霍尔传感器测速原理

霍尔传感器测速原理 现代检测技术 测控11-2班 范国霞 1105070202 绪论 现代技术关于速度的测量方法多种多样，其中包括线速度和角速度两个方面，速度和转速测量在工业农业、国防中有很多应用，如汽车、火车、轮船及飞机等行驶速度测量;发动机、柴油机、风力发电机等输出轴的转速测量等等。其中有微积分转换法，线速度与角速度转换方法，时间位移方法等等，下面我所介绍的是霍尔传感器对于速度的测量方法。霍尔式传感器是基于霍尔效应原理的传感器. 关键字:霍尔效应，霍尔传感器 based on datum point will be provided in units, according to construction drawings with the main axis for establishing horizontal control network of controlled axis. For effective implementation of measurement and control during the construction process, the master axis extends beyond the limits of excavation, set a permanent control points. Set up benchmarks to require stability, reliability, visibility, and TIC investment survey has been completed, checking with each other, its relative error is less than 1/30000 on a side, angle-measuring error is less than 7. " Strengthening network protection. 2. the Foundation, basement axis control: cushion construction has been completed, the master axis measured by theodolite voted on the cushion and cushion down to throw measured on the surface of the master axis is checked, error controla Red flag, as a basis for binding reinforcement and formwork. Foundations, basement finished, the master axis projection measuring on the basement to the roof, gave off the axis of the wall or the line of control (outside the axis 200mm) basis for the formwork. 3. the main structural axis control: Foundation construction has been completed, check the master axis points after a collision-free motion and displacement, the master axis projection measuring on the basement to the roof, close checking correct-by-construction drawings released axis, let out wall lines and basic axis displacement and checking each axis dimension. Each template is complete, double-check on the axis of the wall. After the floor has been poured, using theodolite vertical method, each floor is subject to axis, first floor, using extension methods or lateral borrowed 霍尔传感器 霍尔传感器是基于霍尔效应的一种传感器。1879年美国物理学家霍尔首先在金属材料中发现了霍尔效应，但由于金属材料的霍尔效应太弱而没有得到应用，随着半导体技术的发展，开始用半导体材料制成霍尔元件，由于他的霍尔效应显著而得到了应用和发展。在了解霍尔传感器之前先了解一下什么是霍尔元件以及它的基本特性。 霍尔元件的结构很简单，它是由霍尔片、四根引线和壳体组成的，如图1所示。 图1 霍尔片是一块矩形半导体单晶薄片，引出四根引线:1、1ˊ两根引线加激励电压或电流，称激励电极;2、2ˊ引线为霍尔输出引线，称霍尔电极。霍尔元件的壳体是用非到此金属、陶瓷或环氧树脂封装的。在中，霍尔元件一般可用两种符号示，如图1(b)所示。 霍尔元件的基本特性 (1)额定激励电流和最大允许激励电流 当霍尔元件自身温度升高10?所流过的激励电流成为额定激励电流。以元件允许最大温升为限定的激励电流称为最大允许激励电流。因霍尔电势随激励电流增加而线性增加，所以使用中希望选用尽可能大的激励电流，因而需要知道元件的最大允许激励电流。 (2)输入电阻和输出电阻 激励电极间的电阻称为输入电阻。霍尔电极输出电势对电路外部来说相当于一个电压源，其电源内阻即为输出电阻。 (3)不等位电势及不等为电阻 当霍尔元件的激励电流为I时，若元件所处位置磁感应强度为零，则它的霍尔电势应该为零，但实际不为零。这是测得的空载电势称为不等位电势。 (4)寄生直流电势 再外加磁场为零、霍尔元件用交流激励时，霍尔电极输出除了交流不等位电势外，还有一直流电势，称为寄生直流电势。 (5)霍尔电势温度系数 在一定磁感应强度和激励电流下温度每变化1?时，霍尔电势变化的百分率称为霍尔电势温度系数。他同时也是霍尔系数的温度系数。 based on datum point will be provided in units, according to construction drawings with the main axis for establishing horizontal control network of controlled axis. For effective implementation of measurement and control during the construction process, the master axis extends beyond the limits of excavation, set a permanent control points. Set up benchmarks to require stability, reliability, visibility, and TIC investment survey has been completed, checking with each other, its relative error is less than 1/30000 on a side, angle-measuring error is less than 7. " Strengthening network protection. 2. the Foundation, basement axis control: cushion construction has been completed, the master axis measured by theodolite voted on the cushion and cushion down to throw measured on the surface of the master axis is checked, error controla Red flag, as a basis for binding reinforcement and formwork. Foundations, basement finished, the master axis projection measuring on the basement to the roof, gave off the axis of the wall or the line of control (outside the axis 200mm) basis for the formwork. 3. the main structural axis control: Foundation construction has been completed, check the master axis points after a collision-free motion and displacement, the master axis projection measuring on the basement to the roof, close checking correct-by-construction drawings released axis, let out wall lines and basic axis displacement and checking each axis dimension. Each template is complete, double-check on the axis of the wall. After the floor has been poured, using theodolite vertical method, each floor is subject to axis, first floor, using extension methods or lateral borrowed 霍尔传感器测速原理: 电流的测量采用磁平衡式霍尔电流传感器 传感器可测量从直流到100kHz的交流量在自动测控系统中,常需要测量和显示有关电参量。目前大多数测量系统仍采用变压器式电压、电流互感器,由于互感器的非理想性,使得变比和相位测量都存在较大的误差,常需要采用硬件或软件的方法补偿,从而增加了系统的复杂性。 采用霍尔检测技术,可以克服互感器这些缺点,能测量从直流到上百千赫兹的各种形状的交流信号,并且达到原副边不失真传递,同时又能实现主电路回路和电子控制电路的隔离,霍尔传感器的输出可直接与单片机接口。 因此霍尔传感器已广泛应用于微机测控系统及智能仪表中,是替代互感器的新一代产品。在此提出了利用霍尔传感器对电参量特别是对高电压、大电流的参数的测量。 l测量原理 霍尔效应原理 如图2所示,一个N型半导体薄片,长度为L,宽度为S,厚度为d,在垂直于该半导体薄片平面的方向上,施加磁感应强度为B的磁场,若在长度方向通以电流Ic则运动电荷受到洛伦兹力的作用,正负电荷将分别沿垂直于磁场和电流的方向向导体两端移动,并在导体两端形成一个稳定的电动势UH,这就是霍尔电动势(或称之为霍尔电压),这种现象称为霍尔效应。霍尔电压的大小UH=RIB/d=KHICB, 其中R为霍尔常数;KH为霍尔元件的乘积灵敏度。 2用霍尔传感器测量电参量的原理 由霍尔电压公式可知:对于一个成型的霍尔传感器,乘积灵敏度KH是一恒定值,则UH?ICB,只要通过测量电路测出UH的大小,在B和IC两个参数中,已知一个,就可求出另一个,因而任何可转换成B或J的未知量均可利用霍尔元件来测量,任何转换成B和I乘积的未知量亦可进行测量。电参量的测量就是根据这一原理实现的。 若控制电流IC为常数，磁感应强度B与被测电流成正比，就可以做成霍尔电流传感器测电流，若磁感应强度B为常数，IC与被测电压成正比，可制成电压传感器测电压，利用霍尔电压、电流传感器可测交流电的功率因数、电功率和交流电的频率。 图2 由UH=KICB可知:若IC为直流，产生磁场B的电流IO为交流时，UH为交流;若IO亦为直流，则输出也为直流。当IC为交流，IO亦为直流时，输出与IC同频率的交流且其幅值与被测直流IO大小成正比，改变被测电流IO的方向，输出电压UH极性随之改变。based on datum point will be provided in units, according to construction drawings with the main axis for establishing horizontal control network of controlled axis. For effective implementation of measurement and control during the construction process, the master axis extends beyond the limits of excavation, set a permanent control points. Set up benchmarks to require stability, reliability, visibility, and TIC investment survey has been completed, checking with each other, its relative error is less than 1/30000 on a side, angle-measuring error is less than 7. " Strengthening network protection. 2. the Foundation, basement axis control: cushion construction has been completed, the master axis measured by theodolite voted on the cushion and cushion down to throw measured on the surface of the master axis is checked, error controla Red flag, as a basis for binding reinforcement and formwork. Foundations, basement finished, the master axis projection measuring on the basement to the roof, gave off the axis of the wall or the line of control (outside the axis 200mm) basis for the formwork. 3. the main structural axis control: Foundation construction has been completed, check the master axis points after a collision-free motion and displacement, the master axis projection measuring on the basement to the roof, close checking correct-by-construction drawings released axis, let out wall lines and basic axis displacement and checking each axis dimension. Each template is complete, double-check on the axis of the wall. After the floor has been poured, using theodolite vertical method, each floor is subject to axis, first floor, using extension methods or lateral borrowed 故利用霍尔传感器，既可对直流量进行测量，亦可对交流量进行测量。 3系统结构简图 检测系统构成如图3，被测量经霍尔传感器转换为电压信号，经信号调理电路和多路转换开关选择，通过A,D转换器送给单片机，单片机采用89C51，是该系统的主控器，键盘选用2×4键盘，用于选择被测量的种类，采用数码管或液晶显示被测量的大小。 图3 4电参量的测量方法 1电压、电流信号的测量 电流的测量可采用磁平衡式霍尔电流传感器(亦称为零磁通式霍尔传感器)如图4所示。 图4 当被测电流IIN流过原边回路时，在导线周围产生磁场HIN这个磁场被聚磁环，并感应给霍尔器件，使其有一个信号UH输出;这 一信号经放大器A 放大，输人到功率放大器中Q1，Q2中，这时相应的功率管导通，从而获得一个补偿电流IO;由于此电流通过多匝绕组所产生的磁场HO与原边回路电流所产生的磁场HIN相反;因而补偿了原来的磁场，使霍尔器件的输出电压UH逐渐减小，最后当IO与匝数相乘N2IO所产生的磁场与原边N1IIN所产生的磁场相等时，IO不再增加，这时霍尔器件就达到零磁通检测作用。 这一平衡所建立的时间在1μs之内，这是一个动态平衡过程，即原边回路电流IIN的任何变化均会破坏这一平衡的磁场，一旦磁场失去平衡，就有信号输出，经过放大后，立即有相应的电流流过副边线圈进行补偿。因此从宏观上看副边补偿电流的安匝数在任何时间都与原边电流的安匝数保持相等，即 N1IIN=N2IO，所以IIN=N2I2,N1(IIN为被测电流，即磁芯中初级绕组中的电流，N1为初级绕组的匝数;IO为补偿绕组中的电流;N2 为补偿绕组的匝数)。 由原、副边匝数可知，只要测得补偿线圈的电流IO，即可知道原边电流IIN，如原边为导线穿心式，则N1=l，IIN=N2IO。利用同样的原理可进行电压测量，只需在原边线圈回路中串联一个电阻R1，将原边电流IIN转换成被测电压UIN。即UIN=(R1+RIN)IIN= (R1+RIN)N2IO,N1，RIN为原边绕阻的内阻(一般很小不计)。对特高压交流电压的测量，先经隔离变压器降压后，对降压后的电压进行测量，然后对测量数据乘以倍数，即可得被测电压的大小。 该测量输出信号为电流形式IO。若在霍尔电流传感器的输出电路与电源零点之间串接恰当的电阻R0，并在该电阻上取电压，就构based on datum point will be provided in units, according to construction drawings with the main axis for establishing horizontal control network of controlled axis. For effective implementation of measurement and control during the construction process, the master axis extends beyond the limits of excavation, set a permanent control points. Set up benchmarks to require stability, reliability, visibility, and TIC investment survey has been completed, checking with each other, its relative error is less than 1/30000 on a side, angle-measuring error is less than 7. " Strengthening network protection. 2. the Foundation, basement axis control: cushion construction has been completed, the master axis measured by theodolite voted on the cushion and cushion down to throw measured on the surface of the master axis is checked, error controla Red flag, as a basis for binding reinforcement and formwork. Foundations, basement finished, the master axis projection measuring on the basement to the roof, gave off the axis of the wall or the line of control (outside the axis 200mm) basis for the formwork. 3. the main structural axis control: Foundation construction has been completed, check the master axis points after a collision-free motion and displacement, the master axis projection measuring on the basement to the roof, close checking correct-by-construction drawings released axis, let out wall lines and basic axis displacement and checking each axis dimension. Each template is complete, double-check on the axis of the wall. After the floor has been poured, using theodolite vertical method, each floor is subject to axis, first floor, using extension methods or lateral borrowed 成了电压形式的输出。输出电压经电压调整电路、线性放大电路、不等位补偿电路、射集跟随等获得所需的电压，便于测量与显示。 5功率及功率因数、频率等电参数的测量 由正弦交流电有功功率的定义P=UIcosψ可知，只要准确测量出U，I及电流与电压相位差ψ，就可算出P与cosψ。采用传统的电磁式电压、电流互感器进行测量，由于互感器的非理想性，除存在变比误差外，更主要的是存在较大的相位误差，这就使测得的ψ值不能真实地反映负载的性质。若采用霍尔电压、电流传感器及真有效值转换器(如AD637)等，可以使功率及功率因数的测量精度大大提高。 此外，霍尔传感器还可以测量从直流到100kHz的任意波形的交流量，从而克服了电磁式互感器有特定的额定频率的弊端。真有效值转换器可以将正弦波形或任意波形的交流量转换为直流量，输出直流的大小正比于交流量的有效值，且转换精度高，因而测量相对准确。 图5 测量原理如图5所示，交直流电压、电流经霍尔电流传感器、霍尔电压传感器隔离、转换后，得到与之对应的电压信号，再经真有效值转换器转换为直流(直流电不需转换)，其大小正比于交流电的有效值，直流(或转换后的直流)电压经A,D变换后送入单片机，这就采集到了U，I的大小。 另外将传感器副边输出的电信号 U1，U2分别经过零电平比较器1和2，当信号由负变正，通过零点时产生一个脉冲，加到门控电路输入端。设U1超前于U2，则前者作开启信号，后者作关闭信号。门控电路产生一个脉冲宽度对应于两个信号相位差的矩形脉冲，该脉冲一路送单片机的定时,计数器T1口，单片机测出相邻两个矩形脉冲前沿之间的时间间隔t，即为被测信号的周期Tx(频率fx=1,Tx)。 另一路送至与门电路，打开计数与门，在此期间，时标信号Ts经由与门至单片机的定时,计数器TO口计数，设计数值为N，则U1与U2相位差为 ?ψ=Ts,TxN×360?。经单片机计算出功率因数cosψ，进一步计算出有功功率P,UIcosψ，并将测得参数U，I，P，cosψ，ψx等送显示电路显示。如要测三相电路的总功率，则分别测得每一相的功率，然后三相功率相加即可。此外，该系统也可测量无功功率和视在功率等电参数。 基于霍尔传感器的电参量检测系统具有很好的线性度、精确度和良好的反应时间。温度漂移小，霍尔元件在-40,+45?的温度范围内，霍尔电压的温度系数仅为0(03,,O(04,。 这里所介绍的测量方法达到了对电参量进行高精度的隔离传输based on datum point will be provided in units, according to construction drawings with the main axis for establishing horizontal control network of controlled axis. For effective implementation of measurement and control during the construction process, the master axis extends beyond the limits of excavation, set a permanent control points. Set up benchmarks to require stability, reliability, visibility, and TIC investment survey has been completed, checking with each other, its relative error is less than 1/30000 on a side, angle-measuring error is less than 7. " Strengthening network protection. 2. the Foundation, basement axis control: cushion construction has been completed, the master axis measured by theodolite voted on the cushion and cushion down to throw measured on the surface of the master axis is checked, error controla Red flag, as a basis for binding reinforcement and formwork. Foundations, basement finished, the master axis projection measuring on the basement to the roof, gave off the axis of the wall or the line of control (outside the axis 200mm) basis for the formwork. 3. the main structural axis control: Foundation construction has been completed, check the master axis points after a collision-free motion and displacement, the master axis projection measuring on the basement to the roof, close checking correct-by-construction drawings released axis, let out wall lines and basic axis displacement and checking each axis dimension. Each template is complete, double-check on the axis of the wall. After the floor has been poured, using theodolite vertical method, each floor is subject to axis, first floor, using extension methods or lateral borrowed 和精确检测的目的，特别适合高电压、大电流电参量的测量。这为研制一种新的电参量测量仪器打下了一个良好的基础，在上具有一定的应用价值。不足之处，霍尔元件存在不等位的电势的影响，需加补偿电路修正。 参考文献 [1] 周杏鹏.现代检测技术.高等教育出版社，2010 [2] 郁有文.传感器原理及工程应用.西安电子科技大学出版社，2008 [3] 张三慧.大学物理学.清华大学出版社，2010 based on datum point will be provided in units, according to construction drawings with the main axis for establishing horizontal control network of controlled axis. For effective implementation of measurement and control during the construction process, the master axis extends beyond the limits of excavation, set a permanent control points. Set up benchmarks to require stability, reliability, visibility, and TIC investment survey has been completed, checking with each other, its relative error is less than 1/30000 on a side, angle-measuring error is less than 7. " Strengthening network protection. 2. the Foundation, basement axis control: cushion construction has been completed, the master axis measured by theodolite voted on the cushion and cushion down to throw measured on the surface of the master axis is checked, error controla Red flag, as a basis for binding reinforcement and formwork. Foundations, basement finished, the master axis projection measuring on the basement to the roof, gave off the axis of the wall or the line of control (outside the axis 200mm) basis for the formwork. 3. the main structural axis control: Foundation construction has been completed, check the master axis points after a collision-free motion and displacement, the master axis projection measuring on the basement to the roof, close checking correct-by-construction drawings released axis, let out wall lines and basic axis displacement and checking each axis dimension. Each template is complete, double-check on the axis of the wall. After the floor has been poured, using theodolite vertical method, each floor is subject to axis, first floor, using extension methods or lateral borrowed