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

Energies ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 6743
Author(s):  
Qian Cheng ◽  
Chenchen Wang ◽  
Jian Wang
Keyword(s):  
Output Voltage ◽  
Pulse Width Modulation ◽  
Performance Comparison ◽  
Modular Multilevel Converter ◽  
Multilevel Converter ◽  
Current Harmonic ◽  
Circulating Current ◽  
Displacement Angle ◽  
Harmonic Cancellation ◽  
Sinusoidal Pulse Width Modulation

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.

scholarly journals Research of modular multilevel converter with phase-shifted pulse-width modulation

2021 ◽  
Vol 280 ◽  
pp. 05009
Author(s):  
Ihor Kozakevych ◽  
Roman Siyanko
Keyword(s):  
Mathematical Model ◽  
Pulse Width ◽  
Output Voltage ◽  
Pulse Width Modulation ◽  
Electric Energy ◽  
Point Of View ◽  
Modular Multilevel Converter ◽  
Multilevel Converter ◽  
Energy Converter ◽  
Circulating Current

The work is devoted to the study of performance of a multilevel electric energy converter using phase-shifted pulse-width modulation. Equations describing the state of a dynamic system multilevel converter - load are investigated and a mathematical model of the system in Matlab / Simulink environment has been constructed. Variants of implementation of phase-shifted pulse-width modulation systems from the point of view of influence on harmonics of output voltage and magnitude of circulating current in the converter are investigated.

scholarly journals Circulating Current Suppression Control in Surrogate Network of MMC- HVDC System

2020 ◽  
Vol 8 (6S) ◽  
pp. 29-34
Keyword(s):  
Output Voltage ◽  
Electromagnetic Transients ◽  
Modular Multilevel Converter ◽  
Multilevel Converter ◽  
Voltage Balancing ◽  
Hvdc System ◽  
Circulating Current ◽  
Capacitor Voltage ◽  
Circulating Currents ◽  
Three Phases

Modular multilevel converter consists of hundreds of submodules (SMs) like half bridge and full bridge converters etc. These hundreds of SMs and electrical nodes poses challenges while computing electromagnetic transients (EMTs). This problem becomes more complex while computed in real-time. To overcome this, an equivalent topology to model MMC arm/valve called surrogate network is utilized. But, the major ambiguity integrated with surrogate network model is SM capacitor voltage balancing. This leads to variation in voltage among the three phases which are parallel and produces circulating current between the three phases. A control circuitry is proposed in this paper to suppress/minimize circulating currents between the phases. Apart from circulating current suppression, the ‘ac’ output voltage is also enhanced at the converter with this proposed controller. Simulation is carried out in RSCAD software using RTDS simulator.

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