This paper proposes a novel concept for an electric generator in which both ac windings and permanent magnets (PMs) are placed in the stator. Concentrated windings with a special pattern and phase coils placed in separate slots are employed. The PMs are positioned in a spoke-type field concentrating arrangement, which provides high flux intensification and enables the use of lower remanence and energy non-rare earth magnets. The rotor is exterior to the stator and has a simple and robust reluctance-type configuration without any active electromagnetic excitation components. The principle of operation is introduced based on the concept of virtual work with closed-form analytical airgap flux density distributions. Initial and parametric design studies were performed using electromagnetic FEA for a 3MW direct-drive wind turbine generator employing PMs of different magnetic remanence and specific energy. Results include indices for the goodness of excitation and the goodness of the electric machine designs; loss; and efficiency estimations, indicating that performance comparable to PM synchronous designs employing expensive and critical supply rare-earth PMs may be achieved with non-rare earth PMs using the proposed configuration.

This paper presents a large-scale multi-objective design optimization for a direct-drive wind turbine generator concept that is based upon an experimentally validated computational model for a small-scale prototype motor of the same type. By integrating an outer reluctance -type rotor and a segmented stator with toroidally wound single-coil modules containing spoke -type PMs, the design optimization aims to minimize losses, active mass, and torque ripple while adhering to a power factor constraint. The AC windings and PMs are positioned in the stator and this concept enhances flux concentration, enabling the use of more affordable high energy non-rare- earth (special type) magnets. The exterior rotor follows a simplified reluctance -type configuration, eliminating active electromagnetic components. The operational principle, described in detail, guides design studies using electromagnetic 2D finite element analysis (FEA), showcasing the potential of this configuration to match rare- earth PM performance, with special type PMs, thus addressing cost and supply challenges. Furthermore, alternative materials including the substitution of aluminum wire for copper wire, have also been investigated in this study. The proposed multi-objective design optimization uses the response surface method (RSM) to initiate the optimization and the results on a 3MW, 15 rpm generator, highlight the benefits of this topology, achieving competitive metrics like goodness, specific thrust, and efficiency without rare- earth permanent magnets.

This paper introduces a new motor design for traction applications that achieves high power density and meets the power density target of 50kW/L target set by the US Department of Energy. The proposed motor has a doubly salient structure with concentrated toroidal 3-phase windings and permanent magnets (PMs) in the stator and a reluctance rotor, improves torque capability and operating speed compared to traditional designs. A design optimization process was conducted to balance efficiency, power density, and power factor. An equivalent circuit in the DQ reference frame is introduced to enable vector control for the proposed special double salient machine. The resulting design was validated through the creation of an open frame lab prototype (OFLP) and an experimental dyno test bench was developed. The prototype was tested through open circuit tests, static torque tests, and unity power factor tests. This paper also discusses the use of synchronous reference frame theory and per-phase diagrams to calculate electric machine parameters. In addition to experimentation, 3D and 2D electromagnetic FEA simulations have been performed for unity power factor operation as a generator to numerically separate the power loss components.

Electric power systems have experienced large increases in the number of intelligent, connected and controllable devices being deployed, leading to a high degree of distributed intelligence at the grid-edge. These devices, both utility-owned and consumer-owned, include renewable generation, energy storage, remote switches, voltage regulators, and smart controllable loads. These new devices provide significant potential for increased operational flexibility that can be leveraged to achieve system reconfiguration, resiliency improvements, power quality improvements, and distribution system automation. However, two significant challenges must be addressed before these assets can be leveraged for operations: interoperability and system level validation prior to deployment. Because of the complexity of distributed control systems, and their interactions with legacy centralized controls, a purely simulations-based approach for pre-deployment validation is not sufficient. It requires hardware-in-the-loop (HIL) testing to emulate hardware devices and evaluate their performance. Additionally, securely integrating multiple test facilities at utility operators and vendors can enable the rapid scale-up of evaluation platforms and remove the need for multiple expensive standalone installations. Presented in this paper, is the development of a multi-site evaluation platform that employs Advanced Distribution Management Systems (ADMS), distributed control devices, real-time HIL assets, secure communication links, and protocol adapters. The testbed has been developed at three sites, with one site hosting the ADMS and the other two hosting HIL capabilities. This platform uses standards-based approaches and open-source tools, and hence can serve as a template for other researchers and institutions to implement their multi-site evaluation frameworks for pre-deployment testing.

This paper introduces an innovative design for a synchronous electric motor that has phase coils and permanent magnets (PM) embedded in the stator. The electric machine contains both concentrated winded phase coils in dedicated slots and spoke-type permanent magnets solely in the stator. The spoke-type magnet arrangement achieves a high flux intensity even with low remanence non-rare earth permanent magnets. As the rotor has no active electromagnetic components, the risk for demagnetization is reduced and advanced cooling applied to the stator can enable high-speed operation. The principle of operation and polarity of the motor are investigated with a unique approach including analytical flux density analysis and piece-wise computational modeling. A design optimization is performed for a 100 kW motor at a speed of 3000 rpm, which is typical for industrial applications. The conflicting objectives of active material cost and motor losses are considered using both rare-earth and non-rare-earth ferrite PMs in the inner and outer rotor configurations of the proposed motor topology. Discussions on the trade-off between conflicting objectives, a specific EV motor design using ferrites, as well as alternative manufacturing, considering achievable slot fill factor (SFF) and choice of steel are also presented. Furthermore, an open-frame lab prototype (OFLP) of the proposed motor topology is constructed and tested to validate the principle of operation and design optimization approach, with due consideration to manufacturing.