Linear Thermal Power Controller Design and Implementation for Efficient Electric Heating

A prototype enclosure that is built for space heating was equipped with a resistive heater element and two temperature sensors. During a one-hour temperature regulation experiment, a Bang-Bang controller like those commonly used for residential heating control was used and the results were compared to a novel linear controller developed for the same purpose. The variables of comparison include temperatures and electrical power data. The study focuses on the linearization of the control system using a power electronics converter. The input of the converter must have linear relationship with the output power provided to the thermal system. Linearization was achieved by identifying a mathematical relationship that eliminates quadratic power function as well as converter's nonlinearity. This relationship was further implemented in the microcontroller. A second order linear mathematical model was later developed to identify and estimate the thermal circuit parameters utilizing a one-hour test facilitated through this new controller. Comparative results between simulation and experimental work validated the linearity of power control. Temperature disparity and input power characteristics were also improved using this new converter for controlling the space heater. The system developed is an important step toward energy savings, temperature improvements and demand side management for reducing peak demand.