| Gas water heater knows as water heater,it is a gas application by burning the fuel gas to product heat,then transfer heat to cool water through heat exchanger.At present,there are four classes water heater in the market;they are flue type,forced exhaust type,ore-balanced instantaneous type and condensing water heater.The designed self-power generation water heater has lots of differences compared with the traditional gas water heater.The power supply of system comes from the thermopile which heats by the pilot gas burner.The pilot burner is always on after ignited by piezo-lighter,one function of the pilot burner is providing the power supply to control unit by heating the thermopile,and the other function is igniting the gas from main gas valve when main gas valve turns on.The function of main gas burner is heating the cool water.Design and implement methods of power supply module,temperature detection module,gas valve drive module and communication module are described in detail in the paper.Self-excitation switching power supply has high performance with simple circuit.Double thermistor temperature detection circuit has high accuracy and good reliability.Charge pump circuit which applied in the gas valve drive circuit makes sure the security.In addition,design methods of other modules such as controller design module,display module are also involved in this paper.The test issues and solution in the system testing are listed in this paper.For the ESD issue,the “block” and “drain” methods are combined in the design.The restart issue is solved with additional voltage regulator circuit in the power supply system.The CAF issue which happened in the reliability test has been identified and solved through the X-ray check and cross section analysis,and give some comments and solutions.The test result shows that self-power generation water heater works normally and implement the self-generating electricity function successfully.More comfort,more security,more reliability. |
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