Micromotors

Magnetic field modulated permanent magnet linear generator improves the design point speed and electromotive force of the motor by utilizing the magnetic modulation effect,thereby improving the power density of the motor,especially suit-able for wave energy generation.Based on the design input,a dual-mover magnetic field modulated permanent magnet linear genera-tor design scheme was completed,and the air gap magnetic field,static characteristics,open-circuit performance,and load characteristics of the motor were analyzed and calculated using finite element method.The computational results demonstrate the rationality and correctness of the design.In order to reduce the thrust fluctuation,the speed ratio,relative width of the modulation unit,and thickness of the modulation unit were optimized,providing reference for the design of dual-mover perma-nent magnet linear generator.

Using a permanent magnet DC motor as the test object,under the same test conditions,the motor efficiency was tested twice using a power analyzer and a dynamometer with different ranges and accuracies.Analyzed the sources of uncertainty in motor efficiency measurement,described in detail the evaluation process of each uncertainty component,calculated and synthesized the standard uncertainty of motor efficien-cy.Analyzing the evaluation process and results of measurement uncertainty provides a certain reference for selecting instrument equipment when measuring motor efficiency or conducting other inspections.

Aiming at the technical requirements of a high power density servo drive motor for a rotor UAV,through analysis and finite element simulation optimization,it is concluded that the surface-mounted perma-nent magnet rotor structure of the inner rotor is relatively more suitable for balancing power density,efficien-cy,torque ripple and other indicators.Based on this,a servo drive motor with high power density,high effi-ciency and low torque ripple was designed,and the prototype was tested and verified,and its performance index was satisfied with technical requirements.

In response to the shortcomings of traditional magnetic circuit design for resolver,a high-precision modern design method for resolver was studied.Maxwell software was used for finite element simulation of re-solver magnetic circuit,and combined with Matlab software,extreme value sampling and cubic spline inter-polation were used to accurately extract the envelope of output signal,so as to effectively evaluate the sine of output signal;Using multi-angle electromagnetic simulation analysis method and the"forward and reverse tangent method"of the output signal of the resolver,combined with Matlab software,to achieve the calcula-tion of the electrical accuracy of the resolver at all angles,and effectively evaluate the electrical accuracy values of the resolver rotor at different positions.The experimental results were compared with the actual test results of resolver under 8 different base numbers and excitation conditions,proving its effectiveness.

Electrolytic capacitor-less three phase permanent magnet synchronous motor drive system has the advantage of long lifetime,high power density and so on.This paper made a detailed analysis of the basic structure and working principle of the system.The relationship of q axis current and the output power of the inverter was analyzed and q axis current control strategy was given.The simple and valid control strategy of d axis current was given based on DC bus voltage limitation.In order to improve the power factor of the grid side,a notch filter was added to filter the specified harmonic component in the given d-axis voltage.The simulation results show that the control strategy can effectively reduce the input current distortion rate.

A permanent magnet brake(PMB)was presented for the reliability and safety of the dual-redun-dancy differential actuation system,and the composition and working principles of the permanent magnet brake were introduced.Based on the equivalent magnetic circuit method,the mathematical models for loc-king and unlocking condition of the brake were established.The results derived from the mathematical model agreed well with the FEM model results.According to the analysis of magnetic performance and frictional characteristic,a friction pair was designed.Finally,experiment was carried out in the prototype,and the simulations agreed well with the measured results.

In order to address the problem of inaccurate identification of electric motor parameters resulting from the calculation of incorrect magnitude and phase of motor voltage and current during the identification process of the asynchronous propulsion motor,a gradient descent-based asynchronous motor parameter identi-fication algorithm was proposed.By passing different voltages into the stator resistance,relevant motor sam-pling data that can be used to identify the stator resistance,rotor resistance,and mutual inductance of the motor are obtained.The theoretical voltage of the inverter was modified by a third-order curve fitting method,ultimately increasing the accuracy of the rotor resistance identification.By numerically fitting the waveforms of motor AC voltage and current using the gradient descent method,accurate waveform magnitude and phase were estimated,and the power factor was calculated,allowing the precise identification of motor rotor resist-ance,leakage inductance,and mutual inductance.An identification experiment was conducted on a 7.5 kW motor using a self-developed inverter based on TMS320F28379D,which demonstrated the effectiveness of the proposed algorithm in improving identification accuracy.

Aiming at the phenomenon that the back EMF waveform of brushless DC motor is seriously distort-ed when the motor is controlled by back EMF to run at low speed without position sensors,a brushless DC motor back EMF position sensorless control strategy based on median filter was proposed.Firstly,based on the motor voltage equation,the suspended phase voltage equation under the PWM modulation mode of H_PWM-L_ON was obtained,and the accurate zero crossing point of the back EMF was also obtained.Second-ly,Simulink was used to carry out simulation experiments to compare the effects achieved by the method of using the median filter with the effects achieved by the method of ordinary back EMF method,which reflec-ted the superiority of the proposed method.And this paper gave a design basis for the window size of the me-dian filter.Finally,simulation was carried out by the PWM_ON modulation method,which was used to prove that the proposed method was not affected by the PWM modulation method.And the commutation torque ripple was further suppressed by the Lag ahead of commutation.Then good results were obtained.A series of simulation experiments have proved that the position sensorless control method proposed in this pa-per has good commutation accuracy and high reliability when brushless DC motor is running at low speed.

Aiming at the precise force control of electro-mechanical brake system of rail transit,the high dy-namic and reliable control method was studied in this paper.Based on the structural characteristics and mathematical model of the brake system,a four-closed-loop brake force control strategy was proposed.First-ly,the closed-loop control strategy of the brake force was established based on the force control theory.The proposed four-loop braking force control includes force closed-loop,position closed-loop,velocity closed-loop and current closed-loop.The four-closed loop control method was compared with the traditional two-closed loop force control method by using the analysis method of classical control theory.Then,the two control methods were compared based on linear simulation model and co-simulation respectively.The linear simulation and co-simulation show that the control method of four-closed loop brake force control improves the rapidity and stability of the braking force response of the system,that is,the proposed method increases the safety and reli-ability of rail transit.The control method proposed in this paper has been verified by experiments.

Controlling the energy storage converter can avoid the problems of overcharge and overdischarge of the energy storage unit of the DC microgrid.In order to improve the stability of the DC microgrid in opera-tion,a double-layer fuzzy control method for the energy storage converter of the DC microgrid with constant power load was proposed.By constructing the average switching model of energy storage converter,the e-quivalent circuit diagram with constant power load in DC microgrid was obtained,and the differential equa-tion of the equivalent circuit was constructed.When the differential state equation gradually converges to the equilibrium point,the running state of DC microgrid was judged,and the influence of energy storage convert-er with constant power load on DC microgrid was analyzed.The first-layer fuzzy controller was used to adjust the SOC of the energy storage converter in the DC microgrid,and the second-layer fuzzy controller was used to solve the problem that the real load deviates from the load scheduling curve in the power correction process of the first-layer fuzzy controller.Through the double-layer fuzzy control,the power command of the energy storage converter was obtained,and the double-layer fuzzy control of the energy storage converter was real-ized.The experimental results show that the proposed method can prevent the sudden change between the output power of photovoltaic cells and the power consumed by the load,thus avoiding the battery's initial SOC value being low and withdrawing from power supply in advance,and improving the stability of DC mi-crogrid operation.

This article is based on the relevant requirements of GB standards and ISO26262 functional safety standards.A safety analysis mainly from the perspective of software functionality and hardware was conducted for the sudden loss of assist of the electric power steering system,and introduced the safety path for the steer-ing system to avoid sudden loss of assist.Which having a new understanding of this safety goal at the safety concept level for readers,and also provide guidance and reference on how to achieve the safety goal of avoi-ding sudden loss of assistance from the system level.

The traditional PWM rectification technology for permanent magnet synchronous generators usually uses optical encoders to obtain accurate position and angle information.However,the installation of optical encoders will increase system costs,and their performance is susceptible to changes in the external environ-ment,resulting in reduced reliability of the system.Combing the analysis on basic control methods for power generation systems,the sensorless control strategy based on sliding mode observer method was proposed.The back electromotive force can be estimated by the sliding mode observer from voltage and current values of each PWM cycle.And the rotor position was determined by the phase locked loop.Both simulation and ex-perimental results demonstrate that the proposed method can accurately and effectively estimate the rotor po-sition angle and output a voltage waveform that meets the standard.

A composite PI controller is designed to reduce the overshoot of speed response in response to the frequent variable speed and load disturbance operating conditions of permanent magnet synchronous motors(PMSM)used in electric engineering machinery.At the same time,in order to reduce the influence of sys-tem variable load disturbance,a load torque sliding film observer was proposed,whose torque observation value was compensated to the given current loop to achieve rapid response to the servo load and improve the system's anti load disturbance performance.Through simulation and experiments,it has been proven that the designed speed composite PI controller can reliably reduce speed response overshoot and improve the sys-tem's anti load disturbance performance;The proposed load torque observer and feedforward compensation control algorithm can accurately observe the real-time load disturbance,compensate to the load disturbance given by the current loop,effectively reduce the speed fluctuation,and improve the dynamic performance.

Based on the improved particle swarm optimization algorithm,through the establishment of the mathematical model of the split winding permanent magnet synchronous motor,the inter-turn short-circuit fault was diagnosed,and the optimization objective of the system was obtained.The preliminary diagnosis method of three-phase unbalance and the optimization algorithm based on improved particle swarm optimiza-tion were verified by using Matlab/Simulink platform.The simulation results verify the correctness of the a-nalysis method and mathematical model,and obtain the basic information of the permanent magnet synchro-nous motor interturn short circuit fault model,so as to accurately obtain the fault location,the specific objec-tive of system optimization and fault tolerance information.The theoretical basis has strong applicability,and can be used in electric vehicles including open winding permanent magnet synchronous motor,aerospace and many other fields.

根据某型制导炮弹高过载、高响应以及小型化的需求,本文设计了一款以直流无刷电机为控制对象,控制策略为电流、位置、速度三闭环反馈控制系统的双通道电动舵机.确定电机定制要求并对减速机构进行设计,再通过机械结构优化设计,提高设备的抗高过载性能.舵机以GD32F407 为主控制器,驱动电路采用Ir2136S三相桥驱动芯片与MOS管组成的全桥电路.试验结果表明,设备具有良好的转速跟随性能,角速度大于240°/s,调节时间小于70 ms,频带宽度可达18 Hz,加载超调量为0.25%,稳态误差≤0.25°,满足设计要求.

基于永磁同步电机d、q坐标系电流模型,运用自适应方法和稳定性理论,在模型参数未知的情况下,设计一种参数自适应电压矢量控制律,该控制律利用d、q轴电流误差、模型的估计参数等信息,通过引入误差反馈补偿、参数估计补偿等方式消除d、q电流的控制误差,并通过参数自适应律消除模型存在未知参数带来的影响,特别是有效处理控制输入存在乘积因子未知的情况,较传统的PID控制方法提高了环路控制的性能,通过仿真验证了该控制律的有效性.

本文主要阐述了逆变器的方案选择及其控制实现,详细阐述了高频升压逆变器方案选择与构成的理论依据.在此基础上,对高频升压逆变器的电路与控制进行了设计,给出了逆变器控制流程.

电机是一种不均质体,由多种不同温度特性和膨胀系数的金属和非金属材料组成,因此环境温度骤变会引发电机故障甚至失效.为了探究环境温度变化对永磁式有刷直流力矩电动机工作性能的影响,本文以一台有刷直流力矩电动机为例,基于不同温变速率的温度循环筛选试验验证,建立试验现象分析与试验数据对比,明确了环境温度变化对有刷直流力矩电动机性能指标或系统可靠运行的影响,为军用武器装备系统研制阶段的方案设计提供了一定的工程实践价值和理论依据.

基于超声电机电气绝缘特性设计,识别出影响电机绝缘特性的主要因素为摩擦材料,分析摩擦材料的导电机理,在此基础上提出控制策略,并制备摩擦材料,装配电机验证了控制策略的有效性,为工程应用提供借鉴.

针对增程式汽车发电机运行过程中噪声过大的问题,通过电磁力波特征阶次分析和振动噪声定位分析,并提出了相应的优化方案.首先,通过电磁力波特征阶次分析,探讨了电枢反应和永磁体对电磁力波的影响.其次,通过噪声定位分析,确定了额定工况下噪声的主要成因,并针对该问题提出了改进电机内部转子结构添加转子辅助槽的方案,优化了电机气隙磁密.最后对电机建模进行有限元振动噪声的仿真分析,评估了优化方案的效果,改进后电机噪声显著降低.