Motor phase current sampling device and method, chip and motor controller

Abstract

The invention discloses a motor phase current sampling device and method, a chip and a motor controller, the device comprises a reference voltage providing unit, a sampling unit and a control unit, the reference voltage providing unit is connected with the reference ground end of the sampling unit, and the control unit is connected with the sampling unit; the reference voltage providing unit is used for outputting partial voltage of neutral point voltage of the motor; the sampling unit is used for sampling a motor phase voltage corresponding to each phase of bridge arm in the multi-phase bridge arm based on voltage division; the control unit is used for controlling the reference voltage providing unit to output the partial voltage of the voltage of the neutral point of the corresponding motor in the target sampling period of each phase of bridge arm in a pulse modulation period, and controlling the sampling unit to sample the corresponding motor phase voltage based on the partial voltage to obtain a plurality of motor phase voltage sampling values. Determining a motor phase current according to the plurality of motor phase voltage sampling values; wherein the target sampling time period is the time period from the dead time corresponding to each phase of bridge arm to the time period before follow current is completed. The phase current sampling cost of the device is low.

Description

Technical Field

[0001] The present invention relates to the field of motor control, and in particular to a motor phase current sampling device and method, a chip, and a motor controller. Background Art

[0002] In the field of motor control, motor phase current has always been one of the important control parameters. During the operation of the motor, by monitoring the phase current signal of the motor, the load condition, speed, power, efficiency and other parameters of the motor can be understood, thereby realizing the control and protection of the motor. At present, the relevant technology usually adopts the single resistor sampling method to obtain the motor phase current. This method does not require the use of relatively expensive current sensors and has low hardware costs, so it is widely used. However, due to the complexity of the algorithm of the single resistor sampling method and the need to perform phase shifting and sampling point calculations during the sampling process of the phase current, this not only consumes a lot of computing resources, but also generates large harmonic noise and interferes with motor control, resulting in the high sampling cost of the motor phase current. Summary of the Invention

[0003] The present invention aims to solve at least one of the technical problems in the related art to a certain extent. To this end, the first object of the present invention is to provide a motor phase current sampling device, which is provided with a reference voltage providing unit, a sampling unit and a control unit in the device, wherein the reference voltage providing unit is connected to the reference ground terminal of the sampling unit, and the control unit is connected to the sampling unit. The control unit can control the reference voltage providing unit to output the corresponding motor neutral point voltage divided voltage within the target sampling period of each phase bridge arm in a pulse modulation cycle, and control the sampling unit to sample the corresponding motor phase voltage based on the divided voltage to obtain multiple motor phase voltage sampling values, and determine the motor phase current based on the multiple motor phase voltage sampling values, thereby realizing the sampling function of the motor phase current without the need for phase shifting and sampling point calculation, avoiding the problem of possible harmonic generation that interferes with the operation of the motor, and the algorithm is simple and consumes less computing resources, thereby effectively reducing the phase current sampling cost of the motor.

[0004] A second objective of the present invention is to provide a motor controller.

[0005] The third object of the present invention is to provide a chip.

[0006] A fourth object of the present invention is to provide an electrical device.

[0007] A fifth object of the present invention is to provide a motor phase current sampling method.

[0008] To achieve the above-mentioned purpose, an embodiment of the first aspect of the present invention proposes a motor phase current sampling device, which is applied to a motor controller, and the motor controller includes a multi-phase bridge arm. The device includes: a reference voltage providing unit, a sampling unit and a control unit, the reference voltage providing unit is connected to the reference ground terminal of the sampling unit, and the control unit is connected to the sampling unit; the reference voltage providing unit is used to output the divided voltage of the motor neutral point voltage; the sampling unit is used to sample the motor phase voltage corresponding to each phase bridge arm in the multi-phase bridge arm based on the divided voltage; the control unit is used to control the reference voltage providing unit to output the divided voltage of the corresponding motor neutral point voltage within the target sampling period of each phase bridge arm in a pulse modulation cycle, and control the sampling unit to sample the corresponding motor phase voltage based on the divided voltage, to obtain multiple motor phase voltage sampling values, and to determine the motor phase current based on the multiple motor phase voltage sampling values; wherein the target sampling period is the period from the start of the dead time corresponding to each phase bridge arm to the completion of the freewheeling.

[0009] According to an embodiment of the present invention, a motor phase current sampling device is provided with a reference voltage providing unit, a sampling unit and a control unit in the device, wherein the reference voltage providing unit is connected to the reference ground terminal of the sampling unit, and the control unit is connected to the sampling unit. The control unit can control the reference voltage providing unit to output the corresponding motor neutral point voltage divided voltage within the target sampling period of each phase bridge arm in a pulse modulation cycle, and control the sampling unit to sample the corresponding motor phase voltage based on the divided voltage to obtain multiple motor phase voltage sampling values, and determine the motor phase current based on the multiple motor phase voltage sampling values, thereby realizing the sampling function of the motor phase current without the need for phase shifting and sampling point calculation, avoiding the problem of possible generation of harmonics that interfere with the operation of the motor, and the algorithm is simple and consumes less computing resources, thereby effectively reducing the phase current sampling cost of the motor.

[0010] According to one embodiment of the present invention, the reference voltage providing unit includes: a digital-to-analog conversion unit, which is respectively connected to the reference ground terminal of the sampling unit and the control unit, wherein the control unit is used to output a divided digital signal to the digital-to-analog conversion unit so that the digital-to-analog conversion unit converts the digital signal and outputs the divided voltage.

[0011] According to one embodiment of the present invention, the reference voltage providing unit includes: a voltage divider circuit and a controllable switch, the controllable switch is respectively connected to the voltage divider circuit, the reference ground terminal of the sampling unit and the control unit, wherein the control unit is used to control the controllable switch so that the voltage divider circuit outputs a divided voltage.

[0012] According to one embodiment of the present invention, the control unit is further configured to determine the divided voltage of the neutral point voltage of the motor within the target sampling period based on the duty cycle of the multi-phase bridge arms during the pulse modulation period.

[0013] According to one embodiment of the present invention, the multi-phase bridge arm includes a three-phase bridge arm, and the duty cycle includes a minimum duty cycle, an intermediate duty cycle and a maximum duty cycle, wherein the control unit is specifically used to: determine that the voltage division of the motor neutral point voltage within the target sampling period of the bridge arm corresponding to the minimum duty cycle is the voltage division of the DC bus voltage of the motor controller; determine that the voltage division of the motor neutral point voltage within the target sampling period of the bridge arm corresponding to the intermediate duty cycle is one half of the voltage division of the DC bus voltage; determine that the voltage division of the motor neutral point voltage within the target sampling period of the bridge arm corresponding to the maximum duty cycle is zero.

[0014] According to one embodiment of the present invention, the power frequency cycle of the motor is divided into multiple current intervals, and the control unit is used to determine the target current interval based on multiple motor phase voltage sampling values, and calculate the positive values ​​of the multiple motor phase voltage sampling values ​​and the motor winding resistance to obtain at least one first motor phase current, and reconstruct at least one second motor phase current based on the at least one first motor phase current and the target current interval.

[0015] According to one embodiment of the present invention, the multi-phase bridge arm is a three-phase bridge arm, and the control unit is specifically used to: when the first motor phase current includes multiple and the second motor phase current includes one, calculate the second motor phase current based on the multiple first motor phase currents; when the first motor phase current includes one and the second motor phase current includes multiple, obtain at least one second motor phase current from the previous current interval according to the target current interval, and calculate the remaining second motor phase current based on the obtained at least one second motor phase current and the first motor phase current.

[0016] According to one embodiment of the present invention, the control unit is further configured to store at least one of the plurality of first motor phase currents according to the target current interval when the first motor phase current includes a plurality of currents and the second motor phase current includes a single current.

[0017] According to one embodiment of the present invention, the target sampling period includes multiple periods, and the control unit is further used to: sample and obtain at least one first motor phase voltage sampling value in each target time period within at least one target sampling period of each phase bridge arm, and calculate the motor phase voltage sampling value of the corresponding bridge arm based on the at least one first motor phase voltage sampling value.

[0018] According to one embodiment of the present invention, the sampling unit includes:

[0019] Multiple voltage sampling circuits, each of which is connected to a phase voltage sampling point of a multi-phase bridge arm, and each voltage sampling circuit is used to sample the motor phase voltage of the corresponding bridge arm to obtain an analog voltage;

[0020] The analog-to-digital converter is connected to multiple voltage sampling circuits and the control unit respectively. The reference ground terminal of the analog-to-digital converter is connected to the reference voltage providing unit, and is used to convert the analog voltage based on the voltage division to obtain the motor phase voltage sampling value.

[0021] To achieve the above-mentioned object, a second embodiment of the present invention provides a motor controller, comprising the aforementioned motor phase current sampling device.

[0022] According to the motor controller of the embodiment of the present invention, the motor phase current sampling device mentioned above can realize the sampling function of the motor phase current without phase shifting, thereby avoiding the problem of harmonics generated by the motor controller due to phase current sampling, and the phase current sampling method is simple and easy to implement, thereby reducing the motor phase current sampling cost of the motor controller.

[0023] To achieve the above-mentioned purpose, a third embodiment of the present invention provides a chip, including the aforementioned motor phase current sampling device, or the aforementioned motor controller.

[0024] According to the chip of the embodiment of the present invention, through the aforementioned motor phase current sampling device or the aforementioned motor controller, the sampling function of the motor phase current can be realized without phase shifting and sampling point calculation, thereby avoiding the problem of harmonics generated by the motor controller due to phase current sampling. In addition, the algorithm is simple and the chip computing power requirements are low, thereby reducing the motor phase current sampling cost of the chip.

[0025] To achieve the above-mentioned purpose, a fourth embodiment of the present invention provides an electrical device, including the aforementioned motor phase current sampling device, or the aforementioned motor controller, or the aforementioned chip.

[0026] According to the electrical equipment of the embodiment of the present invention, through the aforementioned motor phase current sampling device or the aforementioned motor controller or the aforementioned chip, the phase current sampling function of the motor in the electrical equipment can be realized without phase shifting, thereby avoiding the problem of harmonics generated by phase current sampling, and the phase current sampling method is simple and easy to implement, thereby reducing the motor phase current sampling cost of the electrical equipment.

[0027] To achieve the above-mentioned purpose, the fifth embodiment of the present invention proposes a motor phase current sampling method, which is applied to a motor controller. The motor controller includes a multi-phase bridge arm, a reference voltage providing unit and a sampling unit. The reference voltage providing unit is connected to the reference ground terminal of the sampling unit and is used to output the divided voltage of the motor neutral point voltage to the reference ground terminal of the sampling unit. The method includes: in a pulse modulation cycle, within the target sampling period of each phase bridge arm, controlling the reference voltage providing unit to output the corresponding divided voltage of the motor neutral point voltage, and controlling the sampling unit to sample the corresponding motor phase voltage based on the divided voltage to obtain multiple motor phase voltage sampling values; wherein the target sampling period is the period from the start of the dead time corresponding to each phase bridge arm to the completion of the freewheeling; determining the motor phase current based on the multiple motor phase voltage sampling values.

[0028] According to the motor phase current sampling method of an embodiment of the present invention, a reference voltage providing unit is controlled to output a corresponding divided voltage of the motor neutral point voltage within a target sampling period of each phase bridge arm in a pulse modulation cycle, and a sampling unit is controlled to sample the corresponding motor phase voltage based on the divided voltage to obtain a plurality of motor phase voltage sampling values, and then the motor phase current is determined based on the plurality of motor phase voltage sampling values, thereby realizing the sampling function of the motor phase current without the need for phase shifting and sampling point calculation, avoiding the problem of possible generation of harmonics that interfere with the operation of the motor, and the algorithm is simple and consumes less computing resources, thereby effectively reducing the phase current sampling cost of the motor.

[0029] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is a schematic structural diagram of a motor controller according to an embodiment of the present invention;

[0031] Figure 2 2 is a schematic structural diagram of a motor phase current sampling device according to an embodiment of the present invention;

[0032] Figure 3 Schematic diagram of the duty cycle of a multi-phase bridge arm in a single pulse modulation cycle according to an embodiment of the present invention;

[0033] Figure 4 2 is a schematic structural diagram of a motor phase current sampling device according to another embodiment of the present invention;

[0034] Figure 5 This is a structural diagram of a reference voltage providing unit according to an embodiment of the present invention;

[0035] Figure 6 A schematic diagram of dividing multiple current intervals of a motor according to an embodiment of the present invention;

[0036] Figure 7 is a circuit diagram of a sampling unit according to an embodiment of the present invention;

[0037] Figure 8 is a schematic structural diagram of a motor controller according to some embodiments of the present invention;

[0038] Figures 9a-9b is a schematic structural diagram of a chip according to some embodiments of the present invention;

[0039] Figures 10a to 10c is a schematic structural diagram of an electrical device according to some embodiments of the present invention;

[0040] Figure 11 Flowchart of a motor phase current sampling method according to an embodiment of the present invention. DETAILED DESCRIPTION

[0041] The following describes embodiments of the present invention in detail, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and are not to be construed as limiting the present invention.

[0042] The following describes a motor phase current sampling device, a motor controller, a chip and an electrical device, and a motor phase current sampling method proposed in embodiments of the present invention with reference to the accompanying drawings.

[0043] It should be noted that the motor phase current sampling device of the embodiment of the present invention can be applied to a motor controller with a multi-phase bridge arm. Figure 1 The motor controller shown in FIG. 1 is used as an example to illustrate the motor phase current sampling method according to an embodiment of the present invention. Figure 1 As shown, the motor controller 100 includes three-phase bridge arms, namely a U-phase bridge arm, a W-phase bridge arm, and a V-phase bridge arm, which are connected to one end of the U-phase winding U, the W-phase winding W, and the V-phase winding V of the motor M. The other ends of the U-phase winding U, the W-phase winding W, and the V-phase winding V are connected and have a motor center point N. Each phase bridge arm includes an upper bridge arm and a lower bridge arm, and the upper bridge arms of the three-phase bridge arms are all connected to the DC bus power supply VBUS, and the lower bridge arms of the three-phase bridge arms are all grounded GND. The upper bridge arm also includes an upper bridge arm switch tube QU with a freewheeling diode in parallel, and the lower bridge arm also includes a lower bridge arm switch tube QD with a freewheeling diode in parallel.

[0044] Specifically, refer to Figure 1As shown, the motor controller 100 constitutes a typical three-phase inverter circuit. By controlling the on-off of the six switching tubes in the three-phase bridge arm, the motor controller 100 can convert the DC power provided by the DC bus power supply VBUS into three-phase AC power, and then control the rotation of the motor M to realize the control function of the motor. The specific control logic is not expanded here.

[0045] Figure 2 is a schematic diagram of the structure of a motor phase current sampling device according to an embodiment of the present invention, referring to Figure 2 As shown, the device includes: a reference voltage providing unit 210 , a sampling unit 220 and a control unit 230 .

[0046] Among them, the reference voltage providing unit 210 is connected to the reference ground terminal VSS of the sampling unit 220, and the control unit 230 is connected to the sampling unit 220; the reference voltage providing unit 210 is used to output the divided voltage of the motor neutral point voltage; the sampling unit 220 is used to sample the motor phase voltage corresponding to each phase bridge arm in the multi-phase bridge arm based on the divided voltage; the control unit 230 is used to control the reference voltage providing unit 210 to output the corresponding divided voltage of the motor neutral point voltage within the target sampling period of each phase bridge arm in a pulse modulation cycle, and control the sampling unit 220 to sample the corresponding motor phase voltage based on the divided voltage, to obtain multiple motor phase voltage sampling values, and to determine the motor phase current based on the multiple motor phase voltage sampling values; wherein, the target sampling period is the period from the dead time corresponding to each phase bridge arm to the completion of the freewheeling.

[0047] Specifically, the pulse modulation period refers to the carrier period of the pulse modulation method, wherein the pulse modulation method is a voltage output modulation method of the motor controller 100, which can be divided into PWM (Pulse Width Modulation, pulse width modulation), PAM (Pulse Amplitude Modulation, pulse amplitude modulation), etc. according to the changed pulse properties. Taking the PWM modulation method as an example, a pulse modulation period is Figure 3 The triangle wave period T0~T1 is shown. Dead time refers to the off period set artificially when the upper bridge switch and the lower bridge switch of the single-phase bridge arm are switched on to avoid the problem of the upper bridge switch and the lower bridge switch being turned on at the same time, such as Figure 3 The periods t0 to t2 and t3 to t5 shown are the dead time of the U-phase bridge arm. After the dead time of each phase bridge arm begins, the freewheeling diode in that phase bridge arm will continue to flow to ensure stable operation of the motor. The target sampling period refers to the period from the start of the corresponding dead time to the completion of the freewheeling of each phase bridge arm. For example, Figure 3The t0~t1 period and t3~t4 period shown are the target sampling periods of the U-phase bridge arm. During the target sampling period of each phase bridge arm, since the freewheeling diode has not yet completed freewheeling, no freewheeling current is generated in the freewheeling diode, and the upper and lower bridge switches of the phase bridge arm are both in the off state, so the phase bridge arm can be regarded as a high-resistance state. At this time, the phase current on the motor winding corresponding to the phase bridge arm still maintains the current magnitude before the start of the dead time due to the inductance characteristics of the motor winding, thereby generating a corresponding voltage drop. Therefore, when the direction of the motor phase current corresponding to a phase bridge arm is from the motor controller 100 to the motor M, the motor phase voltage corresponding to the phase bridge arm in the target sampling period can be expressed as the following formula (1):

[0048] U1=U2+I*R (1)

[0049] Among them, U1 is the motor phase voltage corresponding to a certain phase bridge arm, U2 is the motor neutral point voltage, I is the motor phase current corresponding to the phase bridge arm, and R is the resistance of the motor winding corresponding to the phase bridge arm.

[0050] When the direction of the motor phase current corresponding to a certain phase bridge arm is from the motor M to the motor controller 100, the motor phase voltage corresponding to the phase bridge arm in the target sampling period can be expressed as the following formula (2):

[0051] U1=U2-I*R (2)

[0052] The various symbols have the same meaning as those in the above formula (1) and are not repeated here. From the above formulas (1) and (2), it can be seen that the corresponding motor phase current can be calculated by obtaining the voltage drop generated by the phase current on the motor winding corresponding to each phase bridge arm at the target sampling time within a pulse cycle.

[0053] Therefore, in the embodiment of the present invention, reference Figure 2 As shown, the reference ground terminal VSS of sampling unit 220 is connected to reference voltage providing unit 210. During the target sampling period of each phase bridge arm in a pulse modulation cycle, control unit 230 can control reference voltage providing unit 210 to output the corresponding divided voltage of the motor neutral point voltage during the target sampling period to sampling unit 220. The voltage division ratio of the divided voltage output by reference voltage providing unit 210 can be determined based on the sampling voltage division ratio of sampling unit 220. At this time, the motor phase voltage sampled values ​​sampled by sampling unit 220 are equal to the divided voltage generated by the motor phase current corresponding to each phase bridge arm. Therefore, the motor phase voltage corresponding to each phase bridge arm can be determined based on the multiple motor phase voltage sampled values ​​and the voltage division ratio of sampling unit 220, and further the motor phase current corresponding to each phase bridge arm can be determined. In this way, device 200 realizes the function of sampling motor phase current.

[0054] In the current sampling method of the related art, such as single-resistance sampling, it is not only necessary to set up a sampling resistor and a corresponding operational amplifier circuit, but also to determine the phase shift method and calculate the corresponding sampling points according to the duty cycle of the multi-phase bridge arm in each pulse modulation cycle, which will increase the computing resource consumption of the phase current sampling. At the same time, the phase shift will also generate harmonic noise and affect the operation of the motor. When the single-resistance sampling method is applied, the motor controller 100 may require an additional denoising unit to remove the harmonic effects brought by the single-resistance sampling. Therefore, the phase current sampling cost brought by the single-resistance sampling method is relatively high. In addition, since the single-resistance sampling method has relevant requirements for the duty cycle size, it cannot be applied to low-speed and light-load scenarios, and its applicability is relatively poor. In the phase current sampling device 200 of the embodiment of the present invention, not only is there no need to perform phase shift and sampling point calculations, the algorithm is relatively simple, the computing resource consumption is small, and the problem of possible harmonic generation that interferes with the operation of the motor is avoided, thereby effectively reducing the phase current sampling cost of the motor. In addition, the phase current sampling device 200 of the embodiment of the present invention performs phase voltage sampling within the dead time and has no rigid requirement on the duty cycle, so it can be applied in low-speed and light-load scenarios, and thus has an advantage in applicability.

[0055] In the above embodiment, a reference voltage providing unit, a sampling unit and a control unit are provided in the device, wherein the reference voltage providing unit is connected to the reference ground terminal of the sampling unit, and the control unit is connected to the sampling unit. The control unit can control the reference voltage providing unit to output the corresponding divided voltage of the motor neutral point voltage within the target sampling period of each phase bridge arm in a pulse modulation cycle, and control the sampling unit to sample the corresponding motor phase voltage based on the divided voltage to obtain multiple motor phase voltage sampling values, and determine the motor phase current based on the multiple motor phase voltage sampling values, thereby realizing the sampling function of the motor phase current without the need for phase shifting and sampling point calculation, avoiding the problem of possible generation of harmonics and interference with the operation of the motor, and the algorithm is simple and consumes less computing resources, thereby effectively reducing the phase current sampling cost of the motor.

[0056] In some embodiments, reference Figure 4 As shown, the reference voltage providing unit 210 includes: a digital-to-analog conversion unit 211, which is respectively connected to the reference ground terminal VSS of the sampling unit 220 and the control unit 230, wherein the control unit 230 is used to output a divided digital signal to the digital-to-analog conversion unit 211, so that the digital-to-analog conversion unit 211 converts the digital signal and outputs the divided voltage.

[0057] Specifically, refer to Figure 4As shown, during the target sampling time of each phase bridge arm, the control unit 230 can output a digital signal of the motor neutral point voltage divided voltage corresponding to the target sampling time to the digital-to-analog conversion unit 211. The digital-to-analog conversion unit 211 converts the digital signal to output the corresponding motor neutral point voltage divided voltage to the reference ground terminal VSS of the sampling unit 220, thereby realizing the motor neutral point voltage divided voltage providing function of the reference voltage providing unit 210. At the same time, the digital-to-analog conversion unit 211 also has the advantages of easy debugging and good adaptability. In addition, since the device 200 of the embodiment of the present invention only needs to use the digital-to-analog conversion unit 211 during the target sampling period, the device 200 can directly reuse the existing digital-to-analog converter as the digital-to-analog conversion unit 211, thereby further reducing the hardware cost of the device.

[0058] In some embodiments, reference Figure 5 As shown, the reference voltage providing unit 210 includes: a voltage divider circuit 212 and a controllable switch 213, the controllable switch 213 is respectively connected to the voltage divider circuit 212, the reference ground terminal VSS of the sampling unit 220 and the control unit 230, wherein the control unit 230 is used to control the controllable switch 213 so that the voltage divider circuit 212 outputs the divided voltage.

[0059] Specifically, at the target sampling time of each phase bridge arm, the control unit 230 can control the controllable switch 213 to different gears according to the motor neutral point voltage corresponding to the target sampling time, so as to adjust the connection relationship of multiple resistors in the voltage divider circuit 212, so that the voltage divider circuit 212 outputs the corresponding divided voltage of the motor neutral point voltage. The voltage divider circuit 212 may include multiple types, for example, Figure 5 As shown, the voltage divider circuit 212 may include multiple resistors R1-RN, which are sequentially connected in series between the DC bus power supply VBUS and the ground terminal GND and have multiple nodes J1-JN. The fixed end of the controllable switch 213 is connected to the reference ground terminal VSS of the sampling unit 220, and the moving end of the controllable switch 213 is respectively connected to the nodes J1-JN between the multiple resistors R1-RN. The control unit 230 can control the fixed end of the controllable switch 213 to be connected to the multiple nodes J1-JN according to the motor neutral point voltage corresponding to the target sampling time, and then output the corresponding motor neutral point voltage to the reference ground terminal VSS of the sampling unit 220.

[0060] In some embodiments, the control unit 230 is further configured to determine the divided voltage of the neutral point voltage of the motor within the target sampling period based on the duty cycle of the multi-phase bridge arm during the pulse modulation period.

[0061] Specifically, the control unit 230 can determine the conduction relationship between the upper bridge switch tube QU and the lower bridge switch tube QD of the multi-phase bridge arm according to the duty cycle of the multi-phase bridge arm, and then determine the connection relationship between the motor controller 100 and the multi-phase winding in the motor M, thereby determining the neutral point voltage of the motor within the target sampling period. Subsequently, the control unit 230 can determine the voltage division of the neutral point voltage of the motor within the target sampling period according to the voltage division ratio of the sampling unit 220 and the neutral point voltage of the motor within the target sampling period.

[0062] Furthermore, the multi-phase bridge arm includes a three-phase bridge arm, and the duty cycle includes a minimum duty cycle, an intermediate duty cycle and a maximum duty cycle, wherein the control unit 230 is specifically used to: determine that the voltage division of the motor neutral point voltage within the target sampling period of the bridge arm corresponding to the minimum duty cycle is the voltage division of the DC bus voltage of the motor controller 100; determine that the voltage division of the motor neutral point voltage within the target sampling period of the bridge arm corresponding to the intermediate duty cycle is one half of the voltage division of the DC bus voltage; determine that the voltage division of the motor neutral point voltage within the target sampling period of the bridge arm corresponding to the maximum duty cycle is zero.

[0063] Specifically, in a three-phase motor, the neutral point voltage of the motor can be determined by analyzing the connection relationship of the three-phase bridge arms in different time periods. Figure 1 In the three-phase motor shown, when the upper switching transistors QU are turned on in all three bridge arms, the motor's neutral point N is connected to the DC bus power supply VBUS through the three-phase windings, and the motor's neutral point voltage equals the DC bus voltage. When the upper switching transistors QU are turned on in two of the three bridge arms and the lower switching transistor QD is turned on in one bridge arm, the motor's neutral point is connected to the DC bus power supply VBUS through the two windings corresponding to the upper switching transistors in the bridge arms, and is also connected to ground GND through the winding corresponding to the lower switching transistor in the bridge arm. Since the internal resistance of the three motor windings is the same, according to the voltage divider principle, the motor's neutral point voltage is equal to two-thirds of the DC bus voltage. When the upper switching transistor QU in one of the three-phase bridge arms is turned on, and the lower switching transistors QD in two of the three-phase bridge arms are turned on, the motor's neutral point is connected to the DC bus power supply VBUS through the winding corresponding to the upper switching transistor in the bridge arm, and is also connected to ground GND through the windings corresponding to the lower switching transistors in the bridge arm. Based on the voltage divider principle, the motor's neutral point voltage is equal to one-third of the DC bus voltage. When the lower switching transistors QD in all three-phase bridge arms are turned on, the motor's neutral point is connected to ground GND through the three-phase windings, and the motor's neutral point voltage is zero.

[0064] Therefore, in the embodiment of the present invention, the duty cycle of the three-phase bridge arm and the bridge arm corresponding to the minimum duty cycle, the intermediate duty cycle and the maximum duty cycle can be determined first, wherein the duty cycle of the three-phase bridge arm can be determined according to the motor control algorithm. For example, when the SVPWM (Space Vector Pulse Width Modulation) algorithm is used to control the three-phase motor, the duty cycle of the three-phase bridge arm can be as follows: Figure 3 As shown. Then, the corresponding motor neutral point voltage can be determined based on the connection relationship analysis within the motor controller 100 during the target sampling period of each phase bridge arm. For example, in the bridge arm corresponding to the minimum duty cycle, as shown in FIG. Figure 3 During the target sampling period of the U-phase bridge arm shown, both the upper and lower bridge switches of the U-phase bridge arm are turned off, while the upper bridge switches QU of the V-phase and W-phase bridge arms are turned on. Since the freewheeling diode in the U-phase bridge arm does not freewheel during the target sampling period, the U-phase bridge arm can be considered to be in a high-impedance state. Therefore, the neutral point of the motor can be connected to the DC bus power supply VBUS through the V-phase winding and the W-phase winding. Therefore, the neutral point voltage of the motor at this time is the DC bus voltage of the motor controller 100. Therefore, the control unit 230 can determine the divided voltage of the neutral point voltage of the motor during the target sampling period corresponding to the bridge arm with the minimum duty cycle as the divided voltage of the DC bus voltage of the motor controller 100.

[0065] In the bridge arm corresponding to the middle duty cycle, such as Figure 3 During the target sampling period of the V-phase bridge arm shown, both the upper and lower bridge switches of the V-phase bridge arm are off, the lower bridge switch QD of the U-phase bridge arm is on, and the upper bridge switch QU of the W-phase bridge arm is on. At this point, the V-phase bridge arm can be considered to be in a high-impedance state. Therefore, the DC bus power supply VBUS is grounded through the W-phase winding, the motor neutral point, and the U-phase winding. According to the voltage divider principle, the motor neutral point voltage at this point is half the DC bus voltage. Therefore, the control unit 230 can determine that the motor neutral point voltage during the target sampling period of the bridge arm corresponding to the intermediate duty cycle is half the DC bus voltage.

[0066] In the bridge arm corresponding to the maximum duty cycle, such as Figure 3 During the target sampling period of the W-phase bridge arm shown, both the upper and lower bridge switches of the W-phase bridge arm are off, while the lower bridge switches QD of the U-phase and V-phase bridge arms are on. At this time, the neutral point of the motor is grounded through the U-phase winding and the V-phase winding, and the neutral point voltage of the motor is zero. Therefore, the control unit 230 can determine that the motor neutral point voltage divided by zero during the target sampling period of the bridge arm corresponding to the maximum duty cycle is zero. This enables the control unit to determine the motor neutral point voltage divided by zero during the target sampling period based on the duty cycle of the multi-phase bridge arm.

[0067] In some embodiments, the power frequency cycle of the motor M is divided into multiple current intervals, and the control unit 230 is used to determine the target current interval based on multiple motor phase voltage sampling values, and calculate the positive values ​​of the multiple motor phase voltage sampling values ​​and the motor winding resistance to obtain at least one first motor phase current, and reconstruct at least one second motor phase current based on at least one first motor phase current and the target current interval.

[0068] Specifically, after the sampling unit 220 samples and obtains multiple motor phase voltage sample values, the control unit 230 can determine the motor phase current corresponding to each phase bridge arm based on the multiple motor phase voltage sample values ​​and the corresponding motor winding resistance. However, when the direction of the motor phase current corresponding to a single-phase bridge arm is from the motor M to the motor controller 100, the motor phase voltage corresponding to that phase bridge arm is lower than the motor neutral point voltage. The theoretical phase voltage sample value of the sampling unit 220 is a negative value, and the sampling unit 220 is generally unable to collect negative voltages. Therefore, the phase voltage sample value corresponding to that phase bridge arm collected by the sampling unit 220 is zero. At this time, it is obviously impossible to calculate the actual phase voltage corresponding to that phase bridge arm based on the phase voltage sample value. In a pulse modulation cycle, the multiple phase voltage sample values ​​obtained by the sampling unit 220 include at least one positive value and at least one zero. Therefore, in a pulse modulation cycle, the control unit 230 cannot directly calculate the motor phase current corresponding to the multi-phase bridge arm based on the multiple motor phase voltage sample values ​​and the corresponding motor winding resistance.

[0069] Therefore, in an embodiment of the present invention, the control unit 230 can divide the motor phase current corresponding to the multi-phase bridge arm into a first motor phase current and a second motor phase current, wherein the phase voltage sampling value corresponding to the first motor phase current is a positive value and can be directly calculated using the corresponding motor phase voltage sampling value and the motor winding resistance. The phase voltage sampling value corresponding to the second motor phase current is zero, and the second motor phase current can be obtained by reconstructing the waveform of the first motor phase current and the multi-phase phase voltage or phase current of the motor M. At the same time, in different periods of the power frequency cycle of the motor M, the multi-phase phase voltage or phase current waveform of the motor M is also different, and the corresponding reconstruction method of the second motor phase current is also different. Therefore, the power frequency cycle of the motor M can be uniformly divided into multiple current intervals in advance based on criteria such as the phase switching time and the number of first motor phase currents. When the device 200 samples the motor phase current, the control unit 230 can determine the current interval to which the current pulse cycle belongs, that is, the target current interval, based on the multiple motor phase voltage sampling values ​​obtained. Subsequently, at least one first motor phase current is calculated based on the positive values ​​of multiple motor phase voltage sampling values ​​and the motor winding resistance, and then at least one second motor phase current is reconstructed based on the determined at least one first motor phase current and the target current interval. As a result, the control unit realizes the function of determining the motor phase current corresponding to the multi-phase bridge arm.

[0070] Furthermore, the multi-phase bridge arm is a three-phase bridge arm, and the control unit 230 is specifically used to: when the first motor phase current includes multiple and the second motor phase current includes one, calculate the second motor phase current based on the multiple first motor phase currents; when the first motor phase current includes one and the second motor phase current includes multiple, obtain at least one second motor phase current from the previous current interval according to the target current interval, and calculate the remaining second motor phase current based on the obtained at least one second motor phase current and the first motor phase current.

[0071] Furthermore, the control unit 230 is further configured to store at least one of the plurality of first motor phase currents according to the target current interval when the first motor phase current includes a plurality of phase currents and the second motor phase current includes a single phase current.

[0072] Specifically, when the multi-phase bridge arm is a three-phase bridge arm, the three-phase voltage waveform of the motor can be as follows: Figure 6 As shown, at this time, the motor's power frequency cycle can be evenly divided into 6 current intervals, and each current interval occupies a phase angle range of 60°, as shown in Figure 6 In actual operation, the control unit 230 may determine a target current interval based on the first motor phase current and the second motor phase current, and then reconstruct the second motor phase current based on the determined target current interval to determine the three-phase current of the motor. The specific method for determining the three-phase current is as follows:

[0073] When the target current range is Figure 6 In the first current interval shown, the motor phase current corresponding to the U-phase bridge arm and the motor phase current corresponding to the V-phase bridge arm are the first motor phase currents, which can be directly calculated based on the corresponding phase voltage sampling values ​​and the motor winding resistance. The motor phase current corresponding to the W-phase bridge arm is the second motor phase current, which can be determined according to the following formula (3):

[0074] Ic=0-Ia-Ib (3)

[0075] Among them, Ic is the motor phase current corresponding to the W-phase bridge arm, Ia is the motor phase current corresponding to the U-phase bridge arm, and Ib is the motor phase current corresponding to the V-phase bridge arm. In this way, the function of determining the three-phase current corresponding to the three-phase bridge arm in the first current interval is realized. At the same time, the control unit 220 can also store at least one of the multiple first motor phase currents, for example, only store the motor phase current corresponding to the U-phase bridge arm, so as to be used in subsequent table lookup. Among them, the data storage method of the control unit 230 can be multiple, for example, the motor phase current parameters are stored in the buffer register of the control unit 230; the size of the storage area can be pre-set according to the sampling frequency in the first interval, for example, the storage area can be set to 1000, and in the first current interval, the control unit 230 can store the sampled motor phase current corresponding to the U-phase bridge arm in the buffer register in chronological order.

[0076] When the target current range is Figure 6 In the second current interval shown, the motor phase current corresponding to the W-phase bridge arm is the first motor phase current, which can be directly calculated based on the corresponding phase voltage sampling value and the motor winding resistance. The motor phase current corresponding to the U-phase bridge arm and the motor phase current corresponding to the V-phase bridge arm are the second motor phase currents. Among them, the control unit 230 can obtain at least one of the second motor phase currents based on the motor phase current parameters stored by the control unit 230 in the previous current interval, and calculate the remaining second motor phase currents based on the obtained at least one second motor phase current and the first motor phase current. For example, according to Figure 6 As shown in the three-phase voltage waveform of the second current interval, it can be seen that the motor phase voltage corresponding to the U-phase bridge arm in the second current interval is inversely proportional to the motor phase voltage corresponding to the U-phase bridge arm in the previous current interval, and the motor phase voltage corresponding to the V-phase bridge arm in the second current interval is also inversely proportional to the motor phase voltage corresponding to the V-phase bridge arm in the previous current interval. At this time, the motor phase voltage and motor phase current corresponding to each phase bridge arm are proportional. Therefore, at least one motor phase current can be obtained by performing data processing on the motor phase current parameters stored by the control unit 230 in the previous current interval. For example, when the control unit 230 stores the motor phase current corresponding to the U-phase bridge arm in the first current interval, in the second current interval, the control unit 230 can read the buffer register by reverse table lookup, and then add a negative sign to the obtained motor phase current parameters to obtain the motor phase current Ia corresponding to the U-phase bridge arm in the second current interval. Subsequently, the motor phase current corresponding to the V-phase bridge arm can be determined according to the following formula (4):

[0077] Ib=0-Ia-Ic (4)

[0078] Wherein, Ib is the motor phase current corresponding to the V-phase bridge arm, Ia is the motor phase current corresponding to the U-phase bridge arm, and Ic is the motor phase current corresponding to the W-phase bridge arm. Thus, the function of determining the three-phase current of the motor within the second current interval is achieved. Optionally, when the control unit 230 uses a buffer register to store motor phase current parameters, the control unit 230 may clear the register after obtaining at least one second motor phase current from the previous current interval according to the target current interval, so that the buffer register can be reused in subsequent cycles, thereby improving the working efficiency of the control unit 230.

[0079] It should be noted that the method for determining the motor phase current in the third current interval and the fifth current interval is similar to that in the first current interval, and the method for determining the motor phase current in the fourth current interval and the sixth current interval is similar to that in the second current interval, which will not be described in detail here.

[0080] Optionally, before sampling phase currents, the control unit 230 may start the motor using an open-voltage loop and run the motor for at least one power frequency cycle to obtain symmetrical three-phase AC power, thereby ensuring the accuracy of the phase current reconstruction. Furthermore, after completing one power frequency cycle of motor phase current sampling, the control unit 230 may control the motor to switch from open-voltage loop to open-current loop operation based on stable phase current acquisition, thereby completing the current closed loop.

[0081] In some embodiments, the target sampling period includes multiple periods, and the control unit 230 is further used to: sample at least one first motor phase voltage sampling value in each target time period within at least one target sampling period of each phase bridge arm, and calculate the motor phase voltage sampling value of the corresponding bridge arm based on the at least one first motor phase voltage sampling value.

[0082] Specifically, refer to Figure 3 As shown, there is a target sampling period within each dead time of each phase bridge arm. Therefore, when sampling the motor phase voltage corresponding to each phase bridge arm, the control unit 230 can perform one or more samplings within each target time period within one or more target sampling periods of each phase bridge arm to obtain one or more first motor phase voltage sampling values. After obtaining one or more first motor phase voltage sampling values, the control unit 230 can obtain the motor phase voltage sampling value corresponding to the phase bridge arm by averaging, etc., thereby improving the sampling accuracy. The more first motor phase voltage sampling values ​​obtained, the higher the accuracy of the finally determined motor phase voltage sampling value. The specific number of sampling times can be determined based on actual needs and the length of the target sampling period.

[0083] It should be noted that one or more first motor phase voltage sampling values ​​may be processed in other ways to obtain the motor phase voltage sampling value corresponding to each phase bridge arm, such as interpolation method, etc., which is not specifically limited here.

[0084] In some embodiments, reference Figure 4 As shown, the sampling unit 220 includes: multiple voltage sampling circuits 221 and an analog-to-digital converter ADC. The multiple voltage sampling circuits 221 are correspondingly connected to the phase voltage sampling points JU~JX of the multi-phase bridge arms in the motor controller 100. Each voltage sampling circuit 221 is used to sample the motor phase voltage of the corresponding bridge arm to obtain an analog voltage; the analog-to-digital converter ADC is respectively connected to the multiple voltage sampling circuits 221 and the control unit 230, and the reference ground terminal VSS of the analog-to-digital converter ADC is connected to the reference voltage providing unit 210, and is used to convert the analog voltage based on voltage division to obtain a motor phase voltage sampling value.

[0085] Specifically, the voltage sampling circuit 221 is primarily used to sample the motor phase voltage of the corresponding bridge arm through voltage division or other methods to obtain an analog voltage. During the target sampling period of each bridge arm, the control unit 230 can control the reference voltage providing unit 210 to input the corresponding divided voltage of the motor neutral point voltage to the reference ground terminal VSS of the analog-to-digital converter ADC, thereby causing the analog-to-digital converter ADC to convert the analog voltage to obtain the motor phase voltage sample value. The specific workings of the analog-to-digital converter ADC are not elaborated here.

[0086] In addition, outside the target sampling period of the motor controller 100, the control unit 230 also controls the reference voltage providing unit 210 to connect the reference ground terminal of the analog-to-digital converter ADC to the ground GND, thereby enabling the analog-to-digital converter ADC to perform normal analog-to-digital conversion functions, realizing time division multiplexing of the analog-to-digital converter ADC, thereby improving the efficiency of the analog-to-digital converter ADC, and the device 200 can also multiplex the analog-to-digital converter ADC with other devices, thereby reducing the hardware cost of the device 200.

[0087] For example, when the multi-phase bridge arm is a three-phase bridge arm, refer to Figure 7 As shown, the sampling unit 220 may include three identical voltage sampling circuits 221 and an analog-to-digital converter ADC. The three voltage sampling circuits 221 are respectively connected to the phase voltage sampling points JU, JW, and JV nodes of the three-phase bridge arm, and the corresponding sampling points (Vbemf_U, Vbemf_V, and Vbemf_W) of the three voltage sampling circuits 221 are respectively connected to the three phase voltage sampling terminals of the analog-to-digital converter ADC. The three voltage sampling circuits 221 have the same circuit structure. Taking the voltage sampling circuit 221 of the U-phase bridge arm as an example, the circuit 221 includes first to third resistors R1 to R3 and a capacitor C, wherein one end of the first resistor R1 is grounded to GND, and the other end of the first resistor R1 is connected to one end of the second resistor R2 and one end of the third resistor R3 respectively; the other end of the second resistor R2 is connected to the node JU as a sampling end; the other end of the third resistor R3 is connected to one end of the capacitor C and serves as the U-phase voltage sampling point Vbemf_U, and the other end of the capacitor C is grounded to GND. The circuit mainly samples the motor phase voltage corresponding to the U-phase bridge arm based on the voltage division principle of the first resistor R1 and the second resistor R2. At the same time, the capacitor C has a voltage stabilizing effect, and the third resistor R3 has a current limiting effect to prevent excessive current in the voltage sampling circuit 221.

[0088] Optionally, since it takes a lot of time to obtain the average value through multiple sampling to improve the phase voltage sampling accuracy, a higher resolution analog-to-digital converter (ADC) can also be used to improve the sampling accuracy of the motor phase voltage. Figure 7The voltage sampling circuit 221 shown, the 12-bit analog-to-digital converter ADC can meet the needs of phase voltage sampling. If the accuracy of motor phase voltage sampling needs to be further improved, a 14-bit analog-to-digital converter ADC can be directly used to obtain the phase voltage sampling value, or the dead time can be increased, and the analog-to-digital converter ADC can be set to oversampling. A 13-bit analog-to-digital converter ADC is simulated by accumulating two consecutive samples, or a 14-bit analog-to-digital converter ADC is simulated by accumulating four times. The specific device selection method can be determined comprehensively based on the actual cost requirements and accuracy requirements, and is not limited here.

[0089] In summary, according to an embodiment of the present invention, a motor phase current sampling device is provided in the device by arranging a reference voltage providing unit, a sampling unit and a control unit, wherein the reference voltage providing unit is connected to the reference ground terminal of the sampling unit, and the control unit is connected to the sampling unit. The control unit can control the reference voltage providing unit to output the corresponding motor neutral point voltage divided voltage within the target sampling period of each phase bridge arm in a pulse modulation cycle, and control the sampling unit to sample the corresponding motor phase voltage based on the divided voltage to obtain multiple motor phase voltage sampling values, and determine the motor phase current based on the multiple motor phase voltage sampling values, thereby realizing the sampling function of the motor phase current without the need for phase shifting and sampling point calculation, avoiding the problem of possible generation of harmonics and interference with the motor operation, and the algorithm is simple and consumes less computing resources, thereby effectively reducing the phase current sampling cost of the motor.

[0090] Corresponding to the above embodiment, the embodiment of the present invention further provides a motor controller, referring to Figure 8 As shown, the motor controller 1000 includes the aforementioned motor phase current sampling device 100 .

[0091] According to the motor controller of the embodiment of the present invention, the motor phase current sampling device mentioned above can realize the sampling function of the motor phase current without phase shifting, thereby avoiding the problem of harmonics generated by the motor controller due to phase current sampling, and the phase current sampling method is simple and easy to implement, thereby reducing the motor phase current sampling cost of the motor controller.

[0092] Corresponding to the above embodiment, the embodiment of the present invention further provides a chip, referring to Figures 9a-9b As shown, the chip 2000 includes the aforementioned motor phase current sampling device 200 , or the aforementioned motor controller 1000 .

[0093] The chip according to the embodiment of the present invention includes the motor phase current sampling device in the above embodiment. Here, the chip can be a chip for multiple purposes such as motor control, motor phase current sampling, and motor working status monitoring. These chips can realize the sampling function of the motor phase current through the aforementioned motor phase current sampling device or the aforementioned motor controller without phase shifting and sampling point calculation, thereby avoiding the problem of harmonics generated by phase current sampling in the motor controller. In addition, the algorithm is simple and the chip computing power requirement is low, thereby reducing the motor phase current sampling cost of the chip.

[0094] Corresponding to the above embodiment, the embodiment of the present invention further provides an electrical device, referring to Figures 10a to 10c As shown, the electrical device 3000 includes the aforementioned motor phase current sampling device 200 , or the aforementioned motor controller 1000 , or the aforementioned chip 2000 .

[0095] An electrical device according to an embodiment of the present invention includes the motor phase current sampling device, chip, or motor controller described in any of the above embodiments. The electrical device may be an air conditioner, refrigerator, compressor, or other device. The motor phase current sampling device, motor controller, or chip in these electrical devices can perform phase current sampling of the motor within the electrical device without phase shifting, thereby avoiding the problem of harmonics generated by phase current sampling. Furthermore, the phase current sampling method is simple and easy to implement, thereby reducing the cost of motor phase current sampling in the electrical device.

[0096] Corresponding to the above embodiment, the embodiment of the present invention further provides a motor phase current sampling method, which is applied to a motor controller. The motor controller includes a multi-phase bridge arm, a reference voltage providing unit and a sampling unit. The reference voltage providing unit is connected to the reference ground terminal of the sampling unit and is used to output the divided voltage of the motor neutral point voltage to the reference ground terminal of the sampling unit. Figure 11 As shown, the method includes:

[0097] S11, in one pulse modulation cycle, within the target sampling period of each phase bridge arm, control the reference voltage providing unit to output the corresponding divided voltage of the motor neutral point voltage, and control the sampling unit to sample the corresponding motor phase voltage based on the divided voltage to obtain multiple motor phase voltage sampling values; wherein, the target sampling period is the period from the start of the dead time corresponding to each phase bridge arm to the completion of the freewheeling.

[0098] S12, determining the motor phase current according to the plurality of motor phase voltage sampling values.

[0099] According to an embodiment of the present invention, the method further includes: determining the divided voltage of the neutral point voltage of the motor within the target sampling period based on the duty cycle of the multi-phase bridge arm in the pulse modulation period.

[0100] According to one embodiment of the present invention, the multi-phase bridge arm includes a three-phase bridge arm, and the duty cycle includes a minimum duty cycle, an intermediate duty cycle and a maximum duty cycle, wherein, in the pulse modulation cycle, the voltage division of the neutral point voltage of the motor within the target sampling period is determined based on the duty cycle of the multi-phase bridge arm, including: determining the voltage division of the neutral point voltage of the motor within the target sampling period of the bridge arm corresponding to the minimum duty cycle as the voltage division of the DC bus voltage of the motor controller; determining the voltage division of the neutral point voltage of the motor within the target sampling period of the bridge arm corresponding to the intermediate duty cycle as the voltage division of half the DC bus voltage; and determining the voltage division of the neutral point voltage of the motor within the target sampling period of the bridge arm corresponding to the maximum duty cycle as zero.

[0101] According to one embodiment of the present invention, the power frequency cycle of the motor is divided into multiple current intervals, and the method also includes: determining a target current interval based on multiple motor phase voltage sampling values, and calculating at least one first motor phase current based on the positive values ​​of the multiple motor phase voltage sampling values ​​and the motor winding resistance, and reconstructing at least one second motor phase current based on the at least one first motor phase current and the target current interval.

[0102] According to one embodiment of the present invention, the multi-phase bridge arm is a three-phase bridge arm, and the method further includes: when the first motor phase current includes multiple and the second motor phase current includes one, the second motor phase current is calculated based on the multiple first motor phase currents; when the first motor phase current includes one and the second motor phase current includes multiple, at least one second motor phase current is obtained from the previous current interval according to the target current interval, and the remaining second motor phase current is calculated based on the obtained at least one second motor phase current and the first motor phase current.

[0103] According to an embodiment of the present invention, the method further includes: when the first motor phase current includes a plurality of currents and the second motor phase current includes a single current, storing at least one of the plurality of first motor phase currents according to the target current interval.

[0104] According to one embodiment of the present invention, the target sampling period includes multiple target sampling periods, and the method further includes: sampling to obtain at least one first motor phase voltage sampling value in each target time period within at least one target sampling period of each phase bridge arm, and calculating the motor phase voltage sampling value of the corresponding bridge arm based on the at least one first motor phase voltage sampling value.

[0105] It should be noted that, for the description of the motor phase current sampling method in this application, please refer to the aforementioned description of the motor phase current sampling device, which will not be repeated here.

[0106] According to the motor phase current sampling method of an embodiment of the present invention, a reference voltage providing unit is controlled to output a corresponding divided voltage of the motor neutral point voltage within a target sampling period of each phase bridge arm in a pulse modulation cycle, and a sampling unit is controlled to sample the corresponding motor phase voltage based on the divided voltage to obtain a plurality of motor phase voltage sampling values, and then the motor phase current is determined based on the plurality of motor phase voltage sampling values, thereby realizing the sampling function of the motor phase current without the need for phase shifting and sampling point calculation, avoiding the problem of possible generation of harmonics that interfere with the operation of the motor, and the algorithm is simple and consumes less computing resources, thereby effectively reducing the phase current sampling cost of the motor.

[0107] It should be noted that the logic and / or steps represented in the flowcharts or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing the logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (e.g., a computer-based system, a system including a processor, or other system that can fetch and execute instructions from an instruction execution system, apparatus, or device). For purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transport a program for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (non-exhaustive list) of computer-readable media include the following: an electrical connection with one or more wires (electronic device), a portable computer disk cartridge (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and programmable read-only memory (EPROM or flash memory), fiber optic devices, and portable compact disc read-only memory (CDROM). Furthermore, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium and then editing, interpreting or processing it in another suitable manner if necessary, and then storing it in a computer memory.

[0108] It should be understood that various parts of the present invention can be implemented using hardware, software, firmware, or a combination thereof. In the above-described embodiments, multiple steps or methods can be implemented using software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented using hardware, as in another embodiment, any one of the following technologies known in the art or a combination thereof can be used: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application-specific integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0109] Throughout this specification, references to terms such as "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" indicate that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0110] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0111] In the present invention, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection; direct connection, or indirect connection through an intermediate medium; internal communication between two components, or interaction between two components, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0112] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A motor phase current sampling device, characterized in that: Applied to a motor controller, the motor controller includes a multi-phase bridge arm, the device includes: a reference voltage providing unit, a sampling unit and a control unit, the reference voltage providing unit is connected to the reference ground terminal of the sampling unit, and the control unit is connected to the sampling unit; The reference voltage providing unit is used to output the divided voltage of the neutral point voltage of the motor; The sampling unit is used to sample the motor phase voltage corresponding to each phase bridge arm in the multi-phase bridge arm based on the voltage division; The control unit is used to control the reference voltage providing unit to output the corresponding divided voltage of the motor neutral point voltage within the target sampling period of each phase bridge arm in one pulse modulation cycle, and control the sampling unit to sample the corresponding motor phase voltage based on the divided voltage to obtain multiple motor phase voltage sampling values, and determine the motor phase current based on the multiple motor phase voltage sampling values; wherein the target sampling period is the period from the start of the dead time corresponding to each phase bridge arm to the completion of freewheeling.

2. The device according to claim 1, characterized in that The reference voltage providing unit includes: a digital-to-analog conversion unit, which is connected to the reference ground terminal of the sampling unit and the control unit respectively, wherein the control unit is used to output the divided voltage digital signal to the digital-to-analog conversion unit, so that the digital-to-analog conversion unit converts the digital signal and outputs the divided voltage.

3. The device according to claim 1, characterized in that The reference voltage providing unit includes: a voltage dividing circuit and a controllable switch, wherein the controllable switch is respectively connected to the voltage dividing circuit, the reference ground terminal of the sampling unit and the control unit, wherein the control unit is used to control the controllable switch so that the voltage dividing circuit outputs the divided voltage.

4. The device according to claim 2 or 3, characterized in that The control unit is further configured to determine, during the pulse modulation period, a divided voltage of the neutral point voltage of the motor within the target sampling period based on the duty cycle of the multi-phase bridge arm.

5. The device according to claim 4, characterized in that The multi-phase bridge arm includes a three-phase bridge arm, the duty cycle includes a minimum duty cycle, an intermediate duty cycle, and a maximum duty cycle, wherein the control unit is specifically configured to: Determine the divided voltage of the motor neutral point voltage within the target sampling period of the bridge arm corresponding to the minimum duty cycle as the divided voltage of the DC bus voltage of the motor controller; Determine that the divided voltage of the motor neutral point voltage in the target sampling period of the bridge arm corresponding to the intermediate duty cycle is half of the divided voltage of the DC bus voltage; It is determined that the divided voltage of the neutral point voltage of the motor within the target sampling period of the bridge arm corresponding to the maximum duty cycle is zero.

6. The device according to claim 1, characterized in that The power frequency cycle of the motor is divided into multiple current intervals. The control unit is used to determine a target current interval based on multiple motor phase voltage sampling values, and calculate at least one first motor phase current based on the positive values ​​of the multiple motor phase voltage sampling values ​​and the motor winding resistance, and reconstruct at least one second motor phase current based on the at least one first motor phase current and the target current interval.

7. The device according to claim 6, characterized in that The multi-phase bridge arm is a three-phase bridge arm, and the control unit is specifically configured to: When the first motor phase current includes a plurality of phase currents and the second motor phase current includes a single phase current, the second motor phase current is calculated based on the plurality of first motor phase currents; When the first motor phase current includes one and the second motor phase current includes multiple, at least one second motor phase current is obtained from the previous current interval according to the target current interval, and the remaining second motor phase currents are calculated based on the obtained at least one second motor phase current and the first motor phase current.

8. The device according to claim 7, characterized in that The control unit is further configured to store at least one of the plurality of first motor phase currents according to the target current interval when the first motor phase currents include a plurality and the second motor phase current includes one.

9. The device according to claim 1, characterized in that The target sampling period includes multiple periods, and the control unit is also used to: sample and obtain at least one first motor phase voltage sampling value in each target time period within at least one target sampling period of each phase bridge arm, and calculate the motor phase voltage sampling value of the corresponding bridge arm based on the at least one first motor phase voltage sampling value.

10. The device according to claim 1, characterized in that The sampling unit comprises: A plurality of voltage sampling circuits, each of which is connected to a phase voltage sampling point of each multi-phase bridge arm, and each of which is used to sample the motor phase voltage of the corresponding bridge arm to obtain an analog voltage; An analog-to-digital converter, wherein the analog-to-digital converter is respectively connected to the multiple voltage sampling circuits and the control unit, and the reference ground terminal of the analog-to-digital converter is connected to the reference voltage providing unit, and is used to convert the analog voltage based on the voltage division to obtain the motor phase voltage sampling value.

11. A motor controller, characterized in that: It comprises the motor phase current sampling device according to any one of claims 1-10.

12. A chip, characterized in that: It comprises the motor phase current sampling device according to any one of claims 1 to 10, or the motor controller according to claim 11.

13. An electrical device, characterized in that: It comprises the motor phase current sampling device according to any one of claims 1 to 10, or the motor controller according to claim 11, or the chip according to claim 12.

14. A motor phase current sampling method, characterized in that: Applied to a motor controller, the motor controller includes a multi-phase bridge arm, a reference voltage providing unit, and a sampling unit, the reference voltage providing unit is connected to the reference ground terminal of the sampling unit and is used to output the divided voltage of the motor neutral point voltage to the reference ground terminal of the sampling unit, the method includes: In one pulse modulation cycle, within the target sampling period of each phase bridge arm, the reference voltage providing unit is controlled to output a corresponding divided voltage of the motor neutral point voltage, and the sampling unit is controlled to sample the corresponding motor phase voltage based on the divided voltage to obtain a plurality of motor phase voltage sampling values; wherein the target sampling period is the period from the start of the dead time corresponding to each phase bridge arm to the completion of freewheeling; The motor phase current is determined according to the plurality of motor phase voltage sampling values.

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