This study presents a model-based method for detecting an open-circuit fault in battery supply unit feeding a permanent magnet synchronous motor. Apart from the commonly present DC voltage sensor at converter's input, no additional sensors are required. As a first step, the DC supply system is modelled as a lumped parameter electric circuit. Further, a procedure for estimation of DC supply voltage based on inverter's current and open-circuit battery voltage is proposed. A sliding mode observer is then used to obtain the actual value of open-circuit battery voltage, required by the modelling algorithm. Consequently, an open-circuit fault in a DC supply circuitry is determined based on the analysis of discrepancy between the estimated and measured DC supply voltage. Detection algorithm has been tested on a laboratory setup and its functionality is confirmed by experimental results.

This paper presents magnetic flux density behaviour in laminated electrical sheets which affects the results and precision of iron losses calculation in imbedded permanent magnet (IPM) machine. Objective of the research was to analyse all the influential phenomena that were identified through iron loss models analysis, finite element method simulations and iron loss measurements. The presence of phenomena such as harmonic content and rotational magnetic fields are confirmed with finite element method analysis of concentrated and distributed winding IPM machine. A significant magnetic flux density ripple in the rotor of concentrated winding IPM machine in comparison to distributed winding IPM machine is revealed and analysed. Behaviour that affects iron loss in the rotor of synchronous machines in the absence of first order harmonic is analysed. The DC level added to alternating magnetic flux density was used in experiment to mimic magnetic behaviour on the rotor of IPM machine and further to calculate iron losses.

This paper presents magnetic flux density behaviour in laminated electrical sheets which affects the results and precision of iron losses calculation in imbedded permanent magnet (IPM) machine. Objective of the research was to analyse all the influential phenomena that were identified through iron loss models analysis, finite element method simulations and iron loss measurements. The presence of phenomena such as harmonic content and rotational magnetic fields are confirmed with finite element method analysis of concentrated and distributed winding IPM machine. A significant magnetic flux density ripple in the rotor of concentrated winding IPM machine in comparison to distributed winding IPM machine is revealed and analysed. Behaviour that affects iron loss in the rotor of synchronous machines in the absence of first order harmonic is analysed. The DC level added to alternating magnetic flux density was used in experiment to mimic magnetic behaviour on the rotor of IPM machine and further to calculate iron losses. K e y w o r d s: iron losses, permanent magnet synchronous machine, rotational magnetic flux density, Bertotti model, loss surface model