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该金属探测器是以单片机为核心,通过霍尔传感器测量线圈磁场的变化间接测量电压的变化,和基准电压值相比较,来判断是否探测到金属。 相似文献
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为了解决现有闭环霍尔电流传感器需要双电源供电,无法直接应用在单电源系统的问题,设计了一种单电源供电电压输出型的高精度闭环霍尔电流传感器。理论说明了其设计方案,磁路上考虑了磁环材料、几何尺寸及开口宽度,并用有限元对其进行了仿真,电路上应用由双运放组成的桥式驱动电路驱动反馈线圈,采用电压检测芯片将反馈电流转化为电压输出,为验证方案可行性?制作了量程为±50A的实验样机。实验结果表明,该霍尔电流传感器灵敏度可达40mV/A,其线性度和精度分别为0.15%和0.25%,适用于单电源系统。 相似文献
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本文介绍的电路可使电脑中的无刷风扇的转速低至每秒两三转。无刷风扇的电机一般由一个产生外部旋转磁场的电枢和环绕的永磁转子构成。电枢线圈通过其内部电路连续切换电流方向以使转子旋转,并用霍尔器件测量出转子磁铁的位置。虽然电机速度可通过降低电源电压来降速,但是这样会因电压值过低而使电子装置停止 相似文献
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本文使用波形发生器产生震荡冲击电压,对震荡冲击电压造成的电路局部放电的原理和影响进行了分析和研究,并且通过建立等效电路模型的方法,对相关参数进行分析,并列出表达式对参数进行推导和计算;同时,本文还设计了高频电流传感器,通过高频电流传感器可以方便的测量电路中局部放电脉冲,根据高频电流传感器对积分电阻和线圈匝数变化时,频率特性产生的变化进行分析。将传感器通过相关仪器进行校准,并且根据对震荡冲击电压进行分析、测量的基础上,构建了一套系统对局部电路放电脉冲进行测量,并且通过建立仿真模型进行模拟试验。根据对试验得到的数据进行分析,结果表明本文设计的系统对源干扰具有明显的抑制作用,对局部放电脉冲可以进行有效的提取,对相关领域的研究具有一定的价值。 相似文献
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提出了一种利用霍尔传感器对电网电流进行非接触测量的方法 ,推导出了用霍尔传感器测量高压大电流的数学模型 ,在三相并行输电下 ,理论上推导出总磁场公式 ,并确定出检测方案。对传感器部分的电路结构进行了论证 ,利用单片机进行标度变换和数字显示。 相似文献
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A MEMS piezoresistive magnetic field sensor based on a silicon bridge structure has been simulated and tested.The sensor consists of a silicon sensitivity diaphragm embedded with a piezoresistive Wheatstone bridge,and a ferromagnetic magnet adhered to the sensitivity diaphragm.When the sensor is subjected to an external magnetic field, the magnetic force bends the silicon sensitivity diaphragm,producing stress and resistors change of the Wheatstone bridge and the output voltage of the sensor.Good agreeme... 相似文献
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《Applied Superconductivity》1999,6(6):247-257
A new design concept of the axisymmetric magnet system generating the very high pulsed magnetic field which is superimposed on the bias magnetic field of the superconducting magnet is presented. The pulsed magnet consists of two coaxial coils which are wound in opposite directions. The geometry of both pulsed coils, i.e. the working (inner) one and the compensating (outer) one is designed in such a way that the mutual coupling between the small pulsed magnet and the outer superconducting magnet is practically zero. This configuration prevents the rise of the high induced voltage on the current leads of the superconducting magnet when the pulsed magnet is being energised, hence resulting naturally in protection of the system (superconducting magnet and the current source) against possible damage. Further, it is predicted that the stray field of the pulsed magnet, which gives rise e.g. to the eddy currents in the winding of the superconducting magnet, is considerably decreased. The simple theory enabling the design of the geometry of the compensating pulsed coil is derived. The advantages of this new concept are demonstrated on the results of the theoretical analysis using, as an example, one of the pulsed coils that were designed and fabricated in the Clarendon Laboratory, in connection with the Oxford Instrument superconducting magnet (Clarendon hybrid outer) which can generate a steady magnetic field up to 10 T in a room temperature working space with a diameter of 240 mm. 相似文献
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Computer-aided design of an axially symmetrical magnetic circuit and its application to electron-beam-focusing devices 总被引:1,自引:0,他引:1
《Electron Devices, IEEE Transactions on》1972,19(6):782-797
This paper presents a method of computer simulation useful for analysis of an axially symmetrical magnetic circuit with exciting coils, magnetic poles, and permanent magnets. The vector magnetic potential is obtained by the use of the well-known successive over-relaxation method, so that devices having magnetic hysteresis characteristics can be analyzed easily and accurately. In this program, the magnetization intensity distribution within the magnet is taken into account. The new computer programming system is applied to a magnetic shielding hollow sphere, a bar magnet, a ring magnet, and a periodic permanent-magnet structure for traveling-wave tubes, and the flux distribution for these magnetic circuits is shown. The results are seen to be in good agreement with theoretical and experimental values. 相似文献
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研究了线圈间距、匝数、个数以及不锈钢套筒对脉冲磁体产生磁场的影响规律。在储能电容和电压不变的前提下,研究结果表明:增加线圈间距会导致磁感应强度降低,磁力线包络增大,但总电流达到峰值时刻减小;增加线圈匝数,峰值电流明显减小,会降低磁感应强度,但有利于抑制磁力线包络;增加并联线圈个数,有利于产生较长的均匀区,但是在供能一定的条件下,磁场强度有所降低,同时总电流达到峰值时刻减小。总体来看,在一定均匀区长度的设计要求下,减少单个线圈匝数,增加并联线圈个数,能够得到磁感应强度更大、均匀性更好的磁场,但要考虑线圈承载电流的能力。另外,不对称的阴阳极金属结构会导致磁场不对称分布,且磁感应强度达到峰值时刻要晚于总电流达到峰值的时刻。 相似文献
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Anashin V. Bulygin A. Labutsky S. Mejidzade V. Mikhailov S. Pupkov Y. Rouvinsky E. Sukhina B. Kalbreier W. Kouba G. Schirm K.M. Weisse E. Konstantinov Y. Kosjakin M. Peregud V. 《Applied Superconductivity, IEEE Transactions on》2002,12(1):120-124
Two injection transfer lines, each about 2.8 km long, with 51 and 107 degree horizontal deflection, are being built to transfer protons at 450 GeV from the Super Proton Synchrotron (SPS) to the Large Hadron Collider (LHC). A total of 360 dipole magnets are required; they have been produced in the framework of the contribution of the Russian Federation to the construction of the LHC. The classical dipoles, built from laminated steel cores and copper coils, have a core length of 6.3 m, 25 mm gap height and a nominal field of 1.81 T at a current of 5270 A. The magnet design was made in collaboration between CERN and BINP. An unusual design has been chosen for the coils to cope with the limited voltage from the available power supplies. All magnets in each of the two lines will be powered in series. The coil is composed of overlapping, but electrically insulated, half coils of 3 1/2 turns each. Thus, the power connections for IN and OUT are placed on opposite magnet ends. Short copper braids are used to connect all upper or lower half coils in series and the whole string can be powered without power consuming cable links running alongside the magnets. Precautions are taken to avoid transmission line effects and hazards from differences in voltage between upper and lower half coil. Advantages and drawbacks of this concept are discussed as well as results of the acceptance test including mechanical, electrical and magnetic field measurements. Fabrication and measurement of the magnets at BINP, with the half core production subcontracted to EFREMOV, have been finished in June 2001. 相似文献
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《Applied Superconductivity, IEEE Transactions on》2006,16(3):1918-1923
This paper describes the characteristics analysis of a high-Tc superconducting (HTSC) power supply considering flux creep effect, and also presents its operational characteristics through experiments. The power supply can be employed to charge an HTSC magnet. An HTSC power supply consists of two heaters, an electromagnet, a Bi-2223 solenoid, and a series-connected Bi-2223 pancake load. The pancake load was fabricated by connecting four double pancake coils in series. In the experiments, two cases of the pumping period, which correspond to 8.5 and 17 s, were used with an electromagnet of 331 mH and a dc heater current of 0.8 A. A region of the superconducting tape with a buried heating coil can be switched by means of its temperature change. In order to measure the pumping-current with respect to the magnet flux changes, a hall sensor was installed at the center of the Bi-2223 pancake load. The experimental observations have been compared with the theoretical predictions. In this experiment, the pumping-current has reached about 22.9 A. 相似文献
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对磁场中对称结构的霍尔元件的输出特性进行研究,提出一种差分霍尔效应加速度测量方法。基于线性霍尔元件和圆柱形永磁体设计加速度测量模型,两个霍尔元件与磁体构成对称互补结构,以差分方式输出信号电压。建立加速度与输出电压的线性关系,实现以非接触的方式测量加速度。模型的对称互补式设计,减小了非线性因素对测量的影响,改善了输出线性度。差分式电压输出,能够抑制共模干扰和零点漂移,并提高了信号幅度。对模型进行线性模拟实验,实验结果符合理论结论。数据分析显示,测量方法具有较高灵敏度和线性度。 相似文献
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《Applied Superconductivity, IEEE Transactions on》2009,19(4):3645-3652