• Title/Summary/Keyword: Common control point

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COMMON FIXED POINT RESULTS FOR NON-COMPATIBLE R-WEAKLY COMMUTING MAPPINGS IN PROBABILISTIC SEMIMETRIC SPACES USING CONTROL FUNCTIONS

  • Das, Krishnapada
    • Korean Journal of Mathematics
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    • v.27 no.3
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    • pp.629-643
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    • 2019
  • In common fixed point problems in metric spaces several versions of weak commutativity have been considered. Mappings which are not compatible have also been discussed in common fixed point problems. Here we consider common fixed point problems of non-compatible and R-weakly commuting mappings in probabilistic semimetric spaces with the help of a control function. This work is in line with research in probabilistic fixed point theory using control functions. Further we support our results by examples.

An Optimized Control Method Based on Dual Three-Level Inverters for Open-end Winding Induction Motor Drives

  • Wu, Di;Su, Liang-Cheng;Wu, Xiao-Jie;Zhao, Guo-Dong
    • Journal of Power Electronics
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    • v.14 no.2
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    • pp.315-323
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    • 2014
  • An optimized space vector pulse width modulation (SVPWM) method with common mode voltage elimination and neutral point potential balancing is proposed for an open-end winding induction motor. The motor is fed from both of the ends with two neutral point clamped (NPC) three-level inverters. In order to eliminate the common mode voltage of the motor ends and balance the neutral point potential of the DC link, only zero common mode voltage vectors are used and a balancing control factor is gained from calculation in the strategy. In order to improve the harmonic characteristics of the output voltages and currents, the balancing control factor is regulated properly and the theoretical analysis is provided. Simulation and experimental results show that by adopting the proposed method, the common mode voltage can be completely eliminated, the neutral point potential can be accurately balanced and the harmonic performance for the output voltages and currents can be effectively improved.

CONTROL FUNCTION BASED COUPLED AND COMMON COUPLED FIXED POINT THEOREMS IN PARTIAL METRIC SPACES

  • H. K. Nashine;G. S. Saluja;G. V. V. Jagannadha Rao;W. H. Lim
    • Nonlinear Functional Analysis and Applications
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    • v.29 no.2
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    • pp.559-580
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    • 2024
  • In this paper, we aim to prove coupled and common coupled fixed point theorems for contractive type conditions in the context of partial metric spaces by means of a control function, and to provide some corollaries of the established results. This paper presents a number of results that generalize and extend previous work in the field. In order to better illustrate the process, we provide examples.

ON A COMMON FIXED POINT THEOREM IN INTUITIONISTIC MENGER SPACE VIA C CLASS AND INVERSE C CLASS FUNCTIONS WITH CLR PROPERTY

  • Ghemam Hamed Laid;Iqbal M. Batiha;Leila Benaoua;Taki Eddine Oussaeif;Besma Laouadi;Iqbal H. Jebril
    • Nonlinear Functional Analysis and Applications
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    • v.29 no.3
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    • pp.899-912
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    • 2024
  • The objective of this paper is to ascertain the existence and uniqueness of common fixed point for four self mappings in intuitionistic Menger metric spaces under some conditions extending to (CLR) property and C-class functions. Some illustrative examples are furnished, which demonstrate the validity of the hypotheses. As an application to our main result, we derive a common fixed point theorem for four self-mappings in metric space. Our results generalize several works, including [4], [20].

Control Strategy Compensating for Unbalanced Grid Voltage Through Negative Sequence Current Injection in PMSG Wind Turbines

  • Kang, Jayoon;Park, Yonggyun;Suh, Yongsug;Jung, Byoungchang;Oh, Juhwan;Kim, Jeongjoong;Choi, Youngjoon
    • Proceedings of the KIPE Conference
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    • 2013.07a
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    • pp.244-245
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    • 2013
  • This paper proposes a control algorithm for permanent magnet synchronous generator with a back-to-back three-level neutral-point clamped voltage source converter in a medium-voltage offshore wind power system under unbalanced grid conditions. The proposed control algorithm particularly compensates for the unbalanced grid voltage at the point of common coupling in a collector bus of offshore wind power system. This control algorithm has been formulated based on the symmetrical components in positive and negative rotating synchronous reference frames under generalized unbalanced operating conditions. Instantaneous active and reactive power are described in terms of symmetrical components of measured grid input voltages and currents. Negative sequential component of ac input current is injected to the point of common coupling in the proposed control strategy. The amplitude of negative sequential component is calculated to minimize the negative sequential component of grid voltage under the limitation of current capability in a voltage source converter. The proposed control algorithm makes it possible to provide a balanced voltage at the point of common coupling resulting in the generated power of high quality from offshore wind power system under unbalanced network conditions.

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Carrier Based Common Mode Voltage Reduction Techniques in Neutral Point Clamped Inverter Based AC-DC-AC Drive System

  • Ojha, Amit;Chaturvedi, Pradyumn;Mittal, Arvind;Jain, Shailendra
    • Journal of Power Electronics
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    • v.16 no.1
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    • pp.142-152
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    • 2016
  • Common mode voltage (CMV) generation is a major problem in switching power converter fed induction motor drive systems. CMV is the zero sequence voltage generated due to the switching action of power converters. Even a small magnitude of CMV with a high rate of change may circulate large bearing currents which may damage a machine's bearings and shorten its life. There are several methods of controlling CMV. This paper presents 3-level sinusoidal pulse width modulation based techniques to control the magnitude and rate of change of CMV in multilevel AC-DC-AC drive systems. Simulation and experimental investigations have been presented to validate the performance of proposed technique to control CMV in 3-level neutral point clamped inverter based AC-DC-AC system.

Reactive Power Control Algorithm of Grid-Connected Inverter at the Point of Common Coupling With Compensation of Series and Parallel Impedances (직병렬 임피던스 보상을 통한 계통 연계 분산전원 인버터의 PCC 무효전력 제어 알고리즘)

  • Heo, Cheol-Young;Song, Seung-Ho;Kim, Yong-Rae
    • The Transactions of the Korean Institute of Power Electronics
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    • v.27 no.2
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    • pp.92-99
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    • 2022
  • Due to space and geographical constraints, the power source may be located outside the island area, resulting in the considerable length of transmission line. In these cases, when an active power is transmitted, unexpected reactive power is generated at a point of common coupling (PCC). Unlike the power transmitted from the power generation source, the reactive power adversely affects the system. This study proposes a new algorithm that controls reactive power at PCC. Causes of reactive power errors are separated into parallel and series components, which allows the algorithm to compensate the reactive current of the inverter output and control reactive power at the PCC through calculations from the impedance, voltage, and current. The proposed algorithm has economic advantages by controlling the reactive power with the inverter of the power source itself, and can flexibly control power against voltage and output variations. Through the simulation, the algorithm was verified by implementing a power source of 3 [kVA] capacity connected to the low voltage system and of 5 [MVA] capacity connected to the extra-high voltage system. Furthermore, a power source of 3 [kVA] capacity inverter is configured and connected to a mock grid, then confirmed through experiments.

A New Assessment for the Total Harmonic Contributions at the Point of Common Coupling

  • Han, Jong-Hoon;Lee, Kyebyung;Song, Chong Suk;Jang, Gilsoo;Byeon, Gilsung;Park, Chang-Hyun
    • Journal of Electrical Engineering and Technology
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    • v.9 no.1
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    • pp.6-14
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    • 2014
  • A new method to determine the total harmonic contributions of several customers and the utility at the point of common coupling is presented. The proposed method can quantify the individual harmonic impact of each suspicious harmonic source at the point of common coupling. The individual harmonic impact index is then used to assess the total harmonic contribution of each harmonic source. This index can be calculated by the results processed from instantaneous harmonic voltage and current phasor values. The results demonstrate the performance of the proposed method in terms of steady-state accuracy and response to time-varying operating conditions. The proposed index can be used for billing purposes to control harmonic distortion levels in power systems.

A Switching Method of Single Phase Grid Connected Inverter for Common Mode Noise Reduction (계통연계형 단상인버터의 Common Mode Noise 저감을 위한 Switching 방법)

  • Lee, Seung-Ju;Hong, Chang-Pyo;Kim, Hag-Wone;Cho, Kwan-Yuhl
    • The Transactions of the Korean Institute of Power Electronics
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    • v.21 no.1
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    • pp.27-33
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    • 2016
  • A pulse-width modulation (PWM) method for common mode noise reduction in a PWM inverter connected to a single-phase grid is proposed in this study. The extensively used conventional switching method may experience common mode voltage problems, which generate current leakage and electromagnetic induction problems. In the proposed switching method, the neutral point of the output voltage is always fixed at both ends of the input voltage to reduce common mode noise. The validity of the proposed method is proven through simulation and experimental results.

Carrier Based LFCPWM for Leakage Current Reduction and NP Current Control in 3-Phase 3-Level Converter (3상 3-레벨 컨버터의 누설전류 저감과 NP 전류 제어를 위한 캐리어 기반 LFCPWM)

  • Lee, Eun-Chul;Choi, Nam-Sup
    • The Transactions of the Korean Institute of Power Electronics
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    • v.27 no.5
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    • pp.446-454
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    • 2022
  • This study proposes a carrier-based pulse width modulation (PWM) method for leakage current reduction and neutral point (NP) current control in a three-phase three-level converter, which is a carrier-based PWM version of the previously proposed low-frequency common mode voltage PWM. Three groups of space vectors with the same common mode voltage are used. When the averaged NP current needs to be positive or negative, the specific groups are employed to produce low-frequency common mode voltages. The validity of the proposed PWM method is verified through experiments.