Current sampling circuit, motor controller and inverter

Abstract

The utility model discloses a current sampling circuit, a motor controller and an inverter. The current sampling circuit comprises a current sensor and an analog-to-digital converter. The analog-to-digital converter is connected with the output end of the corresponding current sensor; wherein the reference voltage of the analog-to-digital converter and the power supply voltage of the correspondingly connected current sensor are provided by the same direct-current power supply; the current sensor is used for collecting a current signal of the collected equipment; and the analog-to-digital converter is used for converting the analog current signal acquired by the current sensor into a digital current signal. According to the embodiment of the invention, the output value of the current sensor and the power supply voltage of the current sensor are positively correlated, and the output value of the analog-to-digital converter and the reference voltage of the analog-to-digital converter are negatively correlated, so that the power supply voltage of the current sensor and the reference voltage of the analog-to-digital converter are powered by the same direct-current power supply; the output value of the analog-to-digital converter and the reference voltage are decoupled, and the sampling precision of the current sampling circuit is improved.

Description

Technical Field

[0001] The present application relates to the field of current electronic technology, and in particular to a current sampling circuit, a motor controller, and an inverter. Background Art

[0002] Current sampling circuits typically include a current sensor and an analog-to-digital converter (ADC). The current sensor is a device that converts the current signal into another analyzable signal, such as an analog voltage signal. The ADC converts the analog voltage signal output by the current sensor into a corresponding digital value.

[0003] The sampling accuracy of the current sampling circuit is crucial to the control system. Improving the sampling accuracy of the current sampling circuit is a technical problem that needs to be solved urgently in this field. Utility Model Content

[0004] Based on the above problems, the present application provides a current sampling circuit, a motor controller and an inverter to improve the sampling accuracy of the current sampling circuit.

[0005] The embodiments of this application disclose the following technical solutions:

[0006] In a first aspect, an embodiment of the present application provides a current sampling circuit, comprising: a current sensor and an analog-to-digital converter;

[0007] The analog-to-digital converter is connected to the output end of the corresponding current sensor; wherein the reference voltage of the analog-to-digital converter and the power supply voltage of the corresponding connected current sensor are provided by the same DC power supply;

[0008] Current sensor, used to collect current signals from the device being collected;

[0009] The analog-to-digital converter is used to convert the analog current signal collected by the current sensor into a digital current signal.

[0010] Optionally, the current signal of the device being collected includes a single-phase current signal, the input end of the analog-to-digital converter is connected to the output end of the current sensor, and the output end of the analog-to-digital converter outputs a digital current signal about the device being collected.

[0011] Optionally, the current of the device to be collected includes a three-phase current signal, and the current sensor includes a first current sensor, a second current sensor, and a third current sensor respectively used to collect the three-phase current signals.

[0012] Optionally, the analog-to-digital converter includes a first analog-to-digital converter and a second analog-to-digital converter;

[0013] The output end of the first current sensor is connected to the first analog-to-digital converter, and the output end of the second current sensor and the output end of the third current sensor are both connected to the second analog-to-digital converter; wherein, the power supply voltage of the first current sensor and the reference voltage of the first analog-to-digital converter are both provided by the first DC power supply, and the power supply voltage of the second current sensor, the power supply voltage of the third current sensor and the reference voltage of the second analog-to-digital converter are all provided by the second DC power supply.

[0014] Optionally, the analog-to-digital converter includes a first analog-to-digital converter, a second analog-to-digital converter, and a third analog-to-digital converter;

[0015] The output end of the first current sensor, the output end of the second current sensor and the output end of the third current sensor are respectively connected to the first analog-to-digital converter, the second analog-to-digital converter and the third analog-to-digital converter; wherein, the power supply voltage of the first current sensor and the reference voltage of the first analog-to-digital converter are both provided by the first DC power supply, the power supply voltage of the second current sensor and the reference voltage of the second analog-to-digital converter are both provided by the second DC power supply, and the power supply voltage of the third current sensor and the reference voltage of the third analog-to-digital converter are both provided by the third DC power supply.

[0016] Optionally, the analog-to-digital converter includes a first analog-to-digital converter;

[0017] The output end of the first current sensor, the output end of the second current sensor, and the output end of the third current sensor are all connected to the first analog-to-digital converter; wherein the power supply voltage of the first current sensor, the power supply voltage of the second current sensor, the power supply voltage of the third current sensor, and the reference voltage of the first analog-to-digital converter are all provided by the first DC power supply.

[0018] Optionally, the device further includes: a processor; wherein the power supply circuit of the processor includes a fourth capacitor, a fifth capacitor, a sixth capacitor, and a seventh capacitor, wherein the first ends of the fourth capacitor, the fifth capacitor, the sixth capacitor, and the seventh capacitor are connected together and to the ground, the second ends of the fourth capacitor and the fifth capacitor are connected together and to a fourth DC power supply, the second end of the sixth capacitor provides the first DC power supply, the second end of the seventh capacitor provides the second DC power supply, and the second ends of the fourth capacitor and the fifth capacitor provide power to the processor;

[0019] Each analog-to-digital converter is connected to a processor.

[0020] Optionally, it further includes: a filter circuit; wherein a first end of the filter circuit is connected to the output end of the current sensor, and a second end of the filter circuit is connected to the analog-to-digital converter.

[0021] In a second aspect, an embodiment of the present application provides a motor controller, comprising: a DC / AC power conversion circuit and a current sampling circuit in any embodiment of the first aspect;

[0022] The DC side of the DCAC power conversion circuit is used to connect to the DC bus, and the AC side of the DCAC power conversion circuit is used to connect to the motor;

[0023] The current sampling circuit is used to obtain the current signal output by the DCAC power conversion circuit.

[0024] In a third aspect, an embodiment of the present application provides an inverter, comprising: a DC-DC (Direct Current) power conversion circuit, a DC-AC (Alternating Current) power conversion circuit, and the current sampling circuit in any embodiment of the first aspect;

[0025] The first side of the DCDC power conversion circuit is used to connect to a DC source, the second side of the DCDC power conversion circuit is connected to the DC side of the DCAC power conversion circuit, and the AC side of the DCAC power conversion circuit is used to connect to the power grid;

[0026] The current sampling circuit is used to obtain the current signal output by the DCAC power conversion circuit.

[0027] In order to improve the sampling accuracy of the current sampling circuit, the embodiment of the present application utilizes the positive correlation between the output value of the current sensor and the power supply voltage of the current sensor, and the negative correlation between the output value of the analog-to-digital converter and the reference voltage of the analog-to-digital converter, so that the power supply voltage of the current sensor and the reference voltage of the analog-to-digital converter are powered by the same DC power supply, thereby decoupling the output value of the analog-to-digital converter and the reference voltage, thereby improving the sampling accuracy of the current sampling circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0029] Figure 1 A schematic diagram of the structure of a current sampling circuit provided in an embodiment of the present application;

[0030] Figure 2 A schematic diagram of the structure of another current sampling circuit provided in an embodiment of the present application;

[0031] Figure 3 A schematic diagram of the structure of another current sampling circuit provided in an embodiment of the present application;

[0032] Figure 4 A schematic structural diagram of another current sampling circuit provided in an embodiment of the present application;

[0033] Figure 5 A schematic diagram of the structure of a current sampling circuit provided in an embodiment of the present application;

[0034] Figure 6 A schematic structural diagram of a filter circuit provided in an embodiment of the present application;

[0035] Figure 7 A schematic diagram of a power supply circuit of a processor provided in an embodiment of the present application;

[0036] Figure 8 A schematic diagram of the structure of a motor controller provided in an embodiment of the present application;

[0037] Figure 9 A schematic structural diagram of an inverter provided in an embodiment of the present application. DETAILED DESCRIPTION

[0038] In order to help those skilled in the art better understand the present invention, the following will clearly and completely describe the technical solution in this embodiment in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0039] In the specification and claims of this utility model, the terms "first" and "second" are used to distinguish different objects, rather than to describe a specific order of objects. For example, "first current sensor" and "second current sensor" are used to distinguish different current sensors, rather than to describe a specific order of current sensors.

[0040] In this embodiment, words such as "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in this embodiment should not be interpreted as being preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner.

[0041] In the description of this embodiment, unless otherwise specified, “multiple” means two or more than two. For example, multiple processing units means two or more processing units, etc.; multiple elements means two or more elements, etc.

[0042] The power supply voltage of the current sensor in the current sampling circuit is provided by the first DC power supply V1, and the reference voltage of the analog-to-digital converter is provided by the second DC power supply V2. The output value Vs of the current sensor and the output value Ds of the analog-to-digital converter are respectively expressed as follows:

[0043]

[0044] Where Is represents the current signal of the device being collected, Ip represents the maximum range of the current signal sensor, and 4096 represents the digital value of the full scale with 12-bit accuracy of the analog-to-digital converter.

[0045] It can be seen that the accuracy of the analog-to-digital converter's output is closely related to the current sensor's power supply voltage V1 and the analog-to-digital converter's reference voltage V2. Specifically, the current sensor's output value Vs is positively correlated with the first DC power supply V1, while the analog-to-digital converter's output value Ds is negatively correlated with the second DC power supply V2.

[0046] To improve the sampling accuracy of the current sampling circuit, the present embodiment utilizes the positive correlation between the output value Vs of the current sensor and the first DC power supply V1, and the negative correlation between the output value Ds of the analog-to-digital converter and the second DC power supply V2. This ensures that the power supply voltage of the current sensor connected to the analog-to-digital converter and the reference voltage of the analog-to-digital converter are provided by the same DC source, such as V1. The output value Ds of the analog-to-digital converter is expressed as follows:

[0047]

[0048] As can be seen from the output expression of the analog-to-digital converter above, the output of the analog-to-digital converter is decoupled from the power supply voltage of the current sensor and the reference voltage of the analog converter, and is no longer affected by the accuracy of the power supply voltage of the current sensor and the reference voltage of the analog converter, thereby improving the sampling accuracy of the sampling circuit.

[0049] The technical solution of this application will be introduced below with reference to specific embodiments.

[0050] See also Figure 1 , which is a structural diagram of a current sampling circuit provided in an embodiment of the present application.

[0051] like Figure 1 As shown, the current sampling circuit includes: a current sensor 100 and an analog-to-digital converter 200;

[0052] The analog-to-digital converter 200 is connected to the output terminal of the corresponding current sensor 100 , and the reference voltage Vref of the analog-to-digital converter 200 and the power supply voltage Vdd of the corresponding current sensor 100 are provided by the same DC power supply V1 ;

[0053] The current sensor 100 is used to collect the current signal Is of the device being collected;

[0054] The analog-to-digital converter 200 is used to convert the analog current signal collected by the current sensor into a digital current signal Ds.

[0055] In the embodiment of the present application, the current sensor may be any one of a Hall sensor and a current transformer.

[0056] In an embodiment of the present application, a corresponding current sensor can be selected according to the field described by the device being collected. For example, when the device being collected belongs to the protection or metering instrument and semiconductor field in the power system, a current transformer can be selected as the current sensor; when the device being collected belongs to the fields of electric vehicles, electronics industry, and rail transportation, a Hall sensor can be selected as the current sensor.

[0057] In the embodiments of the present application, the current signal of the device being collected is not specifically limited. For example, the current signal Is of the device being collected can be a single-phase current signal or a three-phase current signal. Below, the embodiments of the present application will expand on the sampling circuit according to the type of current of the device being collected.

[0058] See again Figure 1 The current of the device being collected is a single-phase current signal. The analog-to-digital converter 200 is directly connected to the output end of the current sensor 100, and the analog-to-digital converter 200 outputs a digital current signal Ds about the device being collected.

[0059] When the current signal of the collected device is a three-phase current signal, the embodiment of the present application does not specifically limit the number of current sensors corresponding to the analog-to-digital converter. For example, one analog-to-digital converter corresponds to one current sensor, one analog-to-digital converter corresponds to two current sensors, or one analog-to-digital converter corresponds to three current sensors.

[0060] In one possible implementation, Figure 2As shown, one analog-to-digital converter corresponds to three current sensors. The current signals of the device being collected include Ia, Ib, and Ic, and the current sensor 100 includes a first current sensor 110, a second current sensor 120, and a third current sensor 130. The analog-to-digital converter 200 is connected to the output terminals of the first current sensor 110, the second current sensor 120, and the third current sensor 130. The power supply voltages Vdd1, Vdd2, and Vdd3 of the first current sensor 110, the second current sensor 120, and the third current sensor 130, as well as the reference voltage Vref of the analog-to-digital converter 200, are all provided by a first DC power supply V1. The analog-to-digital converter 200 converts Ia, Ib, and Ic from analog current signals into digital current signals Da, Db, and Dc.

[0061] For example, Da, Db and Dc are respectively represented as follows:

[0062]

[0063] Wherein, Va, Vb and Vc represent the output value of the first current sensor, the output value of the second current sensor and the output value of the third current sensor respectively.

[0064] As can be seen, Da is decoupled from the first current sensor's power supply voltage Vdd1 and the analog-to-digital converter's reference voltage Vref. Db is decoupled from the second current sensor's power supply voltage Vdd2 and the analog-to-digital converter's reference voltage Vref. Dc is decoupled from the third current sensor's power supply voltage Vdd3 and the analog-to-digital converter's reference voltage Vref. Da, Db, and Dc are no longer affected by the accuracy of their corresponding power supply voltages and reference voltages, thereby improving the sampling accuracy of the sampling circuit.

[0065] In one possible implementation, Figure 3As shown, one analog-to-digital converter corresponds to one current sensor. The current signals of the device being collected include Ia, Ib, and Ic. The current sensor 100 includes a first current sensor 110, a second current sensor 120, and a third current sensor 130. The analog-to-digital converter 200 includes a first analog-to-digital converter 210, a second analog-to-digital converter 220, and a third analog-to-digital converter 230. The first analog-to-digital converter 210 is connected to the output of the first current sensor 110, the second analog-to-digital converter 220 is connected to the output of the second current sensor 120, and the third analog-to-digital converter 230 is connected to the third current sensor 130. The power supply voltage Vdd1 of the first current sensor 110 and the reference voltage Vref1 of the first analog-to-digital converter 210 are provided by a first DC power supply V1. The power supply voltage Vdd2 of the second current sensor 120 and the reference voltage Vref2 of the second analog-to-digital converter 220 are provided by a second DC power supply V2. The power supply voltage Vdd3 of the third current sensor 130 and the reference voltage Vref3 of the third analog-to-digital converter 230 are provided by a third DC power supply V3. The first analog-to-digital converter 210 , the second analog-to-digital converter 220 , and the third analog-to-digital converter 230 convert Ia, Ib, and Ic from analog current signals into digital current signals Da, Db, and Dc, respectively.

[0066] For example, Da, Db and Dc are respectively represented as follows:

[0067]

[0068] It can be seen that Da is decoupled from the power supply voltage Vdd1 of the first current sensor and the reference voltage Vref1 of the analog-to-digital converter, Db is decoupled from the power supply voltage Vdd2 of the second current sensor and the reference voltage Vref2 of the analog-to-digital converter, and Dc is decoupled from the power supply voltage Vdd3 of the third current sensor and the reference voltage Vref3 of the analog-to-digital converter. Da, Db, and Dc are no longer affected by the accuracy of the corresponding power supply voltage and reference voltage, thereby improving the sampling accuracy of the sampling circuit. In addition, in the embodiment of the present application, each phase current is powered by an independent DC current source, which can avoid the common cause failure of the three-phase current sampling caused by an abnormal DC power supply, that is, the inability to achieve equal frequency, equal amplitude, and 120-degree phase difference between the three-phase currents.

[0069] In one possible implementation, Figure 4As shown, one analog-to-digital converter corresponds to one current sensor or two current sensors. The current signals of the device being collected include Ia, Ib, and Ic. The current sensor 100 includes a first current sensor 110, a second current sensor 120, and a third current sensor 130. The analog-to-digital converter 200 includes a first analog-to-digital converter 210 and a second analog-to-digital converter 220. The first analog-to-digital converter 210 is connected to the output of the first current sensor 110, and the second analog-to-digital converter 220 is connected to the output of the second current sensor 120 and the third current sensor 130. The power supply voltage Vdd1 of the first current sensor 110 and the reference voltage Vref1 of the first analog-to-digital converter 210 are provided by a first DC power supply V1. The power supply voltage Vdd2 of the second current sensor 120, the power supply voltage Vdd3 of the third current sensor 130, and the reference voltage Vref2 of the second analog-to-digital converter 220 are provided by a second DC power supply V2. The first analog-to-digital converter 210 converts Ia from an analog current signal into a digital current signal Da, and the second analog-to-digital converter 220 converts Ib and Ic from analog current signals into digital current signals Da, Db, and Dc, respectively.

[0070] For example, Da, Db and Dc are respectively represented as follows:

[0071]

[0072] It can be seen that Da is decoupled from the power supply voltage Vdd1 of the first current sensor and the reference voltage Vref1 of the analog-to-digital converter, Db is decoupled from the power supply voltage Vdd2 of the second current sensor and the reference voltage Vref2 of the analog-to-digital converter, and Dc is decoupled from the power supply voltage Vdd2 of the third current sensor and the reference voltage Vref2 of the analog-to-digital converter. Da, Db, and Dc are no longer affected by the accuracy of the corresponding power supply voltage and reference voltage, thereby improving the sampling accuracy of the sampling circuit. In addition, when using two DC power supplies, the embodiment of the present application avoids common cause failure of three-phase current sampling caused by abnormality of one DC power supply, that is, it is impossible to achieve equal frequency, equal amplitude, and 120-degree phase difference between the three-phase currents.

[0073] In addition, in order to remove ripples in the output signal of the current sensor, the embodiment of the present application connects a filter circuit between the output end of the current sensor and the analog-to-digital converter.

[0074] like Figure 5As shown, the current sampling circuit includes a first filter circuit 310, a second filter circuit 320, and a third filter circuit 330. A first end of the first filter circuit 310 is connected to the output end of the first current sensor 110, and a second end of the first filter circuit 310 is connected to the first analog-to-digital converter 210; a first end of the second filter circuit 320 is connected to the output end of the second current sensor 120, and a second end of the second filter circuit 320 is connected to the second analog-to-digital converter 220; a first end of the third filter circuit 330 is connected to the output end of the third current sensor 130, and a second end of the third filter circuit 330 is connected to the third analog-to-digital converter 230.

[0075] It should be understood that the first filter circuit 310, the second filter circuit 320 and the third filter circuit have the same structure. In the following embodiments of the present application, the first filter circuit 310 is taken as an example to introduce the filter circuit.

[0076] like Figure 6 As shown, the filter circuit 310 includes a resistor R1, a resistor R2, a resistor R3, a capacitor C1, a capacitor C2, and a capacitor C3. The first end of the resistor R2 is connected to the first end of the resistor R1, the first end of the capacitor C1, and the output end of the current sensor. The second end of the resistor R2 is connected to the first end of the capacitor C2 and the first end of the resistor R3. The second end of the resistor R3 is connected to the first end of the capacitor C3 and the analog-to-digital converter. The second ends of the resistor R1, the capacitor C1, the capacitor C2, and the capacitor C3 are all connected to ground.

[0077] In the embodiment of the present application, the filtering circuit can remove noise and interference in the current signal, further improving the sampling accuracy of the current sampling circuit.

[0078] In the embodiments of the present application, the existence of the analog-to-digital converter is not specifically limited. For example, the analog-to-digital converter can be an analog-to-digital conversion unit in a processor chip, or a chip independent of the processor.

[0079] When the analog-to-digital converter is a chip independent of the processor, the output end of each analog-to-digital converter is connected to the processor; when the analog-to-digital converter is an analog-to-digital conversion unit in the processor, each analog conversion unit is connected to the processor.

[0080] like Figure 7As shown, an embodiment of the present application provides a power supply circuit for a processor. The power supply circuit of the processor includes a fourth capacitor C4, a fifth capacitor C5, a sixth capacitor C6, and a seventh capacitor C7. The first ends of capacitors C4, C5, C6, and C7 are connected together and connected to the ground; the second ends of capacitors C4 and C5 are connected together and connected to a DC power supply V4, the second end of capacitor C6 provides a first DC power supply V1, the second end of capacitor C7 provides a second DC power supply V2, and the second end of capacitor C4 and the second end of capacitor C5 provide a power supply voltage Vddm for the processor.

[0081] See also Figure 8 , which is a structural diagram of a motor controller provided in an embodiment of the present application.

[0082] like Figure 8 As shown, the motor controller includes: a DCAC power conversion circuit 810 and a current sampling circuit 820 in any of the aforementioned embodiments. The DC side of the DCAC power conversion circuit 810 is used to connect to the battery pack DC, and the AC side of the DCAC power conversion circuit 810 is used to connect to the motor.

[0083] The current sampling circuit 820 is used to collect the current signal output by the DCAC power conversion circuit 810 so that the processor can control the DCAC power conversion circuit 810 through the digital current signal output by the current sampling circuit 820 .

[0084] See also Figure 9 , which is a structural schematic diagram of an inverter provided in an embodiment of the present application.

[0085] like Figure 9 As shown, the inverter includes: a DCDC power conversion circuit 910, a DCAC power conversion circuit 920, and a current sampling circuit 930 in any of the aforementioned embodiments; a first side of the DCDC power conversion circuit 910 is used to connect to a DC source DC, a second side of the DCDC power conversion circuit 910 is connected to the DC side of the DCAC power conversion circuit 920, and an AC side of the DCAC power conversion circuit 920 is used to connect to a power grid.

[0086] The current sampling circuit 930 is used to obtain the current signal output by the DCAC power conversion circuit 920 so that the processor can control the DCAC power conversion circuit 920 through the digital current signal output by the current sampling circuit 930 .

[0087] The above is merely one specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A current sampling circuit, characterized in that: include: Current sensor and analog-to-digital converter; The analog-to-digital converter is connected to the output end of the corresponding current sensor; wherein the reference voltage of the analog-to-digital converter and the power supply voltage of the corresponding connected current sensor are provided by the same DC power supply; The current sensor is used to collect the current signal of the device being collected; The analog-to-digital converter is used to convert the analog current signal collected by the current sensor into a digital current signal.

2. The current sampling circuit according to claim 1, characterized in that: The current signal of the device being collected includes a single-phase current signal. The input end of the analog-to-digital converter is connected to the output end of the current sensor, and the output end of the analog-to-digital converter outputs a digital current signal about the device being collected.

3. The current sampling circuit according to claim 1, characterized in that: The current of the device to be collected includes a three-phase current signal, and the current sensor includes a first current sensor, a second current sensor, and a third current sensor, respectively used to collect the three-phase current signal.

4. The current sampling circuit according to claim 3, characterized in that: The analog-to-digital converter includes a first analog-to-digital converter and a second analog-to-digital converter; The output end of the first current sensor is connected to the first analog-to-digital converter, and the output end of the second current sensor and the output end of the third current sensor are both connected to the second analog-to-digital converter; wherein, the power supply voltage of the first current sensor and the reference voltage of the first analog-to-digital converter are both provided by a first DC power supply, and the power supply voltage of the second current sensor, the power supply voltage of the third current sensor, and the reference voltage of the second analog-to-digital converter are all provided by a second DC power supply.

5. The current sampling circuit according to claim 3, characterized in that: The analog-to-digital converter includes a first analog-to-digital converter, a second analog-to-digital converter and a third analog-to-digital converter; The output end of the first current sensor, the output end of the second current sensor, and the output end of the third current sensor are respectively connected to the first analog-to-digital converter, the second analog-to-digital converter, and the third analog-to-digital converter; wherein, the power supply voltage of the first current sensor and the reference voltage of the first analog-to-digital converter are both provided by a first DC power supply, the power supply voltage of the second current sensor and the reference voltage of the second analog-to-digital converter are both provided by a second DC power supply, and the power supply voltage of the third current sensor and the reference voltage of the third analog-to-digital converter are both provided by a third DC power supply.

6. The current sampling circuit according to claim 3, characterized in that: The analog-to-digital converter includes a first analog-to-digital converter; The output end of the first current sensor, the output end of the second current sensor, and the output end of the third current sensor are all connected to the first analog-to-digital converter; wherein the power supply voltage of the first current sensor, the power supply voltage of the second current sensor, the power supply voltage of the third current sensor, and the reference voltage of the first analog-to-digital converter are all provided by a first DC power supply.

7. The current sampling circuit according to any one of claims 1 to 6, characterized in that: Also includes: a processor; wherein the power supply circuit of the processor includes a fourth capacitor, a fifth capacitor, a sixth capacitor, and a seventh capacitor, wherein the first ends of the fourth capacitor, the fifth capacitor, the sixth capacitor, and the seventh capacitor are connected together and to a ground, the second ends of the fourth capacitor and the fifth capacitor are connected together and to a fourth DC power supply, the second end of the sixth capacitor provides the first DC power supply, the second end of the seventh capacitor provides the second DC power supply, and the second ends of the fourth capacitor and the fifth capacitor provide power to the processor; Each of the analog-to-digital converters is connected to the processor.

8. The current sampling circuit according to claim 1, wherein: Also includes: filter circuit; A first end of the filter circuit is connected to the output end of the current sensor, and a second end of the filter circuit is connected to the analog-to-digital converter.

9. A motor controller, characterized in that: include: A DC / AC power conversion circuit and a current sampling circuit according to any one of claims 1 to 8; The DC side of the DCAC power conversion circuit is used to connect to a DC bus, and the AC side of the DCAC power conversion circuit is used to connect to a motor; The current sampling circuit is used to obtain the current output by the DCAC power conversion circuit.

10. An inverter, characterized in that: include: A DC-DC (Direct Current Direct Current) power conversion circuit, a DC-AC (Alternating Current Alternating Current) power conversion circuit, and a current sampling circuit according to any one of claims 1 to 8; The first side of the DCDC power conversion circuit is used to connect to a DC source, the second side of the DCDC power conversion circuit is connected to the DC side of the DCAC power conversion circuit, and the AC side of the DCAC power conversion circuit is used to connect to a power grid; The current sampling circuit is used to obtain the current output by the DCAC power conversion circuit.

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