高精度闭环可分磁芯式霍尔电流传感器

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3.0 牛悦 2024-11-11 4 4 1.23MB 57 页 15积分
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摘要
随着新能源技术的快速发展,太阳能、风能和电动汽车等领域对电流跟踪测
量和监视的要求也随之提高。霍尔电流传感器正是在此基础上诞生的一种性能优
越的电流测量仪器。目前工业中使用的霍尔电流传感器,基本可分为开环和闭环
两种结构,它们都由一个环形的磁芯和霍尔芯片构成。传统的开启式电流传感器
普遍采用开环原理,但这种结构有如下缺点,低精度、结果稳定性欠佳、较高的
温漂和窄的频率适用范围闭环电流传感器有更好的输出特性,但缺点是不易
安装。
基于此种现状,本文设计了一种新型结构的开启式闭环霍尔电流传感器,可
在保持闭环特性的条件下,使其同时具有方便开启的功能文中分析了霍尔电流
传感器闭环结构的数学模型,进行磁场模型分析,并通过实验验证了不同形状的
磁芯对传感器产生的影响,证明了了这种设计的可行性整个系统由聚磁磁芯、
磁性空隙中的霍尔芯片、次级电流反馈电路、霍尔芯片恒流源、电压放大电路、
次级线圈、信号补偿调节电路、恒压电源等部分组成。因霍尔芯片和放大电路都
是线性输出,故传感器的输出也随电流的输入而线性变化。
经过大量的实结果分析文中一步提出了提高传感器精度和稳定性的改
进方法,设计了一个信号调节控制电路来增强开启式电流传感器的性能。通过实
验数据可知,这种结构的传感器只是增加了较低的花费,就使得产品的线性度和
精准度大大提高。
结果证明这种新型结构的开启式闭环霍尔电流传感器具有较宽的测量范围且
在整个范围内都有良好的精度,反应时间短,具有极佳的线性度,采用的非接
式原理也减少了能源消耗,并且提高了操作人员的工作安全性。由此可见,这种
易于安装的电流传感器必将广泛用于能源行业。
关键词: 闭环开启式 霍尔电流传感器 高精度
ABSTRACT
With high speed development of new energy industry, the demands of
measuring and monitoring technologies of solar, wind energy and electronic automobile
have been raised. Current sensors become widely used in this kind of situation because
of high performance. For the hall effect current sensors, there are two basic measuring
methods, open loop and closed loop principle. Both kinds of sensors use a magnetic
core with air gap, where a hall effect device is inserted. And the traditional split core
current sensors normally choose the open loop structure. However the open loop sensors
have the disadvantages of lower accuracy and stability, higher thermal drift and narrow
frequency range. On the other hand, the closed loop sensors with solid core have better
output performances but not easy to install.
Considering about this situation, in this paper, a new structure split core closed
loop hall effect current sensor has been designed. Through the principle analysis of
closed loop mathematical model and magnetic field simulation, and compared with the
different shapes of soft magnetic cores, a basic split core closed loop current sensor has
been measured. With the adjusting coil turns experiments, the output of sensor could be
in the available range. In order to improve the accuracy and stability of sensors, a signal
conditioning circuitry is designed to advance the performance of split core current
sensor with two adjustment parts. With the experiment results, the linearity and
accuracy of sensor is better than the former one. This structure sensor becomes the high
precision instrument with low additional costs.
In order to improve the accuracy and stability of sensors, a signal conditioning
circuitry is designed to advance the performance of split core current sensor with two
adjustment parts. With the experiment results, the linearity and accuracy of sensor is
better than the former one. This structure sensor becomes the high precision instrument
with low additional costs.
Depending on the measurement results, the new structure split core closed loop
hall effect current sensor is proved having the advantages of wide measuring range,
good overall accuracy, fast response time, excellent linearity and no insertion losses. As
the sensor is convenient to be mounted in energy system cause its open structure, it will
have a wide usage future.
Key Word: Closed loop, Split core, Hall Effect current sensor
Contents
Chapter 1 - Introduction................................................................................................... 1
1.1 Photovoltaic cell ................................................................................................. 1
1.2 Photovoltaic system and measurement equipment ............................................. 2
1.3 Methods of Current measurement ...................................................................... 4
1.4 Main work of thesis ............................................................................................ 6
Chapter 2 - Current sensor principle and analysis ........................................................... 7
2. 1 Hall Effect current sensor ................................................................................... 7
2.1.1 Open-Loop principle ................................................................................. 7
2.1.2 Closed-Loop principle ............................................................................... 9
2.1.3 Open and closed-loop compared ........................................................... 10
2.2 Closed Loop Mathematical model and analysis ............................................... 12
2.2.1 Closed Loop Mathematical model........................................................... 12
2.2.2 The mathematic analysis of closed loop current sensor. ......................... 14
2.2.3 Inhibition of high frequency noise for closed loop current sensor .......... 15
2.3 Main parameters of closed loop sensor ............................................................. 16
2.4 Characteristics of soft magnetic core............................................................... 18
2.5 Calculate the linearity and accuracy approach .................................................. 19
2.5.1 Least squares method .............................................................................. 19
2.5.2 Calculation of the measurement accuracy ............................................... 20
2.6 Magnetic field analysis ...................................................................................... 20
Chapter 3 - Design the hardware parts .......................................................................... 22
3.1 Block diagram.................................................................................................... 22
3.2 Power supply ..................................................................................................... 23
3.3 Hall effect device .............................................................................................. 25
3.3.1 Introduction to the hall effect .................................................................. 25
3.3.2 Structure and principle operation ............................................................ 26
3.3.3 Hall device characters.............................................................................. 26
3.4 Amplifier............................................................................................................ 27
3.4.1 Introduction of op-amp ............................................................................ 27
3.4.2 Differential Amplifier.............................................................................. 29
3.5 Protection circuit................................................................................................ 30
Chapter 4 - Experiments and results .............................................................................. 32
4.1 Compare the solid and split core ....................................................................... 32
4.2 The Choice of split core..................................................................................... 33
4.3 Coil position experiment.................................................................................... 36
4.4 Compensation experiments................................................................................ 38
Chapter 5 - Improving methods ..................................................................................... 41
5.1 New compensation circuit structure .................................................................. 41
5.2 Offset adjustment ............................................................................................... 42
5.3 Gain Adjustment ................................................................................................ 43
5.4 Experiment Results ............................................................................................ 45
Chapter 6 - Conclusions................................................................................................. 47
6.1 Applications ....................................................................................................... 47
6.2 Summary ........................................................................................................... 47
6.3 Future work........................................................................................................ 48
Reference .......................................................................................................................... 50
The published paper and project achievements in study period ....................................... 53
Acknowledgements........................................................................................................... 54
1. Introduction
1
Chapter 1 - Introduction
1.1 Photovoltaic cell
A photovoltaic cell is a system which includes one or more solar panels. It
works to convert sunlight into electricity. It consists of numerous components, such as
photovoltaic modules, electrical, mechanical connections and some parts to regulate and
modify the electrical output[1].
Photovoltaic array is assembled by PV modules. The solar panels at some places
where opulent with direct sunshine can charge the 12 volt batteries at up to 9 amperes in
full. A photovoltaic array is also linked collection of solar panels.
Fig 1.1 Photovoltaic cell
The power produced by one module is few enough to meet the requirement of a
house or a corporation, so the modules should be connected together to form an array.
Inverter could be used in most PV arrays for converting the DC power that produced by
the modules into AC current which can provide the power to lights, motors, and other
loads. The modules in a PV array are linked in series to receive the rated voltage,
meanwhile, the individual strings are connected in parallel would help the system to
produce more power.
摘要:

摘要随着新能源技术的快速发展,太阳能、风能和电动汽车等领域对电流跟踪测量和监视的要求也随之提高。霍尔电流传感器正是在此基础上诞生的一种性能优越的电流测量仪器。目前工业中使用的霍尔电流传感器,基本可分为开环和闭环两种结构,它们都由一个环形的磁芯和霍尔芯片构成。传统的开启式电流传感器普遍采用开环原理,但这种结构有如下缺点,低精度、结果稳定性欠佳、较高的温漂和窄的频率适用范围。闭环式电流传感器有更好的输出特性,但缺点是不易安装。基于此种现状,本文设计了一种新型结构的开启式闭环霍尔电流传感器,可在保持闭环特性的条件下,使其同时具有方便开启的功能。文中分析了霍尔电流传感器闭环结构的数学模型,进行磁场模型...

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作者:牛悦 分类:高等教育资料 价格:15积分 属性:57 页 大小:1.23MB 格式:PDF 时间:2024-11-11

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