Applied sciences

Archives of Electrical Engineering

Content

Archives of Electrical Engineering | 2023 | vol. 72 | No 4

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Abstract

This study describes a method that allows the modelling of magnetisation processes in transformer steel sheets for any direction of the magnetic field strength. In the proposed approach, limiting hysteresis loops for the rolling and transverse directions were used. These loops are modified depending on the magnetisation angle between the direction of the field strength vector and rolling direction. For this purpose, unique correction coefficients, which are functions of the magnetisation angle, were applied for both hysteresis loops. An algorithm for determining the limiting hysteresis loops for any magnetisation angle is presented herein. The calculation results for several cases of magnetisation were compared with the measured hysteresis loops.
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Authors and Affiliations

Michał Sierżęga
1
ORCID: ORCID
Witold Mazgaj
1
ORCID: ORCID

  1. Department of Electrical Engineering, Cracow University of Technology, 24 Warszawska str., 31-155 Kraków, Poland
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Abstract

The paper presents a honey badger algorithm (HB) based on a modified backwardforward sweep power flow method to determine the optimal placement of droop-controlled dispatchable distributed generations (DDG) corresponding to their sizes in an autonomous microgrid (AMG). The objectives are to minimise active power loss while considering the reduction of reactive power loss and total bus voltage deviation, and the maximisation of the voltage stability index. The proposed HB algorithm has been tested on a modified IEEE 33-bus AMG under four scenarios of the load profile at 40%, 60%, 80%, and 100% of the rated load. The analysis of the results indicates that Scenario 4, where the HB algorithm is used to optimise droop gains, the positioning of DDGs, and their reference voltage magnitudes within a permissible range, is more effective in mitigating transmission line losses than the other scenarios. Specifically, the active and reactive power losses in Scenario 4 with the HB algorithm are only 0.184% and 0.271% of the total investigated load demands, respectively. Compared to the base scenario (rated load), Scenario 4 using the HB algorithm also reduces active and reactive power losses by 41.86% and 31.54%, respectively. Furthermore, the proposed HB algorithm outperforms the differential evolution algorithm when comparing power losses for scenarios at the total investigated load and the rated load. The results obtained demonstrate that the proposed algorithm is effective in reducing power losses for the problem of optimal placement and size of DDGs in the AMG.
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Authors and Affiliations

Tham X. Nguyen
1
ORCID: ORCID
Robert Lis
1
ORCID: ORCID

  1. Faculty of Electrical Engineering, Wrocław University of Science and Technology, Wybrzeze Wyspianskiego 27, 50-370 Wrocław, Poland
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Abstract

Induction motors (IMs) experience power losses when a portion of the input power is converted to heat instead of driving the load. The combined effect of copper losses, core losses, and mechanical losses results in IM power losses. Unfortunately, the core losses in the motor, which have a considerable impact on its energy efficiency, are not taken into account by the generally employed dynamic model in the majority of the studies. Due to this, the motor rating often corresponds to the worst-case load in applications, but the motor frequently operates below rated conditions. A hybridized model reference adaptive system (MRAS) with sliding mode control (SMC) is used in this study for sensorless speed control of an induction motor with core loss, allowing the motor to operate under a variety of load conditions. As a result, the machine can run at maximum efficiency while carrying its rated load. By adjusting the ��-axis current in the �� - �� reference frame in vector-controlled drives, the system’s performance is enhanced by running the motor at its optimum flux. Regarding the torque and speed of both induction motors with and without core loss, the Adaptive Observer Sliding Mode Control (AOSMC) has been constructed and simulated in this case. The AOSMC with core loss produced good performance when the proposed controller was tested.
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Authors and Affiliations

Tadele Ayana
1
ORCID: ORCID
Lelisa Wogi
1
ORCID: ORCID
Marcin Morawiec
1
ORCID: ORCID

  1. Faculty of Electrical and Control Engineering, Gdansk University of Technology, Gabriela Narutowicza 11/12, 80-233 Gdansk, Poland
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Abstract

This paper proposes an augmented speed control scheme of dual induction motors fed by a five-leg voltage source inverter (VSI) with a common/shared-leg. An additional control loop is proposed here and based on the mutual flux angle – the difference between flux angular positions of the IMs. The main purpose of this research is to minimize the energy losses in the common inverter leg by controlling the mutual flux angle, at equal angular speeds of both motors. Simulation and experimental studies were carried out and the effectiveness of the proposed control method was proven. The PLECS software package was used for the simulation tests. The laboratory prototypewas prepared for the experimental validation. All results were provided and discussed in this paper.
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Authors and Affiliations

Dmytro Kondratenko
1
ORCID: ORCID
Arkadiusz Lewicki
1
ORCID: ORCID
Krzysztof Łuksza
1
ORCID: ORCID

  1. Faculty of Electrical and Control Engineering, Gdansk University of Technology, 11/12 Narutowicza str., 80-233 Gdansk, Poland
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Abstract

The abundant use of solar energy in Indonesia has the potential to become electrical energy in a microgrid system. Currently the use of renewable energy sources (RESs) in Indonesia is increasing in line with the reduction of fossil fuels. This paper proposes a new microgrid DC configuration and designs a centralized control strategy to manage the power flow from renewable energy sources and the load side. The proposed design uses three PV arrays (300 Wp PV module) with a multi-battery storage system (MBSS), storage (200 Ah battery). Centralized control in the study used an outseal programmable logic controller (PLC). In this study, the load on the microgrid is twenty housing, so that the use of electrical energy for one day is 146.360 Wh. It is estimated that in one month it takes 4.390.800 Wh of electrical energy. The new DC microgrid configuration uses a hybrid configuration, namely the DC coupling and AC coupling configurations.The results of the study show that the DC microgrid hybrid configuration with centralized control is able to alternately regulate the energy flow from the PV array and MBSS. The proposed system has an efficiency of 98% higher than the previous DC microgrid control strategy and configuration models.
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Authors and Affiliations

Adhi Kusmantoro
1
Irna Farikhah
2

  1. Department of Electrical Engineering, Universitas PGRI Semarang Jl. Sidodadi Timur No. 24 – Dr. Cipto, Semarang 50125, Indonesia
  2. Department of Mechanical Engineering, Universitas PGRI Semarang, Jl. Sidodadi Timur No. 24 – Dr. Cipto, Semarang 50125, Indonesia
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Abstract

Dynamic characteristics for three types of railgun constructions were simulated and measured in this work. The simplest construction is the iron-less (IL) railgun, while the two other ones (IC and ICPM) have an iron-core. The iron-core permanent magnet (ICPM) railgun additionally has permanent magnets. To compare their characteristics, similar dimensions of the rails and iron cores were adopted, and the same power supply system was used. Numerical magnetic field analyses and our analytical models have been used to determine the electromagnetic parameters. They were verified experimentally. The transient states of the railguns were studied with our field-circuit mathematical model, and their results were also verified by experiments.
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Authors and Affiliations

Paweł Piekielny
1
ORCID: ORCID
Bronisław Tomczuk
1
ORCID: ORCID
Andrzej Waindok
1
ORCID: ORCID

  1. Department of Electrical Engineering and Mechatronics, Opole University of Technology, Prószkowska 76 str., 45-758 Opole, Poland
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Abstract

In response to the inability of the flexible DC transmission system connected to the AC grid under conventional control strategies to provide inertia to the system as well as to participate in frequency regulation, a virtual synchronous generator (VSG) control strategy is proposed for a voltage source converter (VSC)-based multi-terminal high-voltage direct current (VSC-MTDC) interconnection system. First, the virtual controller module is designed by coupling AC frequency and active power through virtual inertia control, so that the VSC-MTDC system can provide inertia response for AC grid frequency. Second, by introducing the power margin of the converter station into the droop coefficient, the unbalanced power on the DC side is reasonably allocated to reduce the overshoot of the DC voltage in the regulation process. Finally, the power regulation capability of the normal AC system is used to provide power support to the fault end system, reducing frequency deviations and enabling inter-regional resource complementation. The simulation model of the three-terminal flexible DC grid is built in PSCAD/EMTDC, and the effectiveness of the proposed control strategy is verified by comparing the conventional control strategy and the additional frequency control strategy.
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Authors and Affiliations

Congshan Li
1
ORCID: ORCID
Xiaowei Zhang
1
Ping He
1
ORCID: ORCID
Zikai Zhen
1
ORCID: ORCID
Kefeng Zhao
1

  1. College of Electrical Information Engineering, Zhengzhou University of Light Industry, China
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Abstract

Due to the nonlinear current-voltage (I-V) relationship of the photovoltaic (PV) module, building a precise mathematical model of the PV module is necessary for evaluating and optimizing the PV systems. This paper proposes a method of building PV parameter estimation models based on golden jackal optimization (GJO). GJO is a recently developed algorithm inspired by the idea of the hunting behavior of golden jackals. The explored and exploited searching strategies of GJO are built based on searching for prey as well as harassing and grabbing prey of golden jackals. The performance of GJO is considered on the commercial KC200GT module under various levels of irradiance and temperature. Its performance is compared to well-known particle swarm optimization (PSO), recent Henry gas solubility optimization (HGSO) and some previous methods. The obtained results show that GJO can estimate unknown PV parameters with high precision. Furthermore, GJO can also provide better efficiency than PSO and HGSO in terms of statistical results over several runs. Thus, GJO can be a reliable algorithm for the PV parameter estimation problem under different environmental conditions.
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