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14 pages, 5790 KiB

Open AccessArticle

Accuracy Improvement in Resolver Offset Detection Based on Angle Tracking Observer with Coordinate Transformation

by Mun-Hong Kim and Do-Yun Kim

Electronics 2021, 10(14), 1643; https://doi.org/10.3390/electronics10141643 - 10 Jul 2021

Cited by 1 | Viewed by 4003

Abstract

It is necessary to obtain the rotor position of the Interior Permanent Magnet Synchronous Motor (IPMSM) for instantaneous torque control in an electric vehicle system. A resolver is mostly used as a rotor position sensor, each motor has a resolver offset according to [...] Read more.

It is necessary to obtain the rotor position of the Interior Permanent Magnet Synchronous Motor (IPMSM) for instantaneous torque control in an electric vehicle system. A resolver is mostly used as a rotor position sensor, each motor has a resolver offset according to the fit tolerance of the resolver pressed into the rotor shaft when the motor is manufactured. This resolver offset is having a huge effect on IPMSM output characteristics. Therefore, resolver offset detection equipment with a method for high precision of detection is required in production lines in order to make uniform characteristics of IPMSM. It is also necessary to have robust performance in many different kinds of the noise of equipment in the production line. This paper presents a highly precise Resolver to Digital Converter (RDC) that is implemented with LabVIEW of National Instruments and a resolver offset detecting method that has the robust performance to noise based on coordinate transformation algorithm. Experiments with and without the proposed method were performed and a comparative analysis is conducted to test the validity. Full article

(This article belongs to the Special Issue State-of-the-art Power Electronics in Korea)

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14 pages, 5723 KiB

Open AccessArticle

A New SOC Estimation for LFP Batteries: Application in a 10 Ah Cell (HW 38120 L/S) as a Hysteresis Case Study

by Younghwi Ko and Woojin Choi

Electronics 2021, 10(6), 705; https://doi.org/10.3390/electronics10060705 - 17 Mar 2021

Cited by 22 | Viewed by 5893

Abstract

An accurate state of charge (SOC) estimation of the lithium iron phosphate battery (LiFePO₄) is one of the most important functions for the battery management system (BMS) for electric vehicles (EVs) and energy storage systems (ESSs). However, an accurate estimation of [...] Read more.

An accurate state of charge (SOC) estimation of the lithium iron phosphate battery (LiFePO₄) is one of the most important functions for the battery management system (BMS) for electric vehicles (EVs) and energy storage systems (ESSs). However, an accurate estimation of the SOC of LiFePO₄ is challenging due to the hysteresis phenomenon occurring during the charge and discharge. Therefore, an accurate modeling of the hysteresis phenomenon is essential for reliable SOC estimation. The conventional hysteresis modeling methods, such as one-state hysteresis modeling and parallelogram modeling, are not good enough to achieve high-accuracy SOC estimation due to their errors in the approximation of the hysteresis contour. This paper proposes a novel method for accurate hysteresis modeling, which can provide a significant improvement in terms of the accuracy of the SOC estimation compared with the conventional methods. The SOC estimation is performed by using an extended Kalman filter (EKF) and the parameters of the battery are estimated by using auto regressive exogenous (ARX) model and the recursive least square (RLS) filter. The experimental results with the conventional and proposed methods are compared to show the superiority of the proposed method. Full article

(This article belongs to the Special Issue State-of-the-art Power Electronics in Korea)

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12 pages, 5246 KiB

Open AccessArticle

Accuracy Improvement of Stator Inductance Identification Method Based on Low-Frequency Current Injection for Three-Level NPC Inverter-Fed IM Drives in Locked-Rotor Standstill Condition

by Yerganat Khojakhan, Kyoung-Min Choo, Junsin Yi and Chung-Yuen Won

Electronics 2021, 10(4), 488; https://doi.org/10.3390/electronics10040488 - 19 Feb 2021

Viewed by 1837

Abstract

In this paper, a stator inductance identification process is proposed. The process is based on a three-level neutral-point-clamped (NPC) inverter-fed induction motor (IM) drive with a standstill condition. Previously, a low-speed alternating current (AC) injection test for stator inductance identification was proposed to [...] Read more.

In this paper, a stator inductance identification process is proposed. The process is based on a three-level neutral-point-clamped (NPC) inverter-fed induction motor (IM) drive with a standstill condition. Previously, a low-speed alternating current (AC) injection test for stator inductance identification was proposed to overcome practical problems in conventional identification methods for three-level NPC inverter-based IM drives. However, the low-speed AC injection test-based identification method has some problems if a heavy load or mechanical brake is connected, as these can forcibly bring the rotor to a standstill during parameter identification. Since this low-speed testing-based identification assumes the motor torque is considerably lower in low-speed operations, some inaccuracy is inevitable in this kind of standstill condition. In this paper, the proposed current injection speed generator is based on the previously studied low-speed test-based stator inductance identification method, but the proposed approach gives more accurate estimates under the aforementioned standstill conditions. The proposed method regulates the speed for sinusoidal low-frequency AC injection on the basis of the instantaneous reactive and air-gap active power ratio. This proposed stator inductance identification method is more accurate than conventional fixed low-frequency AC signal injection identification method for three-level NPC inverter-fed IM drive systems with a locked-rotor standstill condition. The proposed method’s accuracy and reliability were verified by simulation and experiment using an 18.5 kW induction motor. Full article

(This article belongs to the Special Issue State-of-the-art Power Electronics in Korea)

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17 pages, 8615 KiB

Open AccessArticle

Improved Finite Set-Predictive Torque Control of PMSM Fed by Indirect Matrix Converter with Discrete Space Vector Modulation

by Ibrahim Mohd Alsofyani, Yeongsu Bak and Kyo-Beum Lee

Electronics 2020, 9(12), 2133; https://doi.org/10.3390/electronics9122133 - 13 Dec 2020

Cited by 5 | Viewed by 1998

Abstract

This study presents finite set-predictive torque control (FS-PTC) with discrete space vector modulation (DSVM) for indirect matrix converter (IMC)-fed permanent magnet synchronous motors (PMSMs). The implementation of FS-PTC with DSVM in an IMC requires high computation time due to the large number of [...] Read more.

This study presents finite set-predictive torque control (FS-PTC) with discrete space vector modulation (DSVM) for indirect matrix converter (IMC)-fed permanent magnet synchronous motors (PMSMs). The implementation of FS-PTC with DSVM in an IMC requires high computation time due to the large number of synthesized voltage vectors (VVs). To reduce computation time caused by considering all VVs, a new preselection strategy is proposed to reduce the computational numerations from 37 to 6 VVs. The proposed algorithm can reduce torque and flux ripples and achieve robust characteristics against parameter variations. Additionally, the increased degree of VVs can improve the correlation between the rectifier and inverter sides of the IMC. The effectiveness of the proposed method is verified by simulation and experimental results. Full article

(This article belongs to the Special Issue State-of-the-art Power Electronics in Korea)

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19 pages, 6400 KiB

Open AccessArticle

Practical Controller Design of Three-Phase Dual Active Bridge Converter for Low Voltage DC Distribution System

by Hyun-jun Choi, Won-bin Lee and Jee-hoon Jung

Electronics 2020, 9(12), 2101; https://doi.org/10.3390/electronics9122101 - 09 Dec 2020

Cited by 4 | Viewed by 4470

Abstract

In a low voltage DC (LVDC) distribution system, isolated bi-directional DC-DC converters are key devices to control power flows. A three-phase dual-active-bridge (3P-DAB) converter is one of the suitable candidates due to inherent soft-switching capability, low conduction loss, and high-power density. However, the [...] Read more.

In a low voltage DC (LVDC) distribution system, isolated bi-directional DC-DC converters are key devices to control power flows. A three-phase dual-active-bridge (3P-DAB) converter is one of the suitable candidates due to inherent soft-switching capability, low conduction loss, and high-power density. However, the 3P-DAB converter requires a well-designed controller due to the influence of the equivalent series resistance (ESR) of an output filter capacitor, degrading the performance of the 3P-DAB converter in terms of high-frequency noise. Unfortunately, there is little research that considers the practical design methodology of the 3P-DAB converter’s controller because of its complexity. In this paper, the influence of the ESR on the 3P-DAB converter is presented. Additionally, the generalized average small-signal model (SSM) of the 3P-DAB converter including the ESR of the capacitive output filter is presented. Based on this model, an extended small-signal model and appropriate controller design guide, and performance comparison are presented based on the frequency domain analysis. Finally, experimental results verify the validity of the proposed controller using a 25 kW prototype 3P-DAB converter. Full article

(This article belongs to the Special Issue State-of-the-art Power Electronics in Korea)

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14 pages, 949 KiB

Open AccessArticle

Investigation of Scale Conversion for Inductive Power Transfer in Series-Series Configuration

by Chanh-Tin Truong and Sung-Jin Choi

Electronics 2020, 9(11), 1851; https://doi.org/10.3390/electronics9111851 - 05 Nov 2020

Cited by 4 | Viewed by 1799

Abstract

Nowadays, inductive wireless power transfer is widely used in various applications over a large power range. However, for high power systems, testing the magnetic coupler implementation often requires too much time, space, and expense for normal laboratory conditions. For such a reason, a [...] Read more.

Nowadays, inductive wireless power transfer is widely used in various applications over a large power range. However, for high power systems, testing the magnetic coupler implementation often requires too much time, space, and expense for normal laboratory conditions. For such a reason, a miniaturized system is a viable alternative to the actual system for a preliminary test of transfer characteristics and control strategy before constructing the full-scaled system. This paper studies the scale conversion rules required for miniaturized coupler design to ensure the scaled and original systems are as equivalent as possible to each other in terms of transfer characteristics. To verify the proposed theory, a 1:15 scaled magnetic coupler was constructed, and its transfer characteristics were compared with the original system. The proposed scaling rules were tested by experiment, and the results agree well with the theoretical analysis and simulation. Full article

(This article belongs to the Special Issue State-of-the-art Power Electronics in Korea)

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16 pages, 4676 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Four-Level Hysteresis-Based DTC for Torque Capability Improvement of IPMSM Fed by Three-Level NPC Inverter

by Samer Saleh Hakami and Kyo-Beum Lee

Electronics 2020, 9(10), 1558; https://doi.org/10.3390/electronics9101558 - 23 Sep 2020

Cited by 19 | Viewed by 2694

Abstract

Direct torque control (DTC) is considered one of the simplest and fastest control strategies used in motor drives. However, it produces large torque and flux ripples. Replacing the conventional two-level hysteresis torque controller (HTC) with a four-level HTC for a three-level neutral-point clamped [...] Read more.

Direct torque control (DTC) is considered one of the simplest and fastest control strategies used in motor drives. However, it produces large torque and flux ripples. Replacing the conventional two-level hysteresis torque controller (HTC) with a four-level HTC for a three-level neutral-point clamped (NPC) inverter can reduce the torque and flux ripples in interior permanent magnet synchronous motor (IPMSM) drives. However, the torque will not be controlled properly within the upper HTC bands when driving the IPMSM in the medium and high-speed regions. This problem causes the stator current to drop, resulting in poor torque control. To resolve this problem, a simple algorithm based on a torque error average calculation is proposed. Firstly, the proposed algorithm reads the information of the calculated torque and the corresponding torque reference to calculate the torque error. Secondly, the average value of torque error is calculated instantaneously as the reference torque changes. Finally, the average value of the torque error is used to indicate the operation of the proposed algorithm without the need for motor speed information. By using the proposed algorithm, the torque can be controlled well in all speed regions, and thus, a better stator current waveform can be obtained. Simulation and experimental results validate the effectiveness of the proposed method. Full article

(This article belongs to the Special Issue State-of-the-art Power Electronics in Korea)

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Review

Jump to: Research

37 pages, 7546 KiB

Open AccessEditor’s ChoiceReview

Enhance Reliability of Semiconductor Devices in Power Converters

by Minh Hoang Nguyen and Sangshin Kwak

Electronics 2020, 9(12), 2068; https://doi.org/10.3390/electronics9122068 - 04 Dec 2020

Cited by 29 | Viewed by 5532

Abstract

As one of the most vulnerable components to temperature and temperature cycling conditions in power electronics converter systems in these application fields as wind power, electric vehicles, drive system, etc., power semiconductor devices draw great concern in terms of reliability. Owing to the [...] Read more.

As one of the most vulnerable components to temperature and temperature cycling conditions in power electronics converter systems in these application fields as wind power, electric vehicles, drive system, etc., power semiconductor devices draw great concern in terms of reliability. Owing to the wide utilization of power semiconductor devices in various power applications, especially insulated gate bipolar transistors (IGBTs), power semiconductor devices have been studied extensively regarding increasing reliability methods. This study comparatively reviews recent advances in the area of reliability research for power semiconductor devices, including condition monitoring (CM), active thermal control (ATC), and remaining useful lifetime (RUL) estimation techniques. Different from previous review studies, this technical review is carried out with the aim of providing a comprehensive overview of the correlation between various enhancing reliability techniques and discussing the corresponding merits and demerits by using 144 related up-to-date papers. The structure and failure mechanism of power semiconductor devices are first investigated. Different failure indicators and recent associated CM techniques are then compared. The ATC approaches following the type of converter systems are further summarized. Furthermore, RUL estimation techniques are surveyed. This paper concludes with summarized challenges for future research opportunities regarding reliability improvement. Full article

(This article belongs to the Special Issue State-of-the-art Power Electronics in Korea)

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