Mathematical Modeling of Phase-Controlled Converters Considering Discontinuous Conduction Modes

Abstract

Despite possessing outstanding features, phase-controlled converters are also known for their control performance deterioration whenever their output currents become discontinuous. This paper aims to provide a mathematical framework to overcome converter input/output characteristic nonlinearities, arising from discontinuous current conduction regime. A secondary purpose is to expand the idea of Predictive Current Control (PCC) for phase-controlled converters, taking into account multiple discontinuous current conduction modes. To this end, starting with a detailed converter circuit analysis, equations describing boundaries between converter operating modes are derived and depicted as a graph. The resulted graph is utilized to devise an algorithm to identify mode of operation and to calculate firing angle corresponding to “desired average output voltage”. Experiments in conjunction with simulation studies are conducted to evaluate the assumptions made, the equations derived, and the algorithm devised. Based on the proposed algorithm, two improvements on converter current control are achieved. Firstly; the transfer characteristic of the converter is linearized. Secondly; the PCC strategy, which has attracted much attention recently, is implemented in Single Phase Full Controlled (SPFC) converter. Moreover, the comprehensive treatment of all operating mode boundaries presented in this paper helps deepen physical insight into the SPFC converter operation.

Keywords::

• mathematical modeling
• phase-controlled converters
• discontinuous conduction mode
• predictive control
• linearization technique
• fast current control
• Thyristor

ABBREVIATIONS

SPFC	=	Single Phase Full Controlled
DCM	=	Discontinuous Conduction Mode
CCM	=	Continuous Conduction Mode
CEMF	=	Counter-Electromotive Force
ICT	=	Inverse Cosine Technique
PCC	=	Predictive Current Control
IMA	=	Inverse Mapping Algorithm
RLe	=	Resistive-Inductive DC Load

Additional information

Notes on contributors

Armin Afsharian Zadeh

Armin Afsharian Zadeh received his B.S. degree in control engineering from Jundi-Shapur University of Technology, Dezful, Iran, in 2011 and his M.Sc. degree in automation and instrumentation engineering from Shiraz University, Shiraz, Iran, in 2014. He has been with the electrical engineering Department of Jundi-Shapur University of technology since 2013. In addition, he has served as reviewer for different journals. His research interests include nonlinear control, optimization, and implementation of advanced control techniques to power electronics converters.

Faramarz Samani

Faramarz Samani received his B.S. degree and M.Sc. degree with honor, both in Electrical Engineering from Amirkabir University of Technology, Tehran, Iran, in 1993 and 1996, respectively. From 1996 to 2006 he served as a lecturer at the Department of Electrical Engineering in Azad University of Dezful, Iran. Then he joined Department of Electrical and Computer Engineering of Jundi-Shapur University of Technology, Dezful, Iran. He is currently pursuing his PhD degree in the Department of Electrical Engineering in Amirkabir University of Technology. From 2000 to 2011 he worked for FARAB Co., the largest constructor of hydropower plants in Iran, as senior electrical engineer, and after that he has served as a consultant in the same company. His research interest includes modeling, simulation, and fault diagnosis of electrical machines.

Behrooz Vahidi

Behrooz Vahidi received his B.S. degree in electrical engineering from Sharif University of Technology, Tehran, Iran, in 1980, his M.S. degree in electrical engineering from Amirkabir University of Technology, Tehran, in 1989, and his Ph.D. degree in electrical engineering from the University of Manchester Institute of Science and Technology, Manchester, U.K., in 1997. From 1989 to the present, he has been with the Department of Electrical Engineering in Amirkabir University of Technology, where he is now a professor. He has authored and coauthored more than 400 papers and six books on high-voltage engineering and power system. Prof. Vahidi is IEEE senior member and he is selected by the ministry of higher education of Iran and by IAEEE (Iranian Association of Electrical and Electronics Engineers) as the distinguished researcher of Iran. His main fields of research are high voltage, electrical insulation, power system transient, lightning protection, and pulse power technology.

Jafar Milimonfared

Jafar Milimonfared received his BSc degree in Electrical Engineering from Amirkabir University of Technology, and both his MSc and PhD degrees from Paris VI University, Paris, France, in 1981 and 1984, respectively. He joined Amirkabir University of Technology as an assistant professor in 1984, where he is now a professor of Electrical Engineering. His research interests include electrical machines design and analysis, power electronic, and variable speed drives.