Design Of A Control And Transceiver Module In HVAC System

The HVAC controllers which originally dispersed throughout the building arenow can be integrated to operate as a system through a wireless network; On the otherhand, smart grid and cloud computing technology in the ascendant; the integration ofHVAC control system and these two technologies is a big and untapped market. Toachieve this goal, we need to develop a device that can support the interoperability ofexisting products and the Internet. This device will parse the private wireless protocolnetwork message, then repackage the message and send it to a specific server on theInternet. And so a variety of high value-added features can be possible.This paper describes the hardware design of the transceiver module, consists ofblock function diagram design, the detailed circuit design, power integrity analysisand technical problems and solutions encountered in product design. During design ofproduct block function diagram major electronic components have been selected: themain control chip, external SDRAM, and Ethernet driver; product architecture needalso be able to achieve the feature of in application software upgrade. In addition,possible requirements of the product features in the next few years are also beconsidered. Detailed design of the entire circuit, including the system powerconsumption estimates, and power supply design accordingly, in order to ensure thesystem chip can go into the normal working state, design of the power-on sequence,reset sequence are also be done. Power Integrity Design solves the power problemsfound in the product design works, analysis of the power integrity, and ultimatelyimprove the reliability of the product. During product design some technical problemsencountered are also be introduced, including product electrostatic discharge testfailures and solutions, as well as network communication timeout and solutions.Many design tools are implemented in the product design work such as Mathcad,Spice, and the use of Monte Carlo simulation, circuit time domain analysis andfrequency domain analysis and other analytical methods improve the quality of thedesign.