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16 pages, 1331 KiB

Open AccessEditor’s ChoiceArticle

Enhanced Reaching-Law-Based Discrete-Time Terminal Sliding Mode Current Control of a Six-Phase Induction Motor

by Yassine Kali, Jorge Rodas, Jesus Doval-Gandoy, Magno Ayala and Osvaldo Gonzalez

Machines 2023, 11(1), 107; https://doi.org/10.3390/machines11010107 - 13 Jan 2023

Cited by 6 | Viewed by 1424

This paper develops an inner stator current controller based on an enhanced reaching-law-based discrete-time terminal sliding mode. The problem of tracking stator currents with high accuracy while ensuring the robustness of a six-phase induction motor in the presence of uncertain electrical parameters and [...] Read more.

This paper develops an inner stator current controller based on an enhanced reaching-law-based discrete-time terminal sliding mode. The problem of tracking stator currents with high accuracy while ensuring the robustness of a six-phase induction motor in the presence of uncertain electrical parameters and unmeasurable states is tackled. The unknown dynamics are approximated by using a time delay estimation method. Then, an enhanced power-reaching law is used to make each stage of the convergence faster. A stability analysis and the system controller’s finite-time convergence are demonstrated in detail. Practical work was conducted on an asymmetrical six-phase induction machine to illustrate the developed discrete approach’s robustness and effectiveness. Full article

(This article belongs to the Special Issue Innovative Applications of Multiphase Machines)

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18 pages, 11291 KiB

Open AccessArticle

A Simplified Model Predictive Control for Asymmetrical Six-Phase Induction Motors That Eliminates the Weighting Factor

by João Serra and Antonio J. Marques Cardoso

Machines 2022, 10(12), 1189; https://doi.org/10.3390/machines10121189 - 08 Dec 2022

Cited by 5 | Viewed by 1443

Abstract

The conventional model predictive control (MPC) is an attractive control scheme for the regulation of multiphase electric drives, since it easily exploits their inherent advantages. However, as the number of phases increases, the MPC’s complexity increases exponentially, posing a high computational burden. Additionally, [...] Read more.

The conventional model predictive control (MPC) is an attractive control scheme for the regulation of multiphase electric drives, since it easily exploits their inherent advantages. However, as the number of phases increases, the MPC’s complexity increases exponentially, posing a high computational burden. Additionally, the MPC still presents other issues related to the weighting factor design in the cost function. Accordingly, this paper proposes a low-complexity hysteresis model predictive current control (HMPCC) that can significantly reduce the computational burden, improve the motor’s performance, and completely avoid the weighting factor design. The proposed method is a hybrid control method, consisting of two distinct controls that complement one another. The hysteresis control is used to reduce the number of iterations per sampling period, thereby reducing the computational effort required to choose the voltage vector that actively produces torque/flux, and nullifying the weighting factor requirement. Finally, the MPC is used to improve the torque and current quality. The effectiveness of the proposed method is verified through experimental data, and the results emphasize the improvement of the proposed HMPCC scheme. Full article

(This article belongs to the Special Issue Innovative Applications of Multiphase Machines)

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15 pages, 3816 KiB

Open AccessArticle

Fault-Tolerant Predictive Current Control of Six-Phase PMSMs with a Single Isolated Neutral Configuration

by Pedro Gonçalves, Sérgio Cruz and André Mendes

Machines 2022, 10(12), 1152; https://doi.org/10.3390/machines10121152 - 02 Dec 2022

Cited by 3 | Viewed by 1173

Abstract

Six-phase machines are increasingly used in safety-critical applications due to their inherent fault-tolerant capabilities. Due to the greater complexity of controlling six-phase machines and the fast dynamics required in safety-critical applications, finite control set model predictive control (FCS-MPC) emerged as an ideal candidate [...] Read more.

Six-phase machines are increasingly used in safety-critical applications due to their inherent fault-tolerant capabilities. Due to the greater complexity of controlling six-phase machines and the fast dynamics required in safety-critical applications, finite control set model predictive control (FCS-MPC) emerged as an ideal candidate for the control of six-phase machines. However, most of the available FCS-MPC strategies only apply to six-phase machines where the two sets of three-phase windings are star-connected with isolated neutral points (2N). Nevertheless, the 2N configuration does not take full advantage of the machine’s capabilities in terms of fault tolerance. Hence, this paper proposes a predictive current control strategy based on virtual vectors for six-phase permanent magnet synchronous (PMSM) drives with a single isolated neutral point (1N) configuration. The proposed method reduces the current harmonic distortion, decreases the copper losses, and is suitable to operate the six-phase drive in fault-tolerant conditions. The included simulation and experimental results demonstrate the good performance obtained with the proposed strategy. Full article

(This article belongs to the Special Issue Innovative Applications of Multiphase Machines)

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20 pages, 2151 KiB

Open AccessEditor’s ChoiceArticle

Dynamic Response in Multiphase Electric Drives: Control Performance and Influencing Factors

by Angel Gonzalez-Prieto, Ignacio González-Prieto, Mario J. Duran and Juan J. Aciego

Machines 2022, 10(10), 866; https://doi.org/10.3390/machines10100866 - 27 Sep 2022

Cited by 4 | Viewed by 1532

Abstract

Speed variable electric drives play a key role in the evolution of electrical mobility. The dynamic performance of these systems is a crucial feature for security purposes. For this reason, a large number of works are focused on identification of the most appropriate [...] Read more.

Speed variable electric drives play a key role in the evolution of electrical mobility. The dynamic performance of these systems is a crucial feature for security purposes. For this reason, a large number of works are focused on identification of the most appropriate control technique to satisfy a transient scenario. In this regard, the dynamic abilities of linear and direct controllers were analysed for three-phase drives. Although some insights about their transient performance were obtained, there are yet some issues to be solved. For instance, speed response was typically omitted, some influencing factors were neglected or the multiphase case was carried out. Considering this information, this work proposes a comparative analysis of the dynamic performance of the most popular regulation strategies for a six-phase electric drive. This study analyses speed, current and voltage responses to achieve an overall view of the system performance. Two concepts were employed to simplify the comprehension of the dynamic behavior of a regulation strategy: reaction time and response capacity. Experimental results are employed to confirm the impact of the different agents on a transient situation. Full article

(This article belongs to the Special Issue Innovative Applications of Multiphase Machines)

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16 pages, 6399 KiB

Open AccessArticle

Power Loss Analysis of a Five-Phase Drive System Using a Synchronous Reluctance Motor and an Indirect Matrix Converter with Reduced Switching Losses

by Kotb B. Tawfiq, Mohamed N. Ibrahim and Peter Sergeant

Machines 2022, 10(9), 738; https://doi.org/10.3390/machines10090738 - 28 Aug 2022

Cited by 6 | Viewed by 1178

Abstract

This paper introduces and analyzes the power losses of a five-phase drive system based on an indirect matrix converter (IMC) and a five-phase synchronous reluctance motor (SynRM). The different loss components in the power converter and the motor have been discussed and analyzed. [...] Read more.

This paper introduces and analyzes the power losses of a five-phase drive system based on an indirect matrix converter (IMC) and a five-phase synchronous reluctance motor (SynRM). The different loss components in the power converter and the motor have been discussed and analyzed. Moreover, a control strategy is applied to decrease the power converter losses and make the system superior to the conventional one. The carrier-based pulse-width-modulation (CBPWM) method is used for this. Through the CBPWM, switching losses are kept as low as possible in this technique by ensuring that the rectifier stage experiences zero current commutation. To achieve this, the rectifier and inverter stages are synchronized so that the commutation in the rectifier stage occurs at the zero vectors of the inverter, which corresponds to a zero DC-link current. The converter will therefore have less switching losses thanks to the rectifier’s null value. Experimental validation has shown the usefulness of the proposed CBPWM in providing lower switching losses in the IMC. Additionally, a comparison of the proposed drive system’s performance with a traditional three-phase SynRM-based inverter will be carried out in the speed and torque control modes. Full article

(This article belongs to the Special Issue Innovative Applications of Multiphase Machines)

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23 pages, 7915 KiB

Open AccessArticle

Calculation of Rotor Harmonic Losses in Multiphase Induction Machines

by Bogdan Brkovic and Milos Jecmenica

Machines 2022, 10(5), 401; https://doi.org/10.3390/machines10050401 - 20 May 2022

Cited by 3 | Viewed by 2371

Abstract

The topic of this paper is the determination of rotor harmonic losses in multiphase machines. Specifically, harmonic losses occur in the rotor winding and core due to higher-order spatial harmonics of the flux density. This phenomenon influences machine parameters and overall performance and [...] Read more.

The topic of this paper is the determination of rotor harmonic losses in multiphase machines. Specifically, harmonic losses occur in the rotor winding and core due to higher-order spatial harmonics of the flux density. This phenomenon influences machine parameters and overall performance and increases temperature rise in parts of the rotor. The flux density distribution is determined by the stator magnetomotive force harmonic content, which is directly related to the winding distribution. A cage-rotor asymmetrical six-phase induction machine is selected for this case study. An analysis of different stator winding topologies and their influence on harmonic losses is presented. A finite element-based method for calculating the contribution of individual stator magnetomotive force harmonics to the rotor losses is developed and described in the paper. The analysis includes scenarios with different phase current waveforms to emphasize the issues specific to the asymmetrical six-phase machine. It is found that the magnetomotive force components generated by non-torque-producing current components contribute significantly to harmonic losses. The obtained results can represent a foundation for optimal stator winding topology selection. This work is intended to motivate the development of new and the modification of existing models to properly include rotor harmonic losses during the design, performance prediction, and control of multiphase machines. Full article

(This article belongs to the Special Issue Innovative Applications of Multiphase Machines)

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13 pages, 1105 KiB

Open AccessArticle

Predictive Control of Multi-Phase Motor for Constant Torque Applications

by Manuel R. Arahal, Federico Barrero, Manuel G. Satué and Daniel R. Ramírez

Machines 2022, 10(3), 211; https://doi.org/10.3390/machines10030211 - 16 Mar 2022

Cited by 4 | Viewed by 1739

Abstract

Constant torque motors are needed for rotary screw compressors that are used for cooling and other applications. In such systems, the torque demanded by the load is approximately the same over the whole range of mechanical speeds. In this paper, the use of [...] Read more.

Constant torque motors are needed for rotary screw compressors that are used for cooling and other applications. In such systems, the torque demanded by the load is approximately the same over the whole range of mechanical speeds. In this paper, the use of multi-phase induction machines is investigated for this type of application. The requirement of low stator current distortion is considered. A scheduled approach is used to provide the best possible tuning for each operating point, similar to the concept of gain scheduling control. Simulations and laboratory tests are used to assess the proposal and compare it with finite-state predictive control. The experiments show that a trade-off situation appears between the ripple content in stator currents in the torque-producing and harmonic planes. As a consequence, the controller tuning appears as an important step. The proposed method considers various figures of merit with cost function tuning, resulting in a scheduled scheme that provides improved results. It is shown that the approach leads to a reduction in current ripple, which is advantageous for this particular application. Full article

(This article belongs to the Special Issue Innovative Applications of Multiphase Machines)

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17 pages, 4224 KiB

Open AccessArticle

Design and Multi-Objective Optimization of a 12-Slot/10-Pole Integrated OBC Using Magnetic Equivalent Circuit Approach

by Mohamed Y. Metwly, Ahmed Hemeida, Ayman S. Abdel-Khalik, Mostafa S. Hamad and Shehab Ahmed

Machines 2021, 9(12), 329; https://doi.org/10.3390/machines9120329 - 01 Dec 2021

Cited by 6 | Viewed by 2217

Abstract

Permanent magnet machines (PMs) equipped with fractional slot concentrated windings (FSCWs) have been preferably proposed for electric vehicle (EV) applications. Moreover, integrated on-board battery chargers (OBCs), which employ the powertrain elements in the charging process, promote the zero-emission future envisaged for transportation through [...] Read more.

Permanent magnet machines (PMs) equipped with fractional slot concentrated windings (FSCWs) have been preferably proposed for electric vehicle (EV) applications. Moreover, integrated on-board battery chargers (OBCs), which employ the powertrain elements in the charging process, promote the zero-emission future envisaged for transportation through the transition to EVs. Based on the available literature, the employed machine, as well as the adopted winding configuration, highly affects the performance of the integrated OBC. However, the optimal design of the FSCW-based PM machine in the charging mode of operation has not been conceived thus far. In this paper, the design and multi-objective optimization of an asymmetrical 12-slot/10-pole integrated OBC based on the efficient magnetic equivalent circuit (MEC) approach are presented, shedding light on machine performance during charging mode. An ‘initial’ surface-mounted PM (SPM) machine is first designed based on the magnetic equivalent circuit (MEC) model. Afterwards, a multi-objective genetic algorithm is utilized to define the optimal machine parameters. Finally, the optimal machine is compared to the ‘initial’ design using finite element (FE) simulations in order to validate the proposed optimization approach and to highlight the performance superiority of the optimal machine over its initial counterpart. Full article

(This article belongs to the Special Issue Innovative Applications of Multiphase Machines)

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Review

Jump to: Research

33 pages, 11485 KiB

Open AccessReview

Power Conversion Techniques Using Multi-Phase Transformer: Configurations, Applications, Issues and Recommendations

by Md Tabrez, Pradip Kumar Sadhu, Molla Shahadat Hossain Lipu, Atif Iqbal, Mohammed Aslam Husain and Shaheer Ansari

Machines 2022, 10(1), 13; https://doi.org/10.3390/machines10010013 - 23 Dec 2021

Cited by 7 | Viewed by 4011

Abstract

Recently, the superiority of multi-phase systems in comparison to three-phase energy systems has been demonstrated with regards to power generation, transmission, distribution, and utilization in particular. Generally, two techniques, specifically semiconductor converter and special transformers (static and passive transformation) have been commonly employed [...] Read more.

Recently, the superiority of multi-phase systems in comparison to three-phase energy systems has been demonstrated with regards to power generation, transmission, distribution, and utilization in particular. Generally, two techniques, specifically semiconductor converter and special transformers (static and passive transformation) have been commonly employed for power generation by utilizing multi-phase systems from the available three-phase power system. The generation of multi-phase power at a fixed frequency by utilizing the static transformation method presents certain advantages compared to semiconductor converters such as reliability, cost-effectiveness, efficiency, and lower total harmonics distortion (THD). Multi-phase transformers are essential to evaluate the parameters of a multi-phase motor, as they require a multi-phase signal that is pure sine wave in nature. However, multi-phase transformers are not suitable for variable frequency applications. Moreover, they have shortcomings with regard to impedance mismatching, the unequal number of turns which lead to inaccurate results in per phase equivalent circuits, which results in an imbalance output in phase voltages and currents. Therefore, this paper aims to investigate multi-phase power transformation from a three-phase system and examine the different static multi-phase transformation techniques. In line with this matter, this study outlines various theories and configurations of transformers, including three-phase to five-, seven-, eleven-, and thirteen-phase transformers. Moreover, the review discusses impedance mismatching, voltage unbalance, and per phase equivalent circuit modeling and fault analysis in multi-phase systems. Moreover, various artificial intelligence-based optimization techniques such as particle swarm optimization (PSO) and the genetic algorithm (GA) are explored to address various existing issues. Finally, the review delivers effective future suggestions that would serve as valuable opportunities, guidelines, and directions for power engineers, industries, and decision-makers to further research on multi-phase transformer improvements towards sustainable operation and management. Full article

(This article belongs to the Special Issue Innovative Applications of Multiphase Machines)

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