| The energy consumption of Heating Ventilating and Air-conditioning(HVAC) occupies more than 60 percent of energy consumption of the whole building in the intelligent buildings.Most HVAC controllers use PID control strategy with multiple control loops,so how to regulate PID parameters immediately in every controller loop,and make them matching with current operating load of HVAC system is a crucial problem to reduce energy consumption.The parameters of HVAC controllers are usually configured by experienced engineers,but most HVAC controller loops themselves have some characteristics,such as, nonlinearity and time-variety,so these parameters could merely arrive at the optimal control which matches with the operating load at a time,but the operating load of HVAC system is affected easily and alters every time.How to configure PID parameters of all the loops on line is very difficult.This thesis is based on the LonWorks technology,design and complete the HVAC controllers auto-tuning method,solve the problems of multiple controllers auto-tuning in the HVAC system of auto-control buildings.It evaluate on the control performance based on the integral of square error in unit time,design and complete the data exchange module in the bottom with DDE technology and LonMaker,monitor every single controller's performance on the LonWorks Network.Then do the relay-feedback experiment for abnormal controllers online by the upper optimization computer.Design and complete the PID parameters auto-tuning application software based on Visual C++ and SQL Server 2000 DataBase.The experiment results shows that it could accurately locate abnormal control loops and do the PID auto-tuning strategy which is based on relay-tuning experiment if the work condition have changed at running time,finally which would make these abnormal controllers match with current operating load,attain the best running state, improve control quality and reduce the energy consumption. |
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