燃料电池发电系统结构与逆变控制研究

本文着眼于楼宇供电用燃料电池发电系统的研究，针对中等容量（几千瓦至几百千瓦）的功率变换装置，分析其运行特点和对系统结构和控制的基本要求，提出具体的系统方案与控制策略，满足楼宇供电燃料电池发电系统的并网发电和独立运行的要求。最后给出了一个5kVA的燃料电池发电装置试验结果。     

单相LCL并网逆变器双电流闭环控制仿真研究

采用LCL滤波方式的并网逆变器具有高频衰减特性,滤波效果优于单电感滤波方式。但是LCL滤波器为无阻尼三阶系统,易发生谐振。传统的解决方法是在电容支路串入电阻增加系统阻尼,虽然可以减小谐振,但却增加了额外损耗。文中采用并网电流和电容电流双闭环的方法增加系统阻尼,对电流双闭环方案进行系统建模和稳定性分析,并用MATLAB软件进行仿真验证。结果表明该方案可抑制系统振荡,提高系统稳定性。     

电流源变频器电流补偿仿真研究

针对电流源型变频器中存在的大量谐波.在电流型变频器的基础上加入一个电压型逆变电路,提出了一种谐波电流的补偿方法。该方法首先通过滤波电路检测谐波电流.然后补偿电路产生与谐波电流相位相反的电流注入负载.以减小负载电流谐波.此外.补偿电路还可以提高变频调速系统运行性能以及可靠性.仿真结果说明了分析的正确性     

DC Bus Compensation for a Sinusoidal Voltage-Source Inverter With Wave-Shaping Control

This paper presents a study on the effects of different parameters on the dc bus voltage of a single-phase voltage-controlled voltage-source inverter (VCVSI) with conventional load-voltage root-mean-square (rms) feedback control and a wave-shaping controller (WSC). It is shown that the load-voltage rms feedback control and the WSC require compensation for the fluctuations in the dc bus voltage caused by the battery and lead-wire resistance and the lead-wire inductance. The dc-bus-voltage compensation is shown to provide performance improvements, including better load-voltage regulation and less load-voltage distortion. The mathematical modeling, computer simulations, and experimental results based on a 2-kVA single-phase full-bridge VCVSI are presented.      

A Low Cost Utility Interactive Inverter for Residential Fuel Cell Generation

This paper presents the development of a single-phase utility-interactive inverter for residential power generation to meet the specifications laid down for the 2005 Future Energy Challenge Competition sponsored by U.S. DOE and IEEE. The proposed inverter system is capable of working in both stand-alone and grid-connected mode. A control scheme for implementing both modes of operation is presented, which has simple structure with smaller number of sensors. The proposed control algorithm including the whole system control is implemented on a low cost, fixed-point DSP TMS320F2812. The experimental results from a 1 kW prototype show that the proposed inverter system exhibits not only low THD grid current during the grid-connected mode and well regulated inverter voltage during the stand-alone mode, but also smooth and automatic transfer between the two modes of operation.     

三相并网逆变器的双环控制策略研究

由于对高频谐波的抑制效果明显好于L型滤波器,因此LCL滤波器在电流源控制的并网逆变器中应用越来越广泛。而针对该类型的并网逆变器的控制策略更为复杂,为了简化控制策略一种基于电流双环的并网控制方案被提出来。与电压电流的双环控制器设计方法不同,设计电流双环控制器参数时除了考虑内外环控制器的相互影响以外,还需要考虑双环控制器带来的降阶和少自由度问题。因此本文在介绍基于高阶极点配置的电流双环控制器设计方法的基础上,重点分析在电流双环控制带来的少自由度的情况下如何合理的设计控制器参数。实验结果表明,根据该方案设计的控制器参数能够使三相并网逆变器安全、可靠运行且具有较快的动态响应速度。     

Mathematical Modeling of a Digital Current Control Loop for Electrical Drives

Analysis of a digitally controlled current loop in a drive system is performed by a newly developed z-transform method that serves both the discontinuous and continuous case, and is verified by an interactive computer program based on system modeling. The assumption made is that the drive system has a sufficiently high mechanical inertia so that the current loop responds before the speed has changed. It is shown that under such conditions the transient response in discontinuous conduction can be approximated by a series of rectangular pulses, the heights of which are calculated by assuming that the current-time areas for the actual current increment and the equivalent pulse are equal. The results of the z-transform method agree well with those obtained from ditigal modeling.     

Linear Phase Lead Compensation Repetitive Control of a CVCF PWM Inverter

This paper presents a simple and efficient linear phase lead compensation repetitive control scheme for engineers to develop high-performance power converter systems. The linear phase lead compensation helps a repetitive controller to achieve faster convergence rate, higher tracking accuracy, and wider stability region. In the proposed scheme, the phase lead compensation repetitive controller is plugged into generic state-feedback-controlled converter systems. Its comprehensive synthesis, which involves principle, analysis, design, modeling, implementation, and experiments, is systematically and completely presented in great detail. A complete series of experiments is successfully carried out to verify the solution.     

三相并网逆变器LCL滤波器的简明设计

LCL滤波器以其较好的滤波性能被广泛地用于并网逆变器,但无阻尼时系统产生谐振,给系统的稳定性控制带来困难。文中在建立三相并网逆变器数学模型的基础上,采用基于d,q同步旋转坐标系的电网电压定向控制策略,利用被动阻尼抑制谐振提高了并网逆变器的稳定性能。文中给出了被动阻尼LCL滤波器的详细设计方法,并比较其与单L滤波器的滤波效果,运用Matlab/simulink建立系统模型并进行仿真,实现了单位功率因数并网。     

一种基于Z源逆变器的燃料电池汽车变换器

在燃料电池汽车中,电能转换是一个核心问题。结合燃料电池的特性,简要说明了燃料电池汽车中现有变换器的不足。同时,为了克服传统燃料电池汽车电能变换器两级结构固有的不足,进一步提高其稳定性,提出了一种性能较高的Z源逆变器,分析了该结构的工作原理,采用了一种新型的具有直通零矢量的三相电压空间矢量调制方法,介绍了其工作特点以及直通零矢量的产生方法,进行了相关的仿真实验。仿真结果表明,该电路结构能够达到较高的性能要求,适合在燃料电池汽车上应用。     

基于DSP闭环控制的单相逆变器的研究

基于DSP的闭环控制逆变,采用TMS320F2812作为控制器.文章通过对DSP编程产生的PWM和SPWM,以光耦隔离分别来驱动高频逆变桥和工频变换器,同时分析了逆变桥中开关损耗,通过改进算法,提高了转换效率.     

Digital Current Control of a Voltage Source Converter With Active Damping of LCL Resonance

Inductance–capacitor–inductance (LCL)-filters installed at converter outputs offer higher harmonic attenuation than L-filters, but careful design is required to damp LCL resonance, which can cause poorly damped oscillations and even instability. A new topology is presented for a discrete-time current controller which damps this resonance, combining deadbeat current control with optimal state-feedback pole assignment. By separating the state feedback gains into deadbeat and damping feedback loops, transient overcurrent protection is realizable while preserving the desired pole locations. Moreover, the controller is shown to be robust to parameter uncertainty in the grid inductance. Experimental tests verify that fast well-damped transient response and overcurrent protection is possible at low switching frequencies relative to the resonant frequency.     

直线电机控制系统中电流环的优化设计

分析了直线电机的控制原理,设计了电机控制系统的软硬件方案,基于SVPWM原理,对电流环伺服控制策略进行了研究,并对抑制推力波动和电机驱动中逆变器的死区补偿问题做了一些探讨,最后详细介绍了直线电机中电流环的软件实现方法.经过实际运行,证明所采用的方案和控制策略具备高精度、易控制等特点,优化了电机控制系统.     

矢量控制电流环的内模解耦控制

电机矢量控制虽然实现了励磁电流和转矩电流解耦,但交流电机内部M轴和T轴之间存在交叉耦合电压及转子温升造成矢量控制条件的破坏.提出采用定子电流解耦的内模控制,推导出其设计过程和控制器型式,通过数字仿真论述了感应电动机定子电流控制系统采用解耦内模控制,可有效抑制干扰及模型失配对输出的影响,增强系统对给定信号的跟踪能力.     

Parameter Design of a Two-Current-Loop Controller Used in a Grid-Connected Inverter System With LCL Filter

LCL filters offer a better choice of attenuating switching frequency harmonics. However, in a grid-connected system, an LCL filter may cause resonance which is a disaster for the system's stability. In order to solve the problem, a two-current-loop control strategy, which includes grid-current outer loop and filter-capacitor-current inner loop, is adopted here. The implementation of this strategy is easy, but the tuning procedure is complex since the outer and inner controllers cannot cooperate well if the parameters of the controllers are not suitable. There is no literature which mentions a method to help give out accurate parameters of the controller. The difficulty of designing the controller is that only two feedbacks cannot provide complete information of a three-order LCL filter. A specific method is proposed in this paper to design the controller. The advantage of this method is to provide a way to maximize the utilization of the two feedbacks to get good system performance through parameter determination. The practicability of the method is tested by using bode diagram, and the antidistortion ability of the system is analyzed. Finally, experimental results verify the availability and correctness of the proposed method.     

基于滞环电流控制的串联型双Buck逆变器

为了使分布式发电系统更有效更稳定地利用自然资源,文章提出了一种适用于风光发电系统(WPGS)的逆变器模型,它由两个双Buck结构串联组成。通过理论分析和模型仿真研究了该逆变器的工作过程。系统由电压外环和电流内环调节输出电压和输出功率,滞环电流控制消除了斜坡交截SPWM控制所需的的偏置电流,提高了效率,增强了系统稳定性。仿真结果表明该逆变器具有克服桥臂直通的优点,可以在两输入电压不稳的情况下为负载提供稳定的电压,具有一定的实用价值。     

无刷直流电机的电流闭环控制

分析了BLDCM的换相转矩脉动,指出了引起转矩脉动的主要原因是:关断相电流的下降速度大于开通相电流的上升速度,得到了减小电机低速运行时非换相电流脉动的方法,该方法的原理是令换相期间脉宽调制信号的占空比?等于两倍的稳定运行时脉宽调制信号的占空比α1(2α1=α法).在此基础上,提出了基于三相电流的相电流闭环控制.指出只有三相电流控制才能有效控制相电流.分别通过仿真验证了基于三相电流的相电流闭环控制能够有效的减小非换相电流的脉动.     

一种新型恒频滞环电流控制策略研究

并联型有源电力滤波器的变环宽滞环电流控制方法是根据电流幅值的变化适时调整滞环宽度,可有效保证滤波器的补偿性能,控制开关器件的开关频率。在传统的变环宽滞环电流控制算法的基础上,加入了电流限幅和频率PI反馈控制环节,限制了较大电流的波动,提高了频率的控制精度,以及有源电力滤波器的电流补偿性能。Matlab仿真结果表明,采用新型恒频滞环电流控制算法进行电流跟踪补偿时,系统的电流总畸变率小于采用传统变环宽滞环电流控制算法时的总谐波畸变率。     

Strategy for Airflow Control of Cathode in Proton Exchange Membrane Fuel Cell

There are two important objectives for airflow control in proton exchange membrane fuel cells （PEMFCs）. One is to keep the desired excess ratio（to provide sufficient reactant airflow） to ensure fast transient response arid to minimize auxiliary power consumption, and the other one is to control the cathode pressure in stack within an acceptable range. In reality, the big inertia of stack＇s airflow-supplying activator limits the bandwidth of air-flow supply loop, which makes the first objective difficult to achieve, and another difficulty is that airflow is coupled with the cathode pressure in stack, which make it uneasy to keep the pressure unchanged in case of airflow perturbation. In order to overcome these difficulties, three dependant controllers are presented in this paper to control airflow, deeouple the cathode pressure in stack from airflow and stabilize the cat bode pressure in stack respectively. The effectiveness of these controllers is proven by subsequent simulation and test results.     

斜坡补偿电路在峰值电流控制模式中的应用

介绍了电源驱动电路在峰值电流控制模式下的工作原理,分析了占空比D>50%时驱动电路产生振荡和不稳定的原因,从理论上论述了电感电流的斜率,占空比与系统稳定性之间的关系,运用斜坡补偿的方法实现电源驱动电路在峰值电流控制模式下的稳定,给出了斜坡补偿的基本原理,设计步骤以及补偿电路,最后给出以UC3842为控制芯片的反激式变化器斜坡补偿电路设计实例。仿真与实验结果表明,斜坡补偿电路能够实现峰值电流控制开关电源在占空比D>50%时稳定工作,保证了系统的稳定性和抗干扰能力。