abstract

• This paper presents a current controller for the single-phase grid-connected modular multilevel converter of 2n%2b1 levels. The controller is designed based on the mathematical model of the converter. It has the aim of injecting an almost pure sinusoidal current with a proper phase, despite the low-frequency harmonics present on the grid voltage. Also, a loop for the circulating current is developed to keep this variable close to a constant value for proper internal operation of the converter. The overall current controller comprises injected and circulating current loops. Out of these loops, a voltage reference for each converter arm is built, which is then used in a phase-shift carrier-based pulse-width modulation to generate the switching sequences. These are then used to command the modules conforming the converter. Experimental results in a 7-level modular multilevel converter (n=3) operating under harmonic distortion in the grid voltage are obtained from a hardware-in-the-loop test bench to validate the performance of the proposed current controller. Copyright © 2018 John Wiley %26 Sons, Ltd.

authors

• Catzin-Contreras G.A.
• Escobar G.
• Lopez-Sanchez M.J.
• Valdéz Fernández Andrés Alejandro

publication date

• 2018-01-01

published in

• International Transactions on Electrical Energy Systems  Journal

keywords

• grid voltage harmonic distortion; modular multilevel converter; phase-shift carrier-based pulse-width modulation Controllers; Electric current control; Harmonic analysis; Harmonic distortion; Modulation; Pulse width modulation; Voltage control; Circulating current; Current controller; Distorted grid voltage; Grid voltage; Hardware-in-the-loop tests; Internal operations; Modular multilevel converters; Sinusoidal currents; Power converters

Digital Object Identifier (DOI)

• 10.1002/etep.2524

start page

end page

volume

• 28

issue

• 4