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sampling

取样是指从总体中抽取个体或样品的过程,也即对总体进行试验或观测的过程。分随机抽样和非随机抽样两种类型。前者指遵照随机化原则从总体中抽取样本的抽样方法,它不带任何主观性,包括简单随机抽样、系统抽样、整群抽样和分层抽样。后者是一种凭研究者的观点、经验或者有关知识来抽取样本的方法,带有明显主观色彩。参见“随机抽样”、“非随机抽样”。[1]
  • 直流电动机测速装置

    本系统采用电动机电枢供电回路串接采样电阻的方式来实现对小型直流有刷电动机的转速测量。该系统主要由二阶低通滤波电路,小信号放大电路、单片机测量显示电路、开关稳压电源电路等组成。同时自制电机测速装置,用高频磁环作为载体,用线圈绕制磁环,利用电磁感应原理检测电机运行时的漏磁,将变化的磁场信号转化为磁环上的感应电流。用信号处理单元电路将微弱电信号转化为脉冲信号,送由单片机检测,从而达到准确测量电机的速度的要求。In this system, the sampling resistance of armature power supply circuit is connected in series to measure the speed of small DC brush motor. The system is mainly composed of second-order low-pass filter circuit, small signal amplifier circuit, single-chip measurement and display circuit, switching regulated power supply circuit and so on. At the same time, the self-made motor speed measuring device uses high frequency magnetic ring as the carrier, coil winding magnetic ring, and electromagnetic induction principle to detect the leakage of magnetic field during the operation of the motor, which converts the changed magnetic field signal into the induced current on the magnetic ring. The weak electric signal is transformed into pulse signal by signal processing unit circuit, which is sent to single chip computer for detection, so as to meet the requirement of accurate measurement of motor speed.

    标签: 直流电动机

    上传时间: 2022-03-26

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  • 基于MSP430单片机及FPGA的简易数字示波器

    数字示波器功能强大,使用方便,但是价格相对昂贵。本文以Ti的MSP430F5529为主控器,以Altera公司的EP2C5T144C8 FPGA器件为逻辑控制部件设计数字示波器。模拟信号经程控放大、整形电路后形成方波信号送至FPGA测频,根据频率值选择采用片上及片外高速AD分段采样。FPGA控制片外AD采样并将数据输入到FIFO模块中缓存,由单片机进行频谱分析。测试表明:简易示波器可以实现自动选档、多采样率采样、高精度测频及频谱分析等功能。Digital oscilloscope is powerful and easy to use, but also expensive. The research group designed a low-cost digital oscilloscope, the chip of MSP430F5529 of TI is chosen as the main controller and the device of EP2C5T144C8 of Altera company is used as the logic control unit. Analog signal enter the programmable amplifier circuit, shaping circuit and other pre-processing circuit. The shaped rectangular wave signal is sent to FPGA for measure the frequency. According to the frequency value to select AD on-chip or off-chip high-speed AD for sampling. FPGA controls the off-chip AD sampling and buffers AD data by FIFO module. The single chip microcomputer receives the data, and do FFT for spectrum analysis. The test shows that the simple oscilloscope can realize automatic gain selection, sampling at different sampling rates, high precision frequency measurement and spectrum analysis.

    标签: msp430 单片机 fpga 数字示波器

    上传时间: 2022-03-27

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  • 高精度双向DC电源电流采样电路设计

    为适应双向DC/DC功率变换的电流采样需求,一种高精度高边电流采样电路被提出。其基本思想是在功率电路的高边串入采样电阻,借助电流镜原理并引入偏置电流电路,将双向电流均转换为正向电压输出。通过理论分析与仿真结合的方法对电流镜采样原理及4种不同的偏置电流电路方案进行对比,最后通过实验数据验证了高精度高边电流采样电路的有效性。实验数据表明,该采样电路可在-25~75℃的温度工作范围内,针对-10~+10 A范围内的电流采样实现优于5%的采样精度。Current sensing plays an important role in controlling,monitoring or protection functions of power systems.To meet the current sensing requirement of bidirectional DC/DC converters,a high-accuracy bidirectional current sensing circuit is proposed.The proposed current sensing circuit inserts a resistor in the path of the current to be sensed,while the current mirror and biased current circuit are introduced.Therefore,the bidirectional current can be expressed by positive voltage.By theoretical analysis and simulation,the sampling theory is analyzed and four biased current circuits are compared.At last,experimental results verified the proposed method.It is demonstrated that the proposed current sensing circuit can achi...

    标签: 双向DC电源 电流采样

    上传时间: 2022-04-22

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  • 基于DSP28335的永磁同步电机调速系统设计

    基于DSP28335的永磁同步电机调速系统设计摘要(中英文)     本控制系统的设计是为了实现基于TMS320F28335的永磁同步电动机的调速系统,并把它引用到全电动注塑机当中。本系统使用SVPWM的控制方法,通过采样电机电流和旋转变压器的位置信息,实现速度、电流双闭环控制。通过TMS320F28335的硬件浮点处理核心,实现应用于永磁同步电机的浮点算法,去取代过去的定点算法,提高代码效率。 Abstract: The control system is designed to realize TMS320F28335 based on the permanent magnet synchronous motor speed control system, and put it to quoting all electric of injection molding machine. The ystem of the control method used SVPWM, through the sampling motor current and rotating transformer 1.        引言1.1 设计背景及目的    本永磁同步电机调速系统是全电动注塑机的其中一个应用部分。全电动注塑机凭借着其节约能源、清洁、噪声少、速度控制效果好、精度高、可重复性高、成本低等众多优点,成为了当下高端注塑机发展的一个方向。    全电动注塑机的所有运动机构都采用交流伺服电动机驱动,一个稳定高效的永磁同步电动机驱动方案成为了全电动注塑机性能的一个总要部分。本次设计以适用于全电动注塑机的永磁同步电动机控制系统为目标进行设计,采用TI公司的TMS320F28335作为控制核心。凭借TMS320F28335高速的运算能力,适用于电动机控制的各种外设,以及TMS320F283XX特有的硬件浮点运算能力,进行永磁同步电动机的调速控制系统的设计。

    标签: dsp28335 永磁同步电机

    上传时间: 2022-05-08

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  • 高级PID控制算法.

    Simulation can provide a lot of information about what the system is doing. We canadd the effect of different element, like Encoder resolution, ADC sampling rate, etc and understand how does it affect the system. Another benefit is the possibility to slow down the process, to gain insight on what happens of fast systems or, vice versa, speed up slow process.Because National Instruments is a unique company in the fact the we provide a fullhardware solution couple with a full development platform, we can use this tools in very particular ways For example, it is possible to combine the LabVIEW Control Design and Simulation Module along with the FPGA module to quickly prototype a controller. One of the main benefits of this approach is that there is no need to compile the FPGA code, which allows for a quick algorithm design turnaround and debugging.

    标签: pid控制

    上传时间: 2022-07-20

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