基于DSP的无刷直流电机控制器中电流检测系统

针对以TMS320F2812 DSP为核心的无刷直流电机控制系统,分析了电流检测环节的关键技术,充分考虑了在电流检测、电压跟随以及电压抬升等环节存在的问题,利用电流互感器、运算放大器和可调电阻给出了解决方案,实现了强弱电的隔离以及电流与电压的转换.通过C语言编程,给出了计算被测电流有效值的具体软件程序,并利用Matla...     

大入地短路电流造成发电厂局部电势超标的研究

新建大型发电厂单机容量超过GW,投网运行台数超过2台.若厂区内发生不对称接地短路故障,则可能入地电流过大,造成设计人工接地装置接地电阻值大于A类电气装置允许接地电阻值上限;且校核局部接触电势和跨步电势超出设计规范要求.因此,根据实际工程特点,提出局部增设小网孔水平均压带且铺设砾石提到地面电阻率.结果方案满足工程设计标准.     

交流采样技术在嵌入式状态监测系统中的应用

为实现嵌入式状态监测系统对电站输出交流信号的实时监测,结合工程实际选用交流采样技术对信号进行采样,并利用适合的数字测量算法计算信号的真有效值和频率.通过仿真测试比较,快速傅里叶变换算法能在频率稳定和频率波动的情况下以较高的精度对异步采样信号进行技术参量求取,同时有效抑制了低次谐波和直流信号的干扰.将交流采样技术应用于嵌入式状态监测系统,不但利用嵌入式处理器的快速性和实时性克服了交流采样运算复杂的缺点,而且交流采样技术反向节省了系统的硬件开销,实现了优势互补.     

基于DSP的数字化点焊智能恒流控制系统研究

随着电阻点焊技术的广泛应用,对焊接控制的稳定性、实时性和精确性提出了更高要求.设计了以TMS320C2812为核心的点焊智能控制器.所设计的控制系统由硬件和软件两部分组成,硬件部分主要包括主控制器和辅助电路,软件系统采用模块化设计,采取带白调整函数的模糊规则控制策略实现恒流控制.实验证明,控制系统达到了很好的恒流控制效果,完全满足设计与实际使用要求.     

三相双Buck宽变频逆变器研究

介绍了两态滞环电流控制型双Buck逆变器(Dual Buck Inverter,简称DBI)的电路结构和工作原理,提出了一种滞环电流控制型逆变器输出滤波器的解耦设计方法.在此基础上进行了三相组合式实验研究,通过数字控制技术实现了逆变器系统360～800 Hz宽变频输出.通过三相6 kVA原理样机验证了该逆变器系统在全频率范围具有良好的输出电压波形和较高的效率,因此应用前景广阔.     

基于LCL滤波器的并联有源电力滤波器电流闭环控制方法

并联有源电力滤波器(active power filter,APF)需要具有较高的补偿带宽和较低的开关纹波含量。LCL滤波器由于可以兼顾低频段增益和高频段的衰减,是APF输出滤波器的较好选择,但LCL滤波器是3阶系统,增加了控制难度。通常应用于APF电流控制的瞬时值反馈内环结合重复控制外环的双环控制性能较好,但其主要是针对单电感滤波器进行设计,难以直接应用于LCL滤波器控制。提出一种简单的内环方案,利用数字控制固有的一拍计算延时进行LCL滤波器的稳定控制,只需一个反馈量,结构简单;由于内环有效地改善了系统的特性,作为外环的重复控制器的设计相对简单。基于LCL滤波器的双环控制方案赋予了系统较高的稳态补偿精度和快速的动态响应。实验结果证明了所提出控制方法的有效性。     

High speed SOI CMOS image sensor with pinned photodiode on handle wafer

We have fabricated SOI CMOS active pixel image sensor with pinned photodiode on handle wafer. The structure of one pixel is a four-transistor type active pixel image sensor, which consists of a reset and a source follower transistor on seed wafer, and is comprised of a photodiode, a transfer gate, and a floating diffusion on handle wafer. The photodiode could be optimized for better quantum efficiency and low dark currents because the process of a photodiode on handle wafer is independent of that of transistors on seed wafer. Most of the wavelengths are absorbed within the visible range, because the optimized photodiode is located on the handle wafer. The response time of SOI CMOS active pixel sensor was about 2 times faster than that of bulk CMOS active pixel image sensor.     

A Low-Loss Built-In Current Sensor

This paper presents a novel built-in current sensor that uses two additional power supply voltages besides the system power supply voltage, and that is constructed by using a current mirror circuit to pick up an abnormal IDDQ. It is activated only by an abnormal quiescent power supply current and minimizes the voltage drop at the terminal of the circuit under test. Simulation results showed that it could detect 16-A IDDQ against 0.03-V voltage drop at 3.3-V VDD and that it reduced performance degradation in the circuit under test. It is therefore suitable for testing low-voltage integrated circuits. Moreover, we verified the behavior of the sensor circuit implemented on the board by using discrete devices. Experimental results showed that the real circuit of the sensor functioned properly.     

Why ‘Current Mode’ Does Not Guarantee Good Performance

It is often said that there is a fundamental difference between current-mode and voltage-mode circuits. This conjecture is discussed in technical and philosophical terms, and it is shown that there is no such performance difference to be found, and that it is not possible to make a clear divide between voltage mode and current mode.And yet performance differences appear in the literature. It is shown that they come from the different design practices of the current-mode and the voltage-mode research groups. The conclusion of this paper is that the practical knowledge of the current-mode research groups should be re-integrated into main-stream IC design, and that all propaganda of the type current-mode is better than voltage-mode should be stopped immediately.     

F-TRIA01: A Fast Bipolar Transimpedance Amplifier

This paper describes a new transimpedance amplifier for fast current pulses delivered by high energy particle detectors. The choice of a bipolar technology allowed a 100 low input impedance and a rise time down to 1 nS. The fully differential current mode architecture provides an excellent linearity and a large versatility as for its transimpedance, bandwidth and power consumption.