Current sampling circuit and current reconstruction method and device

Abstract

The invention discloses a current sampling circuit and a current reconstruction method and device, and belongs to the technical field of electronic equipment. The current sampling circuit comprises a bus capacitor, a motor, an inverter circuit, a sampling circuit, a voltage acquisition circuit and a current processing circuit. The sampling circuit comprises a first resistor, a second resistor and a third resistor, the inverter circuit comprises a first complementary switch circuit, a second complementary switch circuit and a third complementary switch circuit, and the first complementary switch circuit is further connected with a first phase current output end of the motor and the first resistor; the second complementary switch circuit is also connected with the second phase current output end of the motor and the second resistor; the third complementary switch circuit is also connected with a third phase current output end of the motor and the target node; the voltage acquisition circuit is used for acquiring the voltage between each complementary switch circuit and the bus capacitor through the sampling circuit; the current processing circuit is used for converting the voltage into current and outputting the current.

Description

Technical Field

[0001] The present application belongs to the technical field of electronic equipment, and specifically relates to a current sampling circuit, a current reconstruction method and a device. Background Art

[0002] Permanent Magnet Synchronous Motor (PMSM) is a synchronous motor that uses permanent magnets to generate magnetic fields. It has the advantages of simple structure, small size, high efficiency, and high power factor, and is widely used in various fields. The control adjustment of the permanent magnet synchronous motor depends on the current value of the three-phase current it outputs. Therefore, how to effectively collect the three-phase current of the permanent magnet synchronous motor has become an important research direction.

[0003] Currently, there is a circuit that uses two sampling resistors to sample the three-phase current of a permanent magnet synchronous motor. It indirectly samples two-phase currents of the three-phase current through the two sampling resistors, and then further calculates the sampled two-phase currents to obtain the three-phase current of the permanent magnet synchronous motor.

[0004] However, the current three-phase current sampling circuit with dual sampling resistors needs to reserve a specific minimum sampling time to collect phase current within the minimum sampling time, but this causes energy waste of the bus voltage within the minimum sampling time period, resulting in a low bus voltage utilization rate. Summary of the invention

[0005] The embodiments of the present application provide a current sampling circuit, a current reconstruction method and a device, which can improve the bus voltage utilization rate.

[0006] In a first aspect, a current sampling circuit is provided, the current sampling circuit comprising: a bus capacitor, a motor, an inverter circuit, a sampling circuit, a voltage acquisition circuit and a current processing circuit;

[0007] The sampling circuit includes a first resistor, a second resistor and a third resistor, the inverter circuit includes a first complementary switch circuit, a second complementary switch circuit and a third complementary switch circuit, all of which are connected to the bus capacitor, the first complementary switch circuit is also connected to the first phase current output end of the motor and the first resistor, and is used to control the connection or disconnection of the first phase current output end and the first resistor;

[0008] The second complementary switch circuit is also connected to the second phase current output terminal of the motor and the second resistor, and is used to control the connection or disconnection between the second phase current output terminal and the second resistor;

[0009] The third complementary switch circuit is also connected to the third phase current output terminal of the motor and the target node, and is used to control the connection or disconnection between the third phase current output terminal and the target node, and the first resistor and the second resistor are connected to the bus capacitor through the target node and the third resistor;

[0010] The voltage collection circuit is connected to the sampling circuit and is used to collect the voltage between each complementary switch circuit through the sampling circuit and the bus capacitor;

[0011] The current processing circuit is connected to the voltage acquisition circuit, and is used for converting the voltage into current and outputting the current.

[0012] Optionally, the voltage acquisition circuit includes a first operational amplifier and a second operational amplifier;

[0013] The first operational amplifier is connected to the first resistor, the third resistor and the current processing circuit respectively, and is used to amplify the voltage across the first resistor and the third resistor, and output the amplified voltage to the current processing circuit;

[0014] The second operational amplifier is connected to the second resistor, the third resistor and the current processing circuit respectively, and is used to amplify the voltage across the second resistor and the third resistor, and output the amplified voltage to the current processing circuit.

[0015] Optionally, the first complementary switch circuit comprises a first transistor and a second transistor connected in series, a path between the first transistor and the second transistor is connected to the first phase current output terminal, and the second transistor is connected to the first resistor;

[0016] The second complementary switch circuit comprises a third transistor and a fourth transistor connected in series, a path between the third transistor and the fourth transistor is connected to the second phase current output terminal, and the fourth transistor is connected to the second resistor;

[0017] The third complementary switch circuit includes a fifth transistor and a sixth transistor connected in series, the path between the fifth transistor and the sixth transistor is connected to the third phase current output terminal, the sixth transistor is connected to the target node, the first transistor, the third transistor and the fifth transistor are all connected to the bus capacitor, the first phase current output terminal is the U phase current output terminal, the second phase current output terminal is the V phase current output terminal, and the third phase current output terminal is the W phase current output terminal.

[0018] In a second aspect, a current reconstruction method is provided, which is applied to any current sampling circuit described in the first aspect, and the method includes:

[0019] When the motor is located in any target sector of the plurality of sectors, collecting target on-off states of the first complementary switch circuit, the second complementary switch circuit, and the third complementary switch circuit in the current sampling circuit;

[0020] According to the target corresponding relationship between the on-off state of the sector, the first complementary switch circuit, the second complementary switch circuit, and the third complementary switch circuit and the target sampling time, and the target on-off state, when the on-off state corresponding to the target sampling time reaching the target sector is determined, the voltage output by the voltage acquisition circuit at the target sampling time is acquired;

[0021] The three-phase current corresponding to the target sector is constructed according to the voltage, the resistance value of the first resistor, the resistance value of the second resistor and the resistance value of the third resistor, so as to obtain the three-phase current corresponding to each of the sectors.

[0022] Optionally, the voltage acquisition circuit includes the first operational amplifier and the second operational amplifier; and when determining the on-off state corresponding to the target sampling moment of reaching the target sector, acquiring the voltage output by the voltage acquisition circuit at the target sampling moment includes:

[0023] When the on / off state corresponding to the target sampling time at which the target sector is reached is determined, a first voltage output by the first operational amplifier at the target sampling time is collected, and a second voltage output by the second operational amplifier at the target sampling time is collected.

[0024] Optionally, the target sampling moment in the target corresponding relationship is a moment determination function, and when determining the on-off state corresponding to the target sampling moment of reaching the target sector, collecting a first voltage output by the first operational amplifier at the target sampling moment, and collecting a second voltage output by the second operational amplifier at the target sampling moment, comprises:

[0025] In the case of determining the on-off state corresponding to the target sampling moment of reaching the target sector, obtaining a time determination function corresponding to the target on-off state in the target corresponding relationship, the time determination function indicating the correlation between the target sampling moment and the switching cycle of the complementary switching circuit;

[0026] Determine a target sampling time within the switching cycle according to the time determination function;

[0027] A first voltage output by the first operational amplifier at the target sampling time is collected, and a second voltage output by the second operational amplifier at the target sampling time is collected.

[0028] Optionally, the current sampling circuit includes a first transistor, a second transistor, a third transistor, a fourth transistor, a fifth transistor and a sixth transistor; the collecting of target on-off states of the first complementary switch circuit, the second complementary switch circuit and the third complementary switch circuit in the current sampling circuit includes: collecting target on-off states of the second transistor, the fourth transistor and the sixth transistor;

[0029] The target correspondence between the on-off state of the sector, the first complementary switch circuit, the second complementary switch circuit and the third complementary switch circuit and the target sampling time includes: the target correspondence between the on-off state of the sector, the second transistor, the fourth transistor and the sixth transistor and the target sampling time.

[0030] Optionally, constructing the three-phase current corresponding to the target sector according to the voltage, the resistance value of the first resistor, the resistance value of the second resistor, and the resistance value of the third resistor to obtain the three-phase current corresponding to each of the sectors includes:

[0031] Determine the target conversion relation of the first phase current, the target conversion relation of the second phase current, and the target conversion relation of the third phase current corresponding to the target sector according to the corresponding relationship among the sectors, the conversion relation of the first phase current, the conversion relation of the second phase current, and the conversion relation of the third phase current;

[0032] According to the target conversion relationship, the three-phase current corresponding to each sector is obtained by converting the voltage, the resistance value of the first resistor, the resistance value of the second resistor and the resistance value of the third resistor.

[0033] In a third aspect, a current reconstruction device is provided, wherein the current reconstruction device is provided with any current sampling circuit described in the first aspect, and the device comprises:

[0034] a collection module, configured to collect target on-off states of the first complementary switch circuit, the second complementary switch circuit, and the third complementary switch circuit in the current sampling circuit when the motor is located in any target sector of the plurality of sectors;

[0035] The acquisition module is further configured to acquire the voltage output by the voltage acquisition circuit at the target sampling time when the on-off state corresponding to the target sampling time at which the target sector is reached is determined, based on the target corresponding relationship between the on-off state of the sector, the first complementary switch circuit, the second complementary switch circuit, and the third complementary switch circuit and the target sampling time, and the target on-off state;

[0036] A construction module is used to construct the three-phase current corresponding to the target sector according to the voltage, the resistance value of the first resistor, the resistance value of the second resistor and the resistance value of the third resistor, so as to obtain the three-phase current corresponding to each of the sectors.

[0037] In a fourth aspect, an electronic device is provided, comprising a processor, a memory and a current sampling circuit as described in any one of the first aspects; the memory is used to store a computer program; and the processor is used to implement any one of the methods described in the second aspect when executing the program stored in the memory.

[0038] In an embodiment of the present application, a current sampling circuit includes: a bus capacitor, a motor, an inverter circuit, a sampling circuit, a voltage acquisition circuit and a current processing circuit. The sampling circuit includes a first resistor, a second resistor and a third resistor. The inverter circuit includes a first complementary switch circuit, a second complementary switch circuit and a third complementary switch circuit. The first complementary switch circuit is connected to the first phase current output terminal of the motor and the first resistor, and is used to control the connection or disconnection of the first phase current output terminal and the first resistor. The second complementary switch circuit is also connected to the second phase current output terminal of the motor and the second resistor, and is used to control the connection or disconnection of the second phase current output terminal and the second resistor. The third complementary switch circuit is also connected to the third phase current output terminal of the motor and the target node, and is used to control the connection or disconnection of the third phase current output terminal and the target node, and the first resistor and the second resistor are connected to the bus capacitor through the target node and the third resistor. The voltage acquisition circuit is used to collect the voltage between each complementary switch circuit through the sampling circuit and the bus capacitor, so that the current processing circuit converts the voltage into current and outputs the current. In this technical solution, as long as there is a complementary switch circuit in the inverter circuit to control the connection, the voltage acquisition circuit can collect the phase current of the motor through the current processing circuit. The inverter circuit can often be in a state where at least one complementary switch circuit is controlled to be connected. Therefore, compared with the related art, there is no need to reserve a specific minimum sampling time, thereby improving the bus voltage utilization rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is one of the schematic diagrams of the minimum sampling time provided by the related technology;

[0040] Figure 2 It is one of the schematic diagrams of the current sampling circuit provided in the embodiment of the present application;

[0041] Figure 3 This is the second schematic diagram of the current sampling circuit provided in the embodiment of the present application;

[0042] Figure 4 This is the third schematic diagram of the current sampling circuit provided in the embodiment of the present application;

[0043] Figure 5This is the fourth schematic diagram of the current sampling circuit provided in the embodiment of the present application;

[0044] Figure 6 This is the fifth schematic diagram of the current sampling circuit provided in the embodiment of the present application;

[0045] Figure 7 This is the sixth schematic diagram of the current sampling circuit provided in the embodiment of the present application;

[0046] Figure 8 This is one of the flow charts of the current reconstruction method provided in the embodiment of the present application;

[0047] Fig. 9 It is one of the six-sector schematic diagrams provided in the embodiment of the present application;

[0048] Fig.10 It is one of the transistor state schematic diagrams provided in the embodiment of the present application;

[0049] Fig.11 This is the second transistor state schematic diagram provided in the embodiment of the present application;

[0050] Fig.12 This is the third transistor state schematic diagram provided in the embodiment of the present application;

[0051] Fig.13 This is the fourth transistor state schematic diagram provided in the embodiment of the present application;

[0052] Fig.14 This is the fifth transistor state schematic diagram provided in the embodiment of the present application;

[0053] Fig.15 This is the sixth transistor state schematic diagram provided in the embodiment of the present application;

[0054] Fig.16 This is one of the block diagrams of the current reconstruction device provided in the embodiment of the present application. DETAILED DESCRIPTION

[0055] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0056] Permanent Magnet Synchronous Motor (PMSM) is a synchronous motor that uses permanent magnets to generate magnetic fields. It has the advantages of simple structure, small size, high efficiency, and high power factor, and is widely used in various fields. The control adjustment of the permanent magnet synchronous motor depends on the current value of the three-phase current it outputs. Therefore, how to effectively collect the three-phase current of the permanent magnet synchronous motor has become an important research direction.

[0057] Currently, there is a circuit that uses two sampling resistors to sample the three-phase current of a permanent magnet synchronous motor. It indirectly samples two-phase currents of the three-phase current through the two sampling resistors, and then further calculates the sampled two-phase currents to obtain the three-phase current of the permanent magnet synchronous motor.

[0058] However, the current three-phase current sampling circuit with dual sampling resistors needs to reserve a specific minimum sampling time to collect the phase current within the minimum sampling time. Figure 1 As shown, a minimum sampling time is required in the three-phase current sampling circuit of the current double sampling resistor, so that the three-phase current output end of the motor is connected to both sampling resistors, and then the three-phase current flows to the double sampling resistor to ensure that the phase current can be collected. However, this requires an additional control circuit to add a specific minimum sampling time Tim. During this minimum sampling time, the bus voltage wastes energy because it does not participate in normal operation, and there is a problem of low bus voltage utilization.

[0059] Please refer to Figure 2 , which shows a circuit diagram of a current sampling circuit provided by an embodiment of the present application. Figure 2 As shown, the current sampling circuit includes: a bus capacitor C, a motor 201 , an inverter circuit 202 , a sampling circuit 203 , a voltage acquisition circuit 204 and a current processing circuit 205 .

[0060] The sampling circuit 203 includes: a first resistor R1, a second resistor R2 and a third resistor R3. The inverter circuit 202 includes: a first complementary switch circuit 2021, a second complementary switch circuit 2022 and a third complementary switch circuit 2023 all connected to the bus capacitor C.

[0061] The first complementary switch circuit 2021 is also connected to the first phase current output terminal of the motor and the first resistor R1. The first complementary switch circuit 2021 is used to control the connection or disconnection of the first phase current output terminal and the first resistor R1. The second complementary switch circuit 2022 is also connected to the second phase current output terminal of the motor and the second resistor R2. The second complementary switch circuit 2022 is used to control the connection or disconnection of the second phase current output terminal and the second resistor R2. The third complementary switch circuit 2023 is also connected to the third phase current output terminal of the motor and the target node O. The third complementary switch circuit 2023 is used to control the connection or disconnection of the third phase current output terminal and the target node O. The first resistor R1 and the second resistor R2 are connected to the bus capacitor C through the target node O and the third resistor R3.

[0062] The voltage collection circuit 204 is connected to the sampling circuit 203. The voltage collection circuit 204 is used to collect the voltage between each complementary switch circuit (ie, the first complementary switch circuit 2021, the second complementary switch circuit 2022, and the third complementary switch circuit 2023) through the sampling circuit 203 and the bus capacitor C.

[0063] The current processing circuit 205 is connected to the voltage acquisition circuit 204. The current processing circuit 205 is used to convert the voltage into current and output the current.

[0064] In an alternative case, if Figure 2 As shown, the first phase current output terminal is the U phase current output terminal. The second phase current output terminal is the V phase current output terminal. The third phase current output terminal is the W phase current output terminal. The first complementary switch circuit 2021 is used to control the connection or disconnection between the U phase current output terminal and the first resistor R1. The second complementary switch circuit 2022 is used to control the connection or disconnection between the V phase current output terminal and the second resistor R2. The third complementary switch circuit 2023 is used to control the connection or disconnection between the W phase current output terminal and the target node O.

[0065] When only the first complementary switch circuit 2021 controls the connection between the U-phase current output terminal and the first resistor R1, the U-phase current output terminal of the motor outputs the U-phase current, and the U-phase current passes through the first complementary switch circuit 2021, flows through the first resistor R1, the third resistor R3 to the bus capacitor C. The voltage acquisition circuit 204 is used to collect the voltage between the first complementary switch circuit 2021 and the bus capacitor C, that is, to collect the voltage between the U-phase current input terminal of the first resistor R1 and the U-phase current output terminal of the third resistor R3. The current processing circuit 205 can be used to convert the voltage into current and collect the U-phase current.

[0066] Similarly, when only the second complementary switch circuit 2022 controls the connection between the V-phase current output terminal and the second resistor R2, the V-phase current output terminal of the motor outputs the V-phase current, and the V-phase current passes through the second complementary switch circuit 2022, flows through the second resistor R2, the third resistor R3 to the bus capacitor C. The voltage acquisition circuit 204 is used to collect the voltage between the second complementary switch circuit 2022 and the bus capacitor C, that is, to collect the voltage between the V-phase current input terminal of the second resistor R2 and the V-phase current output terminal of the third resistor R3. The current processing circuit 205 can be used to convert the voltage into current and collect the V-phase current.

[0067] Similarly, when only the third complementary switch circuit 2023 controls the connection between the W-phase current output terminal and the target node O, the W-phase current output terminal of the motor outputs the W-phase current, and the W-phase current passes through the third complementary switch circuit 2023, flows through the third resistor R3 to the bus capacitor C. The voltage acquisition circuit 204 is used to collect the voltage between the third complementary switch circuit 2023 and the bus capacitor C, that is, to collect the voltage across the third resistor R3. The current processing circuit 205 can be used to convert the voltage into a current and collect the W-phase current.

[0068] Obviously, when at least one of the first complementary switch circuit 2021, the second complementary switch circuit 2022 and the third complementary switch circuit 2023 is connected, a single-phase current will flow through the resistors (collectively referred to as the first resistor R1, the second resistor R2 and the third resistor R3) in the sampling circuit 203 to the bus capacitor C. Then, the single-phase current will be processed by the voltage collection circuit 204 and the current processing circuit 205 to collect the single-phase current of the motor.

[0069] In addition, when the first complementary switch circuit 2021 controls the connection between the U-phase current output terminal and the first resistor R1, and the second complementary switch circuit 2022 controls the connection between the V-phase current output terminal and the second resistor R2, and the third complementary switch circuit 2023 controls the connection between the W-phase current output terminal and the target node O, the U-phase current outputted from the U-phase current output terminal flows through the first resistor R1 and flows to the third complementary switch circuit 2023; the V-phase current outputted from the V-phase current output terminal flows through the second resistor R2 and flows to the third complementary switch circuit 2023. In this case, the current of the third resistor R3 is 0. The voltage acquisition circuit 204 can be used to acquire the voltage between the first complementary switch circuit 2021 and the bus capacitor C, that is, to acquire the voltage between the U-phase current input terminal of the first resistor R1 and the U-phase current output terminal of the third resistor R3, so that the current processing circuit 205 can be used to convert the voltage into current and acquire the U-phase current.

[0070] The voltage acquisition circuit 204 can be used to collect the voltage between the second complementary switch circuit 2022 and the bus capacitor C, that is, to collect the voltage between the V-phase current input end of the second resistor R2 and the V-phase current output end of the third resistor R3, so that the current processing circuit 205 can be used to convert the voltage into current and collect the V-phase current.

[0071] It should be noted that the first phase current output terminal, the second phase current output terminal, and the third phase current output terminal can also be the V phase current output terminal, the W phase current output terminal, the U phase current output terminal, etc. respectively, and the embodiment of the present application is not limited to this.

[0072] In an embodiment of the present application, a current sampling circuit includes: a bus capacitor, a motor, an inverter circuit, a sampling circuit, a voltage acquisition circuit and a current processing circuit. The sampling circuit includes a first resistor, a second resistor and a third resistor. The inverter circuit includes a first complementary switch circuit, a second complementary switch circuit and a third complementary switch circuit. The first complementary switch circuit is connected to the first phase current output terminal of the motor and the first resistor, and is used to control the connection or disconnection of the first phase current output terminal and the first resistor. The second complementary switch circuit is also connected to the second phase current output terminal of the motor and the second resistor, and is used to control the connection or disconnection of the second phase current output terminal and the second resistor. The third complementary switch circuit is also connected to the third phase current output terminal of the motor and the target node, and is used to control the connection or disconnection of the third phase current output terminal and the target node, and the first resistor and the second resistor are connected to the bus capacitor through the target node and the third resistor. The voltage acquisition circuit is used to collect the voltage between each complementary switch circuit through the sampling circuit and the bus capacitor, so that the current processing circuit converts the voltage into current and outputs the current. In this technical solution, as long as there is a complementary switch circuit in the inverter circuit to control the connection, the voltage acquisition circuit can collect the phase current of the motor through the current processing circuit. The inverter circuit can often be in a state where at least one complementary switch circuit is controlled to be connected. Therefore, compared with the related art, there is no need to reserve a specific minimum sampling time, thereby improving the bus voltage utilization rate.

[0073] Alternatively, if Figure 3 As shown, the voltage acquisition circuit 204 includes a first operational amplifier U1 and a second operational amplifier U2. The first operational amplifier U1 is respectively connected to the first resistor R1, the third resistor R3 and the current processing circuit 205. The first operational amplifier U1 is used to amplify the voltage across the first resistor R1 and the third resistor R3, and output the amplified voltage to the current processing circuit 205.

[0074] The second operational amplifier U2 is respectively connected to the second resistor R2, the third resistor R3 and the current processing circuit 205. The second operational amplifier U2 is used to amplify the voltage across the second resistor R2 and the third resistor R3, and output the amplified voltage to the current processing circuit 205.

[0075] In this way, when only the first complementary switch circuit 2021 controls the connection between the first phase current output terminal and the first resistor R1, the first operational amplifier U1 can collect and amplify the voltage between the first phase current input terminal of the first resistor R1 and the first phase current output terminal of the third resistor R3, so that the current processing circuit 205 can convert the voltage into current and collect the first phase current output from the first phase current output terminal.

[0076] Similarly, when only the second complementary switch circuit 2022 controls the connection between the second phase current output terminal and the second resistor R2, the second operational amplifier U2 can collect and amplify the voltage between the second phase current input terminal of the second resistor R2 and the second phase current output terminal of the third resistor R3, so that the current processing circuit 205 can convert the voltage into current and collect the second phase current output from the second phase current output terminal.

[0077] Similarly, when only the third complementary switch circuit 2023 controls the connection between the third phase current output terminal and the target node O, the second operational amplifier U2 can collect and amplify the voltage across the second resistor R2 and the third resistor R3. However, since the current of the second resistor R2 is 0, it can be considered that the second operational amplifier U2 can collect and amplify the voltage across the third resistor R, so that the current processing circuit 205 can convert the voltage into current and collect the third phase current output by the third phase current output terminal.

[0078] In addition, when the first complementary switch circuit 2021 controls the connection between the first phase current output terminal and the first resistor R1, and the second complementary switch circuit 2022 controls the connection between the second phase current output terminal and the second resistor R2, and the third complementary switch circuit 2023 controls the connection between the third phase current output terminal and the target node O, the first operational amplifier U1 can collect and amplify the voltage across the first resistor R1 and the third resistor R3, so that the current processing circuit 205 can convert the voltage into current and collect the first phase current output from the first phase current output terminal. In addition, the second operational amplifier U2 can collect and amplify the voltage across the second resistor R2 and the third resistor R3, so that the current processing circuit 205 can convert the voltage into current and collect the second phase current output from the second phase current output terminal. It should be noted that since the current of the third resistor R3 is 0, it can be considered that the first operational amplifier U1 collects and amplifies the voltage across the first resistor R1. Similarly, it can be considered that the second operational amplifier U2 collects and amplifies the voltage across the second resistor R2.

[0079] In some embodiments of the present application, Figure 3As shown, the first complementary switch circuit 2021 includes a first transistor Q1 and a second transistor Q2 connected in series. The path between the first transistor Q1 and the second transistor Q2 is connected to the first phase current output terminal, the second transistor Q2 is connected to the first resistor R1, and the first transistor Q1 is connected to the bus capacitor C. The switching states of the first transistor Q1 and the second transistor Q2 are opposite, and are used to configure and control the connection or disconnection of the first phase current output terminal and the first resistor. Specifically, when the second transistor Q2 is turned on, the first phase current output terminal is connected to the first resistor; when the second transistor Q2 is turned off, the first phase current output terminal is disconnected from the first resistor.

[0080] The second complementary switch circuit 2022 includes a third transistor Q3 and a fourth transistor Q4 connected in series. The path between the third transistor Q3 and the fourth transistor Q4 is connected to the second phase current output terminal, the fourth transistor Q4 is connected to the second resistor R2, and the third transistor Q3 is connected to the bus capacitor C. The switching states of the third transistor Q3 and the fourth transistor Q4 are opposite, and are used to configure and control the second phase current output terminal to be connected or disconnected with the second resistor. Specifically, when the fourth transistor Q4 is turned on, the second phase current output terminal is connected to the second resistor; when the fourth transistor Q4 is turned off, the second phase current output terminal is disconnected from the second resistor.

[0081] The third complementary switch circuit 2023 includes a fifth transistor Q5 and a sixth transistor Q6 connected in series. The path between the fifth transistor Q5 and the sixth transistor Q6 is connected to the third phase current output terminal, the sixth transistor Q6 is connected to the target node O, and the fifth transistor Q5 is connected to the bus capacitor C. The switching states of the fifth transistor Q5 and the sixth transistor Q6 are opposite, and are used to configure and control the connection or disconnection of the third phase current output terminal and the target node. Specifically, when the sixth transistor Q6 is turned on, the third phase current output terminal is connected to the target node; when the sixth transistor Q6 is turned off, the third phase current output terminal is disconnected from the target node.

[0082] In an optional case, the second transistor Q2, the fourth transistor Q4 and the sixth transistor Q6 are all N-type metal oxide semiconductor field effect transistors (N-Metal-Oxide-Semiconductor, NMOS). Correspondingly, the first transistor Q1, the third transistor Q3 and the fifth transistor Q5 are all P-channel metal oxide semiconductor field effect transistors (Positivechannel Metal Oxide Semiconductor, PMOS). Of course, in some embodiments, the second transistor Q2, the fourth transistor Q4 and the sixth transistor Q6 are all PMOS tubes. Correspondingly, the first transistor Q1, the third transistor Q3 and the fifth transistor Q5 are all NMOS.

[0083] For example, the first phase current output terminal is the U phase current output terminal, the second phase current output terminal is the V phase current output terminal, and the third phase current output terminal is the W phase current output terminal. When at least one of the second transistor Q2, the fourth transistor Q4, and the sixth transistor Q6 is turned on, one phase current will flow through the resistors (the first resistor R1, the second resistor R2, and the third resistor R3) in the sampling circuit 203 to the bus capacitor C. Then, it is processed by the voltage acquisition circuit 204 and the current processing circuit 205 to acquire one phase current of the motor.

[0084] Specifically, when only the second transistor Q2 is turned on, the first phase current output terminal is connected to the first resistor R1. Figure 4 As shown, the U-phase current output terminal of the motor outputs the U-phase current, and the U-phase current passes through the second transistor Q2, flows through the first resistor R1, the third resistor R3 to the bus capacitor C. The first operational amplifier U1 can collect and amplify the voltage between the U-phase current input terminal of the first resistor R1 and the U-phase current output terminal of the third resistor R3, so that the current processing circuit 205 can convert the voltage into current and collect the U-phase current.

[0085] Similarly, when only the fourth transistor Q4 is turned on, the second phase current output terminal is connected to the second resistor R2. Figure 5 As shown, the V-phase current output terminal of the motor outputs the V-phase current, and the V-phase current passes through the fourth transistor Q4, flows through the second resistor R2, the third resistor R3 to the bus capacitor C. The second operational amplifier U2 can collect and amplify the voltage between the V-phase current input terminal of the second resistor R2 and the V-phase current output terminal of the third resistor R3, so that the current processing circuit 205 can convert the voltage into current and collect the V-phase current output from the second phase current output terminal.

[0086] Similarly, when only the sixth transistor Q6 is turned on, the third phase current output terminal is connected to the target node O. Figure 6 As shown, the W-phase current output terminal of the motor outputs the W-phase current, and the W-phase current passes through the sixth transistor Q6, flows through the third resistor R3 to the bus capacitor C. The second operational amplifier U2 can collect and amplify the voltage across the second resistor R2 and the third resistor R3, so that the current processing circuit 205 can convert the voltage into current and collect the W-phase current.

[0087] In addition, when the second transistor Q2, the fourth transistor Q4 and the sixth transistor Q6 are all turned on, the U-phase current output terminal is connected to the first resistor R1, the V-phase current output terminal is connected to the second resistor R2, and the W-phase current output terminal is connected to the target node O. Figure 7As shown, the U-phase current outputted from the U-phase current output terminal flows through the second transistor Q2 and the first resistor R1, and flows to the sixth transistor Q6; the V-phase current outputted from the V-phase current output terminal flows through the fourth transistor Q4 and the second resistor R2, and flows to the sixth transistor Q6. The first operational amplifier U1 can collect and amplify the voltage across the first resistor R1 and the third resistor R3, so that the current processing circuit 205 can convert the voltage into current and collect the U-phase current. In addition, the second operational amplifier U2 can collect and amplify the voltage across the second resistor R2 and the third resistor R3, so that the current processing circuit 205 can convert the voltage into current and collect the V-phase current. It should be noted that, since the current of the third resistor R3 is 0, it can be considered that the first operational amplifier U1 collects and amplifies the voltage across the first resistor R1. Similarly, it can be considered that the second operational amplifier U2 collects and amplifies the voltage across the second resistor R2.

[0088] In some embodiments of the present application, the current processing circuit may be a digital signal processor (DSP) or a general processor. The current processing circuit may be used to calculate the current corresponding to the voltage according to the voltage output by the voltage acquisition circuit and the resistance value of the sampling resistor corresponding to the voltage. Specifically, optionally, the voltage acquisition circuit 204 is used to collect the voltage between the U-phase current input terminal of the first resistor R1 and the U-phase current output terminal of the third resistor R3. Accordingly, the current processing circuit 205 may be used to calculate the U-phase current according to the received voltage and the series resistance of the first resistor R1 and the third resistor R3. Alternatively, the voltage acquisition circuit 204 is used to collect the voltage between the V-phase current input terminal of the second resistor R2 and the V-phase current output terminal of the third resistor R3. Accordingly, the current processing circuit 205 may be used to calculate the V-phase current according to the received voltage and the series resistance of the second resistor R2 and the third resistor R3. Alternatively, the voltage acquisition circuit 204 is used to collect the voltage between the two terminals of the third resistor R3. Accordingly, the current processing circuit 205 can be used to calculate the W-phase current according to the received voltage and the resistance value of the third resistor R3.

[0089] In an embodiment of the present application, a current sampling circuit includes: a bus capacitor, a motor, an inverter circuit, a sampling circuit, a voltage acquisition circuit and a current processing circuit. The sampling circuit includes a first resistor, a second resistor and a third resistor. The inverter circuit includes a first complementary switch circuit, a second complementary switch circuit and a third complementary switch circuit. The first complementary switch circuit is connected to the first phase current output terminal of the motor and the first resistor, and is used to control the connection or disconnection of the first phase current output terminal and the first resistor. The second complementary switch circuit is also connected to the second phase current output terminal of the motor and the second resistor, and is used to control the connection or disconnection of the second phase current output terminal and the second resistor. The third complementary switch circuit is also connected to the third phase current output terminal of the motor and the target node, and is used to control the connection or disconnection of the third phase current output terminal and the target node, and the first resistor and the second resistor are connected to the bus capacitor through the target node and the third resistor. The voltage acquisition circuit is used to collect the voltage between each complementary switch circuit through the sampling circuit and the bus capacitor, so that the current processing circuit converts the voltage into current and outputs the current. In this technical solution, as long as there is a complementary switch circuit in the inverter circuit to control the connection, the voltage acquisition circuit can collect the phase current of the motor through the current processing circuit. The inverter circuit can often be in a state where at least one complementary switch circuit is controlled to be connected. Therefore, compared with the related art, there is no need to reserve a specific minimum sampling time, thereby improving the bus voltage utilization rate.

[0090] Please refer to Figure 8 , which shows a flow chart of a current reconstruction method provided in an embodiment of the present application. In an optional case, the current reconstruction method can be applied to a motor current reconstruction system. The motor current reconstruction system includes a current sampling circuit provided in an embodiment of the present application, and a reconstruction calculation unit connected to the current sampling circuit. The current reconstruction method can be executed by the reconstruction calculation unit. In another optional case, the current reconstruction method can be applied to the current sampling circuit provided in an embodiment of the present application, and executed by a current processing circuit. The following embodiments illustrate the current reconstruction method by the reconstruction calculation unit as an example. Of course, the current reconstruction method provided in an embodiment of the present application can also be processed by other devices connected to the current sampling circuit provided in an embodiment of the present application, which is not limited here. Figure 8 As shown, the current reconstruction method includes:

[0091] Step 801 : When the motor is located in any target sector of a plurality of sectors, target on-off states of a first complementary switch circuit, a second complementary switch circuit and a third complementary switch circuit in a current sampling circuit are collected.

[0092] Among them, the sectors of the motor are used to describe the spatial position of the stator flux and the voltage vector. The space of the motor can be divided into 6 sectors or 12 sectors, etc. In an embodiment of the present application, the reconstruction calculation unit can respectively execute the current reconstruction method provided in the embodiment of the present application when the motor is located in each sector to obtain the three-phase current corresponding to the motor in each sector. Optionally, the reconstruction calculation unit can obtain the current rotor position of the motor, and then determine the target sector where the motor is currently located according to the current rotor position of the motor.

[0093] For example, please refer to Fig. 9 , which shows a six-sector schematic diagram of a motor provided in an embodiment of the present application. Fig. 9 Ⅰ, Ⅱ, Ⅲ, Ⅳ, Ⅴ, Ⅵ represent the first to sixth sectors respectively. In addition, Fig. 9 The area enclosed by the middle dotted line and the outer edge of the hexagon is the non-modulation area of ​​the dual-resistance sampling circuit, also known as the dual-resistance sampling minimum opening time limit area.

[0094] In the embodiment of the present application, the reconstruction calculation unit can collect the target on-off state of the first complementary switch circuit, the second complementary switch circuit, and the third complementary switch circuit in real time, so as to subsequently determine whether the on-off state corresponding to the target sampling time of the target sector is reached. The target on-off state is used to indicate whether the first complementary switch circuit, the second complementary switch circuit, and the third complementary switch circuit are currently in the on state or the off state.

[0095] In some embodiments of the present application, the first complementary switch circuit, the second complementary switch circuit and the third complementary switch circuit in the inverter circuit are used to be periodically turned on or off under the control of the motor control circuit, so that the first complementary switch circuit periodically controls the connection or disconnection between the first phase current output terminal and the first resistor, the second complementary switch circuit periodically controls the connection or disconnection between the second phase current output terminal and the second resistor, and the third complementary switch circuit periodically controls the connection or disconnection between the third phase current output terminal and the target node.

[0096] Based on this, the reconstruction calculation unit can obtain the current target on-off state of the first complementary switch circuit, the second complementary switch circuit and the third complementary switch circuit through the motor control circuit. In an optional case, during the operation of the motor, the motor control circuit can control the first complementary switch circuit, the second complementary switch circuit and the third complementary switch circuit in the inverter circuit to periodically turn on or off according to the current size and direction of the three-phase current of the motor.

[0097] Optionally, when the current sampling circuit includes a first transistor, a second transistor, a third transistor, a fourth transistor, a fifth transistor and a sixth transistor, the first transistor and the second transistor, the third transistor, the fourth transistor, the fifth transistor and the sixth transistor are used to be periodically turned on or off under the control of the motor control circuit.

[0098] Since the switch states of the first transistor and the second transistor are opposite, the switch states of the third transistor and the fourth transistor are opposite, and the switch states of the fifth transistor and the sixth transistor are opposite. Therefore, the reconstruction calculation unit can only collect the target channel states of the second transistor, the fourth transistor and the sixth transistor, thereby reducing the amount of collected data. For example, the reconstruction calculation unit can obtain the current target on-off states of the second transistor, the fourth transistor and the sixth transistor through the motor control circuit.

[0099] Step 802: based on the target correspondence between the on-off state of the sector, the first complementary switch circuit, the second complementary switch circuit, and the third complementary switch circuit and the target sampling time, and the target on-off state, upon determining the on-off state corresponding to the target sampling time of reaching the target sector, collect the voltage output by the voltage collection circuit at the target sampling time.

[0100] In some embodiments of the present application, after the reconstruction calculation unit collects the target on-off states of the first complementary switch circuit, the second complementary switch circuit, and the third complementary switch circuit, it can determine the first on-off state corresponding to the target sampling time under the target sector according to the target correspondence between the on-off states of the sector, the first complementary switch circuit, the second complementary switch circuit, and the third complementary switch circuit and the target sampling time.

[0101] The reconstruction calculation unit determines whether the target on-off state matches the first on-off state. If the target on-off state matches the first on-off state, the on-off state corresponding to the target sampling time of reaching the target sector is determined. If the target on-off state does not match the first on-off state, the reconstruction calculation unit can return to execute step 103 to re-collect the target on-off states of the first complementary switch circuit, the second complementary switch circuit, and the third complementary switch circuit.

[0102] The reconstruction calculation unit collects the voltage output by the voltage acquisition circuit at the target sampling time when determining the on-off state corresponding to the target sampling time when the target sector is reached. The target sampling time may refer to a certain moment within the on-off cycle of the first complementary switch circuit, the second complementary switch circuit, and the third complementary switch circuit. It is not difficult to understand that the reconstruction calculation unit collects the voltage output by the voltage acquisition circuit at the target sampling time within the current on-off cycle of the first complementary switch circuit, the second complementary switch circuit, and the third complementary switch circuit when determining the on-off state corresponding to the target sampling time when the target sector is reached.

[0103] In an optional case, when the voltage acquisition circuit includes a first operational amplifier and a second operational amplifier, when determining the on-off state corresponding to the target sampling moment of reaching the target sector, the process of acquiring the voltage output by the voltage acquisition circuit at the target sampling moment may include: when determining the on-off state corresponding to the target sampling moment of reaching the target sector, acquiring the first voltage output by the first operational amplifier at the target sampling moment, and acquiring the second voltage output by the second operational amplifier at the target sampling moment.

[0104] In an optional implementation, the target sampling moment in the target correspondence is a moment determination function. Accordingly, when the reconstruction calculation unit determines the on-off state corresponding to the target sampling moment of reaching the target sector, the process of collecting the first voltage output by the first operational amplifier at the target sampling moment and collecting the second voltage output by the second operational amplifier at the target sampling moment may include:

[0105] When the on-off state corresponding to the target sampling time of reaching the target sector is determined, a time determination function corresponding to the target on-off state in the target corresponding relationship is obtained. According to the time determination function, the target sampling time in the switching cycle is calculated. The first voltage output by the first operational amplifier at the target sampling time is collected, and the second voltage output by the second operational amplifier at the target sampling time is collected.

[0106] Among them, the moment determination function indicates the correlation between the target sampling moment and the switching cycle of the complementary switch circuit. For example, the moment determination function can be T1=(T-Tb) / 2+Tmin, T1 represents the target sampling moment, and T represents the switching cycle (i.e., the on-off cycle) of the complementary switch circuit. Tb represents the turn-on time of the lower bridge of the second complementary switch circuit in the inverter circuit. Tmin represents the custom sampling time, which is usually a custom value. In this way, the reconstruction calculation unit can determine the target sampling moment T1. When the reconstruction calculation unit determines the on-off state corresponding to the target sampling moment of reaching the target sector, it starts calculating from the starting moment of the current on-off cycle of the complementary switch circuit, and when it is determined that the target sampling moment T1 is reached, the first voltage output by the first operational amplifier at the target sampling moment is collected, and the second voltage output by the second operational amplifier at the target sampling moment is collected.

[0107] In some embodiments of the present application, the current sampling circuit includes a first transistor, a second transistor, a third transistor, a fourth transistor, a fifth transistor, and a sixth transistor. As described above, the process in which the reconstruction calculation unit can collect the target on-off state of the first complementary switch circuit, the second complementary switch circuit, and the third complementary switch circuit in the current sampling circuit may include: collecting the target on-off state of the second transistor, the fourth transistor, and the sixth transistor. The target on-off state indicates that the second transistor, the fourth transistor, and the sixth transistor are in an on or off state.

[0108] Accordingly, the target correspondence between the on-off states of the sectors, the first complementary switch circuit, the second complementary switch circuit and the third complementary switch circuit and the target sampling time includes: the target correspondence between the on-off states of the sectors, the second transistor, the fourth transistor and the sixth transistor and the target sampling time.

[0109] For example, the target correspondence may be recorded in a table. Assume that the first phase current output terminal is a U phase current output terminal, the second phase current output terminal is a V phase current output terminal, and the third phase current output terminal is a W phase current output terminal.

[0110] As shown in Table 1, the target corresponding relationship includes: the on-off state 110 of the second transistor, the fourth transistor and the sixth transistor corresponding to the first sector, the target sampling time T11; the on-off state 110 of the second transistor, the fourth transistor and the sixth transistor corresponding to the second sector, the target sampling time T21; the on-off state 011 of the second transistor, the fourth transistor and the sixth transistor corresponding to the third sector, the target sampling time T31; the on-off state 011 of the second transistor, the fourth transistor and the sixth transistor corresponding to the fourth sector, the target sampling time T41; the on-off state 101 of the second transistor, the fourth transistor and the sixth transistor corresponding to the fifth sector, the target sampling time T51; the on-off state 101 of the second transistor, the fourth transistor and the sixth transistor corresponding to the sixth sector, the target sampling time T61, etc. It should be noted that in Table 1, Q2 represents the second transistor, Q4 represents the fourth transistor, Q6 represents the sixth transistor, 0 represents the transistor is disconnected, 1 represents the transistor is turned on, and T1 represents the target sampling time. Taking the on-off state 100 of the second transistor, the fourth transistor and the sixth transistor as an example, the on-off state indicates that the second transistor is in the on state, the fourth transistor is in the off state, and the sixth transistor is in the off state.

[0111]

[0112]

[0113] Table 1

[0114] Wherein, in the first sector, T1=T11=(T-Tb) / 2+Tmin. In the second sector, T1=T21=(T-Ta) / 2+Tmin. In the third sector, T1=T31=(T-Tc) / 2+Tmin. In the fourth sector, T1=T41=(T-Tb) / 2+Tmin. In the fifth sector, T1=T51=(T-Ta) / 2+Tmin. In the sixth sector, T1=T61=(T-Tc) / 2+Tmin. Wherein, T represents the switching period of the transistor (i.e., the on-off period of the complementary switching circuit), and the switching periods of the first transistor, the second transistor, the third transistor, the fourth transistor, the fifth transistor and the sixth transistor are equal. Tb represents the turn-on time of the fourth transistor of the lower bridge in the inverter circuit (i.e., the turn-on time of the lower bridge of the second complementary switching circuit). Ta represents the turn-on time of the second transistor of the lower bridge in the inverter circuit (i.e., the turn-on time of the lower bridge of the first complementary switching circuit). Tc represents the turn-on time of the sixth transistor of the lower bridge in the inverter circuit (ie, the turn-on time of the lower bridge of the third complementary switch circuit). Tmin represents the custom sampling time, which is usually a custom value.

[0115] It should be noted that you can also refer to Figures 10 to 15 , Figures 10 to 15 Schematic diagrams show the on or off states of the lower bridge transistor (i.e., the second transistor) of the U-phase current, the lower bridge transistor (i.e., the third transistor) of the V-phase current, and the lower bridge transistor (i.e., the fourth transistor) of the W-phase current in the first sector to the sixth sector respectively within a single switching cycle of the transistor. Figures 10 to 15 In the figure, 0 indicates that the transistor is in the off state, 1 indicates that the transistor is in the on state, U indicates the second transistor, V indicates the fourth transistor, and W indicates the sixth transistor.

[0116] by Fig.10 Take an example for explanation. When the motor is in the first sector, the motor control circuit controls the second transistor to be in the on state, the fourth transistor to be in the off-on-off state, and the sixth transistor to be in the off state within a single switching cycle of the transistor. The target correspondence relationship includes: the on-off state 110 of the second transistor, the fourth transistor and the sixth transistor corresponding to the first sector, and the target sampling time T11. The reconstruction calculation unit determines that the on-off state corresponding to the second sampling time under the first sector is reached, and reads the target sampling time T11 in the target correspondence relationship. The reconstruction calculation unit starts calculating from the starting time of the single switching cycle, and when it is determined that the target sampling time T11 is reached, the first voltage output by the first operational amplifier at the target sampling time is collected, and the second voltage output by the second operational amplifier at the target sampling time is collected.

[0117] Step 803: construct the three-phase current corresponding to the target sector according to the voltage, the resistance value of the first resistor, the resistance value of the second resistor and the resistance value of the third resistor, and obtain the three-phase current corresponding to each sector.

[0118] In some embodiments of the present application, the reconstruction calculation unit can construct the three-phase current corresponding to the target sector according to the voltage, the resistance value of the first resistor, the resistance value of the second resistor and the resistance value of the third resistor, and the process of obtaining the three-phase current corresponding to each sector may include: according to the corresponding relationship between the sector, the conversion relationship of the first phase current, the conversion relationship of the second phase current and the conversion relationship of the third phase current, determine the target conversion relationship of the first phase current, the target conversion relationship of the second phase current and the target conversion relationship of the third phase current corresponding to the target sector. According to the target conversion relationship, the three-phase current corresponding to the target sector is converted according to the voltage, the resistance value of the first resistor, the resistance value of the second resistor and the resistance value of the third resistor.

[0119] Among them, the conversion relationship of the first phase current can indicate the conversion relationship between the voltage, the resistance value of the first resistor, the resistance value of the second resistor, and the resistance value of the third resistor and the first phase current. The conversion relationship of the second phase current indicates the conversion relationship between the voltage, the resistance value of the first resistor, the resistance value of the second resistor, and the resistance value of the third resistor. The conversion relationship of the third phase current indicates the conversion relationship between the voltage, the resistance value of the first resistor, the resistance value of the second resistor, and the resistance value of the third resistor.

[0120] Optionally, when the voltage acquisition circuit includes a first operational amplifier and a second operational amplifier, the reconstruction calculation unit can, after determining the target conversion relationship for the first phase current, the target conversion relationship for the second phase current and the target conversion relationship for the third phase current corresponding to the target sector, obtain the three-phase current corresponding to the target sector according to the first voltage, the second voltage, the resistance value of the first resistor, the resistance value of the second resistor and the resistance value of the third resistor, and obtain the three-phase current corresponding to each sector.

[0121] Among them, the conversion relationship of the first phase current can indicate the conversion relationship between the first voltage / second voltage, the resistance value of the first resistor, the resistance value of the second resistor, and the resistance value of the third resistor and the first phase current. The conversion relationship of the second phase current indicates the conversion relationship between the first voltage / second voltage, the resistance value of the first resistor, the resistance value of the second resistor, and the resistance value of the third resistor. The conversion relationship of the third phase current indicates the conversion relationship between the first voltage / second voltage, the resistance value of the first resistor, the resistance value of the second resistor, and the resistance value of the third resistor.

[0122] Specifically, optionally, the reconstruction calculation unit may pre-store a correspondence between sectors, a conversion relation of the first phase current, a conversion relation of the second phase current, and a conversion relation of the third phase current. From the correspondence, the conversion relation of the first phase current, the conversion relation of the second phase current, and the conversion relation of the third phase current corresponding to the target sector are searched to obtain a target conversion relation of the first phase current, a target conversion relation of the second phase current, and a target conversion relation of the third phase current.

[0123] The reconstruction calculation unit converts the first phase current corresponding to the target sector according to the first voltage, the second voltage, the resistance value of the first resistor, the resistance value of the second resistor and the resistance value of the third resistor according to the target conversion relationship of the first phase current; converts the second phase current corresponding to the target sector according to the first voltage, the second voltage, the resistance value of the first resistor, the resistance value of the second resistor and the resistance value of the third resistor according to the target conversion relationship of the second phase current; and converts the third phase current corresponding to the target sector according to the first voltage, the second voltage, the resistance value of the first resistor, the resistance value of the second resistor and the resistance value of the third resistor according to the target conversion relationship of the third phase current.

[0124] For example, it is assumed that the first phase current output terminal is a U phase current output terminal, the second phase current output terminal is a V phase current output terminal, and the third phase current output terminal is a W phase current output terminal.

[0125] In the corresponding relationship among the sectors, the conversion relation of the first phase current, the conversion relation of the second phase current and the conversion relation of the third phase current, the conversion relation of the U phase current corresponding to the first sector satisfies Ia=-V2 / (R1+R3), the conversion relation of the V phase current satisfies Ib=-V1 / (R2+R3), and the conversion relation of the W phase current satisfies Ic=-(Ia+Ib);

[0126] The conversion relationship of the U-phase current corresponding to the second sector satisfies Ia=-V2 / (R1+R3), the conversion relationship of the V-phase current satisfies Ib=-V1 / (R2+R3), and the conversion relationship of the W-phase current satisfies Ic=-(Ia+Ib);

[0127] The conversion relationship of the U-phase current corresponding to the third sector satisfies Ia=-(Ib+Ic), the conversion relationship of the V-phase current satisfies Ib=-(V1-V2) / R2, and the conversion relationship of the W-phase current satisfies Ic=-(V2 / R2-Ib);

[0128] The conversion relationship of the U-phase current corresponding to the fourth sector satisfies Ia=-(Ib+Ic), the conversion relationship of the V-phase current satisfies Ib=-(V1-V2) / R2, and the conversion relationship of the W-phase current satisfies -(V2 / R2-Ib);

[0129] The conversion relationship of the U-phase current corresponding to the fifth sector satisfies Ia=-(V2-V1) / R1, the conversion relationship of the V-phase current satisfies Ib=-(Ia+Ic), and the conversion relationship of the W-phase current satisfies Ic=-(V1 / R1-Ia);

[0130] The conversion relationship of the U-phase current corresponding to the sixth sector satisfies Ia=-(V2-V1) / R1, the conversion relationship of the V-phase current satisfies Ib=-(Ia+Ic), and the conversion relationship of the W-phase current satisfies Ic=-(V1 / R1-Ia).

[0131] In the above conversion relationship, Ia represents the U phase current. Ib represents the V phase current. Ic represents the W phase current. V1 represents the first voltage output by the first operational amplifier. V2 represents the second voltage output by the second operational amplifier. R1 represents the resistance value of the first resistor. R2 represents the resistance value of the second resistor. R3 represents the resistance value of the third resistor.

[0132] For example, the resistance values ​​of the first resistor, the second resistor and the third resistor may be the same. Based on this, S represents the sector number, such as S=1 represents the first sector; S=2 represents the second sector, etc. The conversion relationship between the U-phase current, the V-phase current and the W-phase current in the first sector to the sixth sector can be more intuitively expressed as:

[0133] When S=1, Ia=-V2 / (2×R), Ib=-V1 / (2×R), Ic=-(Ia+Ib);

[0134] When S = 2, Ia = -V2 / (2×R), Ib = -V1 / (2×R), Ic = -(Ia+Ib);

[0135] When S=3, Ib=-(V1-V2) / R, Ic=-(V2 / R-Ib), Ia=-(Ib+Ic);

[0136] When S=4, Ib=-(V1-V2) / R, Ic=-(V2 / R-Ib), Ia=-(Ib+Ic);

[0137] When S=5, Ia=-(V2-V1) / R, Ic=-(V1 / R-Ia), Ib=-(Ia+Ic);

[0138] When S=6, Ia=-(V2-V1) / R, Ic=-(V1 / R-Ia), Ib=-(Ia+Ic).

[0139] In an embodiment of the present application, a current sampling circuit includes: a bus capacitor, a motor, an inverter circuit, a sampling circuit, a voltage acquisition circuit and a current processing circuit. The sampling circuit includes a first resistor, a second resistor and a third resistor. The inverter circuit includes a first complementary switch circuit, a second complementary switch circuit and a third complementary switch circuit. The first complementary switch circuit is connected to the first phase current output terminal of the motor and the first resistor, and is used to control the connection or disconnection of the first phase current output terminal and the first resistor. The second complementary switch circuit is also connected to the second phase current output terminal of the motor and the second resistor, and is used to control the connection or disconnection of the second phase current output terminal and the second resistor. The third complementary switch circuit is also connected to the third phase current output terminal of the motor and the target node, and is used to control the connection or disconnection of the third phase current output terminal and the target node, and the first resistor and the second resistor are connected to the bus capacitor through the target node and the third resistor. The voltage acquisition circuit is used to collect the voltage between each complementary switch circuit through the sampling circuit and the bus capacitor, so that the current processing circuit converts the voltage into current and outputs the current. In this technical solution, as long as there is a complementary switch circuit in the inverter circuit to control the connection, the voltage acquisition circuit can collect the phase current of the motor through the current processing circuit. The inverter circuit can often be in a state where at least one complementary switch circuit is controlled to be connected. Therefore, compared with the related art, there is no need to reserve a specific minimum sampling time, which improves the bus voltage utilization rate. By using the current sampling circuit to sample the three-phase current of each sector, the effective sampling of the motor three-phase current can be achieved on the basis of improving the bus voltage utilization rate.

[0140] Please refer to Fig.16 , which shows a block diagram of a current reconstruction device provided in an embodiment of the present application. The current reconstruction device is provided with a current sampling circuit provided in an embodiment of the present application. Fig.16 As shown, the current reconstruction device 1600 includes: a collection module 1601 and a construction module 1602 .

[0141] The acquisition module 1601 is used to acquire the target on-off states of the first complementary switch circuit, the second complementary switch circuit and the third complementary switch circuit in the current sampling circuit when the motor is located in any target sector of the multiple sectors;

[0142] The acquisition module 1601 is further used to acquire the voltage output by the voltage acquisition circuit at the target sampling time when the on-off state corresponding to the target sampling time of reaching the target sector is determined according to the target corresponding relationship between the on-off state of the sector, the first complementary switch circuit, the second complementary switch circuit, and the third complementary switch circuit and the target sampling time, and the target on-off state;

[0143] The construction module 1602 is used to construct the three-phase current corresponding to the target sector according to the voltage, the resistance value of the first resistor, the resistance value of the second resistor and the resistance value of the third resistor, so as to obtain the three-phase current corresponding to each sector.

[0144] Optionally, the voltage acquisition circuit includes a first operational amplifier and a second operational amplifier. The acquisition module 1601 is further used to: when determining the on-off state corresponding to the target sampling time of reaching the target sector, acquire the first voltage output by the first operational amplifier at the target sampling time, and acquire the second voltage output by the second operational amplifier at the target sampling time.

[0145] Optionally, the target sampling time in the target correspondence is a time determination function. The acquisition module 1601 is also used for:

[0146] In the case of determining the on-off state corresponding to the target sampling moment of reaching the target sector, obtaining a time determination function corresponding to the target on-off state in the target corresponding relationship, the time determination function indicating the correlation between the target sampling moment and the switching cycle of the complementary switch circuit;

[0147] Determine the target sampling time in the switching cycle according to the time determination function;

[0148] A first voltage output by the first operational amplifier at a target sampling time is collected, and a second voltage output by the second operational amplifier at a target sampling time is collected.

[0149] Optionally, the current sampling circuit includes a first transistor, a second transistor, a third transistor, a fourth transistor, a fifth transistor and a sixth transistor. The target correspondence between the on-off state of the sector, the first complementary switch circuit, the second complementary switch circuit and the third complementary switch circuit and the target sampling time includes: the target correspondence between the on-off state of the sector, the second transistor, the fourth transistor and the sixth transistor and the target sampling time.

[0150] The acquisition module 1601 is further used to: acquire the target on-off states of the second transistor, the fourth transistor and the sixth transistor.

[0151] Optionally, the building block 1602 is further configured to:

[0152] Determine the target conversion relation of the first phase current, the target conversion relation of the second phase current, and the target conversion relation of the third phase current corresponding to the target sector according to the corresponding relationship among the sectors, the conversion relation of the first phase current, the conversion relation of the second phase current, and the conversion relation of the third phase current;

[0153] According to the target conversion relationship, the three-phase current corresponding to each sector is obtained by conversion based on the voltage, the resistance value of the first resistor, the resistance value of the second resistor and the resistance value of the third resistor.

[0154] In an embodiment of the present application, a current sampling circuit includes: a bus capacitor, a motor, an inverter circuit, a sampling circuit, a voltage acquisition circuit and a current processing circuit. The sampling circuit includes a first resistor, a second resistor and a third resistor. The inverter circuit includes a first complementary switch circuit, a second complementary switch circuit and a third complementary switch circuit. The first complementary switch circuit is connected to the first phase current output terminal of the motor and the first resistor, and is used to control the connection or disconnection of the first phase current output terminal and the first resistor. The second complementary switch circuit is also connected to the second phase current output terminal of the motor and the second resistor, and is used to control the connection or disconnection of the second phase current output terminal and the second resistor. The third complementary switch circuit is also connected to the third phase current output terminal of the motor and the target node, and is used to control the connection or disconnection of the third phase current output terminal and the target node, and the first resistor and the second resistor are connected to the bus capacitor through the target node and the third resistor. The voltage acquisition circuit is used to collect the voltage between each complementary switch circuit through the sampling circuit and the bus capacitor, so that the current processing circuit converts the voltage into current and outputs the current. In this technical solution, as long as there is a complementary switch circuit in the inverter circuit to control the connection, the voltage acquisition circuit can collect the phase current of the motor through the current processing circuit. The inverter circuit can often be in a state where at least one complementary switch circuit is controlled to be connected. Therefore, compared with the related art, there is no need to reserve a specific minimum sampling time, thereby improving the bus voltage utilization rate. The current reconstruction device can effectively sample the three-phase current of the motor on the basis of improving the bus voltage utilization rate by using the current sampling circuit to sample the three-phase current of each sector.

[0155] The embodiment of the present application also provides an electronic device, which may include the current sampling circuit provided by the embodiment of the present application. Thus, in the electronic device provided by the embodiment of the present application, the current sampling circuit includes: a bus capacitor, a motor, an inverter circuit, a sampling circuit, a voltage acquisition circuit and a current processing circuit. The sampling circuit includes a first resistor, a second resistor and a third resistor. The inverter circuit includes a first complementary switch circuit, a second complementary switch circuit and a third complementary switch circuit. The first complementary switch circuit is connected to the first phase current output terminal of the motor and the first resistor, and is used to control the connection or disconnection of the first phase current output terminal and the first resistor. The second complementary switch circuit is also connected to the second phase current output terminal of the motor and the second resistor, and is used to control the connection or disconnection of the second phase current output terminal and the second resistor. The third complementary switch circuit is also connected to the third phase current output terminal of the motor and the target node, and is used to control the connection or disconnection of the third phase current output terminal and the target node, and the first resistor and the second resistor are connected to the bus capacitor through the target node and the third resistor. The voltage acquisition circuit is used to collect the voltage between each complementary switch circuit through the sampling circuit and the bus capacitor, so that the current processing circuit converts the voltage into current and outputs the current. In this technical solution, as long as there is a complementary switch circuit in the inverter circuit that controls the connection, the voltage acquisition circuit can collect the phase current of the motor through the current processing circuit. The inverter circuit can often be in a state where at least one complementary switch circuit controls the connection. Therefore, compared with the related art, there is no need to reserve a specific minimum sampling time to improve the bus voltage utilization rate. The current reconstruction device uses the current sampling circuit to sample the three-phase current of each sector, and can achieve effective sampling of the motor three-phase current on the basis of improving the bus voltage utilization rate.

[0156] Optionally, the electronic device may further include a processor and a memory. The memory is used to store a computer program. The processor is used to implement the control method of the driver chip in the method embodiment of the present application when executing the program stored in the memory.

[0157] The embodiment of the present application also provides a readable storage medium, on which a program or instruction is stored, and when the program or instruction is executed by a processor, the control method of the above-mentioned driver chip is implemented. Wherein, the processor is the processor in the electronic device in the above-mentioned embodiment. The readable storage medium includes a computer-readable storage medium, such as a computer read-only memory (ROM), a random access memory (RAM), a disk or an optical disk, etc.

[0158] The embodiments of the present application are described above in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present application, ordinary technicians in this field can also make many forms without departing from the purpose of the present application and the scope of protection of the claims, all of which are within the protection of the present application.

Claims

1. A current sampling circuit, characterized in that: The current sampling circuit comprises: a bus capacitor, a motor, an inverter circuit, a sampling circuit, a voltage acquisition circuit and a current processing circuit; The sampling circuit includes a first resistor, a second resistor and a third resistor, the inverter circuit includes a first complementary switch circuit, a second complementary switch circuit and a third complementary switch circuit, all of which are connected to the bus capacitor, the first complementary switch circuit is also connected to the first phase current output end of the motor and the first resistor, and is used to control the connection or disconnection of the first phase current output end and the first resistor; The second complementary switch circuit is also connected to the second phase current output terminal of the motor and the second resistor, and is used to control the connection or disconnection between the second phase current output terminal and the second resistor; The third complementary switch circuit is also connected to the third phase current output terminal of the motor and the target node, and is used to control the connection or disconnection between the third phase current output terminal and the target node, and the first resistor and the second resistor are connected to the bus capacitor through the target node and the third resistor; The voltage collection circuit is connected to the sampling circuit and is used to collect the voltage between each complementary switch circuit through the sampling circuit and the bus capacitor; The current processing circuit is connected to the voltage acquisition circuit, and is used for converting the voltage into current and outputting the current.

2. The current sampling circuit according to claim 1, characterized in that: The voltage acquisition circuit includes a first operational amplifier and a second operational amplifier; The first operational amplifier is connected to the first resistor, the third resistor and the current processing circuit respectively, and is used to amplify the voltage across the first resistor and the third resistor, and output the amplified voltage to the current processing circuit; The second operational amplifier is connected to the second resistor, the third resistor and the current processing circuit respectively, and is used to amplify the voltage across the second resistor and the third resistor, and output the amplified voltage to the current processing circuit.

3. The current sampling circuit according to claim 1 or 2, characterized in that: The first complementary switch circuit includes a first transistor and a second transistor connected in series, a path between the first transistor and the second transistor is connected to the first phase current output terminal, and the second transistor is connected to the first resistor; The second complementary switch circuit comprises a third transistor and a fourth transistor connected in series, a path between the third transistor and the fourth transistor is connected to the second phase current output terminal, and the fourth transistor is connected to the second resistor; The third complementary switch circuit includes a fifth transistor and a sixth transistor connected in series, the path between the fifth transistor and the sixth transistor is connected to the third phase current output terminal, the sixth transistor is connected to the target node, the first transistor, the third transistor and the fifth transistor are all connected to the bus capacitor, the first phase current output terminal is the U phase current output terminal, the second phase current output terminal is the V phase current output terminal, and the third phase current output terminal is the W phase current output terminal.

4. A current reconstruction method, characterized in that: Applied to the current sampling circuit according to any one of claims 1 to 3, the method comprises: When the motor is located in any target sector of the plurality of sectors, collecting target on-off states of the first complementary switch circuit, the second complementary switch circuit, and the third complementary switch circuit in the current sampling circuit; According to the target corresponding relationship between the on-off state of the sector, the first complementary switch circuit, the second complementary switch circuit, and the third complementary switch circuit and the target sampling time, and the target on-off state, when the on-off state corresponding to the target sampling time reaching the target sector is determined, the voltage output by the voltage acquisition circuit at the target sampling time is acquired; The three-phase current corresponding to the target sector is constructed according to the voltage, the resistance value of the first resistor, the resistance value of the second resistor and the resistance value of the third resistor, so as to obtain the three-phase current corresponding to each of the sectors.

5. The method according to claim 4, characterized in that The voltage acquisition circuit includes the first operational amplifier and the second operational amplifier; and when the on-off state corresponding to the target sampling moment of reaching the target sector is determined, acquiring the voltage output by the voltage acquisition circuit at the target sampling moment includes: When the on / off state corresponding to the target sampling time at which the target sector is reached is determined, a first voltage output by the first operational amplifier at the target sampling time is collected, and a second voltage output by the second operational amplifier at the target sampling time is collected.

6. The method according to claim 5, characterized in that The target sampling time in the target corresponding relationship is a time determination function, and when the on-off state corresponding to the target sampling time of reaching the target sector is determined, a first voltage output by the first operational amplifier at the target sampling time is collected, and a second voltage output by the second operational amplifier at the target sampling time is collected, including: In the case of determining the on-off state corresponding to the target sampling moment of reaching the target sector, obtaining a time determination function corresponding to the target on-off state in the target corresponding relationship, the time determination function indicating the correlation between the target sampling moment and the switching cycle of the complementary switching circuit; Determine a target sampling time within the switching cycle according to the time determination function; A first voltage output by the first operational amplifier at the target sampling time is collected, and a second voltage output by the second operational amplifier at the target sampling time is collected.

7. The method according to claim 4, characterized in that The current sampling circuit includes a first transistor, a second transistor, a third transistor, a fourth transistor, a fifth transistor and a sixth transistor; the collecting of the target on-off states of the first complementary switch circuit, the second complementary switch circuit and the third complementary switch circuit in the current sampling circuit includes: collecting the target on-off states of the second transistor, the fourth transistor and the sixth transistor; The target correspondence between the on-off state of the sector, the first complementary switch circuit, the second complementary switch circuit and the third complementary switch circuit and the target sampling time includes: the target correspondence between the on-off state of the sector, the second transistor, the fourth transistor and the sixth transistor and the target sampling time.

8. The method according to claim 4, characterized in that The constructing the three-phase current corresponding to the target sector according to the voltage, the resistance value of the first resistor, the resistance value of the second resistor and the resistance value of the third resistor to obtain the three-phase current corresponding to each of the sectors includes: Determine the target conversion relation of the first phase current, the target conversion relation of the second phase current, and the target conversion relation of the third phase current corresponding to the target sector according to the corresponding relationship among the sectors, the conversion relation of the first phase current, the conversion relation of the second phase current, and the conversion relation of the third phase current; According to the target conversion relationship, the three-phase current corresponding to each sector is obtained by converting the voltage, the resistance value of the first resistor, the resistance value of the second resistor and the resistance value of the third resistor.

9. A current reconstruction device, characterized in that: The current reconstruction device is provided with a current sampling circuit according to any one of claims 1 to 3, and the device comprises: a collection module, configured to collect target on-off states of the first complementary switch circuit, the second complementary switch circuit, and the third complementary switch circuit in the current sampling circuit when the motor is located in any target sector of the plurality of sectors; The acquisition module is further configured to acquire the voltage output by the voltage acquisition circuit at the target sampling time when the on-off state corresponding to the target sampling time at which the target sector is reached is determined, based on the target corresponding relationship between the on-off state of the sector, the first complementary switch circuit, the second complementary switch circuit, and the third complementary switch circuit and the target sampling time, and the target on-off state; A construction module is used to construct the three-phase current corresponding to the target sector according to the voltage, the resistance value of the first resistor, the resistance value of the second resistor and the resistance value of the third resistor, so as to obtain the three-phase current corresponding to each of the sectors.

10. A computer device, characterized in that: include: A processor, a memory and a current sampling circuit as claimed in any one of claims 1 to 3; The memory is used to store computer programs; The processor is used to implement the method described in any one of claims 4 to 8 when executing the program stored in the memory.

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