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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...
The Cascaded multilevel inverters are popular in high-power medium-voltage drives because of their modularity and high power handling capacity. An efficient, systematic fault detection scheme is necessary for the reliable operation of the drive. In this paper, a novel open switch fault diagnosis for the three-phase cascaded H-bridge inverter-fed induction motor drive based on the discrete wavelet...
This paper puts forth a vision for scalable distribution grid integration of energy resources such as rooftop photovoltaics (PVs) and electric vehicles (EVs). The output of these resources vary temporally in an unpredicted manner. Therefore, they bring substantial challenges to utilities vis-a-vis massive deployment of such resources. By leveraging the fact that most of the distributed energy resources...
Multiphase machines have several advantages and are attractive for some applications. Reliability is one of the most important of those advantages. Faults commonly occur in inverter switches and stator windings. In the case of an inverter-fed nine-phase induction machine drive, this paper focuses on experimental results, comparisons and analysis of several types of inverter and machine faults: one,...
Nowadays, research on the reliability improvement of T-type three-level inverters is studied as an important issue. In this paper, a novel fault tolerant control strategy based on model predictive control (MPC) is proposed for open-circuit faults in switch devices. When an open-circuit fault occurs to neutral-point switches, the impossible switching states of zero- and small-voltage vectors should...
Due to the advantages of cost, volume and efficiency, transformerless grid-connected power converters have drawn an increasing attention, especially in low-power PV applications. However, the lack of isolation between inverter and grid brings in some potential risks to the distribution network. Among them, the dc injection flows into the grid remains a significant concern. Owing to the offset and...
A low voltage ride-through solution for an indirect three-level matrix converter based open-end winding drive is demonstrated. The proposed method uses the input filter capacitors to exchange the inertial energy from the motor and thereby maintain the flux in the motor during grid fault conditions. The input filter capacitors act as the voltage source for inverters during the fault. Ride-through is...
This paper presents theoretical and experimental discussions on low-voltage-ride-through (LVRT) operation of a modular multilevel single-delta bridge-cell (SDBC) inverter intended for utility-scale photovoltaic (PV) systems. As the penetration of distributed generation from renewable energy sources connected to medium- and high-voltage grids increases, grid-tied inverters progressively need to abide...
In this paper, a method to diagnose and identify the open-circuit faults of IGBT for a six-level hybrid inverter (6L-HI) is proposed, which is based on the signals of the inner device voltages, the flying capacitor voltages and the phase currents of the inverter. Since the flying capacitor voltage sensors and the output current sensors are already employed for the inverter operation, only one additional...
On the basis of establishing mathematical model of induction machine, the simplifying assumption of two-dimensional plane finite element model was proposed, and Dirichlet and main boundary conditions were defined. The speed governing of induction machine was realized using back-to-back voltage-fed frequency converter. The continuous output direct voltage value of three-phase non-controlled rectifier...
This paper presents an optimized active power control method for two-stage photovoltaic (PV) grid-connected inverter under unbalanced grid faults. The purpose of the control method is to reduce the active power deficit of grid by injecting the maximum active power of the PV system under the premise of ensuring the safety of the inverter itself. Safe operation region (SOR), which considers the limitation...
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...
The multiplex 3-phase winding motors suffer from the problem of the magnetic coupling between the normal winding and the fault winding. To investigate the behaviors of the dual-winding PMSMs on the short-circuited fault conditions, a fault analysis model is developed that includes a dual-winding PMSM circuit model with a short-circuited fault coil within some phase coil and an inverter model with...
In this paper, a novel configuration of the back-to-back (BTB) converter interconnecting two synchronous AC grids is proposed. The feature of this BTB converter configuration is the substantially reduced capacity compared with the exchanged power between the two grid partitions. Unlike the conventional full-capacity BTB converters, the capacity of the proposed BTB converter in this paper is around...
A microgrid powered by inverters has become a typical approach to efficient use of renewable energy source. However, the behavior of constantcurrent of the inverters will make it difficult to protect the network. To solve this problem, this paper offers the directional interlocking overcurrent protection for the microgrid powered by the inverters injected with characteristic current. When a fault...
The permanent magnet synchronous motor (PMSM) supplied by an inverter plays key roles in the critical application. Therefore, many efforts have been paid to the fault tolerant of the PMSM drive system to ensure the system continue operate in the postfault situation. Fault tolerant include fault detection and fault diagnosis> remedial action combinationing of hardware and software reconfigurations...
In this paper, we conduct a data-driven experimental analysis on a single-phase-to-neutral fault at a distribution grid in Riverside, CA using data from five distribution level phasor measurement units, a.k.a, Micro-PMUs. Of particular interest is to extract the time-line during the fault. With the high resolution, precision, and time synchronization of the data from Micro-PMUs, the hypothesis about...
Matsuda et al. proposed a countermeasure against laser fault injection that uses distributed on-chip sensors. The sensor raises an alarm by detecting an electrical phenomenon caused in conjunction with a bitflip. A cryptographic module can stop releasing a faulty ciphertext by using the alarm. In this paper, security and limitation of the countermeasure by Matsuda et al. is rigorously evaluated. We...
This paper presents a technique for the fault-based test of the analog amplifiers. The circuit defects are modeled with the 2-fault transistor models. The test method combines the amplifier evaluation both in and out of the normal operating region, with the transconductance of the amplifier being the key test parameter. Furthermore, the additional low current test is employed in order to maximize...
The aim of this work is to evaluate the impact of the incorporation of dynamic voltage support and reactive power injection requirements in PV systems connected at Provincial Interconnected System(PIS) of San Juan-Argentina projected up to the year 2024 under different levels of penetration. To this aim, the calculation of a severity indexes is proposed. It can be concluded that the capacity to withstand...
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