| The rapid development and progress of the industry in today’s society,promoted people’s living standard has been improved. Air conditioning has become a necessary part in people’s daily life and work. Therefore, the central air conditionings are everywhere in each of a modern building, and most of the energy consumption in a modern building also comes from the central air conditioning. Because we exist many imperfections in central air conditioning design and management, the central air conditioning has a huge potential for energy saving. At present, because we have not formed a systematic management of central air conditioning, its automatic control level is too low, from the perspective of the whole system,how to optimize various parameters of the central air conditioning in its running process, making the whole system in an optimal state, so as to achieve the maximum energy savings, becoming a research hotspot in the field of air conditioning control.In this paper, variable air volume(VAV, Variable-Air-Volume Air-condition System) air conditioning system will be as an example to study. The emergence of VAV air conditioning system is to reduce the energy consumption, compared with the conventional constant air volume air conditioning system, its air conditioning mode is more advanced, it is in the situation where the air supply temperature does not change and change the room air volume to achieve its working state, being able to achieve the indoor temperature setting value and to maintain the stability of the objective. Variable air volume air conditioning system can effectively reduce the total air volume and capacity, it not only can reduce energy consumption, but also reduce the investment of funds. The VAV terminal device which is pressure irrelevant is an important part of the variable air volume air conditioning system, due to its efficient means of regulation and greater energy saving potential, it has gradually become the research focus of people in recent years. Its main control object is the indoor temperature, the auxiliary control object is air volume, the two together constitute the cascade control loop.Due to the large hysteresis, changeable, time-varying are the most typical characteristics of VAV air conditioning system and at the same time, nonlinear is also a typical feature of the system, it is very difficult for the system to establish a precise mathematical model. For a general PID controller, it has simple algorithm, high reliability, but its parameter is not easy tuned, so the conventional PID control is difficult to meet a variety of control requirements in the VAV air conditioning system where mentioned in this paper, therefore, in addition to establish the mathematical model of the control system in this paper, and put forward a kind of particle swarm algorithm to optimize PID parameters of the control system, but the basic particle swarm algorithm has low precision, easy divergence, not convergence, lack of diversity and other shortcomings, so when we apply for it, it is necessary for us to improve and perfect it. In this paper,i introduced an improved algorithm for it, namely CPSO,i have established the mathematical model of the VAV terminal units and the simulation experiment was carried out on the basic particle swarm and chaotic particle swarm optimization PID,their experiment results were compared. The simulation results improved that the algorithm is effectiveness, and the external interference on the system of air flow and temperature can be controlled effectively with the help of the controller. |
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