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The penetration of renewable power plants in the global electricity mix is reaching significant levels, and power system operators are adapting their grid codes, so that renewable generators do not alter the operation of the grid, preventing the introduction of additional disturbances and contributing to the control of the power system. In this context, hybrid solar plants arise as a tradeoff solution...
This paper presents a medium voltage power conversion architecture for grid integration of multi-MW permanent magnet synchronous generator (PMSG) based wind energyc-conversion system (WECS). Converting the low voltage power output of the generator to medium voltage, can reduce the diameter of the power cable significantly. As a result, power loss and the overall cost of the system can be minimized...
We consider the fundamental derandomization problem of deterministically finding a satisfying assignment to a CNF formula that has many satisfying assignments. We give a deterministic algorithm which, given an n-variable \poly(n)-clause CNF formula F that has at least ≥ 2^n satisfying assignments, runs in time \[ n^{\tilde{O}(\log\log n)^2} \] for ≥ \ge 1/\polylog(n) and outputs...
This paper presents test results of the control of a pole-modulated permanent magnet synchronous generator (PM-PMSG) using a dedicated power conversion system to deliver power from an oscillating, low speed wave energy converter (WEC). Due to the low speed of the WEC, the size of the generator is increased and the machine is designed with large number of poles and concentrated winding. The electromotive...
This paper presents a compact power control unit (PCU) for hybrid electric vehicles. The authors use silicon carbide (SiC) MOSFET power modules with insulated ceramic substrates, resulting in high thermal conductivity. In addition, direct connection of aluminum-made chassis of a reactor and a capacitor to the heat sink makes it possible to highly release heat generation of them. These two measures...
This paper introduces the high voltage generation architectures derivation methodology and comparative evaluation of high voltage power generation architectures based on the key performance items such as efficiency, power density, high voltage pulse speed, high voltage pulse ripple, HV insulation and scalability for different output voltage and output power ratings. Based on comparative evaluation...
Energy harvesting is an attractive option to generate power for different low power stand-alone electronic devices. Dielectric Elastomer Generator (DEG) is a special variable capacitor generator which, by virtue of its variable capacitance property, can convert vibrational mechanical energy to electrical energy. Hence the DEGs can be used as a means to harvest electrical energy from various environmental...
This work faces the problem of frequency deviation in microgrid systems. The considered microgrid includes renewable energy sources such as wind and solar photovoltaic. As long as these sources provide an irregular power supply or there is a sudden change in the system load, the power system frequency deviates. In order to compensate such deviations, alternative, conventional energy sources should...
Proposed here is a Fault Tolerant Control (FTC) design for nonlinear power systems with unknown actuator failures. The method is based on the efficient multi input-multi-output linearization technique. The power system considered here is consisted of two generators along with a load and an infinite bus via a transmission network. First, the derivatives of the system's output is calculated repeatedly,...
This paper presents the design, construction, and testing of a double-sided, dual airgap linear Vernier generator for wave energy conversion. Both the electromagnetic as well as mechanical design concepts are explored with a particular emphasis on the mechanical aspect given the fact that maintaining a dual airgap for this topology is challenging and has not been previously implemented.
In an Organic Rankine Cycle (ORC) systems, the Permanent Magnet (PM) generator is directly coupled to high-speed turbine shaft, in order to increase system efficiency avoiding introduction of gear-box. On the other hand, current time harmonics induce high frequency currents in rotor parts, which cause a temperature increase. PMs are strongly affected by the operating temperature, since both remanence...
High reliability is extremely important for uninterruptable power supplies (UPS) such as those used in the modern data centers. It is necessary to comprehensively and precisely evaluate reliability of different UPS system's architectures before constructing the data center. In this paper, a novel reliability analysis and simulation tool for data center power distribution system is proposed. The basic...
Power quality of ac bus voltage is a key issue for microgrids. A model-predictive-control (MPC)-based distributed bus voltage compensation methods using inverter-interfaced distributed generators (DGs) connected to the concerned bus is proposed. The presented method can compensate bus voltage unbalance and harmonics and share the compensated current between inverters autonomously, with neither communication...
This paper analyzes an effect of voltage feedforward control in order to improve stability of BESS which is connected to diesel generator in stand-alone microgrid. In the stand-alone microgrid, BESS can be charged from the diesel generator when SOC of battery bank is insufficient, where BESS operates as CC-CV control. In this case, although LCL filter is designed to put a resonance point greater than...
Contrary to popular belief, mobile apps can spend a large fraction of time running "hidden" as background services. And, bugs in services can translate into crashes, energy depletion, device slow-down, etc. Unfortunately, without necessary testing tools, developers can only resort to telemetries from user devices in the wild. To this end, Snowdrop is a testing framework that systematically...
Automatically generating unit tests is a powerful approach to exercise complex software. Unfortunately, current techniques often fail to provide relevant input values, such as strings that bypass domain-specific sanity checks. As a result, state-of-the-art techniques are effective for generic classes, such as collections, but less successful for domain-specific software. This paper presents TestMiner,...
Dataflow models of computation have early on been acknowledged as an attractive methodology to describe parallel algorithms, hence they have become highly relevant for programming in the current multicore processor era. While several frameworks provide tools to create dataflow descriptions of algorithms, generating parallel code for programmable processors is still sub-optimal due to the scheduling...
Since physical unclonable functions (PUFs) are considered for various security applications such as authentication and key generation, the robustness of PUFs is vital. In prior works, various error correction codes, such as Bose-Chaudhuri-Hocquenghem (BCH) codes, were used to improve the robustness of PUFs. In this paper, we use polar codes, a new family of error correction codes, to improve the robustness...
Security protocols are critical components for the construction of secure and dependable distributed applications, but their implementation is challenging and error prone. Therefore, tools for formal modelling and analysis of security protocols can be potentially very useful to support software engineers. However, despite such tools have been available for a long time, their adoption outside the research...
Usage-based statistical testing employs knowledge about the actual or anticipated usage profile of the system under test for estimating system reliability. For many systems, usage-based statistical testing involves generating synthetic test data. Such data must possess the same statistical characteristics as the actual data that the system will process during operation. Synthetic test data must further...
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