PV Charging Station with VSS-IMSAF and SOSMCC Disturbance Observer Based Controls to Enhance the Distribution Grid Capability

Abstract

This paper present a three-phase grid-tied (GT) charging station (CS) based on photovoltaic (PV) arrays. The purpose of the proposed CS is to support the distribution grid under heavy electric vehicles (EVs) loads with improved power quality. The variable step size improved multiband adaptive structured filter (VSS-IMSAF) technique is used to control voltage source converter (VSC). Due to the variable step size, the control regulates the grid currents and subjects to the proper step size selection to improve the performance of CS. Moreover, the charge/discharge operations of the electric vehicle battery (EVB) are also incorporated. For regulation of the DC bus voltage, second-order sliding mode cascaded control (SOSMCC) is used, which also controls the charge/discharge operations. The SOSMCC is equipped with the linear observer (LINO), second-order sliding mode observer (SOSMO), linear extended state observer (LESO), and nonlinear extended state observer (NESO), which reduce the overshoot, undershoot, and uncertainties in the voltage at DC link and EV battery current quickly and accurately. This charging station is also capable to operate under load unbalancing, unavailability and reduced insolation, and sudden change of the mode of operation (charging/discharging). The presented controls improve the performance of the CS and feed the reduced harmonic current to the grid under nonlinear load. The test results are presented using the OPAL-RT real-time simulator under various scenarios.

KEYWORDS:

• Variable Step Size
• Linear extended disturbance observer
• Second-order sliding mode control
• Grid-tied
• Digital storage oscilloscope (DSO)

ACKNOWLEDGEMENTS

The government of India and the state of MP (MPCST) are to be thanked for funding this project as part of the startup research grant (SRG/2020/001742).

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Notes on contributors

Dulichand Jaraniya

Dulichand Jaraniya was born in Mandsaur, India, in 1994. He received the BTech degree in electrical engineering and the MTech degree in electrical drives from Maulana Azad National Institute of Technology, Bhopal, India, in 2016 and 2019, where currently he is working towards a PhD degree in the electrical engineering department. His research interests include electric vehicle charging stations, power electronics, power quality, and renewable energy.

Shailendra Kumar

Shailendra Kumar (M”15, SM”20) was born in Mahoba, (UP) India, in 1988. He received BTech degree in electrical and electronics engineering from Uttar Pradesh Technical University, Lucknow, India, in 2010, and the MTech degree in power electronics, electrical machine and drives (PEEMD) from the Indian Institute of Technology, Delhi, India, in 2015. He has completed his PhD degree in Department of Electrical Engineering from the Indian Institute of Technology Delhi, New Delhi, India on May, 2019. Currently, he is working as an assistant professor at Maulana Azad National Institute of Technology, Bhopal. His research interests include power quality, grid integration, custom power devices, microgrid and renewable energy. Dr Kumar is recipient of prestigious POSOCO power system award (in Master as well as in Doctoral categories) in 2016 and 2019. He is also a recipient of Professor Som Nath Mahendra Student Travel Awards for the IEEE PEDES 2018 conference and the IEEE UPCON Best Paper Award in 2016 and 2018. Email: [email protected]