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3 pages, 164 KiB

Open AccessEditorial

Special Issue on “Modeling, Analysis and Control Processes of New Energy Power Systems”

by Haoming Liu, Jingrui Zhang and Jian Wang

Processes 2023, 11(1), 235; https://doi.org/10.3390/pr11010235 - 11 Jan 2023

Cited by 1 | Viewed by 1426

Abstract

In recent years, global climate change, environmental pollution, and energy shortage have become increasingly serious [...] Full article

(This article belongs to the Special Issue Modeling, Analysis and Control Processes of New Energy Power Systems)

Research

Jump to: Editorial

20 pages, 4559 KiB

Open AccessArticle

Predictive Commutation Failure Suppression Strategy for High Voltage Direct Current System Considering Harmonic Components of Commutation Voltage

by Xiaolin Liu, Zeyu Cao, Bingtuan Gao, Zhuan Zhou, Xingang Wang and Feng Zhang

Processes 2022, 10(10), 2073; https://doi.org/10.3390/pr10102073 - 13 Oct 2022

Cited by 5 | Viewed by 1991

Abstract

The commutation failure of high voltage direct current (HVDC) systems could lead to unstable operation of the alternating current/direct current (AC/DC) hybrid power grid. The commutation voltage distortion caused by harmonics is a considerable but unclear factor of commutation failure. According to the [...] Read more.

The commutation failure of high voltage direct current (HVDC) systems could lead to unstable operation of the alternating current/direct current (AC/DC) hybrid power grid. The commutation voltage distortion caused by harmonics is a considerable but unclear factor of commutation failure. According to the control switching process of HVDC systems, the commutation voltage-time area method is employed to analyze and reveal the influence mechanism of harmonic components of commutation voltage on first and subsequent commutation failures. Considering the distortion characteristics of AC voltage, a predictive commutation failure suppression strategy considering multiple harmonics of commutation voltage is proposed. In this strategy, the new extinction angle and the zero-crossing offset angle after voltage distortion are calculated considering the harmonic components so as to obtain the compensation margin of the lag trigger angle by combining the correction margin with the voltage change rate. Moreover, the tuning method of parameters of extinction angle and voltage prediction variables are provided. Finally, a case study based on CIGRE standard HVDC system is performed and analyzed by using power systems computer-aided design (PSCAD) software. Compared with the International Council on Large Electric systems (CIGRE) standard test model and traditional commutation failure prevention (CFPREV) control model, the results verify that the proposed strategy can effectively reduce the risk of first and subsequent commutation failures and improve the sensitivity of CFPREV control. Full article

(This article belongs to the Special Issue Modeling, Analysis and Control Processes of New Energy Power Systems)

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17 pages, 4922 KiB

Open AccessArticle

Time-of-Use Pricing Strategy of Integrated Energy System Based on Game Theory

by Xiaoling Yuan, Yi Guo, Can Cui and Hao Cao

Processes 2022, 10(10), 2033; https://doi.org/10.3390/pr10102033 - 8 Oct 2022

Cited by 2 | Viewed by 1870

Abstract

The integrated energy system is the mainstream energy utilization form of integrating a power system, natural gas system and thermal system, which provides a new way to solve the problem of renewable energy accommodation. The integrated energy system includes a variety of energy [...] Read more.

The integrated energy system is the mainstream energy utilization form of integrating a power system, natural gas system and thermal system, which provides a new way to solve the problem of renewable energy accommodation. The integrated energy system includes a variety of energy generation and conversion equipment, and its internal electricity, gas, cooling and thermal systems must balance the multiple energy supplies required by users. The integrated energy supplier (IES) and integrated energy user (IEU), as different stakeholders, pursue the maximization of their own profit. However, integrated energy suppliers should consider their market share and the sustainability of participating in market competition. Based on the constraints of energy access, conversion and accommodation, and the equipment for energy generation, conversion and consumption, we established an energy flow model. Constrained by the dynamic equilibrium of the supply of integrated energy suppliers and the demand of integrated energy users, a Stackelberg game model of integrated energy suppliers and users was established, and the existence of a Nash equilibrium solution of the game was proved. A genetic algorithm was used to solve the Nash equilibrium solution under two conditions aiming at the integrated energy supplier’s maximum profit and target profit. Considering the demand of integrated energy users in different time periods, we analyzed the time-of-use pricing strategy of the integrated energy based on the balance of the energy supply and demand. The results of a case study show that if integrated energy suppliers adopt the time-of-use pricing strategy of maximum profit, the energy load distribution of integrated energy users can be smoothed, and energy utilization and economic benefits of the system can be improved. If integrated energy suppliers adopt the time-of-use pricing strategy of target profit, enlarge the market by limiting their own profit and obtain the purchase willingness of integrated energy users by reducing the energy price, they can have a larger market share, a more reliable profit and a guarantee of long-term participation in market transactions. Full article

(This article belongs to the Special Issue Modeling, Analysis and Control Processes of New Energy Power Systems)

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16 pages, 3655 KiB

Open AccessArticle

Fault Diagnosis of Wind Turbine Main Bearing in the Condition of Noise Based on Generative Adversarial Network

by Zhixin Fu, Zihao Zhou and Yue Yuan

Processes 2022, 10(10), 2006; https://doi.org/10.3390/pr10102006 - 4 Oct 2022

Cited by 5 | Viewed by 1746

Abstract

In order to solve the problem that the fault classification accuracy of the main bearing of the wind turbine is not high due to the unbalanced vibration signal data of the main bearing of the wind turbine under the background of noise, this [...] Read more.

In order to solve the problem that the fault classification accuracy of the main bearing of the wind turbine is not high due to the unbalanced vibration signal data of the main bearing of the wind turbine under the background of noise, this article proposes a double-layer fault diagnosis model for the main bearing of the wind turbine that combines the auxiliary classifier generation adversarial network (ACGAN) and the deep residual shrinkage network (DRSN). First, the wind turbine main bearing data is sent into the ACGAN to learn the distribution features of fault data, and a particular type of fault data is generated to expand the original dataset to achieve balance conditions, and then the expanded dataset is sent to the DRSN to reduce noise to improve the fault classification accuracy. The simulation results show that, compared with the traditional deep learning model, the model proposed in this article can significantly improve the classification accuracy of the main bearing fault of wind turbines under noise conditions, and also has a strong diagnosis ability in a state of datasets with different loads. Full article

(This article belongs to the Special Issue Modeling, Analysis and Control Processes of New Energy Power Systems)

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14 pages, 4612 KiB

Open AccessArticle

Static Voltage Stability Assessment Using a Random UnderSampling Bagging BP Method

by Zhujun Zhu, Pei Zhang, Zhao Liu and Jian Wang

Processes 2022, 10(10), 1938; https://doi.org/10.3390/pr10101938 - 26 Sep 2022

Cited by 5 | Viewed by 1506

Abstract

The increase in demand and generator reaching reactive power limits may operate the power system in stressed conditions leading to voltage instability. Thus, the voltage stability assessment is essential for estimating the loadability margin of the power system. The grid operators urgently need [...] Read more.

The increase in demand and generator reaching reactive power limits may operate the power system in stressed conditions leading to voltage instability. Thus, the voltage stability assessment is essential for estimating the loadability margin of the power system. The grid operators urgently need a voltage stability assessment (VSA) method with high accuracy, fast response speed, and good scalability. The static VSA problem is defined as a regression problem. Moreover, an artificial neural network is constructed for online assessment of the regression problem. Firstly, the training sample set is obtained through scene simulation, power flow calculation, and local voltage stability index calculation; then, the class imbalance problem of the training samples is solved by the random under-sampling bagging (RUSBagging) method. Then, the mapping relationship between each feature and voltage stability is obtained by an artificial neural network. Finally, taking the modified IEEE39 node system as an example, by setting up four groups of methods for comparison, it is verified that the proposed method has a relatively ideal modeling speed and high accuracy, and can meet the requirements of power system voltage stability assessment. Full article

(This article belongs to the Special Issue Modeling, Analysis and Control Processes of New Energy Power Systems)

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19 pages, 7262 KiB

Open AccessArticle

Virtual Voltage Vector-Based Model Predictive Current Control for Five-Phase Induction Motor

by Qingfei Zhang, Jinghong Zhao, Sinian Yan, Yiyong Xiong, Yuanzheng Ma and Hansi Chen

Processes 2022, 10(10), 1925; https://doi.org/10.3390/pr10101925 - 23 Sep 2022

Cited by 3 | Viewed by 1830

Abstract

The high-performance control technology of multi-phase motors is a key technology for the application of multi-phase motors in many fields, such as electric transportation. The model predictive current control (MPCC) strategy has been extended to multi-phase systems due to its high dynamic performance. [...] Read more.

The high-performance control technology of multi-phase motors is a key technology for the application of multi-phase motors in many fields, such as electric transportation. The model predictive current control (MPCC) strategy has been extended to multi-phase systems due to its high dynamic performance. Model-predictive current control faces the problem that it cannot effectively regulate harmonic plane currents, and thus cannot obtain high-quality current waveforms because only one switching state is applied in a sampling period. To solve this problem, this paper uses the virtual vector-based MPCC to select the optimal virtual vector and apply it under the premise that the average value of the harmonic plane voltage in a single switching cycle is zero. Taking a five-phase induction motor as an example, the steady-state and dynamic performance of the proposed virtual vector MPCC and the traditional model predictive current control were simulated, respectively. Simulation results demonstrated the effectiveness of the proposed method in improving waveform quality while maintaining excellent dynamic performance. Full article

(This article belongs to the Special Issue Modeling, Analysis and Control Processes of New Energy Power Systems)

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19 pages, 1851 KiB

Open AccessArticle

Research on Low-Carbon Capability Evaluation Model of City Regional Integrated Energy System under Energy Market Environment

by Zhangbin Yang and Xiaojing Wang

Processes 2022, 10(10), 1906; https://doi.org/10.3390/pr10101906 - 20 Sep 2022

Cited by 4 | Viewed by 1599

Abstract

In the context of the “carbon peaking and carbon neutrality” goal and energy marketization, the City Regional Integrated Energy System (CRIES), as an important participant in the energy market, pursues low-carbon development as its most important goal. Without a reasonable market participation structure [...] Read more.

In the context of the “carbon peaking and carbon neutrality” goal and energy marketization, the City Regional Integrated Energy System (CRIES), as an important participant in the energy market, pursues low-carbon development as its most important goal. Without a reasonable market participation structure and a comprehensive low-carbon evaluation system, it will be difficult to meet the needs of CRIES for low-carbon development in the energy market. Therefore, this paper first proposes a framework suitable for CRIES to participate in the energy market, and under the influence of the operating characteristics of the energy market, proposes an evaluation index system suitable for CRIES’ low-carbon capabilities in the energy market. The analytic network process–criteria importance through intercriteria correlation (ANP-CRITIC) method is used to determine the subjective and objective weights of each indicator, and the comprehensive weight of each indicator is calculated by the principle of moment estimation to achieve a quantitative evaluation of the low-carbon capability of CRIES in the energy market. Finally, taking a CRIES as an example, the analysis verifies that the proposed evaluation model and method can scientifically and comprehensively evaluate the low-carbon capability of CRIES in the energy market. The results show that the CRIES low-carbon capability evaluation results of different market schemes can be improved by up to 24.9%, and a fairer market transaction mechanism can promote the low-carbon development of CRIES. Full article

(This article belongs to the Special Issue Modeling, Analysis and Control Processes of New Energy Power Systems)

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16 pages, 2344 KiB

Open AccessArticle

Cost Analysis of Synchronous Condenser Transformed from Thermal Unit Based on LCC Theory

by Chenghao Li, Mingyang Liu, Yi Guo, Hanqing Ma, Hua Wang and Xiaoling Yuan

Processes 2022, 10(9), 1887; https://doi.org/10.3390/pr10091887 - 17 Sep 2022

Cited by 6 | Viewed by 2941

Abstract

With the development of large-scale renewable energy consumption and multi-infeed high voltage direct current (HVDC) systems, the demand of a system for the synchronous condensers with a strong dynamic reactive power support capacity and a strong short-time overload capacity is increasing. Meanwhile, with [...] Read more.

With the development of large-scale renewable energy consumption and multi-infeed high voltage direct current (HVDC) systems, the demand of a system for the synchronous condensers with a strong dynamic reactive power support capacity and a strong short-time overload capacity is increasing. Meanwhile, with the reuse of a large number of retired thermal units, the most practical and economic way is to transform thermal units into synchronous condensers. The cost difference in the life-cycle of the synchronous condenser transformed from a thermal unit (SCTTU) and the newly established synchronous condenser (NESC) is a key factor that affects the decision-making and construction of the transformation from thermal unit to synchronous condenser. However, the life-cycle cost (LCC) of the synchronous condenser transformed from a thermal unit and the newly established synchronous condenser contains many uncertain factors, which affect the accuracy of the LCC estimation value. In order to quantify the impact of the blind information on the cost of the synchronous condenser station, blind number theory is introduced to establish the blind number model of the LCC of the synchronous condenser transformed from a thermal unit and the newly established synchronous condenser. Additionally, the LCC of the NESC and SCTTU with a different life-cycle under the capacity of 2 × 300 MVar are estimated. The results show that the cost of the SCTTU with a long service life of more than 15 years is significantly lower than that of the NESC and, thus, the SCTTU has better economic performance. The economic performance of the SCTTU with a life-cycle of less than 15 years is not better than that of the NESC. Compared with the traditional calculation method of a single cost value, the blind number model can obtain the possible distribution interval of LCC and the reliability of the corresponding interval, which makes the estimation results more valuable for practical engineering reference. Full article

(This article belongs to the Special Issue Modeling, Analysis and Control Processes of New Energy Power Systems)

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17 pages, 3480 KiB

Open AccessArticle

Optimization Strategy of Hybrid Configuration for Volatility Energy Storage System in ADN

by Guoping Lei, Yinhua Huang, Nina Dai, Li Cai, Li Deng, Shenghao Li and Chao He

Processes 2022, 10(9), 1844; https://doi.org/10.3390/pr10091844 - 13 Sep 2022

Cited by 4 | Viewed by 1498

Abstract

This study aims to address the issues of volatile energy access to the active distribution network (ADN), which are the difficulty of frequency regulation, the increased voltage deviation of the ADN, the decrease in operational security and stability, etc. In this study, a [...] Read more.

This study aims to address the issues of volatile energy access to the active distribution network (ADN), which are the difficulty of frequency regulation, the increased voltage deviation of the ADN, the decrease in operational security and stability, etc. In this study, a two-stage majorization configuration model is established to identify and understand how volatility energy affects a hybrid energy storage system (HESS). The ADN and HESS with lead-acid batteries and supercapacitors (SC) are examined using day forecast data for wind, solar, and load. In this planning stage, the integrated cost, network loss, and node voltage deviation are considered as optimal objectives in a multi-objective optimization model, while the revised multi-objective optimization particle swarm approach is used to solve the initial value of capacity configuration. In the operation stage, optimizing objectives like wind output power fluctuations, the frequency deviation of HESS is used to solve the modified value of the configuration capabilities of the SC, and the output of different types of units in ADN is further optimized by the quantum particle swarm with the addition of a chaotic mechanism. The simulation study is conducted to determine the best configuration result based on case 33 node examples, and the simulation results demonstrate the model’s viability. Full article

(This article belongs to the Special Issue Modeling, Analysis and Control Processes of New Energy Power Systems)

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22 pages, 8036 KiB

Open AccessArticle

Community Integrated Energy System Multi-Energy Transaction Decision Considering User Interaction

by Yuantian Li and Xiaojing Wang

Processes 2022, 10(9), 1794; https://doi.org/10.3390/pr10091794 - 6 Sep 2022

Cited by 6 | Viewed by 1503

Abstract

With the gradual liberalization of China’s energy market, the distributed characteristics of each entity in the community integrated energy system are more and more obvious, and the traditional centralized optimization is difficult to reveal the interaction between the entities. This paper aims to [...] Read more.

With the gradual liberalization of China’s energy market, the distributed characteristics of each entity in the community integrated energy system are more and more obvious, and the traditional centralized optimization is difficult to reveal the interaction between the entities. This paper aims to improve the profit of the community operator and the users’ value-added benefit of energy use, and proposes a multi-energy transaction decision of a community integrated energy system considering user interaction. First, a refined model of user interaction, including energy conversion, is established, and then the optimization model of multi-energy transaction decision between the community operator and the users is constructed based on the master–slave game. The upper layer aims to maximize the profit of the community operator according to the energy use strategies’ feedback from the users, decides the retail energy prices of the community operator to the users, and optimization variables include equipment output and energy purchased from the power grid and natural gas grid. The lower layer aims to maximize the value-added benefit of energy use for users. The users optimize their energy use strategies based on the retail energy prices published by the community operator. The model is solved by the differential evolution algorithm combined with the CPLEX solver. Finally, different scenarios are analyzed in a numerical example, and the results show that the strategy proposed in this paper to set community prices increases the community operator’s profit and profit margin by 5.9% and 7.5%, respectively, compared to using market energy prices directly. At the same time, the value-added benefit to users also increases by 15.2%. The community operator and users can achieve a win–win situation. Full article

(This article belongs to the Special Issue Modeling, Analysis and Control Processes of New Energy Power Systems)

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18 pages, 3296 KiB

Open AccessArticle

Layout Method of Met Mast Based on Macro Zoning and Micro Quantitative Siting in a Wind Farm

by Wenjin Chen, Gang Qian, Weiwen Qi, Gang Luo, Lin Zhao and Xiaoling Yuan

Processes 2022, 10(9), 1708; https://doi.org/10.3390/pr10091708 - 27 Aug 2022

Cited by 2 | Viewed by 2102

Abstract

In order to promote the wind monitoring accuracy and provide a quantitative planning method for met mast layout in practical projects, this paper proposes a two-stage layout method for met mast based on discrete particle swarm optimization (DPSO) zoning and micro quantitative siting. [...] Read more.

In order to promote the wind monitoring accuracy and provide a quantitative planning method for met mast layout in practical projects, this paper proposes a two-stage layout method for met mast based on discrete particle swarm optimization (DPSO) zoning and micro quantitative siting. Firstly, according to the wind turbines layout, rotational empirical orthogonal function and hierarchical clustering methods are used to preliminarily determine zoning number. Considering the geographical proximity of wind turbines and the correlation of wind speed, an optimal macro zoning model of wind farm based on improved DPSO is established. Then, combined with the grid screening method and optimal layout evaluation index, a micro quantitative siting method of met mast is proposed. Finally, the rationality and efficiency of macro zoning method based on improved DPSO, as well as the objectivity and standardization of micro quantitative siting, are verified by an actual wind farm. Full article

(This article belongs to the Special Issue Modeling, Analysis and Control Processes of New Energy Power Systems)

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17 pages, 4945 KiB

Open AccessArticle

Modeling and Analysis of New Power Devices Based on Linear Phase-Shifting Transformer

by Jie Xue, Jinghong Zhao, Sinian Yan, Hanming Wang, Changduo Zhou, Dongao Yan and Hansi Chen

Processes 2022, 10(8), 1596; https://doi.org/10.3390/pr10081596 - 12 Aug 2022

Cited by 2 | Viewed by 1547

Abstract

With the rapid development of new power systems, various new power devices have also been developed. It is very important to establish analytical models of new power devices to ensure or even improve the reliability and stability of the power system. A linear [...] Read more.

With the rapid development of new power systems, various new power devices have also been developed. It is very important to establish analytical models of new power devices to ensure or even improve the reliability and stability of the power system. A linear phase-shifting transformer (LPST) is a new type of power device that mainly relies on air gaps to transfer energy, so establishing an accurate air-gap magnetic field model is very important for improving the efficiency of this system. In this paper, an analytical model of an unequal-pitch linear phase-shifting transformer (UP-LPST) was established by combining the distributed magnetic circuit method (DMCM) and Schwartz–Christopher transformation (SCT). Taking the magnetic field strength as a variable, an accurate magnetic field analysis model for a UP-LPST considering saturation, cogging, and edge was established. Taking a 1 kw UP-LPST as a prototype, the accuracy of the model was verified by the finite element method and experiments. This modeling method could also be used to establish magnetic field models of other similar structures in new energy power systems, especially those with cogging structures. Full article

(This article belongs to the Special Issue Modeling, Analysis and Control Processes of New Energy Power Systems)

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14 pages, 3805 KiB

Open AccessArticle

An Improved Model for Five-Phase Induction Motor Based on Magnetic Noise Reduction Part I: Slot Opening Width

by Hansi Chen, Jinghong Zhao, Yiyong Xiong, Xiangyu Luo and Qingfei Zhang

Processes 2022, 10(8), 1496; https://doi.org/10.3390/pr10081496 - 29 Jul 2022

Cited by 3 | Viewed by 1353

Abstract

Based on the winding function considering the slot width and the air-gap permeability considering the slot opening width, the main radial electromagnetic force wave expressions of the induction motor are determined. The electromagnetic force-vibration prediction model of the induction motor is established. The [...] Read more.

Based on the winding function considering the slot width and the air-gap permeability considering the slot opening width, the main radial electromagnetic force wave expressions of the induction motor are determined. The electromagnetic force-vibration prediction model of the induction motor is established. The natural frequency and acoustic radiation model of a finite-length cylindrical shell with two ends clamped is deduced. On this basis, an improved magnetic noise prediction model of cage induction motor is improved, which can calculate the combined effects of electromagnetic force on the axis and circumferential modes of the stator system. Aiming at two different noise reduction targets, an optimization method is proposed to reduce the overall electromagnetic noise of the motor without sacrificing efficiency and output torque. The feasibility of the model for electromagnetic noise prediction is verified by finite element simulation and experiments. For a 30/26 slots five-phase induction motor, low-noise analysis and optimization schemes of the opening width for two different targets are given. The results show that the larger slot opening scheme can also result in less magnetic noise for the right selection, which is contrary to the common design rule that recommends minimizing slot opening to reduce magnetic noise. Full article

(This article belongs to the Special Issue Modeling, Analysis and Control Processes of New Energy Power Systems)

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15 pages, 34333 KiB

Open AccessArticle

Parameter Identification of Five-Phase Squirrel Cage Induction Motor Based on Extended Kalman Filter

by Xiangyu Luo, Jinghong Zhao, Yiyong Xiong, Hao Xu, Hansi Chen and Shuheng Zhang

Processes 2022, 10(8), 1440; https://doi.org/10.3390/pr10081440 - 23 Jul 2022

Cited by 6 | Viewed by 1645

Abstract

The use of multiphase electric drives in industrial applications has increased in the last few years. These machines’ advantages over the three-phase system make them appropriate for harsh working situations. To increase their inherent reliability, some authors have been working in sensorless control [...] Read more.

The use of multiphase electric drives in industrial applications has increased in the last few years. These machines’ advantages over the three-phase system make them appropriate for harsh working situations. To increase their inherent reliability, some authors have been working in sensorless control schemes, where the absence of an encoder ensures proper system performance. Nevertheless, these sensorless control systems present some problems due to the uncertainties of the parameters. In this regard, using extended Kalman filters overcomes this situation, since Kalman filters consider the system error and measurement error in the estimation process. However, when the three-phase Kalman filters are extended to the five-phase case of study, the complexity of the problem increases substantially. In this work, the authors propose an extended Kalman filter, which discomposes the original state equation, reducing the complexity of the estimation stage. In addition, the system suppresses the third-harmonic injection, which enhances the overall phase-current quality. Full article

(This article belongs to the Special Issue Modeling, Analysis and Control Processes of New Energy Power Systems)

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16 pages, 7829 KiB

Open AccessArticle

An Improved Model for Five-Phase Induction Motor Based on Magnetic Noise Reduction Part II: Pole-Slot Scheme

by Hansi Chen, Jinghong Zhao, Yiyong Xiong, Sinian Yan and Hao Xu

Processes 2022, 10(8), 1430; https://doi.org/10.3390/pr10081430 - 22 Jul 2022

Cited by 1 | Viewed by 1762

Abstract

For the reduction in the electromagnetic noise level of three-phase induction motors, many empirical rules and analytical models have been established to select the matching scheme of pole and slot, but they are not fully applicable to five-phase squirrel cage induction motors (FSCIM). [...] Read more.

For the reduction in the electromagnetic noise level of three-phase induction motors, many empirical rules and analytical models have been established to select the matching scheme of pole and slot, but they are not fully applicable to five-phase squirrel cage induction motors (FSCIM). In this paper, combined with the slot-number phase diagram (SNPD), and the electromagnetic force-vibration-acoustic analytical model deduced in Part I, the influence of pole-slot schemes, including five-phase regular-size phase-belt and fractional-slot winding, on magnetic noise is analyzed. The feasibility of electromagnetic noise prediction is verified by finite element simulation and experiments. Taking a 4 kW FSCIM as a prototype, noise prediction is carried out for all the slot-number matching schemes with pole pairs not exceeding three. For two noise reduction targets, which reduce the maximum single-frequency noise in the steady-state operation and the average noise during startup, the pole-slot numbers matching rule of FSCIM is given. This improved model is also applicable in different power ranges for the noise reduction design of five-phase motors. Full article

(This article belongs to the Special Issue Modeling, Analysis and Control Processes of New Energy Power Systems)

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17 pages, 3509 KiB

Open AccessArticle

Multi-Objective Optimal Scheduling for Multi-Renewable Energy Power System Considering Flexibility Constraints

by Lei Yang, Wei Huang, Cheng Guo, Dan Zhang, Chuan Xiang, Longjie Yang and Qianggang Wang

Processes 2022, 10(7), 1401; https://doi.org/10.3390/pr10071401 - 18 Jul 2022

Cited by 5 | Viewed by 1632

Abstract

As renewable energy penetration increases, the lack of flexibility in a multi-renewable power system can seriously affect its own economics and reliability. To address this issue, three objectives are considered in this study: power fluctuations on tie-line, operating cost, and curtailment rate of [...] Read more.

As renewable energy penetration increases, the lack of flexibility in a multi-renewable power system can seriously affect its own economics and reliability. To address this issue, three objectives are considered in this study: power fluctuations on tie-line, operating cost, and curtailment rate of renewable energy. Presented also is an optimal day-ahead scheduling model based on the MREPS for distributed generations with flexibility constraints. The multi-objective particle swarm optimization (MOPSO) algorithm can be applied to obtain a set of Pareto non-dominated solutions for the day-ahead scheduling strategy with the proposed model. By using fuzzy comprehensive evaluation, the optimal compromise solution is determined in the set. The presented method sacrifices a small amount of economy and power fluctuation, but it can reduce the deviation between forecast and realized power fluctuations on the tie-line, while improving the utilization of renewable energy. Full article

(This article belongs to the Special Issue Modeling, Analysis and Control Processes of New Energy Power Systems)

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20 pages, 5490 KiB

Open AccessArticle

Transient Stability Analysis of Direct Drive Wind Turbine in DC-Link Voltage Control Timescale during Grid Fault

by Qi Hu, Yiyong Xiong, Chenruiyang Liu, Guangyu Wang and Yanhong Ma

Processes 2022, 10(4), 774; https://doi.org/10.3390/pr10040774 - 15 Apr 2022

Cited by 5 | Viewed by 1954

Abstract

Transient stability during grid fault is experienced differently in modern power systems, especially in wind-turbine-dominated power systems. In this paper, transient behavior and stability issues of a direct drive wind turbine during fault recovery in DC-link voltage control timescale are studied. First, the [...] Read more.

Transient stability during grid fault is experienced differently in modern power systems, especially in wind-turbine-dominated power systems. In this paper, transient behavior and stability issues of a direct drive wind turbine during fault recovery in DC-link voltage control timescale are studied. First, the motion equation model that depicts the phase and amplitude dynamics of internal voltage driven by unbalanced active and reactive power is developed to physically depict transient characteristics of the direct drive wind turbine itself. Considering transient switch control induced by active power climbing, the two-stage model is employed. Based on the motion equation model, transient behavior during fault recovery in a single machine infinite bus system is studied, and the analysis is also divided into two stages: during and after active power climbing. During active power climbing, a novel approximate analytical expression is proposed to clearly reveal the frequency dynamics of the direct drive wind turbine, which is identified as approximate monotonicity at excitation of active power climbing. After active power climbing, large-signal oscillation behavior is concerned. A novel analysis idea combining time-frequency analysis based on Hilbert transform and high order modes is employed to investigate and reveal the nonlinear oscillation, which is characterized by time-varying oscillation frequency and amplitude attenuation ratio. It is found that the nonlinear oscillation and even stability are related closely to the final point during active power climbing. With a large active power climbing rate, the nonlinear oscillation may lose stability. Simulated results based on MATLAB^® are also presented to verify the theoretical analysis. Full article

(This article belongs to the Special Issue Modeling, Analysis and Control Processes of New Energy Power Systems)

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18 pages, 3170 KiB

Open AccessArticle

Optimal Current Allocation Strategy for Hybrid Hierarchical HVDC System with Parallel Operation of High-Voltage and Low-Voltage DC Lines

by Zhichao Yang, Bingtuan Gao and Zeyu Cao

Processes 2022, 10(3), 579; https://doi.org/10.3390/pr10030579 - 16 Mar 2022

Cited by 2 | Viewed by 2500

Abstract

For long-distance and bulk-power delivery of new energy, high-voltage direct current (HVDC) is a more effective way than high-voltage alternative current (HVAC). In view of the current capacity disparity between line commutated converter (LCC) and voltage source converter (VSC), a hybrid hierarchical HVDC [...] Read more.

For long-distance and bulk-power delivery of new energy, high-voltage direct current (HVDC) is a more effective way than high-voltage alternative current (HVAC). In view of the current capacity disparity between line commutated converter (LCC) and voltage source converter (VSC), a hybrid hierarchical HVDC topology with parallel operation of 800 kV and 400 kV DC lines is investigated. The optimal current allocation method for hybrid hierarchical HVDC is proposed distinct from the same rated current command configuration method of high-voltage and low-voltage converters in traditional topology. Considering the transmission loss reduction of the HVDC system, a multi-order fitting function of transmission loss including LCC converter stations, VSC converter stations and DC lines is established. To minimize the transmission loss and the voltage deviation of key DC nodes comprehensively, a multi-objective genetic algorithm and maximum satisfaction method are utilized to obtain the optimal allocation value of rated current command for high-voltage and low-voltage converters. Through the optimization model, an improved constant current controller based on the current allocation strategy is designed. The hybrid hierarchical HVDC system model is built in PSCAD software, and simulation results verify the effectiveness of the proposed topology and optimal current allocation strategy. Full article

(This article belongs to the Special Issue Modeling, Analysis and Control Processes of New Energy Power Systems)

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