A fractional order PID controller using MACOA for indoor temperature in air-conditioning room

Abstract

Aiming at controlling indoor temperature of each air-conditioning room equipped with fan coil unit (FCU), this paper proposes a hybrid control system to deal with such problem, in which a fractional order PID controller for indoor temperature (IT-FOPIDC) and a three-position controller for supply air volume (SAV-TPC) are used to maintain steady indoor temperature, respectively. For the key problem of tuning parameters of IT-FOPIDC, a modified ant colony optimization algorithm (MACOA) is reconstructed, and it is tested to be feasible by the simulation results. Thus, an algorithm using this MACOA is designed to adaptively solve the satisfied values of five parameters of IT-FOPIDC to further upgrade the control quality of indoor temperature from software. In the meanwhile, SAV-TPC manipulates the corresponding flow rate of supply air discharged from FCU to provide the dynamic variation of cooling or heating load to an air-conditioning room. So these two controllers work together for achieving the desired indoor temperature. The corresponding numerical simulation of this hybrid control system is carried out and the results indicate that this algorithm using MACOA is reliable to tackle the key problem of tuning parameters of IT-FOPIDC so that the control quality of indoor temperature is obviously improved. Moreover, for the same IT-FOPIDC, the control performance of the other intelligent optimization algorithms is compared to that of the proposed algorithm using MACOA under the same scenario, simulation results also show the latter is superior to the former in terms of analyzing the dynamic responses of indoor temperature, which may offer the corresponding reference guides for regulating the key performance parameters in HVAC& R engineering.