The Study On Intelligent Control System Of Electric Boiler Based On FPGA

With the development of Chinese national economy, energy deficiency has beenincreasing prominently and environmental pollution has been more and more severe. Boiler isa kind of energy conversion device, which is mainly used for heating in production and life.Currently, the principal raw material of Chinese boiler is coal. However, coal is anon-renewable resource, and the generated pollutants after burning are the main sources ofenvironmental pollution. Therefore, a better energy is needed to replace coal. Electric boiler isan energy conversion device taking electricity as the raw material, which has the advantagessuch as simple structure, small volume, high efficiency, pollution-free, stable operation, andconvenient in installation and overhaul. Moreover, the temperature of boiler is easy to control.Under some occasions with strict requirements on temperature, such as biologicalfermentation, drug storage and hospital blood bank, electric boiler is especially suitable forheating.This paper takes electric boiler as the study object, and combines fuzzy control and PIDcontrol to carry out control on the temperature and liquid level of electric boiler. In addition,temperature control adopts fuzzy PID algorithm, and liquid level control adopts PIDalgorithm. In current electric boiler control system, its control chip is mainly MCU or PLC.Targeting at the issues of low operating speed, long development cycle and instability inprogram run of such controller, this paper shall propose a solution basing on FPGA chip.FPGA was selected as the controller of electric boiler control system via the contrastiveanalysis between the internal structure of FPGA and MCU and combining with thecharacteristics of FPGA, such as high clock speed, parallel processing and good stability,which is liable to achieve intellectual control algorithm. For decreasing programmingdifficulty, liable to achieve program portability and upgrading, improving the arithmetic speedof processor, modularized FPGA programming method was adopted via the analysis andconversion on incremental FPGA control algorithm and combining with the parallelprocessing characteristics of FPGA. Taking thermostat as the control object, mathematicalmodel of temperature control system was established. In addition, fuzzy PID controller wasdesigned as per fuzzy control theory and combining with PID control algorithm, andsimulation comparison was carried out on PID controller and fuzzy PID controller of thermostat temperature control utilizing MATLAB. As per the results of simulationcomparison, fuzzy PID was identified as the control algorithm of electric boiler controlsystem. Basing on the analysis on the principle and structure of fuzzy PID control algorithm,fuzzy reasoning was achieved by adopting the method of offline reasoning and combiningwith the characteristics of FPGA in data processing. Offline reasoning has the advantagessuch as simple programming, fast speed and convenient for modifying the rules. Afterfinishing the design on the hardware circuit and driver of controller, control algorithm routinewas compiled utilizing Verilog HDL language.The algorithm and hardware driver of controller was simulated and tested on EDAdevelopment software and hardware test platform, and the test results showed that thedesigned controller is in conformity with design requirements.