协变和逆变的区别对于张量的计算尤为重要，这往往会出现混合方差。
The distinction between covariance and contravariance is important for computations with tensors, which often have mixed variance.
最后就是对协变和逆变的支持了。
本文主要分析了在线互动式ups电源的充电、逆变的基本原理。
The paper mainly analysed the charge and invert principle of line-interactive UPS.
通过把高阶张量写成若干逆变和协变矢量的乘积，直接从变换入手，给出了定义高阶张量协变导数的另一种方法。
This paper discusses another way, which is rewritten as product of a few contravariant vectors and covariant vectors, to define higher order tensors covariant derivative through transformations.
本文介绍一种应用于IGBT逆变式点焊机的点焊控制器。
A controller applied to IGBT inverter spot welding machine is introduced in this paper.
将直流变为频率可调的交流电流就称逆变。
The DC into AC current adjustable frequency that the inverter on.
伏能士知道如何降低这些费用的答案—有源逆变技术。
Fronius has the answer to the problem of how to lower these costs - Active Inverter Technology.
本论文主要介绍了所研制的单片机控制逆变埋弧焊机的组成结构和控制原理。
The component parts and control principle of pulsed SAW inverter power source are mainly introduced in the paper.
实验结果显示，采用逆变焊机进行焊接，焊点的平均强度有所提高，飞溅率和未焊合率均有大幅度降低。
The experiment shows that by using inverter spot welding, the average intensity of the welded spot is increased while the splash rate and the incomplete penetration rate are descend.
调节为基础，利用快速可控硅做开关元件，研制的一台新型等离子弧切割电源——输出直流100a逆变切割电源。
M. adjusted, by the use of high speed SCR gate, a new convening power source with output of 100a for plasma are cutting is developed.
以应用于燃料电池逆变功率变换的阻抗源逆变器为例，分析了其工作原理和控制方法。
To describe the operating principle and control, this paper focuses on an example: a Z-source inverter for dc-ac power conversion needed in fuel cell applications.
本文最后搭建了一个基于多电平矢量发生的逆变实验系统，制作了一台用矢量发生器驱动的1.5KW的多电平变换器实验样机，在样机上得到了较为理想的波形。
An experiment prototype of 1.5kw three-level inverter has been manufactured, which is driven by "based on FPGA vector generator". We finally got ideal wave in this experiment system.
比较电压偏差及其变化率，查询模糊控制表，调节逆变脉宽，可实现电压及电流的理想控制。
According as compare of voltage deviation and its variable ratio, optimal control of voltage and current is realized with querying fuzzy control sheet and adjusting adverse variable pulse width.
本文论述了可控硅逆变器逆变角影响串级调速装置功率因数的基本原理。
This paper discusses the basic principle which the inverted firing angle of thyristor inverter has the influence on power factor of a cascade connected device.
SVPWM具有较高的直流电压的利用率，开关损耗小，从而实现了高性能的逆变输出。
SVPWM technique have many good qualities, such as less pulsating torque, high usage of DC bus voltage, less switching loss, better high-speed regulation performance.
注意尽管上面的例子只展示了对于代理类型如何声明协变和逆变。对于接口这样做也是不难的。
Note that although the above examples show how to declare covariance and contravariance for delegate types, it's not different to do so with interfaces.
采用先进的逆变技术，工作频率高，体积小，重量轻，便于携带。
Adopt advance inverter technology, with high working frequency; lt's compact, light, easy to carry.
采用先进的逆变技术，工作频率高，体积小，重量轻，便于携带。
The use of inverter technology, high frequency, small size, light weight, easy to carry.
本文对四段全控桥电路在整流、逆变工况的微机实时控制进行了理论阐述和物理模拟试验。
This paper concerns the microcomputer-based real-time control of four-step controlled bridge which works both in the mode of rectifier and inverter.
电力行业1994年开始组织逆变焊机的选型工作。
Inverter Welding machine type - selecting work was carried out in power trades from 1994.
本文简要介绍了现代逆变技术的概念、分类及现代逆变系统基本结构。然后详细描述了车载电网中逆变器的功能实现和参数设计。
The concept, classification and system structure of modern inverter are reviewed briefly, and the function realization and design parameters of the inverter on vehicle power are described in detail.
结果表明：这种新型的大功率埋弧逆变自动焊机有着广阔的应用前景。
The result shows that this newfashioned high-power machine of submerged-arc welding inverter has wide prospect of application.
该装置由逆变主电路和以arm 7单片机at91 M 55800为核心的测控系统组成。逆变主电路实现了频率和功率均可调的超声频交流电的输出。
This device consists of inverter major circuit and monitoring system based on ARM7 chip AT91M55800. The main circuit produces power supersonic AC output with adjustable frequency and changeable power.
介绍了该逆变式弧焊机的构成，工作原理及特点。
The paper introduces the configuration, principle and characteristics of the inverter for arc welder.
本文在对光伏并网逆变装置进行理论分析的基础上，研制开发了一套基于C8051F040单片机的并网逆变装置样机。
Based on making theoretic analysis of grid- connected photovoltaic inverter, a set of grid-connected photovoltaic sample inverter is developed based on singlechip of C8051F040.
本文在对光伏并网逆变装置进行理论分析的基础上，研制开发了一套基于C8051F040单片机的并网逆变装置样机。
Based on making theoretic analysis of grid- connected photovoltaic inverter, a set of grid-connected photovoltaic sample inverter is developed based on singlechip of C8051F040.
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