Automatic compensation circuit based on bias error of Hall current sensor

By designing an automatic compensation circuit based on bias error of Hall current sensor, the signal conditioning circuit is used to calibrate the bias error caused by the change in the supply voltage in real time, the acquisition of Hall current sensor due to the change in the supply voltage in the motor control system is solved. The current conversion deviation problem realizes automatic elimination of bias errors and reduction of system costs.

CN222482631UActive Publication Date: 2025-02-14HEFEI JUYI POWER SYST CO LTD
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Patent Information

Application Number
CN202421141559.1
Authority / Receiving Office
CN · China
Patent Type
Utility models(China)
Current Assignee / Owner
Filing Date
2024-05-23
Publication Date
2025-02-14
Estimated Expiration
2034-05-23

AI Technical Summary

Technical Problem

The Hall current sensor in the motor control system has a current conversion deviation caused by the change in the supply voltage, which affects the control performance and operating efficiency of the motor.

Method used

Design an automatic compensation circuit based on bias error of Hall current sensor, and calibrate the bias error caused by changes in the supply voltage through the signal conditioning circuit in real time, including Hall current sensor and signal conditioning circuit, and use resistors, capacitors and amplifiers to achieve bias Automatic compensation of voltage.

Benefits of technology

Effectively reduce the bias error of Hall sensor current sampling, reduce the accuracy requirements of power supply, realize automatic elimination of bias errors, improve product reliability and reduce system costs.

✦ Generated by Eureka AI based on patent content.

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Abstract

The utility model discloses an automatic compensation circuit based on a Hall current sensor bias error. The automatic compensation circuit comprises a Hall current sensor T5 and a signal conditioning circuit. A pin 1 of the Hall current sensor T5 is connected with a power supply VCC and is connected with a grounding end GND through a capacitor C356; a pin 3 of the Hall current sensor T5 is connected with a grounding end GND; and the signal conditioning circuit comprises resistors R388 to R393, capacitors C354 to C361 and an amplifier U34. The automatic compensation circuit based on the bias error of the Hall current sensor has the advantages that the bias error of current sampling of the Hall sensor can be effectively reduced, the precision requirement of a power supply is reduced, the bias error is automatically eliminated, the reliability of a product is improved, the system cost is reduced and the like.
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Description

Technical Field

[0001] The utility model relates to a voltage compensation technology, in particular to an automatic compensation circuit based on a bias error of a Hall current sensor. Background Art

[0002] High current detection technology is widely used in the fields of industrial automation, electric vehicles, power transmission, monitoring and maintenance of electrical equipment, etc. At present, the common high current detection technologies mainly include resistive shunt method and Hall effect current detection method. The resistive shunt method measures the voltage drop on the resistor carrying the current (and charge) to be measured. The voltage drop follows Ohm's law (V=I*R). The current value to be measured is calculated by the voltage drop. Since the shunt resistor is always heated by the current flowing through it, there are heat dissipation problems, it is greatly affected by temperature, the error is large, and electrical isolation cannot be achieved during measurement, which poses a safety hazard.

[0003] The Hall current sensor is made according to the Hall effect principle and is used to measure a magnetic field proportional to the current generated around a current-carrying conductor, which can achieve non-contact measurement of current. Due to the wide measurement range, fast response speed, high measurement accuracy, wide working frequency band, and isolation function of the Hall current sensor, it is often used in the field of motor drive to collect motor phase current signals.

[0004] Since the reference voltage corresponding to the zero current of the Hall current sensor will change according to the size of the power supply voltage, the sampling current reference value is set as a constant in the motor control system. When the size of the power supply voltage of the Hall current sensor changes, the conversion of the collected motor phase current will deviate, affecting the control performance and operating efficiency of the motor.

[0005] my country's invention patent with patent application number 2023103459600 discloses a method for self-adjustment of current reference value based on Hall current sensor sampling. The invention increases the signal acquisition of the Hall current sensor power supply voltage and adds the power supply voltage to the judgment basis of the current reference value self-adjustment. When the motor is disabled, the output voltage of the current sensor is directly used as the current reference value. When the motor is enabled, the current reference value is adjusted by the sensor power supply voltage and the static deviation, thereby completing the self-adjustment of the motor's static and dynamic state reference current.

[0006] In the invention patent of the above-mentioned prior art, the error is calibrated by collecting the change in power supply voltage and adjusting it in real time through software compensation. There are two problems: (1) First, the error and fluctuation range of the power supply itself is relatively narrow. If you want to accurately collect the error, you need to perform high-precision sampling on it, which will increase the cost of the device or make it difficult to achieve; (2) Secondly, software calibration usually has a large delay, which makes it difficult to compensate and calibrate in real time, which may cause the error to increase.

[0007] Therefore, it is urgent to design a compensation circuit that can compensate for the measurement error of the Hall current sensor and ensure the measurement accuracy. Utility Model Content

[0008] The utility model aims to avoid the deficiencies existing in the above-mentioned prior art and provides an automatic compensation circuit based on the bias error of a Hall current sensor, so as to effectively reduce the bias error of the Hall sensor current sampling.

[0009] The utility model adopts the following technical solutions to solve the technical problems.

[0010] The utility model discloses an automatic compensation circuit based on the bias error of a Hall current sensor, comprising a Hall current sensor T5 and a signal conditioning circuit; a pin 1 of the Hall current sensor T5 is connected to a power supply VCC, and is connected to a ground terminal GND through a capacitor C356; a pin 3 of the Hall current sensor T5 is connected to a ground terminal GND;

[0011] The signal conditioning circuit includes resistors R388-R393, capacitors C354-C361 and amplifier U34;

[0012] Pin 2 of the Hall current sensor T5 is connected to pin 3 of the amplifier U34 via resistor R389;

[0013] One end of the resistor R388 and the capacitor C357 connected in parallel is connected to the pin 3 of the amplifier U34, and the other end of the resistor R388 and the capacitor C357 connected in parallel is the output end of the bias voltage Vbias_1.65V and is connected to the ground terminal GND through the capacitor C355; the pin 1 of the amplifier U34 is the output end of the current Is;

[0014] Pin 4 of the amplifier U34 is connected to the ground terminal GND; Pin 8 of the amplifier U34 is connected to the power supply VCC and is connected to the ground terminal GND through C354;

[0015] One end of the resistor R391 connected in parallel with the capacitor C359 is connected to the pin 2 of the amplifier U34, and the other end of the resistor R388 connected in parallel with the capacitor C357 is connected to the pin 1 of the amplifier U34;

[0016] One end of the resistor R390 is connected to the pin 2 of the amplifier U34, and the other end of the resistor R390 is the output end of the bias voltage Vbias_2.5V and is connected to the ground end GND through the capacitor C358;

[0017] One end of the resistor R393 connected in parallel with the capacitor C360 is connected to the pin 5 of the amplifier U34, and the pin 5 of the amplifier U34 is also connected to the power supply VCC through the resistor R392;

[0018] The pin 6 of the amplifier U34 is connected to the pin 7 of the amplifier U34 , and the pin 7 of the amplifier U34 is connected to the output terminal of the bias voltage Vbias_2.5V and is connected to the ground terminal GND through the capacitor C361 .

[0019] The structural characteristics of the automatic compensation circuit based on the bias error of the Hall current sensor of the utility model are also as follows:

[0020] Furthermore, the amplifier U34 is an operational amplifier SGM8622XS / TR.

[0021] Furthermore, the resistance value of the resistor R389 is the same as the resistance value of the resistor R390.

[0022] Furthermore, the resistance values ​​of the resistor R388, the resistor R391, the resistor R392 and the resistor R393 are the same.

[0023] Compared with the prior art, the beneficial effects of the utility model are embodied in:

[0024] The utility model discloses an automatic compensation circuit based on the bias error of a Hall current sensor, comprising a Hall current sensor T5 and a signal conditioning circuit; a pin 1 of the Hall current sensor T5 is connected to a power supply VCC, and is connected to a ground terminal GND through a capacitor C356; a pin 3 of the Hall current sensor T5 is connected to a ground terminal GND; and the signal conditioning circuit comprises resistors R388-R393, capacitors C354-C361 and an amplifier U34.

[0025] The utility model discloses an automatic compensation circuit based on the bias error of the Hall current sensor, which has the advantages of being able to effectively reduce the bias error of the Hall sensor current sampling and lower the accuracy requirement of the power supply, realize automatic elimination of the bias error, improve product reliability, and reduce system cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The utility model is a schematic diagram of a framework of an automatic compensation circuit based on the bias error of a Hall current sensor.

[0027] Figure 2 The utility model is a circuit schematic diagram of an automatic compensation circuit based on the bias error of a Hall current sensor.

[0028] The present invention is further described below through specific implementation methods in conjunction with the accompanying drawings. DETAILED DESCRIPTION

[0029] See also Figure 1-2 The utility model is an automatic compensation circuit based on the bias error of a Hall current sensor, comprising a Hall current sensor T5 and a signal conditioning circuit; a pin 1 of the Hall current sensor T5 is connected to a power supply VCC, and is connected to a ground terminal GND through a capacitor C356; a pin 3 of the Hall current sensor T5 is connected to a ground terminal GND;

[0030] The signal conditioning circuit includes resistors R388-R393, capacitors C354-C361 and amplifier U34;

[0031] Pin 2 of the Hall current sensor T5 is connected to pin 3 of the amplifier U34 via resistor R389;

[0032] One end of the resistor R388 and the capacitor C357 connected in parallel is connected to the pin 3 of the amplifier U34, and the other end of the resistor R388 and the capacitor C357 connected in parallel is the output end of the bias voltage Vbias_1.65V and is connected to the ground terminal GND through the capacitor C355; the pin 1 of the amplifier U34 is the output end of the current Is;

[0033] Pin 4 of the amplifier U34 is connected to the ground terminal GND; Pin 8 of the amplifier U34 is connected to the power supply VCC and is connected to the ground terminal GND through C354;

[0034] One end of the resistor R391 connected in parallel with the capacitor C359 is connected to the pin 2 of the amplifier U34, and the other end of the resistor R388 connected in parallel with the capacitor C357 is connected to the pin 1 of the amplifier U34;

[0035] One end of the resistor R390 is connected to the pin 2 of the amplifier U34, and the other end of the resistor R390 is the output end of the bias voltage Vbias_2.5V and is connected to the ground end GND through the capacitor C358;

[0036] One end of the resistor R393 connected in parallel with the capacitor C360 is connected to the pin 5 of the amplifier U34, and the pin 5 of the amplifier U34 is also connected to the power supply VCC through the resistor R392;

[0037] The pin 6 of the amplifier U34 is connected to the pin 7 of the amplifier U34 , and the pin 7 of the amplifier U34 is connected to the output terminal of the bias voltage Vbias_2.5V and is connected to the ground terminal GND through the capacitor C361 .

[0038] In a specific implementation, the amplifier U34 is an operational amplifier SGM8622XS / TR.

[0039] During specific implementation, the resistance value of the resistor R389 is the same as the resistance value of the resistor R390.

[0040] During specific implementation, the resistance values ​​of the resistor R388 , the resistor R391 , the resistor R392 and the resistor R393 are the same.

[0041] The operational amplifier U34 is a low-noise, low-voltage, low-power operational amplifier SGM8622XS / TR. The SGM8622 has ultra-low noise, ultra-low voltage, and designed low power consumption, and is widely used in various high-end devices. The gain bandwidth of the SGM8622 is up to 6MHz, which means that it can maintain a stable gain at high frequencies, ensuring signal stability, and the slew rate reaches 3.7V / μs. The SGM8622 can operate over a wide temperature range and adapt to various harsh environments. At the same time, its operating power supply range is also very wide, and it can work normally from 2V to 5.5V. Moreover, the rail-to-rail output swing and low input offset voltage of the SGM8622 make it have excellent performance in low-voltage and low-noise systems.

[0042] like Figure 1-2 The output voltage of the Hall sampling chip currently used for motor control satisfies the characteristics of the following formula (1).

[0043] Vout=V0 + G*Ip* Vcc / 5 (1)

[0044] In formula (1), Vout is the output voltage of the Hall sensor; Vcc is the power supply voltage; Ip is the operating current; V0 is the zero current bias voltage, satisfying the condition: V0=Vcc / 2; G is the current sampling gain.

[0045] like Figure 2 As shown, the utility model is an automatic compensation circuit based on the bias error of the Hall current sensor, which has the following technical characteristics.

[0046] 1. The Hall current sensor T5 is responsible for converting the three-phase AC current into a voltage signal. When the three-phase AC current is 0, the Hall current sensor T5 outputs a bias voltage Vbias_T5; the bias voltage Vbias_T5 output by T5 is the V0 voltage output by T5, that is, Vbias_T5 = Vcc / 2;

[0047] 2. The bias voltage Vbias_T5 is related to the supply voltage Vcc;

[0048] 3. The voltage signal Vk output by the Hall current sensor T5 is conditioned by the signal conditioning circuit and then sent to the MCU, which uses the conditioned voltage signal Vk for motor control. In the present utility model, the MCU can be a conventional processor, such as TMS320F280049, TMS5701115BPGEQ, TMS320F28379 or

[0049] Processors of models such as SAK-TC277TP-64F200N.

[0050] 4. During the specific working process, the power supply voltage Vcc may fluctuate due to the influence of temperature, load, input power supply or device parameter differences, which in turn causes the bias voltage to change, thereby causing errors in the sampling signal, resulting in system failure or abnormal operation; the signal conditioning circuit of the utility model can calibrate the bias error caused by Vcc in real time to ensure signal quality.

[0051] like Figure 2 In the formula (1), the output voltage Vout of the Hall current sensor T5 is shown in formula (1).

[0052] The calculation formula of the current Is is shown in the following formula (2).

[0053] Is=(Vout-Vbias_2.5V)*R391 / R390+Vbias_1.65V (2);

[0054] The calculation formula of the bias voltage Vbias_2.5V is shown in the following formula (3). Vbias_2.5V is a bias voltage used to offset V0 in the subsequent conditioning circuit, that is, V0 = Vbias_2.5V. Figure 2 In the circuit, the relationship between the resistance values ​​of resistors R388 to R393 is: R389=R390, R388=R391=R392==R393.

[0055]

[0056] According to formula (1), formula (2) and formula (3), the following formula (4) can be obtained.

[0057] Is=(G*Ip* Vcc / 5)*(R391 / R390)+Vbias_1.65V (4);

[0058] It can be seen from formula (4) that V0 cancels out Vbias_2.5V of the differential sampling circuit; Vbias_2.5V in the circuit is obtained by direct voltage division of Vcc; when the power supply voltage Vcc of the Hall current sensor T5 changes, V0 and Vbias_2.5V of the Hall current sensor T5 cancel out each other, so that the power supply voltage Vcc no longer affects V0.

[0059] Vbias_1.65V is a new bias voltage added after Vbias_2.5V offsets V0. For example, when V0 outputs 2.5V, it means the current is 0A. After passing through this circuit, it outputs 1.65V, which means 0A. Vbias_1.65V is used as the output bias voltage of Is.

[0060] The utility model discloses an automatic compensation circuit based on the bias error of the Hall current sensor, which can effectively reduce the bias error of the Hall sensor current sampling and reduce the accuracy requirement of the power supply, realize the automatic elimination of the bias error, thereby improving the reliability of the product and reducing the system cost.

[0061] The utility model is based on the automatic compensation circuit of the Hall current sensor bias error, which has the following advantages:

[0062] 1. Decoupling the current bias and supply voltage of the Hall current sensor is achieved through hardware circuit.

[0063] 2. The stability requirements of the system power supply are greatly reduced, and more common devices can be selected, which reduces the system cost and makes the devices more replaceable;

[0064] 3. General fluctuations in temperature, power supply, and load may cause unstable sensor power supply voltage, thereby affecting the current sampling accuracy. The circuit of the utility model can effectively reduce the impact of temperature fluctuations, power supply fluctuations, and load fluctuations, and improve product reliability.

[0065] It is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be regarded as exemplary and non-restrictive from any point of view, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention. Any reference numeral in a claim should not be regarded as limiting the claim to which it relates.

[0066] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. An automatic compensation circuit based on Hall current sensor bias error, characterized in that: It includes a Hall current sensor T5 and a signal conditioning circuit; the pin 1 of the Hall current sensor T5 is connected to the power supply VCC and connected to the ground terminal GND through the capacitor C356; the pin 3 of the Hall current sensor T5 is connected to the ground terminal GND; The signal conditioning circuit includes resistors R388-R393, capacitors C354-C361 and amplifier U34; Pin 2 of the Hall current sensor T5 is connected to pin 3 of the amplifier U34 via resistor R389; One end of the resistor R388 and the capacitor C357 connected in parallel is connected to the pin 3 of the amplifier U34, and the other end of the resistor R388 and the capacitor C357 connected in parallel is the output end of the bias voltage Vbias_1.65V and is connected to the ground terminal GND through the capacitor C355; the pin 1 of the amplifier U34 is the output end of the current Is; Pin 4 of the amplifier U34 is connected to the ground terminal GND; Pin 8 of the amplifier U34 is connected to the power supply VCC and is connected to the ground terminal GND through C354; One end of the resistor R391 connected in parallel with the capacitor C359 is connected to the pin 2 of the amplifier U34, and the other end of the resistor R388 connected in parallel with the capacitor C357 is connected to the pin 1 of the amplifier U34; One end of the resistor R390 is connected to the pin 2 of the amplifier U34, and the other end of the resistor R390 is the output end of the bias voltage Vbias_2.5V and is connected to the ground end GND through the capacitor C358; One end of the resistor R393 connected in parallel with the capacitor C360 is connected to the pin 5 of the amplifier U34, and the pin 5 of the amplifier U34 is also connected to the power supply VCC through the resistor R392; The pin 6 of the amplifier U34 is connected to the pin 7 of the amplifier U34 , and the pin 7 of the amplifier U34 is connected to the output terminal of the bias voltage Vbias_2.5V and is connected to the ground terminal GND through the capacitor C361 .

2. The automatic compensation circuit based on the bias error of the Hall current sensor according to claim 1 is characterized in that: The amplifier U34 is an operational amplifier SGM8622XS / TR.

3. The automatic compensation circuit based on the bias error of the Hall current sensor according to claim 1 is characterized in that: The resistance value of the resistor R389 is the same as the resistance value of the resistor R390.

4. The automatic compensation circuit based on the bias error of the Hall current sensor according to claim 1 is characterized in that: The resistance values ​​of the resistor R388 , the resistor R391 , the resistor R392 and the resistor R393 are the same.