Applied Sciences

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12 pages, 4600 KiB

Open AccessArticle

Experimental Verification and Analytical Approach for Electromagnetic Characteristics of a High-Speed Permanent Magnet Motor with Two Different Rotors and Winding Patterns

by Jong-Hyeon Woo, Tae-Kyoung Bang, Jeong-In Lee, Hoon-Ki Lee and Jang-Young Choi

Appl. Sci. 2021, 11(19), 9060; https://doi.org/10.3390/app11199060 - 28 Sep 2021

Cited by 1 | Viewed by 1770

Abstract

In general, high-speed machines should be designed with high efficiency electromagnetic and mechanical characteristics. It is important to analyze the electromagnetic loss for a design with high efficiency. In this study, the effects of the magneto–motive force and time harmonics of the stator [...] Read more.

In general, high-speed machines should be designed with high efficiency electromagnetic and mechanical characteristics. It is important to analyze the electromagnetic loss for a design with high efficiency. In this study, the effects of the magneto–motive force and time harmonics of the stator current according to the winding distribution of a high-speed permanent magnet motor on the electromagnetic characteristics were comparatively analyzed using analytical methods and FEM. In addition, the final model was proposed by analyzing the relationship between the magnet usage according to the rotor shape and the electromagnetic and mechanical properties according to the winding patterns. Finally, the optimal model was manufactured and the validity was experimentally verified. Full article

(This article belongs to the Special Issue Design and Analysis of Electrical Machines and Drives)

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22 pages, 4371 KiB

Open AccessArticle

Optimal Design of a Six-Phase Permanent-Magnet-Assisted Synchronous Reluctance Motor to Convert into Three Phases for Fault-Tolerant Improvement in a Traction System

by Daeil Hyun, Donghan Yun and Jeihoon Baek

Appl. Sci. 2021, 11(18), 8508; https://doi.org/10.3390/app11188508 - 13 Sep 2021

Cited by 4 | Viewed by 2874

Abstract

A six-phase motor with a high degree of freedom can be converted into a three-phase motor in order to be used in a traction system. In addition, when phase-change technology is applied, it is possible to establish an efficient control strategy tailored to [...] Read more.

A six-phase motor with a high degree of freedom can be converted into a three-phase motor in order to be used in a traction system. In addition, when phase-change technology is applied, it is possible to establish an efficient control strategy tailored to the driving environment of the EVs. Therefore, in this paper, a down-scaled 3 kW permanent-magnet-assisted synchronous motor (PMa-SynRM) capable of phase switching was designed, and its driving states in controlled fault modes were analyzed through experiments. The PMa-SynRM selected for this study was a machine that had good fault-tolerance capabilities and was less expensive than an IPMSM with the same performance; it was designed using the lumped-parameter method (LPM) having a fast calculating speed and a genetic algorithm. In addition, the effectiveness of the optimal design was verified by comparing the analytical results of the FEM and the LPM. Lastly, a phase switching experiment was conducted to analyze the steady-state and transient-state characteristics, and the results are presented. Full article

(This article belongs to the Special Issue Design and Analysis of Electrical Machines and Drives)

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27 pages, 16836 KiB

Open AccessArticle

Optimal Design Analysis with Simulation and Experimental Performance Investigation of High-Power Density Telecom PFC Converters

by Ahmed H. Okilly and Jeihoon Baek

Appl. Sci. 2021, 11(17), 7911; https://doi.org/10.3390/app11177911 - 27 Aug 2021

Cited by 8 | Viewed by 3347

Abstract

The spread of the 5G technology in the telecom power applications increased the need to supply high power density with higher efficiency and higher power factor. Thus, in this paper, the performance of the different power factor correction ( PFC ) topologies implemented [...] Read more.

The spread of the 5G technology in the telecom power applications increased the need to supply high power density with higher efficiency and higher power factor. Thus, in this paper, the performance of the different power factor correction ( PFC ) topologies implemented to work with high power density telecom power applications are investigated. Two topologies, namely the conventional and the bridge interleaved continues-current-conduction mode (CCM) PFC boost converters are designed. Selection methodology of the switching elements, the manufacturing of the boost inductors, and the optimal design for the voltage and current control circuits based on the proposed small signal stability modeling are presented. The printed circuit board (PCB) for the two different PFC topologies with a power rating of 2 kW were designed. PSIM simulation and the experiments are used to show the supply current total harmonic distortions (THD), voltage ripples, power efficiency, and the power factor for the different topologies with different loading conditions. Full article

(This article belongs to the Special Issue Design and Analysis of Electrical Machines and Drives)

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9 pages, 46025 KiB

Open AccessArticle

Design of the High-Speed PMSG with Two Different Shaft Material Considering Overhang Effect and Mechanical Characteristics

by Jeong-In Lee, Tae-Kyoung Bang, Hoon-Ki Lee, Jong-Hyeon Woo, Junghyo Nah and Jang-Young Choi

Appl. Sci. 2021, 11(16), 7670; https://doi.org/10.3390/app11167670 - 20 Aug 2021

Cited by 3 | Viewed by 2037

Abstract

In general, high-speed machines should be designed to satisfy electromagnetic and mechanical characteristics. In this study, the design of high-speed permanent magnet synchronous generator with two different shaft materials considering overhang effect and mechanical characteristics was performed. It was confirmed that the leakage [...] Read more.

In general, high-speed machines should be designed to satisfy electromagnetic and mechanical characteristics. In this study, the design of high-speed permanent magnet synchronous generator with two different shaft materials considering overhang effect and mechanical characteristics was performed. It was confirmed that the leakage magnetic flux generated by the two shaft materials electromagnetically affects the high-speed generator. Additionally, it is important to accurately predict the natural frequency mode and critical speed to prevent damage and vibration of the rotating body owing to scattering during high-speed rotation. Therefore, the mechanical characteristics of the designed model were analyzed. In this study, we propose a design method that considers both the electromagnetic effects and mechanical characteristics. Subsequently, verification was performed through experiments and comparisons for the validity and reliability of the proposed design method. Full article

(This article belongs to the Special Issue Design and Analysis of Electrical Machines and Drives)

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18 pages, 11801 KiB

Open AccessFeature PaperArticle

Design and Analysis of the 45kW-Class Magnetic Geared Permanent Magnet Synchronous Motor for Traction of Tram Vehicles

by Jae-Hyeon Lim, Geochul Jeong, Hyung-Woo Lee, Jae-Bum Lee, Jong-Seok Lim and Chan-Bae Park

Appl. Sci. 2021, 11(14), 6360; https://doi.org/10.3390/app11146360 - 9 Jul 2021

Cited by 8 | Viewed by 3310

Abstract

The magnetic geared permanent magnet synchronous motor (MG-PMSM) is a PMSM that has two rotors with different rotation speeds and includes the function of magnetic gear. The design studies of the 45kW-class MG-PMSM are conducted for the application of the driving system for [...] Read more.

The magnetic geared permanent magnet synchronous motor (MG-PMSM) is a PMSM that has two rotors with different rotation speeds and includes the function of magnetic gear. The design studies of the 45kW-class MG-PMSM are conducted for the application of the driving system for a tram. In this research, first, to derive the detailed model of the 45kW-class MG-PMSM for the tram, the analysis of the characteristics according to the stator winding method was performed. After selecting the winding method that can reduce the size of the MG-PMSM, two design topologies were applied to determine the number of stator poles, the number of outer rotor pole pieces, and the number of inner rotor poles of the MG-PMSM. A 45kW-class MG-PMSM detailed model was derived by applying a design topology that can minimize the size of the MG-PMSM, and it was confirmed that the required performance is satisfied through electromagnetic characteristics analysis. In addition, the 4.5kW-class small-scaled MG-PMSM prototype with concentrated winding was manufactured to verify the validity of the analytical model, and performance verification was performed. Full article

(This article belongs to the Special Issue Design and Analysis of Electrical Machines and Drives)

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18 pages, 6887 KiB

Open AccessArticle

Design of External Rotor Ferrite-Assisted Synchronous Reluctance Motor for High Power Density

by Md. Zakirul Islam, Seungdeog Choi, Malik E. Elbuluk, Sai Sudheer Reddy Bonthu, Akm Arafat and Jeihoon Baek

Appl. Sci. 2021, 11(7), 3102; https://doi.org/10.3390/app11073102 - 31 Mar 2021

Cited by 5 | Viewed by 3843

Abstract

The rare-earth (RE) permanent magnets (PM) have been increasingly adopted in traction motor application. However, the RE PM is expensive, less abundant, and has cost uncertainties due to limited market suppliers. This paper presents a new design of a RE-free five-phase ferrite permanent [...] Read more.

The rare-earth (RE) permanent magnets (PM) have been increasingly adopted in traction motor application. However, the RE PM is expensive, less abundant, and has cost uncertainties due to limited market suppliers. This paper presents a new design of a RE-free five-phase ferrite permanent magnet-assisted synchronous reluctance motor (Fe-PMaSynRM) with the external rotor architecture with a high saliency ratio. In such architecture, the low magnetic coercivity and demagnetization risk of the ferrite PM is the challenge. This limits the number of flux barriers, saliency ratio, and reluctance torque. A precise analytical design procedure of rotor and stator configuration is presented with differential evolution numerical optimizations by utilizing a lumped parameter model. A 3.7 kW prototype is fabricated to validate the proposed idea. Full article

(This article belongs to the Special Issue Design and Analysis of Electrical Machines and Drives)

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16 pages, 16906 KiB

Open AccessFeature PaperArticle

Movement Control Method of Magnetic Levitation System Using Eccentricity of Non-Contact Position Sensor

by Jong Suk Lim and Hyung-Woo Lee

Appl. Sci. 2021, 11(5), 2396; https://doi.org/10.3390/app11052396 - 8 Mar 2021

Cited by 2 | Viewed by 3556

Abstract

This paper presents a method of utilizing a non-contact position sensor for the tilting and movement control of a rotor in a rotary magnetic levitation motor system. This system has been studied with the aim of having a relatively simple and highly clean [...] Read more.

This paper presents a method of utilizing a non-contact position sensor for the tilting and movement control of a rotor in a rotary magnetic levitation motor system. This system has been studied with the aim of having a relatively simple and highly clean alternative application compared to the spin coater used in the photoresist coating process in the semiconductor wafer process. To eliminate system wear and dust problems, a shaft-and-bearing-free magnetic levitation motor system was designed and a minimal non-contact position sensor was placed. An algorithm capable of preventing derailment and precise movement control by applying only control without additional mechanical devices to this magnetic levitation system was proposed. The proposed algorithm was verified through simulations and experiments, and the validity of the algorithm was verified by deriving a precision control result suitable for the movement control command in units of 0.1 mm at 50 rpm rotation drive. Full article

(This article belongs to the Special Issue Design and Analysis of Electrical Machines and Drives)

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27 pages, 84320 KiB

Open AccessArticle

Optimal IP Current Controller Design Based on Small Signal Stability for THD Reduction of a High-Power-Density PFC Boost Converter

by Ahmed H. Okilly, Hojin Jeong and Jeihoon Baek

Appl. Sci. 2021, 11(2), 539; https://doi.org/10.3390/app11020539 - 7 Jan 2021

Cited by 3 | Viewed by 4682

Abstract

This paper presents an optimal design for the inner current-control loop of the continuous current conduction mode (CCM) power factor correction (PFC) stage, which can be used as the front stage of the two-stage AC/DC telecom power supply. The conventional single-phase CCM-PFC boost [...] Read more.

This paper presents an optimal design for the inner current-control loop of the continuous current conduction mode (CCM) power factor correction (PFC) stage, which can be used as the front stage of the two-stage AC/DC telecom power supply. The conventional single-phase CCM-PFC boost converter is implemented with proportional–integral (PI) controllers in both the voltage and current-control loops to regulate the output DC voltage to the specified value and to ensure the input current follows the input voltage, which offers a converter with a high-power factor (PF) and low current total harmonic distortion (THD). However, due to the slow dynamic response of the PI controller at the zero-crossing point of the input supply current, the input current cannot fully follow the input voltage, which leads to high THD. In this paper, we investigate a digitally controlled PFC converter with an optimally designed inner current-control loop using a doubly-fed control loops integral-proportional (IP) controller to reduce the THD and to offer an input current with a unity PF. For the economic design of a digitally controlled PFC converter, two isolated AC and DC voltage sensors are designed for interfacing with the microcontroller unit (MCU). PSIM software as well as experimental prototype was used to test the converter performance using the proposed designed current controllers and isolated voltage sensors. We achieved a high-power-density, digitally controlled, telecom PFC stage with a power factor more than 99% and THD of about 5.50%. Full article

(This article belongs to the Special Issue Design and Analysis of Electrical Machines and Drives)

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17 pages, 4893 KiB

Open AccessArticle

Model Predictive Control Method Based on Deterministic Reference Voltage for Single-Phase Three-Level NPC Converters

by Eun-Su Jun, Minh Hoang Nguyen and Sangshin Kwak

Appl. Sci. 2020, 10(24), 8840; https://doi.org/10.3390/app10248840 - 10 Dec 2020

Cited by 4 | Viewed by 2133

Abstract

When single-phase three-level neutral-point-clamped (NPC) converters operate, there are two main control objectives that need to be met for correct operation. First, the ac source current must be controlled to be sinusoidal. Second, the dc capacitor voltages must be balanced. In original model [...] Read more.

When single-phase three-level neutral-point-clamped (NPC) converters operate, there are two main control objectives that need to be met for correct operation. First, the ac source current must be controlled to be sinusoidal. Second, the dc capacitor voltages must be balanced. In original model predictive control (MPC) methods for NPC converters, an optimization process involving an empirical weighting factor design is required to meet both of these objectives simultaneously. This study proposes an MPC approach developed for single-phase three-level NPC converters to meet these objectives using a single reference voltage consisting of a difference-mode term and a common-mode term in each phase. The difference-mode term and the common-mode term are responsible for sinusoidal ac source current synthesis and dc capacitor voltage balancing, respectively. Then, a single cost function compares the adjusted reference voltage with possible voltage candidates to select an optimal switching state, resulting in the smallest cost function value. Different from the conventional MPC method, the proposed approach avoids the selection of weighting factors and the attendance of various control objectives. Thanks to the deterministic approach, the proposed MPC method is straightforward to implement and maintain fast transient performance while guaranteeing the control objectives. Finally, the effectiveness and feasibility of the proposed approach for single-phase three-level NPC are verified through comprehensive experimental results. Full article

(This article belongs to the Special Issue Design and Analysis of Electrical Machines and Drives)

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16 pages, 6582 KiB

Open AccessFeature PaperArticle

Design of Three-Phase V-Shaped Interior Permanent Magnet Synchronous Motor for Air Conditioning Compressor of Electric Vehicle

by Hojin Jeong and Jeihoon Baek

Appl. Sci. 2020, 10(24), 8785; https://doi.org/10.3390/app10248785 - 8 Dec 2020

Cited by 2 | Viewed by 3210

Abstract

Air conditioning system of electric vehicles has new change as the internal combustion engine is being replaced with electrified AC motor. With large amount of batteries installed at the bottom of frame, the conventional compressor, which is belt-driven, can be removed, and another [...] Read more.

Air conditioning system of electric vehicles has new change as the internal combustion engine is being replaced with electrified AC motor. With large amount of batteries installed at the bottom of frame, the conventional compressor, which is belt-driven, can be removed, and another AC motor can play the role for air conditioning in electric vehicles. From this change, the system efficiency would be improved since it is possible to control the electrified compressor independently from traction system in contrast with the belt-driven compressor. As a result, by applying the electrified compressor for air conditioning system, the whole system can achieve better efficiency and longer driving distance, which is most important in electric vehicles. In this paper, 3-phase interior permanent magnet synchronous motor (IPMSM) was designed using lumped-parameter model and finite element method. Full article

(This article belongs to the Special Issue Design and Analysis of Electrical Machines and Drives)

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15 pages, 8227 KiB

Open AccessFeature PaperArticle

A Current Control Algorithm to Improve Command Tracking Performance and Resilience of a Grid-Connected Inverter

by Horyeong Jeong, Jong Hyuk Choi and Jae Suk Lee

Appl. Sci. 2020, 10(23), 8642; https://doi.org/10.3390/app10238642 - 3 Dec 2020

Viewed by 2039

Abstract

This paper presents a stationary reference frame grid current control algorithm for a grid-connected inverter (GCI) to improve command tracking performance and resilience in response to disturbances, i.e., a grid voltage incident in a GCI current control system. In the proposed algorithm, disturbance [...] Read more.

This paper presents a stationary reference frame grid current control algorithm for a grid-connected inverter (GCI) to improve command tracking performance and resilience in response to disturbances, i.e., a grid voltage incident in a GCI current control system. In the proposed algorithm, disturbance rejection is applied to reduce the overcurrent at the GCI in response to a grid fault. Disturbances to the GCI current control system are estimated using a grid current observer, and the estimate applied to the grid current controller to activate the disturbance rejection. The stationary reference frame current of a GCI system is also controlled to avoid cross-coupling issues at a synchronous reference frame model, reference transformation and dependency to phase locked loop (PLL) performance. However, the phase lead or lag and steady-state response error, which are drawbacks of AC signal control based on stationary reference frame proportional-integral (PI) controller, must be eliminated in order to secure competition with the synchronous reference PI (SRFPI) controller that was mainly used in the GCI system. Hence, to compensate for command tracking the AC current, such as steady-state response error and phase lead or lag, command feedforward control is applied in the proposed control system. The theory behind the proposed GCI current control algorithm is analyzed, and the proposed algorithm is tested via simulation and experimentation. Full article

(This article belongs to the Special Issue Design and Analysis of Electrical Machines and Drives)

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14 pages, 4967 KiB

Open AccessArticle

Frequency-Domain Characteristics of Series DC Arcs in Photovoltaic Systems with Voltage-Source Inverters

by Jae-Chang Kim and Sang-Shin Kwak

Appl. Sci. 2020, 10(22), 8042; https://doi.org/10.3390/app10228042 - 13 Nov 2020

Cited by 12 | Viewed by 2268

Abstract

In this study, the frequency characteristics of series DC arcs are analyzed according to the types of frequency fluctuations caused by inverters in photovoltaic (PV) systems. These frequency fluctuation types used in analysis include centralized frequency fluctuations by three-phase inverter, spread frequency fluctuations [...] Read more.

In this study, the frequency characteristics of series DC arcs are analyzed according to the types of frequency fluctuations caused by inverters in photovoltaic (PV) systems. These frequency fluctuation types used in analysis include centralized frequency fluctuations by three-phase inverter, spread frequency fluctuations by three-phase inverter, and centralized frequency fluctuations by single-phase inverter. To collect arc current data, the frequency fluctuations are generated by inverters in the arc-generating circuit, designed by referring to UL1699B, and the arcs are generated by separating the arc rods of the arc generator. The frequency analysis of the arc current data, collected using an oscilloscope, is conducted using MATLAB. From the results of the frequency characteristics analysis, it is confirmed that the frequencies in the range from 5 to 40 kHz increase after arc generation regardless of the type of frequency fluctuation. In addition, the smaller the current, the greater the increase in frequencies between 5 and 40 kHz after arc generation. Further, in case of arc currents with centralized frequency fluctuations, for larger switching frequencies, the 5 to 40 kHz components increase to a greater extent after arcing. Full article

(This article belongs to the Special Issue Design and Analysis of Electrical Machines and Drives)

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