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Purpose Permanent magnet (PM) electrical machines are becoming one of the most popular type of the machines used in electrical vehicle drive applications. The main drawback of permanent magnet machines, despite obvious advantages, is associated with the flux control capability, which is limited at high rotor speeds of the machine. This paper aims to present a new arrangement of permanent magnets and flux barriers in the rotor structure to improve the field weakening control of hybrid excited machines. The field weakening characteristics, back-emf waveforms and efficiency maps of this novel machine have been reported. Design/methodology/approach In the study, finite element analysis was used to perform simulation research. Then, based on the simulation studies, an experimental model was built. The paper also presents selected experimental results. Findings Obtained results show that the proposed machine topology and novel control strategy can offer an effective flux control method allowing to extend the maximal rotational speed of the machine at constant power range. Practical implications The proposed solution can be used in electric vehicles drive to extend its torque and speed range. Originality/value The paper presents original design and results of research on a new solution of a hybrid excited machine with magnetic barriers in a rotor.

The paper presents an unconventional approach to control the hybrid excited synchronous machine (HESM), which can be used for drives of pure electric vehicles. The hybrid excitation of the additional control coil placed on the rotor of the machine has been realized by the wireless energy transfer system connected with the rotor shaft. Experimental results of back-EMF characteristics obtained on a prototype of HESM were compared with 3-dimentional finite elements analysis (3D-FEA) predictions. This design, despite some additional complications in the power supply system of the machine, simplifies the mechanical construction and reduces the control coil&rsquo, s losses compared to the construction with the coil placed on the stator.

Propulsion shaft torque measurement is essential in ship energy efficiency evaluation and emission control. Its accuracy and uncertainty influence decision making in terms of voyage optimisation and fuel consumption. For best results, the measuring device should be adjusted and calibrated adequately. This paper analyses the problem of ship propulsion shaft torque meter zero adjustment. Presented results of initial investigation suggest significant unrepeatability of the torque observed when the propulsion unit is at a standstill. Using a recently designed telemetry torque meter and an older analogue device a series of experimental research was conducted on board of a ship and on marine propulsion units installed in a laboratory. A new statistical method for zero adjustment is proposed and evaluated against methods commonly used on ships. The survey results suggest that the new method is burdened with a lower random error compared to presently used methods and uniquely allows for uncertainty evaluation.

Paper describes the system design of modern power electronics laboratory test stands intended for electrical engineering schools and universities. Proposed system design simplifies the configuration of the lab and maximizes the time that the students can use for experimental measurements and converter characterization. System pre-configuration is constant for all exercises so the students do not need to learn the system design of every particular test stand. It also provides clear measurement readings and protection loops so number of errors or damages of the hardware during testing is minimized.

The paper presents the optimization and comparison of different rotor design concepts of an Electrically Controlled Permanent Magnet Excited Synchronous Machine (ECPMSM) possessing a field control capability. The experimental results of a no-load back electromotive force (back-EMF) waveforms, cogging torque and electromagnetic torque values are presented in detail. Moreover, in order to compare the over-speed capability of the machine in the varying rotor designs, the predicted performances, i.e. range of speed and resulting torque of the machines, have been estimated.

Proposed paper presents a fast algorithm for determining static and switching losses of power electronic devices in three-phase DC/AC inverters for different semiconductor materials. This method uses table — form, stored characteristics of individual semiconductor devices, without a necessity of detailed, time resolved analysis of the commutation process. Using such algorithm accelerates total loss calculation, as a result electric machine control strategy can be developed allowing the improvement of the efficiency of the entire propulsion system.

The paper introduces an “a-priori” look-up-table procedure for an efficiency-optimal inverter-machine control system. This method has been applied for a hybrid excited permanent magnet synchronous machine. An exemplary machine model is proposed and a prototype is introduced with stator-located excitation coil. An iterative process for optimal current distribution is described, including multidimensional tables of overall losses and efficiencies. Based on appropriate calculations, an optimization algorithm can be implemented for various target functions, including classic permanent magnet synchronous machines. The proposed approach has been validated using experimental data. Experimental test-bench construction is presented, along with basic discussions on the methodology. Modeling and measurement results are presented, along with corresponding conclusions. A decrease of up to 6% of overall system losses was measured, mostly in the high speed range of the machine.

This paper discussed a control system for an HPMSM machine with a stator based field coil aiming at maximum efficiency of the inverter-machine system. A new procedure for efficiency-optimal inverter-machine propulsion system has been introduced. An iterative process for optimal current distribution is described with multidimensional tables of overall losses and efficiencies. Due to high-speed calculations, optimization algorithm can be implemented for various goal functions including classic PMSM drivetrains.