The Design Of A Numeric-control High Frequency Switching Mode Power Supply Potentiostat In Cathodic Protection

Along with the enhancement of anticorrosion awareness, cathodic protection technology is becoming more and more popular. One important technology is cathodic protection with current limiter. The core of this technology is DC power supply, namely, potentiostat. from the Potentiostat form,this are SCR, magnetic saturation and CNC high-frequency switch. For SCR and magnetic saturation potentiostat, larger volume, larger ripple quotiety, less control accuracy and less efficient (less than 70%) is not easy to digitize. Remove these factor, for Magnetic saturation potentiostat, less than 20% of the rated power output can't been controlled. For CNC high-frequency switch potentiostat, It is smaller volume and smaller ripple quotiety, high precision control and high efficiency (above 90%).Because the main circuit is not stable and the problems of temperature rise and drift can not be solved well, the potentiostat has not been used widely. In this paper report, used high-frequency switch and CNC technologies, one potentiostat with cathodic protection has been designed, which can solve those problems above well.In this paper, author first sums up potentiostat conditions, describes several cathodic protection rules, analyzes the application status of current potentiostat, author finds out which problems should be solved and makes sure which technologies should be used. The potentiostat with cathodic protection can solves these problems, such as the instability of main circuit, the temperature rise and drift. At the same time, this design is requested to satisfy the property demand of potentiostat's corresponding load, namely, the output range of potentiostat is every large, from low current and low voltage at first to high current and high voltage at the end. The core of this design is high-frequency switch and CNC technologies. In rectify part, IGBT is used. And in control part, DSP technology is used.After analyzing this information, one cathodic protection potentiostat is designed. This device not only can detect protection object, but also can monitor the whole process, which including automatic sampling, automatic adjustment mode, current and voltage limiter, data retention and transmission, anti-jamming technology, temperature and fans control, temperature drift and compensation. According to the main design scheme and modular design idea, author makes a detailed analysis of the main circuit, control circuit, panel design and software design.This paper has several main innovations, such as:Using CNC and high-frequency switch technologies together; Using anti-jamming technology; This cathodic protection potentiostat has RS-232 and RS-485 communication interface. It can also use GSM/GPRS wireless communication; This device can run parameters and has the functions of data automatic sampling and data saving. These functions can maintain data in exceptional circumstances; Function of smart sound and light alarm, which can actually judge electromotive force overflow, output current/voltage overflow and temperature overflow. When alarming, the alarm reason can also be shown; This device uses Chinese LED with film button.