Showing papers by "Chris Gerada published in 2005"
24 Oct 2005
TL;DR: In this article, the effect of different numbers of shorted turns in one coil of the stator winding upon the operation of vector-controlled permanent magnet synchronous machine drives is examined.
Abstract: This paper examines the effect of different numbers of shorted turns in one coil of the stator winding upon the operation of vector-controlled permanent magnet synchronous machine drives. A simple thermal model of the coil is used to examine the duration the fault can be allowed to exist before there is further degradation of the insulation. Simulation results by DMRM incorporate saturation and slotting effects. Short circuit current is difficult to limit due to the uncontrolled permanent magnet produced field. Permanent magnets are also prone to demagnetization due to the compound effect of the demagnetising MMF produced by the high short circuit current together with the armature reaction MMF. Shorting small numbers of turns gives very little time before further failures could occur. Shorts of large numbers of turns change machine flux levels, saturation and torque constant. Part functionality following a winding fault might aid controlled, drive shutdown or keep up operation in intermittent, short duration, load cycles.
46 citations
15 May 2005
TL;DR: In this paper, the authors examined the part functionality of a five phase vector-controlled induction motor drive following a winding fault and found that shorting small numbers of turns gives very little time before further failures could occur.
Abstract: This paper examines part functionality of a five phase vector controlled induction motor drive following a winding fault. The ability of vector controlled induction-motor drives to continue operating with different numbers of shorted turns in one coil of the stator winding is examined. A simple thermal model of the coil is used to examine the duration the fault that can be allowed to exist before there is further degradation of the insulation. Simulation results given by a dynamic mesh reluctance model of the machine incorporate saturation and slotting effects. Shorting small numbers of turns gives very little time before further failures could occur. Shorts of large numbers of turns change machine flux levels, saturation and effective torque constant. By reducing the magnetising current, the short circuit current decreases, the torque developed improves and temperature rise is limited. Part functionality following a winding fault might aid controlled, drive shutdown or provide an idling mode in multi-actuator, aircraft, flight-actuation-systems. This could be particularly helpful with electromechanical actuators
18 citations
24 Oct 2005
TL;DR: Computed results are presented which confirm the potential of the method and support the idea that this type of test may have merit particularly for purposes of checking on quality of production where expensive test facilities are undesirable.
Abstract: The concept of obtaining stray load loss results from a test on an unbalanced motor is examined and its advantages shown. Computed results are presented which confirm the potential of the method. Experimental results also support the idea that this type of test may have merit particularly for purposes of checking on quality of production where expensive test facilities are undesirable.
9 citations
01 Jan 2005
TL;DR: In this article, a dynamic mesh reluctance model (DMRM) is used to model the permanent magnet (PM) machine drive model under vector control, incorporating saturation and slotting effects without the slowness associated with finite element modelling.
Abstract: This paper describes the application of dynamic reluctance mesh modelling techniques to permanent magnet (PM) machine drive modelling The dynamic mesh reluctance model (DMRM) provides a mechanism for analysing the motor performance in significant detail, incorporating saturation and slotting effects without the slowness associated with finite element modelling This allows the integration of the power electronic converter and control algorithms within the machine model thus making it possible to investigate the implications of machine geometry on controlled drive operation Modelling the drive system as a whole helps for optimised machine design for controlled drive operation In this paper a detailed machine magnetic computational model is developed, able to simulate the PM machine's behaviour under vector control A 4 KW PM synchronous machine is modelled using the DMRM and the results are validated using a finite element modelling software
7 citations