基于新型SVPWM的Z源逆变器研究

Z源逆变器(ZSI)通过在SVPWM普通零矢量中加入直通零矢量可以实现输入直流电压的升压变换。文章具体阐述了Z源逆变器的工作原理及其传统SVPWM实现方法,提出一种新的SVPWM直通时间分配法,该方法零矢量最大利用率高,最大升压值升高,有效提高系统工作性能。基于Matlab仿真平台,搭建了Z源逆变器的仿真模型,仿真结果验证了新型SVPWM的正确性与有效性。     

基于滑模变结构的间接矩阵变换器—异步电机控制系统研究

传统的交直交变频调速系统由于带有中间直流环节大电容或大电感,使得它体积大。间接矩阵变换器中间直流环节没有大储能元件,增加了它的紧凑性,而且间接矩阵变换器正弦电流传入,正弦电压输出,该变换器整流级与逆变级协调控制,可以实现零电流换流。滑模变结构是一种非线性的控制方法,将其应用到矢量控制系统中,可以减少对系统参数的依赖性。仿真结果表明基于变结构的间接矩阵变换器驱动异步电机矢量控制系统能够获得良好的动静态性能。     

应用于电动汽车动力系统的大功率双向DC／DC变换器

本文介绍了一种应用于电动汽车动力系统的大功率双向DC／DC变换器，该变换器中应用了一种特殊的数宁控制策略，它可以令能量在小同方向之间进行平滑的切换，并促使变换器实现自身的能量管理。作为一个实例，该变换器的优点在燃料电池汽车的研究中得以体现，下文中将具体给出该变换器的使用数据和测试结果。目前适用于24kW和70kW功率等级的双向DC／DC变换器的两种拓扑结构已经被设计出来，并得到了认可。这两种变换器具有全数字控制的过压、过流和过温保护，变换器中冷却液的温度最高可达85℃，而变换器的损耗却很低，同时功率密瞍可高达5W／cm3。变换器的特性参数和在燃料电池汽车中应用时的测试结果，将在下面予以介绍。     

一种适用于电动汽车的新型双向交错式无桥变换器

电动汽车与电网端的能量传递过程得到广泛研究。鉴于此，提出了一种适用于电动汽车电池充电器的双向交错无桥变换器。该变换器通过单元整合，取消了桥式结构。详言之，该变换器前级可等效为双向交错无桥Boost电路，以满足电网和直流母线的交互；后级可等效为双向Buck-Boost电路，以满足直流母线和汽车电池的交互。对新型双向变换器的正向和反向工作过程进行分析，同时阐述新型变换器的功率控制和电流控制策略，推出相关的控制算法。最后，通过PISM软件对该变换器进行了仿真验证。结果表明，该变换器不但具有G2V和V2G两种工作模式，并拥有较高的功率因数。     

基于PWM整流器的高效电动汽车充电机设计

介绍一种用于电动汽车电池充电机的设计实现方法.为满足高功率因数和高效的要求,采用三相PWM整流器和移相全桥变换器两级变换模式.前者基于空间电压矢量PWM直接功率控制（DPC）,实现单位功率因数;后者基于零电压零电流（ZvZCS）控制,实现高效的电能变换.以该方法设计的8 kW的充电机在大部分充电过程中,效率高于84％,输入功率因数高于99.3％.     

用于改善PFC性能的交错式三电平变换器

在不增大输入电流纹波的前提下,为改善升压型功率因数校正变换器在高频状态下的输入电流过零畸变,同时减小电感体积,降低开关器件的电压电流应力,进而提高变换器的功率等级,提出了一种交错式三电平变换器拓扑。此拓扑将交错并联技术与三电平技术相结合,弥补了交错并联拓扑只能改善输入电流过零畸变,而无法提升变换器的其他性能的不足。分析了此变换器的原理及工作情况,并进行仿真,仿真结果验证了该拓扑的有效性。     

变速恒频风力发电系统中矩阵变换器的仿真研究

双级矩阵变换器是在传统9开关矩阵变换器的基础上发展起来的一种新型矩阵式变换器,其自身的优点更适宜作为变速恒频风力发电系统中双馈电机的励磁装置.分析了双级矩阵变换器的拓朴结构和基本原理,根据其特点采用PWM控制与空间矢量调制法相结合并应用零电流换流法进行控制,并基于Matlab/Simulink对双级矩阵变换器进行了建模与仿真.仿真结果验证了控制方案的可行性和正确性.     

一种新型的基于航空电网的高功率因数校正器

研究了一种基于航空电网的高功率因数Boost PFC变换器,与以往采用的乘法器控制方法不同的是,该变换器采用新型单周期控制方法。文中分析了该变换器的工作原理,给出了系统电压环的结构模型和设计过程。仿真和实验结果证明了在输入电源频率较高场合,单周期控制Boost PFC变换器具有良好的性能。     

太阳能光伏驱动车载散热通风系统

文中设计一种太阳能光伏电池驱动的车载散热通风系统,采用光伏电池、SEPIC变换器、蓄电池和BUCK变换器的并联结构,由一片DSC芯片实现系统的功能控制与能量管理,实现光伏电池驱动车载风扇降温和为汽车蓄电池充电的双重功能。系统通过DSC芯片控制SEPIC变换器来改变光伏电池的负载特性曲线,使得环境因素变化时负载始终与电池外特性曲线相交于最大功率点,实现最大功率追踪;另外DSC芯片实时检测车内温度,控制散热风扇的转速,排出车内热空气,达到控制车内温度的效果;散热风扇运转功率来自光伏发电,且光伏发电多余电能为车载蓄电池充电。该设计提高了车辆的舒适性,具有一定节能减排的效果。通过Simulink仿真和实验验证了该设计的可行性和控制策略的有效性。     

改进软开关Buck ZCT-PWM开关电路设计及其Pspice仿真

介绍了典型的零电流转换ZCT（Zero Current Transition）PWM直流变换器的基本工作原理,分析了其存在的主开关电流应力大和辅开关硬关断的问题,提出了一种改进型开关电路。对其拓扑结构和工作原理进行了详细分析,设计了电路参数,并对其进行了Pspice仿真。结果证明此改进能够使辅助开关近似零电流关断,提高了变换器的性能。     

Development and Future Issues of High Voltage Systems for FCV

Nissan Motor Co., Ltd, has delivered the New X-TRAIL FCV 2005 Year Model to customers in April 2006 in Japan, in which a newly developed in-house fuel cell stack and 70-MPa high-pressure hydrogen storage system are installed. For fuel cell vehicles, not only the fuel cell system and the hydrogen storage system but also the high-voltage system is very important, such as a traction motor to propel the vehicle, motors that drive some devices for the fuel cell system, a second battery that stores braking energy and assists the acceleration, inverters which supply alternating current to the prescribed motors, and converters which change voltage generated by the fuel cell stack to the specific level for each subsystems to operate. X-TRAIL FCV 2005MY has increased the performance of driving range and acceleration compared to 2003MY. We have practiced using new technologies to reduce the size reduction of the high-voltage system to achieve these performance improvements, but it still needs many improvements to make fuel cell vehicles popular to the market     

A new ZVS bidirectional DC-DC converter for fuel cell and battery application

This paper presents a new zero-voltage-switching (ZVS) bidirectional dc-dc converter. Compared to the traditional full and half bridge bidirectional dc-dc converters for the similar applications, the new topology has the advantages of simple circuit topology with no total device rating (TDR) penalty, soft-switching implementation without additional devices, high efficiency and simple control. These advantages make the new converter promising for medium and high power applications especially for auxiliary power supply in fuel cell vehicles and power generation where the high power density, low cost, lightweight and high reliability power converters are required. The operating principle, theoretical analysis, and design guidelines are provided in this paper. The simulation and the experimental verifications are also presented.     

Energy Management Power Converters in Hybrid Electric and Fuel Cell Vehicles

Using a bidirectional dc-dc converter along with low-voltage energy storage for the high-voltage dc bus and traction motor drives has been a prominent option for hybrid electric and fuel cell vehicles. This paper will describe the significance of energy management power converters and their circuit topology options for efficiency, size, and cost considerations. Whether isolated or nonisolated, soft switching techniques have been widely used in high-power bidirectional dc-dc converters. Through some design examples, the component selection and circuit design optimization are discussed, and their efficiency evaluation results are also given. Major difficulties of developing a high-power bidirectional dc-dc converter are found in lack of high-power passive components and lack of multiphase dc-dc controllers. More development work needs to be done in these areas     

Fuel cells for the long haul, batteries for the spurts [electricvehicles]

Until only a few years ago, when environmentalists, automakers, and other concerned parties spoke about low-emissions vehicles, they were almost always referring to electric vehicles (EVs)-cars, trucks, and buses powered by batteries of one kind or another. Today, having so far failed in their quest for a battery that could make EVs practical, they are looking more and more to hybrid electric vehicles (HEVs), which automakers had hitherto rejected as merely an interim solution. But hybrids based on a combination of electric motors and internal combustion engines are attractive for two main reasons: they require no technology breakthroughs and no new infrastructure. They work with existing batteries since they do not rely on them for primary energy storage; rather, they can obtain fuel at any service station. An alternative to HEVs is fuel cell powered vehicles. The principles of this technology and the associated hydrogen storage issues are discussed. Other alternative fuels are briefly outlined     

PSIM-based modeling of automotive power systems: conventional, electric, and hybrid electric vehicles

Automotive manufacturers have been taking advantage of simulation tools for modeling and analyzing various types of vehicles, such as conventional, electric, and hybrid electric vehicles. These simulation tools are of great assistance to engineers and researchers to reduce product-development cycle time, improve the quality of the design, and simplify the analysis without costly and time-consuming experiments. In this paper, a modeling tool that has been developed to study automotive systems using the power electronics simulator (PSIM) software is presented. PSIM was originally made for simulating power electronic converters and motor drives. This user-friendly simulation package is able to simulate electric/electronic circuits; however, it has no capability for simulating the entire system of an automobile. This paper discusses the PSIM validity as an automotive simulation tool by creating module boxes for not only the electrical systems, but also the mechanical, energy-storage, and thermal systems of the vehicles. These modules include internal combustion engines, fuel converters, transmissions, torque couplers, and batteries. Once these modules are made and stored in the library, the user can make the car model either a conventional, an electric, or a hybrid vehicle at will, just by dragging and dropping onto a schematic blank page.     

Guest Editorial: Scanning the Issue

This special issue focuses on electric, hybrid and fuel cell vehicles. Almost all key issues and key technologies in electric, hybrid and fuel cell vehicles are covered, with a special focus on currently popular models of hybrid electric vehicles.     

Modified Pulse-Adjustment Technique to Control DC/DC Converters Driving Variable Constant-Power Loads

Multiconverter-distributed DC architectures have been utilized for power distribution in many applications such as telecommunication systems, sea and undersea vehicles, an international space station, aircraft, electric vehicles, hybrid-electric vehicles, and fuel-cell vehicles, where reliability is of prime concern. The number of power-electronic converters (AC/DC, DC/DC, DC/AC, and AC/AC) in these multiconverter electrical power systems varies from a few converters in a conventional land vehicle, to tens of converters in an advanced aircraft, and to hundreds of converters in the international space station. In these advanced applications, power-electronic converters might need to have a tight output-voltage regulation. From the output perspective, this property is highly desirable. However, since power-electronic converters are efficient, tight regulation of the output makes the converter appear as a constant-power load (CPL) at its input side. Dynamic behavior of CPLs is equivalent to negative impedance and, therefore, can result in instability of the interconnected power system. In order to mitigate the instability of the power converters loaded by CPLs, this paper presents the pulse-adjustment digital control technique. It is simple and easy to implement in application-specific integrated circuits, digital-signal processors, or field-programmable gate arrays. Moreover, its dynamic response is fast and robust. Line and load regulations are simply achievable using this technique. Analytical, as well as simulation and experimental results of applying the proposed method to a DC/DC buck-boost converter confirm the validity of the presented technique.     

Fuel cell power system and high power DC-DC converter

This paper discusses the principle and electrical characteristics of the fuel cell, designs an innovative hybrid power system, and proposes a new DC/DC converter scheme to combine the fuel cell with the storage system. An effective converter scheme for the fuel cell is obtained by analyzing the high efficient topology as well as the phase shifted pulse-width modulation. Through comparing several different control modes of converters, a 75-kW prototype system is constructed, moreover, which steady-state operating characteristics are illustrated and discussed in detail. At last, experimental results are also shown to verify the proposed scheme.     

The State of the Art of Electric, Hybrid, and Fuel Cell Vehicles

With the more stringent regulations on emissions and fuel economy, global warming, and constraints on energy resources, the electric, hybrid, and fuel cell vehicles have attracted more and more attention by automakers, governments, and customers. Research and development efforts have been focused on developing novel concepts, low-cost systems, and reliable hybrid electric powertrain. This paper reviews the state of the art of electric, hybrid, and fuel cell vehicles. The topologies for each category and the enabling technologies are discussed