Development Of Intelligent High Frequency Potentiostat For Buried Steel Pipeline

In order to effectively increase the service life of buried steel pipelines,the cathodic protection method of impressed current is generally used to protect them against corrosion.Potentiostat is the core equipment of impressed current cathodic protection method,which is widely used in buried steel pipeline anticorrosion engineering.However,the potentiostat used at present is still based on thyristor potentiostat.This kind of potentiostat has some shortcomings,such as large volume,large weight,low control precision,low intelligence level and poor man-machine interface.In terms of the above problems,this article takes the corrosion protection of buried steel pipelines as the starting point,and develops an intelligent high-frequency potentiostat for buried steel pipelines based on the principle of impressed current cathodic protection.The main control chip adopts TMS320F28069,which improves the control accuracy and intelligence level of the power supply.In this paper,starting from the principle of cathodic protection of impressed current,the basic theory and control scheme that used in potentiostat are studied.According to the design index of the potentiostat,the main circuit topology is selected,and the hardware system and software system of the potentiostat are designed.Then,designing the functional circuits of each part of the hardware system,including the design and calculation of the control circuit,transformer primary circuit,transformer secondary circuit and high frequency transformer.The main circuit is analyzed and compensated for the loop by using the method of simulation-based frequency domain.The software system of the potentiostat is designed.The software system includes the main program,interrupt program,control program,bipolar PWM program,and communication program.Combined with the studying the law of potential changes along the pipeline,a pipeline potential monitoring algorithm is designed.The algorithm is able to estimate the current protected length of the pipeline and the potential at the end of the pipeline,which improves the anti-corrosion protection capability of the potentiostat on buried pipelines.Finally,relevant tests were carried out for the potentiostat to verify the equipment’s touch screen display and touch control,constant voltage,constant current,short circuit protection,no-load protection and overload protection.After testing and debugging,the potentiostat designed in this article meets the design requirements.