Current sampling bias calibration circuit and vehicle motor detection equipment

Abstract

The utility model discloses a current sampling bias calibration circuit and a vehicle motor detection device, which relate to the technical field of circuits and comprise a sampling circuit and a calibration circuit arranged corresponding to the sampling circuit. The input end of the sampling circuit collects a sampling value of target phase power through a current sensor, and the output end of the sampling circuit is connected with a sampling feedback port of the micro-control unit; the input end of the calibration circuit is connected with a first voltage end, the output end of the calibration circuit is connected with a calibration feedback port of the micro-control unit, and the voltage of the first voltage end is the output voltage when the current sensor has no current; under the condition that the output voltage of the current sensor is larger than a first threshold value when no current exists, the calibration circuit and the sampling circuit are each provided with a voltage amplitude attenuation module used for adjusting the feedback value output to the micro-control unit to be within the voltage acquisition range of the analog-to-digital converter corresponding to the micro-control unit. The first threshold value is determined according to the voltage acquisition range of the analog-to-digital converter. Therefore, the sampling accuracy is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of circuits, in particular to a current sampling bias calibration circuit and a vehicle motor detection device. Background Art

[0002] The main purpose of the vehicle motor current sampling circuit is to detect the working current of the motor to facilitate precise control of the control system and the implementation of protection measures.

[0003] At present, Hall current sensor modules are widely used for high current sampling of new energy motors. However, the current sampling circuit is often built with electrical components such as resistors and operational amplifiers, which introduces error sources such as power supply, resistors and operational amplifiers, and causes deviations from the actual current sensor output voltage value, resulting in inaccurate sampling. Utility Model Content

[0004] Based on the above problems, the utility model provides a current sampling bias calibration circuit and a vehicle motor detection device to reduce the error of current sampling and improve the accuracy of current sampling.

[0005] The utility model embodiment discloses the following technical solution:

[0006] In a first aspect, the present application provides a current sampling bias calibration circuit, comprising a sampling circuit and a calibration circuit arranged corresponding to the sampling circuit;

[0007] The input end of the sampling circuit collects the sampled value of the target phase electricity through the current sensor, and the output end of the sampling circuit is connected to the sampling feedback port of the micro control unit; the input end of the calibration circuit is connected to the first voltage end, and the output end of the calibration circuit is connected to the calibration feedback port of the micro control unit, and the voltage of the first voltage end is the output voltage of the current sensor when there is no current;

[0008] When the output voltage of the current sensor when there is no current is greater than a first threshold value, the calibration circuit and the sampling circuit are both provided with a voltage amplitude attenuation module for adjusting the feedback value output to the microcontroller unit within the voltage acquisition range of the analog-to-digital converter corresponding to the microcontroller unit, and the first threshold value is determined according to the voltage acquisition range of the analog-to-digital converter.

[0009] Optionally, the sampling circuit includes a sampling operational amplifier and a first processing module connected to an output end of the sampling operational amplifier, and the output end of the first processing module is connected to the sampling feedback port;

[0010] The calibration circuit comprises a calibration operational amplifier and a second processing module connected to the output end of the calibration operational amplifier, the output end of the second processing module is connected to the calibration feedback port; the first processing module and the second processing module both comprise a filtering submodule;

[0011] In the case that the output voltage of the current sensor when there is no current is greater than a first threshold, the sampling operational amplifier and the calibration operational amplifier are both provided with the voltage amplitude attenuation module.

[0012] Optionally, the voltage amplitude attenuation module includes a common bias voltage input submodule and a reverse bias voltage input submodule;

[0013] The same-direction input terminal of the calibration operational amplifier and the same-direction input terminal of the sampling operational amplifier are both provided with a same-direction bias voltage input submodule,

[0014] The reverse input terminal of the calibration operational amplifier and the reverse input terminal of the sampling operational amplifier are both provided with a reverse bias voltage submodule;

[0015] The voltage output by the reverse bias voltage submodule to the corresponding reverse input terminal is the same as the output voltage of the current sensor when there is no current.

[0016] Optional,

[0017] The same-direction bias voltage input submodule comprises a first resistor and a first power supply end, the voltage of the first power supply end is the first threshold, the first power supply end is connected to the first end of the first resistor, and the second end of the first resistor is connected to the same-direction input end corresponding to the same-direction bias voltage input submodule;

[0018] In the sampling circuit, the second end of the first resistor is also connected to the first end of the second resistor, and the second end of the second resistor is the input end of the sampling circuit;

[0019] In the calibration circuit, the second end of the first resistor is also connected to the first voltage end, the first voltage end is connected to the first end of the third resistor, the second end of the third resistor is connected to the second power supply end, the first voltage end is also connected to the first end of the fourth resistor, and the second end of the fourth resistor is grounded.

[0020] Optional,

[0021] The reverse bias voltage submodule includes a fifth resistor and a sixth resistor, wherein the first end of the fifth resistor and the first end of the sixth resistor are both connected to the reverse input end corresponding to the reverse bias voltage submodule, the second end of the fifth resistor is connected to the third power supply end, and the second end of the sixth resistor is grounded.

[0022] Optionally, the second power supply terminal and the third power supply terminal are the same power supply terminal, the resistance value of the third resistor is the same as the resistance value of the fourth resistor, the resistance value of the fifth resistor is the same as the resistance value of the sixth resistor, and the voltage of the second power supply terminal is twice the output voltage of the current sensor when there is no current.

[0023] Optionally, the first processing module further includes a first voltage clamping module, and the second processing module further includes a second voltage clamping module;

[0024] The filtering submodule of the first processing module includes a seventh resistor and a first filtering capacitor, the output end of the sampling operational amplifier is connected to the first end of the seventh resistor, the second end of the seventh resistor is connected to the first node of the first voltage clamping module, the first node of the first voltage clamping module is connected to the first end of the first filtering capacitor, the first node of the first voltage clamping module is also connected to the output end of the sampling circuit, and the second end of the first filtering capacitor is grounded; the first voltage clamping module includes a first diode and a second diode, the positive electrode of the first diode and the negative electrode of the second diode are connected to the first node of the first voltage clamping module, the negative electrode of the first diode is connected to the fourth power supply end, the positive electrode of the second diode is grounded, and the voltage of the fourth power supply end is the maximum value of the voltage acquisition range of the analog-to-digital converter;

[0025] The filtering submodule of the second processing module includes an eighth resistor and a second filtering capacitor, the output end of the calibration operational amplifier is connected to the first end of the eighth resistor, the second end of the eighth resistor is connected to the first node of the second voltage clamping module, the first node of the second voltage clamping module is connected to the first end of the second filtering capacitor, the first node of the second voltage clamping module is also connected to the output end of the calibration circuit, and the second end of the second filtering capacitor is grounded; the second voltage clamping module includes a third diode and a fourth diode, the anode of the third diode and the cathode of the fourth diode are connected to the first node of the second voltage clamping module, the cathode of the third diode is connected to the fourth power supply end, the anode of the fourth diode is grounded, and the voltage of the fourth power supply end is the maximum value of the voltage acquisition range of the analog-to-digital converter.

[0026] Optionally, the first processing module further includes a first voltage clamping module;

[0027] The filtering submodule of the first processing module includes a seventh resistor and a first filtering capacitor, the output end of the sampling operational amplifier is connected to the first end of the seventh resistor, the second end of the seventh resistor is connected to the first node of the first voltage clamping module, the first node of the first voltage clamping module is connected to the first end of the first filtering capacitor, the first node of the first voltage clamping module is also connected to the output end of the sampling circuit, and the second end of the first filtering capacitor is grounded; the first voltage clamping module includes a first diode and a second diode, the positive electrode of the first diode and the negative electrode of the second diode are connected to the first node of the first voltage clamping module, the negative electrode of the first diode is connected to the fourth power supply end, the positive electrode of the second diode is grounded, and the voltage of the fourth power supply end is the maximum value of the voltage acquisition range of the analog-to-digital converter;

[0028] The filtering submodule of the second processing module includes an eighth resistor and a second filtering capacitor. The output end of the calibration operational amplifier is connected to the first end of the eighth resistor, the second end of the eighth resistor is connected to the first end of the second filtering capacitor, the second end of the second filtering capacitor is grounded, and the second end of the eighth resistor is also connected to the output end of the calibration circuit.

[0029] Optionally, the circuit includes a plurality of the sampling circuits;

[0030] The input end of the first sampling circuit inputs the sampling value of the first phase electricity of the motor to be sampled, and the output end of the first sampling circuit is connected to the first sampling feedback port of the micro control unit;

[0031] The input end of the second sampling circuit inputs the sampling value of the second phase electricity of the motor to be sampled, and the output end of the second sampling circuit is connected to the second sampling feedback port of the micro control unit;

[0032] and / or,

[0033] The input end of the first sampling circuit inputs the sampling value of the first phase electricity of the motor to be sampled, and the output end of the first sampling circuit is connected to the first sampling feedback port of the micro control unit;

[0034] The input end of the second sampling circuit inputs the sampling value of the second phase electricity of the motor to be sampled, and the output end of the second sampling circuit is connected to the second sampling feedback port of the micro control unit;

[0035] The input end of the third sampling circuit inputs the sampling value of the third phase electricity of the motor to be sampled, and the output end of the third sampling circuit is connected to the third sampling feedback port of the micro control unit.

[0036] In a second aspect, the present application also provides a vehicle motor detection device, which adopts a current sampling bias calibration circuit described in any one of the above items.

[0037] Compared with the prior art, the utility model has the following beneficial effects:

[0038] The utility model provides a current sampling bias calibration circuit and a vehicle motor detection device, comprising a sampling circuit and a calibration circuit corresponding to the sampling circuit; the input end of the sampling circuit collects the sampling value of the target phase electricity through a current sensor, and the output end of the sampling circuit is connected to the sampling feedback port of a micro control unit; the input end of the calibration circuit is connected to a first voltage end, and the output end of the calibration circuit is connected to the calibration feedback port of the micro control unit, and the voltage of the first voltage end is the output voltage of the current sensor when there is no current; when the output voltage of the current sensor when there is no current is greater than a first threshold, the calibration circuit and the sampling circuit are both provided with a voltage amplitude attenuation module for adjusting the feedback value output to the micro control unit within the voltage acquisition range of the analog-to-digital converter corresponding to the micro control unit, and the first threshold is determined according to the voltage acquisition range of the analog-to-digital converter. While the sampling circuit is provided, the calibration circuit is further provided in parallel, and the first voltage end is connected to the input end of the calibration circuit, so that the calibration circuit outputs a feedback value based on the voltage of the first voltage end and accumulates the error generated by the calibration circuit. The calibration circuit corresponds to the circuit structure setting of the sampling circuit, and the accumulated errors in the calibration circuit and the sampling circuit are approximately or identical, so that the microcontroller unit can adjust the feedback value of the output end of the sampling circuit based on the accumulated error of the feedback value of the calibration circuit relative to the voltage of the first voltage end, and obtain the sampling value of the input end of the sampling circuit, thereby reducing the error caused by factors such as the components in the sampling circuit and the ambient temperature, and improving the sampling accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0040] Figure 1 A schematic diagram of the structure of a current sampling bias calibration circuit provided by the utility model;

[0041] Figure 2 A schematic diagram of the structure of a sampling operational amplifier in a sampling circuit provided by the utility model, in which a common bias voltage submodule and a reverse bias voltage submodule are arranged;

[0042] Figure 3A schematic diagram of the structure of a calibration circuit provided by the utility model for arranging a common bias voltage submodule and a reverse bias voltage submodule for a calibration operational amplifier;

[0043] Figure 4 A schematic diagram of the structure of a sampling circuit provided by the utility model;

[0044] Figure 5 A schematic diagram of the structure of a calibration circuit provided by the utility model;

[0045] Figure 6 A schematic diagram of a structure of configuring two sampling circuits and one calibration circuit in a three-phase motor provided by the utility model;

[0046] Figure 7 Another structural schematic diagram of configuring two sampling circuits and one calibration circuit in a three-phase motor provided by the utility model;

[0047] Figure 8 The utility model provides a structural schematic diagram of respectively setting sampling circuits for three phases of a three-phase motor.

[0048] Description of Figure Numbers

[0049] 1-first resistor; 2-second resistor; 3-first power supply terminal; 4-third resistor; 5-fourth resistor; 6-second power supply terminal; 7-fifth resistor; 8-sixth resistor; 9-third power supply terminal; 10-gain adjustment resistor; 11-seventh resistor; 12-first filter capacitor; 13-first diode; 14-second diode; 15-fourth power supply terminal; 16-eighth resistor; 17-second filter capacitor. DETAILED DESCRIPTION

[0050] At present, the main purpose of the current sampling circuit of the motor of new energy vehicles is to detect the working current of the motor in real time, so as to facilitate the precise control of the control system and the implementation of protection measures. Hall current sensor modules are widely used for sampling large currents of new energy motors. Usually, the external specifications of the current sensor module are output current gain G, which is usually at the millivolt mV level. The sampling circuit is designed to be built by operational amplifiers and resistors. If it is simply sampled, error sources such as power supply, resistors, and operational amplifiers will be introduced, which will deviate from the actual current sensor output voltage value, and the deviation determines the current sampling accuracy.

[0051] Therefore, in order to improve the accuracy of current sampling, the present application provides a current sampling bias calibration circuit and a vehicle motor detection device. While setting the sampling circuit, a calibration circuit is further set in parallel corresponding to the circuit structure of the sampling circuit. After the voltage of the fixed first voltage end is input to the input end of the calibration circuit, the calibration circuit outputs a cumulative feedback value with error to the calibration feedback port, so that the microcontroller unit adjusts the feedback value of the sampling circuit output end based on the feedback value of the calibration circuit input end and the accumulated error, determines the sampling value of the sampling circuit input end, reduces the error caused by factors such as components in the sampling circuit and ambient temperature, and improves the sampling accuracy.

[0052] In addition, in order to ensure that the feedback value output to the microcontroller unit is within the voltage acquisition range of the analog-to-digital converter, the present application also sets up a corresponding voltage amplitude attenuation module to avoid the situation where the feedback value exceeds the voltage acquisition range of the analog-to-digital converter, resulting in failure of feedback or abnormal feedback.

[0053] In order to enable those skilled in the art to better understand the solution of the utility model, the technical solution in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is only a part of the embodiment of the utility model, not all of the embodiments. Based on the embodiment of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0054] See also Figure 1 The structural schematic diagram of a current sampling bias calibration circuit shown in the figure, the present application provides a current sampling bias calibration circuit, including a sampling circuit and a calibration circuit corresponding to the sampling circuit;

[0055] The input end of the sampling circuit collects the sampled value of the target phase electricity through the current sensor, and the output end of the sampling circuit is connected to the sampling feedback port of the micro control unit; the input end of the calibration circuit is connected to the first voltage end, and the output end of the calibration circuit is connected to the calibration feedback port of the micro control unit, and the voltage of the first voltage end is the output voltage of the current sensor when there is no current;

[0056] When the output voltage of the current sensor when there is no current is greater than a first threshold value, the calibration circuit and the sampling circuit are both provided with a voltage amplitude attenuation module for adjusting the feedback value output to the microcontroller unit within the voltage acquisition range of the analog-to-digital converter corresponding to the microcontroller unit, and the first threshold value is determined according to the voltage acquisition range of the analog-to-digital converter.

[0057] The above-mentioned first threshold value can be half of the maximum value of the voltage acquisition range of the analog-to-digital converter, or it can be a value in a preset range value based on half of the maximum value of the voltage acquisition range of the analog-to-digital converter, and the value in the preset range is less than or equal to half of the maximum value of the voltage acquisition range of the analog-to-digital converter.

[0058] The current sensor is connected to collect the electrical parameters of the corresponding target phase electricity and output the sampling value to the sampling circuit. The sampling value is processed by the modules of the sampling circuit, such as the operational amplifier and the filter module, and then the feedback value is output to the micro control unit. The feedback value needs to be within the voltage acquisition range of the analog-to-digital converter (the analog-to-digital converter can be an analog-to-digital converter ADC module integrated in the micro control unit) corresponding to the micro control unit, so that the analog-to-digital converter can convert the analog signal of the feedback value into a digital signal. Similarly, the input end of the calibration circuit inputs the voltage of the fixed first voltage end (the output voltage of the current sensor when there is no current), and the output end of the calibration circuit also outputs the feedback value to the micro control unit. Since the circuit structure of the calibration circuit corresponds to the sampling circuit setting, the cumulative error in the circuit determined by the calibration circuit (including errors caused by components such as power supply, resistors and temperature) can be used as a reference for the cumulative error of the sampling circuit. Then, based on the accumulated error of the feedback value of the calibration circuit, the feedback value of the sampling circuit is adjusted to determine the sampling value of the sampling circuit, and the errors caused by the calibration components and ambient temperature are calibrated to improve the sampling accuracy.

[0059] Optionally, the calibration circuit is configured to correspond to the sampling circuit, and components of the sampling circuit that have a smaller impact on the cumulative error can be omitted in the design of the calibration circuit.

[0060] In addition, according to the corresponding relationship between the output voltage of the current sensor when there is no current and the voltage acquisition range of the analog-to-digital converter, when it is judged that the feedback value output by the sampling circuit and the calibration circuit to the microcontroller unit exceeds the voltage acquisition range, a voltage amplitude attenuation module can be set in both the sampling circuit and the calibration circuit, so that when the sampling value and the voltage value of the first voltage end exceed the voltage acquisition range of the analog-to-digital converter, the sampling value can also be determined, which can be applicable to microcontroller systems with different voltage amplitude platforms.

[0061] In one possible implementation, see Figure 1 The sampling circuit includes a sampling operational amplifier and a first processing module connected to the output end of the sampling operational amplifier, and the output end of the first processing module is connected to the sampling feedback port; the calibration circuit includes a calibration operational amplifier and a second processing module connected to the output end of the calibration operational amplifier, and the output end of the second processing module is connected to the calibration feedback port; the first processing module and the second processing module both include a filtering submodule;

[0062] The positive input terminal of the sampling operational amplifier is connected to the input terminal of the sampling circuit, and the positive input terminal of the calibration operational amplifier is connected to the first voltage terminal. The sampling operational amplifier and the calibration operational amplifier are both provided with a gain adjustment resistor between their respective reverse input terminals and output terminals. Optionally, the gain adjustment resistor can also be connected in parallel with a capacitor.

[0063] The filter submodule of the first processing module and the filter submodule of the second processing module include the same components and the same specifications of the components.

[0064] In the case that the output voltage of the current sensor when there is no current is greater than a first threshold, the sampling operational amplifier and the calibration operational amplifier are both provided with the voltage amplitude attenuation module.

[0065] In a case where the output voltage of the current sensor when there is no current is less than or equal to the first threshold, neither the sampling operational amplifier nor the calibration operational amplifier is provided with the voltage amplitude attenuation module.

[0066] In a possible implementation, when the output voltage of the current sensor when there is no current is greater than half of the maximum value of the voltage acquisition range of the analog-to-digital converter, the sampling operational amplifier and the calibration operational amplifier are both provided with a voltage amplitude attenuation module.

[0067] When the output voltage of the current sensor when there is no current is not greater than half of the maximum value of the voltage acquisition range of the analog-to-digital converter, the sampling operational amplifier and the calibration operational amplifier may not be provided with the voltage amplitude attenuation module.

[0068] Since the voltage of the target phase electricity collected by the current sensor has positive and negative fluctuations, the sampling value collected and output by the current sensor will fluctuate up and down based on the output voltage of the current sensor when there is no current. The output voltage of the current sensor when there is no current is greater than half of the maximum value of the voltage acquisition range of the analog-to-digital converter. There may be sampling values ​​that exceed the voltage acquisition range of the analog-to-digital converter, affecting the determination of subsequent sampling values. Therefore, a voltage amplitude attenuation module is set. The specific setting method can be:

[0069] The voltage amplitude attenuation module includes a common bias voltage input submodule and a reverse bias voltage input submodule; the common input terminal of the calibration operational amplifier and the common input terminal of the sampling operational amplifier are both provided with a common bias voltage input submodule, and the reverse input terminal of the calibration operational amplifier and the reverse input terminal of the sampling operational amplifier are both provided with a reverse bias voltage submodule; the voltage output by the reverse bias voltage submodule to the corresponding reverse input terminal is the same as the output voltage of the current sensor when there is no current.

[0070] The voltage output by the reverse bias voltage submodule to the corresponding reverse input terminal is the same as the output voltage of the current sensor when there is no current. Through the operational amplifier, the output voltage value of the current sensor input at the same direction input terminal when there is no current can be offset, and the bias voltage input is performed through the same direction bias voltage input submodule to adjust the feedback value finally output to the micro control unit within the voltage acquisition range of the analog-to-digital converter.

[0071] In a possible implementation, the specific circuit structure of the common bias voltage input submodule and the reverse bias voltage submodule may be:

[0072] The same-direction bias voltage input submodule includes a first resistor and a first power supply terminal, the voltage of the first power supply terminal is the first threshold, the first power supply terminal is connected to the first end of the first resistor, and the second end of the first resistor is connected to the same-direction input terminal corresponding to the same-direction bias voltage input submodule; in the sampling circuit, the second end of the first resistor is also connected to the first end of the second resistor, and the second end of the second resistor is the input terminal of the sampling circuit; in the calibration circuit, the second end of the first resistor is also connected to the first voltage terminal, the first voltage terminal is connected to the first end of the third resistor, the second end of the third resistor is connected to the second power supply terminal, the first voltage terminal is also connected to the first end of the fourth resistor, and the second end of the fourth resistor is grounded.

[0073] The reverse bias voltage submodule includes a fifth resistor and a sixth resistor, wherein the first end of the fifth resistor and the first end of the sixth resistor are both connected to the reverse input end corresponding to the reverse bias voltage submodule, the second end of the fifth resistor is connected to the third power supply end, and the second end of the sixth resistor is grounded.

[0074] In one example, the maximum value of the voltage acquisition range is set to 3.3V, and the output voltage of the current sensor is 2.5V when there is no current. Since 2.5V exceeds 1.65V (half of 3.3V), it is necessary to set a same-direction bias voltage submodule at the same-direction input end and a reverse bias voltage submodule at the reverse input end.

[0075] For details, see Figure 2A schematic diagram of the structure of a sampling circuit in which a sampling operational amplifier is provided with a common bias voltage submodule and a reverse bias voltage submodule, since the voltage output by the reverse bias voltage submodule to the corresponding reverse input terminal is the same as the output voltage of the current sensor when there is no current, the output of the operational amplifier finally offsets the voltage value output by the current sensor when there is no current, and the first power supply terminal is introduced to the input terminal of the common bias operational amplifier of the sampling circuit to provide a bias voltage (1.65V), therefore, the sampling value input to the input terminal of the sampling circuit is based on the bias voltage (1.65V) input provided by the first power supply terminal, as well as the first resistor and the second resistor, and the feedback value of the sampling value finally output to the micro control unit is a value accumulated on the basis of 1.65±sampling value×(first resistor / second resistor) by the sampling circuit error.

[0076] Similarly, see Figure 3 A structural schematic diagram of a calibration circuit in which a calibration operational amplifier is provided with a common bias voltage submodule and a reverse bias voltage submodule, wherein the common input terminal of the calibration operational amplifier of the calibration circuit is also provided to provide a bias voltage input corresponding to the sampling circuit, that is, a first power supply terminal (1.65V) and a first resistor are provided, and a reverse bias voltage submodule is provided at the reverse input terminal corresponding to the sampling circuit. Since the voltage of the reverse bias voltage submodule to the corresponding reverse input terminal is the same as the output voltage of the current sensor when there is no current, and the input terminal voltage of the calibration circuit is the output voltage (2.5V) of the current sensor when there is no current, the input voltage is offset by the operational amplifier, so that the calibration circuit accumulates the value of the calibration circuit error on the basis of the feedback value of 1.65V output by the control unit. Since the calibration circuit is provided corresponding to the sampling circuit, the sampling value of the sampling circuit can be calibrated and determined based on the accumulated error of the feedback value of the calibration circuit, thereby improving the sampling accuracy.

[0077] The voltage at the above-mentioned first voltage terminal and the voltage of the reverse bias voltage submodule to the corresponding reverse input terminal are both the output voltage (2.5V) of the current sensor when there is no current. Therefore, the required voltage at the first voltage terminal is formed by voltage division based on the second power supply terminal and the third resistor and the fourth resistor, and the required voltage at the reverse input terminal is formed by voltage division based on the third power supply terminal and the fifth resistor and the sixth resistor.

[0078] Furthermore, in a possible implementation, the second power supply terminal and the third power supply terminal are the same power supply terminal, the resistance value of the third resistor is the same as the resistance value of the fourth resistor, the resistance value of the fifth resistor is the same as the resistance value of the sixth resistor, and the voltage of the second power supply terminal is twice the output voltage of the current sensor when there is no current, that is, the voltage of the second power supply terminal and the third power supply terminal can be the same power supply terminal, providing a voltage of 5V. When the resistance value of the third resistor is the same as that of the fourth resistor, the voltage of the first voltage terminal is 2.5V. Similarly, when the resistance value of the fifth resistor is the same as that of the sixth resistor, the voltage of the reverse input terminal is also 2.5V.

[0079] In another example, the maximum value of the voltage acquisition range is set to 5V, and the output voltage of the current sensor is 2.5V when there is no current. Since 2.5V is equal to half of 5V, there is no need to set a common bias voltage submodule at the common input end, nor is there a reverse bias voltage submodule at the reverse input end.

[0080] Based on the above embodiment, in a possible implementation, the first processing module of the sampling circuit mentioned above may include a first voltage clamping module in addition to the filtering submodule; similarly, the second processing module of the calibration circuit may include a second voltage clamping module in addition to the filtering submodule. The circuit structure of the first processing module may be the same as the circuit structure of the second processing module. For details, see Figure 4 A structural schematic diagram of a sampling circuit is shown.

[0081] The filtering submodule of the first processing module includes a seventh resistor and a first filtering capacitor, the output end of the sampling operational amplifier is connected to the first end of the seventh resistor, the second end of the seventh resistor is connected to the first node of the first voltage clamping module, the first node of the first voltage clamping module is connected to the first end of the first filtering capacitor, the first node of the first voltage clamping module is also connected to the output end of the sampling circuit, and the second end of the first filtering capacitor is grounded; the first voltage clamping module includes a first diode and a second diode, the positive electrode of the first diode and the negative electrode of the second diode are connected to the first node of the first voltage clamping module, the negative electrode of the first diode is connected to the fourth power supply end, the positive electrode of the second diode is grounded, and the voltage of the fourth power supply end is the maximum value of the voltage acquisition range of the analog-to-digital converter;

[0082] The filtering submodule of the second processing module includes an eighth resistor and a second filtering capacitor, the output end of the calibration operational amplifier is connected to the first end of the eighth resistor, the second end of the eighth resistor is connected to the first node of the second voltage clamping module, the first node of the second voltage clamping module is connected to the first end of the second filtering capacitor, the first node of the second voltage clamping module is also connected to the output end of the calibration circuit, and the second end of the second filtering capacitor is grounded; the second voltage clamping module includes a third diode and a fourth diode, the anode of the third diode and the cathode of the fourth diode are connected to the first node of the second voltage clamping module, the cathode of the third diode is connected to the fourth power supply end, the anode of the fourth diode is grounded, and the voltage of the fourth power supply end is the maximum value of the voltage acquisition range of the analog-to-digital converter.

[0083] In another possible implementation, the circuit structure of the first processing module of the sampling circuit can still adopt Figure 4 However, since the voltage clamping module has little effect on the circuit cumulative error, the second voltage clamping module in the calibration circuit can be omitted. Figure 5 A structural schematic diagram of a calibration circuit is shown, in which the second processing module of the calibration circuit only retains the filtering submodule, and the filtering submodule of the second processing module includes an eighth resistor and a second filtering capacitor, the output end of the calibration operational amplifier is connected to the first end of the eighth resistor, the second end of the eighth resistor is connected to the first end of the second filtering capacitor, the second end of the second filtering capacitor is grounded, and the second end of the eighth resistor is also connected to the output end of the calibration circuit.

[0084] Based on the above embodiment, the sampling circuit can sample a target phase electricity in the three-phase motor and calibrate it through the corresponding calibration circuit. Of course, multiple sampling circuits can also be set to sample multiple phase electricity in the three-phase motor. When it is necessary to determine the current information of the three phase electricity of the motor, on the one hand, two of the three phase electricity can be sampled through a sampling circuit respectively, and the current of the two phase electricity can be determined after calibrating the sampled values ​​of the two phase electricity through the calibration circuit, and the current information of another phase electricity that has not been sampled in the three phase electricity can be determined through the conversion relationship of the three-phase electricity of the motor.

[0085] Exemplarily, the three-phase electricity to be sampled may include three phases of electricity: A-phase electricity, B-phase electricity, and C-phase electricity. In this example, sampling circuits are respectively set for A-phase electricity and C-phase electricity, and a calibration circuit is set.

[0086] If the output voltage of the current sensor when there is no current is greater than half of the maximum value of the voltage acquisition range of the analog-to-digital converter, for example, a 3.3V platform microcontroller unit MCU system (such as C2000, STM32) is used, VDDA = reference voltage VREF = 3.3V, and the maximum value of the voltage acquisition range of the corresponding analog-to-digital converter is 3.3V. The output voltage of the current sensor when there is no current is set to 2.5V. Since 2.5V exceeds 1.65V (half of 3.3V), it is necessary to set a common bias voltage submodule at the common input end and a reverse bias voltage submodule at the reverse input end. For the specific circuit structure, see Figure 6 The diagram shows a structure of configuring two sampling circuits and one calibration circuit in a three-phase motor.

[0087] The sampling circuit input end of phase A obtains the sampling value U output by the current sensor corresponding to phase A. Ia , through the operational amplifier UIA (the same-direction input terminal is provided with a voltage source of 1.65V bias voltage, a same-direction bias voltage submodule composed of resistors R1 and R2; the reverse input terminal is provided with a reverse bias voltage submodule which is powered by a 5V power supply terminal and forms a 2.5V voltage output terminal through a voltage division of resistors R5 and R6 with the same resistance value; a resistor R7 is provided between the output terminal and the reverse input terminal of UIA) and the first processing module of phase A (including a filtering submodule composed of a resistor R3 and a capacitor C3 and a first clamping voltage submodule composed of two diodes D1), the feedback value U is output to the port provided at the output terminal of the sampling circuit corresponding to the phase A electricity of the micro control unit. Ia_MCU .

[0088] The sampling circuit input end of the C phase electricity obtains the sampling value U output by the current sensor corresponding to the C phase electricity setting Ic , through the operational amplifier UIC (the same-direction input terminal is provided with a voltage source of 1.65V bias voltage, a same-direction bias voltage submodule composed of resistors R8 and R9; the reverse input terminal is provided with a reverse bias voltage submodule which is powered by a 5V power supply terminal and forms a 2.5V voltage output terminal through a voltage division of resistors R12 and R13 with the same resistance value; a resistor R14 is provided between the output terminal and the reverse input terminal of UIC) and the first processing module of phase C (including a filtering submodule composed of a resistor R10 and a capacitor C7 and a first clamping voltage submodule composed of two diodes D3), the feedback value U is output to the port provided at the output terminal of the sampling circuit corresponding to the phase C of the micro control unit. Ic_MCU .

[0089] The input end of the calibration circuit is connected to a 2.5V voltage end (powered by a 5V power supply end and divided by resistors R15 and R19 of the same resistance value to form a 2.5V voltage end), and outputs a reference feedback value U corresponding to 1.65V to a calibration port corresponding to the microcontroller unit through an operational amplifier UID (a voltage source with a 1.65V bias voltage and a resistor R16 are set at the same input end; a reverse input end is set to be powered by a 5V power supply end and divided by resistors R18 and R20 of the same resistance value to form a reverse bias voltage output end; a resistor R11 is set between the output end and the reverse input end of the UID) and a second processing module (including a filtering submodule composed of a resistor R17 and a capacitor C10). MCU_AD_I_BASE .

[0090] If the output voltage of the current sensor when there is no current is not greater than half of the maximum value of the voltage acquisition range of the analog-to-digital converter, for example, a 5V microcontroller unit MCU system (such as Infineon ARIX platform SAK-TC275, SAK-TC387, etc.) is used, the maximum value of the voltage acquisition range of the corresponding analog-to-digital converter is 5V, and the output voltage of the current sensor when there is no current is set to 2.5V. Since 2.5V is equal to half of 5V, there is no need to set a common bias voltage submodule at the common input end, nor is there a need to set a reverse bias voltage submodule at the reverse input end. For the specific circuit structure, see Figure 7 Another structural schematic diagram of configuring two sampling circuits and one calibration circuit in a three-phase motor is shown.

[0091] The sampling circuit input end of phase A obtains the sampling value U output by the current sensor corresponding to phase A. Ia , connected to the same-direction input terminal of the operational amplifier UIA through the resistor R2, a resistor R7 is set between the output terminal and the reverse input terminal of UIA, the output terminal of the operational amplifier UIA is connected to the first processing module of phase A (including a filter submodule composed of a resistor R3 and a capacitor C3 and a first clamping voltage submodule composed of two diodes D1), and the feedback value U is output to the port set at the output terminal of the sampling circuit of the micro control unit corresponding to phase A Ia_MCU .

[0092] The sampling circuit input end of the C phase electricity obtains the sampling value U output by the current sensor corresponding to the C phase electricity setting Ic , connected to the same-direction input terminal of the operational amplifier UIC through the resistor R9, a resistor R14 is set between the output terminal and the reverse input terminal of UIC, the output terminal of the operational amplifier UIC is connected to the first processing module of phase C (including a filter submodule composed of a resistor R10 and a capacitor C7 and a first clamping voltage submodule composed of two diodes D3), and the feedback value U is output to the port set at the output terminal of the sampling circuit of the micro control unit corresponding to the phase C electricityIc_MCU .

[0093] The same-direction input terminal of the operational amplifier UID of the calibration circuit is connected to a 2.5V voltage terminal (powered by a 5V power supply terminal and divided by resistors R15 and R19 of the same resistance value to form a 2.5V voltage terminal), a resistor R11 is set between the output terminal and the reverse input terminal of the operational amplifier UID, and the output terminal of the operational amplifier UID is connected to the second processing module (including a filtering submodule composed of a resistor R17 and a capacitor C10), and then outputs a reference feedback value U to the calibration port corresponding to the micro control unit. MCU_AD_I_BASE .

[0094] For example, based on Figure 6 and Figure 7 For example, a sampling circuit and a calibration circuit can be respectively set for phase A, phase B and phase C, and each phase can be sampled independently to further improve the sampling accuracy.

[0095] If the output voltage of the current sensor when there is no current is greater than half of the maximum value of the voltage acquisition range of the analog-to-digital converter, it can be based on Figure 6 In the three-phase motor shown in the figure, a sampling circuit is set for each phase A and phase C, and a calibration circuit is used to adjust the feedback value of the sampling circuit, and a sampling circuit is added for the phase B. For details, please refer to Figure 8 The diagram shown is a structural diagram of respectively setting sampling circuits for three phases of a three-phase motor.

[0096] The sampling circuit input end of the B phase electricity obtains the sampling value U output by the current sensor corresponding to the B phase electricity setting Ib , through the operational amplifier UIB (the same-direction input terminal is provided with a voltage source of 1.65V bias voltage, a same-direction bias voltage submodule composed of resistors R21 and R22; the reverse input terminal is provided with a reverse bias voltage submodule which is powered by a 5V power supply terminal and forms a 2.5V voltage output terminal through a voltage division of resistors R23 and R24 with the same resistance value; a resistor R25 is provided between the output terminal and the reverse input terminal of UIB) and the first processing module of phase B (including a filtering submodule composed of a resistor R26 and a capacitor C4 and a first clamping voltage submodule composed of two diodes D2), the feedback value U is output to the port provided at the output terminal of the sampling circuit corresponding to the phase B electricity of the micro control unit. Ib_MCU .

[0097] It should be noted that in the present application, the specifications of the resistors and capacitors at the corresponding circuit structure positions in the sampling circuit and the calibration circuit are the same, the specifications of the operational amplifiers are the same, and the specifications of the resistors and capacitors at the corresponding circuit structure positions in multiple sampling circuits are the same, and the specifications of the operational amplifiers are the same.

[0098] Similarly, if the output voltage of the current sensor when there is no current is not greater than half of the maximum value of the voltage acquisition range of the analog-to-digital converter, it can be based on Figure 7 In the corresponding three-phase motor shown in the figure, a sampling circuit is set for the A phase and the C phase respectively, and an additional sampling circuit is set for the B phase.

[0099] The sampling circuit input end of the B phase electricity obtains the sampling value U output by the current sensor corresponding to the B phase electricity setting Ib , the same-direction input terminal of the operational amplifier UIB is connected through a resistor with the same resistance value as the resistor R2 and the resistor R9, a resistor with the same resistance value as the resistor R7 and the resistor R14 is set between the output terminal and the reverse input terminal of UIB, the output terminal of the operational amplifier UIB is connected to the first processing module of phase B (including a filter submodule composed of a resistor with the same resistance value as the resistor R3 and R10 and a capacitor with the same specification as the capacitor C3 and C7, and a first clamping voltage submodule composed of two diodes D2 (with the same specification as the diode D1 and D3)), and the feedback value U is output to the port set at the output terminal of the sampling circuit of the micro control unit corresponding to the phase C electricity Ic_MCU .

[0100] Based on the above embodiments, the present application also provides a vehicle motor detection device, which adopts a current sampling bias calibration circuit described in any of the above embodiments.

[0101] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0102] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A current sampling bias calibration circuit, characterized in that: It includes a sampling circuit and a calibration circuit arranged corresponding to the sampling circuit; The input end of the sampling circuit collects the sampled value of the target phase electricity through the current sensor, and the output end of the sampling circuit is connected to the sampling feedback port of the micro control unit; The input end of the calibration circuit is connected to the first voltage end, the output end of the calibration circuit is connected to the calibration feedback port of the micro control unit, and the voltage of the first voltage end is the output voltage of the current sensor when there is no current; When the output voltage of the current sensor when there is no current is greater than a first threshold value, the calibration circuit and the sampling circuit are both provided with a voltage amplitude attenuation module for adjusting the feedback value output to the microcontroller unit within the voltage acquisition range of the analog-to-digital converter corresponding to the microcontroller unit, and the first threshold value is determined according to the voltage acquisition range of the analog-to-digital converter.

2. The circuit according to claim 1, characterized in that The sampling circuit comprises a sampling operational amplifier and a first processing module connected to the output end of the sampling operational amplifier, wherein the output end of the first processing module is connected to the sampling feedback port; The calibration circuit comprises a calibration operational amplifier and a second processing module connected to the output end of the calibration operational amplifier, the output end of the second processing module is connected to the calibration feedback port; the first processing module and the second processing module both comprise a filtering submodule; In the case that the output voltage of the current sensor when there is no current is greater than a first threshold, the sampling operational amplifier and the calibration operational amplifier are both provided with the voltage amplitude attenuation module.

3. The circuit according to claim 2, characterized in that The voltage amplitude attenuation module includes a common bias voltage input submodule and a reverse bias voltage input submodule; The same-direction input terminal of the calibration operational amplifier and the same-direction input terminal of the sampling operational amplifier are both provided with a same-direction bias voltage input submodule, The reverse input terminal of the calibration operational amplifier and the reverse input terminal of the sampling operational amplifier are both provided with a reverse bias voltage submodule; The voltage output by the reverse bias voltage submodule to the corresponding reverse input terminal is the same as the output voltage of the current sensor when there is no current.

4. The circuit according to claim 3, characterized in that The same-direction bias voltage input submodule comprises a first resistor and a first power supply end, the voltage of the first power supply end is the first threshold, the first power supply end is connected to the first end of the first resistor, and the second end of the first resistor is connected to the same-direction input end corresponding to the same-direction bias voltage input submodule; In the sampling circuit, the second end of the first resistor is also connected to the first end of the second resistor, and the second end of the second resistor is the input end of the sampling circuit; In the calibration circuit, the second end of the first resistor is also connected to the first voltage end, the first voltage end is connected to the first end of the third resistor, the second end of the third resistor is connected to the second power supply end, the first voltage end is also connected to the first end of the fourth resistor, and the second end of the fourth resistor is grounded.

5. The circuit according to claim 4, characterized in that The reverse bias voltage submodule includes a fifth resistor and a sixth resistor, wherein the first end of the fifth resistor and the first end of the sixth resistor are both connected to the reverse input end corresponding to the reverse bias voltage submodule, the second end of the fifth resistor is connected to the third power supply end, and the second end of the sixth resistor is grounded.

6. The circuit according to claim 5, characterized in that The second power supply terminal and the third power supply terminal are the same power supply terminal, the resistance value of the third resistor is the same as the resistance value of the fourth resistor, the resistance value of the fifth resistor is the same as the resistance value of the sixth resistor, and the voltage of the second power supply terminal is twice the output voltage of the current sensor when there is no current.

7. The circuit according to claim 2, characterized in that The first processing module further includes a first voltage clamping module, and the second processing module further includes a second voltage clamping module; The filtering submodule of the first processing module includes a seventh resistor and a first filtering capacitor, the output end of the sampling operational amplifier is connected to the first end of the seventh resistor, the second end of the seventh resistor is connected to the first node of the first voltage clamping module, the first node of the first voltage clamping module is connected to the first end of the first filtering capacitor, the first node of the first voltage clamping module is also connected to the output end of the sampling circuit, and the second end of the first filtering capacitor is grounded; the first voltage clamping module includes a first diode and a second diode, the positive electrode of the first diode and the negative electrode of the second diode are connected to the first node of the first voltage clamping module, the negative electrode of the first diode is connected to the fourth power supply end, the positive electrode of the second diode is grounded, and the voltage of the fourth power supply end is the maximum value of the voltage acquisition range of the analog-to-digital converter; The filtering submodule of the second processing module includes an eighth resistor and a second filtering capacitor, the output end of the calibration operational amplifier is connected to the first end of the eighth resistor, the second end of the eighth resistor is connected to the first node of the second voltage clamping module, the first node of the second voltage clamping module is connected to the first end of the second filtering capacitor, the first node of the second voltage clamping module is also connected to the output end of the calibration circuit, and the second end of the second filtering capacitor is grounded; the second voltage clamping module includes a third diode and a fourth diode, the anode of the third diode and the cathode of the fourth diode are connected to the first node of the second voltage clamping module, the cathode of the third diode is connected to the fourth power supply end, the anode of the fourth diode is grounded, and the voltage of the fourth power supply end is the maximum value of the voltage acquisition range of the analog-to-digital converter.

8. The circuit according to claim 2, characterized in that The first processing module also includes a first voltage clamping module; The filtering submodule of the first processing module includes a seventh resistor and a first filtering capacitor, the output end of the sampling operational amplifier is connected to the first end of the seventh resistor, the second end of the seventh resistor is connected to the first node of the first voltage clamping module, the first node of the first voltage clamping module is connected to the first end of the first filtering capacitor, the first node of the first voltage clamping module is also connected to the output end of the sampling circuit, and the second end of the first filtering capacitor is grounded; the first voltage clamping module includes a first diode and a second diode, the positive electrode of the first diode and the negative electrode of the second diode are connected to the first node of the first voltage clamping module, the negative electrode of the first diode is connected to the fourth power supply end, the positive electrode of the second diode is grounded, and the voltage of the fourth power supply end is the maximum value of the voltage acquisition range of the analog-to-digital converter; The filtering submodule of the second processing module includes an eighth resistor and a second filtering capacitor. The output end of the calibration operational amplifier is connected to the first end of the eighth resistor, the second end of the eighth resistor is connected to the first end of the second filtering capacitor, the second end of the second filtering capacitor is grounded, and the second end of the eighth resistor is also connected to the output end of the calibration circuit.

9. The circuit according to any one of claims 1 to 8, characterized in that: The circuit includes a plurality of sampling circuits; The input end of the first sampling circuit inputs the sampling value of the first phase electricity of the motor to be sampled, and the output end of the first sampling circuit is connected to the first sampling feedback port of the micro control unit; The input end of the second sampling circuit inputs the sampling value of the second phase electricity of the motor to be sampled, and the output end of the second sampling circuit is connected to the second sampling feedback port of the micro control unit; and / or, The input end of the first sampling circuit inputs the sampling value of the first phase electricity of the motor to be sampled, and the output end of the first sampling circuit is connected to the first sampling feedback port of the micro control unit; The input end of the second sampling circuit inputs the sampling value of the second phase electricity of the motor to be sampled, and the output end of the second sampling circuit is connected to the second sampling feedback port of the micro control unit; The input end of the third sampling circuit inputs the sampling value of the third phase electricity of the motor to be sampled, and the output end of the third sampling circuit is connected to the third sampling feedback port of the micro control unit.

10. A vehicle motor detection device, characterized in that: A current sampling bias calibration circuit as described in any one of claims 1 to 9 is adopted.

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