Imbalance Mechanism and Balanced Control of Capacitor Voltage for a Hybrid Modular Multilevel Converter

Lu, Maozeng; Hu, Jiabing; Zeng, Rong; Li, Wuhua; Lin, Lei

doi:10.1109/tpel.2017.2743780

Cited by 68 publications

(34 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The third harmonic voltage injection scheme refers to superimposing the third harmonic zero-sequence component on the three-phase modulation waves [19] In equation (8), ucir is the second order voltage component generated by controlling the second order harmonic circulating current. ucir is usually ignored in the control system when analyzing the capacitor voltage fluctuations since its magnitude is small [21], [24], [26], [27]. To simplify the presentation, the second and third harmonic injection coefficients k2 and k3 are defined as (the subscripts 2 and 3 indicate the second and third harmonics):…”

Section: Mathematical Model Of Harmonic Injection In Hybrid Mmcsmentioning

confidence: 99%

“…During this period, only the FBSMs participate in the sorting algorithm. Therefore, FBSMs will be charged and discharged more frequently than HBSMs, arising from the difference in capacitor voltage fluctuations between the two types of SMs [26]- [27]. Simulations have shown that the energy accumulation of FBSMs during the above period is positively correlated with the range of the fluctuation difference.…”

Section: Suppression Effects Of the Voltage Fluctuation Differencmentioning

confidence: 99%

“…However, the classical scheme is designed with m=1.15, thus further optimization is limited by this specific operating condition. In addition, although different mechanisms of the capacitor voltage fluctuations in HBSMs and FBSMs of hybrid MMC are analyzed in [26], the suppression strategies are not discussed, which may have a large impact on the overall capacitor voltage fluctuations [27].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Dual Harmonic Injection for Reducing the Submodule Capacitor Voltage Ripples of Hybrid MMC

Weicheng

Gao

et al. 2021

IEEE J. Emerg. Sel. Topics Power Electron.

View full text Add to dashboard Cite

Reducing the capacitor voltage ripples of the half-bridge sub-modules (HBSM) and full-bridge sub-modules (FBSM) in a hybrid modular multilevel converter (MMC) is expected to reduce the capacitance, volume and costs. To address this issue, this paper proposes a dual harmonic injection method which injects the second harmonic circulating current and third order harmonic voltage into the conventional MMC control. Firstly, the mathematical model of the proposed control is established and analyzed. Then, the general strategy of determining the amplitude and phase angle of each injection component is proposed to suppress the fluctuations of the fundamental and double frequency instantaneous power. The proposed strategy can achieve the optimal power fluctuation suppression under various operating conditions, which also has the advantage of reducing the voltage fluctuation difference between HB and FB SMs. The correctness and effectiveness of the proposed strategy are verified in simulations in PSCAD/EMTDC. Index Terms-Hybrid modular multilevel converter (MMC); second harmonic circulating current; third harmonic voltage; dual harmonic injection; fluctuation suppression. NOMENCLATURE Symbols: Descriptions Udc Pole-to-pole dc voltage. Uac Amplitude of the AC-side phase voltage. Im Amplitude of the AC-side phase current. ω Fundamental angular frequency.

show abstract

Section: Mathematical Model Of Harmonic Injection In Hybrid Mmcsmentioning

confidence: 99%

Section: Suppression Effects Of the Voltage Fluctuation Differencmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Dual Harmonic Injection for Reducing the Submodule Capacitor Voltage Ripples of Hybrid MMC

Weicheng

Gao

et al. 2021

IEEE J. Emerg. Sel. Topics Power Electron.

View full text Add to dashboard Cite

show abstract

“…Besides, converters adopt HBSM occupy fewer hardware resources in the control system. SMs of many other structures have also been proposed according to different application requirements such as high efficiency, dc-fault current blocking, and smaller capacitor voltage ripple [7], [8].…”

Section: Introductionmentioning

confidence: 99%

A Novel Advanced Traction Power Supply System Based on Modular Multilevel Converter

Peng

Han

et al. 2019

IEEE Access

View full text Add to dashboard Cite

Due to the attractive advantages such as modularity, scalability and excellent power quality of modular multilevel converter (MMC), converters based on MMC could be a promising alternative solution for traction transformer. A novel MMC-based advanced co-phase traction power supply system is proposed in this paper to solve power quality issues and eliminate the neutral sections in the traditional traction power supply system. And in the proposed system, a DC power transmission system is designed, which provides convenient access for distributed energies benefiting the utilization of the natural resources such as solar energy and wind energy along railways. In order to ensure the normal operation of the proposed system, nearest-level modulation considering voltage balancing is designed for MMCs. The mathematic model three-phase MMC-based rectifier is derived in detail. Based on the mathematic model, dual current-loop control is designed for the rectifier. Besides, the parallel operating traction substations suffer circulating current issue. A droop control combining with double closed-loop control is designed to deal with the problem. The correctness and feasibility of the system and its modulation and control strategies is verified through simulation and a small-scale experiment. INDEX TERMS Electrified railway, traction power supply system, modular multilevel converter (MMC), three-phase rectifier, single-phase inverter.

show abstract

“…This in turn leads to unequal voltage stress across the switching devices, making the use of MLIs unproductive. So the dc-link capacitor voltages and grid current need to be controlled independently [11,[14][15][16][17][18][19][20].…”

Section: Introductionmentioning

confidence: 99%

Single‐phase cascaded multilevel inverter topology addressed with the problem of unequal photovoltaic power distribution in isolated dc links

Sharma

Nakka

2019

IET Power Electronics

View full text Add to dashboard Cite

This study presents a control scheme for a grid-connected cascaded H-bridge multilevel inverter (CHBMLI) based solar energy conversion system (SECS) addressing the problem of distinct temperature and irradiations which raise to partial shading and panel mismatch conditions in large-scale photovoltaic (PV) generation. Along with feasibility in high-voltage system, the major advantage of isolated dc links in CHBMLI suffers the distinct dc-link voltage conditions when employed as a pulse-width modulated (PWM) converter governing either unequal dc loads or dc sources due to variable power consumption or generation, respectively. The proposed control scheme has the ability of balancing the dc-link capacitors in each H-bridge cell of CHBMLI adopted for this system and during the above-said power generation mismatch conditions in SECS. The proposed system along with maximum and efficient energy conversion, the power quality in the grid-side voltage and injected currents is also monitored and maintained as per standards. In addition, the modelling analysis of the converter has also been derived to define the mathematical model of CHBMLI as PWM converter adopted for this application. The performance of system has been analysed using MATLAB simulation and validated experimentally on prototype model by using dSPACE-1104.

show abstract

Imbalance Mechanism and Balanced Control of Capacitor Voltage for a Hybrid Modular Multilevel Converter

Cited by 68 publications

References 21 publications

Dual Harmonic Injection for Reducing the Submodule Capacitor Voltage Ripples of Hybrid MMC

Dual Harmonic Injection for Reducing the Submodule Capacitor Voltage Ripples of Hybrid MMC

A Novel Advanced Traction Power Supply System Based on Modular Multilevel Converter

Single‐phase cascaded multilevel inverter topology addressed with the problem of unequal photovoltaic power distribution in isolated dc links

Contact Info

Product

Resources

About