Compared to using uncontrolled rectifier, the use of active rectifier can significantly improve the output power of doubly salient electric generator (DSEG). The traditional six-state-angle-control (SSAC) strategy has limited effectiveness in improving the output power of DSEG. A mathematical model of DSEG in a rotating coordinate system oriented by back electromotive force (EMF) vector was established based on the principle of instantaneous reactive power. The reason why SSAC strategy is difficult to further improve the output power of DSEG was analyzed through this model. To address this issue, this paper proposed a back EMF oriented vector control (BEFOVC) strategy. Compared with SSAC strategy, BEFOVC can further optimize the output performance of DSEG, reduce copper loss, phase current peak and THD, and suppress the torque ripple of DSEG. Finally, the feasibility and effectiveness of the proposed method were verified through simulations and experiments on a 12/8-pole DSEG.

Aiming at the problem of speed waveform overtwisting in the sensorless control system of permanent magnet synchronous motor, this paper combined the STA sliding mode controller and PI controller organically based on the Super-Twisting Algorithm (STA). A Fast Super-Twisting Sliding Mode Controller (FST-SMC) was designed, and it was verified by simulation that its resistance to load disturbance was strong and the speed waveform almost had no overmodulation. Secondly, in view of the problems of large buffering and low observation accuracy of the traditional Sliding Mode Observer (SMO), this paper introduces the super-spiral sliding mode control rate into the observer and designs a super-spiral sliding mode observer. Simulation results show that the observer designed in this paper can accurately observe the rotor position and speed. Effectively reduce buffeting, with good anti-interference ability and robustness.

In this paper, a method of parameter identification of Permanent Magnetic Synchronous Machine (PMSM) based on improved Beetle Swarm Optimization Algorithm (BSO) is proposed. The idea is to combine Beetle Antennae Search Algorithm (BAS) and Particle Swarm Optimization (PSO). The algorithm adopts adaptive weights and adaptive learning factors to optimize parameters, and adopts variable step search strategy and nonlinear inertia factor to form an improved BSO optimization algorithm. The simulation results show that the improved BSO algorithm can identify PMSM parameters faster, has faster convergence speed, higher identification accuracy, good dynamic performance and small identification error.

Hybrid excitation doubly salient motor (HEDSM) is suitable for aviation starter/generator because of the advantages of high-power density, high reliability and flexible control. However, the salient pole and slot structure can cause high torque ripple and serious nonlinear magnetic field distribution. In this paper, we present a multi-objective optimization design approach for the HEDSM. In order to increase the output torque of the motor and reduce the torque ripple of the motor, the Taguchi method is used to optimize parameters of the motor. The ANOVA is often used in traditional Taguchi method to analyze the data of orthogonal experiments to determine the final optimization result, but it is more suitable for single-objective optimization. Therefore, the grey relational analysis (GRA) is used instead of ANOVA to improve the Taguchi method, so as to complete the multi-objective optimization design of the motor. Finally, the simulation and analysis of characteristics for the HEDSM verifies the effectiveness of the optimization method, which enriches the rapid design and optimization methods of this kind of doubly-salient motors.

对航空宽变频交流信号的异步采样方法展开研究,首先分析宽变频基波有效值的理论误差,根据有效值理论误差提出了优化的宽变频有效值计算公式,消除了计算方法带来的理论误差;同时,推导了在基波采样频率下谐波有效值理论误差,在优化的计算公式下谐波有效值计算误差为0.最后,在发电机控制器硬件平台上对宽变频范围内异步采样方法的推导进行验证.实验结果验证了误差理论推导及优化计算公式的正确性;在航空宽变频范围内,采用优化有效值计算公式的异步采样方法具有可行性和高采样精度.

During the closed formation control of multiple unmanned aerial vehicle UAV's strategy, the flight direction of UAV's will be disturbed, which is difficult to predict accurately, due to the wind disturbance, atmospheric pressure and aerodynamic force produced by the UAV's. In this research, decentralized closed formation heading flight controllers is proposed for the correction of heading angle of UAV's based on consensus theory. Collisions may occur in the course of the heading angle correction, the convergence of heading angle correction system is calculated by eigenvalue. The robustness of the proposed heading flight controller is simulated on different communication structure, and it proves that it has better robustness and fast convergence.

The impedance-based stability criterion is usually used to evaluate the performance of a current-controlled inverter in the weak grid with considerable grid impedance at the point of common coupling (PCC). The stability of the real inverter-grid system is the same as the virtual system where the ratio of the grid impedance and the inverter output impedance is the open-loop transfer function. However, not only the stability but also the rejection of the grid current harmonics is critical to the real inverter-grid system. So far, existing studies have not revealed the relation between the stability margin of the virtual system and the grid current harmonics rejection of the real system. Therefore, this study focuses on the control and design based on impedance-based stability criterion for improving not only the stability but also the grid current harmonics rejection. The design guideline of the phase margin of the virtual system is derived through mathematical derivations. A case study based on an LCL-filtered inverter has been provided to verify the analysis. Then, an improved control for the LCL-filtered inverter has been proposed. Selected waveforms have been provided to verify the improved control and design.

电磁干扰(electro magnetic interference,EMI)滤波器是一种抑制电力电子系统中传导电磁干扰的重要手段,其中集成式EMI滤波器由于体积小、高频性能好等优点得到广泛关注。该文介绍了一种新型集成式母线型EMI滤波器,这种滤波器将传输线与滤波器相结合,通过金属导体的"集肤"与"邻近"效应对低频工作电流与高频噪声电流进行分离,并对噪声电流实现"反射"与"耗散"双重衰减。论文采用有限元法,综合考虑了母线型EMI滤波器"磁-热-流体"多物理耦合场特性,从材料选择、电气及结构参数设计、滤波性能分析、温升特性分析等方面对滤波器进行了系统性的设计,对滤波器镀层结构及厚度、滤波器最大工作电流密度等具有工程应用价值的参数进行了详细计算,并给出了参考数值。母线型EMI滤波器滤波测试效果及温升实验表明滤波器具有较好的滤波性能和较强的载流能力,具有进一步开发并实际应用的前景。

针对目前被动式孤岛检测方法的检测盲区大、可能发生伪孤岛的误判,以及主动式孤岛检测会引入谐波、影响电能质量的问题,提出了一种基于FFT与小波变换的新型孤岛检测方法。通过对公共点(PCC)的电压信号进行FFT分析,得到75 Hz非整数次谐波含量,以及对PCC处电压信号进行小波多分辨率分析,提取出电压信号高频分量,以这两种特征量作为识别孤岛状态的指标,通过MATLAB/Simulink仿真与实验验证,结果表明提出的方法具有可行性,能够有效识别出孤岛、无检测盲区。

To satisfy the requirement for high voltage and high power applications, a multi-phase multi-level LLC resonant converter with modular structure was proposed in this paper. The voltage stress on the primary switch is only one-nth of the input voltage due to its multi-level structure, the current rating of power devices can be reduced by introducing the proposed multi-phase structure. Using the variable frequency control strategy, the primary switches can operate with zero-voltage-switching (ZVS) and the rectifier diodes can operate with zero-current-switching (ZCS) in a wide input voltage and load range. Take the topology with three modules for example, the operation principle of the converter under variable frequency control method was analyzed, the equivalent model and voltage gain of the converter were derived according to fundamental harmonic analysis. The parameters were designed under the condition that the switching frequency is higher or lower than the resonant frequency. To validate the feasibility of the proposed converter, a prototype with 540V~660V input and 400V/5A output has been built and tested in the lab and the experimental results can be agree with the theoretical analysis.

A diode-clamped three-level dual-boost reversible PWM rectifier is proposed in this paper. As this topology is deduced from the dual-boost PWM rectifier, it inherits the merits of no hidden danger of shoot-through and no body diodes' reverse recovery problems, which are the two main problems of the conventional half-bridge and full-bridge rectifiers. Thus, the proposed circuit has the advantages of high reliability and improved efficiency. In addition, compared with the dual-boost PWM rectifier, the voltage stresses of power switches reduce to half the output voltage, which helps to expand the usage of the proposed circuit to higher-voltage occasions. The hysteresis current controller is involved in the circuit control system to eliminate the loop-current. The operational principle, switching logics and design details of the important components are all deeply analyzed. Theoretic analysis is supported by the experimental results performed by a 1kW engineering prototype.

In this paper, a novel flux-switching electromagnetic (FSEM) machine is proposed, which can not only maintain the advantages of doubly-salient electromagnetic (DSEM) machine,such as simple rotor structure and excitation adjustable,but also realize bipolar flux-linkage change by setting field windings into the slots of stator teeth. The special topology, operation principle, design dimensions were introduced and predicted by a 3-phase 6/5-pole FSEM machine. The finite-element analysis results verify that the proposed machine has bipolar flux and good sinusoidal back-electromotive force (EMF), thus it is suitable for brushless AC (BLAC) operation. Moreover, the torque (power) density of the proposed machine is higher than that of a DSEM machine, under the same electrical conditions,.

The structure of the motor and the pattern of windings have great influence on the electrical excitation flux-switching (EEFS) motor. This paper developed a 200KW EEFS machine in the light of drive motors of the high power air conditioning compressor, and introduced the operate principle and basic parameters of the motor. The EEFS machine was optimized through FEM analysis and simulated with Maxwell 2D in a comprehensive consideration of performance indexes such as rated voltage and power. By changing basic sizes of the motor, electromagnetic performances, loss and efficiency of different structures of EEFS machine were compared to get the most suitable structure, and a proposal of radial distribution was given. The performance included the phase flux-linkage, back electromotive force (EMF) waveforms, no load characteristics and load characteristics, etc. The results provided theoretical basis of the development of high reliability of the doubly salient motor.

In order to calculate the iron losses in motor accurately,the magnetic field model of the motor based on the 2D FEM were established.The extraction of the density of core flux with rotational state based on coupling boundary was proposed and the traditional calculation model of iron losses was modified and improved.Then a 30/20 doubly salient electro-magnetic motor were analyzed based on this magnetic field.With the measured iron losses of the motor applied with different exciting currents,the coefficients of the iron losses model were calculated.Finally the theoretical iron losses were compared with the measured value under different speed and the accuracy of the model was verified.

The one-cycle-controlled (OCC) three-phase power-factor-correction (PFC) is a promising rectification method that eliminates harmonics and improves the power factor. It features great simplicity, high performance, and excellent stability. In the conventional OCC control strategy, the PWM signals are generated by the sampling input inductor currents and carrier waveform whose amplitude is generated by voltage regulator. So, the generation of PWM signals can be regarded by SPWM (Sinusoidal Pulse Width Modulation) modulation. Under this control strategy, the output voltage of three-phase PFC rectifier is quite high, which is not benefit for reducing the switches voltage level and improving the efficiency of rectifier. Based on the analyses of OCC three-phase four-leg rectifier that used in 3P4W (three-phase four-wire) system, the SAPWM (Saddle Pulse Width Modulation) modulation that can be obtained by injecting three times harmonic into SPWM modulation is proposed to introduce in the conventional OCC control strategy. The rectifier's output voltage could be reduced by the modified OCC control strategy and the efficiency of converter could be also improved. The modified OCC control strategy can be also applied in the three-phase three-leg rectifier and three-phase three switches Vienna rectifier that used in the 3P3W(three-phase three-wire)system. The validity of the theoretical analysis and feasibility of the modified OCC control strategy are verified by system simulation and experimental results based on a 4.5-kW three-phase four-leg rectifier prototype.

Based on transient FEM（finite element method） to simulate and analysis the relationships of output power of the Multi-cell three-phase wound-field doubly salient DC generator when composing elements increases which simulation results are basically identical to the deducing conclusion.Then the variation between Maximum output power and stator/rotor poles with the same armature diameter is further studied,such that an optimal stator/rotor pole design can be reached.

The Doubly Salient Machine(DSM) is a new type variable reluctance machine. This paper briefly introduces this machine's structure features,classes and uses first,and analyses and introduces the principle,system construction,features of the Doubly-fed Asynchronous wind power system and Permanent Magnet Direct-driven wind power system, at the basis of which the Direct-driven and Indirect-driven Doubly Salient wind power systems are proposed,such that the system complexity and cost is highly reduced,and the machine is quite structural simple,rigid,fabricated more easily,and of satisfactory working reliability and maintenance.So the Doubly Salient wind power system may have a brilliant future.

The field windings and permanent magnets of compound flux-path three-phase stator hybrid excited doubly salient DC generator are on the same cross-section orthogonal to the shaft,where flux excited by field windings and permanent magnets multiplexes the core paths.This machine has small excitation power,can regulate its field in a designing range,and outputs in one channel or double channels.This paper introduces the typical topologies,analyses the operating modes with Transient FEM,and extracts the inductance based on the field analysis,then calculates nonload and external V-I characteristics comparatively,at last open-loop cross-regulation-rate of double channel outputs is also simulated.The results point out that this machine has a wide application future,which can be used as brushless DC generators in isolate generating systems and connects to the grid;it is especially suitable for high-speed generators applied in aeronautics or other field works and can realize the integrated start /power generation.

Using transient finite element method to analyze this Brushless DC generator's static parameters and operation performance in order that the performance under real load can be solved directly including nonlinear saturation of core materials,fringing magnetic field,armature reaction of lumped windings.Emphasis introduces the structure and topology features of wound-field doubly salient DC generator,then the mathematic model of this generator is built up,which lies in extraction of static parameters such as winding inductance,coupled inductance.Also,a 72/48 multi-cell three-phase wound field doubly salient DC generator is simulated to analyze the operating characteristics of different load generators,and provided a beneficial reference for the machine designer.

Starter/Generator integration is a major trend of modern aero power supply systems.The QF18D Aero Starter/Generator(ASG) adopts the three-phase Doubly Salient Machine(DSM),which boasts of the no-permanent-magnet no-winding rotor,strong construction,convenient fabrication,fine inverting operation,etc,such that it is very suitable for high speed high altitude aviation.This paper first makes a brief introduction to the structure and working principle of the QF18D ASG;then based on a mixed methodology of FEM simulation and lab test studies the QF18D Doubly Salient DC Generator(DSDCG)'s characteristics including nonload,short-circuit,external and regulation in detail,mainly focusing on the mechanism of the influence of commutation overlapping and armature reaction to the machine's key characteristics;finally,lab testing of cold running and hot start of the aerial turbine engine is implemented and superior starting performance of the QF18D system is verified.