基于TL494的微型车载逆变器设计

针对汽车内部直流电源不能用于交流用电器的问题,设计了一款基于脉宽调制芯片TL494的微型车载逆变器。该逆变器采用DC-DC变换和DC-AC逆变两级结构,前级完成直流升压,后级选择脉宽调制（PWM）控制方式,将直流电压逆变为220V/50Hz的方波交流电。其中,DC-DC变换器先通过推挽逆变电路和高频变压器将12V变换为22V交变方波,再经快恢复二极管整流得到22V直流电。另外,该逆变器提供了一个标准USB接口,可以为具有USB接口的手机等设备充电。     

TMS320VC5502图像传输系统的USB接口扩展

介绍了DSP（数字信号处理器）图像传输系统中USB接口扩展的软硬件设计,对USB物理层和链路层的数据传输管理通过USB2．0接口芯片CY7C68001完成,并由DSP芯片TMS320VC5502进行控制,通过编程完成USB设备枚举、数据读写和中断处理等过程。系统采用批量传输方式与Pc机进行高速数据传输,在Windows系统下为用户进行图像传输建立友好的图形界面,对其他系统的接口扩展设计有一定的参考价值。     

基于无线USB技术的数据传输系统

基于USB控制器芯片CY7C68013A和无线射频芯片nRF2401,设计了一种无线USB接口的数据传输系统,并详细介绍无线USB接口的软硬件设计。与采用多芯片实现USB接口的系统相比,使用单芯片完成USB接口的设计,提高了系统的可靠性。下位机由FPGA作为主控芯片,使得硬件设计更加灵活,提高了硬件部分的可移植性。该系统具有USB接口所支持的可热插拔、即插即用的特点,并且实现了数据的无线传输,无需布置通信电缆。     

NEC电子全球首推支持USB3．0的主控系统芯片

NEC电子日前完成了支持USB3．0的系统芯片的开发,全球率先推出USB3．0系统芯片“uPD720200”,并于今年6月起开始提供样品。USB3．0是在电脑、数字家电、键盘、鼠标等电子产品领域广泛使用的接口规格USB的下一代规格。     

基于FPGA与USB 2.0接口的红外图像采集系统设计

以FPGA为核心处理器,完成了中波热像仪输出红外图像的实时采集与存储系统设计。系统主要由USB固件程序、FPGA控制程序和上位机软件组成,通过对工作在Slave FIFO 模式下的USB2.0接口芯片CY7C68013A内部FIFO进行控制,实现了USB接口的高速数据传输。应用结果表明,该系统具有数据传输速度快、采集数据准确等特点。     

基于USB总线的投影仪控制系统

USB总线是计算机外设接口的发展趋势,越来越多的设备使用USB接口代替RS 232接口.区别于传统的RS 232总线控制投影仪的通讯方式,提出了一种方案,将RS 232接口转换为USB接口接入PC机,使用USB总线控制投影仪工作,使系统具有了USB总线方便、灵活的特点.在系统实现过程中,PC机对设备的识别和控制投影仪命令的传输都由固件完成.另外,文章分析了USB总线的通信原理,同时研究了系统软硬件设计方案.     

基于芯片CH375的USB总线和ISA总线转接的实现

USB总线因其便捷的特性使得其应用越来越广泛,电子市场上带有USB接口的设备也越来越多,USB总线取代传统的老式接口必将成为一种趋势。而ISA总线是工业标准总线架构,在工控领域中历史悠久,是最早的系统级总线。 ISA总线如今在工业控制领域的主要作用就是扩展中低速设备接口,因为工控领域中要控制的设备往往非常多,所以ISA总线在工业领域中仍然起着非常重要的作用。本文的主要目的是利用CH375芯片完成USB总线到ISA总线的转接。     

基于FPGA的USB设备控制器设计

嵌入式系统向小型化和低功耗的方向发展要求减小板级设计的面积提高速率。基于嵌入式系统日益增长的规模和性能以及高速USB协议的要求,对USB设备控制器的系统进行相关模块的划分并利用Verilog硬件描述语言设计出高速USB接口IP核。经过仿真验证,该IP核符合高速USB协议的要求,满足系统对USB接口数据的传输需求。     

基于CH372的CAN总线适配器系统的设计

本文介绍了一种基于新型USB接口芯片CH372的CAN总线网络适配器系统的设计,提出了一种使用USB接口实现CAN总线网络与计算机连接的方案。利用芯片CH372可在不了解任何USB协议或固件程序甚至驱动程序的情况下,轻松地将并口或串口产品升级到USB接口。该系统在工业现场较之以往的系统,可以更加灵活、高速、高效地完成大量数据交换,并可应用于多种控制系统之中,具有很大的应用价值。     

CH378主机方式USB存储设备写入速度提升方法研究

摘要：CH378接口芯片完成对USB存储设备的读写操作,实现大容量数据的便携存储。系统采用MCU控制CH378接口芯片来完成对USB存储设备的读写操作。并对CH378主机方式USB存储设备的写入速度方案进行比较,从而设计一种新的方案对CH378主机方式USB存储设备写入速度有较大程度的提升,经过测试验证,USB存储设备的写入平均速度达517.9KB/s,对同类开发具有很好的参考意义,可以方便地集成于各种测试系统。     

间歇式能源发电系统无功补偿技术的研究

针对间歇式能源发电系统的特点和无功需求,提出了将无功补偿与风力并网发电相结合的设计方案,通过计算得出了间歇式能源发电系统中电缆和变压器无功损耗.本文利用Mat-lab/Simulink搭建了具有无功补偿功能的并网变流器的仿真模型,并采用有功无功解耦控制和SPWM控制方法,补偿系统所需无功以及有效抑制动态电压波动.最后,仿真结果验证了风力并网变流器在向电网提供有功功率的同时也能够提供一定容量的无功功率,提高系统功率因数,有效抑制电网电压波动.     

A novel high-performance voltage regulator for single-phase ACsources

Regulation of load voltage in single-phase applications is becoming an important issue for critical loads. This paper presents a novel high-performance single-phase voltage regulator which has a common arm between the rectifier and inverter, and adopts an appropriate switching strategy. The proposed voltage regulator employs six switches and can be implemented by only one three-phase inverter module. The proposed voltage regulator has the capability of delivering sinusoidal input current with unity power factor, good output voltage regulation, and bidirectional power flow. For these purposes, a fully digital controller is designed and implemented using a TMS320F240 digital signal processor. In addition, a novel low-cost AC capacitor is also presented. This type of capacitor requires two DC capacitors and two diodes, enabling low-cost and compact manufacturing. Consequently, the complete voltage regulator system, which is mainly suitable for an uninterruptible power supply as well as reactive or nonlinear loads, can be constructed compactly and inexpensively. Experimental results are presented to verify the feasibility of the proposed voltage regulator system     

多电平单元串联电压源型变频器高压电源瞬时失电连续运行研究

高压变频调速系统现场应用复杂，工艺多样。在重要的大型工业系统中，高压电源系统有双备用，紧急互投等功能，当变频器对大功率的电机供电时，如果高压电源进行切换，将出现0．1S～1．5s左右的失电间隔，要求变频器在失电间隔中能正常工作，且转速波动较小，达到系统在失电期间不出现剧烈振荡。对于多电平单元串联电压源型变频器，当通过对功率单元电容值的加大，PWM输出占空比减小的方法提高失电连续运行性能，其效果均不理想。在经过大量论证后，采用特殊的DSP控制逻辑，并利用旋转系统中的飞轮动能转换，取得实现变频器在高压瞬时失电时保持稳定运行。     

A novel single-stage full-bridge buck-boost inverter

A novel single-stage full-bridge series-resonant buck-boost inverter (FB-SRBBI) is proposed in this paper. The proposed inverter only includes a full-bridge topology and a LC resonant tank without auxiliary switches. The output voltage of the proposed inverter can be larger or lower than the dc input voltage, depending on the instantaneous duty-cycle. This property is not found in the classical voltage source inverter, which produces an ac output instantaneous voltage always lower than the dc input voltage. The proposed inverter circuit topology provides the main switch for turn-on at ZCS by a resonant tank. The nonlinear control strategy is designed against the input dc perturbation and achieves well dynamic regulation. An average approach is employed to analyze the system. A design example of 500 W dc/ac inverter is examined to assess the inverter performance and it provides high power efficiency above 90% under the rated power.     

基于坐标变换的间隙性功率并网系统解耦控制与设计

针对逆变器电流环的有功电流和无功电流存在耦合的情况,文中采用电流的解耦控制,达到独立控制逆变器的有功功率和无功功率;针对逆变器直流侧电压容易波动,文中采用双环控制,稳定逆变器直流侧的电压。搭建了MA-TALAB/SIMULINK系统仿真实验平台,通过间歇性能源输入逆变器功率变化的实验,验证了该逆变器能独立控制输出的有功功率和无功功率,并且保证了直流侧电压的稳定。     

正弦波输出的单相逆变电源设计

逆变电源是将直流电能转变成交流电能的变流装置,是太阳能、风力等新能源发电系统中的重要设备.本文主要介绍了正弦波逆变电源的主电路设计、单片机数字控制系统设计等内容.主电路包含单相全桥逆变电路、升压变压器和LC滤波电路等,数字控制选用dsPIC30F2010 PIC单片机产生SPWM波形,经IR2110芯片驱动MOS管,再经全桥逆变和LC低通滤波电路,最终输出正弦波交流电压.依据设计方案制作了实验样机,实验结果证实样机能输出纯净的正弦波电压,能够满足设计指标要求.     

Z-source inverter for adjustable speed drives

This paper presents a Z-source inverter system and control for adjustable speed drives (ASD). The Z-source inverter employs a unique LC network to couple the inverter main circuit to the diode front end. By controlling the shoot-through duty cycle, the Z-source can produce any desired output AC voltage, even greater than the line voltage. As results, the new Z-source inverter system provides ride-through capability under voltage sags, reduces line harmonics, and extends output voltage range. Simulation results are presented to demonstrate the new features.     

A dual two-level inverter scheme with common mode voltage elimination for an induction motor drive

Pulse-width modulated (PWM) inverters are known to generate common mode voltages which cause motor bearing currents in the induction motor drives. They also result in leakage currents which act as sources of conducted electromagnetic interference in the drive system. The common mode voltage generated by a conventional three-level inverter can be eliminated by switching only the voltage space vectors which do not produce the common mode voltage. This paper presents a PWM switching strategy to eliminate common mode voltage using the open-end winding configuration for the induction motor. The switching strategy presented in this paper, does not generate any alternating common mode voltages in the drive system and hence the electrostatic coupling of the common mode voltage, which results in the bearing currents and the leakage currents, is avoided. The proposed scheme is devoid of neutral point voltage fluctuations and does not require neutral point clamping diodes, when compared to the common mode elimination scheme based on the conventional three-level inverter topology. Also, the present scheme uses a single dc-link with half the voltage compared to the conventional three-level inverter based scheme.     

Three Phase Three-Level PWM Switched Voltage Source Inverter With Zero Neutral Point Potential

A new three phase three-level pulsewidth modulation (PWM) switched voltage source inverter with zero neutral point potential is proposed. It consists of three single-phase inverter modules and each module is composed of a switched voltage source and inverter switches. The major advantage is that the peak value of the phase output voltage is twice as high as that of the conventional neutral-point-clamped PWM inverter. Thus, the proposed inverter is suitable for applications with low voltage sources such as batteries, fuel cells, or solar cells. Furthermore, three-level waveforms of the proposed inverter can be achieved without the switch voltage unbalance problem. Since the average neutral point potential of the proposed inverter is zero, a common ground between the input stage and the output stage is possible. Therefore, it can be applied to a transformerless power conditioning system. The proposed inverter is verified by a PSpice simulation and experimental results based on a laboratory prototype.     

基于dsPIC的PV逆变器的一种改进结构及其实现

针对目前PV光伏并网发电系统的核心逆变器的现状、结构和控制方法进行了详细的分析,从电网、PV系统及用户的需求出发,指出传统的单级全桥逆变器普遍具有不能处理较宽的输入PV电压,且需要重型工频升压变压器等缺点。在此基础上,本文创新设计并实现了一种基于单级全桥逆变器的并联耦合改进结构。实测证明这种并联耦合反激结构可以有效地减小通过大容量输入电解电容的纹波电流的RMS,从而延长电容的寿命;还可减小输出电流的纹波,从而降低输出电流的THD（谐波失真）;还可适应较宽的输入电压,减小交流纹波,减小磁芯,同时可以提供较高的额定输出电流等优点。