Analysis on Displacement Angle of Phase-Shifted Carrier PWM for Modular Multilevel Converter

Abstract

This paper provides theoretical and experimental discussions on the characteristics of the modular multilevel converter (MMC) when phase-shifted carrier sinusoidal pulse-width modulation (PSC-SPWM) is applied. Harmonic-cancellation characteristics of output voltage and circulating current are analyzed on the basis of a general implementation of PSC-SPWM with two freedom displacement angles. Five available PSC-SPWM schemes with different carrier displacement angles were obtained, and a detailed performance comparison about output voltage and circulating current harmonic characteristics is presented. On the basis of the equivalent circuit with ideal transformer representation of the SMs, capacitor voltages affected by PSC-SPWM schemes are also briefly analyzed. The proposed PSC-SPWM schemes can unify two different cases of odd and even SM situations for output voltage and circulating current harmonic minimization, respectively. Lastly, the optimal schemes for practical MMC application were verified by simulation and experiments on an MMC prototype.

Design, Control and Testing of a Modular Multilevel Converter with a Single Cell per Arm in Grid-Forming and Grid-Following Operations for Scaled-Down Experimental Platforms

“…In addition, it can have the same outer controls as shown in Section 4.4. The control that cannot be applied is the NLM, which also cannot be applied in the other converters presented in the literature [3,[5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20].…”

“…When the number of cells is sufficiently high (which is the case for highvoltage applications, due to the high number of cells required) the preferred modulation technique is nearest level modulation (NLM), which basically modulates voltages in a "staircase" approach, dramatically reducing the switching frequency and the associated losses. For research and testing purposes, several research projects have developed scaled MMC experimental platforms at low-or medium-voltage levels, where the number of cells per arm is significantly reduced [3,[5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. While some of the converters' cells can be operated using an NLM technique, in order to obtain acceptable power quality, some of the cells need to be operated with pulse width modulation (PWM).…”

A Powerful Tool for Optimal Control of Energy Systems in Sustainable Buildings: Distortion Power Bivector

“…These harmful and costly effects of harmonics have been discussed extensively and spurred stringent requirements by international institutions regarding the allowed levels of harmonics at the point of connection to the power supply [15], (IEEE Recommended Practice and Requirements for Harmonic Control in Electric Power Systems). On the other hand, as is well known, a phase displacement between corresponding voltages and currents [16] indicates both a low utilization of the generation and distribution equipment and increased line losses for the same power consumption level.…”

Harmonic Mitigation Using Meta-Heuristic Optimization for Shunt Adaptive Power Filters: A Review

“…In this study, the focus is on understanding meta-heuristic algorithm methods and AI engineering models, combining the above models to improve power loss compensation through a shunt adaptive power filter (Figure 2). Combining AI engineering modeling with meta-heuristic algorithm models improves the model's prediction accuracy and improves the model's convergence speed [23]. Along with today's trend, the amount of electricity is increasing, specifically in addition to the fact that countries around the world want to gradually reduce their dependence on energy and gas sources, improve the use of renewable energy sources and save electric energy, reduce power loss caused by harmonics by applying [1] meta-heuristic algorithm techniques and technical models.…”