1,477 research outputs found
Performance estimation of interior permanent-magnet brushless motors using the voltage-driven flux-MMF diagram
The flux-magnetomotive force (flux-MMF) diagram, or "energy conversion loop," is a powerful tool for computing the parameters of saturated interior permanent-magnet brushless motors, especially when the assumptions underlying classical dq theory are not valid, as is often the case in modern practice. Efficient finite-element computation of the flux-MMF diagram is possible when the motor current is known a priori, but in high-speed operation the current regulator can lose control of the current waveform and the computation becomes "voltage-driven" rather than "current-driven." This paper describes an efficient method for estimating the motor performance-average torque, inductances-by solving the voltage-driven problem. It presents experimental validation for a two-pole brushless interior permanent-magnet motor. The paper also discusses the general conditions under which this method is appropriate, and compares the method with alternative approaches
Embedded finite-element solver for computation of brushless permanent-magnet motors
This paper describes the theory underlying the formulation of a âminimum setâ of finite-element solutions to be used in the design and analysis of saturated brushless permanent-magnet motors. The choice of finite-element solutions is described in terms of key points on the fluxâMMF diagram. When the diagram has a regular shape, a huge reduction in finite-element analysis is possible with no loss of accuracy. If the loop is irregular, many more solutions are needed. This paper describes an efficient technique in which a finite-element solver is associated with a classical â -axis circuit model in such a way that the number of finite-element solutions in one electrical half-cycle can be varied between 1 and 360. The finite-element process is used to determine not only the average torque but also the saturated inductances as the rotor rotates
Fault-Tolerant Control of a Flux-switching Permanent Magnet Synchronous Machine
Je jasnĂ©, ĆŸe nejĂșspÄĆĄnÄjĆĄĂ konstrukce zahrnuje postup vĂcefĂĄzovĂ©ho ĆĂzenĂ, ve kterĂ©m kaĆŸdĂĄ fĂĄze mĆŻĆŸe bĂœt povaĆŸovĂĄna za samostatnĂœ modul. Provoz kterĂ©koliv z jednotek musĂ mĂt minimĂĄlnĂ vliv na ostatnĂ, a to tak, ĆŸe v pĆĂpadÄ selhĂĄnĂ jednĂ© jednotky ostatnĂ mohou bĂœt v provozu neovlivnÄny. ModulĂĄrnĂ ĆeĆĄenĂ vyĆŸaduje minimĂĄlnĂ elektrickĂ©, magnetickĂ© a tepelnĂ© ovlivnÄnĂ mezi fĂĄzemi ĆĂzenĂ (mÄniÄe). SynchronnĂ stroje s pulznĂm tokem a permanentnĂmi magnety se jevĂ jako atraktivnĂ typ stroje, jejĂĆŸ pĆednostmi jsou vysokĂœ kroutĂcĂ moment, jednoduchĂĄ a robustnĂ konstrukce rotoru a skuteÄnost, ĆŸe permanentnĂ magnety i cĂvky jsou umĂstÄny spoleÄnÄ na statoru. FS-PMSM jsou pomÄrnÄ novĂ© typy stĆĂdavĂ©ho stroje stator-permanentnĂ magnet, kterĂ© pĆedstavujĂ vĂœznamnĂ© pĆednosti na rozdĂl od konvenÄnĂch rotorĆŻ - velkĂœ kroutĂcĂ moment, vysokĂœ toÄivĂœ moment, v podstatÄ sinusovĂ© zpÄtnĂ© EMF kĆivky, zĂĄroveĆ kompaktnĂ a robustnĂ konstrukce dĂky umĂstÄnĂ magnetĆŻ a vinutĂ kotvy na statoru. SrovnĂĄnĂ vĂœsledkĆŻ mezi FS-PMSM a klasickĂœmi motory na povrchu upevnÄnĂœmi PM (SPM) se stejnĂœmi parametry ukazuje, ĆŸe FS-PMSM vykazuje vÄtĆĄĂ vzduchovĂ© mezery hustoty toku, vyĆĄĆĄĂ toÄivĂœ moment na ztrĂĄty v mÄdi, ale takĂ© vyĆĄĆĄĂ pulzaci dĂky reluktanÄnĂmu momentu. Pro stroje buzenĂ© permanentnĂmi magnety se jednĂĄ o tradiÄnĂ rozpor mezi poĆŸadavkem na vysokĂœ kroutĂcĂ moment pod zĂĄkladnĂ rychlostĂ (oblast konstantnĂho momentu) a provozem nad zĂĄkladnĂ rychlostĂ (oblast konstantnĂho vĂœkonu), zejmĂ©na pro aplikace v hybridnĂch vozidlech. Je pĆedloĆŸena novĂĄ topologie synchronnĂho stroje s permanentnĂmi magnety a spĂnanĂœm tokem odolnĂ©ho proti poruchĂĄm, kterĂĄ je schopnĂĄ provozu bÄhem vinutĂ naprĂĄzdno a zkratovanĂ©ho vinutĂ i poruchĂĄch mÄniÄe. SchĂ©ma je zaloĆŸeno na dvojitÄ vinutĂ©m motoru napĂĄjenĂ©m ze dvou oddÄlenĂœch vektorovÄ ĆĂzenĂœch napÄĆ„ovĂœch zdrojĆŻ. VinutĂ jsou uspoĆĂĄdĂĄna takovĂœm zpĆŻsobem, aby tvoĆila dvÄ nezĂĄvislĂ© a oddÄlenĂ© sady. Simulace a experimentĂĄlnĂ vĂœzkum zpĆesnĂ vĂœkon bÄhem obou scĂ©nĂĄĆĆŻ jak za normĂĄlnĂho provozu, tak za poruch vÄetnÄ zkratovĂœch zĂĄvad a ukĂĄĆŸĂ robustnost pohonu za tÄchto podmĂnek. Tato prĂĄce byla publikovĂĄna v deseti konferenÄnĂch pĆĂspÄvcĂch, dvou Äasopisech a kniĆŸnĂ kapitole, kde byly pĆedstaveny jak topologie pohonu a aplikovanĂĄ ĆĂdĂcĂ schĂ©mata, tak analĂœzy jeho schopnosti odolĂĄvat poruchĂĄm.It has become clear that the most successful design approach involves a multiple phase drive in which each phase may be regarded as a single-module. The operation of any one module must have minimal impact upon the others, so that in the event of that module failing the others can continue to operate unaffected. The modular approach requires that there should be minimal electrical, magnetic and thermal interaction between phases of the drive. Flux-Switching permanent magnet synchronous machines (FS-PMSM) have recently emerged as an attractive machine type virtue of their high torque densities, simple and robust rotor structure and the fact that permanent magnets and coils are both located on the stator. Flux-switching permanent magnet (FS-PMSM) synchronous machines are a relatively new topology of stator PM brushless machine. They exhibit attractive merits including the large torque capability and high torque (power) density, essentially sinusoidal back-EMF waveforms, as well as having a compact and robust structure due to both the location of magnets and armature windings in the stator instead of the rotor as those in the conventional rotor-PM machines. The comparative results between a FS-PMSM and a traditional surface-mounted PM (SPM) motor having the same specifications reveal that FS-PMSM exhibits larger air-gap flux density, higher torque per copper loss, but also a higher torque ripple due to cogging -torque. However, for solely permanent magnets excited machines, it is a traditional contradiction between the requests of high torque capability under the base-speed (constant torque region) and wide speed operation above the base speed (constant power region) especially for hybrid vehicle applications. A novel fault-tolerant FS-PMSM drive topology is presented, which is able to operate during open- and short-circuit winding and converter faults. The scheme is based on a dual winding motor supplied from two separate vector-controlled voltage-sourced inverter drives. The windings are arranged in a way so as to form two independent and isolated sets. Simulation and experimental work will detail the driverâs performance during both healthy- and faulty- scenarios including short-circuit faults and will show the drive robustness to operate in these conditions. The work has been published in ten conference papers, two journal papers and a book chapter, presenting both the topology of the drive and the applied control schemes, as well as analysing the fault-tolerant capabilities of the drive.
Influence of skew and cross-coupling on flux-weakening performance of permanent-magnet brushless AC machines
A method is proposed for predicting the flux-weakening performance of permanent-magnet (PM) brushless ac machines accounting for skew and d-q axis cross-coupling. The method is based on a d-q-axis flux-linkage model, a hybrid 2-D finite-element (FE)-analytical method being used to predict the d- and q-axis inductances. However, it only requires 2-D FE analysis of the magnetic field distribution over a cross section of the machine. The developed method is used to predict the torque-speed characteristic of an interior PM brushless ac machine with one stator slot-pitch skew. This is compared with predictions from a direct FE analysis of the machine and validated by measurements
Low-cost, high-resolution, fault-robust position and speed estimation for PMSM drives operating in safety-critical systems
In this paper it is shown how to obtain a low-cost, high-resolution and fault-robust position sensing system for permanent magnet synchronous motor drives operating in safety-critical systems, by combining high-frequency signal injection with binary Hall-effect sensors. It is shown that the position error signal obtained via high-frequency signal injection can be merged easily into the quantization-harmonic-decoupling vector tracking observer used to process the Hall-effect sensor signals. The resulting algorithm provides accurate, high-resolution estimates of speed and position throughout the entire speed range; compared to state-of-the-art drives using Hall-effect sensors alone, the low speed performance is greatly improved in healthy conditions and also following position sensor faults. It is envisaged that such a sensing system can be successfully used in applications requiring IEC 61508 SIL 3 or ISO 26262 ASIL D compliance, due to its extremely high mean time to failure and to the very fast recovery of the drive following Hall-effect sensor faults at low speeds. Extensive simulation and experimental results are provided on a 3.7 kW permanent magnet drive
Efficiency Optimization and Control of Permanent Magnet Synchronous Brushless Motors in Three-Phase Pulse Width Modulated Voltage Source Inverter Drives
In high performance drives where it is desirable to exploit the usefulness of reluctance torque and machine saliency, permanent magnet synchronous brushless motors are machines of choice. However, speed control of these machines especially in the flux weakening region becomes more complex due to the non-linear coupling among the winding currents as well as the nonlinearity present in the torque. While numerous research efforts in the past have considered control and efficiency improvements of induction motors, and synchronous motors with field windings, research efforts in developing an efficiency optimization and control strategy applicable to all salient-type permanent magnet synchronous brushless motors are still in their infancy.;A traditional control technique that has commonly been employed in efficiency improvement efforts is the stator\u27s zero d-axis current (i ds=0) technique. In this method, the rotor flux is aligned with the direct-axis so that the stator\u27s direct-axis current is zero and the torque becomes a linear function of the stator\u27s quadrature-axis current. Although this method achieves decoupling of winding currents and simplicity of control, it does not fully exploit the use of the machine\u27s saliency and reluctance torque, and is also not well-suited for wide-range load operations. The maximum torque per ampere (MTPA) technique is another less complex technique that has been considered which fully exploits the use of machine saliency with motor torque selected along the geometric curve of minimum-amplitude current space vectors for minimum loss operation. The drawback of the MTPA technique is that it does not provide high efficiency performance for synchronous reluctance motors running at low fractional loads.;In this work, the problem of efficiency optimization in the salient-type permanent magnet synchronous brushless motors is investigated. A machine model which includes the effect of core losses is proposed for developing a loss minimization algorithm that dynamically determines the optimal reference currents and voltages required for minimizing the total electrical losses (copper losses and core losses) within the feasible operating regions imposed by the motor and inverter capacities. The loss minimization strategy is implemented within a speed control loop for a synchronous reluctance motor drive and the effectiveness of the proposed scheme is validated by comparing performances with that of the traditional maximum torque per ampere and stator\u27s zero d-axis current vector control methods. It is shown that the proposed scheme offers the advantages of simplicity and superior performance throughout the entire operating range, and also improves motor efficiency to 96% at full load and full-speed operating condition
Brushless permanent magnet DC and AC motor and synchonous reluctance motor design for racing motorcycles
There is an increasing interest in electric transportation. Most large manufacturers now produce hybrid versions of their popular models and in some countries electric cycles and scooter are now popular. Motor sport is often used to develop technology and in this paper designs for electric racing motorcycles are addressed. These are in-frame motors (rather than hub motors which can affect handling and are not as powerful). Typically 10 to 12 kW-hours of batteries can be carried on the cycle and the batteries are almost exhausted at the end of a race. Therefore very high efficiency over a range of operation is needed, but also the motors need to be compact and have high torque density. This paper examines the use of permanent magnet motors and possible designs. © 2013 IEEE
Comparison and Design Optimization of a Five-Phase Flux-Switching PM Machine for In-Wheel Traction Applications
A comparative study of five-phase outer-rotor flux-switching permanent magnet (FSPM) machines with different topologies for in-wheel traction applications is presented in this paper. Those topologies include double-layer winding, single-layer winding, C-core, and E-core configurations. The electromagnetic performance in the low-speed region, the flux-weakening capability in the high-speed region, and the fault-tolerance capability are all investigated in detail. The results indicate that the E-core FSPM machine has performance advantages. Furthermore, two kinds of E-core FSPM machines with different stator and rotor pole combinations are optimized, respectively. In order to reduce the computational burden during the large-scale optimization process, a mathematical technique is developed based on the concept of computationally efficient finite-element analysis. While a differential evolution algorithm serves as a global search engine to target optimized designs. Subsequently, multiobjective tradeoffs are presented based on a Pareto-set for 20 000 candidate designs. Finally, an optimal design is prototyped, and some experimental results are given to confirm the validity of the simulation results in this paper
- âŠ