A motor phase current reconstruction method, motor pre-drive chip and readable storage medium

Abstract

The present application provides a motor phase current reconstruction method, a motor pre-driver chip and a readable storage medium, and relates to the field of motor control technology. The present application sets up a dual-resistance sampling inverter bridge circuit between the motor pre-driver chip and the permanent magnet synchronous motor, so that the first operational amplifier unit in the motor pre-driver chip is reversely connected in parallel with the first sampling resistor in the dual-resistance sampling inverter bridge circuit, the second operational amplifier unit in the motor pre-driver chip is forwardly connected in parallel with the second sampling resistor in the dual-resistance sampling inverter bridge circuit, and the in-phase input terminal and the inverting input terminal of the third operational amplifier unit in the motor pre-driver chip are respectively connected to the non-grounded terminals of the first sampling resistor and the second sampling resistor, and then the three current sampling is realized by fully calling the three operational amplifier units provided as standard in the motor pre-driver chip, and the phase current sampling fluctuation is reduced by using the phase current sampling compensation method, so as to improve the accuracy of the dual-resistance current sampling and realize the high-precision motor three-phase current sampling function.

Description

Technical Field

[0001] The present application relates to the field of motor control technology, and in particular to a motor phase current reconstruction method, a motor pre-driver chip, and a readable storage medium. Background Art

[0002] With the rapid development of the modern electric power industry, permanent magnet synchronous motors (PMSM) are widely used in many electronic devices (for example, automotive brake systems, automotive steering systems, automotive suspension systems, etc.) due to their advantages such as simple structure, high operating reliability, no need for excitation current, and improved motor efficiency and power density. In the actual use of permanent magnet synchronous motors, field orientation control (FOC) technology is usually used for motor control, and accurate acquisition of the motor's three-phase current is a prerequisite for achieving high-quality field vector control effects. In order to save costs and circuit board space, a dual-resistance sampling scheme is usually used to restore the corresponding motor three-phase current.

[0003] At present, the existing dual resistor sampling solution (based on Figure 1 For example, a three-phase full-bridge inverter circuit is set up between the motor pre-drive chip and the permanent magnet synchronous motor, and any two single-phase full-bridge inverter circuits of the three-phase full-bridge inverter circuit (for example, Figure 1 The lower bridge arms of the U-phase full-bridge inverter circuit and the W-phase full-bridge inverter circuit in the three-phase full-bridge inverter circuit are connected in series with a sampling resistor, and then the six switching elements (for example, Figure 1 The on-off status of the switch elements Q1~Q6 in the full-bridge inverter circuit (wherein, the on-off status of the upper bridge switch element and the lower bridge switch element in the same phase full-bridge inverter circuit are always opposite) is adjusted, so that the motor pre-drive chip can be connected to the motor pre-drive chip at the zero vector moment of each motor control cycle (that is, the control moment when the three-phase upper bridge switch elements are all disconnected and the three-phase lower bridge switch elements are all turned on) through the operational amplifier unit (for example, Figure 1 The operational amplifier units AMP1 and AMP2 in the circuit, wherein the in-phase input terminal AMP1_P of the operational amplifier unit AMP1 is connected to the non-grounded terminal of the sampling resistor R1, the inverting input terminal AMP1_N of the operational amplifier unit AMP1 is connected to the grounded terminal of the sampling resistor R1, the in-phase input terminal AMP2_P of the operational amplifier unit AMP2 is connected to the non-grounded terminal of the sampling resistor R2, and the inverting input terminal AMP2_N of the operational amplifier unit AMP2 is connected to the grounded terminal of the sampling resistor R2) collects the voltage signal on the corresponding sampling resistor and combines it with the operational amplifier output reference voltage (i.e. Figure 1Vref in) into single-phase current (for example, Figure 1 The U-phase current and W-phase current of the permanent magnet synchronous motor in the middle), and then Kirchhoff's law reconstructs the last phase current at this zero vector moment (for example, Figure 1 V-phase current of the permanent magnet synchronous motor in the middle), thereby realizing the motor three-phase current sampling function.

[0004] However, it is worth noting that this dual-resistance sampling scheme will cause the motor pre-driver chip to have idle op amp units in the three op amp units that are standard for different shunt resistor sampling schemes (including three-resistance sampling schemes) (for example, Figure 1 The operational amplifier unit AMP3 in the motor pre-driver chip has a low utilization rate. At the same time, in the actual use of this dual-resistance sampling solution, two unused operational amplifier units (for example, Figure 1 The two-phase current directly sampled by the operational amplifier units AMP1 and AMP2 in the circuit board will often fluctuate due to fluctuations in sampling resistors, circuit board routing, operational amplifier unit differences, current sampling accuracy and other factors. This can easily lead to deviations in the two-phase current sampling results with the same amplitude in theory, making it impossible to achieve high-precision motor three-phase current sampling function, seriously affecting the subsequent motor control effect and easily causing serious motor control jitter. Summary of the invention

[0005] In view of this, the purpose of the present application is to provide a motor phase current reconstruction method, a motor pre-driver chip and a readable storage medium, which can fully call on the three operational amplifier units that come standard with the motor pre-driver chip to realize three-current sampling, and effectively reduce the phase current sampling fluctuations through phase current sampling compensation, and improve the accuracy of dual-resistance current sampling, so as to effectively improve the utilization rate of the motor pre-driver chip and realize high-precision motor three-phase current sampling function, so as to achieve smooth and accurate motor control effect.

[0006] In order to achieve the above purpose, the technical solution adopted in the embodiment of the present application is as follows:

[0007] In a first aspect, the present application provides a motor phase current reconstruction method, which is applied to a motor pre-driver chip, wherein the motor pre-driver chip is connected to a permanent magnet synchronous motor via a dual-resistance sampling inverter bridge circuit, wherein the dual-resistance sampling inverter bridge circuit includes a first sampling resistor and a second sampling resistor, and the motor pre-driver chip includes a first operational amplifier unit, a second operational amplifier unit, and a third operational amplifier unit, wherein the two input ends of the first operational amplifier unit are reversely connected in parallel with the two ends of the first sampling resistor, the two input ends of the second operational amplifier unit are forwardly connected in parallel with the two ends of the second sampling resistor, the in-phase input end of the third operational amplifier unit is connected to the non-grounded end of the first sampling resistor, and the inverting input end of the third operational amplifier unit is connected to the non-grounded end of the second sampling resistor; the motor phase current reconstruction method includes:

[0008] Detecting whether the dual-resistance sampling inverter bridge circuit meets the phase current compensation sampling condition at the current control moment;

[0009] When it is detected that the phase current compensation sampling condition is met, the actual vector current sampled by each of the three operational amplifier units at the current control moment is obtained;

[0010] Calculating a single-phase current compensation deviation of a single sampling resistor at the permanent magnet synchronous motor based on the three actual vector currents obtained;

[0011] According to the single-phase current compensation deviation and three actual vector currents, three-phase current compensation reconstruction is performed according to Kirchhoff's law to obtain the three-phase sampling current of the permanent magnet synchronous motor at the current control moment.

[0012] In an optional implementation, the step of detecting whether the dual-resistance sampling inverter bridge circuit meets the phase current compensation sampling condition at the current control moment includes:

[0013] Detecting whether the dual-resistance sampling inverter bridge circuit is in a three-phase upper bridge disconnected state at the current control moment, and detecting whether the dual-resistance sampling inverter bridge circuit is in a single-phase upper bridge conducted state at the previous control moment of the current control moment;

[0014] If it is detected that the dual-resistance sampling inverter bridge circuit is in a three-phase upper bridge disconnected state at the current control moment, and the dual-resistance sampling inverter bridge circuit is in a single-phase upper bridge turned on state at the previous control moment of the current control moment, then it is determined that the dual-resistance sampling inverter bridge circuit meets the phase current compensation sampling condition at the current control moment; otherwise, it is determined that the dual-resistance sampling inverter bridge circuit does not meet the phase current compensation sampling condition at the current control moment.

[0015] In an optional implementation manner, the step of calculating the single-phase current compensation deviation of a single sampling resistor at the permanent magnet synchronous motor based on the three actual vector currents obtained includes:

[0016] Performing a vector subtraction operation on the actual vector current of the second operational amplifier unit and the actual vector current of the first operational amplifier unit to obtain a reference vector current;

[0017] A vector current mean operation is performed on the reference vector current and the actual vector current of the third operational amplifier unit to obtain the single-phase current compensation deviation.

[0018] In an optional implementation, the step of performing three-phase current compensation reconstruction according to Kirchhoff's law based on the single-phase current compensation deviation and the three actual vector currents to obtain the three-phase sampling current of the permanent magnet synchronous motor at the current control moment includes:

[0019] For the first sampling resistor, current compensation is performed on the opposite vector current of the actual vector current of the first operational amplifier unit according to the single-phase current compensation deviation to obtain the first phase sampling current of the permanent magnet synchronous motor at the current control moment;

[0020] For the second sampling resistor, current compensation is performed on the actual vector current of the second operational amplifier unit according to the single-phase current compensation deviation to obtain the second-phase sampling current of the permanent magnet synchronous motor at the current control moment;

[0021] According to the first-phase sampling current and the second-phase sampling current, the third-phase sampling current of the permanent magnet synchronous motor at the current control moment is solved based on Kirchhoff's law, wherein the sum of the first-phase sampling current, the second-phase sampling current and the third-phase sampling current is zero.

[0022] In a second aspect, the present application provides a motor phase current reconstruction method, which is applied to a motor pre-driver chip, wherein the motor pre-driver chip is connected to a permanent magnet synchronous motor via a dual-resistance sampling inverter bridge circuit, wherein the dual-resistance sampling inverter bridge circuit includes a first sampling resistor and a second sampling resistor, and the motor pre-driver chip includes a first operational amplifier unit, a second operational amplifier unit, and a third operational amplifier unit, wherein the two input ends of the first operational amplifier unit are reversely connected in parallel with the two ends of the first sampling resistor, the two input ends of the second operational amplifier unit are forwardly connected in parallel with the two ends of the second sampling resistor, the in-phase input end of the third operational amplifier unit is connected to the non-grounded end of the first sampling resistor, and the inverting input end of the third operational amplifier unit is connected to the non-grounded end of the second sampling resistor; the motor phase current reconstruction method includes:

[0023] Detecting whether the dual-resistance sampling inverter bridge circuit meets the reference voltage compensation sampling condition at the current control moment;

[0024] When it is detected that the reference voltage compensation sampling condition is met, obtaining a reference voltage compensation deviation shared by the three operational amplifier units at the current control moment;

[0025] Performing voltage compensation on the operational amplifier output reference voltages used by the three operational amplifier units respectively according to the reference voltage compensation deviation, so as to obtain target vector currents sampled by the three operational amplifier units respectively based on the compensated operational amplifier output reference voltages at the current control moment;

[0026] According to the three target vector currents, three-phase current reconstruction is performed according to Kirchhoff's law to obtain the three-phase sampling current of the permanent magnet synchronous motor at the current control moment.

[0027] In an optional implementation, the step of detecting whether the dual-resistance sampling inverter bridge circuit meets the reference voltage compensation sampling condition at the current control moment includes:

[0028] Detecting whether the dual-resistance sampling inverter bridge circuit is in a single-phase lower bridge conduction state corresponding to the first sampling resistor or the second sampling resistor at a previous control moment before the current control moment, and detecting whether the dual-resistance sampling inverter bridge circuit is in a three-phase lower bridge conduction state at the current control moment;

[0029] If it is detected that the dual-resistance sampling inverter bridge circuit is in a single-phase lower bridge conduction state corresponding to the first sampling resistor or the second sampling resistor at the previous control moment, and the dual-resistance sampling inverter bridge circuit is in a three-phase lower bridge conduction state at the current control moment, then it is determined that the dual-resistance sampling inverter bridge circuit meets the reference voltage compensation sampling condition at the current control moment; otherwise, it is determined that the dual-resistance sampling inverter bridge circuit does not meet the reference voltage compensation sampling condition at the current control moment.

[0030] In an optional implementation manner, the step of obtaining the reference voltage compensation deviation shared by the three operational amplifier units at the current control moment includes:

[0031] When the dual-resistance sampling inverter bridge circuit is in a single-phase lower bridge conduction state corresponding to the first sampling resistor at the last control moment, a vector current mean operation is performed on the historical vector currents actually sampled by the first operational amplifier unit and the third operational amplifier unit at the last control moment to obtain the positive and negative current deviations of the first sampling resistor at the last control moment; or, when the dual-resistance sampling inverter bridge circuit is in a single-phase lower bridge conduction state corresponding to the second sampling resistor at the last control moment, a vector current mean operation is performed on the historical vector currents actually sampled by the second operational amplifier unit and the third operational amplifier unit at the last control moment to obtain the positive and negative current deviations of the second sampling resistor at the last control moment;

[0032] The forward and reverse current deviations, the actual resistance value of a single sampling resistor and the amplification factor of a single operational amplifier unit are multiplied to obtain a reference voltage compensation deviation at the current control moment.

[0033] In an optional implementation manner, the step of reconstructing the three-phase current according to Kirchhoff's law based on the three target vector currents to obtain the three-phase sampling current of the permanent magnet synchronous motor at the current control moment includes:

[0034] For the first sampling resistor, the opposite vector current of the target vector current of the first operational amplifier unit is directly used as the first phase sampling current of the permanent magnet synchronous motor at the current control moment;

[0035] For the second sampling resistor, directly using the target vector current of the second operational amplifier unit as the second phase sampling current of the permanent magnet synchronous motor at the current control moment;

[0036] According to the first-phase sampling current and the second-phase sampling current, the third-phase sampling current of the permanent magnet synchronous motor at the current control moment is solved based on Kirchhoff's law, wherein the sum of the first-phase sampling current, the second-phase sampling current and the third-phase sampling current is zero.

[0037] In a third aspect, the present application provides a motor pre-driver chip, which is connected to a permanent magnet synchronous motor via a resistance sampling inverter bridge circuit, wherein the dual-resistance sampling inverter bridge circuit includes a first sampling resistor and a second sampling resistor, and the motor pre-driver chip includes a first operational amplifier unit, a second operational amplifier unit, and a third operational amplifier unit, wherein two input ends of the first operational amplifier unit are reversely connected in parallel with two ends of the first sampling resistor, two input ends of the second operational amplifier unit are forwardly connected in parallel with two ends of the second sampling resistor, a non-inverting input end of the third operational amplifier unit is connected to a non-grounded end of the first sampling resistor, and an inverting input end of the third operational amplifier unit is connected to a non-grounded end of the second sampling resistor;

[0038] The motor pre-driver chip stores a computer program and can run the computer program to implement the motor phase current reconstruction method described in any one of the aforementioned implementations.

[0039] In a fourth aspect, the present application provides a readable storage medium having a computer program stored thereon. When the computer program is executed by a motor pre-driver chip, the motor phase current reconstruction method described in any one of the aforementioned embodiments is implemented, wherein the motor pre-driver chip is connected to the permanent magnet synchronous motor via a resistance sampling inverter bridge circuit, wherein the dual-resistance sampling inverter bridge circuit includes a first sampling resistor and a second sampling resistor, and the motor pre-driver chip includes a first operational amplifier unit, a second operational amplifier unit and a third operational amplifier unit, wherein the two input terminals of the first operational amplifier unit are reversely connected in parallel with the two terminals of the first sampling resistor, the two input terminals of the second operational amplifier unit are forward connected in parallel with the two terminals of the second sampling resistor, the in-phase input terminal of the third operational amplifier unit is connected to the non-grounded terminal of the first sampling resistor, and the inverting input terminal of the third operational amplifier unit is connected to the non-grounded terminal of the second sampling resistor.

[0040] In this case, the beneficial effects of the embodiments of the present application may include the following:

[0041] The present application sets up a dual-resistance sampling inverter bridge circuit between a motor pre-driver chip and a permanent magnet synchronous motor, so that the first operational amplifier unit in the motor pre-driver chip is reversely connected in parallel with the first sampling resistor in the dual-resistance sampling inverter bridge circuit, and the second operational amplifier unit in the motor pre-driver chip is forwardly connected in parallel with the second sampling resistor in the dual-resistance sampling inverter bridge circuit, and the in-phase input terminal and the inverting input terminal of the third operational amplifier unit in the motor pre-driver chip are respectively connected to the non-grounded terminals of the first sampling resistor and the second sampling resistor, and then at the control moment when the phase current compensation sampling condition is met, based on the actual vector current sampled by each of the three operational amplifier units, the single-phase current compensation deviation of the single sampling resistor at the permanent magnet synchronous motor is calculated to perform three-phase current compensation reconstruction, and the three-phase sampling of the permanent magnet synchronous motor is obtained. Current, or at the control moment when the reference voltage compensation sampling conditions are met, the reference voltage compensation deviation shared by the three operational amplifier units is used to compensate for the operational amplifier output reference voltage, and then the three-phase current is reconstructed based on the target vector current sampled by the three operational amplifier units under the compensated operational amplifier output reference voltage, so as to obtain the three-phase sampling current of the permanent magnet synchronous motor, so as to fully call the three operational amplifier units that come standard with the motor pre-driver chip to realize three-current sampling, and effectively reduce the phase current sampling fluctuation by means of phase current sampling compensation (including single-phase current deviation compensation and operational amplifier reference voltage compensation), and improve the accuracy of dual-resistance current sampling, so as to effectively improve the utilization rate of the motor pre-driver chip, and realize high-precision motor three-phase current sampling function, so as to achieve smooth and accurate motor control effect.

[0042] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, preferred embodiments are specifically cited below and described in detail with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0044] Figure 1 It is a circuit connection diagram of an existing dual-resistance sampling solution;

[0045] Figure 2 One of the circuit connection diagrams of the motor pre-drive chip, the dual-resistance sampling inverter bridge circuit and the permanent magnet synchronous motor provided in the embodiment of the present application;

[0046] Figure 3 The second circuit connection diagram of the motor pre-drive chip, the dual-resistance sampling inverter bridge circuit and the permanent magnet synchronous motor provided in the embodiment of the present application;

[0047] Figure 4 A schematic flow chart of a first motor phase current reconstruction method provided in an embodiment of the present application;

[0048] Figure 5 for Figure 2 or Figure 3 A schematic diagram of the three-phase current flow direction of the dual-resistance sampling inverter bridge circuit in the figure, which evolves from three single-phase upper bridge conduction states to three-phase upper bridge disconnection states;

[0049] Figure 6 A schematic flow chart of a second motor phase current reconstruction method provided in an embodiment of the present application;

[0050] Figure 7 for Figure 2 or Figure 3 A schematic diagram of the three-phase current flow direction of the dual-resistance sampling inverter bridge circuit in the single-phase lower bridge conduction state corresponding to the sampling resistor R1;

[0051] Figure 8 for Figure 2 or Figure 3 Schematic diagram of the three-phase current flow direction of the dual-resistance sampling inverter bridge circuit when the single-phase lower bridge corresponding to the sampling resistor R2 is in the on state.

[0052] Icon: 10-motor pre-drive chip; 20-dual-resistance sampling inverter bridge circuit; 30-permanent magnet synchronous motor; 11-first operational amplifier unit; 12-second operational amplifier unit; 13-third operational amplifier unit; 21-first sampling resistor; 22-second sampling resistor. DETAILED DESCRIPTION

[0053] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0054] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for which protection is sought, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0055] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0056] In the description of the present application, it should be understood that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships in which the product of the application is conventionally placed when in use, or are the orientations or positional relationships conventionally understood by those skilled in the art. They are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0057] In the description of this application, it should also be noted that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0058] In the description of the present application, it is to be understood that the relational terms such as the term "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. Moreover, the term "includes", "comprising" or any other variant thereof is intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or equipment. In the absence of more restrictions, the elements defined by the sentence "comprising one..." do not exclude the existence of other identical elements in the process, method, article or equipment including the elements. For those of ordinary skill in the art, the specific meaning of the above terms in the present application can be understood by specific circumstances.

[0059] In conjunction with the accompanying drawings, some embodiments of the present application are described in detail below. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0060] Please refer to Figure 2 and Figure 3 ,in Figure 2 This is one of the circuit connection diagrams of the motor pre-driver chip 10, the dual-resistance sampling inverter bridge circuit 20 and the permanent magnet synchronous motor 30 provided in the embodiment of the present application. Figure 3It is one of the circuit connection diagrams of the motor pre-driver chip 10, the dual-resistance sampling inverter bridge circuit 20 and the permanent magnet synchronous motor 30 provided in the embodiment of the present application. In the embodiment of the present application, the motor pre-driver chip 10 is connected to the permanent magnet synchronous motor 30 through the dual-resistance sampling inverter bridge circuit 20, so as to control the operation of the permanent magnet synchronous motor 30 by using the dual-resistance sampling inverter bridge circuit 20.

[0061] In this embodiment, the dual-resistance sampling inverter bridge circuit 20 includes a three-phase full-bridge inverter circuit, a first sampling resistor 21 and a second sampling resistor 22. The three-phase full-bridge inverter circuit is obtained by connecting three single-phase full-bridge inverter circuits in parallel. Each single-phase full-bridge inverter circuit is composed of an upper arm switch element (for example, Figure 2 or Figure 3 The switching element Q1, Q3 or Q5 in the bridge arm and a lower bridge arm switching element (for example, Figure 2 or Figure 3 The switching elements Q2, Q4 or Q6 in the single-phase full-bridge inverter circuit are connected in series, and the series connection point between the two switching elements corresponding to each single-phase full-bridge inverter circuit is connected to a single-phase coil interface of the permanent magnet synchronous motor 30 (for example, Figure 2 or Figure 3 In this case, each single-phase full-bridge inverter circuit corresponds to a single-phase coil interface (for example, Figure 2 or Figure 3 The U-phase full-bridge inverter circuit where the switching elements Q1 and Q2 are located, the V-phase full-bridge inverter circuit where the switching elements Q3 and Q4 are located, and the W-phase full-bridge inverter circuit where the switching elements Q5 and Q6 are located). Among them, the end of the upper bridge arm switching element in the three single-phase full-bridge inverter circuits that is away from the corresponding lower bridge arm switching element (i.e. Figure 2 or Figure 3 The drain terminals of the switching elements Q1, Q3 and Q5 in the circuit are connected to an external power source (eg, Figure 2 or Figure 3 The end of any two lower bridge arm switch elements in the three single-phase full-bridge inverter circuits away from the corresponding upper bridge arm switch elements is grounded via a sampling resistor (for example, Figure 2 or Figure 3 The lower arm switch element Q2 in the U-phase full-bridge inverter circuit is grounded via the sampling resistor R1, and the lower arm switch element Q6 in the W-phase full-bridge inverter circuit is grounded via the sampling resistor R2), and the end of the remaining lower arm switch element away from the corresponding upper arm switch element is directly grounded (i.e. Figure 2 or Figure 3 The actual resistance values ​​of the first sampling resistor 21 and the second sampling resistor 22 are consistent.

[0062] In this embodiment, the motor pre-driver chip 10 can be electrically connected to the six switch elements included in the dual-resistance sampling inverter bridge circuit 20, so as to achieve the SVPWM control effect of the permanent magnet synchronous motor 30 by regulating the on-off status of each of the six switch elements. Among them, the on-off status of the upper bridge arm switch element and the lower bridge arm switch element in the same phase full-bridge inverter circuit are always opposite.

[0063] In this embodiment, the motor pre-driver chip 10 may include a first operational amplifier unit 11, a second operational amplifier unit 12, and a third operational amplifier unit 13, wherein the two input terminals of the first operational amplifier unit 11 are connected in reverse parallel with the two ends of the first sampling resistor 21 (i.e., the in-phase input terminal of the first operational amplifier unit 11 is connected to the ground terminal of the first sampling resistor 21, and the inverting input terminal of the first operational amplifier unit 11 is connected to the non-ground terminal of the first sampling resistor 21), the two input terminals of the second operational amplifier unit 12 are connected in forward parallel with the two ends of the second sampling resistor 22 (i.e., the in-phase input terminal of the second operational amplifier unit 12 is connected to the non-ground terminal of the second sampling resistor 22, and the inverting input terminal of the second operational amplifier unit 12 is connected to the ground terminal of the second sampling resistor 22), the in-phase input terminal of the third operational amplifier unit 13 is connected to the non-ground terminal of the first sampling resistor 21, and the inverting input terminal of the third operational amplifier unit 13 is connected to the non-ground terminal of the second sampling resistor 22. Among them, the three operational amplifier units included in the motor pre-driver chip 10 share the same operational amplifier output reference voltage (such as Figure 2 or Figure 3 Vref in), the amplification factors of the three operational amplifier units are kept consistent; for any one of the three operational amplifier units, the vector current sampled at any time can be calculated using the formula "I=(VO-Vref) / (β×R0)", where "I" is used to represent the vector current sampled by the corresponding operational amplifier unit, "VO" is used to represent the sampled output voltage of the corresponding operational amplifier unit, "Vref" is used to represent the operational amplifier output reference voltage, "β" is used to represent the amplification factor of the corresponding operational amplifier unit, and "R0" is used to represent the actual resistance value of the first sampling resistor 21 or the second sampling resistor 22.

[0064] In this process, when the dual-resistance sampling inverter bridge circuit 20 is in the three-phase lower bridge conduction state (three-phase upper bridge disconnection state), for the first sampling resistor 21, the theoretical current equivalent relationship between the vector current sampled by the first operational amplifier unit 11 and the motor single-phase current corresponding to the first sampling resistor 21 is "the vector current sampled by the first operational amplifier unit 11 and the motor single-phase current corresponding to the first sampling resistor 21 are opposite in current direction"; and for the second sampling resistor 22, the vector current sampled by the second operational amplifier unit 12 is opposite to the motor single-phase current corresponding to the first sampling resistor 21. The theoretical current equivalent relationship between the single-phase current of the motor corresponding to the second sampling resistor 22 is "the vector current sampled by the first operational amplifier unit 11 is consistent with the single-phase current of the motor corresponding to the first sampling resistor 21"; the three-phase current of the motor at the permanent magnet synchronous motor 30 conforms to Kirchhoff's law "IU+IV+IW=0", where "IU" is used to represent the motor U-phase current of the permanent magnet synchronous motor 30, "IV" is used to represent the motor V-phase current of the permanent magnet synchronous motor 30, and "IW" is used to represent the motor W-phase current of the permanent magnet synchronous motor 30.

[0065] by Figure 2 For example, when selecting Figure 2 The sampling resistor R1 in the circuit is used as the first sampling resistor 21, and the sampling resistor R2 is selected as the first sampling resistor 21. Figure 2 When the sampling resistor R2 in the embodiment is used as the second sampling resistor 22, the first operational amplifier unit 11 is Figure 2 The operational amplifier unit AMP1 in the embodiment, the second operational amplifier unit 12 is Figure 2 The operational amplifier unit AMP2 in the embodiment, the third operational amplifier unit 13 is Figure 2The operational amplifier unit AMP3 in the circuit, at this time, the non-inverting input terminal AMP1_P of the operational amplifier unit AMP1 is connected to the ground terminal of the sampling resistor R1, the inverting input terminal AMP1_N of the operational amplifier unit AMP1 is connected to the non-ground terminal of the sampling resistor R1, the non-inverting input terminal AMP2_P of the operational amplifier unit AMP2 is connected to the non-ground terminal of the sampling resistor R2, the inverting input terminal AMP2_N of the operational amplifier unit AMP2 is connected to the ground terminal of the sampling resistor R2, the non-inverting input terminal AMP3_P of the operational amplifier unit AMP3 is connected to the non-ground terminal of the sampling resistor R1, and the inverting input terminal AMP3_N of the operational amplifier unit AMP3 is connected to the ground terminal of the sampling resistor R2. The input terminal AMP3_N is connected to the non-grounded terminal of the sampling resistor R2, wherein R1_P is used to represent the voltage signal of the sampling resistor R1 at the non-grounded terminal, R1_N is used to represent the voltage signal of the sampling resistor R1 at the grounded terminal, R2_P is used to represent the voltage signal of the sampling resistor R2 at the non-grounded terminal, R2_N is used to represent the voltage signal of the sampling resistor R2 at the grounded terminal, VO1 is used to represent the sampled output voltage of the operational amplifier unit AMP1, VO2 is used to represent the sampled output voltage of the operational amplifier unit AMP2, and VO3 is used to represent the sampled output voltage of the operational amplifier unit AMP3. At this time, if "I1" is used to represent the vector current sampled by the operational amplifier unit AMP1, "I2" is used to represent the vector current sampled by the operational amplifier unit AMP2, and "I3" is used to represent the vector current sampled by the operational amplifier unit AMP3, then Figure 2 The theoretical current equivalent relationship existing in the three-phase lower bridge conduction state can be expressed as "I1=-IU, I2=IW, I3=I1-I2=-IU-IW=IV".

[0066] by Figure 3 For example, when selecting Figure 3 The sampling resistor R2 in the circuit is used as the first sampling resistor 21, and the sampling resistor R2 in the circuit is selected as the first sampling resistor 21. Figure 3 When the sampling resistor R1 in the embodiment is used as the second sampling resistor 22, the first operational amplifier unit 11 is Figure 2 The operational amplifier unit AMP2 in the embodiment, the second operational amplifier unit 12 is Figure 2 The operational amplifier unit AMP1 in the embodiment of the present invention, the third operational amplifier unit 13 is Figure 2In the operational amplifier unit AMP3, at this time, the non-inverting input terminal AMP1_P of the operational amplifier unit AMP1 is connected to the non-grounded end of the sampling resistor R1, the inverting input terminal AMP1_N of the operational amplifier unit AMP1 is connected to the grounded end of the sampling resistor R1, the non-inverting input terminal AMP2_P of the operational amplifier unit AMP2 is connected to the grounded end of the sampling resistor R2, the inverting input terminal AMP2_N of the operational amplifier unit AMP2 is connected to the non-grounded end of the sampling resistor R2, the non-inverting input terminal AMP3_P of the operational amplifier unit AMP3 is connected to the non-grounded end of the sampling resistor R2, and the inverting input terminal AMP3_N of the operational amplifier unit AMP3 is connected to the non-grounded end of the sampling resistor R1, wherein R1_P is used to represent the voltage signal of the sampling resistor R1 at the non-grounded end, R1_N is used to represent the voltage signal of the sampling resistor R1 at the grounded end, R2_P is used to represent the voltage signal of the sampling resistor R2 at the non-grounded end, and R2_N is used to represent the voltage signal of the sampling resistor R2 at the grounded end. VO1 is used to represent the sampled output voltage of the operational amplifier unit AMP1, VO2 is used to represent the sampled output voltage of the operational amplifier unit AMP2, and VO3 is used to represent the sampled output voltage of the operational amplifier unit AMP3. At this time, if "I1" is used to represent the vector current sampled by the operational amplifier unit AMP1, "I2" is used to represent the vector current sampled by the operational amplifier unit AMP2, and "I3" is used to represent the vector current sampled by the operational amplifier unit AMP3, then Figure 3 The theoretical current equivalent relationship existing in the three-phase lower bridge conduction state can be expressed as "I1=IU, I2=-IW, I3=I2-I1=-IU-IW=IV".

[0067] In an embodiment of the present application, the motor pre-driver chip 10 may pre-store a specific computer program related to the motor phase current reconstruction function, and by running the stored specific computer program, fully call the three standard operational amplifier units to realize the three-current sampling function in the dual-resistance current sampling process, and effectively reduce the motor phase current sampling fluctuations through phase current sampling compensation (for example, single-phase current deviation compensation or operational amplifier reference voltage compensation), improve the accuracy of dual-resistance current sampling, so as to effectively improve the utilization rate of the motor pre-driver chip, and realize a high-precision motor three-phase current sampling function, so as to achieve a smooth and accurate motor control effect.

[0068] Understandably, Figure 2 or Figure 3 The block diagram shown is only a schematic diagram of any two circuit connections of the motor pre-driver chip 10, the dual-resistance sampling inverter bridge circuit 20 and the permanent magnet synchronous motor 30. The actual deployment method of the motor pre-driver chip 10, the dual-resistance sampling inverter bridge circuit 20 and the permanent magnet synchronous motor 30 is not limited to Figure 2 or Figure 3The circuit connection structure shown in FIG. 1 may also include a motor pre-driver chip 10. Figure 2 or Figure 3 More or fewer components than shown, or with Figure 2 or Figure 3 Different configurations are shown.

[0069] In the present application, in order to ensure that the motor pre-driver chip 10 can realize the three-phase current sampling function in the dual-resistance current sampling process, and use the single-phase current deviation compensation method to effectively reduce the motor phase current sampling fluctuation, improve the dual-resistance current sampling accuracy, thereby improving the utilization rate of the pre-driver chip while realizing the high-precision motor three-phase current sampling function, and facilitating the realization of a smooth and accurate motor control effect, the embodiment of the present application achieves the above-mentioned purpose by providing a motor phase current reconstruction method. The motor phase current reconstruction method provided by the present application is described in detail below.

[0070] Please refer to Figure 4 , Figure 4 is a flow chart of the first motor phase current reconstruction method provided in the embodiment of the present application. In the embodiment of the present application, Figure 4 The motor phase current reconstruction method shown may include steps S310 to S340.

[0071] Step S310, detecting whether the dual-resistance sampling inverter bridge circuit meets the phase current compensation sampling condition at the current control moment.

[0072] In this embodiment, the phase current compensation sampling condition is used to indicate that the motor pre-drive chip 10 performs motor three-phase current sampling only at the zero vector moment in a single motor control cycle, and needs to use the single-phase current deviation associated with the sampling resistor to compensate the single-phase current of the relevant motor to obtain a high-precision three-phase sampling current; wherein, for the phase current compensation sampling condition, the conventional SVPWM control scheme often causes the dual-resistance sampling inverter bridge circuit 20 to maintain any single-phase upper bridge conduction state as shown in 5 at the previous control moment of the zero vector moment in a single motor control cycle (for example, Figure 5 The U-phase upper bridge conduction state, the V-phase upper bridge conduction state or the W-phase upper bridge conduction state in the motor control cycle is maintained at the zero vector at all times. Figure 5 The three-phase upper bridge disconnected state shown in the figure can utilize the freewheeling characteristics of the inductor coil to adjust the motor single-phase current (for example, Figure 5The corresponding motor U phase current or motor W phase current) is approximately the same current. At this time, the phase current compensation sampling condition can be expressed as "the dual-resistance sampling inverter bridge circuit 20 is in a three-phase upper bridge disconnected state at the current control moment, and the dual-resistance sampling inverter bridge circuit 20 is in a single-phase upper bridge conductive state at the previous control moment of the current control moment".

[0073] In this process, please refer to Figure 5 , Figure 5 The red arrow in the figure is used to indicate the single-phase current flowing into the permanent magnet synchronous motor 30. Figure 5 The green arrow in is used to represent the motor single-phase current flowing out of the permanent magnet synchronous motor 30, Figure 5 The "on" in the formula is used to indicate that the corresponding switch element is in the on state. Figure 5 The "off" in the figure indicates that the corresponding switch element is in the off state; when the dual-resistance sampling inverter bridge circuit 20 evolves from a single-phase upper bridge conduction state to a three-phase upper bridge disconnection state at two adjacent control moments, the permanent magnet synchronous motor 30 will maintain the same motor three-phase current flow direction at these two control moments. At this time, the theoretical current equivalent relationship corresponding to the first sampling resistor 21 and the second sampling resistor 22 will be applicable to these two control moments at the same time, so as to accurately determine the single-phase current deviation associated with a single sampling resistor.

[0074] On this basis, the step S310 may include: detecting whether the dual-resistance sampling inverter bridge circuit 20 is in a three-phase upper bridge disconnected state at the current control moment, and detecting whether the dual-resistance sampling inverter bridge circuit 20 is in a single-phase upper bridge conducted state at the previous control moment of the current control moment; if it is detected that the dual-resistance sampling inverter bridge circuit 20 is in a three-phase upper bridge disconnected state at the current control moment, and the dual-resistance sampling inverter bridge circuit 20 is in a single-phase upper bridge conducted state at the previous control moment of the current control moment, then it is determined that the dual-resistance sampling inverter bridge circuit 20 meets the phase current compensation sampling condition at the current control moment, otherwise it is determined that the dual-resistance sampling inverter bridge circuit 20 does not meet the phase current compensation sampling condition at the current control moment.

[0075] Step S320, when it is detected that the phase current compensation sampling condition is met, the actual vector current sampled by each of the three operational amplifier units at the current control moment is obtained.

[0076] In this embodiment, when the motor pre-driver chip 10 determines that the phase current compensation sampling condition is met at the current control moment, it will use the formula "I=(VO-Vref) / (β×R0)" to drive the first operational amplifier unit 11, the second operational amplifier unit 12 and the third operational amplifier unit 13 to perform vector current sampling at the current control moment respectively, and obtain the actual vector current sampled by each of the three operational amplifier units at the current control moment.

[0077] Step S330: Calculate the single-phase current compensation deviation of a single sampling resistor at the permanent magnet synchronous motor based on the three actual vector currents obtained.

[0078] In this embodiment, after obtaining the actual vector current sampled by each of the three operational amplifier units at the current control moment, the motor pre-driver chip 10 will construct a single-phase current compensation deviation calculation formula "(the actual vector current of the second operational amplifier unit 12 - the actual vector current of the first operational amplifier unit 11 + the actual vector current of the third operational amplifier unit 13) / 2" associated with Kirchhoff's law that the permanent magnet synchronous motor 30 needs to satisfy based on the theoretical current equivalent relationship corresponding to each of the first sampling resistor 21 and the second sampling resistor 22 (for example, Figure 2 The corresponding single-phase current compensation deviation calculation formula is "(-I1+I2+I3) / 2", which is the same as Figure 3 The corresponding single-phase current compensation deviation calculation formula is “(-I2+I1+I3) / 2”, and then the single-phase current compensation deviation of the permanent magnet synchronous motor 30 at the current control moment is calculated based on the constructed single-phase current compensation deviation calculation formula.

[0079] At this time, the step S330 may include: performing a vector subtraction operation on the actual vector current of the second operational amplifier unit 12 and the actual vector current of the first operational amplifier unit 11 to obtain a reference vector current; performing a vector current mean operation on the reference vector current and the actual vector current of the third operational amplifier unit 13 to obtain a single-phase current compensation deviation of a single sampling resistor at the permanent magnet synchronous motor 30.

[0080] Step S340, performing three-phase current compensation reconstruction according to Kirchhoff's law based on the single-phase current compensation deviation and the three actual vector currents, to obtain the three-phase sampling current of the permanent magnet synchronous motor at the current control moment.

[0081] In this embodiment, after determining the single-phase current compensation deviation at the current control moment, the motor pre-driver chip 10 can solve the theoretical motor single-phase current corresponding to the two sampling resistors at the current control moment of the permanent magnet synchronous motor 30 based on the theoretical current equivalent relationship corresponding to the first sampling resistor 21 and the second sampling resistor 22, and then use the single-phase current compensation deviation to compensate the theoretical motor single-phase current corresponding to the two sampling resistors, and obtain the single-phase sampling current corresponding to the two sampling resistors and fitting the actual situation of the permanent magnet synchronous motor 30 at the current control moment, and then use Kirchhoff's law to solve the last phase sampling current of the permanent magnet synchronous motor 30 at the current control moment, so as to realize the high-precision motor three-phase current sampling function. Among them, for the first sampling resistor 21, the theoretical motor single-phase current corresponding to the first sampling resistor 21 is the opposite vector current of the actual vector current of the first operational amplifier unit 11; for the second sampling resistor 22, the theoretical motor single-phase current corresponding to the second sampling resistor 22 is the actual vector current of the second operational amplifier unit 12.

[0082] At this time, the step S340 may include:

[0083] For the first sampling resistor 21, current compensation is performed on the opposite vector current of the actual vector current of the first operational amplifier unit 11 according to the single-phase current compensation deviation to obtain the first phase sampling current of the permanent magnet synchronous motor 30 at the current control moment;

[0084] For the second sampling resistor 22, current compensation is performed on the actual vector current of the second operational amplifier unit 12 according to the single-phase current compensation deviation to obtain the second phase sampling current of the permanent magnet synchronous motor 30 at the current control moment;

[0085] According to the first-phase sampling current and the second-phase sampling current, the third-phase sampling current of the permanent magnet synchronous motor 30 at the current control moment is solved based on Kirchhoff's law, wherein the sum of the first-phase sampling current, the second-phase sampling current and the third-phase sampling current is zero.

[0086] In this process, the calculation formula of the first-phase sampling current can be expressed as "the first-phase sampling current = the single-phase current compensation deviation - the actual vector current of the first operational amplifier unit 11", the calculation formula of the second-phase sampling current can be expressed as "the second-phase sampling current = the single-phase current compensation deviation + the actual vector current of the second operational amplifier unit 12", and the calculation formula of the third-phase sampling current can be expressed as "the third-phase sampling current = the actual vector current of the first operational amplifier unit 11 - the actual vector current of the second operational amplifier unit 12 + 2×the single-phase current compensation deviation".

[0087] by Figure 2 For example, Figure 2 The U-phase sampling current can be calculated using the formula "IU=-I1+Ioffset", the W-phase sampling current can be calculated using the formula "IW=I2+Ioffset", and the V-phase sampling current can be calculated using the formula "IV=I1-I2-2×Ioffset", where "Ioffset" is used to represent the single-phase current compensation deviation.

[0088] And Figure 3 For example, Figure 3 The U-phase sampling current can be calculated using the formula "IU=I1+Ioffset", the W-phase sampling current can be calculated using the formula "IW=-I2+Ioffset", and the V-phase sampling current can be calculated using the formula "IV=I2-I1-2×Ioffset", where "Ioffset" is used to represent the single-phase current compensation deviation.

[0089] Therefore, the present application can fully call upon the three operational amplifier units provided as standard with the motor pre-driver chip 10 to realize the three-current sampling function in the dual-resistance current sampling process by executing the above steps S310 to S340, and utilize the single-phase current deviation compensation method to effectively reduce the motor phase current sampling fluctuation and improve the dual-resistance current sampling accuracy, thereby improving the utilization rate of the pre-driver chip while realizing a high-precision motor three-phase current sampling function, thereby achieving a smooth and accurate motor control effect.

[0090] In the present application, in order to ensure that the motor pre-driver chip 10 can realize the three-phase current sampling function in the dual-resistance current sampling process, and use the operational amplifier reference voltage compensation method to effectively reduce the motor phase current sampling fluctuation, improve the dual-resistance current sampling accuracy, thereby improving the utilization rate of the pre-driver chip while realizing the high-precision motor three-phase current sampling function, and facilitating the realization of a smooth and accurate motor control effect, the embodiment of the present application achieves the above-mentioned purpose by providing a motor phase current reconstruction method. The motor phase current reconstruction method provided by the present application is described in detail below.

[0091] Please refer to Figure 6 , Figure 6 is a flow chart of a second motor phase current reconstruction method provided in an embodiment of the present application. In an embodiment of the present application, Figure 6 The motor phase current reconstruction method shown may include steps S410 to S420.

[0092] Step S410, detecting whether the dual-resistance sampling inverter bridge circuit meets the reference voltage compensation sampling condition at the current control moment.

[0093] In this embodiment, the reference voltage compensation sampling condition is used to indicate that the motor pre-driver chip 10 needs to perform positive and negative current sampling for any sampling resistor at the last control moment of the zero vector moment in a single motor control cycle, so as to perform voltage compensation on the op amp output reference voltage used by the three op amp units based on the positive and negative current sampling results, and then perform motor three-phase current sampling at the zero vector moment to obtain a high-precision three-phase sampling current. Among them, for the reference voltage compensation sampling condition, it is necessary to adjust the conventional SVPWM control scheme by means of phase shifting, so that the double-resistance sampling inverter bridge circuit 20 maintains the single-phase lower bridge conduction state corresponding to the first sampling resistor 21 or the second sampling resistor 22 at the last control moment of the zero vector moment in a single motor control cycle (that is, only the lower bridge switch element directly connected to the first sampling resistor 21 or the second sampling resistor 22 in the three-phase lower bridge switch element is turned on), so as to use the three op amp units to realize the positive and negative current sampling function of the first sampling resistor 21 or the second sampling resistor 22 at the last control moment of the zero vector moment. At this time, the reference voltage compensation sampling condition can be expressed as "the dual-resistance sampling inverter bridge circuit 20 is in a three-phase lower bridge conduction state at the current control moment, and the dual-resistance sampling inverter bridge circuit 20 is in a single-phase lower bridge conduction state corresponding to the first sampling resistor 21 or the second sampling resistor 22 at the previous control moment of the current control moment".

[0094] In this process, when the dual-resistance sampling inverter bridge circuit 20 is in a single-phase lower bridge conduction state corresponding to the first sampling resistor 21, the lower bridge switch element directly connected to the second sampling resistor 22 is in a disconnected state. At this time, the non-ground terminal voltage of the second sampling resistor 22, the ground terminal voltage of the second sampling resistor 22 and the ground terminal voltage of the first sampling resistor 21 are the same. The input voltage of the third operational amplifier unit 13 is actually a voltage signal from the non-ground terminal to the ground terminal of the first sampling resistor 21, and the input voltage of the first operational amplifier unit 11 is a voltage signal from the ground terminal to the non-ground terminal of the first sampling resistor 21. The vector current sampled by the third operational amplifier unit 13 is actually a forward current on the first sampling resistor 21, and the vector current sampled by the first operational amplifier unit 11 is actually a reverse current on the first sampling resistor 21, that is, the theoretical vector current relationship between the third operational amplifier unit 13 and the first operational amplifier unit 11 in the single-phase lower bridge conduction state corresponding to the first sampling resistor 21 is "the current directions of the vector currents sampled by the first operational amplifier unit 11 and the third operational amplifier unit 13 are opposite".

[0095] When the dual-resistance sampling inverter bridge circuit 20 is in a single-phase lower bridge conduction state corresponding to the second sampling resistor 22, the lower bridge switch element directly connected to the first sampling resistor 21 is in a disconnected state. At this time, the non-ground terminal voltage of the first sampling resistor 21, the ground terminal voltage of the first sampling resistor 21 and the ground terminal voltage of the second sampling resistor 22 are the same. The input voltage of the third operational amplifier unit 13 is actually a voltage signal from the ground terminal to the non-ground terminal of the second sampling resistor 22, and the input voltage of the second operational amplifier unit 12 is a voltage signal from the non-ground terminal to the ground terminal of the second sampling resistor 22. The vector current sampled by the third operational amplifier unit 13 is actually a reverse current on the second sampling resistor 22, and the vector current sampled by the second operational amplifier unit 12 is actually a forward current on the second sampling resistor 22, that is, the theoretical vector current relationship between the third operational amplifier unit 13 and the second operational amplifier unit 12 in the single-phase lower bridge conduction state corresponding to the second sampling resistor 22 is "the current directions of the vector currents sampled by the second operational amplifier unit 12 and the third operational amplifier unit 13 are opposite".

[0096] by Figure 2 , Figure 7 and Figure 8 For example, Figure 7 and Figure 8 The red arrows in the figure are used to indicate the single-phase current flowing into the permanent magnet synchronous motor 30. Figure 7 and Figure 8 The green arrows in FIG. 1 are used to indicate the single-phase current of the motor flowing out of the permanent magnet synchronous motor 30. Figure 7 and Figure 8 The "on" in the formula is used to indicate that the corresponding switch element is in the on state. Figure 7 and Figure 8 The "off" in the word "off" indicates that the corresponding switch element is in the off state. Figure 2 The sampling resistor R1 in the circuit is used as the first sampling resistor 21, and the sampling resistor R2 is selected as the first sampling resistor 21. Figure 2 When the sampling resistor R2 in the embodiment is used as the second sampling resistor 22, the first operational amplifier unit 11 is Figure 2 The operational amplifier unit AMP1 in the embodiment, the second operational amplifier unit 12 is Figure 2 The operational amplifier unit AMP2 in the embodiment, the third operational amplifier unit 13 is Figure 2 In the operational amplifier unit AMP3, if the dual-resistance sampling inverter bridge circuit 20 is in the U-phase lower bridge conduction state corresponding to the sampling resistor R1, the corresponding theoretical vector current relationship is "I3=-I1", and if the dual-resistance sampling inverter bridge circuit 20 is in the W-phase lower bridge conduction state corresponding to the sampling resistor R2, the corresponding theoretical vector current relationship is "I3=-I2".

[0097] by Figure 3 , Figure 7 and Figure 8 For example, Figure 7 and Figure 8 The red arrows in the figure are used to indicate the single-phase current flowing into the permanent magnet synchronous motor 30. Figure 7 and Figure 8 The green arrows in FIG. 1 are used to indicate the single-phase current of the motor flowing out of the permanent magnet synchronous motor 30. Figure 7 and Figure 8 The "on" in the formula is used to indicate that the corresponding switch element is in the on state. Figure 7 and Figure 8 The "off" in the word "off" indicates that the corresponding switch element is in the off state. Figure 3 The sampling resistor R2 in the circuit is used as the first sampling resistor 21, and the sampling resistor R2 in the circuit is selected as the first sampling resistor 21. Figure 3 When the sampling resistor R1 in the embodiment is used as the second sampling resistor 22, the first operational amplifier unit 11 is Figure 3 The operational amplifier unit AMP2 in the embodiment, the second operational amplifier unit 12 is Figure 3 The operational amplifier unit AMP1 in the embodiment of the present invention, the third operational amplifier unit 13 is Figure 2 In the operational amplifier unit AMP3, if the dual-resistance sampling inverter bridge circuit 20 is in the U-phase lower bridge conduction state corresponding to the sampling resistor R1, the corresponding theoretical vector current relationship is "I3=-I1", and if the dual-resistance sampling inverter bridge circuit 20 is in the W-phase lower bridge conduction state corresponding to the sampling resistor R2, the corresponding theoretical vector current relationship is "I3=-I2".

[0098] On this basis, the step S410 may include: detecting whether the dual-resistance sampling inverter bridge circuit 20 is in a single-phase lower bridge conduction state corresponding to the first sampling resistor 21 or the second sampling resistor 22 at the previous control moment of the current control moment, and detecting whether the dual-resistance sampling inverter bridge circuit 20 is in a three-phase lower bridge conduction state at the current control moment; if it is detected that the dual-resistance sampling inverter bridge circuit 20 is in a single-phase lower bridge conduction state corresponding to the first sampling resistor 21 or the second sampling resistor 22 at the previous control moment, and the dual-resistance sampling inverter bridge circuit 20 is in a three-phase lower bridge conduction state at the current control moment, then it is determined that the dual-resistance sampling inverter bridge circuit 20 meets the reference voltage compensation sampling condition at the current control moment, otherwise it is determined that the dual-resistance sampling inverter bridge circuit 20 does not meet the reference voltage compensation sampling condition at the current control moment.

[0099] Step S420, when it is detected that the reference voltage compensation sampling condition is met, obtaining the reference voltage compensation deviation shared by the three operational amplifier units at the current control moment.

[0100] In this embodiment, when the motor pre-driver chip 10 determines that the current control moment meets the reference voltage compensation sampling condition, it will calculate the positive and negative current deviations at the previous control moment based on the positive and negative current sampling results of the three operational amplifier units at the previous control moment of the current control moment, and then calculate the reference voltage compensation deviation that matches the positive and negative current deviations based on the operational amplifier principle.

[0101] At this time, the step S420 may include:

[0102] When the dual-resistance sampling inverter bridge circuit 20 is in the single-phase lower bridge conduction state corresponding to the first sampling resistor 21 at the last control moment, the vector current mean operation is performed on the historical vector current actually sampled by the first operational amplifier unit 11 and the third operational amplifier unit 13 at the last control moment, so as to obtain the positive and negative current deviation of the first sampling resistor 21 at the last control moment; or, when the dual-resistance sampling inverter bridge circuit 20 is in the single-phase lower bridge conduction state corresponding to the second sampling resistor 22 at the last control moment, the vector current mean operation is performed on the historical vector current actually sampled by the second operational amplifier unit 12 and the third operational amplifier unit 13 at the last control moment, so as to obtain the positive and negative current deviation of the second sampling resistor 22 at the last control moment;

[0103] The forward and reverse current deviations, the actual resistance value of a single sampling resistor and the amplification factor of a single operational amplifier unit are multiplied to obtain a reference voltage compensation deviation at the current control moment.

[0104] Step S430 , performing voltage compensation on the operational amplifier output reference voltages used by the three operational amplifier units respectively according to the reference voltage compensation deviation, and obtaining target vector currents sampled by the three operational amplifier units respectively based on the compensated operational amplifier output reference voltages at the current control moment.

[0105] In this embodiment, the op amp output reference voltage of each op amp unit after compensation at the current control moment is obtained by adding the op amp output reference voltage commonly used by the three op amp units at the previous control moment of the current control moment and the reference voltage compensation deviation at the current control moment; when determining the op amp output reference voltage of the three op amp units after compensation at the current control moment, the motor pre-driver chip 10 will use the formula "I=(VO-Vref) / (β×R0)" to drive the first op amp unit 11, the second op amp unit 12 and the third op amp unit 13 to perform vector current sampling at the current control moment respectively, and obtain the target vector current sampled by each of the three op amp units at the current control moment.

[0106] Step S440 , performing three-phase current reconstruction according to the three target vector currents and Kirchhoff's law to obtain the three-phase sampling current of the permanent magnet synchronous motor at the current control moment.

[0107] In this embodiment, after determining the three target vector currents at the current control moment, the motor pre-driver chip 10 can solve the single-phase sampling currents of the permanent magnet synchronous motor 30 corresponding to the two sampling resistors and fitting the actual situation at the current control moment based on the theoretical current equivalent relationship corresponding to each of the first sampling resistor 21 and the second sampling resistor 22, and then use Kirchhoff's law to solve the last phase sampling current of the permanent magnet synchronous motor 30 at the current control moment, so as to realize the high-precision motor three-phase current sampling function. Among them, for the first sampling resistor 21, the single-phase sampling current corresponding to the first sampling resistor 21 is the opposite vector current of the target vector current of the first operational amplifier unit 11; for the second sampling resistor 22, the single-phase sampling current corresponding to the second sampling resistor 22 is the target vector current of the second operational amplifier unit 12.

[0108] At this time, the step S440 may include:

[0109] With respect to the first sampling resistor 21, the opposite vector current of the target vector current of the first operational amplifier unit 11 is directly used as the first phase sampling current of the permanent magnet synchronous motor 30 at the current control moment;

[0110] With respect to the second sampling resistor 22 , the target vector current of the second operational amplifier unit 12 is directly used as the second phase sampling current of the permanent magnet synchronous motor 30 at the current control moment;

[0111] According to the first-phase sampling current and the second-phase sampling current, the third-phase sampling current of the permanent magnet synchronous motor 30 at the current control moment is solved based on Kirchhoff's law, wherein the sum of the first-phase sampling current, the second-phase sampling current and the third-phase sampling current is zero.

[0112] In this process, the calculation formula of the first-phase sampling current can be expressed as "the first-phase sampling current=-the target vector current of the first operational amplifier unit 11", the calculation formula of the second-phase sampling current can be expressed as "the second-phase sampling current=the target vector current of the second operational amplifier unit 12", and the calculation formula of the third-phase sampling current can be expressed as "the third-phase sampling current=the target vector current of the first operational amplifier unit 11-the target vector current of the second operational amplifier unit 12".

[0113] Therefore, the present application can fully call upon the three operational amplifier units provided as standard with the motor pre-driver chip 10 to realize the three-current sampling function in the dual-resistance current sampling process by executing the above steps S410 to S440, and utilize the operational amplifier reference voltage compensation method to effectively reduce the motor phase current sampling fluctuation and improve the dual-resistance current sampling accuracy, thereby improving the utilization rate of the pre-driver chip while realizing a high-precision motor three-phase current sampling function, thereby achieving a smooth and accurate motor control effect.

[0114] In addition, in the present application, an embodiment of the present application further provides a readable storage medium, wherein the readable storage medium stores a computer program, and the computer program can be executed by the motor pre-driver chip 10 to implement Figure 4 or Figure 6 The motor phase current reconstruction method shown ensures that the three operational amplifier units of the motor pre-driver chip 10 can be fully called to realize the three-current sampling function in the dual-resistance current sampling process, and can effectively reduce the phase current sampling fluctuation by means of phase current sampling compensation (including single-phase current deviation compensation and operational amplifier reference voltage compensation), improve the accuracy of dual-resistance current sampling, improve the utilization rate of the pre-driver chip, and realize the high-precision motor three-phase current sampling function, so as to achieve a smooth and accurate motor control effect. Among them, the readable storage medium can include but is not limited to: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or CD and other media that can store program codes.

[0115] The above are only various implementations of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A motor phase current reconstruction method, characterized in that: Applied to a motor pre-driver chip, the motor pre-driver chip is connected to a permanent magnet synchronous motor via a dual-resistance sampling inverter bridge circuit, wherein the dual-resistance sampling inverter bridge circuit includes a first sampling resistor and a second sampling resistor, the motor pre-driver chip includes a first operational amplifier unit, a second operational amplifier unit and a third operational amplifier unit, the two input ends of the first operational amplifier unit are reversely connected in parallel with the two ends of the first sampling resistor, the two input ends of the second operational amplifier unit are forwardly connected in parallel with the two ends of the second sampling resistor, the in-phase input end of the third operational amplifier unit is connected to the non-grounded end of the first sampling resistor, and the inverting input end of the third operational amplifier unit is connected to the non-grounded end of the second sampling resistor; The motor phase current reconstruction method comprises: Detecting whether the dual-resistance sampling inverter bridge circuit meets a phase current compensation sampling condition at the current control moment, wherein the phase current compensation sampling condition is that the dual-resistance sampling inverter bridge circuit is in a three-phase upper bridge disconnected state at the current control moment and is in a single-phase upper bridge conductive state at a control moment before the current control moment; When it is detected that the phase current compensation sampling condition is met, the actual vector current sampled by each of the three operational amplifier units at the current control moment is obtained; Calculating a single-phase current compensation deviation of a single sampling resistor at the permanent magnet synchronous motor based on the three actual vector currents obtained; According to the single-phase current compensation deviation and three actual vector currents, three-phase current compensation reconstruction is performed according to Kirchhoff's law to obtain the three-phase sampling current of the permanent magnet synchronous motor at the current control moment.

2. The motor phase current reconstruction method according to claim 1, characterized in that: The step of detecting whether the dual-resistance sampling inverter bridge circuit meets the phase current compensation sampling condition at the current control moment includes: Detecting whether the dual-resistance sampling inverter bridge circuit is in a three-phase upper bridge disconnected state at the current control moment, and detecting whether the dual-resistance sampling inverter bridge circuit is in a single-phase upper bridge conducted state at the previous control moment of the current control moment; If it is detected that the dual-resistance sampling inverter bridge circuit is in a three-phase upper bridge disconnected state at the current control moment, and the dual-resistance sampling inverter bridge circuit is in a single-phase upper bridge turned on state at the previous control moment of the current control moment, then it is determined that the dual-resistance sampling inverter bridge circuit meets the phase current compensation sampling condition at the current control moment; otherwise, it is determined that the dual-resistance sampling inverter bridge circuit does not meet the phase current compensation sampling condition at the current control moment.

3. The motor phase current reconstruction method according to claim 1, characterized in that: The step of calculating the single-phase current compensation deviation of a single sampling resistor at the permanent magnet synchronous motor based on the three actual vector currents obtained includes: Performing a vector subtraction operation on the actual vector current of the second operational amplifier unit and the actual vector current of the first operational amplifier unit to obtain a reference vector current; A vector current mean operation is performed on the reference vector current and the actual vector current of the third operational amplifier unit to obtain the single-phase current compensation deviation.

4. The motor phase current reconstruction method according to any one of claims 1 to 3, characterized in that: The step of performing three-phase current compensation reconstruction according to Kirchhoff's law based on the single-phase current compensation deviation and the three actual vector currents to obtain the three-phase sampling current of the permanent magnet synchronous motor at the current control moment includes: For the first sampling resistor, current compensation is performed on the opposite vector current of the actual vector current of the first operational amplifier unit according to the single-phase current compensation deviation to obtain the first phase sampling current of the permanent magnet synchronous motor at the current control moment; For the second sampling resistor, current compensation is performed on the actual vector current of the second operational amplifier unit according to the single-phase current compensation deviation to obtain the second-phase sampling current of the permanent magnet synchronous motor at the current control moment; According to the first-phase sampling current and the second-phase sampling current, the third-phase sampling current of the permanent magnet synchronous motor at the current control moment is solved based on Kirchhoff's law, wherein the sum of the first-phase sampling current, the second-phase sampling current and the third-phase sampling current is zero.

5. A motor phase current reconstruction method, characterized in that: Applied to a motor pre-driver chip, the motor pre-driver chip is connected to a permanent magnet synchronous motor via a dual-resistance sampling inverter bridge circuit, wherein the dual-resistance sampling inverter bridge circuit includes a first sampling resistor and a second sampling resistor, the motor pre-driver chip includes a first operational amplifier unit, a second operational amplifier unit and a third operational amplifier unit, the two input ends of the first operational amplifier unit are reversely connected in parallel with the two ends of the first sampling resistor, the two input ends of the second operational amplifier unit are forwardly connected in parallel with the two ends of the second sampling resistor, the in-phase input end of the third operational amplifier unit is connected to the non-grounded end of the first sampling resistor, and the inverting input end of the third operational amplifier unit is connected to the non-grounded end of the second sampling resistor; The motor phase current reconstruction method comprises: Detecting whether the dual-resistance sampling inverter bridge circuit meets a reference voltage compensation sampling condition at a current control moment, wherein the reference voltage compensation sampling condition is that the dual-resistance sampling inverter bridge circuit is in a three-phase lower bridge conduction state at the current control moment and is in a single-phase lower bridge conduction state corresponding to the first sampling resistor or the second sampling resistor at a control moment before the current control moment; When it is detected that the reference voltage compensation sampling condition is met, obtaining a reference voltage compensation deviation shared by the three operational amplifier units at the current control moment; Performing voltage compensation on the operational amplifier output reference voltages used by the three operational amplifier units respectively according to the reference voltage compensation deviation, so as to obtain target vector currents sampled by the three operational amplifier units respectively based on the compensated operational amplifier output reference voltages at the current control moment; According to the three target vector currents, three-phase current reconstruction is performed according to Kirchhoff's law to obtain the three-phase sampling current of the permanent magnet synchronous motor at the current control moment.

6. The motor phase current reconstruction method according to claim 5, characterized in that: The step of detecting whether the dual-resistance sampling inverter bridge circuit meets the reference voltage compensation sampling condition at the current control moment includes: Detecting whether the dual-resistance sampling inverter bridge circuit is in a single-phase lower bridge conduction state corresponding to the first sampling resistor or the second sampling resistor at a previous control moment before the current control moment, and detecting whether the dual-resistance sampling inverter bridge circuit is in a three-phase lower bridge conduction state at the current control moment; If it is detected that the dual-resistance sampling inverter bridge circuit is in a single-phase lower bridge conduction state corresponding to the first sampling resistor or the second sampling resistor at the previous control moment, and the dual-resistance sampling inverter bridge circuit is in a three-phase lower bridge conduction state at the current control moment, then it is determined that the dual-resistance sampling inverter bridge circuit meets the reference voltage compensation sampling condition at the current control moment; otherwise, it is determined that the dual-resistance sampling inverter bridge circuit does not meet the reference voltage compensation sampling condition at the current control moment.

7. The motor phase current reconstruction method according to claim 6, characterized in that: The step of obtaining the reference voltage compensation deviation shared by the three operational amplifier units at the current control moment includes: When the dual-resistance sampling inverter bridge circuit is in a single-phase lower bridge conduction state corresponding to the first sampling resistor at the last control moment, a vector current mean operation is performed on the historical vector currents actually sampled by the first operational amplifier unit and the third operational amplifier unit at the last control moment to obtain the positive and negative current deviations of the first sampling resistor at the last control moment; or, when the dual-resistance sampling inverter bridge circuit is in a single-phase lower bridge conduction state corresponding to the second sampling resistor at the last control moment, a vector current mean operation is performed on the historical vector currents actually sampled by the second operational amplifier unit and the third operational amplifier unit at the last control moment to obtain the positive and negative current deviations of the second sampling resistor at the last control moment; The forward and reverse current deviations, the actual resistance value of a single sampling resistor and the amplification factor of a single operational amplifier unit are multiplied to obtain a reference voltage compensation deviation at the current control moment.

8. The motor phase current reconstruction method according to any one of claims 5 to 7, characterized in that: The step of reconstructing the three-phase current according to Kirchhoff's law based on the three target vector currents to obtain the three-phase sampling current of the permanent magnet synchronous motor at the current control moment includes: For the first sampling resistor, the opposite vector current of the target vector current of the first operational amplifier unit is directly used as the first phase sampling current of the permanent magnet synchronous motor at the current control moment; For the second sampling resistor, directly using the target vector current of the second operational amplifier unit as the second phase sampling current of the permanent magnet synchronous motor at the current control moment; According to the first-phase sampling current and the second-phase sampling current, the third-phase sampling current of the permanent magnet synchronous motor at the current control moment is solved based on Kirchhoff's law, wherein the sum of the first-phase sampling current, the second-phase sampling current and the third-phase sampling current is zero.

9. A motor pre-driver chip, characterized in that: The motor pre-driver chip is connected to the permanent magnet synchronous motor via a resistance sampling inverter bridge circuit, wherein the dual resistance sampling inverter bridge circuit includes a first sampling resistor and a second sampling resistor, and the motor pre-driver chip includes a first operational amplifier unit, a second operational amplifier unit and a third operational amplifier unit, wherein two input ends of the first operational amplifier unit are reversely connected in parallel with two ends of the first sampling resistor, two input ends of the second operational amplifier unit are forwardly connected in parallel with two ends of the second sampling resistor, a non-inverting input end of the third operational amplifier unit is connected to a non-grounded end of the first sampling resistor, and an inverting input end of the third operational amplifier unit is connected to a non-grounded end of the second sampling resistor; The motor pre-driver chip stores a computer program and can run the computer program to implement the motor phase current reconstruction method described in any one of claims 1-8.

10. A readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by the motor pre-driver chip, the motor phase current reconstruction method described in any one of claims 1 to 8 is implemented, wherein the motor pre-driver chip is connected to the permanent magnet synchronous motor via a resistance sampling inverter bridge circuit, wherein the dual-resistance sampling inverter bridge circuit includes a first sampling resistor and a second sampling resistor, and the motor pre-driver chip includes a first operational amplifier unit, a second operational amplifier unit and a third operational amplifier unit, wherein the two input ends of the first operational amplifier unit are reversely connected in parallel with the two ends of the first sampling resistor, the two input ends of the second operational amplifier unit are forwardly connected in parallel with the two ends of the second sampling resistor, the in-phase input end of the third operational amplifier unit is connected to the non-grounded end of the first sampling resistor, and the inverting input end of the third operational amplifier unit is connected to the non-grounded end of the second sampling resistor.

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