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A new switched-reluctance machine (SRM) topology with combined rotary and reciprocating rectilinear movement is introduced in this paper. The topology of this machine is based on the conventional radial-flux SRM with a modified rotor structure. Unlike the other rotary-translational electromechanical systems which have separate units, one for rotary motion and another for translational reciprocating motion, the proposed machine achieves combined rotary-reciprocating (RR) movement with just one set of stator coils around each pole identical to the conventional SRM. By exciting each pole of the stator, both radial and axial magnetic flux will be produced in the air gap of the machine. As a result, the electromagnetic reluctance torque around the axis of the rotation and the reluctance force along the axis of translational movement are produced. Details of the rotor structure and machine operation are presented. Magnetic equivalent circuit (MEC) analytical equations are derived for four operational points within the RR motion cycle. Finite-element analysis (FEA) is utilized to validate the analytical MEC equations. The output performance profiles are simulated for two example machines using static 3-D FEA to investigate the impact of the axial displacement of the consequent poles. In addition, a sensitivity analysis is carried out to investigate the impact of the rotor pole angle on the torque and force production of the machine. The dynamic behavior of the proposed structure is analyzed and discussed for two displacements of the consequent axially shifted poles. [ABSTRACT FROM PUBLISHER]

This paper describes the modeling, optimization, mechanical design, and experimental characterization of a high power density wound field synchronous machine (WFSM) for electric vehicle traction applications. The WFSM is designed for brushless rotor field excitation using an axial flux hydrodynamic capacitive power coupler (CPC). The flexible design environment, which was used for large-scale multiobjective optimization of the WFSM, is described. A prototype WFSM, spray cooled with automatic transmission fluid, with an 80-kW output at a base speed of 4000 r/min has been tested. The prototyped WFSM achieves volumetric torque and power densities of 17.22 N·m/L and 7.19 kW/L referred to the envelope cylindrical volume of the active materials plus spray cooling rings. The specific torque and power densities are 4.69 N·m/kg and 1.95 kW/kg referred to the mass of the active materials and the shaft. The prototyped CPC provided up to 1-kW excitation power with a mass 600 g and volume of 0.271 L. [ABSTRACT FROM AUTHOR]

This paper presents a deadbeat-direct torque and flux controller for wound field synchronous machines (WFSMs) without damper/amortisseur windings. Compared to induction machines (IMs) or interior permanent magnet synchronous machines (IPMSMs), WFSMs have an additional degree of freedom through variable field excitation. Discrete time current and flux linkage observers are derived, which model the dynamics and cross coupling introduced by the variable field excitation. The variable field excitation also allows the torque line for the desired change in torque to be shifted on a sample by sample basis compared to IMs or IPMSMs where the torque line is static. This provides the opportunity to actively distribute the transient torque between the rotor and stator windings. A field flux linkage command is derived to achieve unity displacement power factor in the steady state. Experimental results are presented to demonstrate decoupled torque and flux linkage control. [ABSTRACT FROM PUBLISHER]

This paper describes the design and experimental evaluation of two high-efficiency interior permanent-magnet (IPM) motors for use in a commercial transcritical \CO2 (R-744) heat pump water heater (HPWH). Two IPM topologies, a 36-slot 6-pole topology and a 9-slot 6-pole topology, were selected, optimized, and prototyped using a common flat-bar IPM rotor. The experimental analysis includes standard measurements of electrical machine parameters, and dynamometer tests. The initial measurements of the \CO2 compressor performance with a stock line-fed induction machine and the 36-slot 6-pole IPM configuration have been completed. This paper finds a small isentropic compressor efficiency improvement from using the 36-slot 6-pole IPM motor compared to the stock line-fed induction machine at rated operating conditions (essentially constant speed). This paper also expands the open literature on the impact of high-efficiency motor drives on \CO2 compressor operation and \CO2 HPWH systems. [ABSTRACT FROM AUTHOR]

The behavior of rotor eccentricities in current-regulated interior-permanent-magnet machines is investigated. The study focuses on two typical topologies of significant industrial relevance: machines with distributed windings with two slots per pole and phase and motors with concentrated coils and three slots per pole pair. The effect of stator-winding parallel paths is examined for both cases. Coil and terminal electrical quantities and radial forces were simulated using finite-element analysis. Unbalanced operation, where the currents are not equal in parallel phase connections due to eccentricity, is also investigated. Experimental measurements of electrical quantities and forces on motors with static eccentricity are carried out using two special test setups. The experimental measurements validated the simulation results. [ABSTRACT FROM AUTHOR]