Application of Model Reference Adaptive Control to Solar Thermal Utilization Systems

Abstract

A proportional plus integral plus derivative (PID) controller is used to obtain usable energy from the sun in almost all the solar systems in Japan. However, it is difficult to collect the heat continuously close to a prescribed temperature using a PID controller because the solar radiation is often interrupted by passing clouds. We investigated, therefore, a Model Reference Adaptive Control (MRAC) system. In order to demonstrate its effectiveness, we constructed a MRAC system and introduced it into the collector loop of a solar system. This paper gives an outline of the MRAC algorithm and describes the experimental results for the outlet fluid temperature response of the loop by the MRAC and PID. From these results, it is shown that the MRAC algorithm is suitable for controlling a system affected by irregular disturbances in the insolation.