Three-phase current sampling method and device of motor, motor controller and storage medium

Abstract

The application discloses a three-phase current sampling method and device of a motor, a motor controller and a storage medium, wherein the three-phase current sampling method of the motor is applied to the motor controller with a double-resistance current detection circuit, and the method comprises the following steps: sampling one-phase current in two-phase currents detected by the double-resistance current detection circuit when a voltage space vector is a zero vector, obtaining a first current sampling value, and sampling the one-phase current detected by the double-resistance current detection circuit when the voltage space vector is an effective vector, obtaining a second current sampling value, wherein the current phase sampled when the voltage space vector is the zero vector is different from the current phase sampled when the voltage space vector is the effective vector; and the three-phase current of the motor is determined according to the first current sampling value and the second current sampling value. According to the method, the two-phase currents in the double-resistance current detection circuit are sampled at the zero vector and the effective vector respectively, and the occupied time of the zero vector is reduced.

Description

Technical Field

[0001] This application relates to the field of motor control technology, and in particular to a three-phase current sampling method, device, motor controller and storage medium for a motor. Background Technology

[0002] Currently, the motors of household appliances such as air conditioners, washing machines, and refrigerators are generally controlled using vector frequency conversion technology, and obtaining the phase current plays a crucial role in vector control. To reduce costs, dual-resistor sampling has a significant cost advantage over triple-resistor sampling.

[0003] To ensure sampling accuracy, current dual-resistor sampling schemes all use zero-vector sampling, which has high requirements for minimum zero-vector time, resulting in reduced voltage utilization. Summary of the Invention

[0004] This invention aims to at least partially solve one of the technical problems in related technologies. To this end, the first objective of this invention is to propose a three-phase current sampling method for a motor, which reduces the zero-vector occupation time and increases the proportion of the effective vector by sampling the two-phase current in a dual-resistance current detection circuit at both the zero-vector and effective vector times, thereby improving voltage utilization.

[0005] A second objective of this invention is to provide a computer-readable storage medium.

[0006] The third objective of this invention is to provide a motor controller.

[0007] The fourth objective of this invention is to provide a three-phase current sampling device for an electric motor.

[0008] To achieve the above objectives, a three-phase current sampling method for a motor is proposed according to a first aspect embodiment of the present invention, applied in a motor controller having a dual-resistance current detection circuit. The method includes: sampling one phase current of the two-phase current detected by the dual-resistance current detection circuit when the voltage space vector is zero, obtaining a first current sampling value; and sampling the one phase current detected by the dual-resistance current detection circuit when the voltage space vector is an effective vector, obtaining a second current sampling value, wherein the phase of the current sampled when the voltage space vector is zero is different from the phase of the current sampled when the voltage space vector is an effective vector; and determining the three-phase current of the motor based on the first current sampling value and the second current sampling value.

[0009] According to an embodiment of the present invention, a three-phase current sampling method for a motor involves sampling one phase current from the two-phase current detected by a dual-resistance current detection circuit when the voltage space vector is zero, obtaining a first current sampling value; and sampling the other phase current detected by the dual-resistance current detection circuit when the voltage space vector is a valid vector, obtaining a second current sampling value. The three-phase current of the motor is then determined based on the first and second current sampling values. Thus, by sampling one phase current in the dual-resistance current detection circuit when the voltage space vector is zero, and sampling the other phase current in the dual-resistance current detection circuit when the voltage space vector is valid, the three-phase current of the motor can be obtained based on the two-phase current sampling values. This reduces the time occupied by the zero vector and increases the proportion of the valid vector, thereby improving voltage utilization.

[0010] According to one embodiment of the present invention, before sampling one phase current of the two-phase current detected by the dual-resistance current detection circuit, the method further includes: determining the sector where the effective vector corresponding to the second current sampling value is located; and determining the phase current to be sampled among the two-phase currents based on the sector where the effective vector corresponding to the second current sampling value is located.

[0011] According to one embodiment of the present invention, the first current sample value is sampled during the triangular wave decrement counting process, and the second current sample value is sampled during the triangular wave increment counting process.

[0012] According to one embodiment of the present invention, sampling one phase current of the two-phase current detected by the dual-resistance current detection circuit when the voltage space vector is zero includes: determining the start time of the zero vector, and sampling one phase current of the two-phase current after a first preset time delay.

[0013] According to one embodiment of the present invention, sampling a phase current detected by a dual-resistance current detection circuit when the voltage space vector is an effective vector includes: determining the start time of switching from the zero vector to the effective vector, and sampling the phase current detected by the dual-resistance current detection circuit after a first preset time delay.

[0014] According to one embodiment of the present invention, both the first current sample value and the second current sample value are sampled during the triangular wave count process.

[0015] According to one embodiment of the present invention, sampling a phase current detected by a dual-resistance current detection circuit when the voltage space vector is an effective vector includes: determining the start time of switching to the effective vector of the current sector, and sampling a phase current detected by the dual-resistance current detection circuit after a first preset time delay.

[0016] According to one embodiment of the present invention, sampling one phase current of the two-phase current detected by the dual-resistance current detection circuit when the voltage space vector is zero includes: determining the start time of switching from the effective vector of the current sector to the zero vector, and sampling one phase current of the two-phase current after a first preset time delay.

[0017] To achieve the above objectives, a computer-readable storage medium is provided according to a second aspect of the present invention, on which a three-phase current sampling program for a motor is stored, which, when executed by a processor, implements the three-phase current sampling method for a motor according to any of the foregoing embodiments.

[0018] According to the computer-readable storage medium of the present invention, by executing the computer program for sampling the three-phase current of the motor described above, the two-phase current in the dual-resistance current detection circuit is sampled at zero vector time and effective vector time respectively, thereby reducing the zero vector occupation time and increasing the proportion of effective vector, thus improving voltage utilization.

[0019] To achieve the above objectives, a motor controller is provided according to a third aspect of the present invention, comprising: a memory, a processor, and a three-phase current sampling program for a motor stored in the memory and executable on the processor. When the processor executes the program, it implements the three-phase current sampling method for a motor according to any of the foregoing embodiments.

[0020] According to the embodiment of the present invention, the motor controller executes a computer program for sampling the three-phase current of the motor through a processor. By sampling the two-phase current in the dual-resistance current detection circuit at zero vector and effective vector respectively, the occupancy time of the zero vector is reduced and the proportion of the effective vector is increased, thereby improving the voltage utilization rate.

[0021] To achieve the above objectives, a three-phase current sampling device for a motor is provided according to a fourth aspect of the present invention, applied in a motor controller having a dual-resistance current detection circuit. The device includes: a current sampling module, used to sample one phase current of the two-phase current detected by the dual-resistance current detection circuit when the voltage space vector is zero, to obtain a first current sampling value, and to sample the one phase current detected by the dual-resistance current detection circuit when the voltage space vector is a valid vector, to obtain a second current sampling value, wherein the phase of the current sampled when the voltage space vector is zero is different from the phase of the current sampled when the voltage space vector is a valid vector; and a determination module, used to determine the three-phase current of the motor based on the first current sampling value and the second current sampling value.

[0022] According to an embodiment of the present invention, a three-phase current sampling device for a motor samples one phase current from the two-phase current detected by a dual-resistance current detection circuit when the voltage space vector is zero, obtaining a first current sampling value. Then, when the voltage space vector is a valid vector, it samples the other phase current detected by the dual-resistance current detection circuit, obtaining a second current sampling value. A determination module then determines the three-phase current of the motor based on the first and second current sampling values. Thus, by sampling one phase current in the dual-resistance current detection circuit when the voltage space vector is zero, and sampling the other phase current when the voltage space vector is valid, the three-phase current of the motor can be obtained from the two-phase current sampling values. This reduces the time occupied by the zero vector and increases the proportion of the valid vector, thereby improving voltage utilization.

[0023] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of a motor control system according to an embodiment of the present invention;

[0025] Figure 2 This is a circuit diagram of a dual-resistance current detection circuit according to an embodiment of the present invention;

[0026] Figure 3 This is a flowchart illustrating a three-phase current sampling method for a motor according to an embodiment of the present invention;

[0027] Figure 4 This is a waveform diagram of the second current sampling value of the motor in sector 3 and sampled during the triangular wave counting process according to an embodiment of the present invention;

[0028] Figure 5 This is a waveform diagram of the second current sampling value of the motor in sector 3 and sampled during the triangular wave count-down process according to an embodiment of the present invention;

[0029] Figure 6 This is a system schematic diagram of a motor controller according to an embodiment of the present invention;

[0030] Figure 7 This is a schematic diagram of the structure of a three-phase current sampling device for a motor according to an embodiment of the present invention. Detailed Implementation

[0031] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0032] The following description, with reference to the accompanying drawings, describes a three-phase current sampling method, apparatus, motor controller, and storage medium for an electric motor according to embodiments of the present invention.

[0033] refer to Figures 1-2 As shown, the motor 20 control system includes an inverter 10, a motor 20, and a motor controller 30. The DC side of the inverter 10 is connected to a DC power supply Vdc. The midpoints of the three-phase bridge arms of the inverter 10 are connected to one end of the three-phase windings of the motor 20, and the other end of the three-phase windings of the motor 20 is connected to form the neutral point of the three-phase windings of the motor 20.

[0034] The motor controller 30 includes a dual-resistor current detection circuit and a control circuit. The dual-resistor current detection circuit includes current-sensing resistors R1 and R2, which are connected between the lower bridge arms of phase u and phase v of the inverter 10 and ground, respectively. The current-sensing resistors R1 and R2 sample the phase u current Iu and phase v current Iv of the inverter 10. It should be noted that the connection method of the current-sensing resistors R1 and R2 is not limited to the above; they can be connected between any two lower bridge arms of the inverter 10 and ground. No specific restrictions are imposed here.

[0035] The control circuit includes a speed loop PI controller 31, a current loop PI controller 32, three coordinate transformation modules 33, an SVPWM (Space Vector Pulse Width Modulation) control module 34, a current sampling and reconstruction module 35, and a position and speed observation module 36. The controller circuit generates six control signals using the SVPWM algorithm based on the current speed, current, and desired speed of the motor 20 to drive the switching transistors in the inverter, thereby enabling the motor 20 to operate.

[0036] Specifically, the three-phase bridge arm currents that can be sampled under different voltage space vectors are shown in Table 1:

[0037] Table 1

[0038] 1 0 0 -Iv, -Iw 1 1 0 -Iw 0 1 0 -Iu,-Iw 0 1 1 -Iu 0 0 1 -Iu, -Iv 1 0 1 -Iv 0 0 0 -Iu, -Iv, -Iw 1 1 1 0

[0039] Because in such Figure 2 In the circuit shown, phase W does not have a current-sensing resistor, so when using... Figure 2 The circuit shown cannot collect the current sampling value of phase W.

[0040] The three-phase current sampling method for the motor in this embodiment is applied to the motor controller with the dual-resistance current detection circuit described above. Figure 3 This is a flowchart illustrating a three-phase current sampling method for a motor according to an embodiment of the present invention, as shown below. Figure 3 As shown, the three-phase current sampling method for the motor includes:

[0041] S101, when the voltage space vector is zero, sample one phase current of the two phase currents detected by the dual-resistance current detection circuit to obtain a first current sampling value, and when the voltage space vector is an effective vector, sample one phase current detected by the dual-resistance current detection circuit to obtain a second current sampling value. The current phase sampled when the voltage space vector is zero is different from the current phase sampled when the voltage space vector is an effective vector.

[0042] To simplify the description, the following will all use the format of "..." Figure 2 The example shown is used for illustration.

[0043] Specifically, when the voltage space vector is zero (000), as shown in Table 1, the dual-resistance current detection circuit can sample the u-phase current Iu and the v-phase current Iv. Taking the sampling of the u-phase current Iu as an example, the u-phase current Iu detected by the dual-resistance current detection circuit is sampled to obtain the first current sampling value -Iu. When the voltage space vector is a valid vector (which is a vector that is neither 000 nor 111), the v-phase current Iv detected by the dual-resistance current detection circuit is sampled to obtain the second current sampling value -Iv.

[0044] It should be noted that the time interval between the sampling time of the first current sample value and the sampling time of the second current sample value is greater than the preset sampling time length, which is obtained based on the chip's minimum sampling time.

[0045] In one alternative implementation, during zero-vector sampling, the zero-vector region of two adjacent PWM (Pulse Width Modulation) cycles can be used as a current sampling window, thereby further shortening the zero-vector duration.

[0046] In some embodiments, before sampling one of the two-phase currents detected by the dual-resistance current detection circuit, the method further includes: determining the sector where the effective vector corresponding to the second current sampling value is located; and determining the one phase current to be sampled from the two-phase currents based on the sector where the effective vector corresponding to the second current sampling value is located.

[0047] Specifically, the sector is determined based on the effective vector corresponding to the second current sampling value. Then, the basic effective vector corresponding to the sector is determined. Based on the basic effective vector, it is determined which phase lower bridge switch is in the on state. Then, the current of the phase with the lower bridge switch on and current sensing resistor is sampled. Then, the current of the other phase is sampled when the voltage space vector is zero, generating the current sampling table as shown in Table 2.

[0048] Table 2

[0049]

[0050] For example, let's take the sector corresponding to the second current sampling value as sector 3. At zero vector, both the u-phase and v-phase lower bridge switches are on. Therefore, the first current sampling value can be either the u-phase current Iu or the v-phase current Iv. In sector 3, the basic effective vector is 100. The u-phase lower bridge switch is off, while the v-phase and w-phase lower bridge switches are on. Since phase v has a current sensing resistor R2, sampling the v-phase current Iv yields the second current sampling value -Iv. Because the v-phase current is the second current sampling value -Iv, at zero vector, sampling the u-phase current Iu yields the first current sampling value -Iu.

[0051] In this embodiment, the phase current to be sampled is determined based on the sector where the effective vector corresponding to the second current sampling value is located, thereby realizing sampling of both zero vector and effective vector.

[0052] In some embodiments, such as Figure 4 As shown, the first current sample value is sampled during the triangular wave decrementing process, and the second current sample value is sampled during the triangular wave incrementing process.

[0053] In other words, with Figure 4 For example, Figure 4 This is a schematic diagram of sampling in sector 3. During the triangular wave countdown process, and before the PWM timer underflow interrupt, the first current sample value is sampled. During the triangular wave countup process, and before the voltage space vector changes from the first effective vector (100) to the second effective vector (110), the second current sample value is sampled. At this time, sampling is performed according to the sampling order shown in Table 2. Within the same sector, the first current sample value is sampled first, and then the second current sample value is sampled.

[0054] In some embodiments, such as Figure 4 As shown, when the voltage space vector is zero, the sampling of one phase current of the two phase currents detected by the dual-resistance current detection circuit includes: determining the start time of the zero vector, and sampling one phase current of the two phase currents after a first preset time delay.

[0055] Specifically, at the beginning of the zero vector, the three-phase lower bridge switch has just switched, and the three-phase current will fluctuate. Therefore, after a first preset time delay, once the three-phase current has stabilized, the current of one of the two phases is sampled to obtain an accurate first current sample value.

[0056] In an optional implementation, the sampling time of the first current sample value Trig1 is obtained according to formula (1):

[0057] Trig1=Ta–Td (1)

[0058] Where Ta is the turn-on time of the u-phase upper bridge switch, and Td is the first preset time.

[0059] In this embodiment, the current of one phase of the two-phase current is sampled only after a first preset time delay at the start of the zero vector. This avoids current fluctuations caused by switching transistors, improves the accuracy of the first current sample value, and thus improves the accuracy of the three-phase current.

[0060] In some embodiments, such as Figure 4 As shown, sampling the phase current detected by the dual-resistance current detection circuit when the voltage space vector is an effective vector includes: determining the start time of switching from the zero vector to the effective vector, and sampling the phase current detected by the dual-resistance current detection circuit after a first preset time delay.

[0061] In other words, when switching from zero vector to effective vector, the switching of the switching transistor causes current fluctuations. Therefore, it is also necessary to wait for a first preset time and after the three-phase current stabilizes before sampling one of the two-phase currents to obtain an accurate second current sampling value.

[0062] In an optional implementation, the sampling time of the second current sample value Trig2 is obtained according to formula (2):

[0063] Trig2=Ta+Td (2)

[0064] Where Ta is the turn-on time of the u-phase upper bridge switch, and Td is the first preset time.

[0065] In some embodiments, such as Figure 5 As shown, both the first and second current sampling values ​​are sampled during the triangular wave count process.

[0066] In other words, during the triangular wave countdown process, and before the voltage space vector changes from the basic effective vector to other vectors, the second current sample value is sampled; during the triangular wave countdown process, and before the PWM timer underflow interrupt, the first current sample value is sampled. Sampling is performed according to the sampling order shown in Table 3. Within the same sector, the second current sample value is sampled first, followed by the first current sample value.

[0067] Table 3

[0068]

[0069] In some embodiments, such as Figure 5 As shown, sampling the phase current detected by the dual-resistance current detection circuit when the voltage space vector is an effective vector includes: determining the start time of switching to the effective vector of the current sector, and sampling the phase current detected by the dual-resistance current detection circuit after a first preset time delay.

[0070] Specifically, Figure 5 This is a schematic diagram of sampling in sector 3. Figure 5 For example, at the beginning of the effective vector, the three-phase lower bridge switch has just switched, and the three-phase current will fluctuate. Therefore, it is necessary to delay for a first preset time and wait for the three-phase current to stabilize before sampling one of the two-phase currents to obtain an accurate second current sampling value.

[0071] In an alternative implementation, the sampling time of the second current sample value Trig2 can be obtained according to formula (3):

[0072] Trig2=Tb–Td (3)

[0073] Where Tb is the turn-off time of the V-phase upper bridge switch, and Td is the first preset time.

[0074] In this embodiment, the current of one phase of the two-phase current is sampled only after a first preset time delay at the start of the effective vector. This avoids current fluctuations caused by switching transistors and improves the accuracy of the second current sample value, thereby improving the accuracy of the three-phase current.

[0075] In some embodiments, such as Figure 5 As shown, when the voltage space vector is zero, sampling one phase current of the two-phase current detected by the dual-resistance current detection circuit includes: determining the start time of switching from the effective vector of the current sector to the zero vector, and sampling one phase current of the two-phase current after a first preset time delay.

[0076] In other words, when switching from the effective vector to the zero vector, the switching of the switching transistor causes current fluctuations. Therefore, it is also necessary to wait for a first preset time and after the three-phase current stabilizes before sampling one of the two-phase currents to obtain an accurate second current sampling value.

[0077] In an alternative implementation, the sampling time of the first current sample value Trig1 can be obtained according to formula (4):

[0078] Trig1=Ta–Td (4)

[0079] Where Ta is the turn-off time of the upper bridge switch of phase u, and Td is the first preset time.

[0080] S102, determine the three-phase current of the motor based on the first current sampling value and the second current sampling value.

[0081] Specifically, the first current sampling value is -Iu, the second current sampling value is -Iv, and the w-phase current Iw is calculated according to formula (5), thus obtaining the three-phase current of the motor:

[0082] I u +I v +I w =0 (5)

[0083] In the above embodiments, by sampling the two-phase current in the dual-resistance current detection circuit at zero vector time and effective vector time respectively, the occupation time of zero vector is reduced and the proportion of effective vector is increased, thereby improving voltage utilization.

[0084] The technical solution of this application will be further described in detail below with reference to specific implementation methods:

[0085] According to Table 2, taking the sampling of the first current sample value during the triangular wave decrementing process and the sampling of the second current sample value during the triangular wave incrementing process as an example, the three-phase current sampling of the motor includes the following steps:

[0086] S201, such as Figure 4 As shown, starting from sector 3, based on the sampling time Trig1 of the first current sample value and the sampling time Trig2 of the second current sample value, before the PWM timer underflow interrupt and at the sampling time Trig1 of the first current sample value, the u-phase current Iu is sampled to obtain the first current sample value -Iu; before the turn-on time Tb of the v-phase upper bridge switch and at the sampling time Trig2 of the second current sample value, the v-phase current Iv is sampled to obtain the second current sample value -Iv.

[0087] S202, in sector 1, based on the sampling time Trig1 of the first current sample value and the sampling time Trig2 of the second current sample value, before the PWM timer underflow interrupt and during the sampling time Trig1 of the first current sample value, the v-phase current Iv is sampled to obtain the first current sample value -Iv; before the turn-on time Ta of the u-phase upper bridge switch and during the sampling time Trig2 of the second current sample value, the u-phase current Iu is sampled to obtain the second current sample value -Iu.

[0088] S203, in sector 5, based on the calculated sampling time Trig1 of the first current sample value and the sampling time Trig2 of the second current sample value, before the PWM timer underflow interrupt and during the sampling time Trig1 of the first current sample value, the v-phase current Iv is sampled to obtain the first current sample value -Iv; before the turn-on time Tc of the w-phase upper bridge switch and during the sampling time Trig2 of the second current sample value, the u-phase current Iu is sampled to obtain the second current sample value -Iu.

[0089] S204, in sector 4, based on the calculated sampling time Trig1 of the first current sample value and the sampling time Trig2 of the second current sample value, before the PWM timer underflow interrupt and during the sampling time Trig1 of the first current sample value, the v-phase current Iv is sampled to obtain the first current sample value -Iv; before the turn-on time Tb of the v-phase upper bridge switch and during the sampling time Trig2 of the second current sample value, the u-phase current Iu is sampled to obtain the second current sample value -Iu.

[0090] S205, in sector 6, based on the calculated sampling time Trig1 of the first current sample value and the sampling time Trig2 of the second current sample value, before the PWM timer underflow interrupt and during the sampling time Trig1 of the first current sample value, the u-phase current Iu is sampled to obtain the first current sample value -Iu; before the turn-on time Ta of the u-phase upper bridge switch and during the sampling time Trig2 of the second current sample value, the v-phase current Iv is sampled to obtain the second current sample value -Iv.

[0091] S206, in sector 2, based on the calculated sampling time Trig1 of the first current sample value and the sampling time Trig2 of the second current sample value, before the PWM timer underflow interrupt and during the sampling time Trig1 of the first current sample value, the u-phase current Iu is sampled to obtain the first current sample value -Iu; before the turn-on time Tc of the w-phase upper bridge switch and during the sampling time Trig2 of the second current sample value, the v-phase current Iv is sampled to obtain the second current sample value -Iv, thus completing all sampling within one PWM cycle.

[0092] S207, the third phase current Iw is calculated based on the first current sampling value and the second current sampling value, thereby obtaining the three-phase currents Iu, Iv, and Iw.

[0093] According to Table 3, taking the sampling of both the first and second current sampling values ​​during the triangular wave counting process as an example, the three-phase current sampling of the motor includes the following steps:

[0094] S301, such as Figure 5 As shown, starting from sector 3, based on the sampling time Trig1 of the calculated first current sample value and the sampling time Trig2 of the second current sample value, after the turn-off time Tb of the upper bridge switch of phase v, and during the sampling time Trig2 of the second current sample value, the sampling of the phase v current Iv is triggered to obtain the second current sample value -Iv; before the underflow interrupt of the PWM timer, and during the sampling time Trig1 of the first current sample value, the sampling of the phase u current Iu is triggered to obtain the first current sample value -Iu.

[0095] S302, in sector 1, based on the sampling time Trig1 of the first current sample value and the sampling time Trig2 of the second current sample value, after the turn-off time Ta of the upper bridge switch of phase u, and during the sampling time Trig2 of the second current sample value, the sampling of the phase u current Iu is triggered to obtain the second current sample value -Iu; before the underflow interrupt of the PWM timer, and during the sampling time Trig1 of the first current sample value, the sampling of the phase v current Iv is triggered to obtain the first current sample value -Iv.

[0096] S303, in sector 5, based on the calculated sampling time Trig1 of the first current sample value and the sampling time Trig2 of the second current sample value, after the turn-off time Tc of the upper bridge switch of phase w, and during the sampling time Trig2 of the second current sample value, the sampling of phase u current Iu is triggered to obtain the second current sample value -Iu; before the PWM timer underflow interrupt, and during the sampling time Trig1 of the first current sample value, the sampling of phase v current Iv is triggered to obtain the first current sample value -Iv.

[0097] S304, in sector 4, based on the calculated sampling time Trig1 of the first current sample value and the sampling time Trig2 of the second current sample value, after the turn-off time Tb of the upper bridge switch of phase v, and during the sampling time Trig2 of the second current sample value, the sampling of the current Iu of phase u is triggered to obtain the second current sample value -Iu; before the underflow interrupt of the PWM timer, and during the sampling time Trig1 of the first current sample value, the sampling of the current Iv of phase v is triggered to obtain the first current sample value -Iv.

[0098] S305, in sector 6, based on the calculated sampling time Trig1 of the first current sample value and the sampling time Trig2 of the second current sample value, after the turn-off time Ta of the upper bridge switch of phase u, and during the sampling time Trig2 of the second current sample value, the sampling of the phase v current Iv is triggered to obtain the second current sample value -Iv; before the underflow interrupt of the PWM timer, and during the sampling time Trig1 of the first current sample value, the sampling of the phase u current Iu is triggered to obtain the first current sample value -Iu.

[0099] S306, in sector 2, based on the calculated sampling time Trig1 of the first current sample value and the sampling time Trig2 of the second current sample value, after the turn-off time Tc of the upper bridge switch of phase w, and during the sampling time Trig2 of the second current sample value, the sampling of the phase v current Iv is triggered to obtain the second current sample value -Iv; before the PWM timer underflow interrupt, and during the sampling time Trig1 of the first current sample value, the sampling of the phase u current Iu is triggered to obtain the first current sample value -Iu.

[0100] S307 calculates the third phase current Iw based on the first current sampling value and the second current sampling value, thereby obtaining the three-phase currents Iu, Iv, and Iw.

[0101] In the above embodiments, in each sector, the two-phase current in the dual-resistance current detection circuit is sampled at zero vector time and effective vector time, respectively. The third-phase current is calculated based on the sampled values ​​of the two-phase current, which reduces the occupation time of the zero vector and increases the proportion of the effective vector, thereby improving the voltage utilization rate.

[0102] In summary, the three-phase current sampling method for a motor according to an embodiment of the present invention samples one phase current in the dual-resistance current detection circuit at zero vector and samples the other phase current in the dual-resistance current detection circuit at effective vector. The three-phase current of the motor is obtained based on the two-phase current sampling values, which reduces the occupation time of zero vector and increases the proportion of effective vector, thereby improving voltage utilization.

[0103] Corresponding to the above embodiments, embodiments of the present invention also provide a computer-readable storage medium storing a three-phase current sampling program for a motor, which, when executed by a processor, implements the three-phase current sampling method for a motor in any of the foregoing embodiments.

[0104] According to the computer-readable storage medium of the present invention, by executing the computer program for sampling the three-phase current of the motor described above, the two-phase current in the dual-resistance current detection circuit is sampled at zero vector time and effective vector time respectively, thereby reducing the zero vector occupation time and increasing the proportion of effective vector, thus improving voltage utilization.

[0105] Corresponding to the above embodiments, embodiments of the present invention also provide a motor controller. For example... Figure 6 As shown, the motor controller 100 includes: a memory 110, a processor 120, and a three-phase current sampling program for the motor stored in the memory 110 and executable on the processor 120. When the processor 120 executes the program, it implements the three-phase current sampling method for the motor in any of the aforementioned embodiments.

[0106] According to the embodiment of the present invention, the motor controller executes a computer program for sampling the three-phase current of the motor through a processor. By sampling the two-phase current in the dual-resistance current detection circuit at zero vector and effective vector respectively, the occupancy time of the zero vector is reduced and the proportion of the effective vector is increased, thereby improving the voltage utilization rate.

[0107] Corresponding to the above embodiments, embodiments of the present invention also provide a three-phase current sampling device for a motor, applied in a motor controller with a dual-resistance current detection circuit. For example... Figure 7 As shown, the three-phase current sampling device for the motor includes a current sampling module 40 and a determination module 50.

[0108] The current sampling module 40 is used to sample one phase current of the two-phase current detected by the dual-resistance current detection circuit when the voltage space vector is zero, to obtain a first current sampling value, and to sample one phase current detected by the dual-resistance current detection circuit when the voltage space vector is an effective vector, to obtain a second current sampling value. The phase of the current sampled when the voltage space vector is zero is different from the phase of the current sampled when the voltage space vector is an effective vector. The determination module 50 is used to determine the three-phase current of the motor based on the first current sampling value and the second current sampling value.

[0109] In some embodiments, the current sampling module 40 is further configured to: determine the sector in which the effective vector corresponding to the second current sampling value is located before sampling one of the two-phase currents detected by the dual-resistance current detection circuit; and determine the one-phase current to be sampled in the two-phase currents based on the sector in which the effective vector corresponding to the second current sampling value is located.

[0110] In some embodiments, the first current sample value is sampled during the triangular wave decrementing process, and the second current sample value is sampled during the triangular wave incrementing process.

[0111] In some embodiments, the current sampling module 40 is further configured to: determine the start time of the zero vector, and sample one of the two phase currents after a first preset time delay.

[0112] In some embodiments, the current sampling module 40 is further configured to: determine the start time of switching from the zero vector to the effective vector, and sample the phase current detected by the dual-resistance current detection circuit after a first preset time delay.

[0113] In some embodiments, both the first current sample value and the second current sample value are sampled during the triangular wave count process.

[0114] In some embodiments, the current sampling module 40 is further configured to: determine the start time of the effective vector switching to the current sector, and sample the phase current detected by the dual-resistance current detection circuit after a first preset time delay.

[0115] In some embodiments, the current sampling module 40 is further configured to: determine the start time of switching from the effective vector to the zero vector of the current sector, and sample one of the two phase currents after a first preset time delay.

[0116] It should be noted that the specific implementation of the three-phase current sampling device for the motor in this embodiment of the invention corresponds one-to-one with the specific implementation of the three-phase current sampling method for the motor in the foregoing embodiments of the invention, and will not be repeated here.

[0117] According to an embodiment of the present invention, a three-phase current sampling device for a motor samples one phase current in a dual-resistance current detection circuit at zero vector and samples the other phase current in a dual-resistance current detection circuit at effective vector. The three-phase current of the motor is obtained based on the two-phase current sampling values, which reduces the zero vector occupation time and increases the proportion of effective vector, thereby improving voltage utilization.

[0118] It should be noted that the logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing 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 (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include: an electrical connection having one or more wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Alternatively, the computer-readable medium may be paper or other suitable media on which the program can be printed, since the program can be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in a computer memory.

[0119] It should be understood that various parts of the present invention can be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0120] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above 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 one or more embodiments or examples.

[0121] Furthermore, the terms "first," "second," etc., used in the embodiments of this invention are for descriptive purposes only and should not be construed as indicating or implying relative importance, or implicitly specifying the number of technical features indicated in this embodiment. Therefore, features defined with terms such as "first" and "second" in the embodiments of this invention can explicitly or implicitly indicate that the embodiment includes at least one of those features. In the description of this invention, the word "multiple" means at least two or more, such as two, three, four, etc., unless otherwise explicitly specified in the embodiments.

[0122] In this invention, unless otherwise explicitly specified or limited in the embodiments, the terms "installation," "connection," "joining," and "fixing" appearing in the embodiments should be interpreted broadly. For example, a connection can be a fixed connection, a detachable connection, or an integral part; it can also be a mechanical connection, an electrical connection, etc. Of course, it can also be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two components, or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific implementation.

[0123] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for sampling three-phase current of a motor, characterized in that, The method, applied in a motor controller with a dual-resistance current detection circuit, includes: When the voltage space vector is zero, one phase current of the two phase currents detected by the dual-resistance current detection circuit is sampled to obtain a first current sampling value. When the voltage space vector is an effective vector, one phase current detected by the dual-resistance current detection circuit is sampled to obtain a second current sampling value. The current phase sampled when the voltage space vector is zero is different from the current phase sampled when the voltage space vector is an effective vector. The three-phase current of the motor is determined based on the first current sampling value and the second current sampling value.

2. The method according to claim 1, characterized in that, Before sampling the first phase current detected by the dual-resistance current detection circuit, the method further includes: Determine the sector where the voltage space vector is an effective vector; Based on the sector where the effective vector is located, determine the phase current that needs to be sampled when the voltage space vector is a zero vector; based on the phase current that needs to be sampled when the voltage space vector is a zero vector, determine the other phase current that needs to be sampled among the two phase currents when the voltage space vector is an effective vector.

3. The method according to claim 1 or 2, characterized in that, The first current sample value is sampled during the triangular wave decrement counting process, and the second current sample value is sampled during the triangular wave increment counting process.

4. The method according to claim 3, characterized in that, When the voltage space vector is zero, sampling is performed on one of the two-phase currents detected by the dual-resistance current detection circuit, including: The start time of the zero vector is determined, and one phase current of the two phase currents is sampled after a first preset time delay.

5. The method according to claim 4, characterized in that, When the voltage space vector is an effective vector, sampling the phase current detected by the dual-resistance current detection circuit includes: Determine the start time for switching from the zero vector to the effective vector, and sample the phase current detected by the dual-resistance current detection circuit after a first preset time delay.

6. The method according to claim 1 or 2, characterized in that, Both the first current sample value and the second current sample value are sampled during the triangular wave count process.

7. The method according to claim 6, characterized in that, When the voltage space vector is an effective vector, sampling the phase current detected by the dual-resistance current detection circuit includes: Determine the start time of switching to the effective vector of the current sector, and sample the phase current detected by the dual-resistance current detection circuit after a first preset time delay.

8. The method according to claim 7, characterized in that, When the voltage space vector is zero, sampling is performed on one of the two-phase currents detected by the dual-resistance current detection circuit, including: Determine the start time of switching from the effective vector of the current sector to the zero vector, and sample one of the two phase currents after a first preset time delay.

9. A computer-readable storage medium, characterized in that, It stores a three-phase current sampling program for the motor, which, when executed by the processor, implements the three-phase current sampling method for the motor according to any one of claims 1-8.

10. A motor controller, characterized in that, include: A memory, a processor, and a three-phase current sampling program for a motor stored in the memory and executable on the processor, wherein when the processor executes the program, it implements the three-phase current sampling method for a motor according to any one of claims 1-8.

11. A three-phase current sampling device for an electric motor, characterized in that, The device, used in a motor controller with a dual-resistance current detection circuit, comprises: The current sampling module is used to sample one phase current of the two-phase current detected by the dual-resistance current detection circuit when the voltage space vector is zero vector to obtain a first current sampling value, and to sample one phase current detected by the dual-resistance current detection circuit when the voltage space vector is a valid vector to obtain a second current sampling value, wherein the current phase sampled when the voltage space vector is zero vector is different from the current phase sampled when the voltage space vector is a valid vector; The determination module is used to determine the three-phase current of the motor based on the first current sampling value and the second current sampling value.

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