scholarly journals A Steady-State Equivalent Circuit of TSCAOI Configured Induction Generator for Renewable Energy Conversion Systems

2021 ◽  
Vol 6 (1) ◽  
pp. 20-30
Author(s):  
Zhijia Wang ◽  
Keyword(s):  
Renewable Energy ◽  
Steady State ◽  
Energy Conversion ◽  
Equivalent Circuit ◽  
Equivalent Circuit Model ◽  
Operating Conditions ◽  
Voltage Unbalance ◽  
Energy Conversion Systems ◽  
State Behaviour ◽  
And Performance

3-phase cage induction machines, operated in two series-connected and one-isolated (TSCAOI) winding configuration, have been proposed to generate standalone single-phase electricity at variable speeds for renewable energy conversion systems. However, the steady-state behaviour and performance of this particular generator are not yet to be theoretically investigated. This paper therefore presents the first theoretical investigation based on the steady-state equivalent circuit model for standalone TSCAOI configured generators. Moreover, this paper is the first to adopt the winding function approach to derive a dynamic mathematical model for TSCAOI configured generators. This approach not only eliminates the cumbersome mathematical manipulation required in all previous papers related to TSCAOI configured generators but also provides a visual insight into the resulting winding distribution of the machine. In order to investigate the load and excitation characteristics pertinently, the dynamic model is transformed into two different equivalent circuit models by appropriate selected transformation matrix. Using these two models, this paper identified the impacts of system parameters on the load and excitation characteristics, as well as on the level of voltage unbalance. Experimental results of a prototype generator under various operating conditions are presented, together with simulated results, to demonstrate the accuracy of the proposed investigations.

scholarly journals Data–Driven Control Techniques for Renewable Energy Conversion Systems: Wind Turbine and Hydroelectric Plants

2019 ◽  
Author(s):  
Silvio Simani ◽  
Stefano Alvisi ◽  
Mauro Venturini
Keyword(s):  
Renewable Energy ◽  
Energy Conversion ◽  
Wind Turbine ◽  
Control Strategies ◽  
Operating Conditions ◽  
Renewable Energy Resources ◽  
Control Techniques ◽  
Wide Range ◽  
Energy Conversion Systems ◽  
Hydroelectric Plants

The interest on the use of renewable energy resources is increasing, especially towards wind and hydro powers, which should be efficiently converted into electric energy via suitable technology tools. To this aim, data--driven control techniques represent viable strategies that can be employed for this purpose, due to the features of these nonlinear dynamic processes working over a wide range of operating conditions, driven by stochastic inputs, excitations and disturbances. Some of the considered methods, such as fuzzy and adaptive self--tuning controllers, were already verified on wind turbine systems, and similar advantages may thus derive from their appropriate implementation and application to hydroelectric plants. These issues represent the key features of the work, which provides some guidelines on the design and the application of these control strategies to these energy conversion systems. The working conditions of these systems will be also taken into account in order to highlight the reliability and robustness characteristics of the developed control strategies, especially interesting for remote and relatively inaccessible location of many installations.

scholarly journals Radioisotope Thermophotovoltaic Generator Design and Performance Estimates for Terrestrial Applications

2017 ◽  
Author(s):  
Xiawa Wang ◽  
Walker Chan ◽  
Veronika Stelmakh ◽  
Peter Fisher
Keyword(s):  
Heat Source ◽  
Energy Conversion ◽  
Heat Sink ◽  
Electrical Power ◽  
Equivalent Circuit Model ◽  
Operating Conditions ◽  
And Performance ◽  
Heat Sink Design ◽  
Performance Estimates ◽  
Source Number

This work provides the design methods and performance estimates of the radioisotope thermophotovoltaic system (RTPV) for terrestrial applications. The modeling is based on an experimentally tested prototype using two-dimensional high temperature photonic crystal to realize spectral control. The design efforts focus on the optimization of the system efficiency and contain the heat source number, the size of the energy conversion elements, the insulation configuration, and the heat sink design. An equivalent circuit model was developed for the thermal and electrical performances. Based on a specific output requirement, an optimized heat source number and energy conversion area can be computed for a certain cell type and insulation design. The selection and characterization of the low bandgap thermophotovoltaic (TPV) cells applicable to the generator are compared and discussed. The generator’s heat sink design uses extended fins and the performance is estimated based on the external operating conditions. Finally, the work provides a design example of a terrestrial RTPV generator with an output level of ∼40 W electrical power (We) using InGaAsSb cell, reaching an efficiency of 8.26%.

Design and Performance of a Controlled Turbocharging System on Marine Diesel Engines

2006 ◽  
Author(s):  
Ioannis Vlaskos ◽  
Ennio Codan ◽  
Nikolaos Alexandrakis ◽  
George Papalambrou ◽  
Marios Ioannou ◽  
...  
Keyword(s):  
Steady State ◽  
Engine Performance ◽  
Operating Conditions ◽  
Electric Actuator ◽  
Engine Simulation ◽  
Engine Control System ◽  
Turbocharging System ◽  
Compressor Impeller ◽  
Marine Diesel ◽  
And Performance

The paper describes the design process for a controlled pulse turbocharging system (CPT) on a 5 cylinder 4-stroke marine engine and highlights the potential for improved engine performance as well as reduced smoke emissions under steady state and transient operating conditions, as offered by the following technologies: • controlled pulse turbocharging, • high pressure air injection onto the compressor impeller as well as into the air receiver, and • an electronic engine control system, including a hydraulic powered electric actuator. Calibrated engine simulation computer models based on the results of tests performed on the engine in its baseline configuration were used to design the CPT components. Various engine tests with CPT under steady state and transient operating conditions show the engine optimization process and how the above-mentioned technologies benefit engine behavior in both generator and propeller law operation.

Operation and Control of a Supercritical CO2 Compressor

2021 ◽  
Author(s):  
Joshua D. Neveu ◽  
Stefan D. Cich ◽  
J. Jeffrey Moore ◽  
Jason Mortzheim
Keyword(s):  
Steady State ◽  
Critical Point ◽  
Operating Conditions ◽  
State Control ◽  
Power Cycle ◽  
Low Head ◽  
And Performance ◽  
Steady State Control ◽  
And Control ◽  
Thermal Sources

Abstract Among the list of advanced technologies required to support the energy industry’s novel Supercritical Carbon Dioxide (sCO2) power cycle is the need for a robust and responsive control system. Recent testing has been performed on a 2.5 MWe sCO2 compressor operating near the critical temperature (31C) and critical pressure (73.8 bar), developed with funding from the US DOE Apollo program and industry partners. While sCO2 compression has been performed before, operating near the critical point has many key benefits for power generation with its low head requirements and smaller physical footprint. However, with these benefits come unique challenges, namely controlling this system to steady-state operating conditions. Operating just above the critical point (35°C [95°F] and 8.5 MPa [1,233 psi]) there can be large and rapid swings in density produced by subtle changes in temperature, leading to increased difficulty in maintaining adequate control of the compressor system. This means that proper functionality of the entire compressor system, and its usefulness to a closed loop recompression Brayton power cycle, is largely dependent on variables such as thermal sources, precision and response time of the instrumentation, proper heat soaking, and strategic filling and venting sequences. While other papers have discussed the science behind and performance of sCO2 compressors, this paper will discuss the challenges associated with steady-state control of the compressor at or near operating conditions, how the fill process was executed for optimal startup, and changes that occurred while idling during trip events.

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