High Voltage Hybrid Generator and Conversion System for Wind Turbine Applications

This paper presents the design of a high voltage hybrid generator (HG) and conversion system for wind turbine applications. The HG combines wound field (WF) and permanent magnet (PM) rotor excitations. At any given speed, the PM induces a fixed stator voltage while the WF induces a variable controlled stator voltage. The HG alternating output is rectified via a passive rectification stage, hence the machine net DC output voltage is controlled over a prescribed, but limited range. The split ratio between PM and WF rotor sections is considered as varying from a fully WF rotor, or traditional synchronous generator (SG), to some ratio of PM to WF excitation. The turbine operational characteristics and maximum wind velocity variations between turbines in a wind farm are used to define the WF to PM split ratio. Both a 3-phase and a 9-phase stator winding design are investigated. The 9-phase winding results in 4.2% higher output RMS voltage that yields a more power dense solution. It further yields lower rectified DC-link voltage ripple. The HG mass, loss audits and efficiency discussions are presented. In order to investigate the feasibility of the HG concept a small scale laboratory prototype is designed and operational test results presented that show good agreement with the simulation model results

An efficient offshore wind-wave hybrid generation system using direct-drive multitoothed rotating and linear machines

This paper presents an offshore wind-wave hybrid generation (WWHG) system, which can efficiently harness the offshore wind and wave energy. The key is to use the multitoothed doubly-salient permanent-magnet (MDSPM) machines for serving the rotating generator and the linear generator. Different from the traditional wind or wave generation system, this WWHG system integrates the wind generation part and wave generation part together to directly harness the wind and wave energy without gear box. The system configuration and machine design are analyzed and discussed in detail. Also, the finite-element method is performed to verify the validity of the proposed two machine design. The results tell that the system has the high reliability and can be upgraded to the suitable size for offshore hybrid-source energy conversion in practical application. © 2014 IEEE.published_or_final_versio

A comprehensive review on brushless doubly-fed reluctance machine

© 2021 by the authors. Licensee MDPI, Basel, Switzerland. The Brushless Doubly-Fed Reluctance Machine (BDFRM) has been widely investigated in numerous research studies since it is brushless and cageless and there is no winding on the rotor of this emerging machine. This feature leads to several advantages for this machine in comparison with its induction counterpart, i.e., Brushless Doubly-Fed Induction Machine (BDFIM). Less maintenance, less power losses, and also more reliability are the major advantages of BDFRM compared to BDFIM. The design complexity of its reluctance rotor, as well as flux patterns for indirect connection between the two windings mounted on the stator including power winding and control winding, have restricted the development of this machine technology. In the literature, there is not a comprehensive review of the research studies related to BDFRM. In this paper, the previous research studies are reviewed from different points of view, such as operation, design, control, transient model, dynamic model, power factor, Maximum Power Point Tracking (MPPT), and losses. It is revealed that the BDFRM is still evolving since the theoretical results have shown that this machine operates efficiently if it is well-designed

Emerging Multiport Electrical Machines and Systems: Past Developments, Current Challenges, and Future Prospects

Distinct from the conventional machines with only one electrical and one mechanical port, electrical machines featuring multiple electrical/mechanical ports (the so-called multiport electrical machines) provide a compact, flexible, and highly efficient manner to convert and/or transfer energies among different ports. This paper attempts to make a comprehensive overview of the existing multiport topologies, from fundamental characteristics to advanced modeling, analysis, and control, with particular emphasis on the extensively investigated brushless doubly fed machines for highly reliable wind turbines and power split devices for hybrid electric vehicles. A qualitative review approach is mainly adopted, but strong efforts are also made to quantitatively highlight the electromagnetic and control performance. Research challenges are identified, and future trends are discussed

A comprehensive review on brushless doubly-fed reluctance machine

The Brushless Doubly-Fed Reluctance Machine (BDFRM) has been widely investigated in numerous research studies since it is brushless and cageless and there is no winding on the rotor of this emerging machine. This feature leads to several advantages for this machine in comparison with its induction counterpart, i.e., Brushless Doubly-Fed Induction Machine (BDFIM). Less maintenance, less power losses, and also more reliability are the major advantages of BDFRM compared to BDFIM. The design complexity of its reluctance rotor, as well as flux patterns for indirect connection between the two windings mounted on the stator including power winding and control winding, have restricted the development of this machine technology. In the literature, there is not a comprehensive review of the research studies related to BDFRM. In this paper, the previous research studies are reviewed from different points of view, such as operation, design, control, transient model, dynamic model, power factor, Maximum Power Point Tracking (MPPT), and losses. It is revealed that the BDFRM is still evolving since the theoretical results have shown that this machine operates efficiently if it is well-designed

Maximum power point tracking control of a linear magnetic-geared generator for direct-drive wave energy conversion

This paper deals with control of a linear magneticgeared permanent-magnet generator for wave power generation using maximum power point tracking (MPPT) algorithm. Firstly, the linear magnetic-geared permanent-magnet generator structure is presented. The machine modeling is established based on the finite element analysis (FEA). Secondly, by analyzing the dynamic model of the wave power, the MPPT algorithm for directdrive wave power generation is discussed. Then, the performance for maximizing wave power absorption is verified and evaluated by the circuit simulator. The results verify that the MPPT algorithm is valid for the direct-drive wave power generation.postprin

A linear doubly-salient HTS machine for wave energy conversion

This paper proposes a linear doubly-salient high-temperature superconductor (HTS) machine for wave energy conversion, which is composed of a tubular stator and a tubular translator. Since the translator is a simple iron core with salient poles, it is so robust that it can be directly coupled with the reciprocating buoy. The stator consists of an iron core with salient poles, DC HTSfield windings and 3-phase HTS concentrated armature windings. By using the finite element analysis, the proposed machine is quantitatively compared with its permanent magnet and copperwinding counterparts. Hence, it validates that its performance, especially the power density, can be improved greatly. © 2011 IEEE.published_or_final_versio

Modular switched reluctance machines to be used in automotive applications

In the last decades industry, including also that of electrical machines and drives, was pushed near to its limits by the high market demands and fierce competition. As a response to the demanding challenges, improvements were made both in the design and manufacturing of electrical machines and drives. One of the introduced advanced technological solutions was the modular construction. This approach enables on a hand easier and higher productivity manufacturing, and on the other hand fast repairing in exploitation. Switched reluctance machines (SRMs) are very well fitted for modular construction, since the magnetic insulation of the phases is a basic design requirement. The paper is a survey of the main achievements in the field of modular electrical machines, (especially SRMs), setting the focus on the machines designed to be used in automotive applications

Simulation of a linear permanent magnet vernier machine for direct-drive wave power generation

This paper proposes a linear permanent magnet (PM) vernier machine for direct-drive wave power generation. Firstly, the machine structure is proposed and its parameters are indentified by finite element analysis (FEA). Secondly, the mathematical modeling of wave power absorption system was established. The control strategy for maximizing absorbed wave power is discussed. Then, by using Matlab/Simulink, the wave power generator system is modeled and simulated. A vector control scheme is implemented which controls power flow between the generator and the load via a bi-directional AC/DC converter. The simulation results verify the feasibility of the proposed machine used for direct-drive wave power generation. © 2011 IEEE.published_or_final_versionThe 2011 International Conference on Electrical Machines and Systems (ICEMS 2011), Beijing, China, 20-23 August 2011. In Proceedings of ICEMS, 2011, p. 1-