逆电流

The controller estimates a three-phase motor current value by using a current detection value detected by the current sensor and a rotor rotation position, and controls the inverter by using on the motor current estimation value.

这里，用电流传感器检测出的电流检测值和转子旋转位置推定3相的电动机电流值，用该电动机电流推定值控制逆变器。

By the means of theory, simulation and experiment, the second part of this paper is then analyzed which is on the equivalent output resistance and inductance of the selected inverter and the effect to the output voltage"s amplitude and phase caused by the different values of the inverter"s component. It is concluded that by selecting certain precision level components, the difference of the output voltage amplitude is much greater than that of the output voltage phase.

其次通过理论、仿真和实验分析了本文所采用的电压电流双闭环瞬时控制方式逆变器的等效输出阻抗和两台逆变器器件差异对输出电压的幅值差和相位差的影响，从而得出选用一定精度的器件，两台逆变器输出电压的幅值差比相位差大得多的结论。

By adding an equivalent harmonic impedance in the branch circuit of power grid, this HAPF could force all the harmonic currents flow into passive power filters, which resulting in eliminating harmonic contamination more effective. And using the capacitive feature of PPF in the fundamental frequency, this HAPF could compensate fixed-capacity reactive power without increasing APF's burden. Moreover, in order to decrease APF's cost, the fundamental voltage will largely be endured by capacitor in view of the series resonance circuit tuned at the fundamental frequency, so the APF just bears little harmonic voltages.

其基本工作原理是：有源部分等效于在电网支路中串联了一个谐波阻抗，该谐波阻抗对基波电流不起作用，而对谐波电流产生很大阻碍作用，迫使谐波电流流入无源滤波器，从而达到滤除谐波的目的；同时新型注入式混合有源滤波器还充分利用了无源滤波器的无功补偿功能，在不增加有源部分容量的前提下，可以提供一定容量的无功功率；由于有源部分承受的电网基波电压不大，也没有基波电流流入，因此逆变器容量小，初期投资较小。

A novel compensating method is provided utilizing the stator currents decoupling and the linearization of the angle interval of current vectors.Based on the performance index of voltage utilization ratio, total harmonic distortion, switching loss and etc, various PWM methods have been introduced.

本文详细分析了逆变器输出的非线性特性及影响因素，重点对零电流夹断现象及其机理进行深入的研究，针对电流过零区间的非线性畸变提出了利用定子电流解耦以及电流矢量角度区间线性化的补偿方法。

Based on the needs of system control strategy and the output of the active inverter, a switch function method was adopted to build the average model of switch cycle for the active inverter in order to accurately analyze operation characteristic of active inverter, a feed forward and double loop control strategy is put forward, its double control includes a inductor current inner loop control and instantaneous voltage outer loop control.

中文摘要：为准确分析有源逆变器的运行特点，根据系统控制策略的需要，在考虑了有源逆变器输出的基础上采用开关函数法建立了有源逆变器的开关周期平均模型。提出一种前馈加双环控制的控制策略，它的双环控制包括一个电感电流内环控制和一个瞬时电压外环控制。

A detailed analysis of the main circuit introduction, control method and working principle of the direct-drive wind energy conversion system are given to introduce the two important parts a of this paper: First part is the control method of the multiple boost convertor, the important instantaneous current control method of this paper is given through the analysis of the main circuit structure, control method and working principle. Then a steady-state analysis for low-frequency, a high-frequency component analysis, and a closed-loop tracking performance analysis for dynamic response are provided to analyze the method proposed; And the second part is the control method of invertor.

在系统变流器整体结构分析的基础上，引出本文重点研究的两个变流环节的控制：第一部分是系统升压斩波器的控制，通过分析相关主电路结构、原理，建立了数学模型，引出本文重点研究的瞬时值控制策略的概念和具体实现，并对升压斩波器的瞬时值控制策略进行了详细的高频、低频模型分析和稳态、动态性能分析；第二部分是系统并网逆变器的控制，通过对逆变器主电路的数学建模和控制要求分析，研究了并网逆变器的瞬时值控制策略，包括电感电流控制内环和直流电压控制外环的具体设计和实现方法。

A novel zero-voltage and zero-current resonant pole soft-switching inverter was proposed to achieve zero- voltage and zero-current switching simultaneously when main power devices turn-on and turn-off. Therefore, turn-on capacitive losses could be reduced for devices which the intrinsic capacitor value cannot be neglected. Additionally losses caused by the tail current can also be reduced, when IGBTs are used as main switches.

提出一种新型的零电压零电流谐振极型软开关逆变器，可以在主功率器件开通和关断时，同时实现零电压和零电流，因此对于内部电容不能忽略的器件，可减小容性开通损耗，当绝缘栅双极型晶体管(insulated gate bipolar transistor，IGBT)作为主功率器件时，也可减小拖尾电流引起的损耗。

Research and Design of Push-Pull Forward and Soft-Switching Circuit

本文结合推挽正激直流变换器和高频脉冲直流环节逆变器的优点，提出了一种适用于低压大电流输入场合的逆变器，并对构成这种逆变器的电路拓扑、SPWM控制策略、稳态原理特性进行了深入的分析研究。

In order to choose suitable voltage space vector and achieve current-follow-control,it samples stator current with constant frequency.According to the motor-model,optimize-controlled coltage vector is computed at the next sample moment to control actual next stator current so as to follow next reference.

为了选择合适的电压空间矢量，实现电流跟踪控制，以固定频率采样定子电流，按电机模型计算出下一采样时刻逆变器的最优控制电压矢量，从而控制下一时刻实际定子电流去追踪下一时刻参考电流。

Taking the design subway coach as an exam- ple, the article points out that it's an ideal schema to use current source inverter with re- verse conducting for common inverter to be minified.

本文首先以地铁动车设计为例，指出采用逆导晶闸管电流源逆变器是普通逆变器实现小型化的一个较好的方案。

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。