Hybrid less rare-earth synchronous reluctance motors (HLR-SRMs) feature complex magnetic circuits that render back-electromotive force (back-EMF) optimization challenging, leading to torque ripple and reduced voltage utilization. This paper introduces an analytical model-based particle swarm optimization (PSO) scheme to minimize back-EMF harmonics by employing flux barrier angles as optimization variables. Analysis demonstrates that suppressing targeted orders of no-load slotless air-gap flux density harmonics is essential for enhancing back EMF performance. A simplified analytical model for the HLR SRM is developed to enable rapid calculation of the air-gap flux density. Leveraging the multi-segment distribution characteristics of the model's air-gap flux density, optimization targets the modulation of flux barrier angles to attenuate specific harmonics By minimizing dependence on finite element analysis (FEA), the proposed model-based PSO achieves efficient multi-step iterations while maintaining accuracy, thereby avoiding trapped in local optima and significantly reduces computational resource consumption. FEA and experimental validation on a prototype motor confirm the efficacy of the proposed algorithm in reducing the total harmonic distortion (THD) of the back-EMF.

The closed-loop bandwidth of permanent magnet synchronous motor (PMSM) drives is severely constrained by stability requirements under high-speed, low switching-to-fundamental-frequency ratio (SFR) operation. To overcome this limitation, this article proposes an enhanced digital current controller based on complex pole placement with active decoupling for high-speed PMSM. The distribution pattern of poles in the internal model control (IMC) system is revealed. It is theoretically validated that, within the IMC framework, the enhancement of the current loop bandwidth and the maintenance of closed-loop stability are mutually restrictive and cannot be independently regulated. By constructing a damping modulation loop and embedding the complex pole placement with active decoupling function into the forward path, targeted regulation of the low-damping poles in the control system is achieved. This enables the proposed controller to possess the capability for coordinated regulation of the current loop gain and the dominant closed-loop poles. Comprehensive performance evaluation of the proposed control strategy is conducted on an experimental prototype. The proposed control system maintains robust high-speed operation even under extreme conditions with an SFR as low as 10. Furthermore, it achieves a synergistic enhancement in both dynamic response and disturbance rejection across a wide speed range from 0 to 60 000 r/min.

When a permanent magnet synchronous motor (PMSM) operates at high speed with a low carrier frequency ratio (CFR), current coupling and control delay can severely compromise control stability and dynamic response, potentially leading to system instability under extreme conditions. To address these challenges, this paper first investigates the current coupling mechanism considering the impact of control delay, unveiling the deeper mathematical structure and dynamic characteristics of the control system. A precise discrete domain high-speed motor model is reconstructed, and by introducing internal model control (IMC) theory, a system impedance gain modulation loop is designed. A digital current controller with enhanced decoupling capability has been developed, which extends the operational speed range of high-speed motors and improves control response under low CFR conditions. Finally, based on a high-speed prototype, dynamic speed variation experiments across a wide speed range of 0–60,000 r/min are conducted, validating the feasibility and superiority of the proposed approach.

This paper proposes an offline parameter estimation method of inverter-fed induction motors at standstill based on a two consecutive different voltages injection. The estimation method is achieved by recording the instantaneous stator current vector and instantaneous reference voltage vector at the same rotation angle. It possesses following characteristics. Firstly, the instantaneous rotating vector is used to estimate the motor parameters. It is no longer necessary to record the data of the entire cycle, thus reducing the computational and storage burden. Secondly, in order to eliminate the effect of inverter-error-induced deviation between the actual and reference voltage vectors, a method based on two consecutive different voltage injections is proposed. The proposed method replaces the actual voltage with the reference voltage for parameter estimation. Finally, a single-phase signal vector extension method is proposed, which expands the single-phase vector into a rotating vector by constructing an imaginary axis. Thus, the estimation method using the instantaneous rotating vector can also be performed in the single-phase experiment. Therefore, the implementation of the proposed method is easy, since it does not needto detect the actual voltage and store whole-cycle data, and the estimated parameters are accurate because the inverter error is considered. Simulation and experimental results verify the effectiveness of the proposed method.

The Hybrid Less Rare-Earth Synchronous Reluctance Motor (HLRE-SRM) has garnered widespread attention due to its economic advantages. This paper addresses the back EMF optimization for HLRE-SRM by constructing a simplified no-load magnetic circuit model to derive the relationship between the barrier angle and the motor's magnetic flux harmonics. Then, the Particle Swarm Optimization (PSO) algorithm, which does not rely on finite element analysis, is used to optimize the barrier position angle, reducing specific harmonic magnetic densities and enhancing the sinusoidality of the back EMF. Simulation results demonstrate that the proposed optimization scheme achieves a total harmonic distortion of less than 4%.

In this article, it is discovered that when the switching frequency increases, the current source rectifier (CSR) will suffer from a grid-side current distortion problem at the sector boundary. One of the reasons for this problem is the presence of narrow pulse at the sector boundary. To overcome this problem, a narrow pulse compensation solution is proposed. The solution attempts to alleviate the negative effects of narrow pulse from two aspects: 1) Avoiding the switch with an on -type narrow pulse in the drive signal to affect the turn- on/-off times of the corresponding bridge legs. 2) Improving the switching performance of the switch with an off -type narrow pulse in the drive signal by using a metal-oxide-semiconductor field-effect transistor with lower blocking voltage to make the actual switching characteristics closer to the ideal switching characteristics. An analysis of the generation mechanism of narrow pulse and its impact on the grid-side current is presented in this article. A 3 kW industrial prototype is also built to verify the effectiveness of the proposed solution. The test result shows that the proposed solution can effectively suppress the grid-side current distortion phenomenon, and improve the performance of CSR at high-switching frequency.

In the aerospace industry,the low-mass ultra-high-speed flywheel system play a critical role.In this paper,a kW-level Ultra-High Speed Permanent Magnet Synchronous Motor(UHSPMSM)as the core component of flywheel system is proposed and analyzed with considera-tion of multiple physical fields,including electromagnetic characteristics,mechanical strength and rotor dynamics.The integrated support structure is put forward to improve rotation accuracy and operation stability of the UHSPMSM.Further,influence of the integrated support structure on critical speed is explored,and the key parameters such as support position and support stiffness are designed.Moreover,the rotor strength is analyzed by analytical model developed of rotor stress that can deal with multiple boundary types.Material and thickness of the sleeve are optimized,and range of interference value is accurately limited based on four extreme operating conditions.The 3-D Finite Element Model(FEM)is used to validate the strength characteristics and stress distribu-tion of rotor.A 1.5 kW-150000 r/min UHSPMSM with integrated support system is manufactured and tested.The feasibility of UHSPMSM proposed and the accuracy of analysis method are verified through electromagnetic,temperature rise and vibration characteristics test.The machine prototype realizes the load operation at rated speed and the multi-physical-field characteristics achieve the design specification.

AbstractDifferent from the copper loss of general permanent magnet (PM) motors, the copper loss of ultra‐high‐speed permanent magnet motors (UHSPMSM) includes DC losses and eddy current losses, which lead to difficulty in analysis. In consideration of the influence of speed, wire diameter and current harmonic loss, DC copper loss and eddy current copper loss are calculated and analysed, respectively, so as to find the main excitation source of copper loss of UHSPMSM. Then, in order to calculate the Litz wire loss in a slotless stator, a Litz wire loss equivalent model is established, which can be used to accurately and quickly calculate the DC loss and eddy current loss of Litz wire independently. Finally, a copper loss separation method is designed to test copper loss of 550,000 rpm UHSPMSM considering the influence of the rotor PM flux at ultra‐high speed. The theoretical analysis and experimental results verify each other. In the end, the experimental results verify the effectiveness of theoretical analysis.

Loss characteristics and loss separation methods of ultrahigh-speed permanent magnet motors (UHSPMSM) are comprehensively studied in this article. In view of the influence of stator structure, material, winding type, control method, and fluid dynamics, the ac copper loss equivalent calculation model, fluid dynamic model, and finite element simulation model are established, respectively, to calculate and analyze the loss of each part of UHSPMSM. Moreover, a set of loss separation methods in dynamic is designed, which can separate stator core loss, dc copper loss, eddy copper loss, rotor eddy current loss, and mechanical friction loss of UHSPMSM one by one under the condition of considering the high-frequency electromagnetic field and fluid dynamic. A 550 000 r/min prototype and back-to-back loss separation setup is built to complete the experiment. Finally, loss distribution of the motor is obtained, which provides a certain reference for the loss research of an ultrahigh speed motor.

高速电机因其功率密度高、体积重量小、工作效率高等明显优势,受到越来越广泛的关注.高效稳定的驱动系统是充分发挥高速电机优异性能关键所在,该文主要从控制策略、转角估算以及功率拓扑设计等方面,分别分析高速电机驱动技术的难点,并总结归纳国内外当前研究成果,之后对高速电机驱动技术及其发展趋势进行总结展望.

基于超高速微型永磁电机(UHSMPMM)受多物理场特性制约的问题,该文对超高速微型永磁电机支撑系统、电磁(热)设计、结构强度及动力学等方面进行综合设计研究.首先,结合超高速微型永磁电机的工作特性及微型转子结构特点设计整体式支撑系统及电机整机架构;其次,研究高频条件下的电磁-损耗-温升特性,其中重点分析温升特性对转子结构强度的影响,并给出基于温度场耦合下的超高速转子结构强度关键参数的优化方法;再次,探究整体支撑系统中转子临界转速的影响因素及变化规律;最后,依据多耦合特性分析及优化结果,研制一台550000(r/min)/110W原理样机,并对样机进行实验测试.结果显示,该样机实现了稳定运行,从而证明了所提设计方法的有效性.

When permanent magnet synchronous motor is running at ultra-high speed, the tensile strength of permanent magnet is far lower than the compressive strength, and it is unbearable to withstand the large centrifugal tension caused by rotation. Generally, adding the non-magnetic alloy sleeve outside the permanent magnet is the protective measure. In this paper, the influences of static interference, the thickness of sleeve and sleeve material on rotor strength are analyzed, and the strength design rules of ultra-high speed permanent magnet synchronous rotor are summarized. Taking a permanent magnet synchronous motor with rated power of 1kW and rated speed of 500000r/min as an example, the strength design method is given and the rotor stress under three working conditions is checked by finite element method, which is static, rated speed and rotation at high temperature respectively, verifying the correctness of the design.