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A reliable multilevel inverter with fault tolerance is proposed. It consists of two sources and six switches. The unipolarity voltage level produced by the proposed inverter is transformed to dual polarity with the help of H-bridge. The proposed inverter produces maximum 9 levels output voltage with asymmetrical source and 5 levels output voltage with symmetrical source in healthy condition. During...
This article presents a method of the automated control of distributed radio direction finding system (RDFS) providing the construction of an automated system of technical diagnostics and recovery of distributed RDFS performance on the specified requirements. This dual-circuit method includes diagnosing and reliability operations, redundancy recommendations, and also control algorithms of the constituent...
By using the zigzag transformer, the scheme of medium-voltage simultaneous AC and DC distribution network is designed. The topological structure of power router is put forward based on the simultaneous AC and DC distribution network. The feasibility of the simultaneous AC and DC distribution network and power router are verified by using MATLAB/Simulink. Taking line voltage drop and line loss as performance...
This paper proposes a new high-voltage Pulse Generator (PG), fed from low voltage dc supply Vs. This input supply voltage is utilized to charge two arms of N series-connected modular multilevel converter sub-module capacitors sequentially through a resistive-inductive branch, such that each arm is charged to NVS. With a step-up nano-crystalline transformer of n turns ratio, the proposed PG is able...
In this paper, an asymmetric mixed MMC topology of multilevel converter for bipolar HVDC transmission systems is introduced. Among the existing MMC topologies for the bipolar HVDC systems, the asymmetric mixed MMC topology provides the benefits of: a lower number of submodule cells, fewer switching devices and lower conduction losses. Furthermore, the HVDC based on asymmetric mixed MMC can be flexibly...
Hybrid DC circuit breaker, a combination of disconnector and multiple power electronic devices, has gained popularity for its low-loss at normal operation and its quick and effective circuit breaking during fault protection. However, its bulkiness threatens to limit its application in multi-terminal DC system, where the terminal is usually connected to more than one transmission lines and hence the...
Since the traditional half-bridge modular multilevel converter (HB-MMC) is endangered under DC side short-circuit faults. This paper proposes a novel sub-module (SM) topology for MMC with DC fault limitation capability. The fault current is fully transferred to the bypass thyristor by turning off all IGBTs when DC short-circuit fault occurs, then the diode freewheeling effect is eliminated and all...
This paper proposes a new modular multilevel converter with symmetric bidirectional DC fault blocking capability for high voltage direct current transmission systems. The new modular multilevel converter is composed of novel submodules, which is developed from a three-level T-type converter combined with some clamp circuits. The proposed novel submodule can output three voltage levels with six IGBTs,...
The interleaved bidirectional DC-DC converter is a core component of the battery energy storage system. However, if an open-switch fault occurs at the interleaved bidirectional DC-DC converters, the currents of two branches will become unbalanced, which will increase the battery current ripple and shorten the life of batteries and energy storage systems. In this paper, a fault tolerant topology is...
DC fault protection is one of the biggest challenge to multi-terminal direct current (MTDC) systems, because DC current has no natural zero crossing point. To overcome this problem, hybrid DC circuit breaker (DCCB), which serves as a promising solution to the isolation of DC faults, has been developed. However, hybrid DCCB contains a huge number of power semiconductors, which is costly and inefficient...
The hybrid high voltage direct current (Hybrid HVDC) system based on line commutated converter (LCC) and modular multilevel converter (MMC) is a feasible solution for long distance bulk power transmission. In order to handle the dc-side short-circuit fault, two kinds of methods can be adopted. The first one is to replace half-bridge sub-modules (HBSMs) with full-bridge SMs or clamp-double SMs which...
Active neutral point clamped (ANPC) converter was developed in order to improve the performances of the neutral point clamped (NPC) converter in terms of the semiconductor loss distribution. Loss distribution depends primarily on modulation type used for generation of the switching signals, therefore it is important to find the appropriate modulation type that will allow the most uniform loss distribution...
A modular-multilevel (MMC) DC/DC converter is proposed in this paper, which can be deployed to inter-connect DC grid of different voltage levels, especially in the new energy sources such as wind power and solar power grid connection. Its key features include: 1) step-up and step-down operation. 2) bidirectional power flowing. 3) bi-directional fault blocking similar to a DC breaker. The operation...
In this paper, two new hCB concepts for DC-grids are presented, which use a pulse current to extinguish the arc in the mechanical switch after opening. Both concepts are capable to adjust the pulse current amplitude/waveform to the fault current amplitude and so generate a slow current slope di/dt directly before the zero current crossing without large passive components for a fast and reliable fault...
Ferroelectret films are a relatively new material. Highly anisotropic polymers can be polarized resulting in a piezoelectric response. Advances in manufacturing techniques and polarization have made this technology a viable option in various applications: pressure sensors, air transducers (0.05 MHz–0.6 MHz) and in configuration of patch transducers as pulse sensors and for Lamb waves. Previous experience...
Based on Time-Domain Reflectometry (TDR) technique, a new method which could reconstruct the topology of an unknown or partially unknown network is proposed in this paper. This approach, the TDR-NEW approach, allows the network to be retrieved by drawing its interconnections and estimating the lengths of branches. Two complementary steps are addressed. In the first step the direct problem is modeled...
Modular Multilevel Converter (MMC) has served as a promising Voltage Source Converter (VSC) for High Voltage Direct Current (HVDC) applications. In this paper, a new MMC Submodule (SM) topology called Modified Switched Capacitor Sub-Module (MSCSM) is proposed. The MSCSM is able to block the DC fault using the power electronics semiconductor diodes due to its intelligent configuration without the need...
This paper proposes a generalized logic-based method for fault diagnosis in multilevel inverters that can be integrated with reconfiguration methods. Thus, both effective fault diagnosis and fault tolerance can be accomplished. To validate such integration, the proposed fault diagnosis method is applied to a five-level neutral point clamped inverter with three reconfiguration methods proposed in the...
This paper deals with the fault effects analysis and diagnosis in 6-Φ PMSM designed for aerospace applications. The addressed work aims to analyze the features offered by the space vector theory applied to these systems for fault detection and identification purposes. The paper starts with a presentation of the overall electric drive system structure and its control. Then, fault effects analysis under...
ISOV (Input Series Output Parallel) modular DAB (Dual Active Bridge) converter based topologies have been mostly considered for solid-state transformer (SST) based power substation design, involving multilevel converters at the medium-voltage side. As DAB converter is one of the core components of this topology, an important question to address is thus the freewheeling currents of DAB which increases...
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