Publication Date


Document Type


Committee Members

Kuldip Rattan (Advisor)

Degree Name

Master of Science in Engineering (MSEgr)


Proper amount of light in a business office is important for health and productivity of the employees. On a sunny day, there may be more than enough light entering the office from outside to carry out the necessary tasks. Presently, the main source of light in most offices is the fluorescent lamp. Thus, It is possible to save energy by dimming the fluorescent lamp. Dimming of the fluorescent lamp is possible by changing the frequency of the sinusoidal voltage or current. Hence, there is a need of a control system to adjust the light from the fixtures based on the light entering the office from outside. The design of a light control system is possible if the simulation of fluorescent lamp, the electronic ballast and the light sensor is available. Presently, the number of light fixtures in a commercial office is based entirely on the activities performed in that office. No attention is paid to the outside light entering the office from windows. In this thesis, a fuzzy logic controller to dim the fluorescent lamp based on the availability of the outside light is presented. To carry out the design of a fuzzy controller, a Matlab-Simulink model based on the simulation of the complete light system is developed. The light system consists of an electronic ballast and a fluorescent lamp. The outside light is obtained from a light sensor installed on the frame of the window. The fuzzy controller has two inputs: one is the output of the light sensor and the other is a reference frequency equivalent to maximum light level of the fluorescent lamp. The controller output controls the frequency of the electronic ballast. The rule-base of the fuzzy logic controller is developed based on the operation of the electronic ballast, the fluorescent lamp and the light sensor. Simulation was carried out with equally spaced five and seven fuzzy sets for the input and output. The fuzzy sets were then tweaked to take advantage of the piecewise linear control surface provided by the fuzzy logic controller. The simulation results show that dimming the fluorescent lamp can result in a substantial amount of energy saving and thus reduced the cost of utilities.

Page Count


Department or Program

Department of Electrical Engineering

Year Degree Awarded