Current sampling device and motor controller

Abstract

The invention relates to a current sampling device and a motor controller. The current sampling device comprises an isolation module, a conditioning module and a processing module. The input end of the isolation module is connected with the sampling output end of the current sensor, the output end of the isolation module is connected with the first input end of the conditioning module, the second input end of the conditioning module is connected with reference voltage, and the output end of the conditioning module is connected with the processing module; wherein the isolation module is used for isolating a bias voltage signal in an alternating current signal output by a sampling output end of the current sensor, and outputting the isolated alternating current signal; the conditioning module is used for converting a negative voltage in the isolated alternating current signal into a positive voltage by adopting a reference voltage and outputting the adjusted alternating current signal to the processing module; the processing module is used for determining a sampled current value according to the adjusted alternating current signal; therefore, the current sampling precision is improved.

Description

Technical Field

[0001] This application relates to the technical field of current sampling, and particularly to a current sampling device and a motor controller. Background Art

[0002] Current closed-loop control is one of the main closed-loop control methods in the field of motor drive. Current closed-loop control performs closed-loop operation based on the difference between the given current and the feedback actual current to eliminate the error between the actual current and the given current, so as to achieve the purpose of real-time tracking of the actual current by the given current. Among them, the actual current can be the actual phase current of the motor.

[0003] In the related art, the above-mentioned actual current can be sampled by a current sensor. Specifically, the output voltage of the current sensor Vout = I * G_th + Voff is used to calculate the sampled actual current I, where G_th represents the gain of the current sensor, Voff represents the offset voltage of the current sensor, and Voff is usually half of the supply voltage of the current sensor.

[0004] However, in practical applications, Voff is often affected by the structure of the current sensor itself and has a deviation, resulting in inaccurate Vout, and further resulting in inaccurate calculated actual current I, ultimately affecting motor drive. Summary of the Invention

[0005] Based on this, it is necessary to provide a current sampling device and a motor controller that improve the accuracy of current sampling.

[0006] In a first aspect, an embodiment of this application provides a current sampling device, which includes an isolation module, a conditioning module, and a processing module; the input end of the isolation module is connected to the sampling output end of the current sensor, the output end of the isolation module is connected to the first input end of the conditioning module, the second input end of the conditioning module accesses a reference voltage, and the output end of the conditioning module is connected to the processing module; where

[0007] the isolation module is used to isolate the offset voltage signal in the AC signal output by the sampling output end of the current sensor and output the isolated AC signal;

[0008] the conditioning module is used to convert the negative voltage in the isolated AC signal into a positive voltage by using the reference voltage and output the adjusted AC signal to the processing module;

[0009] the processing module is used to determine the sampled current value according to the adjusted AC signal.

[0010] In one of the embodiments, the isolation module includes a capacitor unit;

[0011] The first end of the capacitor unit is connected to the sampling output end of the current sensor, and the second end of the capacitor unit is connected to the first input end of the conditioning module;

[0012] The equivalent capacitance value of the capacitor unit is adapted to the operating frequency of the current sensor.

[0013] In one embodiment, the conditioning module includes a first resistor unit, a second resistor unit, a first filter unit, and an operational amplifier unit;

[0014] The first end of the first resistor unit is connected to the output end of the isolation module, and the second end of the first resistor unit is connected to the first end of the first filter unit;

[0015] The first end of the first filter unit is connected to the first input end of the operational amplifier unit, and the second end of the first filter unit is connected to the reference voltage;

[0016] The first end of the second resistor unit is connected to the second input end of the operational amplifier unit, and the second end of the second resistor unit is connected to the output end of the operational amplifier unit;

[0017] The output end of the operational amplifier unit is connected to the processing module;

[0018] Wherein, the conditioning module is further configured to adjust the amplitude of the isolated AC signal by using a gain coefficient, and the gain coefficient is determined according to the ratio of the equivalent resistance value of the second resistor unit to the equivalent resistance value of the first resistor unit.

[0019] In one embodiment, the first resistor unit and the second resistor unit satisfy the following conditions:

[0020] When the supply voltage of the processing module is equal to the supply voltage of the current sensor, the ratio of the equivalent resistance value of the second resistor unit to the equivalent resistance value of the first resistor unit is equal to 1;

[0021] When the supply voltage of the processing module is less than the supply voltage of the current sensor, the ratio of the equivalent resistance value of the second resistor unit to the equivalent resistance value of the first resistor unit is greater than zero and less than 1.

[0022] In one embodiment, the first filter unit includes a first filter resistor and a first filter capacitor;

[0023] The first end of the first filter resistor is connected to the first input end of the operational amplifier unit, the first end of the first filter resistor is connected to the second end of the first resistor unit, and the second end of the first filter resistor is connected to the reference voltage;

[0024] The first end of the first filter capacitor is connected to the first end of the first filter resistor, and the second end of the first filter capacitor is connected to the second end of the first filter resistor.

[0025] In one embodiment, the conditioning module further includes a second filtering unit;

[0026] The first end of the second filtering unit is connected to the second input end of the operational amplifier unit, and the second end of the second filtering unit is connected to the output end of the operational amplifier unit; wherein, the second filtering unit is configured to filter the signal transmitted to the second input end of the operational amplifier unit.

[0027] In one embodiment, the conditioning module includes a third filtering unit;

[0028] The first end of the third filtering unit is connected to the output end of the isolation module, the first end of the third filtering unit is connected to the processing module, and the second end of the third filtering unit is connected to the reference voltage;

[0029] Wherein, the supply voltage of the processing module is equal to the supply voltage of the current sensor.

[0030] In one embodiment, the current sampling device further includes a fourth filtering unit;

[0031] The output end of the conditioning module is connected to the processing module through the fourth filtering unit, and the fourth filtering unit is connected to the reference ground; wherein, the fourth filtering unit is configured to filter the signal output from the output end of the conditioning module.

[0032] In one embodiment, the current sampling device further includes a sampling module; the sampling module is connected to the reference voltage to sample the reference voltage and output a sampling voltage;

[0033] The first input end of the processing module is connected to the output end of the conditioning module, and the second input end of the processing module is connected to the output end of the sampling module; the processing module is configured to:

[0034] Obtain a first sampling voltage received by the second input end of the processing module at a reference moment, and obtain a second sampling voltage received by the second input end of the processing module at the current moment;

[0035] Obtain the absolute value of the difference between the first sampling voltage and the second sampling voltage;

[0036] When the second sampled voltage is less than the first sampled voltage, the adjusted AC signal output by the conditioning module at the current moment is superimposed on the absolute value of the difference, and the sampled current value is determined according to the superimposed signal;

[0037] When the second sampled voltage is greater than the first sampled voltage, the adjusted AC signal output by the conditioning module at the current moment is subtracted from the absolute value of the difference, and the sampled current value is determined according to the subtracted signal.

[0038] In one embodiment, the processing module is further configured to:

[0039] Compare the adjusted AC signal output by the conditioning module at the current moment with a preset voltage range. If the adjusted AC signal output by the conditioning module at the current moment exceeds the preset voltage range, an over-current sampling fault signal is output; wherein, the preset voltage range is determined according to the first sampled voltage.

[0040] In a second aspect, an embodiment of the present application provides an electric control product, which includes a current sensor and the current sampling device as described in the first aspect.

[0041] In the above current sampling device and motor controller, by providing an isolation module and a conditioning module, wherein the isolation module isolates the bias voltage signal in the AC signal output from the sampling output terminal of the current sensor and outputs the isolated AC signal. The bias voltage signal is the bias voltage signal of the current sensor, and the isolated AC signal no longer involves this bias voltage signal; then, the conditioning module adjusts the symmetry axis of the isolated AC signal with a reference voltage and outputs the adjusted AC signal. The adjusted AC signal no longer contains negative voltage signals but is all positive voltage signals, so that the adjusted AC signal can be received and processed by the processing module to determine the sampled current value.

[0042] It can be seen that in the technical solution of the embodiment of the present application, during the process of determining the sampled current value, the bias voltage signal of the current sensor is physically isolated, so that the sampled current value is determined according to the AC signal that does not involve the bias voltage signal of the current sensor, making the determination of the sampled current value not affected by the bias voltage signal of the current sensor. Even if the bias voltage signal of the current sensor has deviations or drifts, it will not affect the determination of the sampled current value, thereby improving the accuracy of the sampled current value, that is, the embodiment of the present application improves the current sampling accuracy. Description of the Drawings

[0043] To more clearly illustrate the technical solutions in the embodiments of the present application or in the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0044] Figure 1 It is one of the schematic structural diagrams of the current sampling device in an embodiment;

[0045] Figure 2(a) is the waveform diagram of the AC signal output by the current sensor;

[0046] Figure 2(b) is the waveform diagram of the isolated AC signal output by the isolation module;

[0047] Figure 2(c) is the waveform diagram of the adjusted AC signal output by the conditioning module;

[0048] Figure 3 It is one of the schematic structural diagrams of the isolation module in an embodiment;

[0049] Figure 4 It is the second schematic structural diagram of the isolation module in an embodiment;

[0050] Figure 5 It is the second schematic structural diagram of the current sampling device in an embodiment;

[0051] Figure 6 It is the third schematic structural diagram of the current sampling device in an embodiment;

[0052] Figure 7 It is the fourth schematic structural diagram of the current sampling device in an embodiment.

[0053] Explanation of reference numerals: 10 - current sampling device, 110 - isolation module, 1101 - capacitor unit, 120 - conditioning module, 130 - processing module, 140 - fourth filtering unit, 150 - sampling module, 1201 - first resistor unit, 1202 - second resistor unit, 1203 - first filtering unit, 1204 - operational amplifier unit, 1205 - second filtering unit, 1206 - third filtering unit, C1 - first capacitor, C2 - first filtering capacitor, C3 - second filtering capacitor, C4 - third filtering capacitor, R1 - first resistor, R2 - second resistor, R3 - first filtering resistor, R4 - second filtering resistor, Vref - reference voltage, U1 - operational amplifier. Detailed implementation manners

[0054] To facilitate the understanding of the present application, the present application will be described more comprehensively below with reference to the relevant drawings. Embodiments of the present application are shown in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the disclosure of the present application more thorough and comprehensive.

[0055] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which this application belongs. The terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0056] It can be understood that the terms "first", "second", etc. used in this application can be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish the first element from another element. For example, without departing from the scope of this application, the first resistor can be referred to as the second resistor, and similarly, the second resistor can be referred to as the first resistor. Both the first resistor and the second resistor are resistors, but they are not the same resistor.

[0057] It can be understood that for the "connection" in the following embodiments, if there is an electrical signal or data transfer between the connected circuits, modules, units, etc., it should be understood as "electrical connection", "communication connection", etc.

[0058] It can be understood that "at least one" means one or more, and "a plurality" means two or more. "At least a part of an element" means part or all of the element.

[0059] As used herein, the singular forms "a", "an" and "the" may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms "comprise / include" or "have" etc. specify the presence of the stated features, wholes, steps, operations, components, parts or combinations thereof, but do not exclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts or combinations thereof. At the same time, the term "and / or" used in this specification includes any and all combinations of the related listed items.

[0060] In an exemplary embodiment, referring to Figure 1 , a current sampling device 10 is provided, and the current sampling device 10 includes an isolation module 110, a conditioning module 120, and a processing module 130.

[0061] The input terminal of the isolation module 110 is connected to the sampling output terminal of the current sensor, and the output terminal of the isolation module 110 is connected to the first input terminal of the conditioning module 120; the isolation module 110 is used to isolate the bias voltage signal in the AC signal output from the sampling output terminal of the current sensor and output the isolated AC signal to the conditioning module 120.

[0062] Among them, the current sensor is, for example but not limited to, a single-ended current sensor or a differential current sensor. The bias voltage is a DC voltage, and the bias voltage of the current sensor is usually half of the supply voltage of the current sensor. Exemplarily, the supply voltage of the current sensor is +5V, and the bias voltage of the current sensor is (+5V)×0.5 = +2.5V. Due to the existence of the bias voltage of the current sensor, the AC signal carrying the sampled current value information output from the sampling output terminal of the current sensor contains a bias voltage signal.

[0063] The isolation module 110 is a hardware circuit, which can be composed of circuit components such as capacitors and resistors, for example. The isolation module 110 has the functional characteristic of "passing AC and blocking DC". Therefore, when the AC signal output from the sampling output terminal of the current sensor passes through the isolation module 110, the isolation module 110 will physically isolate the bias voltage signal in the AC signal, and the bias voltage signal in the AC signal will be blocked. Thus, the isolated AC signal output by the isolation module 110 no longer involves the bias voltage signal of the current sensor.

[0064] For example, if the output voltage Vout of the sampling output terminal of the current sensor is Vout = I*G_th + Voff, then the output of the isolation module 110 is Vout = I*G_th, and the isolated AC signal no longer involves the bias voltage signal of the current sensor. Among them, I represents the sampled current value, G_th represents the gain of the current sensor (the unit can be mV / A), and Voff represents the bias voltage of the current sensor. Also, for example, as shown in Figure 2(a), it is the waveform diagram of the AC signal output from the sampling output terminal of the current sensor, and the AC signal is symmetric about the axis of symmetry with the bias voltage Voff; after passing through the isolation module 110, as shown in Figure 2(b), it is the waveform diagram of the isolated AC signal output from the output terminal of the isolation module 110, the bias voltage signal is physically blocked, and the isolated AC signal no longer involves the bias voltage signal of the current sensor, and the isolated AC signal is symmetric about the horizontal axis of the coordinate axis.

[0065] The second input terminal of the conditioning module 120 is connected to the reference voltage Vref, and the output terminal of the conditioning module 120 is connected to the processing module 130; the conditioning module 120 is configured to adjust the symmetry axis of the isolated AC signal by using the reference voltage Vref to convert the negative voltage in the isolated AC signal into a positive voltage, and output the adjusted AC signal to the processing module 130; the processing module 130 is configured to determine the sampled current value according to the adjusted AC signal.

[0066] Among them, the reference voltage Vref and the bias voltage have the same characteristics, and the reference voltage Vref is also a DC voltage. Since it is the processing module 130 that receives and processes the adjusted AC signal output by the conditioning module 120, in practical applications, in order to make the adjusted AC signal adapt to the processing module 130, the reference voltage Vref can be half of the supply voltage of the processing module 130. Exemplarily, the supply voltage of the processing module 130 is +5V, and the reference voltage Vref is (+5V) × 0.5 = +2.5V; for another example, the supply voltage of the processing module 130 is +3.3V, and the reference voltage Vref is (+3.3V) × 0.5 = +1.65V.

[0067] The conditioning module 120 is a hardware circuit, for example, composed of circuit components such as capacitors, resistors, and amplifiers. Usually, for the reception and processing of the adjusted AC signal, the processing module 130 may have the same functional characteristics as a digital signal processor (DSP), and the processing module 130 may be but is not limited to a DSP. For example, the processing module 130 may include an analog-to-digital converter circuit (ADC), and the ADC is used as a peripheral device to receive the adjusted AC signal. Of course, the processing module 130 may also be an MCU (Microcontroller Unit, micro control unit).

[0068] Based on this, considering that the processing module 130 is more likely to receive and process the positive voltage in the alternating current signal and less likely to receive and process the negative voltage in the alternating current signal, the conditioning module 120 adjusts the axis of symmetry of the isolated alternating current signal by using the reference voltage Vref to convert the negative voltage in the isolated alternating current signal into a positive voltage and outputs the adjusted alternating current signal. For example, as shown in Fig. 2(c), it is the waveform diagram of the adjusted alternating current signal output by the output end of the conditioning module 120. The adjusted alternating current signal is symmetric about the reference voltage Vref. The adjusted alternating current signal no longer contains negative voltage signals but all positive voltage signals, so that the adjusted alternating current signal can be received and processed by the processing module 130 to determine the sampled current value. Also, for example, if the output of the isolation module 110 is Vout = I * G_th, then the output of the conditioning module 120 is Vout = (I * G_th) + Vref.

[0069] It can be seen that in the technical solution of the embodiment of the present application, during the process of determining the sampled current value, the bias voltage signal of the current sensor is physically isolated, so that the sampled current value is determined according to the alternating current signal that does not involve the bias voltage signal of the current sensor, making the determination of the sampled current value not affected by the bias voltage signal of the current sensor. Even if the bias voltage signal of the current sensor has deviations or drifts, it will not affect the determination of the sampled current value, thereby improving the accuracy of the sampled current value, that is, the embodiment of the present application improves the current sampling accuracy.

[0070] It can be understood that the influence of the current sensor structure itself on the bias voltage Voff includes various adverse effects brought by factors such as the noise of the current sensor itself, the hysteresis change of the magnetic core material inside the current sensor, the Hall element inside the current sensor, and the noise of the amplification factor of the operational amplifier inside the current sensor. In this regard, in practical applications, the bias voltage Voff cannot be calibrated externally. Therefore, the embodiment of the present application uses the isolation module 110 to isolate it to improve the influence of the deviation and drift of the bias voltage Voff on the current sampling accuracy and improve the current sampling accuracy.

[0071] The specific circuit structure and form of the isolation module 110 can be various, as long as it can achieve the function of isolating the bias voltage signal in the alternating current signal output by the sampling output end of the current sensor.

[0072] In an exemplary embodiment, referring to Figure 3 , the isolation module 110 includes a capacitor unit 1101; the first end of the capacitor unit 1101 is connected to the sampling output end of the current sensor, and the second end of the capacitor unit 1101 is connected to the first input end of the conditioning module 120.

[0073] Among them, the capacitor unit 1101 may include at least one capacitor. The connection relationship between multiple capacitors is arbitrary and will not be specifically limited herein. Based on the functional characteristic of a capacitor of "conducting alternating current and blocking direct current", the capacitor unit 1101 also has the functional characteristic of "conducting alternating current and blocking direct current". Therefore, when the alternating current signal output by the sampling output terminal of the current sensor passes through the isolation module 110, the capacitor unit 1101 will physically isolate the bias voltage signal in the alternating current signal, and the bias voltage signal in the alternating current signal will be blocked by the capacitor unit 1101. As a result, the isolated alternating current signal output by the isolation module 110 no longer involves the bias voltage signal of the current sensor. In addition, the equivalent capacitance value of the capacitor unit 1101 is adapted to the operating frequency of the current sensor to ensure reliable isolation of the bias voltage signal by the capacitor unit 1101. The isolation module 110 including the capacitor unit 1101 also makes the structure of the isolation module 110 simple, low in cost, and easy to implement.

[0074] In an exemplary embodiment, referring to Figure 4 , the capacitor unit 1101 includes a first capacitor C1; a first end of the first capacitor C1 is connected to the sampling output terminal of the current sensor, and a second end of the first capacitor C1 is connected to a first input terminal of the conditioning module 120. Among them, when the alternating current signal output by the sampling output terminal of the current sensor passes through the isolation module 110, the first capacitor C1 will physically isolate the bias voltage signal in the alternating current signal, and the bias voltage signal in the alternating current signal will be blocked by the first capacitor C1. As a result, the isolated alternating current signal output by the isolation module 110 no longer involves the bias voltage signal of the current sensor. The equivalent capacitance value of the first capacitor C1 is adapted to the operating frequency of the current sensor to ensure reliable isolation of the bias voltage signal by the first capacitor C1. The capacitor unit 1101 including the first capacitor C1 also makes the structure of the capacitor unit 1101 simple, low in cost, and easy to implement.

[0075] In an exemplary embodiment, referring to Figure 5 , the conditioning module 120 includes a first resistor unit 1201, a second resistor unit 1202, a first filtering unit 1203, and an operational amplifier unit 1204.

[0076] The first end of the first resistor unit 1201 is connected to the output end of the isolation module 110, and the second end of the first resistor unit 1201 is connected to the first end of the first filtering unit 1203; the first end of the first filtering unit 1203 is connected to the first input end of the operational amplifier unit 1204, and the second end of the first filtering unit 1203 is connected to the reference voltage Vref; the first end of the second resistor unit 1202 is connected to the second input end of the operational amplifier unit 1204, and the second end of the second resistor unit 1202 is connected to the output end of the operational amplifier unit 1204; the output end of the operational amplifier unit 1204 is connected to the processing module 130; based on this, the conditioning module 120 is further configured to apply a gain factor to the isolated AC signal to adjust the amplitude of the isolated AC signal; thus, the adjusted AC signal is a signal obtained by adjusting the amplitude of the isolated AC signal and adjusting the symmetry axis of the isolated AC signal using the reference voltage Vref; wherein, the gain factor is determined according to the ratio of the equivalent resistance value of the second resistor unit 1202 to the equivalent resistance value of the first resistor unit 1201. Exemplarily, the magnitude of the gain factor is equal to the ratio of the equivalent resistance value of the second resistor unit 1202 to the equivalent resistance value of the first resistor unit 1201.

[0077] Wherein, the first resistor unit 1201 includes at least one resistor. Exemplarily, refer to Figure 5 , the first resistor unit 1201 includes the first resistor R1. The second resistor unit 1202 includes at least one resistor. Exemplarily, refer to Figure 5 , the second resistor unit 1202 includes the second resistor R2. The ratio of the equivalent resistance value of the second resistor unit 1202 to the equivalent resistance value of the first resistor unit 1201 is the gain of the conditioning module 120, and the gain of the conditioning module 120 is used to adjust the amplitude of the isolated AC signal input to the conditioning module 120; when the ratio of the equivalent resistance value of the second resistor unit 1202 to the equivalent resistance value of the first resistor unit 1201 is equal to 1, the gain of the conditioning module 120 is 1, which can be understood as no adjustment to the amplitude of the isolated AC signal; when the ratio of the equivalent resistance value of the second resistor unit 1202 to the equivalent resistance value of the first resistor unit 1201 is greater than zero and less than 1, the gain of the conditioning module 120 is greater than zero and less than 1, which can be understood as reducing the amplitude of the isolated AC signal.

[0078] The operational amplifier unit 1204 may include at least one operational amplifier. Exemplarily, refer to Figure 5, the operational amplifier unit 1204 includes an operational amplifier U1. The first input terminal of the operational amplifier U1 serves as the first input terminal of the operational amplifier unit 1204, the second input terminal of the operational amplifier U1 serves as the second input terminal of the operational amplifier unit 1204, and the output terminal of the operational amplifier U1 serves as the output terminal of the operational amplifier unit 1204. Among them, exemplarily, the first input terminal of the operational amplifier U1 is the positive input terminal, and the second input terminal of the operational amplifier U1 is the negative input terminal. The reference voltage Vref is connected to the first input terminal of the operational amplifier unit 1204 through the first filtering unit 1203. The first filtering unit 1203 is a hardware circuit, for example, composed of circuit components such as capacitors and resistors. The first filtering unit 1203 is used to filter the reference voltage Vref.

[0079] Exemplarily, refer to Figure 5 , if the first resistor unit 1201 includes a first resistor R1, the second resistor unit 1202 includes a second resistor R2, and the operational amplifier unit 1204 includes an operational amplifier U1, then when the output of the isolation module 110 is Vout = I * G_th, the adjusted AC signal output by the conditioning module 120 is Vout = (I * G_th)R2’ / R1’ + Vref, where R2’ / R1’ is the gain of the conditioning module 120, R2’ is the resistance value of the second resistor R2, and R1’ is the resistance value of the first resistor R1. Among them, when R2’ / R1’ is equal to 1, that is, when the gain of the conditioning module 120 is equal to 1, the adjusted AC signal output by the conditioning module 120 is Vout = (I * G_th) + Vref.

[0080] In an exemplary embodiment, the first resistor unit 1201 and the second resistor unit 1202 satisfy the following conditions: when the supply voltage of the processing module 130 is equal to the supply voltage of the current sensor, the ratio of the equivalent resistance value of the second resistor unit 1202 to the equivalent resistance value of the first resistor unit 1201 is equal to 1, that is, the gain of the conditioning module 120 is equal to 1, and the equivalent resistance value of the second resistor unit 1202 and the equivalent resistance value of the first resistor unit 1201 can be set to be equal.

[0081] When the supply voltage of the processing module 130 is less than the supply voltage of the current sensor, the ratio of the equivalent resistance value of the second resistor unit 1202 to the equivalent resistance value of the first resistor unit 1201 is greater than zero and less than 1, that is, the gain of the conditioning module 120 is greater than zero and less than 1, to ensure that the amplitude of the adjusted AC signal output by the conditioning module 120 is less than or equal to the supply voltage of the processing module 13o.

[0082] In the embodiment of the present application, when the first resistance unit 1201 and the second resistance unit 1202 meet the above conditions, if the supply voltage of the processing module 130 is Vcc, then Vref = 1 / 2 * Vcc. In this way, when the processing module 130 samples the current signal through the ADC, it is centered around 1 / 2 * Vcc. The positive amplitude of the signal is Vcc, and the negative amplitude of the signal is 0V. This can not only sample the current signal over the full range but also avoid amplitude overrun.

[0083] In an exemplary embodiment, referring to Figure 5 , the first filtering unit 1203 includes a first filtering resistor R3 and a first filtering capacitor C2; the first end of the first filtering resistor R3 is connected to the first input end of the operational amplifier unit 1204, the first end of the first filtering resistor R3 is connected to the second end of the first resistance unit 1201, and the second end of the first filtering resistor R3 is connected to the reference voltage Vref; the first end of the first filtering capacitor C2 is connected to the first end of the first filtering resistor R3, and the second end of the first filtering capacitor C2 is connected to the second end of the first filtering resistor R3.

[0084] In an exemplary embodiment, referring to Figure 5 , the conditioning module 120 further includes a second filtering unit 1205; the first end of the second filtering unit 1205 is connected to the second input end of the operational amplifier unit 1204, and the second end of the second filtering unit 1205 is connected to the output end of the operational amplifier unit 1204; wherein, the second filtering unit 1205 is a hardware circuit, for example, composed of circuit components such as capacitors and resistors. The second filtering unit 1205 is used to filter the signal transmitted to the second input end of the operational amplifier unit 1204. Exemplarily, referring to Figure 5 , the second filtering unit 1205 includes a second filtering capacitor C3. The first end of the second filtering capacitor C3 is connected to the second input end of the operational amplifier U1, and the second end of the second filtering capacitor C3 is connected to the output end of the operational amplifier U2.

[0085] In an exemplary embodiment, when the supply voltage of the processing module 130 is equal to the supply voltage of the current sensor, in addition to setting the equivalent resistance value of the second resistance unit 1202 equal to the equivalent resistance value of the first resistance unit 1201 in the conditioning module 120 as shown in Figure 5 so that the gain of the conditioning module 120 is equal to 1, the conditioning module 120 can also be set as shown in Figure 6 , referring to Figure 6, the conditioning module 120 includes a third filtering unit 1206; the first end of the third filtering unit 1206 is connected to the output end of the isolation module 110, the first end of the third filtering unit 1206 is connected to the processing module 130, and the second end of the third filtering unit 1206 is connected to the reference voltage Vref. In this way, it is equivalent that the conditioning module 120 itself does not contain gain, and the conditioning module 120 does not need to apply gain to the isolated AC signal. Then, the adjusted AC signal output from the output end of the conditioning module 120 is Vout = (I * G_th) + Vref, which is substantially equivalent to the gain of the conditioning module 120 being equal to 1.

[0086] Among them, the reference voltage Vref is connected to the output end of the isolation module 110 through the third filtering unit 1206. The third filtering unit 1206 is a hardware circuit, for example, composed of circuit components such as capacitors and resistors. The third filtering unit 1206 is used to filter the reference voltage Vref; Exemplarily, in combination with Figure 5 and Figure 6 , the structure of the third filtering unit 1206 is the same as that of the first filtering unit 1203.

[0087] In an exemplary embodiment, in combination with Figure 5 and Figure 6 , the current sampling device 10 further includes a fourth filtering unit 140; the output end of the conditioning module 120 is connected to the processing module 130 through the fourth filtering unit 140, and the fourth filtering unit 140 is connected to the reference ground DGND; Among them, the fourth filtering unit 140 is a hardware circuit, for example, composed of circuit components such as capacitors and resistors. The fourth filtering unit 140 is used to filter the signal output from the output end of the conditioning module 120; Exemplarily, the fourth filtering unit 140 includes a second filtering resistor R4 and a third filtering capacitor C4; the first end of the second filtering resistor R4 is connected to the output end of the conditioning module 120, the second end of the second filtering resistor R4 is connected to the processing module 130, the first end of the third filtering capacitor C4 is connected to the second end of the second filtering resistor R4, and the second end of the third filtering capacitor C4 is connected to the reference ground DGND.

[0088] In an exemplary embodiment, referring to Figure 7 , the current sampling device 10 further includes a sampling module 150; the sampling module 150 is connected to the reference voltage Vref to sample the reference voltage Vref and output a sampling voltage; the first input end of the processing module 130 is connected to the output end of the conditioning module 120, and the second input end of the processing module 130 is connected to the output end of the sampling module 150; The processing module 130 is configured to:

[0089] Obtain the first sampled voltage V3 received at the second input terminal of the processing module 130 at the reference moment, and obtain the second sampled voltage V3_1 received at the second input terminal of the processing module 130 at the current moment; obtain the absolute value of the difference between the first sampled voltage V3 and the second sampled voltage V3_1, |V3_1 - V3| = V.

[0090] When the second sampled voltage V3_1 is less than the first sampled voltage V3, it indicates that during the period from the reference moment to the current moment, the reference voltage Vref decreases due to the influence of the surrounding environment, the structure of the conditioning module 120 itself, and the temperature drift of each device in the conditioning module 120, and the decrease amount is V. Therefore, the adjusted AC signal output by the conditioning module 120 at the current moment is superimposed on the absolute value of the above difference (i.e., Vout’ = Vout + V = (I * G_th)R2’’ / R1’ + Vref + V, where R2’’ is the equivalent resistance value of the second resistor unit 1202, and R1’’ is the equivalent resistance value of the first resistor unit 1201), and the sampled current value is determined according to the superimposed signal Vout’. Thus, the influence of the reference voltage Vref being affected by the surrounding environment, the structure of the conditioning module 120 itself, and the temperature drift of each device in the conditioning module 120 is improved, and the current sampling accuracy is further enhanced.

[0091] When the second sampled voltage V3_1 is greater than the first sampled voltage V3, it indicates that during the period from the reference moment to the current moment, the reference voltage Vref increases due to the influence of the surrounding environment, the structure of the conditioning module 120 itself, and the temperature drift of each device in the conditioning module 120, and the increase amount is V. Therefore, the adjusted AC signal output by the conditioning module 120 at the current moment is subtracted from the absolute value of the difference (i.e., Vout’ = Vout - △V = (I * G_th)R2’’ / R1’’ + Vref - △V), and the sampled current value is determined according to the subtracted signal Vout’. Thus, the influence of the reference voltage Vref being affected by the surrounding environment, the structure of the conditioning module 120 itself, and the temperature drift of each device in the conditioning module 120 is improved, and the current sampling accuracy is further enhanced.

[0092] When the second sampled voltage V3_1 is equal to the first sampled voltage V3, it indicates that during the period from the reference moment to the current moment, the reference voltage Vref remains unchanged, which is equivalent to V = 0. Therefore, Vout’ = Vout, and the sampled current value can be directly determined according to Vout.

[0093] Among them, the reference moment can be the first moment when the output of the current sensor stabilizes after the system is powered on for a period of time and current sampling is to start, serving as the reference moment; of course, the reference moment can also be other pre-specified moments; it can be understood that the reference voltage Vref of the reference moment is accurate and has not changed due to floating, drift, etc. At other moments, the reference voltage V can be obtained with the reference voltage Vref of the reference moment as the standard, and Vout can be calibrated with V to obtain Vout’, thereby improving the influence of the reference voltage Vref by the surrounding environment, the structure of the conditioning module 120 itself, and the temperature drift of each device in the conditioning module 120, and further improving the accuracy of current sampling. In addition, the specific structure of the sampling module 150 in the embodiments of the present application is not limited, and a conventional voltage sampling circuit can be used, as long as it can accurately and reliably sample the reference voltage Vref.

[0094] Exemplarily, the current sampling device 10 may further include a voltage reference generation module for generating the reference voltage Vref. There are various structural forms of the voltage reference generation module. For example, it includes circuits such as a DCDC Bulk buck circuit, an LDO buck circuit, a resistor voltage division circuit, an operational amplifier linear conditioning circuit, or a reference source, as long as it can provide a stable and reliable reference voltage Vref, and no specific limitation is made here; the sampling module 150 and the conditioning module 120 can both obtain the reference voltage Vref from the voltage reference generation module.

[0095] In an exemplary embodiment, the processing module 130 is further configured to: compare the adjusted AC signal output by the conditioning module 120 at the current moment with a preset voltage range. If the adjusted AC signal output by the conditioning module 120 at the current moment exceeds the preset voltage range, an output current sampling fault signal is output; where the preset voltage range is determined according to the first sampling voltage.

[0096] Among them, the first sampling voltage V3 is substantially the reference voltage Vref. Exemplarily, if Vout exceeds [0, 2V3] and is not within the preset range, it indicates that the deviation of Vout is too large and a sampling fault occurs. Therefore, the processing module 130 can output a current sampling fault signal, report the fault, alarm the abnormal current sampling, and can stop the current sampling until the fault is eliminated.

[0097] The embodiments of the present application can first determine whether the deviation of Vout is too large. When the deviation of Vout is very small, V and Vout’ are further determined, and then the sampled current value is determined according to Vout’, which is beneficial to improving the current sampling efficiency.

[0098] In an exemplary embodiment, the embodiments of the present application further provide a motor controller, which includes a current sensor and the current sampling device 10 provided in any of the above embodiments.

[0099] The motor controller and the current sampling device 10 provided by the embodiments of the present application belong to the same inventive concept, can solve the same technical problems, and thus achieve the same technical effects. The repeated content will not be elaborated here.

[0100] In an exemplary embodiment, the motor controller may include three current sensors and three current sampling devices 10. Each current sensor is used to sample one phase of the three-phase alternating current of the motor. The three current sampling devices 10 are connected to the three current sensors in one-to-one correspondence. Of course, in order to reduce costs, the three current sampling devices 10 can share a processing module 130. The external ADC can be multiple or one, and can be set according to actual applications.

[0101] In the description of this specification, the descriptions referring to terms such as "some embodiments", "other embodiments", etc. mean that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic descriptions of the above terms do not necessarily refer to the same embodiment or example.

[0102] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0103] The above-described embodiments only represent several implementation manners of the present application. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the present application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several deformations and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

Claims

1. A current sampling device, characterized in that, Comprising: An isolation module, a conditioning module, and a processing module; The input end of the isolation module is connected to the sampling output end of a current sensor, the output end of the isolation module is connected to the first input end of the conditioning module, the second input end of the conditioning module is connected to a reference voltage, and the output end of the conditioning module is connected to the processing module; wherein, The isolation module is used to isolate the bias voltage signal in the AC signal output from the sampling output end of the current sensor and output the isolated AC signal; The conditioning module is used to convert the negative voltage in the isolated AC signal to a positive voltage using the reference voltage and output the adjusted AC signal to the processing module; The processing module is used to determine the sampled current value based on the adjusted AC signal.

2. The current sampling device according to claim 1, characterized in that, The isolation module includes: a capacitor unit; The first end of the capacitor unit is connected to the sampling output end of the current sensor, and the second end of the capacitor unit is connected to the first input end of the conditioning module; The equivalent capacitance value of the capacitor unit is adapted to the operating frequency of the current sensor.

3. The current sampling device according to claim 1, characterized in that, The conditioning module includes: a first resistor unit, a second resistor unit, a first filtering unit, and an operational amplifier unit; The first end of the first resistor unit is connected to the output end of the isolation module, and the second end of the first resistor unit is connected to the first end of the first filtering unit; The first end of the first filtering unit is connected to the first input end of the operational amplifier unit, and the second end of the first filtering unit is connected to the reference voltage; The first end of the second resistor unit is connected to the second input end of the operational amplifier unit, and the second end of the second resistor unit is connected to the output end of the operational amplifier unit; The output end of the operational amplifier unit is connected to the processing module; Wherein, the conditioning module is further used to adjust the amplitude of the isolated AC signal using a gain coefficient, and the gain coefficient is determined according to the ratio of the equivalent resistance value of the second resistor unit to the equivalent resistance value of the first resistor unit.

4. The current sampling device according to claim 3, wherein, The first resistor unit and the second resistor unit satisfy the following conditions: When the supply voltage of the processing module is equal to the supply voltage of the current sensor, the ratio of the equivalent resistance value of the second resistor unit to the equivalent resistance value of the first resistor unit is equal to 1; When the supply voltage of the processing module is less than the supply voltage of the current sensor, the ratio of the equivalent resistance value of the second resistor unit to the equivalent resistance value of the first resistor unit is greater than zero and less than 1.

5. The current sampling device according to claim 3, characterized in that, The first filtering unit includes: a first filtering resistor and a first filtering capacitor; The first end of the first filtering resistor is connected to the first input end of the operational amplifier unit, the first end of the first filtering resistor is connected to the second end of the first resistor unit, and the second end of the first filtering resistor is connected to the reference voltage; The first end of the first filtering capacitor is connected to the first end of the first filtering resistor, and the second end of the first filtering capacitor is connected to the second end of the first filtering resistor.

6. The current sampling device according to claim 3, wherein, The conditioning module further includes: a second filtering unit; The first end of the second filtering unit is connected to the second input end of the operational amplifier unit, and the second end of the second filtering unit is connected to the output end of the operational amplifier unit; wherein, the second filtering unit is used to filter the signal transmitted to the second input end of the operational amplifier unit.

7. The current sampling device according to claim 1, characterized in that The conditioning module includes: a third filtering unit; The first end of the third filtering unit is connected to the output end of the isolation module, the first end of the third filtering unit is connected to the processing module, and the second end of the third filtering unit is connected to the reference voltage. Wherein, the power supply voltage of the processing module is equal to the power supply voltage of the current sensor.

8. The current sampling device according to any one of claims 1-7, characterized in that Further included: A fourth filtering unit; The output end of the conditioning module is connected to the processing module through the fourth filtering unit, and the fourth filtering unit is connected to the reference ground; wherein, the fourth filtering unit is used to filter the signal output from the output end of the conditioning module.

9. The current sampling device according to any one of claims 1-7, characterized in that, Further included: A sampling module; The sampling module is connected to the reference voltage to sample the reference voltage and output a sampled voltage. The first input end of the processing module is connected to the output end of the conditioning module, and the second input end of the processing module is connected to the output end of the sampling module; the processing module is configured to: Obtain a first sampled voltage received by the second input end of the processing module at a reference moment, and obtain a second sampled voltage received by the second input end of the processing module at the current moment; Obtain the absolute value of the difference between the first sampled voltage and the second sampled voltage; When the second sampled voltage is less than the first sampled voltage, superimpose the adjusted alternating current signal output by the conditioning module at the current moment on the absolute value of the difference, and determine the sampled current value according to the superimposed signal; When the second sampled voltage is greater than the first sampled voltage, subtract the absolute value of the difference from the adjusted alternating current signal output by the conditioning module at the current moment, and determine the sampled current value according to the subtracted signal.

10. The current sampling device according to claim 9, wherein The processing module is further configured to: Compare the adjusted alternating current signal output by the conditioning module at the current moment with a preset voltage range. If the adjusted alternating current signal output by the conditioning module at the current moment exceeds the preset voltage range, an overcurrent sampling fault signal is output; wherein, the preset voltage range is determined according to the first sampled voltage.

11. A motor controller, characterized in that, Including a current sensor and the current sampling device according to any one of claims 1-10.

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