瞬时电流

Transient and surge are the instant aberrance of the voltage and electric current on the simple alternating current wave circuit.

瞬变和浪涌是正弦交流波电路上电压与电流的一种瞬时态的畸变。

AIM: To explore the effects of brucine on transient outward potassium current of ventricular cardiomyocytes of rats.

目的： 探讨马钱子碱对大鼠心室肌细胞瞬时外向钾电流(transient outward potassium current，Ito)及其动力学的影响。

Later, it makes some comparison with four kinds of modulation technique, and finally, it implements the three-level PWM switching power amplifier with the PWM technique. The power of the amplifier is 2kVA, and the frequency bandwidth is 10～3kHz. In the thesis, the author designs and makes the hardwares of the switching power amplifier. The hardwares contain power inverter rank circuit, control system circuit based on DSP, drive and isolation circuit, and protective circuit. The thesis also analyses the potential safety problems and put forward some solutions for the problems. Furthermore, the thesis accomplishes the software design of the control system, and successfully debugs it. The methods of designing higher power ampilfier are also discussed in the thesis. It analyses the feasibility of the methods, outlines the way of how to design higher power switching power amplifier, and does some experiments with the method of switches-parallelling.

根据电动振动试验系统对开关功放的要求，提出了以电感电流瞬时值控制技术为基础的三电平脉宽调制开关功放的设计方案，并通过系统仿真进行了原理性论证；然后设计并制作了开关功放的硬件，包括功率转换电路，基于DSP的控制电路，驱动、隔离电路以及保护电路；针对开关功放数学模型不易得出的特点，细致分析了模糊自适应PID控制方法，在此基础上编写了控制程序；研制出一台功率为2kVA，通频带为10～3kHz的三电平脉宽调制开关功放；论文中还探讨了实现大功率开关功放的方法，分析了各种方法的可行性，给出了实现大功率开关功放的思路，并进行了并联开关管实现大功率开关功放的实验。

Harmonic current; reactive current; instantaneous reactive power theory; matlab simulation

谐波电流；无功电流；瞬时无功功率理论；Matlab仿真

The MATLAB simulation software is used to model the harmonics detection circuit, which is based on the instantaneous reactive power theory.

通过对基于瞬时无功功率理论的一种谐波电流检测方法的研究，利用MATLAB仿真软件建立了相应的仿真电路，就其中的低通滤波器对谐波电流检测效果的影响进行了仿真研究。

Simulation and experimental results indicate that for the SPWM inverter based on instantaneous output voltage feedback control,the fundamental open circuit output voltage incr...

仿真和实验结果表明，对于采用瞬时输出电压反馈控制技术的SPWM逆变器，其输出电压在空载时随着死区时间的增加而增加，负载电流超过临界电流后其输出电压随死区时间增加而下降；其阻性负载时的外特性曲线是一条先下降后上升的曲线。

The result indicate that: the electrodeposition of zinc on nickel and tungsten substrates involves instantaneous three-dimensional nucleation. The coating is the best when the current density is 4mA/cm2 and the temperature is 80 ℃. The coating by the method of the impulse electrodeposition is better than the direct current electrodeposition. Especially when f is 100Hz, ton/toff is 2/8 and J is 8mA/cm2, the coating is clean and uniformity. The crystal size is nearly 0.3μ m .

结果表明：阴极反应为准可逆反应，锌离子在镍电极和钨电极上形核是三维瞬时形核半球形扩散长大过程，直流电流密度为4mA/cm2，温度为80 ℃时，镀层质量最好；脉冲电沉积得到的镀层要优于直流电沉积得到的镀层，尤其在脉冲宽度为2ms，脉冲间隔为8ms，电流密度为8mA/cm2时，得到的镀层光滑而均匀，颗粒大小接近0.3μm。

Then, aiming at harmonic current problem of single-phase circuit, I predigest the triphase instantaneous harmonic and reactive power theory to be used in detecting harmonic current of single-phase circuit.

然后，针对单相电路中的谐波电流问题，对三相的瞬时无功功率理论进行简化，使其应用于单相的谐波电流检测当中。

Firstly, harmonic detection method using ip,iq algorithm, which is based on the instantaneous power theory proposed by H.Akagi, is introduced briefly and is extended to detect positive or negative sequence of arbitrary order harmonic in single-phase system, three-phase three-wire system or three-phase four-wire system.

首先，本文简要介绍了基于瞬时功率理论的谐波电流检测方法——i_p，i_q算法，并将之推广应用于单相系统、三相三线制系统和三相四线制系统中任意次数谐波的正序、负序有功、无功分量的检测，大大拓宽了该优良瞬时谐波检测算法的应用范围。

The control signals of the PWM rectifier are obtained by comparing the current of AC side with triangular wave (or saw-tooth wave) directly, which can implement the steadiness of the voltage of DC side and unit capacity factor of the system. At the same time, harmonic component of the system is abstracted through Instant Reactive Power Method, which can be smoothed by Integrated Learning Boost Converter Control.

本文采用重复学习Boost变换技术，利用滑模变结构控制技术对单相PWM整流器恒频Boost变换进行了分析，提出将交流侧电流直接与三角波相比较得到开关控制信号的方法，实现直流电压恒定不变及系统单位功率因数；同时，利用瞬时无功功率法分析系统谐波，并在谐波域内使用重复学习的控制方法，结合Boost变换技术，有效滤除系统谐波有功电流。

I didn't watch TV last night, because it .

昨晚我没有看电视，因为电视机坏了。

Since this year, in a lot of villages of Beijing, TV of elevator liquid crystal was removed.

今年以来，在北京的很多小区里，电梯液晶电视被撤了下来。