Research Of The Road Tunnel Ventilation Energy-saving System Based On Intelligent Control Technology

The tunnel is a relative enclosed road section in the road. The poison gases and small particles that exhausted by passing vehicles can cause air pollution in the tunnel. For the long and large tunnel, the overrunning poison gases are able to threaten the vehicle personnel's health and the excessive smog can affect the drivers'driving safety. In order to purify the air in the tunnel and make the pollution concentration in the tolerance range, machinery ventilation that controls the jet fans must be adopted.The road tunnel longitudinal ventilation system has strong time-varying, non-linear and large delay characteristics, thus a precise mathematical model which controlled by using traditional control methods is difficult to gain. Meanwhile under the situation of lacking energy in our country, the soaring operation expense of tunnel ventilation system (TVS), that is a key problem in the tunnel construction, should be conquered as soon as possible. A new control method by using intelligent control technology (ICT)for TVS is proposed in this paper.Firstly, the TVS is controlled as a"black box"by using fuzzy control technology. With experts'or operators'knowledge and experience, a set of control rules are formulated and then these rules are adjusted and optimized in terms of a special way which is called the best rule sorting independence. Meanwhile the fuzzy logic controller compares real-time measured and desired levels of pollutants, and then sends a set of instructions to control the jet fans by inferences.Secondly, since the TVS is a large delay system, the neural network (NN) technology which has a capability of self-adaption and self-learning is used to build a NN online control system that can forecast the volume of tunnel traffic. The jet fans can be pre-started to some extent in the different time areas through the prediction of traffic flow, so the control model can be optimized, and the control automaticity and control accuracy of system can be enhanced; thus the frequency of jet fans'starting can be reduced, and the goal of energy conservation can be achieved as well.Moreover, various frequency drive (VFD) technology is introduced to control the fan motors'speed and action. VFD can raise the ventilation equipments'starting condition, and prolong the lives of TVS, and save considerable electric power.Finally, the paper analyses the energy conservation control regarding the TVS by using ICT and VFD respectively. Conclusions are then made that the ICT can achieve the predetermined control target by saving about 17% energy compared to the traditional control, and get an obvious energy-saving effect by using VFD, so the tunnel ventilation energy-saving system based on the intelligent control technology can reach an optimization on control efficiency and control cost theoretically.