| The demand on Security and economy on energy of industry production have become important topic attended by society with development of native economy. Safe run stability and environmental protection demand of industry equipment and especially energy drive equipment have become more important. How to economize on energy and ensure security run about industry boiler in energy drive equipment had been analyzed in this paper. Industry boilers are power equipment of important energy and heat source for industrial department such as electric power, chemical industry and machinofacture, etc. Every main technological parameters of boiler during procedure must be strictly controlled for providing qualified steam to adapt loading need, because boilers are complicated controlled member. The method that can change hand control mode of water supply unit of boilers into autocontrol mode of man-machine double control was studied in this paper, which taking example for SHL20-A model steam boiler in Fu-ao Company. There are two 20-ton steam boilers in Fu-ao Company which basic control unit such as water supply unit is hand control mode. Operating crew carry through water supply of hand control by observing trichroism nilometer above boilers. Operability was bad, energy consumption also was great by this mode, and the run security of boilers would be subjected to threaten. The method controlling water supply unit by three impulses multiple regulating modes was discussed for improving operating efficiency and stability of boiler. The necessity introducing frequency conversion and economy on energy technology into control units such as induced draft, water supply and fire grate was analyzed. The control principium and method of water supply unit of boilers, VFC energy consumption principium of water pump and blower fan, and the method of frequency conversion autocontrol of water supply unit were expounded and analyzed as follows. Firstly, energy conservation principle of blower fan and water pump was analyzed using frequency conversion timing. The necessity of introducing frequency conversion and energy conservation technology in such control part as induced draft, water supply and fire grate was studied. Water supply regulating valves must be installed and flow regulation is done by aperture of valve for keeping steam drum pressure in normal value when electric machine run at fixed speed, which would let reaction speed of water pump become slow, and produce much of throttling loss. If electric machine was drived by frequency conversion timing, different pressure demand could be satisfied through changing rotate speed of electric machine, which would save accessional wastage due to resistance of valve, and carry out the purpose of energy conservation. The change of response speed of pressure was faster by the method of timing than by changing valve opening, which would accelerate reaction of auto regulating system about water line of steam drum of boiler, and which would improve performance of water supplyregulating system of boiler. After regulating drive using frequency conversion timing, controllability was improved, response speed was fasted, control accuracy was also improved, which improved control performance of whole system, improved mode of operation of system, effectively alleviated wear of impeller and bearing, prolonged useful life of device. in addition, improvement of technological conditions could also produce great economic benefit. Secondly, analysis and study on regulating unit of water line in steam drum The role of water supply autocontrol regulating unit was that water supply capacity could adapt the change of evaporation capacity, water supply capacity and evaporation capacity could keep balance, and water line of boiler could keep stated range. First disturbing on controlled member of water line of steam drum was analyzed. There were several factors affecting the change of water line of steam drum: disturbing of water supply capacity; variety of steam load; variety of burning capacity; variety of steam drum load. Thereinto such disturbing factor as variety of steam drum load may be merged into rest disturbing factor to consider. Variety of burning capacity had additional regulating system, which could be overcome when fluctuating, so this factor need not consider hereon. Variety of steam load is not controllable factor that can change according to need of consumer. Thus it can be seen that only water supply capacity can become regulating parameter. So the control on water supply capacity ofboiler plays an important role in whole run systems of boiler. Secondly the effect of steam load on water line could be comprehended through analyzing dynamic properties of water line of steam drum. Abrupt variety of steam dosage would produce a phenomenon of falsehood water line when charge of fuel is unaltered, so how to avoid phenomenon of falsehood water line should be emphasized. It was known that three impulses complex regulating unit was the best control mode through contrast analysis among single impulse, double impulse and three impulse complex regulating unit. three impulse complex regulating system was that water supply pressure signal was introduced on the basis of intrinsic water line regulation of steam drum and steam flow regulation. Among which water line was main impulse, and steam and water supply were accessory impulse, which made up a feedforward-concatenation complex regulating unit which solved lagging great inertia of water line of steam drum, rapidly reacted small inertia disturb, and inhibited the effect due to disturb of steam load through feedforward compensation of steam flow. Put together, application of three impulses complex regulating mode was very necessary for water supply unit of boiler. The basic algorithm of this complex regulating mode was studied, simplification treatment of regulating mode was done, and setting of basic parameters was analyzed on this basis. Thirdly, basic scheme about autocontrol of frequency conversion timing of water supply unit in boiler were analyzed.Autocontrol schemes of frequency conversion were analyzed and studied on the basis of concrete demand about three impulse complex automatic regulation mode of water supply unit of boiler and energy conservation principle of frequency conversion timing in water pump and blower fan. Total distributed control mode of programmable controller was adopted. Microcomputer mainly carried out management function, visually displayed site status, possessed such functions as warning and record; However PLC of hypogyny computer had mature technology, could control execution of procedure at PLC, mainly carried out control function, incepted set-up parameter of epigyny computer, not depended on autocontrol of epigyny computer, which solved many problems such as hand operation error, work fallibility and energy waste. Field data used for detecting and controlling this least control unit were studied in the unit, such as steam drum flow, steam drum pressure, steam drum liquid level, water supply pressure, etc. Setting of procedural parameter PID was critical problems during control. Because the number of amount of used steam and magnitude of steam pressure decide the magnitude of water supply flow and water supply pressure, procedural parameters PID were repeatedly adjusted to appear the best control process for steady run of system which do not appear big fluctuation so as to creating effect on production. It was known that boiler water supply was one of important link during boiler run by above content, which stability and reliability is referred to stabilization and security of production run of whole boilersystem and whole enterprise production. Using complex control mode is necessary for boiler water supply, which can obtain the best control effect. Through analyzing frequency conversion autocontrol method of on boiler, Autocontrol of procedure on water supply unit had been carried out, which not only strengthened safe run stability of boiler, but also had obviously improved production efficiency and effect of energy conservation. Design reason and method of this system have also sure contribution on control of other similar process such as negative pressure regulating unit of hearth and steam pressure regulating unit that have not be particularly introduced in this paper in burning control system of boiler.
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