The Experts below are selected from a list of 243120 Experts worldwide ranked by ideXlab platform
B.i. Kwon - One of the best experts on this subject based on the ideXlab platform.
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Winding Switching and Turn Switching in Permanent Magnet Vernier Machines for Wide Speed Range Operation and High Efficiency
IEEE Access, 2019Co-Authors: A. Arif, N. Baloch, B.i. KwonAbstract:This paper proposes to turn to switch along with winding switching for high-efficiency of permanent magnet vernier machines (PMVM) during wide speed Range Operation for electric vehicles application. For winding switching, the three-phase winding of the machine is divided into two sets of windings, namely, winding set A, B, C and winding set X, Y, Z. For turn switching, the number of turns for one set of winding is changed. With the different number of turns for winding set X, Y, Z, the efficiency of the machine can be significantly improved. Initially, the basic electromagnetic characteristics, such as the flux linkage, back electromotive force (EMF), torque, and phase voltages of the machine are investigated using winding switching and turn switching. Then, the output power, torque-speed curve, core losses, efficiency, and power factor of the machine are analyzed in detail using a different number of turns. In addition, the transient effects of winding switching and turn switching have been analyzed. Finally, a control strategy is proposed which combines turn switching and winding switching to ensure high-efficiency of PMVMs during wide speed Range Operation. A PMVM is designed and driven in accordance with the proposed control strategy (PCS) to show the characteristics of PCS. The PMVM driven with PCS is compared to a recently presented PMVM. The recently presented PMVM is driven by a different control strategy and is analyzed with two different kinds of steel laminations that are general steel (50TW470) and special steel (20JHF1300).
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Wide speed Range Operation of permanent magnet vernier machines
Electronics Letters, 2018Co-Authors: A. Arif, N. Baloch, B.i. KwonAbstract:This letter proposes winding switching for the high-performance of permanent-magnet vernier machines (PMVMs) in wide speed Range Operation. The machine is operated in two modes: cumulative and differential. Before winding switching (cumulative mode), the machine is operated like a conventional three-phase PMVM. The machine provides high torque density and high efficiency in this mode. After winding switching (differential mode), the back EMF and inductance of the machine are decreased significantly, which enable wide speed Range Operation and the attainment of high power factor in high-speed Operation.
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Wide Speed Range Operation of Non-Salient PM Machines
IEEE Transactions on Energy Conversion, 2016Co-Authors: Shahid Atiq, Thomas A. Lipo, B.i. KwonAbstract:Non-salient permanent magnet machines are considered poor candidates for flux weakening Operations due to their inherent low-inductance characteristics. In this paper, a two-pole 24-slot non-salient PM machine design is proposed that can utilize a winding switching technique to achieve wide speed Range Operation. A very wide speed Range Operation (from 3 to 1 ratio to as much as 13 to 1) is demonstrated. This is accomplished by simply rearranging the winding coils on the stator periphery. Moreover, a control strategy is proposed that not only utilizes the flux weakening using winding switching, but also flux weakening using a negative d -axis current to maximize the speed Range of the machine. The machine is operated with two inverters to control the current in the machine winding over the entire speed Range. A dq model for the machine is also presented. Analytical, simulated, and experimental results are provided to validate the proposed machine drive system.
Kwang Y. Lee - One of the best experts on this subject based on the ideXlab platform.
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Fuzzy Gain-Scheduling PID+Decoupling Control for Power Plant Wide-Range Operation
2007 International Conference on Intelligent Systems Applications to Power Systems, 2007Co-Authors: R. Garduno-ramirez, Kwang Y. LeeAbstract:Mostly during wide-Range Operation, load-following capability and efficacy for frequency regulation of fossil-fuel power plants may be affected by interaction among the control loops, caused by the non-linear coupled plant dynamics. This paper introduces a fuzzy gain-scheduling decoupling control scheme to improve plant response under large power excursions throughout the power plant operating space. The control scheme consists of single-loop PID controllers in series with an inverse interaction compensator. Both, the controllers and compensator are gain-scheduled with fuzzy systems to embrace the entire operating space. The proposed control scheme is evaluated through simulation experiments. Results show improved wide-Range Operation.
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Compensation of control-loop interaction for power plant wide-Range Operation
Control Engineering Practice, 2005Co-Authors: R. Garduno-ramirez, Kwang Y. LeeAbstract:Power plants are being required to undertake large power variations to satisfy electricity demand, whereas their control systems comprise decentralized control loops and ad-hoc compensation schemes, to deal with loop interaction, for regulation and disturbance rejection at base load. This paper presents a compensation scheme that lessens control loop interaction, caused by the nonlinear coupled process dynamics, to ease power generation control throughout the power plant operating space. Compensation factors are systematically determined from a process gain matrix that conveys all interaction information. Numerical analysis and simulation experiments demonstrate the feasibility of power plant wide-Range Operation with the proposed compensator.
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Wide Range Operation of a Power Unit via Feedforward Fuzzy Control
2000Co-Authors: R. Garduno-ramirez, Kwang Y. LeeAbstract:A two-level hierarchical control scheme for wide-Range Operation of fossil fuel power units is presented. At the supervisory level, a fuzzy reference governor generates, according to a variable pressure operating policy, the set-point trajectories to command the unit along any load demand pattern. At the control level, a feedforward-feedback control strategy is implemented. The feedforward control path contains a set of multi-input single-output fuzzy inference systems, designed from steady-state input-output plant data. The feedback control path consists of PID controllers in a multi-loop configuration, as currently available at power units. With this strategy, the feed- forward path provides most of the control signal for wide-Range Operation, diminishing the control effort on the PID controllers. The feedback path supplies the complementary control signal component for regulation and disturbance rejection in small neighborhoods about the commanded trajectories. Simulation results demonstrate the feasibility of the control scheme to attain cyclic load-following Operation.
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Wide Range Operation of a power unit via feedforward fuzzy control [thermal power plants]
IEEE Transactions on Energy Conversion, 2000Co-Authors: R. Garduno-ramirez, Kwang Y. LeeAbstract:A two-level hierarchical control scheme for wide-Range Operation of fossil fuel power units is presented. At the supervisory level, a fuzzy reference governor generates, according to a variable pressure operating policy, the set-point trajectories to command the unit along any load demand pattern. At the control level, a feedforward-feedback control strategy is implemented. The feedforward control path contains a set of multi-input single-output fuzzy inference systems, designed from steady-state input-output plant data. The feedback control path consists of PID controllers in a multi-loop configuration, as currently available at power units. With this strategy, the feedforward path provides most of the control signal for wide-Range Operation, diminishing the control effort on the PID controllers. The feedback path supplies the complementary control signal component for regulation and disturbance rejection in small neighborhoods about the commanded trajectories. Simulation results demonstrate the feasibility of the control scheme to attain cyclic load-following Operation.
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Neural network for adapting nuclear power plant control for wide-Range Operation
Transactions of the American Nuclear Society, 1991Co-Authors: Kwang Y. Lee, Robert M. EdwardsAbstract:A new concept of using neural networks has been evaluated for optimal control of a nuclear reactor. The neural network uses the architecture of a standard backpropagation network; however, a new dynamic learning algorithm has been developed to capture the underlying system dynamics. The learning algorithm is based on parameter estimation for dynamic systems. The approach is demonstrated on an optimal reactor temperature controller by adjusting the feedback gains for wide-Range Operation. Application of optimal control to a reactor has been considered for improving temperature response using a robust fifth-order reactor power controller. Conventional gain scheduling can be employed to extend the Range of good performance to accommodate large changes in power where nonlinear characteristics significantly modify the dynamics of the power plant. Gain scheduling is developed based on expected parameter variations, and it may be advantageous to further adapt feedback gains on-line to better match actual plant performance. A neural network approach is used here to adapt the gains to better accommodate plant uncertainties and thereby achieve improved robustness characteristics.
T M Jahns - One of the best experts on this subject based on the ideXlab platform.
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comparison of synchronous pm machine types for wide constant power speed Range Operation
Compel-the International Journal for Computation and Mathematics in Electrical and Electronic Engineering, 2008Co-Authors: Ayman Mohamed Fawzi Elrefaie, T M JahnsAbstract:Purpose – The purpose of this paper is to provide a comparison of synchronous permanent magnet machine types for wide constant power speed Range Operation.Design/methodology/approach – A combination of analytical models and finite element analysis is used to conduct this study.Findings – The paper has presented a detailed comparison between various types of synchronous PM machines for applications requiring a wide speed Range of constant‐power Operation. Key observations include: surface permanent magnet (SPM) and interior permanent magnet (IPM) machines can both be designed to achieve wide speed Ranges of constant‐power Operation. SPM machines with fractional‐slot concentrated windings offer opportunities to minimize machine volume and mass because of their short winding end turns and techniques for achieving high‐slot fill factors via stator pole segmentation. High back‐emf voltage at elevated speeds is a particular issue for SPM machines, but also poses problems for IPM machine designs when tight maxim...
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effect of back emf constraints on fractional slot surface pm machines designed for wide constant power speed Range Operation
Electric Power Components and Systems, 2008Co-Authors: Ayman Mohamed Fawzi Elrefaie, T M Jahns, John W MckeeverAbstract:Abstract This article investigates the tradeoffs that result from constraining the back-emf at maximum speed for fractional-slot surface permanent magnet (SPM) machines. Two 55 kW (peak) SPM machines designed to meet requirements established in the US FreedomCar program are used as the basis for this investigation. The two machines are 36-slot/30-pole SPM fractional-slot concentrated-winding designs that use sintered NdFeB magnets. The first design has no back-emf constraint at maximum speed, allowing it to exceed the 600 V pk l-l limit, while the second design has been designed to meet this requirement. Results of this study show that the introduction of back-emf limits can lead to significant increases in the SPM machine's rated current, with only a modest impact on the machines mass and volume. A combination of closed-form analysis and finite element analysis is used to carry out this investigation.
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impact of winding layer number and magnet type on synchronous surface pm machines designed for wide constant power speed Range Operation
IEEE Industry Applications Society Annual Meeting, 2006Co-Authors: Ayman Mohamed Fawzi Elrefaie, T M JahnsAbstract:This paper thoroughly investigates the impact of the winding layer number and the choice of magnet type on the performance characteristics of surface permanent magnet (SPM) machines with fractional-slot concentrated windings designed for wide speed Ranges of constant-power Operation. This is accomplished by carefully examining the performance characteristics of three different SPM machines designed for the same set of performance requirements drawn from an automotive direct-drive starter/alternator application. These results show that double-layer stator windings yield lower torque ripple and magnet eddy-current losses than single-layer windings, but can contribute to a lower overload torque capability. Although the adoption of sintered magnets leads to the highest machine torque density, bonded magnets result in a significant reduction of the magnet losses because of their much higher value of resistivity.
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comparison of synchronous pm machine types for wide constant power speed Range Operation
IEEE Industry Applications Society Annual Meeting, 2005Co-Authors: Ayman Mohamed Fawzi Elrefaie, T M JahnsAbstract:This paper presents a detailed comparison of the high-speed operating characteristics of four synchronous PM machines for applications that require wide speed Ranges of constant-power Operation. These machines include surface PM machines with both distributed and fractional-slot concentrated windings, and two interior PM machine with distributed windings. These two versions of the interior PM machine include one with and a tight constraint on the machine's back-emf voltage at top speed and one without this constraint The target application is an automotive direct-drive starter/alternator requiring a very wide 10:1 constant power speed ratio (CPSR). Detailed comparisons of the performance characteristics of the machines are presented that include important issues such as the back-emf voltage at top speed, machine mass and cost, and eddy current losses in the magnets. Analytical results are verified using finite element analysis (FEA). Guidelines are developed to help drive designers decide which type of machine is most suitable for high-CPSR applications. Tradeoffs associated with choosing each of these machines are presented.
Ayman Mohamed Fawzi Elrefaie - One of the best experts on this subject based on the ideXlab platform.
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comparison of synchronous pm machine types for wide constant power speed Range Operation
Compel-the International Journal for Computation and Mathematics in Electrical and Electronic Engineering, 2008Co-Authors: Ayman Mohamed Fawzi Elrefaie, T M JahnsAbstract:Purpose – The purpose of this paper is to provide a comparison of synchronous permanent magnet machine types for wide constant power speed Range Operation.Design/methodology/approach – A combination of analytical models and finite element analysis is used to conduct this study.Findings – The paper has presented a detailed comparison between various types of synchronous PM machines for applications requiring a wide speed Range of constant‐power Operation. Key observations include: surface permanent magnet (SPM) and interior permanent magnet (IPM) machines can both be designed to achieve wide speed Ranges of constant‐power Operation. SPM machines with fractional‐slot concentrated windings offer opportunities to minimize machine volume and mass because of their short winding end turns and techniques for achieving high‐slot fill factors via stator pole segmentation. High back‐emf voltage at elevated speeds is a particular issue for SPM machines, but also poses problems for IPM machine designs when tight maxim...
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effect of back emf constraints on fractional slot surface pm machines designed for wide constant power speed Range Operation
Electric Power Components and Systems, 2008Co-Authors: Ayman Mohamed Fawzi Elrefaie, T M Jahns, John W MckeeverAbstract:Abstract This article investigates the tradeoffs that result from constraining the back-emf at maximum speed for fractional-slot surface permanent magnet (SPM) machines. Two 55 kW (peak) SPM machines designed to meet requirements established in the US FreedomCar program are used as the basis for this investigation. The two machines are 36-slot/30-pole SPM fractional-slot concentrated-winding designs that use sintered NdFeB magnets. The first design has no back-emf constraint at maximum speed, allowing it to exceed the 600 V pk l-l limit, while the second design has been designed to meet this requirement. Results of this study show that the introduction of back-emf limits can lead to significant increases in the SPM machine's rated current, with only a modest impact on the machines mass and volume. A combination of closed-form analysis and finite element analysis is used to carry out this investigation.
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impact of winding layer number and magnet type on synchronous surface pm machines designed for wide constant power speed Range Operation
IEEE Industry Applications Society Annual Meeting, 2006Co-Authors: Ayman Mohamed Fawzi Elrefaie, T M JahnsAbstract:This paper thoroughly investigates the impact of the winding layer number and the choice of magnet type on the performance characteristics of surface permanent magnet (SPM) machines with fractional-slot concentrated windings designed for wide speed Ranges of constant-power Operation. This is accomplished by carefully examining the performance characteristics of three different SPM machines designed for the same set of performance requirements drawn from an automotive direct-drive starter/alternator application. These results show that double-layer stator windings yield lower torque ripple and magnet eddy-current losses than single-layer windings, but can contribute to a lower overload torque capability. Although the adoption of sintered magnets leads to the highest machine torque density, bonded magnets result in a significant reduction of the magnet losses because of their much higher value of resistivity.
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comparison of synchronous pm machine types for wide constant power speed Range Operation
IEEE Industry Applications Society Annual Meeting, 2005Co-Authors: Ayman Mohamed Fawzi Elrefaie, T M JahnsAbstract:This paper presents a detailed comparison of the high-speed operating characteristics of four synchronous PM machines for applications that require wide speed Ranges of constant-power Operation. These machines include surface PM machines with both distributed and fractional-slot concentrated windings, and two interior PM machine with distributed windings. These two versions of the interior PM machine include one with and a tight constraint on the machine's back-emf voltage at top speed and one without this constraint The target application is an automotive direct-drive starter/alternator requiring a very wide 10:1 constant power speed ratio (CPSR). Detailed comparisons of the performance characteristics of the machines are presented that include important issues such as the back-emf voltage at top speed, machine mass and cost, and eddy current losses in the magnets. Analytical results are verified using finite element analysis (FEA). Guidelines are developed to help drive designers decide which type of machine is most suitable for high-CPSR applications. Tradeoffs associated with choosing each of these machines are presented.
Shahid Atiq - One of the best experts on this subject based on the ideXlab platform.
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Wide Speed Range Operation of Non-Salient PM Machines
IEEE Transactions on Energy Conversion, 2016Co-Authors: Shahid Atiq, Thomas A. Lipo, B.i. KwonAbstract:Non-salient permanent magnet machines are considered poor candidates for flux weakening Operations due to their inherent low-inductance characteristics. In this paper, a two-pole 24-slot non-salient PM machine design is proposed that can utilize a winding switching technique to achieve wide speed Range Operation. A very wide speed Range Operation (from 3 to 1 ratio to as much as 13 to 1) is demonstrated. This is accomplished by simply rearranging the winding coils on the stator periphery. Moreover, a control strategy is proposed that not only utilizes the flux weakening using winding switching, but also flux weakening using a negative d -axis current to maximize the speed Range of the machine. The machine is operated with two inverters to control the current in the machine winding over the entire speed Range. A dq model for the machine is also presented. Analytical, simulated, and experimental results are provided to validate the proposed machine drive system.
