| Electromagnetic induction heating is an energy-saving and pollutionfree heating technology.The electromagnetic furnace is an important application of electromagnetic induction heating technology.Nowadays,when heating with an induction cooker,the temperature of water or food in the pot cannot be accurately obtained,so the heating method of constant power at fixed time is often used.This heating method can’t automatically adjust the output power according to the temperature of water or food in the pot,which is easy to lead to "excessive" output of power,resulting in a certain waste of energy.Therefore,boiling water and boiled food are choosed as the research objects in this paper.This paper uses the double infrared temperature measurement structure to measure the temperature of the pot wall,and constructs the heat transfer model between the pot wall and the water in the pot.Finally,the water temperature in the pot is obtained,and BP neural network PID algorithm is used to realize the control of power.Firstly,aiming at the problem of obtaining the water temperature in the pot,the model of the heat transfer between pot wall temperature and the water temperature in the pot are deduced and constructed theoretically.The difficulty of using this heat transfer model lies in the selection of the temperature measurement area of the boiler wall.This paper takes water as the heated object,and uses ANSYS software to analyze the thermodynamics of the boiler heating model using different heating power.In addition,the temperature distribution of pot wall under different heating power on boiling the water was obtained by infrared thermal imager.Through the analysis of ANSYS software and the actual temperature measurement of infrared thermal imager,it is found that the area below 6mm from the bottom of the pot is greatly affected by the temperature of the pot bottom,and the temperature of the pot wall decreases gradually from 6mm to 22 mm from the bottom of the pot,but the temperature distribution of the pot wall on 22 mm is relatively uniform.Based on this result,an infrared temperature measuring device is designed to collect the data of equal spacing temperature points on the boiler wall,and the temperature distribution model of the boiler wall under different heating power is established to further verify the results.Finally,the double infrared boiler wall temperature measurement method is determined,and the maximum difference between the water temperature obtained by this method and the actual water temperature is 1.03 ℃,and the average difference is 0.45 ℃.Secondly,an improved induction cooker prototype is designed to verify the design scheme of this paper.The design of induction cooker prototype starts from two aspects: hardware and software.In terms of hardware,each circuit is designed according to the needs of improving the induction cooker prototype,and the circuit of induction cooker prototype is simulated and analyzed by using Multisim circuit simulation software.In terms of software,based on the existing function program of the induction cooker,the output power algorithm of the induction cooker is improved,and the dual pulse width modulation is used to control the power output,which solves the problem that the induction cooker can’t be heated continuously with low power,and realizes the linear correspondence between the PWM output duty cycle and the output power.In addition,MATLAB software is used to simulate and compare the conventional PID and BP neural network PID control algorithm,which verifies that the BP neural network PID algorithm can be applied to the induction cooker heating system and can achieve more accurate temperature control.Finally,the improved induction cooker prototype is used to boil different foods to verify the energy-saving effect.Set different output power to boil water and measure its power consumption.The most energysaving heating power is 1812 W.In the heating stage without PID algorithm,this power is used for energy saving.In this paper,the market induction cooker,the induction cooker prototype with conventional PID algorithm and the prototype with BP neural network PID algorithm are used to heat various kinds of food with water as the heating medium,and their power consumption is measured.The test results show that the power consumption of the prototype with conventional PID algorithm and the prototype with BP neural network PID algorithm are 51.41% and 49.89%of the market induction cooker respectively,which are significantly lower than that of the market induction cooker,and the power consumption of the prototype with BP neural network PID algorithm is 1.52% lower than that of the prototype with conventional PID algorithm.Therefore,using BP neural network PID algorithm to control the improved induction cooker prototype is more energy-saving. |
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