Per Sandholdt

DTFC-SVM motion-sensorless control of a PM-assisted reluctance synchronous machine as starter-alternator for hybrid electric vehicles

Permanent magnet-assisted reluctance synchronous machine (PM-RSM) starter alternator systems are credited with good performance for wide speed range in hybrid electric vehicles. This paper proposes a motion-sensorless motor/generator control of PM-RSM from zero speed up to maximum speed, using direct torque and flux control with space vector modulation. A quasioptimal stator flux reference with a flux versus torque functional is proposed. A stator flux observer in wide speed range uses combined voltage-current models for low speeds, and only the voltage model for medium to high speeds, both in proportional-integral closed loop. A novel rotor speed and position observer with a fusion strategy employs signal injection and only one D-module vector filter in stator reference for low speed, combined with a speed observer from the stator flux vector estimation-for medium-high speed. The proposed system is introduced piece by piece and then implemented on a dSpace 1103 control board with a 350-A metal-oxide-semiconductor field-effect transistor-pulse-width modulation converter connected to a 42-Vdc, 55-Ah battery, and a 140-Nm peak torque PM-RSM. Extensive experimental results from very low speed to high speed, regarding observers and drive responses, including artificial loading (motoring and generating), seem very encouraging for future starter-alternator systems

Modeling and power factor analysis of a single phase surface mounted permanent magnet transverse flux machine

Based on the basic principles of a single phase surface mounted permanent magnet transverse flux machine, a model is proposed for predicting its steady state performance including saturation and demagnetization effects. It is shown that by introducing a so called equivalent PM current and due to the natural of nonsalient rotor core, the model could have a very compact expression and high accuracy is guaranteed. The model is verified for steady state using a laboratory prototype. The characteristics of the power factor, which are of great interest for transverse flux machines, are also analyzed and the results are verified by experiment.

Modelling a single phase surface mounted permanent magnet transverse flux machine based on Fourier series method

The transverse flux machine provides a new option for high torque-density drives. Due to the special structure of this kind of machine, the method used to analyse the performance of conventional PM machines should be modified to accommodate the construction of the transverse flux machine. In this paper, the back EMF waveform of a single phase, surface mounted, PM transverse flux machine is analysed based on the Fourier series representation of the equivalent PM magneto-motive force distribution function. Using this method, only one 3D FE model for the aligned position would be enough for calculating the flux linkages for all the other rotor positions and the theory behind the EMF generation for Surface Mounted PM transverse flux machine becomes more apparent. An equivalent circuit model is then proposed for describing the steady state performance based on the EMF waveform analysis. The model is validated using a laboratory prototype.

General torque equation capable of including saturation effects for a single phase surface mounted permanent magnet transverse flux machine

In this paper, based on the electromechanical energy conversion theory, a general analytical torque equation is proposed for calculating the interaction torque produced by the electric and magnetic loading of a single-phase surface mounted permanent magnet transverse flux machine. This equation is valid in both non-saturated and saturated regions, allows any kind of armature current waveforms and there are almost no assumptions needed. Only one measurement of the flux linkage vs. current curve at an arbitrary rotor position is needed for using this equation. The method used in deducing the torque equation is applicable to any other permanent magnet non-salient synchronous machine. It is shown that the general torque equation can have a very compact form and its physical meaning is apparent. The predicted results by this torque equation are verified using a laboratory prototype. Keywords--Torque equation, saturation effects, surface mounted, permanent magnet, transverse flux machine

A simple method to estimate inductance profile of a surface mounted permanent magnet transverse flux machine

The inductance profile plays an essential role in the verification of the design and performance of permanent magnet machines. Various inductance measurement methods have been widely introduced and discussed for permanent magnet machines and switched reluctance motors. These methods have something in common and some of the measurement methods for switched reluctance motors are also suited for the inductance measurement of permanent magnet machines. In this paper, based on the present methods, a simple but accurate method is introduced for measuring the nonlinear inductance profile of permanent magnet machines. A single phase surface mounted permanent magnet transverse flux machine is chosen as an application example due to its simple single-phase structure with concentrated winding, which may simplify the analysis and make the proposed method more straightforward. The proposed method is verified by experiment and compared with 3D FEM result.

A Test and Measurement System for Test of Electrical Drive Systems

A general test and measurement system for electrical drive systems, is presented. This paper describes the test and measurement system, data acquisition, the load emulation capabilities. Experimental results from load torque emulation and sample tests are given.