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本工作中研制了一种用微机直接控制的恒电位阴极保护电源.其基本原理完全不同于现有恒电位仪的反馈控制。它定时对阴极电位采样,根据与给定值的偏差,通过可变比例控制算法,调整可控硅电源的输出电压,并保持这一输出电压直至下一次采样。在这种控制方式下,除电位采样和控制算法以外的大部份时间内,微机处于“闲置”工作状态,并且参比电极与控制系统无关.这样的保护电源可望方便地扩展到多通道巡回控制,用单一电源对多阳极系统实施恒电位阴极保护。

A microcomputer based system for impressed current cathodic protection was developed on the basis of the fact that under steady state condition prot- ection potemtial will not change much if voltage of d.c.supply is maintained.Its operating principle is entirely different from that of available industrial potentiostat,in which closed-loop feedback control is continuously executed. Potential control with the new system is achieved by periodic adjustments of d.c.power output.Potential received periodically from a sensing electrode is compared with a preset control value and their difference is fed into an A/D converter.Then the digital signal goes into microcomputer and a result- isng voltage proportional to potential difference is sent to thyristor circuit to correct the d.c.output voltage.Steady state condition is reached by suc- cessive adjustments.The operation of the system was demonstrated by cathodic protection of mild steel at +0.1V vs zinc reference electrode in portable water.When a sampling period of 0.7second was taken,a potential control accuracy of +10 mV was obtained.The most attractive feature of this new design is that it could be easily extended to multi-anode system.Iu this case each anode is driven by its own d.c.power module and is under computer control periodically.