Design and Implementation of Adaptive Neuro–Fuzzy Inference System Based Control Algorithm for Distribution Static Compensator

Abstract

This article focuses on the design and implementation of a distribution static compensator using an adaptive neuro–fuzzy inference system based controller. The distribution static compensator is controlled to provide power quality improvement, such as power factor correction, harmonics compensation, load balancing, and voltage regulation. Active and reactive power fundamental components of load currents are extracted using d-q theory. A distribution static compensator is realized using a voltage source converter. Both simulation and experimental results prove the effectiveness of the control algorithm under non-linear loads. The adaptive neuro–fuzzy inference system based controller works satisfactorily for power factor correction and harmonics reduction under balanced as well as unbalanced load conditions. Test results clearly depict the dynamics of the performance of the system under steady state as well as dynamics under load change and load unbalancing.

Keywords:

• adaptive neuro–fuzzy inference system
• power factor correction
• harmonics compensation
• voltage source converter
• voltage regulation
• power quality

Appendix A

1. Simulation parameters—AC supply source: 3 phases, 110 V (L-L), 50 Hz; source impedance: Rs = 0.4 Ω, Ls = 1 mH; non-linear load: three-phase full-bridge uncontrolled rectifier with R = 12 Ω, L = 100 mH; reference DC-link voltage: 200 V; interfacing inductor: L = 3.4 mH; ripple filter: R_f = 5 Ω, C_f = 10 μF.

2. Experimental parameters—AC supply source: 3 phases, 110 V (L-L), 50 Hz; non-linear load: three-phase full-bridge uncontrolled rectifier with R = 18–120 Ω, L = 100 mH; DC-link capacitor value: C = 1640 μF; reference DC-link voltage: V_dc = 200 V; interfacing inductor: L = 3.4 mH.

Appendix B

The selection of interfacing inductor (L_f) for VSC depends on ripple current Δi and switching frequency f_s. The value of L_f is given as (B1) where the DC-link voltage is v_dc = 200 V, modulation index is m = 0.8, overload factor is a = 1.2, switching frequency is f_s = 5 kHz, and ripple current is Δi, which is 5% of rated VSC current. From the above given values, the value of interfacing inductor calculated is approximately 3.4 mH.

The rating of interfacing inductor designed here is 3.4 mH with a 10-A RMS current. The equation for calculating the number of turns of the inductor is given as (B2) where L is the inductance (in Henrys), I_m is the peak value of rated inductor current (in A), A_c is the core cross-sectional area (in cm²), and B_m is the flux density (in Tesla). The value of N obtained from Eq. (B1)(30) is 50. The gauge of wire is given by (B3) where I is rated inductor RMS current (in amps), and J is the current density (in amp./mm²); the calculated value of gauge a is 3.33 mm². Air-gap length (l_g) is given as (B4) where L is inductance (in Henrys), N is the number of turns, A_c is the core cross-sectional area (in cm²), and μ₀ = 4π * 10⁻⁷ H/m; the calculated air gap value is 0.93 mm.

Additional information

Notes on contributors

Manoj Badoni

Manoj Badoni received his bachelor's degree in technology in instrumentation engineering from University Science and Instrumentation Centre, Srinagar Garhwal, Uttrakhand, in 2006 and his master's degree in electronics engineering from Punjab Engineering College, Chandigarh, India, in 2008. He is currently working toward his Ph.D. in the Electrical Engineering Department of Delhi Technological University, Delhi, India. His areas of research interest include power electronics, power quality, and distributed generation.

Alka Singh

Alka Singh received her bachelor's degree in electrical engineering from Delhi College of Engineering, Delhi, India, in 1996; her master's degree in technology in power systems from the Indian Institute of Technology (IIT), New Delhi, India, in 2001; and her Ph.D. from Netaji Subash Institute of Technology (Delhi University), Delhi, India, in 2006. She is currently working as an associate professor in the Department of Electrical Engineering, Delhi Technological University, Delhi and has over 15 years of teaching and industrial experience. She is an IEEE member and a life member of the Indian Society for Technical Education. Her research interests include flexible AC transmission systems (FACTS), power systems, and power quality.

Bhim Singh

Bhim Singh received his bachelor's degree in electrical engineering from University of Roorkee, Roorkee, India, in 1977 and his M.Tech. and Ph.D. from the IIT Delhi, New Delhi, India, in 1979 and 1983, respectively. In 1983, he joined the Department of Electrical Engineering, University of Roorkee, as a lecturer; he became a reader there in 1988. In December 1990, he joined the Department of Electrical Engineering, IIT Delhi, as an assistant professor, where he became an associate professor in 1994 and a professor in 1997. He has guided 54 Ph.D. dissertations and 150 M.E./M.Tech. theses. He has been granted 1 U.S. patent and filed 15 Indian patents. He has executed more than 70 sponsored and consultancy projects. He is a fellow of the Indian National Academy of Engineering, the National Science Academy, the Indian Academy of Science, the Institute of Engineering and Technology (UK), the Institution of Engineers (India), the World Academy of Sciences (FTWAS), the Indian National Science Academy, and the Institution of Electronics and Telecommunication Engineers. His fields of research interest include power electronics, electrical machines, electric drives, power quality, flexible AC transmission systems, high-voltage direct-current transmission systems, and renewable energy generation.