Avo Reinap

Performance and efficiency evaluation of FPGA controlled IPMSM under dynamic loading

This paper presents an improved synthetic loading method to measure the performance of an interior permanent magnet synchronous machine (IPMSM). A complete analysis of torque-, flux-, and efficiency-maps are done by means of a vector controlled drive implemented with in a field programmable gate array (FPGA). The measurements are compared to results from Finite Element Analysis (FEA). A key feature of this implementation is an instantaneous measurement of the inverter output voltage that facilitates estimation of the input power of the machine. The synthetic loading technique completely eliminates the need for a torque transducer, load machine and holds a control over temperature development during the tests. Simulation and experimental results demonstrate that the supply tracking together with synthetic loading technique is very useful tool to evaluate the efficiency of IPMSM.

Thermal properties on high fill factor electrical windings: Infiltrated vs non infiltrated

This paper presents a comparison of the thermal properties between infiltrated and non-infiltrated copper windings. The focus is on thermal conductivity in the radial direction on the winding. The samples have a fill factor above 65 % due to the manufacturing method of the samples. Samples are produced and measured with the transient plane source technique and then compared to FEM simulations and the Hashin and Shtrikman approximation. The results show a considerable difference between a non-infiltrated and an infiltrated winding, as well as a good agreement between measurements, FEM simulations and the Hashin and Shtrikman approximation.

Design, optimization and construction of an electric motor for an Electric Rear Wheel Drive unit application for a hybrid passenger car

An Electric Rear Wheel Drive -ERWD- unit is a cost effective solution for the electrification of passenger cars. While the conventional front-wheel transmission is kept, the ERWD unit provides electrical torque to the rear wheels and regenerative braking capabilities. In this article the design, optimization, construction and testing of an electric motor for such unit is presented. The experimental test results are compared to the FE simulation results from the design stage in order to validate the design tool.

Dynamic evaluation of the overloading potential of a convection cooled permanent magnet synchronous motor

In order to obtain the maximum efficiency from a hybrid driveline it is crucial to optimize the power distribution between the electric drive and the internal combustion engine. An accurate estimation of how much electric power can be delivered at any instant of time is therefore of great interest. Such estimation is dependent on several factors, as the state of charge of the battery, the temperature and the cooling conditions of the motor and the power electronics at that particular moment. This article proposes a method for evaluating the overloading potential of the electric drive dynamically at any time, based on a previously developed thermal model. Alternative modelling techniques are discussed and the resulting thermal model is validated against experimental measurements.

Dynamic Thermal Modeling and Application of Electrical Machine in Hybrid Drives

This paper presents a holistic view of thermal modeling for an electrical machine used in a Hybrid Electrical Vehicle (HEV). This interconnected system model focuses on the thermal assessment of an electrical machine in a HEV application and estimates the time to failure of the machine depending on the construction of the insulation system and the exploitation of the machine. A transient thermal model of the machine is made as a Lumped Parameter Model (LPM) based on dimensions, material properties and Finite Element Analysis (FEA) determining the power loss model and Computational Fluid Dynamics (CFD) cooling model. The LPM thermal model is compared to measurements and later used in a vehicle powertrain model. Based on the verified thermal model, the estimation of the winding temperature in the machine over different driving cycles is used to predict the thermal degradations of the main insulation and the thermal lifetime of the machine.

Impact of Soft Magnetic Material on Construction of Radial Flux Electrical Machines

Electrical machines with distributed concentrated windings are challenging the selection of the soft magnetic materials due to stator design and power conversion efficiency. A shorter magnetization path and relatively high magnetization frequency is beneficial for low-permeability soft magnetic materials with low power losses in the core. In this paper, a three-phase machine with laminated and iron powder cores is analyzed with focus on a modular winding design, the torque capability, and the stator energy conversion efficiency. Different iron powder cores are compared to a laminated core using 2-D finite element analysis (FEA). The three-phase machine torque is compared among a conventional distributed concentrated winding, an axially distributed wave-winding, and a number of circumferentially distributed wave-winding segments. According to 3-D FEA, the conventional coils are preferred if the permeability of the core is low.

Development of a radial flux machine design environment

This paper focuses on the development of a machine design environment for numeric modelling and analysis of radial flux machines. The design environment is based on Matlab/(Octave) environment, which calls numeric field analysis by FEMM/(Opera-2D). The analysis tool is intended for educational purposes; however it has proved to be a powerful research tool especially at early design stages.

Heat transfer analysis of a traction machine with directly cooled laminated windings

A directly enhanced cooled winding in an electrical traction machine has the potential to extend the operation range, which is in particular attractive for a traction application when operating near peak power for extended periods of time. This paper presents the heat transfer analysis of a modular machine segment with a laminated winding. The laminated winding has a great potential when it comes to production of the winding and the thermal management of the excessive power losses in the winding. The prototype is built and assessed based on experimental measurements and finite element analysis. The results indicate some practical challenges of integrating the combined heat exchanger and winding and controlling the coolant flow through the machine construction. The prototype machine shows a limited enhanced cooling capability mostly due to flow leakage while the results from the simulation models indicate the great potential of direct cooled windings.

Sub-Optimization of a Claw-Pole Structure According to Material Properties of Soft Magnetic Materials

The focus of this paper is on the development of a single phase PM machine with wave-windings where the design variables are the winding layout and design of a soft magnetic powder core for a stator. A number of BH curves are synthesized in order to characterize some of the existing powder cores and to study the influence of magnetic permeability on starting torque and mean driving torque. The goal of the wave-winding design is to increase the material utilization factor and minimize the resistive power losses in the winding of a radial-to-transversal flux machine with an iron powder core. The outcomes of this paper is a 3D FE magnetic analysis of a number of suggested stator layouts supported with a rapid prototype with a dummy coil.

Evaluation of a semi claw-pole machine with SM 2 C core

New development in material and production technology influences the design of electrical machines. This paper presents a theoretical calculation and experimental verification of a single-phase semi claw-pole machine, which core is made of Soft Magnetic Mouldable Composite - SM2C. In comparison with a conventional claw-pole configuration the semi-claw pole machine has a higher torque capability. This is due to a slightly increased winding arrangement.