In this paper, total harmonic distortion (THD) minimization of the output voltage of multilevel inverters is discussed. An efficient approach in reducing the harmonic contents of the inverter's output voltage is THD minimization. In multilevel inverters with a fundamental frequency switching strategy (each switch turning on and off once per output cycle), the switching angles can be selected so that the output THD is minimized (such as the so-called optimal-minimization-of-THD strategy). To obtain the optimum switching angles, an optimization algorithm is applied to the output-voltage THD. In three-phase multilevel inverters, the optimization algorithm is commonly applied to the phase voltage of the inverter. This results in the minimum THD in phase voltage but not necessarily in the line-to-line minimum THD, whereas in three-phase applications, the line-voltage harmonics are of the main concern from the load point of view. In this paper, using the genetic algorithm, a THD minimization process is directly applied to the line-to-line voltage of the inverter. This paper is based on a seven-level inverter. To verify the simulation results, a seven-levelcascaded-H-bridge-inverter-based hardware prototype, including an ATMEGA32 AVR microcontroller, has been implemented. Both simulation and experimental results indicate superiority of this approach over the commonly used phase-voltage THD minimization approach.Index Terms-Genetic algorithm (GA), line-voltage total harmonic distortion (THD), multilevel inverter, optimal minimization of THD (OMTHD), THD minimization.
Recently, Voltage Source Converter (VSC) basedHigh Voltage Direct Current (HVDC) transmission systems have gained more attention. In this paper, a control method for a modular VSC based HVDC transmission system with high frequency isolation referred to as high frequency isolated modular converter is proposed. In the high frequency isolated modular converter configuration, several floating DC capacitors in all three phases are connected in series, and voltage balancing control of these floating dc capacitors is required. In this paper, an appropriate control structure with the capacitor voltage balancing controller is proposed. The proposed control scheme consists of three layers to control terminal DC bus voltage and balance DC capacitor voltages of each building block. Detailed PSCAD simulation results are presented to evaluate the performance of high frequency isolated modular converter. Controller hardware-in-the-loop simulation of the high frequency isolated modular converter is also performed by Real Time Digital Simulator (RTDS), and RTDS results are presented to verify the control structure. Finally, lab-scale experimental results are presented to validate the proposed control method.
Index Terms-Voltage Source Converter (VSC), HVDC transmission systems, Capacitor Voltage Balancing Controller, High Frequency Isolated Modular Converter.0093-9994 (c) , respectively. His recent research interests are PV/battery power electronic systems, high frequency power converters and high bandwidth current sensing schemes.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.