Jun-hyeok Song

Jong-myeong Kim

Gun Shin

Jong-geun Cha

The Korea University Power Electronics Lab (KUPEL) focuses on motor drives and power electronics for E-mobility systems. Main research areas include motor and inverter control, wireless power transfer, and battery charging systems.

고려대학교 전력전자연구실(KUPEL)은 E-모빌리티 시스템용 모터 구동 및 전력 전자 연구에 중점을 둔다. 주요 연구 분야는 모터 및 인버터 제어, 무선 전력 전송, 배터리 충전 시스템이다.

Fault-tolerant control for one-phase current sensor fault in open-end winding PMSM fed by dual inverter with a common DC bus

A Novel ZSC Regulator with Third-harmonic BackEMF Estimation for OW-PMSM fed by Dual Inverter with a Common DC-bus

Q-MRAS Based I-F Startup for Model Predictive Current Controlled Sensorless SPMSM Drive

Detection of Trailing Edge Demagnetization in Surface PM Synchronous Machines Based on High Frequency Equivalent Impedance

PWM Strategy in OVM and Six-step Regions for Open-end Winding PMSM Fed by a Dual Inverter with a Common DC Bus

Dual MRAS for Robust Rotor Time Constant Compensation in IFOC IM Drives

Current Measurement Offset Error Compensation for IFOC Induction Motor Drives

Simple Discontinuous Pulse-Width Modulation Scheme for the Loss Reduction of a Dual Inverter Fed an Open-end Winding Induction Motor

Reactive-power-based Robust MTPA Control for v/f Scalar-controlled Induction Motor Drives

Inverter-embedded Partial Discharge Testing for Reliability Enhancement of Stator Winding Insulation in Low Voltage Machines

Model Predictive Current Control with Online Parameter Estimation for Synchronous Reluctance Machine Controlled by High-Frequency Signal Injection Position-Sensorless

Improved EEMF-Based Position Sensorless Control for Non-Sinusoidal Back-EMF PMSMs

Current Measurement Offset Error Compensation in Vector-controlled SPMSM Drive Systems

MTPA Control Strategy Based on Signal Injection for V/f Scalar-Controlled Surface Permanent Magnet Synchronous Machine Drives

A Rotating Restart Method for Scalar (v/f) Controlled Synchronous Reluctance Machine Drives Using a Single DC-Link Current Sensor

A Sinusoidal Current Control Strategy Based on Harmonic Voltage Injection for Harmonic Loss Reduction of PMSMs with Non-Sinusoidal Back-EMF

Restart Strategy for Scalar (V/f) Controlled Synchronous Reluctance Machine Driving a High Inertia Load

Universal Restart Strategy for Scalar (V/f) Controlled Induction Machines

Universal Restart Strategy for High-Inertia Scalar-Controlled PMSM Drives

Receivers for Multifrequency Wireless Power Transfer: Design for Minimum Interference

Reflexive Field Containment in Dynamic Inductive Power Transfer Systems

Multifrequency Inductive Power Transfer

표면 부착형 동기 전동기 벡터 제어에서의 외란 관측기 기반 전류 측정 오프셋 오차 보상 방법

V/f 스칼라 제어 영구자석 동기 전동기의 안정적 초기 구동 기법

Fault Control Strategy for Torque Ripple Reduction in Single-Phase Open Fault of OW-PMSM Fed by a Dual Inverter with a Common DC Bus

Online Compensation Strategy for Current Sensor Scaling Errors in Induction Motor Drive Systems

Enhanced Efficiency Inverter with Winding Changeover Circuit for Ultra High-Speed SPMSMs in Fuel-Cell Electric Vehicles

I-F Startup with Reactive Power-based MRAS for Model Predictive Current Controlled SPMSM Drive

A Novel ZSC Suppression Strategy with Third-harmonic Back-EMF Estimation for OW-PMSM fed by Dual Inverter with a Common DC-bus

Detection of Trailing Edge Demagnetization in Surface PM Synchronous Machines based on High Frequency Equivalent Impedance

Improved Q-MRAS Based Online Rotor Time Constant Compensation for IFOC Controlled Induction Motor Drive

Discontinuous PWM Scheme for an Open-end Winding Induction Motor Drives Fed by Dual Inverter

Current Measurement Offset Error Compensation for Indirect Field-Oriented Controlled Induction Motor Drives

Parameter-Free Predictive Current Control for Synchronous Machine Controlled by High-Frequency Signal Injection Sensorless

Maximum Torque per Ampere (MTPA) Control for Scalar v/f Controlled SPMSM Drives

Restart Strategy for Scalar Controlled Synchronous Reluctance Machine Driving a High-Inertia Load with a Single DC-link Current Sensor

Restart Strategy for Synchronous Reluctance Machine Driving a High Inertia Load

A universal restart strategy for induction machines

A universal restart strategy for permanent magnet synchronous machines

Field containment in dynamic wireless charging systems through source-reciever interaction

Inductive power transfer by means of multiple frequencies in the magnetic link

Comprehensive smart-clamp strategy for inverter systems

System and method for estimating rotor sensor offset

Sensor-less Control of an electric motor

Restart strategy for synchronous reluctance machines

Air Conditioning System and Method for Controlling Operation Thereof

Kibok Lee

We present a new topology appropriate for “dynamic” wireless charging. Possible applications include charging of electric vehicles or robots moving in a large, predesignated area. We propose a system with a transmitter made from multiple coils commensurable with the moving receiver(s), and powered by a single inverter. The proposed system uses the reactance reflected by the receiver to automatically increase the field strength in coupled portions of the transmitter-receiver system, thus allowing efficient power transfer and adherence to electromagnetic field emission standards without complex shielding circuits, switches, electronics, and communication. The power transfer is at its peak when the transmitting and receiving coils approach their maximum coupling (as defined by the geometrical constraints of the system), resulting in improved system-level efficiency. The presented analysis is supported with …

Reflexive field containment in dynamic inductive power transfer systems

Inductive (or wireless) power transfer is proving to be an effective way to deliver power over short distances in a wide range of applications. Frequently, there is a need to deliver power from a single transmitter to multiple mutually coupled receivers. In this paper, we quantify how the power delivered to each receiver is affected due to the resonant frequency shift resulting from receiver mutual coupling. We show that the effect on power delivered is quite severe, especially in high-quality-factor systems. We develop the mathematical framework and demonstrate experimentally that the problem disappears if each receiver is tuned at one of the frequencies emitted by a single transmitter. We adopt the concept of frequency traps as a method to completely decouple the receivers.

This paper presents a generalized analysis of an inductive power transfer system where multiple frequencies are used to transfer power through the magnetic link. Specifically, we consider a system that amplifies both the fundamental and the third harmonic generated by a full-bridge inverter in order to transfer power to a receiver at both frequencies. The system is analyzed in a generalized manner, by looking at the transconductance function at the transmitter and the receiver for each of the harmonics. Using this approach, the emitted field strength, inverter losses, combined transmitter and receiver coil conduction losses, and VA ratings are compared to a reference single-frequency system. The analysis shows that the dual-frequency system can outperform the single-frequency equivalent for all metrics considered; however, in practice, a tradeoff between the performance criteria is necessary, since the optimal …

In permanent magnet synchronous machine design, a limited number of stator and rotor slots distorts the air-gap flux distribution and its effective length. It causes machine parameters to vary with the rotor position. The rotor flux linkage harmonics introduce nonsinusoidal back-EMF, which causes current harmonics when conventional PI current controller is adopted. Those machines suffer from high-frequency torque ripple due to air-gap flux harmonics in low-speed region. However, in high-speed region, where the torque ripple is filtered out by the mechanical system, the torque ripple may be disregarded. In this case, torque-ripple suppression methods and the associated harmonic current components generate losses. Therefore, a sinusoidal current control is required to reduce the undesired harmonic losses. In this manner, this article focuses on the sinusoidal current control strategy based on harmonic voltage …

A sinusoidal current control strategy based on harmonic voltage injection for harmonic loss reduction of PMSMs with non-sinusoidal back-EMF

In many industrial settings, momentary power disruptions commonly occur, resulting in tripping of large electric machines, which then have to be brought to zero speed before the machine can be restarted. This can result in frequent interruptions in an industrial process, which can have negative effects on productivity. A more practical approach would restart the machine back to the original speed as soon as power is restored, not having to wait for the machine to be at a standstill. This concept is known as flying restart. In this paper, we propose an approach to implement the flying restart for permanent magnet synchronous machines (PMSM) by using an identification algorithm that determines the speed and position of the machine back-electromotive force so that the correct voltage vector can be applied, thus minimizing the inrush current during the restart. The novelty of the proposed method is that its …

Universal restart strategy for high-inertia scalar-controlled PMSM drives

This article proposes a new maximum torque per ampere (MTPA) control strategy for an induction motor (IM) controlled by the scalar ( v / f ) method. In scalar control, constant air-gap flux control is generally adopted for IM drives to provide the same torque capability in all operating ranges. However, this control method results in poor motor efficiency due to excessive stator current at light loads. This work proposes a new MTPA control method to minimize the stator current amplitude based on reactive power without measuring the rotor mechanical speed, resulting in improved system efficiency at light loads. In addition, this method proposes an online machine parameter compensation method. Thus, this proposed method is robust to parameter variations. Simulation and experimental results are provided to verify the performance of this MTPA control strategy.

Reactive-power-based robust MTPA control for v/f scalar-controlled induction motor drives

Current measurement offset errors occur in current sensors and related circuits, because of various factors, such as thermal drift, aging, and nonlinearity. The current offset error results in undesired torque ripples, which deteriorate the speed and torque control performances of vector-controlled drive systems. This study proposes an online current measurement offset error compensator for vector-controlled surface permanent magnet synchronous motor (SPMSM) drive systems. The proposed compensator requires only phase current sensors and no additional hardware. This method is applicable for all systems using two and three phase current sensors. The current offset error is estimated using the motor parameters, stator current, and command voltage in the stationary reference frame. This scheme can continuously adjust the current offset during motor operation. In addition, this study analyzes the effect of …

Current measurement offset error compensation in vector-controlled SPMSM drive systems

This paper presents a universal flying restart strategy for scalar ( V/f ) controlled induction machines. The proposed method performs a frequency search to estimate the rotor speed, and applies the correct frequency and voltage to minimize the inrush current during the restart. This method uses the measured phase current and the motor nameplate parameters, thus making the approach ideal for scalar-controlled motor drives. In addition, the restart algorithm provides controllable restart dynamics, independent of the motor parameters. The main advantages of this method include simple and cost effective implementation without the need for additional sensors, and controllable restart dynamics independent of the motor parameters. Beyond the development of the algorithm, we consider implementation issues to provide a general guideline for the application of the developed algorithm.

Universal restart strategy for scalar (V/f) controlled induction machines

This work investigates maximum efficiency control strategies of permanent magnet (PM) traction machine drives that are adopted in General Motors (GM) hybrid and electric vehicles. First, three different current vector control techniques, Maximum Torque Per Ampere (MTPA), Maximum Torque Per Motor Loss (MTPML), and Maximum Torque Per System Loss (MTPSL), are presented to identify the most attractive control strategy for a PM traction machine drive that is being used in a production vehicle. This comparison will show the drive system efficiency and the current vector trajectory for the three different control strategies, providing valuable experimental data to help researchers optimize the operating point efficiency. In addition, a six-step mode of inverter control is evaluated to enhance the drive efficiency and performance under the dc bus voltage constraint in the flux weakening region. Extensive experimental …

Maximum efficiency control strategy of PM traction machine drives in GM hybrid and electric vehicles

Partial discharge (PD) due to high dv/dt pulsewidth modulation has been identified as one of the leading causes of insulation failure in low voltage (LV) variable frequency drive (VFD) fed motors with random wound stator windings. With the recent increase in electrical stress with faster risetime wide bandgap power semiconductor devices and higher dc link voltage for higher efficiency and power density of the system, PD-induced insulation failures are expected to increase. Since LV motor insulation is not resistant to PD, an increasing number of VFD motors are being qualified for PD-free operation. However, the PD inception voltage of qualified motors decreases with insulation aging making LV motors susceptible to failure. In this article, an offline standstill test method is proposed for automated inverter-embedded PD testing under impulse excitation. The main concept is to perform the impulse PD test using the …

Inverter-embedded partial discharge testing for reliability enhancement of stator winding insulation in low voltage machines

This paper presents a simple discontinuous pulse width modulation (DPWM) switching scheme to reduce the switching loss of a single DC-link dual two-level inverter fed an open-end winding (OW) induction motor (IM). The dual inverter system is attractive in many applications due to higher DC-link voltage utilization. Additionally, the OW motor has the potential fault-tolerant capability. However, the use of the dual inverter results in reduced system efficiency due to increased power losses in the inverter. Moreover, an OW motor inherently suffers from a zero-sequence current (ZSC) issue because the open neutral point of the stator windings provides the ZSC path. The ZSC causes negative effects in the system, such as an additional power loss and total harmonic distortion (THD). Thus, this work proposes an optimal DPWM scheme to reduce the inverter loss while suppressing the ZSC. Additionally, this work …

Simple discontinuous pulse-width modulation scheme for the loss reduction of a dual inverter fed an open-end winding induction motor

Accurate machine parameters and rotor position information are essential in vector-controlled motor drive systems. However, machine parameter variations by various factors such as the current and the temperature degrade the performance of vector control. Also, a position sensor such as an encoder and a resolver increases the drive system cost. This paper proposes model predictive current control (MPCC) with the online parameter estimation for synchronous reluctance machines controlled by a high-frequency signal injection position-sensorless method. This approach removes the need for accurate knowledge about the system and eliminates the need for the position sensor. The proposed method adopts a recursive least-square (RLS) to estimate the electrical machine parameters in real-time. The estimated parameters are used for the deadbeat continuous control set (CCS) MPCC and the position …

Model predictive current control with online parameter estimation for synchronous reluctance machine controlled by high-frequency signal injection position-sensorless

In this paper, a new maximum torque per ampere (MTPA) control method for surface permanent magnet synchronous motors (SPMSMs) controlled by the scalar control (v/f) method is proposed. The scalar control is a sensorless method that controls only the magnitude and the frequency of the stator voltage vector without the information of the rotor position. This method suggests the injection of the high frequency voltage signal in the stator current vector reference frame, which can be calculated from the measured phase currents, to avoid the use of rotor position information. In addition, this method adjusts only the magnitude of the stator voltage to minimize the stator current based on the calculated input power. Another merit of this method is the robustness of the MTPA control to machine parameter errors or variations. With this proposed method, the stator current can be minimized in the whole speed-torque range …

MTPA control strategy based on signal injection for V/f scalar-controlled surface permanent magnet synchronous machine drives

In this paper we explore the concept of transmitting and receiving power wirelessly at multiple frequencies. This proposed frequency multiplex is achieved by using multi-resonant tanks at the transmitter and receiver to amplify and extract power at multiple frequencies. Frequency multiplexed IPT system is a new concept that has numerous advantages over the state of the art: (1) low switching frequency converters can be used to drive high-frequency IPT systems, (2) emission standards may become easier to meet by spreading the power transfer over a spectrum of frequencies, (3) single-frequency receivers tuned to different frequencies can be charged simultaneously even though their coils are at close proximity and mutually coupled, etc. In this paper we develop the theory of source and receiver resonant tank design, and present the complete methodology for determining the system quality factor, effective …

BACKGROUND 0003 BLDC motors are widely used not only in home appliance products such as a refrigerator, an air conditioning system, and the like, but also in information processing sys tem. Such as a floppy disk drive. A separate detection device is provided in a BLDC motor in order to detect the revolution speed, the location of rotor, and the like. However, a sensor less BLDC motor does not need this detection device. 0004. A typical sensorless BLDC motor may include three U, V, and W coils 11, 12, 13 respectively and a rotor 14 as shown in FIG. 1. Furthermore, there are two types of methods for controlling the revolution speed of Such a motor, such as 120-degree conduction method and 180-degree conduction

Apparatus and method for controlling a bldc motor

This paper presents a rotating restart method for v/f scalar controlled Synchronous Reluctance Machines (SynRMs) using a single DC-link current sensor. In such a case, the initial rotor position and speed are required to restart the machine due to the absence of a position sensor. The method proposes to inject three active voltage vectors in the stationary reference frame to induce the phase currents required for estimating the rotor position and speed. In addition, the phase current reconstruction method is proposed to reduce the distortion of the measured phase currents caused by adopting a single DC-link current sensor and to consequently enhance the rotor position estimation accuracy. With the proposed method, the appropriate voltage vector can be applied to the machine, thus minimizing the inrush current during the restart. Furthermore, the proposed method only requires the machine parameters on the …

A Rotating restart method for scalar (v/f) controlled synchronous reluctance machine drives using a single DC-Link current sensor

This letter presents a fault-tolerant control (FTC) for a one-phase current sensor failure in the open-ended winding permanent magnet synchronous motor (PMSM) fed by the dual inverter with a common dc bus. While many FTC strategies for stator winding and inverter leg faults have been researched, an FTC for one-phase current sensor fault has not yet been proposed. Unlike a single inverter, the dual inverter with a common dc bus needs three-phase current measurement due to the flow of zero-sequence current (ZSC). A one-phase current sensor fault can result in immediate system shutdown or severe degradation in control performance. This study proposes a method for estimating the one-phase current using the currents from the other two phases. Both the FTC and the ZSC control can be implemented in the presence of a one-phase current sensor fault. Experimental results are provided to validate the …

This study proposes a novel pulsewidth modulation (PWM) strategy in high modulation index (MI) regions for the open-end winding permanent magnet synchronous motor fed by the dual inverter with the common dc bus. The dual-inverter system is getting attention due to the higher voltage utilization and the potential fault-tolerant capability. However, the dual-inverter system inherently suffers from the zero-sequence current (ZSC) flowing due to the opened neutral point of the stator windings and the common dc bus. This ZSC causes negative effects, such as power loss and torque ripple. Various PWM schemes have been proposed to suppress the ZSC. However, the conventional methods focus on a linear MI region and have performance degradation due to the limited voltage modulation margin. This study proposes simple PWM schemes for the ZSC control in the overmodulation and six-step regions. The …

PWM strategy in OVM and six-step regions for open-end winding PMSM fed by a dual inverter with a common DC bus

This paper presents a new topology appropriate for dynamic wireless charging of electric vehicles. We propose a source coil made from multiple lumped coils powered by a single inverter, with the receiver coil mounted on the vehicle. The proposed system uses the reflected reactance from the receiver to automatically limit the field strength in uncoupled portions of the source-receiver system, thus allowing the system to more easily meet the electromagnetic field emission standards without complex shielding circuits, switches, electronics and communication systems. The power transfer is at its peak when the source-receiver coils pair is strongly coupled resulting in improved system-level efficiency. The analysis is supported by simulation and experiments.

In vector control, the accuracy of the current measurement is crucial for ensuring good control performance. However, current measurement offset error is caused by various reasons in the current sensors, the op-amplifiers, and the A/D conversion circuits, such as thermal drift and nonlinearity. The measurement offset error results in undesired current ripples, which deteriorates the speed and torque control performance of the vector-controlled drive systems. This paper proposes the PI-type observer-based current offset error compensation method for the induction motor (IM). The proposed PI-type observer can estimate the DC offset error during the motor operation, which is designed in the stationary reference frame. This study analyzes the effect of the parameter mismatch and confirms the robustness of the parameter mismatch. Simulation and experimental results are provided to verify the performance of the …

Power Electronics Lab.

교수님 소개

이기복

연구실 소개

연구실 키워드

알럼나이가 간 회사

연구실 지원 방법

대우 조건

연도별 논문 인용수

저널 & 학회 논문 출판 수

연구실 논문 목록

Fault-tolerant control for one-phase current sensor fault in open-end winding PMSM fed by dual inverter with a common DC bus

A Novel ZSC Regulator with Third-harmonic BackEMF Estimation for OW-PMSM fed by Dual Inverter with a Common DC-bus

Q-MRAS Based I-F Startup for Model Predictive Current Controlled Sensorless SPMSM Drive

연구실 보유 특허

대학별 입시끈

우리 연구실 모집

교수님 소개

이기복

연구실 키워드

알럼나이가 간 회사

연구실 지원 방법

대우 조건

연도별 논문 인용수

저널 & 학회 논문 출판 수

연구실 논문 목록

Fault-tolerant control for one-phase current sensor fault in open-end winding PMSM fed by dual inverter with a common DC bus

A Novel ZSC Regulator with Third-harmonic BackEMF Estimation for OW-PMSM fed by Dual Inverter with a Common DC-bus

Q-MRAS Based I-F Startup for Model Predictive Current Controlled Sensorless SPMSM Drive

연구실 보유 특허

최근 3년간 연구실적 높은 연구실

대학별 입시끈

우리 연구실 모집