1) discrete variable frequency
离散变频
1.
This paper studied some technical problems arising during the soft starting of three-phase asynchronous motors with heavy loads,which was achieved by means of discrete variable frequency.
针对采用离散变频方式实现三相异步电动机重载软起动过程的一些技术问题进行了分析和研究。
2.
Based on characteristics of discrete variable frequency soft starting, a novel speed measuring method using residual voltage after AC dump was proposed, and its counting formula, analysis of errors were presented.
针对离散变频技术调压调频的特点,提出了基于电动机失电残余电压的测速方法,推导出了转速计算公式,并进行了误差分析。
3.
To solve the key problem of soft starting based on discrete variable frequency,the influence of different trigger-ing modes on the phase of first-harmonic of generated voltage was investigated and the selection of frequency steps and the switching process were analyzed.
针对离散变频软起动方法中的关键问题,研究了不同触发方式对分频电压基波相位的影响,并分析了各离散频段的选取及切换过程。
2) Discrete Frequency-Control
离散变频
1.
Research of Discrete Frequency-Control Soft Start for three-Phases Asynchronous Motor;
三相异步电动机离散变频软起动的研究
2.
Discrete frequency-control soft starting technique that has the circuit of electronic soft starter modifies amplitude and frequency of voltage by controlling the power frequency half-wave in software, so it can meet the demand of starting current and torque.
离散变频软起动技术不改变电子软起动器的电路,在软件上对工频半波进行触发控制实现变压变频,在不提高成本的前提下满足了电机对起动电流和起动转矩的要求。
3) discrete chirp-Fourier transform
离散调频傅立叶变换
1.
An autofocus algorithm based on the discrete chirp-Fourier transform(DCFT)is proposed to image the accelerating targets.
针对加速转动目标,本文提出了一种基于离散调频傅立叶变换(discrete chirp-Fourier trans- form)的自聚焦算法。
4) frequency-shifted DFT
频移离散傅里叶变换
5) Discrete frequency voltage control method
离散变频调压技术
6) discrete spectrum
离散频谱
1.
A new method is put forward for automatically identifying and modifying the parameters of the two close frequency components in discrete spectrum based on ICM.
在理论概括比值法原理的基础上 ,提出一种新的自动识别和修正离散频谱中两邻近谱峰参数的方法。
2.
A new method to identify and correct the parameters of intensive frequency components automatically in the discrete spectrum was presented.
提出一种自动识别和校正离散频谱中邻近谱峰参数的方法·该方法不仅保留了比值法计算简单的特点 ,而且既能识别间距不到一个频率分辨率的密集频率成分 ,又能校正峰间距为 1～ 6个频率分辨率的邻近谱峰参数 ,从而与比值法相辅相成 ,形成一套完整的离散频率信号分析方法·数值仿真结果证明了方法的有效性
3.
At present, the single harmonic component and far spaced multi frequency components in discrete spectrum can be identified by using the methods of spectrum correction, and its frequency, phase and amplitude can be corrected automatica.
目前频谱校正理论已经能准确地自动识别出离散频谱中的单频成分和间隔较远的多频率成分 ,并自动校正其频率、幅值和相位 ;对多频成分谱线干涉中的单频成分能自动判定 ,且能用参数识别法对两个密集频谱进行校正 ;对于密集频率成分信号 ,可用频谱细化的方法 ,将发生谱线干涉的各谱峰分离开 ,再进行识别和校正。
补充资料：离散时间周期序列的离散傅里叶级数表示
(1)
式中χ((n))N为一离散时间周期序列，其周期为N点，即
式中r为任意整数。X((k))N为频域周期序列，其周期亦为N点，即X(k)=X(k+lN)，式中l为任意整数。
从式(1)可导出已知X((k))N求χ((n))N的关系
(2)
式(1)和式(2)称为离散傅里叶级数对。
当离散时间周期序列整体向左移位m时,移位后的序列为χ((n+m))N，如果χ((n))N的离散傅里叶级数(DFS)表示为,则χ((n+m))N的DFS表示为
式中χ((n))N为一离散时间周期序列，其周期为N点，即
式中r为任意整数。X((k))N为频域周期序列，其周期亦为N点，即X(k)=X(k+lN)，式中l为任意整数。
从式(1)可导出已知X((k))N求χ((n))N的关系
(2)
式(1)和式(2)称为离散傅里叶级数对。
当离散时间周期序列整体向左移位m时,移位后的序列为χ((n+m))N，如果χ((n))N的离散傅里叶级数(DFS)表示为,则χ((n+m))N的DFS表示为
说明：补充资料仅用于学习参考，请勿用于其它任何用途。
参考词条