基于三电平功率变换器提高SRG输出功率

分析了开关磁阻发电机(SRG)的发电运行条件和提高输出功率的关键因素,提出用三电平功率变换器加入一个中间惯性状态,增大励磁电流和发电续流区的平均电流,以提高SRG的输出功率;采用SRG电压反馈控制系统,保证同时获得良好的恒定输出电压品质;提出三电平功率变换器的开关控制策略,建立基于自励发电模式和电流斩波控制模式的SRG电压反馈控制系统仿真模型;仿真研究验证了该方法的可行性和有效性.     

开关磁阻发电机他励模式下的简易功率变换器控制

针对不对称半桥功率变换器的主开关器件较多的缺点,提出开关磁阻发电机(SRG)他励模式下的简易功率变换器控制。给出并分析简易功率变换器的主电路结构,建立相应的SRG他励发电数学模型,分析能量转换和发电效率,与不对称半桥功率变换器相比,其每相只需一个主开关器件,降低了成本,能在SRG停转时对负载供电,且在一定条件下能提高发电效率。对基于简易功率变换器的SRG他励发电系统进行了仿真和实验,仿真和实验结果表明系统能够稳定运行,发电质量好,验证了该方法的可行性和简单性,具有一定工程应用价值。     

高增益耦合电感双倍压单元组合Cuk-Boost变换器

为解决传统Cuk变换器升压能力不足、应力较大等问题,将Cuk变换器与Boost变换器进行叠加组合,并引入耦合电感双倍压单元,提出一种应用于高增益场合的组合式Cuk-Boost变换器。该变换器增加了以改变耦合电感匝比来调节电压增益的方式,并将拓扑中电容-二极管支路在作为倍压电路的同时还可作为钳位电路来吸收漏感能量,在使用较少元器件的情况下提高了变换器功率密度,降低了电压应力。对变换器工作原理和性能进行分析,给出各项设计参数,对比不同变换器的电气性能,最后通过搭建原型电路验证理论分析的正确性。     

基于MPC的耦合电感飞跨电容双向DC/DC变换器功率均衡解耦控制策略

耦合电感功率变换器因耦合电感阻抗、电感值等参数差异易导致功率不均衡。针对耦合电感飞跨电容双向DC/DC变换器,提出一种基于模型预测控制（MPC）的功率均衡解耦控制策略。通过对变换器原理进行分析,建立基于电感电流解耦的数学模型,得到包括电感电流和飞跨电容电压等6个控制变量的解耦控制方法。在此基础上,提出基于MPC的功率均衡解耦控制策略。同时,为降低MPC算法的运算负荷,根据解耦控制模型重构模型预测价值函数,实现各控制变量独立动态寻优,使系统能在稳定控制输出电压及飞跨电容电压的同时,实现两相耦合电感的功率均衡控制。最后,通过理论分析及实验对所提策略进行有效验证。     

基于功率平衡算法的NPC三电平变换器 中点电压控制

分析了中点钳位型三电平变换器的中点电压数学模型,推导出三相功率与零序电压的传递函数。提出一种新型的注入零序电压控制方案,该方案通过控制中点处的零序总功率为0,来实现中点电压的平衡控制。具体方案是,通过计算中点处的三相功率偏差,经PI调节器输出零序电压调制波,经过3 s/2 r坐标变换,叠加至三相基波调制波,并采用SVPWM调制算法实现。仿真显示,方案能够实现中点电压的平衡控制,具有较好的动态响应。     

直流微电网用非隔离高增益DC-DC变换器

在直流微电网中,光伏需要依靠电力电子功率变换器并网。文章提出了一种非隔离高增益DC-DC变换器,该变换器采用改进的开关电感,以提高负载的输出电压,对其连续导通模式和不连续导通模式下的稳态进行了分析,并与其它功率变换器拓扑进行了比较。最后,在Matlab仿真平台和实验样机上进行了对比,仿真和实验结果与理论分析结果基本一致。文章所提变换器与传统升压变换器相比,具有较高的电压增益,虽然该变换器使用了两个功率开关,但由于两个功率开关采用统一操作,因此控制电路简单。     

多输入交错并联Boost变换器功率分配控制策略

针对功率分配底层功能提出一种新型控制策略,该控制策略在传统的双闭环平均电流均流法上加以改进。首先电流内环修改为功率内环,将电压外环的输出除以输入电压再乘以功率分配系数作为新的功率给定值来实现功率分配功能。同时将自抗扰技术应用到电压外环提高母线电压的响应速度。最后基于模块化思想并利用氮化镓功率开关器件,搭建一台三输入交错并联Boost实验样机,其额定功率为1500 W,额定工作频率为500 kHz,峰值效率为98.3%。实验验证结果表明,在相同输入电压或不同输入电压的情况下均能实现功率分配功能,并具有良好的动态响应。     

基于BOOST变换器的MFC最大功率跟踪控制

针对微生物燃料电池存在的输出功率低、运行稳定性差等问题,建立微生物燃料电池仿真实验平台,设计改进的扰动观测最大功率跟踪控制算法,通过调节Boost变换器的占空比,对微生物燃料电池进行最大功率跟踪控制.仿真实验结果表明,改进的扰动观测最大功率跟踪控制能及时追踪微生物燃料电池的最大功率点,显著提高稳态输出功率并减小输出功率...     

A Position Stepping Method for Predicting Performances of Switched Reluctance Motor Drives

This paper presents a novel numerical method, which will be referred as the position stepping method (PSM), to predict the performances of switched reluctance motor (SRM) drives. The 2D bicubic spline is employed to generate the finite rectangular elements. The 2D bilinear spline is used to model the nonlinear magnetic characteristics in SRMs. Consequently, the conventional nonlinear first-order differential voltage equation for describing the performances of SRM drives can be simplified into an analytical expression in terms of the current with respect to the rotor position. Furthermore, the position stepping algorithm is developed according to the boundary and continuity conditions, to accurately and rapidly compute the current from the proposed current expression. Simulated and measured current waveforms are reported to validate the developed PSM. The CPU execution time required by the PSM compares very favorably with that of the analytical method. Overall, this paper provides an accurate and speedy approach to predict the currents and torques of SRM drives.     

基于模糊控制的新型永磁开关磁阻电机控制系统研究与设计

提出了一种新型永磁式开关磁阻电机。通过对传统电机结构上进行了改进,在定子上加入永磁材料,使得电机成为混合励磁电机,分析了其结构及原理等,并探讨了其调速方式,把模糊控制运用于调速系统,设计了其调速系统的软硬件,最后对其样机进行了试验,对开关磁阻电机的改进具有一定指导意义。     

Starting the Single-Phase Switched Reluctance Motor Using Rotor Shorting Rings

This article presents a technique that uses rotor shorting rings to start the single-phase switched reluctance (SR) machine, from any rotor position, in a specified direction. It also outlines how the shorting rings enable starting of the machine. Transient finite-element analysis is used to illustrate the torque-producing mechanism from the aligned position using the rotor-mounted shorting rings. It is also used to determine the optimal stator and rotor pole arcs and shorting ring design for a 200-W prototype machine. An SR drive system incorporating rotor shorting rings is evaluated, and experimental results show the effectiveness of the technique     

Online and Offline Rotary Regression Analysis of Torque Estimator for Switched Reluctance Motor Drives

A new torque estimator for switched reluctance motor (SRM) drives based on 2-D rotary regression analysis is presented in this paper. The proposed torque estimator is composed of a bicubic regressive polynomial as a function of rotor position and input current. The regressive coefficients can be computed offline or online from the torque characteristics acquired either experimentally or from numerical computation. Furthermore, a torque estimation method by taking mutual coupling into consideration is proposed. It can be seen that the estimated and experimentally obtained self-coupling and mutual-coupling torque characteristics are in good agreement with each other. In addition, the dynamic torque waveforms with and without the mutual coupling, estimated by the proposed estimator, are found to be virtually the same as those obtained from the bicubic spline interpolation for SRM drives with single-pulse voltage, hysteresis current chopping, as well as with voltage pulse width modulation control. The success of all the case studies being reported is a good validation of the usefulness and accuracy of the proposed real-time torque estimator that, as described in this paper, can be used to quickly estimate the instantaneous output torque of SRM drives.     

Piezoelectric Actuator Design and Placement for Switched Reluctance Motors Active Damping

This paper describes the design and the placement of piezoelectric actuators on switched reluctance motors by means of a genetic algorithm (nondominated sorting genetic algorithm II) for the purpose of reducing stator vibrations. Two distinct approaches are presented: one energy-related and the other based on a minimization of the resultant displacement. These methods lead to design and placement strategy for the piezoelectric actuators. A number of optimal actuators obtained using these kinds of approaches is also compared with mechanical finite-element simulations. At last, a solution is achieved in order to validate optimal placement using positive position feedback active filtering.      

Optimizing Performance in Current-Controlled Switched Reluctance Generators

The problem of choosing the firing angles for accomplishing optimal performance in current-controlled switched reluctance generators (SRGs) is examined. The optimal performance is reached with the correct balance between the criteria of high efficiency and low torque ripple. The concept of the method is based on the optimal control of turn-on and turn-off angles according to electrical load requirements and depending on rotor speed and dc-link voltage. A simple controller is proposed that on-line determines the optimal firing angles. The suggested controller does not affect the complexity of the drive and the knowledge of the magnetization curves is not required for its implementation. Simulation and experimental results are presented to validate the resulting improvements of the proposed control scheme.     

开关磁阻电机驱动系统的发展及应用

开关磁阻电机驱动（SRD）系统是继变频驱动系统、无换向器电动机驱动系统之后发展起来的一种新型的、性价比很高的节能调速控制系统。本文就SRD系统的组成、结构、工作原理、特点、国内外的发展情况进行了系统的论述,对目前SRD系统存在的问题及研究课题进行了分析。同时,为推广应用SRD系统提出了一些建议和意见,可供有关人员和企业系统了解及推广应用SRD系统做参考。     

A New Rapid Nonlinear Simulation Method for Switched Reluctance Motors

This paper presents a new rapid nonlinear simulation method for switched reluctance motors (SRMs). An exact mathematical relationship among the magnetization curves of an SRM is obtained by curve fitting the variable parameters in the Torrey model. Only geometry-based requirements are taken as input needed. Since complete magnetic characteristics are not necessary, a lot of preliminary measurements and calculations are eliminated. The dynamic performances under two operating conditions are predicted using the proposed method, and the measured results are obtained by an experimental laboratory setup. Furthermore, predictions using other two traditional models are presented for the purpose of comparison. Experimental and simulation results verify the accuracy and rapidity of the proposed method.