FPGA-based Thermostat Heat Meter Controller Design And Implementation

This paper focuses on the current situation of China's heating pipe network,using FPGA to design a thermostat heat meter controller that can achieve heat metering and heat controling.The paper first elaborates the heating supply system and the existing problems in heating supply system,as well as the development status of heat measurement in our country and abroad.To charged by area on heating bills makes the users lacking awareness of energy conservation,then cause a great waste of energy;but household metering and charging heating costs according to actual heat,can save a lot of energy.New heat meter not only can save energy,but also allows the users to regulate temperature by themselves,which facilitate the user's life.Next,the paper describes the main features,the structural principle,the development process and trends of FPGA,introduces the features and functions of the hardware description language VerilogHDL,and the system development platform Quartus II.Then the paper introduces internal structure of the thermostat and thermal measurement of the heat meter and the heat control principle.The paper selects the enthalpy method for heat calculation and determined the parameters which heat meter should measured.The parameters are water temperature,return water temperature,pressure and flow.The system selects a single-bus digital temperature sensor DS18B20 for temperature measurement.In this system the flow rate is measured by a flowmeter and the differential pressure between the import and the export of heating pipes is measured by the differential pressure sensors,then the corresponding relationship of the flow rate and the differential pressure can be found.The clogging of the flow sensor due to the poor water quality can be solved by this method.The system controls the heat by controlling the switching of the temperature control valve.The users can set the temperature by themselves,the temperature is compared with the acquisition room temperature and then formed a closed-loop control,the output PWM pulse would control the switch of the temperature control valve.Finally,the paper makes a overall planning to achieve the function,completes the design of the system according to the schematic and the hardware description language VerilogHDL.Simulation and testing are caned out with simulated tools.The paper laids foundation for the design of special chip of thermostat heat meter.