• Title/Summary/Keyword: Pulse phase modulation

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Lifetime Evaluation of Power Devices of Single-Phase 5-Level NPC Inverters Considering Mission Profile of PV Systems (미션 프로파일을 고려한 단상 5-레벨 태양광 NPC 인버터의 전력 반도체 소자 수명 분석)

  • Ryu, Taerim;Choi, Ui-Min
    • The Transactions of the Korean Institute of Power Electronics
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    • v.27 no.3
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    • pp.221-227
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    • 2022
  • The reliability improvement of PV systems is an important factor in reducing the cost of PV energy because it is closely related to the annual energy production as well as the maintenance cost of PV systems. The reliability of PV inverters plays a key role in the reliability of PV systems because it is regarded as one of the most reliable critical parts of PV systems. The lifetime evaluation of PV inverters considering the mission profile in the design phase plays an important role in reliability design to ensure the required lifetime of PV inverters. In this paper, the lifetime of representative single-phase T-type and I-type NPC inverters are comparatively evaluated by considering the mission profile of a PV system recorded at Iza, Spain. Furthermore, the effect of the pulse width modulation methods on the lifetime is also discussed. The lifetime evaluation of PV inverters is performed at the component-level first and then the system level by considering all power devices.

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.

Exploitation of Spatial Diversity in a Novel Cooperative Spectrum Sharing Method based on PAM and Modified PAM Modulation

  • Tran, Truc Thanh;Kong, Hyung Yun
    • Journal of Communications and Networks
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    • v.16 no.3
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    • pp.280-292
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    • 2014
  • This article presents a novel cooperative spectrum sharing (CSS) scheme. The primary transmitter transmits a complex Quadrature amplitude modulation (QAM) signal in the first phase, and CSS occurs in the second phase. The secondary transmitter with the largest forwarding channel gain among the nodes that successfully decode the primary signal in the first phase is selected for CSS. This selected node employs a pulse-amplitude modulation (PAM) signal for primary information message (IM) instead of the QAM signal, and it employs a modified PAM signal for the secondary IM. The proposed modified PAM signal depends on the amplitude of the primary PAM signal. This method results in no mutual interference and negligible primary interference constraint and allows a higher degree of exploitation of spatial diversity, thus enabling increase in secondary power to improve primary transmission. The outage performance is enhanced in both the primary and secondary systems. The critical region, in which the primary outage performance is enhanced with the proposed CSS scheme, can be adjusted and widened by varying either the modulation cooperation sharing factor or the number of secondary transmitters.

An Improved Phase-Shifted Carrier PWM for Modular Multilevel Converters with Redundancy Sub-Modules

  • Choi, Jong-Yun;Han, Byung-Moon
    • Journal of Power Electronics
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    • v.16 no.2
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    • pp.473-479
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    • 2016
  • In this paper, the PSC PWM method is chosen as the optimal modulation method for a 20MW VSC HVDC, with consideration of the harmonic distortion of the output voltage, the switching frequency, and the control implementation difficulty. In addition, a new PSC PWM method is proposed in order to achieve an easy application and to solve the redundant control problems encountered in the previous PSC PWM method. To verify the proposed PSC PWM method, PSCAD/EMTDC simulations for an 11-level MMC RTDS HILS test and an 11-level MMC prototype converter test were performed. As can be seen from the results of these tests, the proposed PSC PWM method shows good results in an 11-level MMC with redundant sub-modules.

Adaptive Carrier-based PWM for a Four-Switch Three-Phase Inverter under DC-link Voltage Ripple Conditions

  • Nguyen, Tuyen D.;Lee, Hong-Hee;Nguyen, Hoang M.
    • Journal of Electrical Engineering and Technology
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    • v.5 no.2
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    • pp.290-298
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    • 2010
  • This paper proposes an adaptive carrier-based pulse width modulation (PWM) method for a four-switch three-phase (4S3P) inverter under dc-link voltage ripple conditions. The proposed method guarantees balanced output currents despite of the existence of the voltage oscillations across two dc-link capacitors. And also, this new approach achieves a linear over-modulation with calculation time reduction. Simulation and experimental results are given to validate the feasibility of the proposed method.

A New Three-Phase Current Modulation Method to Suppress the Commutation Torque Ripple of Brushless DC Motor

  • Wang, Zhiqiang;Yin, Shuai;Ma, Tiehua
    • Journal of Electrical Engineering and Technology
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    • v.12 no.5
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    • pp.1925-1933
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    • 2017
  • The brushless DC motor's commutation torque ripple is caused by inconsistency in the rate of phase current change. Thus, a method that considers armature resistance is proposed to modulate phase current. The three-phase control strategy, which involves the "open-phase conduction, off-phase pulse width modulation, and maintained non-commutation phase" technique, is applied during commutation at full-speed segments of the motor. Changes in each phase current are analyzed theoretically by establishing mathematical model based on phase current to determine the relative difference among shutdown phase, duty, and motor operating parameters. The turn-on and turn-off phase current change rates are made to be consistent to ensure less non-commutation phase current ripple, then the torque ripple is inhibited. The simulation results show that the phase commutation current and torque ripple coefficient of the proposed method are reduced from 56.9% and 55.5% to 6.8% and 6.1%, respectively. In the experiment system, the pulsation coefficient of the motor phase current is reduced from 40.0% to 16.7% at low speed and 50.0% to 18.8% at high speed. The simulation and experimental results show that the proposed control method significantly inhibits commutation current and torque in the full section.

Jamming Effect of Phase-Coded Pulse Compression Radar (위상코드 펄스압축 레이더의 재밍 효과)

  • Lim, Joong-Soo
    • Journal of Convergence for Information Technology
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    • v.9 no.5
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    • pp.125-129
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    • 2019
  • This paper describes the jamming effect of phase-coded pulse compression(PCPC) radar. Barker code radar, a typical PCPC radar, separates transmission pulses into 13 or 31 small pulses and phase modulates and transmits each pulse signal to increase radar detection efficiency and reduce the influence of jamming. Generally, when the radar is subjected to jamming, the detection distance becomes shorter and the detection error rate becomes higher. In the case of noise jamming or carrier jamming on the PCPC radar, the jamming effect is very small for no phase-coded convergence. However, the jamming effect is large in the case of synchronous jamming using the pulse-coded signal as a jamming signal with DRFM. It can be seen that the jamming effect increases when the storage time of the pulse-coded signal is prolonged. This study is considered to be useful for PCPC radar and EW jamming system design.

The Operation Characteristic of the LED Taxi Light for Wavelength According to Meteorological Changes for Hybrid System Using a ESS (하이브리드 시스템의 ESS를 이용한 기상변화의 파장별 LED 항공유도등 동작특성)

  • Hwang, Lark-Hoon;Kim, Jin-Sun;Na, Yong- Ju
    • Journal of Advanced Navigation Technology
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    • v.20 no.4
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    • pp.265-274
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    • 2016
  • In this study, the system was composed of the booster chopper and the power converter, which is a pulse width modulation (PWM) voltage inverter using a hybrid power generation system solar cell energy and wind force, Furthermore, in order to compensate the PWM voltage type inverter was linked with the general commercial power source, and through a normal operation of energy storage system (ESS), the system operated the LED Taxi Light by Wavelength according to Meteorological Changes at the airport in an efficient manner. The performance of the system was compared with the solar cell characteristics specification. In addition, for phase synchronization with the PWM voltage type inverter, the grid voltage was detected so as to operate the grid voltage and inverter output in the same phase and to connect the surplus electric power with the system. Finally, by developing a control circuit at the same time from which an excellent dynamic characteristics can be obtained through applying to the airport runway taxi light, it was concluded that a variety of taxi light can be pursued.

Pulse Width and Pulse Frequency Modulated Soft Commutation Inverter Type AC-DC Power Converter with Lowered Utility 200V AC Grid Side Harmonic Current Components

  • Matsushige T.;Ishitobi M.;Nakaoka M.;Bessyo D.;Yamashita H.;Omori H.;Terai H.
    • Proceedings of the KIPE Conference
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    • 2001.10a
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    • pp.484-488
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    • 2001
  • The grid voltage of commercial utility power source hi Japan and USA is 100rms, but in China and European countries, it is 200rms. In recent years, In Japan 200Vrms out putted single phase three wire system begins to be used for high power applications. In 100Vrms utility AC power applications and systems, an active voltage clamped quasi-resonant Inverter circuit topology using IGBTs has been effectively used so far for the consumer microwave oven. In this paper, presented is a half bridge type voltage-clamped high-frequency Inverter type AC-DC converter using which is designed for consumer magnetron drive used as the consumer microwave oven in 200V utility AC power system. This zero voltage soft switching Inverter can use the same power rated switching semiconductor devices and three-winding high frequency transformer as those of the active voltage clamped quasi-resonant Inverter using the IGBTs that has already been used for 100V utility AC power source. The operating performances of the voltage source single ended push pull type Inverter are evaluated and discussed for consumer microwave oven. The harmonic line current components In the utility AC power side of the AC-DC power converter operating at ZVS­PWM strategy reduced and improved on the basis of sine wave like pulse frequency modulation and sine wave like pulse width modulation for the utility AC voltage source.

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An Improved SVPWM Control of Voltage Imbalance in Capacitors of a Single-Phase Multilevel Inverter

  • Ramirez, Fernando Arturo;Arjona, Marco A.
    • Journal of Power Electronics
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    • v.15 no.5
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    • pp.1235-1243
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    • 2015
  • This paper presents a modified Space Vector Pulse Width Modulation Technique (SVPWM), which solves the well-known problem of voltage imbalance in the capacitors of a single-phase multilevel inverter. The proposed solution is based on the measurement of DC voltage levels at each capacitor of the inverter DC bus. The measurements are then used to adjust the size of the active vectors within the SVPWM algorithm to keep the voltage waveform sinusoidal regardless of any voltage imbalance on the DC link capacitors. When a voltage deviation exceeds a predetermined hysteresis band, the correspondent voltage vector is restricted to restore the voltage level to an acceptable threshold. Hence, the need for external voltage regulators for the voltage capacitors is eliminated. The functionality of the proposed algorithm is successfully demonstrated through simulations and experiments on a grid tied application.