CN105891757B - Open-loop Hall sensor measurement accuracy calibration device and calibration method thereof - Google Patents
Open-loop Hall sensor measurement accuracy calibration device and calibration method thereof Download PDFInfo
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- 238000012795 verification Methods 0.000 claims description 11
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- 239000006185 dispersion Substances 0.000 claims description 6
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Abstract
The invention provides a calibration device for measuring accuracy of an open-loop Hall sensor, which comprises: the output end of the power supply is connected with a current lead uniformly wound on the open-loop Hall sensor through a power switch and used for providing test current for the open-loop Hall sensor; the loop current detection device is connected in series with an output loop of the power supply and is used for detecting the loop current output by the power supply; and the matched detection device is respectively connected with the output end of the open-loop Hall sensor and the control end of the power switch and is used for acquiring the output data of the open-loop Hall sensor and controlling the power switch to be switched on or off according to the output data and the loop current detected by the loop current detection device. The scheme provided by the invention can reach the performance index of the closed-loop technology Hall by using the relatively cheap open-loop Hall sensor, and provides a good reference for high-precision measurement of the open-loop Hall sensor.
Description
Technical Field
The invention relates to a calibration device and a calibration method, in particular to a calibration device and a calibration method for the measurement accuracy of an open-loop Hall sensor.
Background
In high current testing of dc systems, it is common to use dc shunts and hall sensors to measure current. The precision of the direct current divider is relatively high, and is generally 0.5-0.2 grade; the direct current shunt is connected in series in the primary loop, the power consumption is large (for example, 1000A, 75mV, power consumption of 75W), and the measurement is not isolated from the secondary loop. The hall technology is the most common method in recent years for measuring the large current of a direct current system, wherein the hall sensor of the closed-loop technology can reach the technical level of 0.5 grade. However, the hall sensor of the closed-loop technology has a relatively large volume, is provided with a coil, needs an external excitation power supply, has no opening, and can be installed and debugged only once along with a measured current loop.
The open-loop Hall sensor is composed of an iron core with an open magnetic gap, a Hall element clamped at the open and a whole sealing body, and has large difference of physical dimensions due to different measuring current ranges, but the basic physical structure and principle are the same. Compared with a Hall sensor in a closed-loop technology, the Hall sensor in the open-loop technology is small in size, does not need high-power supply excitation, and can be particularly made into a structure with an iron core opening (such as a direct-current clamp meter) to facilitate field measurement. But one serious disadvantage is that the measurement accuracy is low, and the common measurement error is 3% -5%. The best measurement accuracy on the market is only about 1.5%.
The current situation is as follows: in the past, direct current does not need to be measured with high precision in general, but with the large investment of new energy inverter equipment such as micro grids and energy storage, direct current needs to be measured with high precision. For example, in a high-power energy storage and inversion power device, the measurement of the conversion efficiency requires the measurement of the dc current with high precision and the calculation of the total dc power. As a third party for detecting and evaluating the equipment, a direct current sensor is required to be externally connected to measure the current. The closed-loop hall sensor is inherently good, but installation under field conditions is too complicated. Therefore, if the open-loop hall sensor with iron core opening can be measured accurately, it would be very practical to increase the measurement accuracy to an acceptable level by some method.
Disclosure of Invention
In order to solve the defects in the prior art, the invention provides the calibration device and the calibration method for the measurement readiness of the Hall sensor.
The technical scheme provided by the invention is as follows: the utility model provides a calibration equipment of open loop hall sensor measurement accuracy which improves and lies in: the device comprises:
the output end of the power supply is connected with a current lead uniformly wound on the open-loop Hall sensor through a power switch and used for providing test current for the open-loop Hall sensor;
the loop current detection device is connected in series with an output loop of the power supply and is used for detecting the loop current output by the power supply;
and the matched detection device is respectively connected with the output end of the open-loop Hall sensor and the control end of the power switch and is used for acquiring the output data of the open-loop Hall sensor and controlling the power switch to be switched on or off according to the output data and the loop current detected by the loop current detection device.
Preferably, the power supply is a power storage battery with no high-frequency ripple content in the output current.
Preferably, the power switch comprises parallel MOS transistors, after the MOS transistors are connected in parallel, a drain electrode of the MOS transistor is connected with one end of the current conducting wire, a source electrode of the MOS transistor is connected with an output end of the power supply, and a gate electrode of the MOS transistor is connected with the matched detection device.
Preferably, the loop current detection device includes a shunt and a digital mV meter, the shunt is connected in series to the output loop of the power supply, and is connected to the digital mV meter, so as to convert a large current on the output loop into a small current for the digital mV meter to measure.
Preferably, supporting detection device includes power analyzer and detection frock, power analyzer's input with open loop hall sensor's output links to each other, its output with the input that detects the frock links to each other, is used for gathering open loop hall sensor's output data to give the data transmission who gathers the detection frock, it reads to detect the frock open loop hall sensor's that power analyzer gathered output data and the return circuit current that return circuit current detection device detected, and according to open loop hall sensor's output data and return circuit current control power switch's the disconnection.
Further, the detection tool calculates linear functions of the open-loop hall sensor in different measurement sections according to the output data of the open-loop hall sensor and the loop current, linear coefficients of the linear functions in the different measurement sections are transmitted to the power analyzer after the calculation of the detection tool is completed, and the linear coefficients are stored by the power analyzer.
Another object of the present invention is to provide a calibration method implemented by an open-loop hall sensor measurement accuracy calibration apparatus, the method comprising:
1) measuring output data of the open-loop Hall sensor when the loop current detected by the loop current detection device is zero;
2) adjusting a loop resistance, and estimating a loop current according to the loop resistance to ensure that the loop current does not exceed the maximum allowable current of the open-loop Hall sensor and ensure that the loop current does not exceed the short-time limit current of a power supply;
3) controlling the short-time conduction of an MOS tube, reading output data of an open-loop Hall sensor when the MOS tube is conducted and standard loop current measured by a loop current detection device, and closing the MOS tube after the dispersion point is determined;
4) changing the polarity of the current flowing through the open-loop Hall sensor or changing the loop resistance, and repeating the step 3);
5) obtaining linear equations of different sections according to all the determined scatter points;
6) and calculating and calibrating an actual current value corresponding to the output data of the open-loop Hall sensor through linear interpolation according to linear equations of different sections.
Further, the standard loop current measured by the loop current detection device in the step 3) is manually input into the detection tool.
Preferably, the scattered point in the step 3) is a parameter coordinate point formed by a standard loop current value and a corresponding open-loop hall sensor sampling value.
Preferably, in the step 4), the loop resistance is changed by changing the number of turns of the winding wound on the open-loop hall sensor or connecting power resistors with different resistances in series.
Compared with the closest prior art, the invention has the following remarkable progress:
1, the defect of sensor output data distortion caused by vibration and other human factors of the Hall sensor with the fine-tuning potentiometer is eliminated.
And 2, uniformly winding a current wire on the open-loop Hall sensor, and simulating a large current of nearly kiloamperes of the energy storage equipment by adopting a small current controlled by an electronic switch to realize the verification and measurement under a controllable real current scene.
3, directly from the source value to the target value, the dispersion error of the open-loop Hall sensor caused by the manufacturing process is eliminated; and the dispersion error of the internal reference standard of the matched detection equipment is eliminated.
4, the measuring effect which can be achieved by a relatively expensive closed-loop Hall can be achieved by using a cheap open-loop Hall sensor.
5, the open-loop Hall sensor adopts an open iron core, so that the installation is convenient; the voltage quantity is output, and the capacity requirement of the power supply can be greatly reduced.
Drawings
Fig. 1 is a schematic structural diagram of an open-loop hall sensor calibration apparatus provided by the present invention.
Detailed Description
The following describes embodiments of the present invention in further detail with reference to the accompanying drawings.
In the following description, a detailed structure will be presented for a thorough understanding of embodiments of the invention. It is apparent that the implementation of the embodiments of the present invention is not limited to the specific details familiar to those skilled in the art. The following detailed description of the preferred embodiments of the invention, however, the invention is capable of other embodiments in addition to those detailed.
The invention provides a calibration device for measuring accuracy of an open-loop Hall sensor, which has a structure shown in figure 1: the device comprises:
the output end of the power supply is connected with a current lead uniformly wound on the open-loop Hall sensor through a power switch and used for providing test current for the open-loop Hall sensor;
the loop current detection device is connected in series with an output loop of the power supply and is used for detecting the loop current output by the power supply;
and the matched detection device is respectively connected with the output end of the open-loop Hall sensor and the control end of the power switch and is used for acquiring the output data of the open-loop Hall sensor and controlling the power switch to be switched on or off according to the output data and the loop current detected by the loop current detection device.
The power supply is a power storage battery without high-frequency pulsation content in output current of the power supply.
The current lead is a low-resistance lead, and when the low-resistance lead is uniformly wound on the calibrated open-loop Hall sensor for 10 circles, the actual current of the calibrated Hall sensor is 10 times of the current of the power supply output loop.
The power switch comprises MOS tubes connected in parallel, and the total resistance of the loop is required to be less than 0.2 ohm in order to enable the loop current to reach a desired range; in fig. 1, three high-power MOS transistors (Q1, Q2, Q3) are used in parallel, also to reduce the on-resistance. And after the MOS tubes are connected in parallel, the drain electrode of each MOS tube is connected with one end of the current lead, the source electrode of each MOS tube is connected with one output end of the power supply, and the grid electrode of each MOS tube is connected with the matched detection device.
The loop current detection device comprises a shunt and a digital mV meter, wherein the shunt is connected in series with an output loop of the power supply and is connected with the digital mV meter, and is used for converting large current on the output loop into small current to be measured by the digital mV meter. The shunt is a high-precision direct current shunt, and the digital mV meter is a high-precision digital mV meter. For example: an 500/75mV, 0.1 fraction flow divider was used; and configuring a digital mV table with 0.05-level precision.
The matched detection device comprises a power analyzer and a detection tool, wherein the input end of the power analyzer is connected with the output end of the open-loop Hall sensor, the output end of the power analyzer is connected with the input end of the detection tool and used for collecting the output data of the open-loop Hall sensor, the collected data are transmitted to the detection tool, the detection tool reads the output data of the open-loop Hall sensor collected by the power analyzer and the loop current detected by the loop current detection device, and the detection tool controls the on-off of the power switch according to the output data of the open-loop Hall sensor and the loop current.
The detection tool also calculates linear functions of the open-loop Hall sensor in different measurement sections according to the output data of the open-loop Hall sensor and the loop current, and linear coefficients of the linear functions in the different measurement sections are transmitted to the power analyzer after being calculated by the detection tool and are stored by the power analyzer.
The method comprises the steps of determining scattering points through a plurality of groups of standard loop current values measured by a high-precision digital mV (mV) meter and collected current values of the open-loop Hall sensor, determining linear functions of different measurement sections according to the scattering points, and calibrating a sampling value of the open-loop Hall sensor under typical current. The open-loop Hall sensor corresponding to the sampling value under the typical current is calculated according to the scattered point, and the function of the sampling value in the verification process is as follows: standard coefficients that the program can recognize are formed. The actual measurement of a plurality of groups of current sampling scattered points, for example, two points of which are 36A and 103A, is to calculate what the number of the sampling values of the open-loop hall sensor is when the corresponding standard loop current is 100A, which is a calculation way for simplifying the internal calculation for the convenience of a matched detection device. The matched detection device only stores the calculation sampling values corresponding to the standard loop currents of 100A, 200A, 300A-500A. In application, linear equations of different intervals are formed, the current interval is determined according to the sampling values, and the real current corresponding to the output data of the open-loop Hall sensor is calculated by executing the different linear equations.
The invention also provides a calibration method realized by using the open-loop Hall sensor measurement accuracy calibration device, which comprises the following steps:
1) measuring output data of the open-loop Hall sensor when the loop current detected by the loop current detection device is zero;
2) adjusting a loop resistance, and estimating a loop current according to the loop resistance to ensure that the loop current does not exceed the maximum allowable current of the open-loop Hall sensor and ensure that the loop current does not exceed the short-time limit current of a power supply;
the on-resistance of the power MOS tube can be inquired about a related data manual, the wire resistance is measured by a double-arm bridge or a micro-ohm meter, and the wire resistance and the on-resistance of the MOS tube form a loop resistance. The loop current value is estimated from the loop resistance and the battery.
3) Controlling the short-time conduction of an MOS tube, reading output data of an open-loop Hall sensor when the MOS tube is conducted and standard loop current measured by a loop current detection device, and closing the MOS tube after the dispersion point is determined; the conduction time of the MOS tube is generally 3-5 seconds;
4) changing the polarity of the current flowing through the open-loop Hall sensor or changing the loop resistance, and repeating the step 3) until the determined scatter points reach the quantity and the size required by the test;
5) obtaining linear equations of different sections according to all the determined scatter points;
6) and calculating and calibrating an actual current value corresponding to the output data of the open-loop Hall sensor through linear interpolation according to linear equations of different sections.
And (3) manually inputting the standard loop current measured by the loop current detection device in the step 3) into the detection tool. The current real-time current measurement standard value can be input in a communication mode after improvement, and the input aims to enable the detection tool to obtain the current real-time current measurement standard value (the current reference true value).
The scattered point in the step 3) refers to a parameter coordinate point formed by a standard loop current value measured by a digital mV (mV) meter corresponding to a certain current and an open-loop Hall sensor sampling value in the current measuring process. Such multiple "scatter points" may constitute linear equations for different segments. The method can be used for carrying out linear interpolation calculation to determine the actual current value corresponding to the output data of the open-loop Hall sensor, and calibrating the output data of the open-loop Hall sensor and the actual current value one by one.
And in the step 4), the loop resistance is changed by changing the number of turns of the winding wound on the open-loop Hall sensor or connecting the power resistors with different resistances in series.
The actual measurement shows that the open-loop Hall sensor with 3 percent of error (dispersion error) can be calibrated to achieve the measurement accuracy of 0.5 percent (at the ambient temperature of 5-25 percent) by the method and the device.
Finally, it should be noted that: although the present invention has been described in detail with reference to the above embodiments, those skilled in the art can make modifications and equivalents to the specific embodiments of the invention without departing from the spirit and scope of the invention, which is set forth in the claims appended hereto.
Claims (9)
1. A method for verifying the measurement accuracy of an open-loop Hall sensor is characterized by comprising the following steps: the open-loop Hall sensor measuring accuracy verifying device comprises:
the output end of the power supply is connected with a current lead uniformly wound on the open-loop Hall sensor through a power switch and used for providing test current for the open-loop Hall sensor;
the loop current detection device is connected in series with an output loop of the power supply and is used for detecting the loop current output by the power supply;
the matched detection device is respectively connected with the output end of the open-loop Hall sensor and the control end of the power switch and is used for acquiring the output data of the open-loop Hall sensor and controlling the power switch to be switched on or off according to the output data and the loop current detected by the loop current detection device;
the verification method comprises the following steps:
1) measuring output data of the open-loop Hall sensor when the loop current detected by the loop current detection device is zero;
2) adjusting a loop resistance, and estimating a loop current according to the loop resistance to ensure that the loop current does not exceed the maximum allowable current of the open-loop Hall sensor and ensure that the loop current does not exceed the short-time limit current of a power supply;
3) controlling the short-time conduction of an MOS tube, reading output data of an open-loop Hall sensor when the MOS tube is conducted and standard loop current measured by a loop current detection device, and closing the MOS tube after the dispersion point is determined;
4) changing the polarity of the current flowing through the open-loop Hall sensor or changing the loop resistance, and repeating the step 3);
5) obtaining linear equations of different sections according to all the determined scatter points;
6) and calculating and calibrating an actual current value corresponding to the output data of the open-loop Hall sensor through linear interpolation according to linear equations of different sections.
2. The open-loop Hall sensor measurement accuracy verification method according to claim 1, wherein:
the power supply is a power storage battery without high-frequency pulsation content in output current of the power supply.
3. The open-loop Hall sensor measurement accuracy verification method according to claim 1, wherein:
the power switch comprises MOS tubes connected in parallel, the drain electrodes of the MOS tubes are connected with one end of the current lead after the MOS tubes are connected in parallel, the source electrodes of the MOS tubes are connected with one output end of the power supply, and the grid electrodes of the MOS tubes are connected with the matched detection device.
4. The open-loop Hall sensor measurement accuracy verification method according to claim 1, wherein:
the loop current detection device comprises a shunt and a digital mV meter, wherein the shunt is connected in series with an output loop of the power supply and is connected with the digital mV meter, and is used for converting large current on the output loop into small current to be measured by the digital mV meter.
5. The open-loop Hall sensor measurement accuracy verification method according to claim 1, wherein:
the matched detection device comprises a power analyzer and a detection tool, wherein the input end of the power analyzer is connected with the output end of the open-loop Hall sensor, the output end of the power analyzer is connected with the input end of the detection tool and used for collecting the output data of the open-loop Hall sensor, the collected data are transmitted to the detection tool, the detection tool reads the output data of the open-loop Hall sensor collected by the power analyzer and the loop current detected by the loop current detection device, and the detection tool controls the on-off of the power switch according to the output data of the open-loop Hall sensor and the loop current.
6. The open-loop Hall sensor measurement accuracy verification method according to claim 5, wherein:
the detection tool also calculates linear functions of the open-loop Hall sensor in different measurement sections according to the output data of the open-loop Hall sensor and the loop current, and linear coefficients of the linear functions in the different measurement sections are transmitted to the power analyzer after being calculated by the detection tool and are stored by the power analyzer.
7. The verification method according to claim 1, wherein:
and (3) manually inputting the standard loop current measured by the loop current detection device in the step 3) into the detection tool.
8. The verification method according to claim 1, wherein:
the scattered point in the step 3) is a parameter coordinate point formed by the current value of the standard loop and the sampling value of the corresponding open-loop Hall sensor.
9. The verification method according to claim 1, wherein:
and in the step 4), the loop resistance is changed by changing the number of turns of the winding wound on the open-loop Hall sensor or connecting the power resistors with different resistances in series.
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| CN108205077A (en) * | 2016-12-16 | 2018-06-26 | 联合汽车电子有限公司 | Current sensing means, current detecting system and electric current detecting method |
| CN107462856B (en) * | 2017-08-09 | 2019-10-08 | 科华恒盛股份有限公司 | A kind of judgment method of alternating current detection unit failure |
| CN108631635A (en) * | 2018-03-12 | 2018-10-09 | 江苏固德威电源科技股份有限公司 | Power electronic devices and use its single-phase converter, 3-phase power converter |
| CN109870487B (en) * | 2019-02-18 | 2021-06-22 | 中国石油天然气集团有限公司 | Method, device and system for compensating resistance of conductivity sensor verification lead |
| CN109975590A (en) * | 2019-05-13 | 2019-07-05 | 江苏原容新能源科技有限公司 | Current measurement circuit based on Hall chip and shunt resistance |
| CN113124897B (en) * | 2019-12-31 | 2024-04-09 | 中信科智联科技有限公司 | Sensor performance detection method, device and terminal |
| CN112033575B (en) * | 2020-06-29 | 2022-04-08 | 国网四川省电力公司电力科学研究院 | On-site calibration method and device for on-line monitoring system of power valve control storage battery pack |
| CN113572510B (en) * | 2021-03-05 | 2022-10-28 | 华北水利水电大学 | Holographic IRS surface and communication system based on open-loop Hall sensor |
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| US7289924B2 (en) * | 2005-07-20 | 2007-10-30 | Honeywell International Inc. | Self-calibrating sensor |
| BG66361B1 (en) * | 2009-03-18 | 2013-09-30 | Institout Po Oupravlenie I Sistemni Izsledvaniya PИНСТИТУТ ПО УПРАВЛЕНИЕ И СИСТЕМНИ ИЗСЛЕДri Ban ВАНИЯ ПРИ БАН | Method for calibration of hall sensors |
| CN101718852B (en) * | 2009-12-04 | 2012-01-04 | 中国电力科学研究院 | Online detection and calibration method for Hall current sensor |
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