• Title/Summary/Keyword: fundamental frequency component

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Small-Size Induction Machine Equivalent Circuit Including Variable Stray Load and Iron Losses

  • Basic, Mateo;Vukadinovic, Dinko
    • Journal of Electrical Engineering and Technology
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    • v.13 no.4
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    • pp.1604-1613
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    • 2018
  • The paper presents the equivalent circuit of an induction machine (IM) model which includes fundamental stray load and iron losses. The corresponding equivalent resistances are introduced and modeled as variable with respect to the stator frequency and flux. Their computation does not require any tests apart from those imposed by international standards, nor does it involve IM constructional details. In addition, by the convenient positioning of these resistances within the proposed equivalent circuit, the order of the conventional IM model is preserved, thus restraining the inevitable increase of the computational complexity. In this way, a compromise is achieved between the complexity of the analyzed phenomena on the one hand and the model's practicability on the other. The proposed model has been experimentally verified using four IMs of different efficiency class and rotor cage material, all rated 1.5 kW. Besides enabling a quantitative insight into the impact of the stray load and iron losses on the operation of mains-supplied and vector-controlled IMs, the proposed model offers an opportunity to develop advanced vector control algorithms since vector control is based on the fundamental harmonic component of IM variables.

Design of DC Battery Size & Controller for Household Single-Phase ESS-PCS Considering Voltage Drop and DC Link Voltage Ripple (주택용 단상 ESS-PCS의 전압손실과 직류링크 맥동을 고려한 직류측 배터리 사이즈 및 제어기 설계)

  • Kim, Yong-Jung;Lee, Jinsung;Kim, Hyosung
    • The Transactions of the Korean Institute of Power Electronics
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    • v.23 no.2
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    • pp.94-100
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    • 2018
  • Generally, in a single-phase energy storage system (ESS) for households, AC ripple component with twice the fundamental frequency exists inevitably in the DC link voltage of single-phase PCS. In the grid-connected mode of a single-phase inverter, the AC ripple component in the DC link voltage causes low-order harmonics on grid-side current that deteriorates power quality on an AC grid. In this work, a control system adopting a feedforward controller is established to eliminate the AC ripple interference on the DC link side. Optimal battery nominal voltage design method is also proposed by considering the voltage loss and AC ripple voltage on DC link side in a single-phase ESS. Finally, the control system and battery nominal voltage design method are verified through simulations and experiments.

Design of Double-Conversion Down Mixer Using Single Half-LO Frequency at 2.3 GHz (2.3 GHz 대역에서 단일 Half-LO 주파수를 이용한 Double-Conversion Down Mixer 설계)

  • Kim Min-Seok;Moon Ju-Young;Yun Sang-Won
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.17 no.8 s.111
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    • pp.719-724
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    • 2006
  • In this paper, we designed the double conversion down mixer by using Half-LO frequency in 2.3 GHz band. The IF frequency is obtained by supplying two LO frequencies to HEMT in both gate type and resistive type. The proposed mixer uses Half-LO frequency the same way as conventional sub-harmonic mixers. However the proposed one uses fundamental component of Half-LO frequency in first stage instead of using second harmonic components of Half-LO frequency, and the IF frequency is obtained by resistive type mixer in second stage, thereby the proposed mixer can improve linearity in comparison with conventional active mixer. We can verify that the proposed mixer has an conversion loss of 5dBm and IIP3 of 16.25dBm by using 10 dBm Power.

A Study on the Low Power Line Modulation and Power Line Channel Modeling (저압 전력선 통신 변조 기법 및 전력선 채널 특성)

  • Kand Duk-Ha;Heo Yoon-Seok;Cho Ki-Hyung;Lee Dae-Young
    • The Journal of Information Technology
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    • v.5 no.4
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    • pp.1-8
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    • 2002
  • This thesis is about power line communication(PLC) over the low voltage grid. The main advantage with power line communication is the use of an existing infrastructure. The PLC channel can be modeled as having multi-path propagation with frequency-selective fading, typical power lines exhibit signal attenuation increasing with length and frequency. OFDM(Orthogonal Frequency Division Multiplexing) is a modulation technique where multiple low data rate carriers are combined by a transmitter to form a composite high data rate transmission. To implement the multiple carrier scheme using a bank of parallel modulators would not be very efficient in analog hardware. Each carrier in an OFDM is a sinusoid with a frequency that is an integer multiple of a base or fundamental sinusoid frequency. Therefore, each carrier is a like a Fourier series component of the composite signal. In fact, it will be shown later that an OFDM signal is created in the frequency domain, and then transformed into the time domain via the Discrete Fourier Transform(DFT).

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저압 전력선 채널 특성을 고려한 OFDM변조 전송

  • Kang Duk-Ha;Heo Yoon-Seok;Cho Ki-Hyung;Lee Dae-Young
    • The Journal of Information Technology
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    • v.6 no.2
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    • pp.1-8
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    • 2003
  • This paper is about power line communication(PLC) over the low power voltage grid. The main advantage with power line communication is the use of an existing infrastructure. The PLC channel can be modeled as having multi-path propagation with frequency-selective fading, typical power lines exhibit signal attenuation increasing with length and frequency. OFDM(Orthogonal Frequency Division Multiplexing) is a modulation technique where multiple low data rate carriers are combined by a transmitter to form a composite high data rate transmission. To implement the multiple carrier scheme using a bank of parallel modulators would not be very efficient in analog hardware. Each carrier in an OFDM is a sinusoid with a frequency that is an integer multiple of a base or fundamental sinusoid frequency. Therefore, each carrier is a like a Fourier series component of the composite signal. In fact, it will be shown later that an OFDM signal is created in the frequency domain, and then transformed into the time domain via the Discrete Fourier Transform(DFT).

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Modified Modular Multilevel Converter with Submodule Voltage Fluctuation Suppression

  • Huang, Xin;Zhang, Kai;Kan, Jingbo;Xiong, Jian
    • Journal of Power Electronics
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    • v.17 no.4
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    • pp.942-952
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    • 2017
  • Modular multilevel converters (MMCs) have been receiving extensive research interest in high/medium-voltage applications due to its modularity, scalability, reliability, high-voltage capability, and excellent harmonic performance. Submodule capacitors are usually rather bulky because they have to withstand fundamental frequency voltage fluctuations. To reduce the capacitance of these capacitors, this study proposes a modified MMC with an active power decoupling circuit within each submodule. The modified submodule contains an auxiliary half bridge, with its capacitor split in two. Also, the midpoints of the half bridge and the split capacitors are connected by an inductor. With this modified submodule, the fundamental frequency voltage fluctuation can be suppressed to a great extent. The second-order voltage fluctuation, which is the second most significant component in submodule voltage fluctuations, is removed by the proper control of the second-order circulating current. Consequently, the submodule capacitance is significantly reduced. The viability and effectiveness of the proposed new MMC are confirmed by the simulation and experimental results. The proposed MMC is best suited for medium-voltage applications where power density is given a high priority.

New Zero-Voltage-Switching PWM Inverter (새로운 제로 전압 스위칭 PWM 인버터)

  • 곽동걸;이현우;서기영;권순걸;우정인
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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    • 1992.11a
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    • pp.47-50
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    • 1992
  • In this paper, the authors propose a so-called new zero voltage switching circuit topology arts an improved PWM strategy. In order to minimize voltage stress in dc-ac high switching frequency power conversion, the proposal circuit is used as interface between DC sully and the PWM inverter. The new ZVS circuit provide PWM inverter with a short zero voltage period in the dc 1ink just before inverter switches operate. By using the proposed modulating signal (transformational sinewave) art carrier sinal (sawtooth ware), the amplitude of the fundamental component is increased about 15 percent more than that of a conventional sinusoidal modulating signal and triangular carrier signal, the switching tosses is reduced. Some simulative results on computer are included to confirm the validity of the analytical results.

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Reduction of Periodic Speed Ripple of Electric Machines Using Resonant Controller and Repetitive Controller (공진제어기와 반복제어기를 사용한 전동기의 주기적인 속도 리플 저감)

  • Jung, Sung-Min;Lee, Jung-Ho;Choi, Jong-Woo
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.67 no.11
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    • pp.1434-1446
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    • 2018
  • This paper presents new speed control strategy for periodic load torque injected in AC motor. If motor drive system has a periodic load torque, it causes a periodic motor speed ripple bringing about vibrations and noises. This paper proposed new control method consisting of PIR(proportional-integral-resonant) controller and repetitive controller. PIR controller controls DC, low frequency and fundamental components and repetitive controller controls other harmonics. The performance has been verified through computer simulations using MATLAB Simulink and experiments.

Wavelet PWM Technique for Single-Phase Three-Level Inverters

  • Zheng, Chun-Fang;Zhang, Bo;Qiu, Dong-Yuan;Zhang, Xiao-Hui;Xiao, Le-Ming
    • Journal of Power Electronics
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    • v.15 no.6
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    • pp.1517-1523
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    • 2015
  • The wavelet PWM (WPWM) technique has been applied in two-level inverters successfully, but directly applying the WPWM technique to three-level inverters is impossible. This paper proposes a WPWM technique suitable for a single-phase three-level inverter. The work analyzes the control strategy with the WPWM and obtains the design of its parameters. Compared with the SPWM technique for a single-phase three-level inverter under the same conditions, the WPWM can obtain high magnitudes of the output fundamental frequency component, low total harmonic distortion, and simpler digital implementation. The feasibility experiment is given to verify of the proposed WPWM technique.

A Study on IGBT inverter for sinusoidal wave output PAM type (PAM-PWM 인버터에 의한 정현파출현)

  • 이현우;정기화;우정인
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.17 no.5
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    • pp.521-528
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    • 1992
  • this paper a new PAM-PWM Inverter using IGBT Is described. The output waveforms in the proposed PAM-PWM inverter are investigated both theoretiically and experimentally. The line-voltage waveform is composed of fundamental component and the sidebands of carrier frequency. The lower order harmonics are not included In the output waveform. As each inverter arm does not operate during two-thirds period, the heats, generated in the devices are reduced. That is the size of the inverter system can be minimized because of the reduction In the heat dissipating equipemnt.

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