In the present scenario, modular multilevel converters (MMCs) are considered to be one of most promising and effective topologies in family high-power because their design good scalability; MMCs extensively used high-voltage applications. Based on unique advantages, have attracted increasing attention from academic circles over past years. Several studies focused different aspects MMCs, including submodule topologies, modeling schemes, modulation strategies, control schemes for voltage...

The modular multilevel converter (MMC) is one of the most appropriate topologies for high-power applications due to its high modularity and low harmonic distortion. As faulty submodules (SMs) are bypassed, capacitor voltage switching frequency healthy SMs in arm will rise, which causes unbalanced power loss distribution among arms MMCs affects reliability MMCs. This article proposes a variable sampling frequency-based balancing control (VSF-PLBC), can balance through adjusting an inserted SM...

The modular multilevel converter (MMC) is attractive for medium-voltage and high-power applications because of the advantages its high modularity, availability, power quality. Due to unbalanced grid voltages, arm current among three phases MMC would unbalance, which cause temperature distribution MMCs affect reliability MMCs. This article proposes a variable frequency (VF) control strategy, can effectively realize balanced through adjusting carrier in each phase regulating device's switching...

The active circulating current suppression may cause high-frequency ripple in the dc link of modular multilevel converters (MMCs). In this article, a phase-shifted double-group multicarrier-based phase-disposition pulsewidth modulation strategy is proposed to eliminate dc-link MMCs, where fundamental frequency component and second-order arm reference are modulated, respectively, by two groups carriers. By shifting phase angles multicarrier each carrier period, injected into MMCs can be...

Thermal management is one of the most significant challenges for reliability improvement modular multilevel converters (MMCs). The thermal stress difference caused by uneven loss distribution between top and bottom IGBTs/diodes will lead to lifetime which decrease MMC. In this paper, a optimization strategy MMCs proposed, where maximum in IGBT/diode each SM can be effectively reduced through injecting optimum second-order harmonic current into circulating MMCs, accordingly improved proposed...

To address the problem of low fault diagnosis accuracy, this article proposes a multi-sensor information fusion-based open circuit (OC) method for three-phase voltage source inverters. First, current signals were simulated and collected under healthy condition, single switch OC, double OC faults. The data was parallel concatenated after simple preprocessing to complete data-level fusion. Then, one-dimensional convolutional neural network with large kernel (1D-LKCNN) used feature extraction...

Modular multilevel converters (MMCs) are widely applied to medium and high voltage occasions. The total power consumption of the submodule (SM) maximum devices in SM related operating costs lifetime MMC. Existing literature only considers loss optimization or maximal MMC’s SM. In this article, a reduced extended optimum control (RLEL-PLOC) is introduced inject first-best second harmonic circulation into arm current. Compared with conventional control, proposed could decrease semiconductor...

Fault localization is one of the most important issues for MMC consisting large number switches. This paper proposes a statistical multi-faults strategy MMC, where feature extraction algorithm capacitor voltage variations proposed to extract features based on exponential smoothing relationship among voltages. Based extracted features, faults in can be easily located with Grubbs Criterion according Table. The Criterion-based fault construct concise simple samples containing all global...

The modular multilevel converter (MMC) gradually turns into one of the most appropriate topologies for high power applications due to its modularity and low harmonic distortion. As submodule (SM) fails, SM capacitor voltage average value in faulty arm will rise, which would cause unbalanced losses distribution among six arms MMC affects reliability MMC. This paper proposed a variable phase-disposition pulsewidth modulation (PD-PWM) frequency control method, can effectively realize balanced...

The modular multilevel converter (MMC) becomes one type prospective converters for high voltage and high-power applications because of its modularity low harmonic distortion step by step. Gird imbalance will lead to arm current imbalance, resulting in power loss among three phases, which reduce the lifetime MMC. In this manuscript, a variable capacitor threshold value control (VCVTV) is proposed. case grid changing each phase, switching generated devices phase MMC can be changed, balance...

Modular multilevel converter (MMC) commonly uses modulation strategies such as phase shifted carrier pulse width (PSC-PWM) and nearest level (NLM). Compared with NLM, the output power quality of MMC PSC-PWM is better. PSC-PWM, switching loss junction temperature devices NLM strategy are lower. Combining advantages strategies, this paper proposes a hybrid strategy, according to probability distribution wind speed in farm, active thermal control realized by appropriate which effectively...

When it concerns the reliable working of modular multilevel converter (MMC), power loss balance control cannot be ignored. Under submodule (SM) malfunction condition, each arm MMC operates in an asymmetrical status, resulting unbalanced every MMCs, which affects operation's reliability. This essay proposes a variable capacitor voltage deviation predefined value-based (VCVDPV-PLBC), could optimize faulty arms' losses by regulating value to change devices' switching MMCs under SM malfunction....

The main challenge of the medium-voltage drive with modular multilevel converters (MMCs) is capacitor voltage ripple, and existing suppression method inevitably injects high-frequency common-mode circulating current into MMCs. However, errors occur increase frequency lead to failure injection methods. This paper proposes an improved method, which can suppress ripple under through compensating reference. proposed reduce peak value arm regulate compensation parameter automatically. Simulation...

Effective management of the operational lifespan is a critical aspect in enhancing reliability modular multilevel converters (MMCs). Typically, distribution switches/diodes each submodule (SM) not uniform. This article puts forward lifetime optimization control (LOC) MMC, where SMs could be improved by injecting optimal second-order harmonic circulating current (SHCC) MMCs. The proposed approach leads to significant enhancement dependability Experiments using PSCAD/EMTDC time-domain...

Energy storage is the key support for new energy power generation, peak shaving, transmission and use. Therefore, development of composite systems in great significance. In this paper, an optimal configuration model system designed wind solar a two-layer decision-making constructed to consider economic benefits battery life upper layer charging discharging strategy lower layer, so as optimize overall framework system. To reduce its full cycle cost much possible improve reliability economy...

The modular multilevel converter (MMC) is promising in the low voltage applications with less submodule (SM) numbers. However, one of significant challenge that output harmonics are relatively high these applications. To improve AC side harmonic characteristics and decrease cost filter, LCL filter introduced into grid-connected MMCs. This paper design parameters based on MMC. In addition, impedance model different device derived to do stability analysis. With proposed method, current...

This paper proposed a sorting-based condition monitoring strategy for capacitors of submodule (SM) in modular multilevel converters (MMCs). It reveals the relationship between capacitor's capacitance and SM insertion time. Based on relationship, capacitances arm are indirectly sorted, only capacitor with smallest monitored. The not realizes MMCs method, but also proposes simplified algorithm large number capacitors. simulation experimental results confirm effectiveness MMCs.