A zero adjustment system for Hall current sensor

Abstract

The present application relates to a zeroing system for a Hall current sensor, which includes a sampling module, a signal processing module, a processing control module, a compensation module and a power supply module; the sampling module is used to sample the output voltage of the Hall current sensor in real time after the Hall current sensor is powered on, so as to output a sampling signal; the signal processing module is used to process the sampling signal, so as to output an identification signal; the processing control module is used to output a compensation signal when the voltage value reflected by the sampling signal is not equal to the preset standard value; the compensation module is used to apply an adjustable compensation voltage to the Hall current sensor when receiving the compensation signal, so that the voltage value reflected by the current sampling signal is zero; the processing control module is also used to calculate the resistance value of the compensation resistor configured on the Hall current sensor according to the output voltage and the compensation voltage, so as to output a resistance detection signal; the power supply module is used to provide a variety of voltages. The present application can alleviate the degree of zero drift of the Hall current sensor.

Description

Technical Field

[0001] The present application relates to the field of Hall current sensors, and in particular to a Hall current sensor zeroing system. Background Art

[0002] The Hall current sensor is a sensor based on the Hall effect. Due to its advantages such as high accuracy, wide bandwidth, wide measurement range, low cost and low power consumption, the Hall sensor is widely used in the industrial field.

[0003] Generally, the Hall current sensor needs to be zeroed before leaving the factory to reduce the degree of zero drift. Specifically, a compensation resistor is configured on the Hall current sensor. In the related art, the compensation resistor is a sliding rheostat, and the staff needs to adjust the sliding rheostat so that the output of the Hall current sensor is less than zero when it is not in operation. Then, the compensation resistor is also connected to an auxiliary calibration circuit. By cooperating with the auxiliary calibration circuit, the zero drift problem can be further improved.

[0004] However, the above-mentioned compensation resistor is combined with the auxiliary calibration circuit to achieve zero adjustment, which is relatively complicated. Summary of the invention

[0005] In order to more easily improve the zero drift problem through a compensation resistor, the present application provides a Hall current sensor zero adjustment system.

[0006] The present application provides a Hall current sensor zeroing system that adopts the following technical solution:

[0007] A Hall current sensor zeroing system comprises a sampling module, a signal processing module, a processing control module, a compensation module and a power supply module;

[0008] The sampling module is used to sample the output voltage of the Hall current sensor in real time after the Hall current sensor is powered on, so as to output a sampling signal;

[0009] The signal processing module is connected to the sampling module and is used to process the sampled signal to output an identification signal within an identifiable range;

[0010] The processing control module is connected to the signal processing module, and is used to calculate the voltage value reflected by the sampling signal according to the identification signal, and output a compensation signal when the voltage value reflected by the sampling signal is not zero;

[0011] The compensation module is connected to the processing control module and is used to apply an adjustable compensation voltage to the Hall current sensor when receiving the compensation signal, so that the voltage value reflected by the current sampling signal is zero;

[0012] The processing control module is also used to calculate the resistance value of the compensation resistor configured on the Hall current sensor according to the output voltage and the compensation voltage, so as to output a resistance detection signal;

[0013] The power supply module is respectively connected to the sampling module, the signal processing module, the processing control module and the compensation module, and is connected to the mains to provide a variety of voltages.

[0014] By adopting the above technical solution, the processing control module can calculate the voltage value reflected by the current sampling signal, and can determine whether the current Hall current sensor has a zero-point offset. When the zero point of the Hall current sensor is offset, the processing control module can control the compensation module to start, so as to apply a compensation voltage to the Hall current sensor for zero adjustment. When the Hall current sensor completes the zero adjustment, the processing control module can calculate the resistance of the compensation resistor based on the output voltage and the compensation voltage, so that the staff can weld a fixed resistor of this resistance to the current Hall current sensor, thereby improving the zero-point drift problem of the Hall current sensor. Compared with related technologies, there is no need to compensate through an auxiliary calibration circuit, which is more convenient.

[0015] Optionally, the processing control module includes an amplifier and an in-phase adder;

[0016] The amplifier is used to amplify the sampling signal;

[0017] The in-phase adder is connected to the amplifier and is used for adding the voltage value reflected by the amplified sampling signal to a preset standard value to output an identification signal within an identifiable range.

[0018] By adopting the above technical solution, since the voltage value reflected by the sampling signal is positive or negative, the range of values ​​that the processing control module can read is limited, so the sampling signal needs to be amplified and superimposed with the preset standard value so that the processing control module can read it.

[0019] Optionally, the amplifier is a 2x amplifier.

[0020] By adopting the above technical solution, the amplifier amplification factor depends on the readable value range of the processing control module. A smaller amplification factor will make the processing control module unable to read, and a larger amplification factor will make the processing control module incompletely read.

[0021] Optionally, the compensation module includes a first relay and a compensation power supply;

[0022] The first relay is connected to the processing control module and is used to close when receiving the compensation signal to output a trigger signal;

[0023] The compensation power supply is connected to the first relay and the Hall current sensor respectively, and is used to provide a compensation voltage for the Hall current sensor when receiving the trigger signal.

[0024] By adopting the above technical solution, the first relay can be controlled by the processing control module to be closed or opened, thereby controlling the compensation power supply to provide a compensation voltage to the Hall sensor when the Hall sensor needs compensation.

[0025] Optionally, the processing module is connected to a display module, and the display module is used to receive the resistance detection signal and to display the resistance of the compensation resistor.

[0026] By adopting the above technical solution, it is convenient for the staff to know the resistance value of the compensation resistor.

[0027] Optionally, the processing control module is an MCU.

[0028] Optionally, the in-phase adder and the 2x amplifier as well as the first relay and the processing control module are all connected via an isolation module.

[0029] By adopting the above technical solution, the isolation module can protect the system safety and avoid mutual interference between modules with different voltages.

[0030] Optionally, the sampling module includes a second relay and two sampling resistors, the two sampling resistors are connected in series, the second relay is connected in parallel with one of the sampling resistors, and the processing control module is connected to the second relay and is also used to control the second relay to close or open.

[0031] By adopting the above technical solution, the processing control unit can control the second relay to close or open to test the linearity of the Hall current sensor.

[0032] Optionally, the power supply module includes a first level conversion unit, a second level conversion unit and a third level conversion unit;

[0033] The first level conversion unit is connected to the mains power supply and is used to change the mains power voltage to output a first amplitude voltage;

[0034] The second level conversion unit is connected to the first level conversion unit, connected to the first amplitude voltage, and is used to change the first amplitude voltage to output a second amplitude voltage;

[0035] The third level conversion unit is connected to the first level conversion unit, receives the first amplitude voltage, and is used to change the first amplitude voltage to output a third amplitude voltage.

[0036] In summary, the present application includes at least one of the following beneficial technical effects:

[0037] 1. The processing control module can determine whether the zero point of the Hall current sensor has drifted based on the voltage collected by the sampling module. When the zero point of the Hall current sensor drifts, the processing control module can control the compensation module to apply a compensation voltage to the Hall current sensor for compensation, and then measure the resistance value of the compensation resistor, so that the staff can configure a resistor with a corresponding resistance value for the Hall current sensor to improve the zero point drift problem of the Hall current sensor;

[0038] 2. By setting an amplifier and a common-mode adder, the voltage value reflected by the sampling signal can be changed, so that the processing control module can read the voltage value reflected by the sampling signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 Schematic diagram of the zeroing system of the Hall current sensor according to the embodiment of the present application.

[0040] Figure 2 It is a schematic diagram of the principle of the Hall current sensor zeroing system of the embodiment of the present application.

[0041] Explanation of the accompanying drawings: 1. Sampling module; 11. Second relay; 2. Signal processing module; 21. Amplifier; 22. In-phase adder; 3. Processing control module; 31. AD sampling unit; 32. Processing unit; 33. Control unit; 34. First DA output unit; 35. Second DA output unit; 4. Compensation module; 41. First relay; 42. Compensation power supply; 5. Power supply module; 51. First level conversion unit; 52. Second level conversion unit; 53. Third level conversion unit; 6. Hall current sensor; 7. Power supply unit; 8. Third relay; 9. Isolation module; 10. Display module. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical solutions and advantages of this application more clear, the following Figure 1-2 It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0043] The present application embodiment discloses a Hall current sensor zeroing system. Figure 1 The zero adjustment system of the Hall current sensor includes a sampling module 1, a signal processing module 2, a processing control module 3, a compensation module 4 and a power supply module 5. The processing control module 3 is used to determine whether the current Hall current sensor 6 has a zero drift problem, and is used to control the compensation module 4 to perform compensation when the current Hall current sensor 6 has a zero drift, so as to measure the resistance value of the compensation resistor, thereby alleviating the degree of zero drift of the Hall current sensor 6.

[0044] Specifically, the power module 5 is connected to the mains to provide multiple voltages. The power module 5 includes a first level conversion unit 51 , a second level conversion unit 52 and a third level conversion unit 53 .

[0045] The first level conversion unit 51 is used to access the 220V mains power and adjust the mains voltage to output a first amplitude voltage. In the present application, the first amplitude voltage is 24V.

[0046] The second level conversion unit 52 is connected to the first level conversion unit 51 and receives the first amplitude voltage, and is used to adjust the first amplitude voltage to output a second amplitude voltage. In the present application, the second amplitude voltage is 15V.

[0047] The third level conversion unit 53 is connected to the first level conversion unit 51 and receives the first amplitude voltage, and is used to adjust the first amplitude voltage to output a third amplitude voltage. In the present application, the third amplitude voltage is 5V.

[0048] It can be understood that filter units are connected between the first level conversion unit 51 and the 220V socket, between the second level conversion unit 52 and the first level conversion unit 51, and between the third level conversion unit 53 and the first level conversion unit to remove high-frequency interference.

[0049] The first level conversion unit 51 , the second level conversion unit 52 and the third level conversion unit 53 all have the function of voltage regulation, which belongs to conventional technical means in the relevant field, and thus will not be described in detail here.

[0050] The Hall current sensor 6 is connected to the second level conversion unit 52 , so that current flows through the primary side of the Hall current sensor 6 .

[0051] The sampling module 1 is connected to the secondary side of the Hall current sensor 6 and is used to sample the output voltage of the Hall current sensor 6 in real time and output a sampling signal after the Hall current sensor 6 is powered.

[0052] Specifically, the sampling module 1 includes a sampling resistor, which is used to sample the output voltage of the Hall current sensor 6 in real time when current flows through it, so as to reflect the actual situation of the output voltage of the Hall current sensor 6. Since the current flowing through the primary side of the Hall current sensor 6 has positive and negative values, the voltage value across the sampling resistor also has positive and negative values.

[0053] The signal processing module 2 is respectively connected to the second level conversion unit 52 and the sampling module 1 , and is used for receiving the sampling signal and processing the sampling signal to output an identification signal within an identifiable range.

[0054] Specifically, the signal processing module 2 includes an amplifier 21 and an in-phase adder 22 .

[0055] The amplifier 21 is connected to the sampling module 1, and is used to receive the sampling signal and amplify the voltage value reflected by the sampling signal. In the present application, the amplifier 21 is preferably a 2x amplifier 21. Of course, the amplification factor of the amplifier 21 can be adaptively adjusted according to actual conditions.

[0056] The in-phase adder 22 is connected to the amplifier 21, and is used to superimpose the voltage value reflected by the amplified sampling signal with the preset standard value to output an identification signal within the identifiable range. It can be understood that the voltage value reflected by the sampling signal has two positive and negative values, and the processing control module 3 used to identify the amplified sampling signal cannot identify the negative voltage value. Therefore, the voltage value reflected by the amplified sampling signal is superimposed with the preset standard value. Among them, the preset standard value is greater than the maximum value of the voltage value reflected by the amplified sampling signal, so that no matter how much the voltage value reflected by the sampling signal is, the value after amplification and superposition with the preset standard value is a positive number, so as to facilitate the processing control module 3 to identify. Preferably, the range that the processing control module 3 can identify is 0-5V, and correspondingly, the preset standard value is 2.5V.

[0057] The following is a specific example to facilitate understanding:

[0058] Assuming that the voltage across the sampling resistor is -0.6V, the voltage value reflected by the amplified sampling signal is -1.2V. Furthermore, the voltage value reflected by the identification signal after being superimposed with the preset standard value is 1.3V.

[0059] The processing control module 3 is connected to the third level conversion unit 53 and the signal processing unit 32 respectively, and is used to calculate the voltage value reflected by the sampling signal according to the identification signal, and output the compensation signal when the voltage value reflected by the sampling signal is not zero. The processing control module 3 includes an AD sampling unit 31, a processing unit 32 and a control unit 33.

[0060] Among them, the AD sampling unit 31 is connected to the in-phase adder 22, which is used to receive the identification signal and convert the analog identification signal into a digital identification signal. It can be understood that the AD sampling unit 31 can identify the voltage of 0-5V, but the voltage value reflected by the identification signal is not the voltage actually sampled by the sampling resistor. Therefore, in order to determine whether the Hall current sensor 6 generates a zero offset, it is necessary to calculate the voltage value reflected by the sampling signal through the voltage value reflected by the identification signal.

[0061] The AD sampling unit 31 connected to the processing unit 32 is used to receive the identification signal of the digital quantity and to calculate the voltage value reflected by the sampling signal according to the identification signal. Specifically, the method for calculating the voltage value reflected by the sampling signal is:

[0062]

[0063] Let’s use the example above to illustrate:

[0064] When the voltage value reflected by the identification signal is 1.3V, the voltage value reflected by the amplified sampling signal is -1.2V, and then the voltage value reflected by the sampling signal is -0.6V.

[0065] It is worth noting that the processing control unit 33 further includes a first DA output unit 34. The first DA output unit 34 is used to output the above-mentioned preset standard value.

[0066] The first DA output unit 34 is connected to a power supply unit 7. The power supply unit 7 is used to output a voltage with an amplitude of a preset standard value to be superimposed on the amplified sampling signal.

[0067] The control unit 33 is connected to the processing unit 32 and is used to determine whether the Hall current sensor 6 generates a zero offset. Specifically, when the voltage value reflected by the sampling signal is not zero, the control unit 33 outputs a high level, that is, outputs a compensation signal. On the contrary, when the voltage value reflected by the sampling signal is zero, the control unit 33 outputs a low level, that is, does not output a compensation signal, which indicates that the Hall current sensor 6 does not generate a zero offset at this time.

[0068] The compensation module 4 is connected to the processing control module 3 and is used to apply an adjustable compensation voltage to the Hall current sensor 6 when receiving the compensation signal, so that the voltage value currently reflected by the sampling signal is zero.

[0069] The compensation module 4 includes a first relay 41 and a compensation power source 42 .

[0070] The first relay 41 is connected to the control unit 33 and is used to close when receiving the compensation signal to output a trigger signal.

[0071] It can be understood that the processing control module 3 further includes a second DA output unit 35. The control unit 33 is connected to the second DA output unit 35, and is used to control the second DA output unit 35 to output a compensation voltage value while outputting the compensation signal.

[0072] The compensation power supply 42 is connected to the first relay 41 and the Hall current sensor 6 respectively, and is used to provide a compensation voltage for the Hall current sensor 6 when receiving a trigger signal. When the first relay 41 is closed, the compensation power supply 42 is connected to the second DA output unit 35, and can receive the compensation voltage value of the physical quantity to output the corresponding compensation voltage. On the contrary, when the first relay 41 is disconnected, the compensation power supply 42 is disconnected from the second DA output unit 35, that is, no compensation voltage is output.

[0073] It is worth noting that the compensation voltage output by the compensation circuit is not a specific voltage value, but needs to be adjusted by the processing control module 3, that is, by adjusting the compensation voltage, the voltage value reflected by the current sampling signal is made zero. In the embodiment of the present application, the approximate compensation method is mainly used, and the specific compensation steps are as follows:

[0074] First, the control unit 33 controls the compensation power supply 42 to output a voltage that is twice the initial value of the voltage reflected by the sampling signal. For example, if the voltage value reflected by the sampling signal is 0.6V, the compensation voltage is 1.2V.

[0075] Then, the compensation efficiency is calculated based on the voltage value reflected by the sampling signal and the voltage value of the sampling resistor after compensation, that is,

[0076] It can be obtained that the change in the voltage value reflected by the sampling signal during the Nth compensation is:

[0077] V N =Δ×V N-1

[0078] Secondly, the compensation voltage is adjusted in 4-fold steps, that is, 4 ADs are adjusted each time, and 1 AD is approximately 1.22mV.

[0079] Finally, when the voltage value reflected by the compensated sampling signal enters the limiting condition, the step size is readjusted to 1 times the step size for compensation until the voltage value reflected by the sampling signal is zero. Among them, the limiting condition is an adjustment condition set in advance by humans, and it is preferably that the voltage value reflected by the compensated sampling signal is less than 10 AD. Of course, the adjustment amount of each compensation voltage can be adaptively designed according to the actual situation.

[0080] The control unit 33 is also used to control the first relay 41 to disconnect when the voltage value reflected by the current sampling signal is zero. At this time, the processing unit 32 is also used to calculate the resistance of the compensation resistor according to the output voltage and the compensation voltage to output a resistance detection signal. Specifically, the resistance calculation formula of the compensation resistor is: Among them, V 3-1 is the compensation voltage on pins 1 and 3 of the Hall element of the Hall current sensor 6, V 4-2 is the voltage on pin 2 and pin 4 of the Hall element, R1 is a fixed resistor with a resistance of 240KΩ.

[0081] Reference Figure 1 and Figure 2It can be understood that the fixed resistor R1 is connected in series between pins 1 and 3 of the Hall element, and the compensation resistor R is connected in series between pins 2 and 4 of the Hall element. Since the current flowing through pins 1 and 3 of the Hall element is equal to the current flowing through pins 2 and 4 of the Hall element, Of course, the compensation resistor R can also be regarded as two compensation resistors R 补 In series, we can get Among them, R 补 =1 / 2×R.

[0082] The Hall current sensor zeroing system in the present application can not only detect whether the Hall current sensor 6 has zero drift and perform zeroing on the Hall current sensor 6 that has zero drift, but also detect the linearity of the Hall current sensor 6 .

[0083] Specifically, there are two sampling resistors, sampling resistor R A and sampling resistor R B The sampling module 1 further includes a second relay 11. The second relay 11 is connected in parallel with any sampling resistor, and the second relay 11 is connected to the control unit 33 to be closed or opened under the control of the control unit 33, thereby realizing the linear detection of the Hall current sensor 6.

[0084] Moreover, a switch element is connected between the second level conversion unit 52 and the first level conversion unit 51 , and a third relay 8 is connected between the Hall current sensor 6 and the second level conversion unit 52 . The third relay 8 is connected to the control unit 33 for cutting off or turning on the power supply of the Hall current sensor 6 .

[0085] In addition, the in-phase adder 22 and the 2-times amplifier 21 as well as the first relay 41 and the processing control module 3 are all connected via the isolation module 9. The isolation module 9 is a conventional technical means in the relevant field, so no further explanation is given here.

[0086] The processing control module 3 mentioned above is preferably a MCU single chip computer.

[0087] The display module 10 is also included, and the display module 10 is connected to the processing unit 32 and is used to receive the resistance detection signal and display the corresponding resistance value. Preferably, the display module 10 is a display screen.

[0088] The implementation principle of a zero adjustment system for a Hall current sensor in an embodiment of the present application is as follows: the output voltage of the Hall current sensor 6 is sampled by the sampling module 1, and whether the Hall current sensor 6 has a zero drift is determined according to the voltage value reflected by the sampling signal. When the Hall current sensor 6 has a zero drift, the compensation module 4 is turned on to apply a compensation voltage to the Hall current sensor 6, so that the voltage value reflected by the sampling signal is zero, thereby achieving zero adjustment of the Hall current sensor 6. At the same time, the resistance value of the compensation resistor is calculated according to the output voltage of the Hall current sensor 6 and the compensation voltage.

[0089] The above are all preferred embodiments of the present application, and are not intended to limit the protection scope of the present application. Any feature disclosed in this specification (including the abstract and drawings), unless otherwise stated, can be replaced by other equivalent or alternative features with similar purposes. That is, unless otherwise stated, each feature is only an example of a series of equivalent or similar features.

Claims

1. A Hall current sensor zeroing system, characterized in that: include: A sampling module (1), a signal processing module (2), a processing control module (3), a compensation module (4) and a power supply module (5); The sampling module (1) is used to sample the output voltage of the Hall current sensor (6) in real time after the Hall current sensor (6) is powered on, so as to output a sampling signal; The signal processing module (2) is connected to the sampling module (1) and is used to process the sampled signal to output an identification signal within an identifiable range; The signal processing module (2) comprises an amplifier (21) and an in-phase adder (22); The amplifier (21) is used to amplify the sampling signal; The in-phase adder (22) is connected to the amplifier (21) and is used to add the voltage value reflected by the amplified sampling signal and the preset standard value to output an identification signal within the identifiable range; The processing control module (3) is connected to the signal processing module (2) and is used to calculate the voltage value reflected by the sampling signal according to the identification signal, and output a compensation signal when the voltage value reflected by the sampling signal is not zero; The compensation module (4) is connected to the processing control module (3) and is used to apply an adjustable compensation voltage to the Hall current sensor (6) when receiving the compensation signal, so that the voltage value reflected by the current sampling signal is zero; the processing control module (3) is also used to calculate the resistance value of the compensation resistor configured on the Hall current sensor (6) according to the output voltage and the compensation voltage, so as to output a resistance detection signal; The power supply module (5) is respectively connected to the sampling module (1), the signal processing module (2), the processing control module (3) and the compensation module (4), and is connected to the mains to provide a variety of voltages; Wherein, the processing control module (3) is connected to a display module (10), and the display module (10) is used to receive the resistance detection signal and to display the resistance value of the compensation resistor; Wherein, the resistance calculation formula of the compensation resistor is: , where V 3-1 is the compensation voltage on pin 1 and pin 3 of the Hall element of the Hall current sensor (6), V 4-2 is the voltage on pin 2 and pin 4 of the Hall element, R1 is a fixed resistor; the fixed resistor R1 is connected in series between pin 1 and pin 3 of the Hall element, and the compensation resistor R is connected in series between pin 2 and pin 4 of the Hall element.

2. The Hall current sensor zeroing system according to claim 1, characterized in that: The amplifier (21) is a 2x amplifier (21).

3. The Hall current sensor zeroing system according to claim 2, characterized in that: The compensation module (4) comprises a first relay (41) and a compensation power supply (42); The first relay (41) is connected to the processing control module (3) and is used to close when receiving the compensation signal to output a trigger signal; The compensation power supply (42) is respectively connected to the first relay (41) and the Hall current sensor (6), and is used to provide a compensation voltage for the Hall current sensor (6) when receiving the trigger signal.

4. The Hall current sensor zeroing system according to claim 3, characterized in that: The processing control module (3) is an MCU.

5. The Hall current sensor zeroing system according to claim 4, characterized in that: The in-phase adder (22) and the 2x amplifier (21) as well as the first relay (41) and the processing control module (3) are all connected via an isolation module (9).

6. The Hall current sensor zeroing system according to claim 1, characterized in that: The sampling module (1) comprises a second relay (11) and two sampling resistors, the two sampling resistors are connected in series, the second relay (11) is connected in parallel with one of the sampling resistors, and the processing control module (3) is connected to the second relay (11) and is also used to control the second relay (11) to close or open.

7. The Hall current sensor zeroing system according to claim 1, characterized in that: The power module (5) comprises a first level conversion unit (51), a second level conversion unit (52) and a third level conversion unit (53); The first level conversion unit (51) is connected to the mains power supply and is used to change the mains power voltage to output a first amplitude voltage; The second level conversion unit (52) is connected to the first level conversion unit (51), receives the first amplitude voltage, and is used to change the first amplitude voltage to output a second amplitude voltage; The third level conversion unit (53) is connected to the first level conversion unit (51), receives the first amplitude voltage, and is used to change the first amplitude voltage to output a third amplitude voltage.

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