test result shows that the redox reaction between the anode and cathode plates can realize the pre-precipitation of scale ions,the production of active chlorine and various active chlorine intermediates for sterilization and algae elimination.Compared with the traditional chemical reagent method,the low pressure and high current water treatment method without any additional reagents,is clean and environmentally friendly,truly realizing the"water treatment with water"and the economic cost saving is obvious.