High Speed PM Motor Research Articles

AC Copper Loss Evaluation Method for High-Speed PM Motors with Rectangular Coils

AC Copper Loss Evaluation Method for High-Speed PM Motors with Rectangular Coils

Comprehensive Performance Analysis of High-Speed PM Motors With Layered Rotor Structures

Comprehensive Performance Analysis of High-Speed PM Motors With Layered Rotor Structures

Design and Analysis of the High-Speed Permanent Magnet Motors: A Review on the State of the Art

This paper provides an overview of the design and analysis of high-speed PM motors by focusing on prominent issues such as motor losses, temperature rise, rotor strength and vibration. The design challenges of high-speed PM motors are briefly described, and the application of various stator and rotor structures and materials is presented in electromagnetic design. Combined with the temperature distribution of the motor, various heat dissipation measures to suppress the temperature rise are summarized. Strength and dynamics analysis of the rotor are outlined with respect to the safety of rotor operation. The current status of coupled multi-physics domain design used to improve the comprehensive design capability of high-speed PM motors is reviewed. Future directions of technologies related to the design of high-speed PM motors are pointed out.

Outer-Rotor-type High-Speed PM motor with Segmented-shaped Rotor

Outer-Rotor-type High-Speed PM motor with Segmented-shaped Rotor

Prototype Tests of Outer-Rotor-type High-Speed PM Motor

Prototype Tests of Outer-Rotor-type High-Speed PM Motor

Design and Performance Investigation of 3-Slot/2-Pole High Speed Permanent Magnet Machine

High-speed rotating mechanical machinery is a developed, mature and reliable technology for many engineering applications. In high-speed permanent magnet machines, the rotor's permanent magnet PM is not strong enough to withstand the centrifugal force resulting from excessive rotational speed; thus, the PM material must be protected by a non-magnetic alloy sleeve. This paper presents a novel high-speed PM machine with solid rotor PM covered by a titanium retaining sleeve. The rotor stress condition is simplified as a plane stress problem according to the strength measurement of solid PM rotors in the high-speed PM motors. The analytical formulas for rotor stress are presented based on the polar coordinate displacement method. The proposed model is compared with a conventional model having auxiliary slots in stator teeth. Using a finite element analysis environment, the performance analysis shows that the proposed design has reduced magnet eddy current loss, cogging torque, and iron losses. The initial design is also optimized using a deterministic optimization algorithm that increases output torque by 26% compared to the initial design.

Efficiency Improvement of Outer-Rotor-type High-Speed PM Motor

Efficiency Improvement of Outer-Rotor-type High-Speed PM Motor

Reduction of Rotor Harmonic Eddy-Current Loss of High-Speed PM BLDC Motors by Using a Split-Phase Winding Method

Low-order harmonic currents in high-speed permanent magnet brushless dc (PM BLDC) motors cause large rotor eddy-current loss, resulting in high temperature rise and even overheating in the rotors, thus their application in the field of high-speed drive is limited. The rotor eddy-current loss can be reduced by using a split-phase winding method. In this paper, various time–space orders of harmonic eddy-current losses in the rotors of the PM motors with and without split-phase winding are quantified. The calculated results indicate that the rotor harmonic eddy-current losses generated by the low-order harmonic currents, which inherently exist in PM BLDC motors, are greatly reduced. Furthermore, associated with the characteristics of harmonic currents of PM BLDC motors, the mechanism of drastically reducing the rotor harmonic eddy-current loss of high-speed PM motors by using the split-phase winding method is revealed and experimentally validated.

Effects of Teeth Length and Magnet Material on Characteristics and Effects on Conductor Eddy Current Loss due to Changes in the number of Strands of Litz Wire of Low Voltage Drive High-Speed Motorp

High-speed motor driven in low voltage are used in equipment such as electric reel and handy vacuum cleaner. If a motor with a general structure used in an operating range of several thousand revolutions is used as it is in a high-speed range of several tens of thousands of revolutions, efficiency will decrease due to a large amount of iron loss. In this paper, we proposed models in which the stator teeth length and the magnet material were changed in order to suppress the iron loss that causes the efficiency reduction of the high-speed PM motor. In this case, since the eddy current loss occurs in the armature conductor, the effect of reducing the conductor eddy current loss by using the Litz wire was also examined. As a result, it was shown that the proposed model improves the efficiency compared to the conventional structure.

Mini Screw: the development of a high-CFM compact compressor for LGWP A1 low pressure refrigerant

Addressing global warming concerns is one of the largest challenges facing the HVAC industry currently. Although A2L refrigerants are important options to consider for certain sizes of HVAC units, there remain many systems that require A1 category refrigerants. Among the several available refrigerants, we looked at DR-12 as one of the attractive refrigerants. Along with it being in the A1 category, its very low GWP value (32) and high cycle performance make it an excellent long-term solution if successfully applied. A significant challenge to overcome with this refrigerant is its low density. DR-12 will require almost 7 times the volumetric flow for the same cooling capacity compared to R410A. The current scroll or rotary technologies are not realistic to be applied in such a low density refrigerant system. The development of a new compact large CFM compressor is key to realize the scope of the project successfully. The authors have explored various types of compression mechanisms and identified screw as one of the most suited technologies for this refrigerant. In order to obtain such large volume flow (19.8L/s, 42CFM), a unique screw rotor design and a high speed PM motor were employed. Innovative bearing design and new compressor layout also enabled the compressor to be compact (cϕ145mm) and cost effective. A prototype compressor was built and tested. This concept delivered 17.6kW (5 ton) capacity at 11,000rpm and 4.4kW (1.25 ton) at 2,500rpm, meeting its target requirements. This paper will introduce details of the compressor concept, along with the test results from a physical prototype.

A Novel Sensorless Rotor Position Detection Method for High-Speed Surface PM Motors in a Wide Speed Range

In order to improve the performance of surface permanent magnet synchronous motor drives, a novel sensorless drive scheme is proposed in this paper, which is based on the virtual third-harmonic back EMF incorporating a fractional-N phase-locked loop (FN-PLL) and a synchronous frequency-extract filter (SFF). A simple low-pass filter based circuit is used to obtain the commutation points through the virtual third-harmonic back EMF. After that, an FN-PLL is applied to obtain continuous rotor position angles. On this basis, the SFF-based compensation is proposed to compensate the detecting error adaptively. Meanwhile, the field vector control loop for surface PM motor is proposed, which is based on the proposed rotor position detection link and compensation link. An experimental high-speed magnetically suspended blower platform is built. The effectiveness and the feasibility of the proposed method are validated with experimental results.

Design Procedure for High-Speed PM Motors Aided by Optimization Algorithms

This paper considers the electromagnetic and structural co-design of superficial permanent magnet synchronous machines for high-speed applications, with the aid of a Pareto optimization procedure. The aim of this work is to present a design procedure for the afore-mentioned machines that relies on the combined used of optimization algorithms and finite element analysis. The proposed approach allows easy analysis of the results and a lowering of the computational burden. The proposed design method is presented through a practical example starting from the specifications of an aeronautical actuator. The design procedure is based on static finite element simulations for electromagnetic analysis and on analytical formulas for structural design. The final results are validated through detailed transient finite element analysis to verify both electromagnetic and structural performance. The step-by-step presentation of the proposed design methodology allows the reader to easily adapt it to different specifications. Finally, a comparison between a distributed-winding (24 slots) and a concentrated-winding (6 slots) machine is presented demonstrating the advantages of the former winding arrangement for high-speed applications.

Robust Optimization of High-Speed PM Motor Design

This paper proposes a robust optimization algorithm, enabling global optimum tracking and manufacturing uncertainty factors handling, for high-speed permanent magnet motor design. A new robustness criterion is introduced, considering effectively the impact of the construction tooling uncertainties on the design variables in all objectives. An adaptive-network-based fuzzy inference system is adopted acting as a surrogate for the time-consuming finite-element (FE) analyses and results in computationally fast robust electric machine design procedure. The procedure has been validated through FE high-speed motor design.

A Novel Flux-Weakening Structure of High-Speed Permanent Magnet Motor Based on the Soft Ferrite

Soft ferrite has the characteristics of high permeability, high resistivity, low loss. Based on this, a new flux-weakening structure of high-speed permanent magnet motor was presented. The structure relies on changing the saturation of soft magnetic ferrite to change the equivalent magnetic resistance of permanent magnet magnetic circuit in the motor, so the main flux of the permanent magnet motor can be reduced. By the 3D Finite Element analyses, the magnetic field distribution characters in the air gap can be pointed out. The analysis results prove the flux-weakening method is presented in this paper is correct and feasible. It can provide a practical flux-weakening method of the high-speed PM motor.

Analysis of a Novel Flux-Weakening Structure of High-Speed Permanent-Magnet Motors Based on Soft-Magnetic Ferrite

Soft-magnetic ferrite has advantages of high initial magnetic permeability, high electric resistivity, low loss and low cost in the high-frequency alternating field. Considering the characters of soft-magnetic ferrite, this paper uses a soft-magnetic ferrite ring as stator core and presents a novel field-weakening structure of high speed PM motors. Based on this structure, a novel field-weakening method of PM motors can be presented. The equivalent reluctance of permanent magnetic field circuit can be changed by altering saturation degree of soft-magnetic ferrite core in this method. For the convenience of analysis and calculation, considering the magnetic field distribution in the motors, this paper deduces an equivalent two-dimensional finite element model of three-dimensional magnetic field, by which the field-weakening parameters of high speed PM motor can be conveniently analyzed. The simulation results of finite element model prove: the field-weakening structure of high speed PM motor based on soft-magnetic ferrite, presented in this paper, is valid and feasible, offers a valid and applicative method for field-weakening control of high speed PM motor.

Discussion of "A super high speed PM motor drive system by a quasi-current source inverter" [and reply

The author argues that the paper A super high speed PM motor drive system by a quasi-current source inverter by Takahashi et. al. (see ibid., vol.30, no.3, 1994) does not prove the authors' hypothesis that the PM motor air gap length has an effect on its losses. The authors reply to this argument and provide additional analytical data in an effort to verify their proposed method of reducing PM motor slot ripples. >

A super high speed PM motor drive system by a quasi-current source inverter

This paper describes a surface mounted PM motor with the ratings of 5 kW and 150000 RPM for super high speed drive applications such as a machine tool. A much larger air gap, compared with that of the existing PM motors, is utilized to reduce the slot ripples and hence the resultant eddy current loss in the metallic sleeve that retains the permanent magnets, otherwise this loss would be objectionable at such high speeds. The motor is supplied from a quasi-current source inverter with the DC current controlled by a chopper and operated at a near unity power factor by the use of a simple position sensor-less control, to improve the motor efficiency. The analytic results are presented to show the slot ripple reducing effect of increasing the air gap length. To investigate the losses of the sleeve, several motors with different sleeves were manufactured and tested. Typical experimental results on these prototypes are given, which show that motor efficiency of higher than 90% can be realized at the rated torque over a wide speed range.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>