无刷双馈电机运行特性的等效磁网络分析法

无刷双馈电机(BDFM)结构特殊,磁场调制机理复杂,目前尚缺少有效工具可快速而准确地对其运行特性进行分析。为此,根据磁网络的基本概念,结合笼型转子BDFM的结构特点并考虑铁心饱和与转子旋转的影响,阐述了笼型转子BDFM等效磁网络的建模方法;在此基础上,建立了一个笼型转子BDFM样机的动态磁网络模型,利用回路法对其进行求解,进而得到并分析了BD-FM在多种不同工况下的运行特性;最后,将动态磁网络模型的分析结果与有限元分析结果和样机实验数据进行了对比。结果表明,笼型转子BDFM动态磁网络模型在保证准确性的前提下,计算速度与有限元法相比明显提升,为分析笼型转子BDFM的运行特性提供了新思路。

Finite-Control-Set Model Predictive Control of Permanent Magnet Synchronous Motor Drive Systems——An Overview

Permanent magnet synchronous motors(PMSMs)have been widely employed in the industry. Finite-control-set model predictive control(FCS-MPC), as an advanced control scheme, has been developed and applied to improve the performance and efficiency of the holistic PMSM drive systems. Based on the three elements of model predictive control, this paper provides an overview of the superiority of the FCS-MPC control scheme and its shortcomings in current applications. The problems of parameter mismatch, computational burden, and unfixed switching frequency are summarized. Moreover, other performance improvement schemes, such as the multi-vector application strategy, delay compensation scheme, and weight factor adjustment, are reviewed. Finally, future trends in this field is discussed, and several promising research topics are highlighted.

Two-vector Dimensionless Model Predictive Control of PMSM Drives Based on Fuzzy Decision Making

Model predictive controls(MPCs) with the merits of non-linear multi-variable control can achieve better performance than other commonly used control methods for permanent magnet synchronous motor(PMSM) drives.However,the conventional MPCs have various issues,including unsatisfactory steady-state performance,variable switching frequency,and difficult selection of appropriate weighting factors.This paper proposes two different improved MPC methods to deal with these issues.One method is the two-vector dimensionless model predictive torque control(MPTC).Two cost functions(torque and flux) and fuzzy decision-making are used to eliminate the weighting factor and select the first optimum vector.The torque cost function selects a second vector whose duty cycle is determined based on the torque error.The other method is the two-vector dimensionless model predictive current control(MPCC).The first vector is selected the same as in the conventional MPC method.Two separate current cost functions and fuzzy decision-making are used to select the second vector whose duty cycle is determined based on the current error.Both proposed methods utilize the space vector PWM modulator to regulate the switching frequency.Numerical simulation results show that the proposed methods have better steady-state and transient performances than the conventional MPCs and other existing improved MPCs.

Electromagnetic Performance Analysis of Flux-Switching Permanent Magnet Tubular Machine with Hybrid Cores

The performance of traditional flux switching permanent magnet tubular machine(FSPMTM)are improved by using new material and structure in this paper.The existing silicon steel sheet making for all mover cores or part of stator cores are replaced by soft magnetic composite(SMC)cores,and the lamination direction of the silicon steel sheet in stator cores have be changed.The eddy current loss of the machine with hybrid cores will be reduced greatly as the magnetic flux will not pass through the silicon steel sheet vertically.In order to reduce the influence of end effect,the unequal stator width design method is proposed.With the new design,the symmetry of the permanent magnet flux linkage has been improved greatly and the cogging force caused by the end effect has been reduced.Both 2-D and 3-D finite element methods(FEM)are applied for the quantitative analysis.

Development of a New Flux Switching Transverse Flux Machine with the Ability of Linear Motion

This paper proposes a new rotary flux switching transverse flux machine with the ability of linear motion(FSTFMaLM),in which both the stator and the rotor cores are made by using soft magnetic composite(SMC)materials.With the special design pattern,for the rotary motion model,the proposed machine can combine both the advantages of the flux switching permanent magnet machine(FSPMM)and the transverse flux machine(TFM).It can output with relatively high torque density,and as there is no windings or the magnets on the rotor cores,the proposed machine can operate in the high speed region to improve the output power.With the adoption of the SMC materials,the manufacturing of this machine can be quite easy.By stacking the rotor core together and prolong it with the determined length in the axial direction,in addition with the special control algorithm,the proposed machine can have the ability of the linear motion.In this paper,the operation principle of this machine has been explained and the design methods are also presented.To seek the better performance,the main dimension of the machine is optimized,and for the performance evaluation,the finite element method(FEM)is adopted.The proposed machine can be used for the electric driving systems,robotic systems or other applications where the linear motion ability is required.

Robust Multiobjective and Multidisciplinary Design Optimization of Electrical Drive Systems

Design and optimization of electrical drive systems often involve simultaneous consideration of multiple objectives that usually contradict to each other and multiple disciplines that normally coupled to each other.This paper aims to present efficient system-level multiobjective optimization methods for the multidisciplinary design optimization of electrical drive systems.From the perspective of quality control,deterministic and robust approaches will be investigated for the development of the optimization models for the proposed methods.Meanwhile,two approximation methods,Kriging model and Taylor expansion are employed to decrease the computation/simulation cost.To illustrate the advantages of the proposed methods,a drive system with a permanent magnet synchronous motor driven by a field oriented control system is investigated.Deterministic and robust Pareto optimal solutions are presented and compared in terms of several steady-state and dynamic performances(like average torque and speed overshoot)of the drive system.The robust multiobjective optimization method can produce optimal Pareto solutions with high manufacturing quality for the drive system.

Practical Tracking Method based on Best Buddies Similarity

Visual tracking is a crucial skill for bionic robots to perceive the environment and control their movement.However,visual tracking is challenging when the target undergoes nonrigid deformation because of the perspective change from the camera mounted on the robot.In this paper,a real-time and scale-adaptive visual tracking method based on best buddies similarity(BBS)is presented,which is a state-of-the-art template matching method that can handle nonrigid deformation.The proposed method improves the original BBS in 4 aspects:(a)The caching scheme is optimized to reduce the computational overhead,(b)the effect of cluttered backgrounds on BBS is theoretically analyzed and a patch-based texture is introduced to enhance the robustness and accuracy,(c)the batch gradient descent algorithm is used to further speed up the method,and(d)a resample strategy is applied to enable the BBS to track the target in scale space.The proposed method on challenging real-world datasets is evaluated and its promising performance is demonstrated.

Suggestion for aircraft flying qualities requirements of a short-range air combat mission

Owing to the lack of a direct link with the operations in short-range air combat,conventional aircraft flying qualities criteria are inappropriate to guide the design of a task-tailored flight control law.By applying the mission-oriented flying qualities evaluation approach,various aircraft with different control law parameters are evaluated on a ground-based simulator.This paper compares the evaluation results with several conventional flying qualities criteria,and discusses the appropriate parameter combination to reflect the flying qualities requirements of short-range air combat.The comparison and analysis show that a short-range air combat mission requires a higher minimum short period mode natural frequency and a smaller maximum roll mode time constant,and allows a lower minimum pitch attitude bandwidth and a higher maximum short period mode damp ratio than those of conventional flying qualities criteria.Furthermore,a combination of the pitch attitude bandwidth,the pitch attitude magnitude at the bandwidth frequency,and the pitch attitude transfer function gain can define the flying qualities requirements of short-range air combat.The new metric can successfully predict the flying quality levels of aircraft in a short-range air combat mission.

Modified PI Controller with Improved Steady-State Performance and Comparison with PR Controller on Direct Matrix Converters

This paper proposes a modified proportional-integral(PI)controller and compares it with a proportional-resonant(PR)controller.These controllers are tested on a three-phase direct matrix converter(MC).The modified PI controller involves current feedforward together with space vector modulation(SVM)to control the MC output currents.This controller provides extra control flexibility in terms of the current error reduction,and it gives improved steady-state tracking performance.When the coefficient of current feedforward is equal to the load resistor(K=R),the steady-state error is effectively minimized even when regulating sinusoidal variables.The total harmonic distortion is also reduced.In order to comparatively evaluate the modified PI controller,a PR controller is designed and tested.Both the modified PI and PR controllers are implemented in the natural frame(abc)in a straightforward manner.This removes the coordinate transformations that are required in the stationary(αβ)and synchronous(dq)reference frame based control strategies.In addition,both controllers can handle the unbalanced conditions.The experimental and simulation results verify the feasibility and effectiveness of the proposed controllers.