逆电流

Basing on analyzing the work principle of the current control methods, it can be given the detailed derivation process basing on the grid and inverter pulse width modulation algorithm and the duty cycle of the instantaneous current control.

在分析了电流控制方法工作原理的基础上，给出了基于瞬时电流控制的并网逆变器的脉宽调制算法和占空比的详细推导过程。

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 constitutive equation between current density vector and electric field strength vector is tranformed into s-domain by the principle of Laplace transform,and the inverse Laplace transform is adopted for the explicit equations between them in time-domain. Finally through exponential time stepping,the FDTD iteration equations are obtained,which can be easily solved in discrete-time-domain.

该方法是将电流密度矢量与电场强度矢量之间的本构方程基于拉普拉斯变换原理转到复频域，然后再逆变换到时域得到它们之间显式的方程，最后再结合指数差分，得到离散时域的显式的FDTD迭代方程，解决了本构方程中电流密度矢量的分量相互耦合而不易直接离散的困难。

Under all conditions,the difference of output current between inverters is less than 2 % of rated current.

同时具有较好的负载适应性，在各种情况下，各逆变电源的输出电流差小于额定电流的2%。

The unified discrete iterative map model of peak current and valley current controlled buck, boost, and buck-boost converters is established, and the unified piecewise smooth iterative map and their corresponding characteristics equations are also derived.

本文建立了峰值电流和谷值电流控制Buck，Boost，及Buck-Boost变换器的统一离散迭代映射模型，并导出了统一的分段光滑迭代映射方程及特征值方程，通过数值仿真得到了占空比变化时的正、逆分岔图和Lyapunov指数谱。

Including setting up system platform and measuring structure of the rigidity of pretension spring of the solenoid valve, designing the dynamic electric-current driver on the basis of power sink principal, variable pulse width modulation of voltage boosting and inversion technology, realizing the intelligence controlover the control parameters, satisfying the diversity requirement towards the dynamic feature experiment of the solenoid valve; furthermore, testing system software is developed, and filtering is conducted over the signals of armature displacement response and driving current educed from the experiment using wavelet analysis technology.

构建了系统台架和电磁阀预紧弹簧刚度测量机构，设计了基于功率吸收原理和可变脉宽升压逆变技术的电磁阀动态电流驱动器，实现了对驱动器参数的智能控制，满足了对电磁阀动态特性试验的多样性要求。开发了测试系统软件，提出了基于小波分析的方法，对试验所得衔铁位移响应信号和驱动电流信号进行了滤波。

A state variable feedback based system control approach, which indirectly controls load voltage by means of controlling the supply current, is proposed, thus the problem that the undamped DC transient component of supply current, which is caused by the linking inductance between power supply and power loads under PI control mode, is solved.

分析了仅由1套逆变器构成的并联型综合电能质量调节器的结构特点和控制目标，提出了一种基于状态变量反馈的系统控制方法，通过控制电源电流来间接控制负载电压，很好地解决了常规比例–积分控制时电源和负载间的连接电感所导致的供电电流直流暂态分量不衰减的问题。

The dissertation focuses on reviewing the proposed different hysteretic damping force versus velocity models of the MRD, and further proposes a generalized model which decouples the current control dependence on magnetic field and the hysteron dependence on exciting nature and is easy to derive the inverse model.

论文在综合分析国内外学者提出的MRD各种滞环阻尼力-速度特性模型基础上，提出了MRD的依赖于直流磁场的电流控制特性和依赖于激励性质的滞环算子可分离的半主动控制特性，建立了相应的电流控制与滞环特性相分离的一般化模型，且易于求解其逆模型。

Using this method, wide dimming range can be achieved with narrow frequency range and constant DC link voltage. And the lamp current keeps perfect sine wave all the time, which means low lamp current crest factor is obtained. Its validity is verified by simulation and experiment.

本章最后提出了一种基于T型滤波器的新型的调光方法，采用此方法可以在保持逆变器直流母线电压和开关占空比不变的情况下，只需很窄的频率范围就能达到非常宽的调光范围，而且在整个调光范围内灯电流都基本上是完美的正弦波，这就意味着可以始终保持很低的灯电流波峰因数，仿真和实验结果充分验证了它的优点。

Besides, in order to eliminate the effect of grid voltage distortion or disturbance on output current, decoupling control is employed to further improve the quality of output current.

此外，为了消除电网电压畸变或扰动对逆变器输出电流的影响，系统中引入了电网电压前馈解耦控制，改善了系统输出电流的质量。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。