Frequency Domain Design of Controllers for Lighting Process

Frequency Domain Design of Controllers for Lighting Process

Table of Contents


The lighting process is one of the biggest power consumption process that have place in every building, from the total energy consumption of a building 25% to 40% being allocated to the lighting process. Nowadays intelligent smart light bulbs based on the LED technology and having internet connection are present on the market improving the power consumption of a household. This paper proposes the frequency domain design of different types of controllers used for maintaining the light level from a room that is illuminated with smart light bulbs to a desired level, improving the comfort and reducing the power consumption by maintaining the light intensity to the desired level. The first-order plus time delay and second-order plus time delay mathematical models are used in the controllers design for lighting process. A comparison of digital simulation results is included.


The evolution of the light bulb started with the beginning of the 19th century when the incandescent light bulb was discovered. The efficiency of the incandescent light bulb was initially around 2-22 lm/W, but nowadays with the Light Emitting Diode (LED) technology used into the latest generation of the light bulbs optimizes the power consumption and generates between 70 and 100 lm/W [1]. Even with the latest generation of the LED light bulbs in industrial buildings more than 25% of the power consumption costs is generated by the lighting process [2], [3]. This happens because the majority of the buildings make use of control of lighting process by on-off (relay type) control algorithms.

The idea of an intelligent lighting system platform based on smart light bulbs is presented in [4]. The platform described in [4] is based on sensors and smart LED bulbs which are controlled by a central service for optimizing the power consumption. The benefits of this platform are: reducing the power consumption of a household by using the natural day light as much as possible, improving the light comfort and relatively easy implementation in every house because it does not require changes of the existing power supply infrastructure. Two types of mathematical models were also identified in [4] for the intelligent smart bulbs used by the platform: first-order plus time delay model (FOPTD) and second-order plus time delay (SOPTD) model.

The main contribution of this paper is represented by the design of Integral (I) and Proportional-Integral (PI) controllers used by the platform presented in [4] to maintain the light intensity level to a desired value. For designing the controllers, the FOPTD and SOPTD mathematical models of he smart light bulbs identified in [4] are used. The frequency domain design is used to tune the controllers. This paper is structured as follows: Section II presents some similar achievements related to the control of lighting systems. Section III describes the FOPTD and SOPTD mathematical models of the smart light bulb used by the intelligent lighting platform. Section IV designs the controllers and analyzes the performance of the lighting control systems. Section V presents the conclusions and discusses the future work and different control strategies.


This paper presented the design and tuning of two types of controllers used for maintaining the light intensity level from a room to a desired value. This is important as will improve the comfort. The lighting process was described by two types of mathematical models, FOPTD and SOPTD. For the FOPTD mathematical model of the process, two types of controllers were tested: an I controller and a PI controller, the PI controller providing better responses to external disturbances. For the SOPTD model a PI controller was used providing much better settling time than the same controller for the FOPTD process. The comparison presented in Sub-section IV.D is not fully fair as the controller tuning depends on some parameters that are chosen by the designer. A fair comparison would be to impose additional performance specifications expressed by optimization problems and carry out the optimal tuning of all controller parameters. The objective functions should be chosen in several versions and reducing the power consumption can be inserted in this regard. Several classical and modern optimization algorithms can be used to solve the optimization problems [16]−[23]. Further work will be focused on testing the I and PI controllers on the real process, which was not available at the time of submitting this version of the paper because of some software issues caused by malicious software upgrade of the system. Future work will also be focused on developing other nonlinear controllers [24]−[27] including classical [28]−[30] and modern [31]−[34] fuzzy ones.

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FULL Paper PDF file:

Frequency Domain Design of Controllers for Lighting Process



A. Borlea, R. Precup, I. Borlea, and A. N. Dragus,




IoT-Based Energy Efficiency in smart HomesbySmartLighting Solutions

Publish in

2020 IEEE 14th International Symposium on Applied Computational Intelligence and Informatics (SACI), Timisoara, Romania, 2020, pp. 000053-000058,



PDF reference and original file: Click here

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Somayeh Nosrati was born in 1982 in Tehran. She holds a Master's degree in artificial intelligence from Khatam University of Tehran.

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Professor Siavosh Kaviani was born in 1961 in Tehran. He had a professorship. He holds a Ph.D. in Software Engineering from the QL University of Software Development Methodology and an honorary Ph.D. from the University of Chelsea.

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Nasim Gazerani was born in 1983 in Arak. She holds a Master's degree in Software Engineering from UM University of Malaysia.