Motor and phase current determination method, device, storage medium and program product thereof

Abstract

The present invention discloses a motor and its phase current determination method, device, storage medium, and computer program product. The method comprises: determining a reference voltage vector for the motor based on the motor's operating parameters; inserting a complementary effective voltage vector into the motor's SVPWM modulation based on the motor's reference voltage vector; during the time the inserted complementary effective voltage vector is active, doubly acquiring the DC bus current detected by a single current sensor, recording it as a first current and a second current; and correcting and reconstructing the sampled values ​​of the first-phase current and the second-phase current based on the first and second currents to obtain a sampled value of the motor's third-phase current, thereby determining the motor's phase current. This solution, by inserting the complementary effective voltage vector into the SVPWM modulation and dynamically double-sampling the DC bus current, compensates for errors in the two-phase current sampled values ​​and improves the accuracy of third-phase current reconstruction.

Description

Technical Field

[0001] The present invention belongs to the field of power electronics technology and specifically relates to a method, device, motor, storage medium and computer program product for determining the phase current of a motor, and more particularly to a method, device, motor, storage medium and computer program product for DC bus voltage and current sampling and error compensation with self-correction of zero drift error of a DC bus single current sensor based on complementary effective voltage vectors. Background Art

[0002] In power electronics systems, inverters (such as three-phase two-level inverters) are widely used in motor drive, power conversion and other fields. In order to achieve precise control of the motor, it is necessary to accurately measure the three-phase current output by the inverter. In three-phase two-level inverters, DC bus single current sensors (SCS) are widely used to reconstruct the phase current of the motor. In addition, in the process of reconstructing the phase current, operational amplifiers and voltage reference chips in the inverter hardware circuit are required. However, due to the zero-point drift phenomenon of current sensors, operational amplifiers and voltage reference chips, errors occur in current sampling, and the accuracy of current reconstruction is affected by the error amplification effect.

[0003] The above content is only used to assist in understanding the technical solution of the present invention and does not constitute an admission that the above content is prior art. Summary of the Invention

[0004] The object of the present invention is to provide a method, apparatus, motor, storage medium and computer program product for determining the phase current of a motor, so as to solve the problem that, during the reconstruction process of the phase current of the motor, zero drift in the current sensor, operational amplifier and voltage reference chip causes errors in current sampling, thereby affecting the accuracy of current reconstruction. By inserting complementary effective voltage vectors in SVPWM modulation and dynamically double sampling the DC bus current, the errors of the two-phase current sampling values ​​are compensated, thereby improving the accuracy of the reconstruction of the third-phase current.

[0005] The present invention provides a method for determining the phase current of a motor. The power supply control terminal of the motor has a DC bus. A single current sensor is provided at the DC bus for detecting the current of the DC bus. The method for determining the phase current of the motor comprises: when the motor is running, obtaining operating parameters of the motor and obtaining phase current parameters of the motor. The phase current parameters of the motor include: a sampled value of a first phase current among the three-phase currents of the motor, and a sampled value of a second phase current among the three-phase currents of the motor. A reference voltage vector of the motor is determined based on the operating parameters of the motor. A complementary effective voltage vector is inserted into the SVPWM modulation of the motor based on the reference voltage vector of the motor. During the time when the inserted complementary effective voltage vector acts, the current of the DC bus detected by the single current sensor is obtained twice, recorded as a first current and a second current. Based on the first current and the second current, the sampled values ​​of the first phase current and the sampled values ​​of the second phase current are corrected and reconstructed to obtain a sampled value of the third phase current of the motor, thereby determining the phase current of the motor.

[0006] In some embodiments, based on the reference voltage vector of the motor, a complementary effective voltage vector is inserted in the SVPWM modulation of the motor, including: selecting four effective voltage vectors at the sector position from the basic voltage vector according to the sector position of the reference voltage vector of the motor in the basic voltage vector diagram of the SVPWM modulation; selecting a pair of complementary effective voltage vectors from the four effective voltage vectors, recorded as complementary effective voltage vectors; and inserting the complementary effective voltage vector within the self-calibration area of ​​the reference voltage vector of the motor, so as to determine the time when the inserted complementary effective voltage vector acts as the time of the current observation time window of the motor.

[0007] In some embodiments, within the time when the inserted complementary effective voltage vector acts, the current of the DC bus detected by the single current sensor is obtained twice, and recorded as a first current and a second current, including: obtaining a minimum sampling time determined in advance based on the hardware performance of the motor; within the time when the inserted complementary effective voltage vector acts, the current of the DC bus detected by the single current sensor is obtained twice according to the minimum sampling time, and recorded as the first current and the second current.

[0008] In some embodiments, based on the first current and the second current, the sampling value of the first phase current and the sampling value of the second phase current are corrected and reconstructed to obtain the sampling value of the third phase current of the motor, thereby determining the phase current of the motor, including: based on the first current and the second current, the sampling value of the first phase current and the sampling value of the second phase current are corrected to obtain a first correction current and a second correction current, which are recorded as the correction value of the first phase current of the motor and the correction value of the second phase current of the motor; current is reconstructed according to the correction value of the first phase current of the motor and the correction value of the second phase current of the motor to obtain the sampling value of the third phase current of the motor.

[0009] In some embodiments, based on the first current and the second current, the sampling value of the first phase current and the sampling value of the second phase current are corrected to obtain a first corrected current and a second corrected current, including: taking the sum of the first current and the second current as the zero-point drift; taking the difference between the sampling value of the first phase current and the zero-point drift as the first correction current; and taking the difference between the sampling value of the second phase current and the zero-point drift as the second correction current.

[0010] In some embodiments, current reconstruction is performed based on the correction value of the first phase current of the motor and the correction value of the second phase current of the motor to obtain a sampling value of the third phase current of the motor, including: based on Kirchhoff's current law, determining the relationship between the correction value of the first phase current of the motor, the correction value of the second phase current of the motor, and the sampling value of the third phase current of the motor, and calculating the sampling value of the third phase current of the motor according to the relationship; wherein the calculated sampling value of the third phase current of the motor includes: the average value of the sampling values ​​of the third phase current of the motor calculated more than twice.

[0011] Matching the above method, the present invention provides a phase current determination device for a motor on the other hand, wherein the power supply control end of the motor has a DC bus; a single current sensor is provided at the DC bus for detecting the current of the DC bus; the phase current determination method of the motor comprises: an acquisition unit configured to acquire the operating parameters of the motor and the phase current parameters of the motor when the motor is running; wherein the phase current parameters of the motor include: a sampling value of the first phase current of the three-phase current of the motor, and a sampling value of the second phase current of the three-phase current of the motor; a control unit configured to determine the phase current of the motor according to the operating parameters of the motor. The reference voltage vector of the motor; the control unit is further configured to insert a complementary effective voltage vector in the SVPWM modulation of the motor according to the reference voltage vector of the motor; the acquisition unit is further configured to acquire the current of the DC bus detected by the single current sensor twice within the time when the inserted complementary effective voltage vector acts, and record it as the first current and the second current; the control unit is further configured to correct and reconstruct the sampling value of the first phase current and the sampling value of the second phase current based on the first current and the second current, obtain the sampling value of the third phase current of the motor, and determine the phase current of the motor.

[0012] In some embodiments, the control unit inserts a complementary effective voltage vector in the SVPWM modulation of the motor based on the reference voltage vector of the motor, including: selecting four effective voltage vectors at the sector position from the basic voltage vector based on the sector position of the reference voltage vector of the motor in the basic voltage vector diagram of the SVPWM modulation; selecting a pair of complementary effective voltage vectors from the four effective voltage vectors, recorded as complementary effective voltage vectors; and inserting the complementary effective voltage vector within the self-calibration area of ​​the reference voltage vector of the motor, so as to determine the time when the inserted complementary effective voltage vector acts as the time of the current observation time window of the motor.

[0013] In some embodiments, the acquisition unit acquires the current of the DC bus detected by the single current sensor twice within the time when the inserted complementary effective voltage vector acts, and records them as the first current and the second current, including: acquiring a minimum sampling time determined in advance based on the hardware performance of the motor; and acquiring the current of the DC bus detected by the single current sensor twice according to the minimum sampling time within the time when the inserted complementary effective voltage vector acts, and records them as the first current and the second current.

[0014] In some embodiments, the control unit corrects and reconstructs the sampling value of the first phase current and the sampling value of the second phase current based on the first current and the second current to obtain the sampling value of the third phase current of the motor, thereby determining the phase current of the motor, including: correcting the sampling value of the first phase current and the sampling value of the second phase current based on the first current and the second current to obtain a first correction current and a second correction current, which are recorded as the correction value of the first phase current of the motor and the correction value of the second phase current of the motor; reconstructing the current according to the correction value of the first phase current of the motor and the correction value of the second phase current of the motor to obtain the sampling value of the third phase current of the motor.

[0015] In some embodiments, the control unit corrects the sampling value of the first phase current and the sampling value of the second phase current based on the first current and the second current to obtain a first correction current and a second correction current, including: taking the sum of the first current and the second current as the zero-point drift; taking the difference between the sampling value of the first phase current and the zero-point drift as the first correction current; and taking the difference between the sampling value of the second phase current and the zero-point drift as the second correction current.

[0016] In some embodiments, the control unit performs current reconstruction based on the correction value of the first phase current of the motor and the correction value of the second phase current of the motor to obtain the sampling value of the third phase current of the motor, including: determining the relationship between the correction value of the first phase current of the motor, the correction value of the second phase current of the motor, and the sampling value of the third phase current of the motor based on Kirchhoff's current law, and calculating the sampling value of the third phase current of the motor according to the relationship; wherein, the sampling value of the third phase current of the motor calculated by the control unit includes: the average value of the sampling values ​​of the third phase current of the motor calculated more than twice.

[0017] Matching the above-mentioned device, the present invention further provides a motor, comprising: the above-mentioned motor phase current determination device.

[0018] In accordance with the above method, the present invention further provides a storage medium comprising a stored program, wherein when the program is running, the device where the storage medium is located is controlled to execute the steps of the above-mentioned method for determining the phase current of the motor.

[0019] In accordance with the above method, the present invention further provides a computer program product, comprising a computer program, which implements the steps of the above method for determining the phase current of a motor when executed by a processor.

[0020] Therefore, the solution of the present invention is to sample the three-phase current provided by the power supply control end of the motor (such as the three-phase current output by the motor controller or the inverter in the frequency converter), and determine the reference voltage vector of the motor (such as the reference voltage vector Vref) according to the operating parameters of the motor when the motor is running; select a pair of complementary effective voltage vectors from the corresponding basic voltage vectors according to the sector position of the reference voltage vector of the motor (that is, the position of the reference voltage vector Vref in the basic voltage vector diagram of SVPWM); insert the complementary effective voltage vector in the self-calibration area of ​​the reference voltage vector of the motor instead of the zero vector in the SVPWM modulation method; , determine the time of the current observation window (that is, the duration of the current observation window is greater than the minimum sampling time Tmin); within the current observation window, use the DC bus single current sensor to dynamically double-sample the DC bus current according to the minimum sampling time to obtain two sampled currents; correct the two sampled currents to obtain two-phase currents; reconstruct the third-phase current based on the two-phase currents to determine the three-phase current of the motor; thus, by inserting complementary effective voltage vectors in SVPWM modulation and dynamically double-sampling the DC bus current, error compensation of the two-phase current sampling values ​​is achieved, thereby improving the accuracy of reconstruction of the third-phase current.

[0021] Other features and advantages of the present invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the present invention.

[0022] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 1 is a flow chart of an embodiment of a method for determining a phase current of a motor according to the present invention;

[0024] Figure 2 1. A flow chart of an embodiment of a method for inserting a complementary effective voltage vector in the present invention;

[0025] Figure 3 1. A schematic flow chart of an embodiment of the method of the present invention for obtaining the current of the DC bus detected by the single current sensor twice;

[0026] Figure 4 A flowchart of an embodiment of the method of the present invention for correcting and reconstructing the sampled values ​​of the first phase current and the second phase current based on the first current and the second current to obtain the sampled value of the third phase current of the motor;

[0027] Figure 51. A flow chart of an embodiment of the method of the present invention for correcting the sampled value of the first phase current and the sampled value of the second phase current based on the first current and the second current;

[0028] Figure 6 Schematic diagram of the structure of an embodiment of a device for determining phase current of a motor according to the present invention;

[0029] Figure 7 It is a structural diagram of a three-phase bridge inverter circuit;

[0030] Figure 8 It is a schematic diagram of the basic voltage vector synthesis modulation area;

[0031] Figure 9 Schematic diagram for inserting complementary effective voltage vectors;

[0032] Figure 10 The present invention is a flow chart of a DC bus voltage and current sampling and error compensation method based on self-correction of zero drift error of a DC bus single current sensor using complementary effective voltage vector.

[0033] In conjunction with the accompanying drawings, the reference numerals in the embodiments of the present invention are as follows:

[0034] 102 - acquisition unit; 104 - control unit. DETAILED DESCRIPTION

[0035] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments of the present invention and corresponding drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0036] Considering that during the motor phase current reconstruction process, zero-point drift in the current sensor, operational amplifier, and voltage reference chip causes current sampling errors, which in turn affects the accuracy of current reconstruction. While the use of multiple current sensors in related solutions can improve accuracy, it also increases system complexity and cost.

[0037] Some solutions use a three-resistor current sampling method for inverters based on current prediction. During each pulse width modulation (PWM) cycle, the three-phase PWM comparison values ​​T1, T2, and T3 are obtained through current closed-loop PID (proportional-integral-differential) control and space vector pulse width modulation (SVGEN) modulation. These values ​​are then compared in real time with the minimum time Tmin required for complete sampling. Different current acquisition methods are used based on the relationship between these values. This solves the problem of insufficient zero voltage vector duration at high modulation ratios in traditional three-resistor sampling technology for three-phase inverters, which results in an inability to accurately sample three-phase currents. This method enables wide-range current closed-loop control under three-resistor sampling, improves the modulation ratio, and increases motor load capacity. It is low-cost, simple, and reliable. While this solution solves the problem of insufficient zero voltage vector duration at high modulation ratios in three-resistor sampling technology, it requires multiple resistors, increasing hardware cost and complexity.

[0038] Some solutions also offer a novel hybrid space vector pulse width modulation (SVPWM) method for optimizing torque ripple in permanent magnet synchronous motors (PMSMs) powered by four-switch inverters. This method alternates between two different modulation schemes in different sectors, introduces a novel method for deriving the effective value of torque ripple, and makes sector division independent of motor parameters. A novel sector division method is also proposed, simplifying sector division. This novel hybrid SVPWM method improves upon the existing modulation scheme, effectively reducing the computational workload of digital signal processors (DSPs), offering engineering value. It also effectively reduces PMSM torque ripple when motor parameters vary. While the aforementioned patent proposes a new sector division method, the introduction of two different modulation schemes may increase system complexity, particularly in software implementation and hardware design. This can extend development cycles and increase costs. The use of two different modulation schemes can also make system debugging more difficult. In practical applications, ensuring smooth switching between the two modulation schemes is crucial to avoid performance degradation or instability. However, the introduction of two different modulation methods increases the complexity of the system, which may lead to an extension of the development cycle and an increase in costs, as well as increased difficulty in system debugging.

[0039] Other proposals propose a three-level inverter indirect vector control system based on simplified SVPWM. This approach utilizes a simplified SVPWM algorithm in a 60° coordinate system to simplify the vector control process, reduce trigonometric calculations and sector determination, and improve real-time control capabilities. This patent requires replacing the traditional orthogonal coordinate system with a non-orthogonal 60° coordinate system for the basic hexagonal vector diagram of the three-level inverter, and normalizing the basic space vector diagram. Using a 60° coordinate system instead of a traditional orthogonal coordinate system may result in a decrease in vector control accuracy. While simplifying the calculation process, it may not accurately represent all operating conditions, particularly when the reference voltage is in an unobservable region, such as overmodulation. This patent addresses the inaccurate sampling problem of traditional SVPWM methods in unobservable regions by inserting complementary effective voltage vectors in place of the zero vector. The use of complementary effective voltage vectors ensures that the current observation window duration is greater than the minimum sampling time, improving current sampling accuracy. However, using a 60° coordinate system instead of a traditional orthogonal coordinate system may result in a decrease in vector control accuracy, particularly when the reference voltage is in an unobservable region, such as overmodulation.

[0040] While the use of multiple current sensors in related solutions can improve measurement accuracy, it also increases system complexity and cost. Consequently, single current sensor (SCS) phase current reconstruction has become a research hotspot. However, the zero-point drift of SCSs can lead to current sampling errors, which in turn affects the accuracy of phase current reconstruction.

[0041] Therefore, an effective self-correction strategy is needed to solve the above problems. Therefore, the solution of the present invention proposes a method for determining the phase current of a motor, specifically a DC bus voltage and current sampling and error compensation method based on the self-correction of the zero-drift error of a DC bus single current sensor using a complementary effective voltage vector. The self-correction strategy for the zero-drift error of a DC bus single current sensor is adopted, especially for the self-correction strategy for the zero-drift error of a DC bus single current sensor in a three-phase two-level inverter. By inserting the complementary effective voltage vector and the dynamic current dual current sampling technology, the self-detection and self-correction of the current zero-drift amount are achieved, thereby improving the accuracy of phase current reconstruction.

[0042] According to an embodiment of the present invention, a method for determining the phase current of a motor is provided. Figure 1 The flow chart of an embodiment of the method of the present invention is shown in FIG. The power supply control end of the motor (such as a frequency converter or a motor controller) has a DC bus; a single current sensor is provided at the DC bus for detecting the current of the DC bus. Figure 7 It is a structural diagram of a three-phase bridge inverter circuit. Figure 7As shown, a three-phase bridge inverter circuit is provided between the DC bus and the motor (PMSM). The three-phase bridge inverter circuit includes switches M1, M2, M3, M4, M5, and M6. Each switch can be an insulated gate bipolar transistor (IGBT), with the gate of the IGBT serving as the control terminal, the collector of the IGBT serving as the first connection terminal, and the emitter of the IGBT serving as the second connection terminal. The positive end of the bus voltage V of the DC bus is connected to the first connection end of the switch tube M1, the first connection end of the switch tube M2, and the first connection end of the switch tube M3, respectively; the negative end of the bus voltage V of the DC bus is connected to the second connection end of the switch tube M4, the second connection end of the switch tube M5, and the second connection end of the switch tube M6, respectively; the second connection end of the switch tube M1 is connected to the first connection end of the switch tube M4, the second connection end of the switch tube M2 is connected to the first connection end of the switch tube M5, and the second connection end of the switch tube M3 is connected to the first connection end of the switch tube M6. The switch tube M1 and the switch tube M4 constitute the first phase bridge arm of the three-phase bridge arm, and the common end of the switch tube M1 and the switch tube M4 is connected to the first phase winding of the three-phase winding of the motor; the switch tube M2 and the switch tube M5 constitute the second phase bridge arm of the three-phase bridge arm, and the common end of the switch tube M2 and the switch tube M5 is connected to the second phase winding of the three-phase winding of the motor; the switch tube M3 and the switch tube M6 constitute the third phase bridge arm of the three-phase bridge arm, and the common end of the switch tube M3 and the switch tube M6 is connected to the third phase winding of the three-phase winding of the motor.

[0043] In the solution of the present invention, Figure 1 As shown, the method for determining the phase current of the motor includes: steps S110 to S150.

[0044] At step S110, when the motor is running, operating parameters of the motor and phase current parameters of the motor are obtained; wherein the phase current parameters of the motor include: a sampled value of a first phase current among the three-phase currents of the motor, and a sampled value of a second phase current among the three-phase currents of the motor. The phase current parameters of the motor can be sampled from the output end of the power supply control end of the motor (such as the output end of the inverter in the frequency converter or motor controller).

[0045] In step S120 , a reference voltage vector of the motor is determined according to the operating parameters of the motor. Figure 10 The figure is a flow chart of DC bus voltage and current sampling and error compensation based on the self-correction of zero drift error of DC bus single current sensor with complementary effective voltage vector. Figure 10 As shown, the voltage and current sampling and error compensation method of the DC bus includes:

[0046] Step 1: Calculate the reference voltage vector Vref according to the operating state of the motor, and then execute step 2.

[0047] In step 1, the reference voltage vector Vref is calculated according to the operating state of the motor, which specifically includes:

[0048] Step 11: Acquire the operating parameters of the motor. The acquired operating parameters of the motor include the motor speed, load current, temperature, etc., and then execute step 12.

[0049] During motor operation, load current refers to the actual current drawn from the power supply when the motor is driving a load. This current reflects the motor's actual operating intensity, or the work performed to overcome the load's resistance. The load current varies with the load. As the load increases, the motor requires greater torque to drive the load, increasing the load current. Conversely, as the load decreases, the load current decreases. Phase current: For a three-phase AC motor, phase current refers to the current flowing through each phase winding. In a balanced three-phase system, the three-phase currents are equal in magnitude and 120 degrees out of phase with each other. Phase current is primarily used to analyze the motor's internal operating state, such as determining whether the motor is operating normally or if a fault exists.

[0050] Step 12: Determine a control target, such as maintaining stable operation of the motor, optimizing efficiency, etc., and then execute step 13.

[0051] Step 13: Calculate the reference voltage vector Vref: Calculate the required reference voltage vector Vref based on the motor's mathematical model and control objectives. For example, the reference voltage vector Vref can be calculated using a vector control algorithm based on the voltage equation, flux equation, and torque equation in the motor's mathematical model.

[0052] At step S130 , a complementary effective voltage vector is inserted into the SVPWM modulation of the motor according to the reference voltage vector of the motor.

[0053] In step S140 , within the time period when the inserted complementary effective voltage vector acts, the current of the DC bus detected by the single current sensor is acquired twice, and recorded as a first current and a second current.

[0054] At step S150, based on the first current and the second current, the sampling value of the first phase current and the sampling value of the second phase current are corrected and reconstructed to obtain the sampling value of the third phase current of the motor, thereby determining the phase current of the motor.

[0055] The present invention proposes a DC bus voltage and current sampling and error compensation scheme that self-corrects zero-drift errors in a single DC bus current sensor based on complementary effective voltage vectors. By incorporating complementary effective voltage vectors and dynamic current dual sampling technology, this scheme achieves self-detection and self-correction of current zero-drift, improving the accuracy of phase current reconstruction. This scheme improves the accuracy of third-phase current reconstruction and reduces the impact of error amplification effects, while maintaining system simplicity and cost-effectiveness. It demonstrates excellent performance across various modulation regions and operating conditions, meeting the performance requirements of motor control systems.

[0056] In some embodiments, the specific process of inserting the complementary effective voltage vector in the SVPWM modulation of the motor according to the reference voltage vector of the motor in step S130 is described in the following exemplary embodiments.

[0057] The following combination Figure 2 FIG2 is a flow chart of an embodiment of the method for inserting a complementary effective voltage vector in the present invention, further illustrating the specific process of inserting a complementary effective voltage vector in step S130 , including steps S210 to S230 .

[0058] Step S210 , according to the sector position of the motor's reference voltage vector in the basic voltage vector diagram of SVPWM modulation, four effective voltage vectors at the sector position are selected from the basic voltage vectors.

[0059] In step S220 , a pair of complementary effective voltage vectors are selected from the four effective voltage vectors and recorded as complementary effective voltage vectors.

[0060] Step S230 : inserting the complementary effective voltage vector into the self-calibration region of the reference voltage vector of the motor, and determining the time when the inserted complementary effective voltage vector acts as the time of the current observation time window of the motor.

[0061] Figure 8 Figure 2 is a schematic diagram of the basic voltage vector synthesis modulation area. The inverter is controlled using space vector pulse width modulation (SVPWM) technology. By linearly combining the basic voltage space vectors, the stator flux inside the motor forms a vector circle, thus ensuring stable electromagnetic torque output by the motor. Figure 8 In the figure, the self-calibration area includes: low modulation area, overmodulation area and sector boundary; the sectors include: sector I, sector II, sector III, sector IV, sector V, sector VI; the unobservable area includes: the area within the dotted line; the basic voltage vectors include: vector V0, vector V1, vector V2, vector V3, vector V4, vector V5, vector V6, vector V7, and vector V0 and vector V7 are located in the center circle ( Figure 8 not shown).

[0062] like Figure 8 As shown, corresponding to the switching states of the upper bridge arm (000, 001, 010, 011, 100, 101, 110, 111), the motor has eight basic voltage space vectors: V0, V1, V2, V3, V4, V5, V6, and V7. For the upper bridge arm switching state 000, the motor's basic voltage space vector is V0; for the upper bridge arm switching state 001, the motor's basic voltage space vector is V1; for the upper bridge arm switching state 010, the motor's basic voltage space vector is V2; for the upper bridge arm switching state 011, the motor's basic voltage space vector is V3; for the upper bridge arm switching state 100, the motor's basic voltage space vector is V4; for the upper bridge arm switching state 101, the motor's basic voltage space vector is V5; for the upper bridge arm switching state 110, the motor's basic voltage space vector is V6; and for the upper bridge arm switching state 111, the motor's basic voltage space vector is V7. Among them, V1, V2, V3, V4, V5, V6 are valid vectors, V0 and V7 are zero vectors, corresponding to Figure 8 The most central circle area (in Figure 8 The reference voltage vector Vref can be mapped to Figure 8 In the figure, Vref takes the center as the origin, starts from V1, and rotates counterclockwise. The rotation trajectory is Figure 8 For the circle in the figure, the Vref amplitude will not exceed the radius of the circle.

[0063] Figure 9 Schematic diagram for inserting complementary effective voltage vectors. Figure 9 In , the solid line is the basic voltage vector, the dotted line is the sector boundary, and the red line is the component that decomposes the reference voltage into the basic voltage vector. Figure 9 In the figure, Vref is decomposed and synthesized by the basic voltage vectors in the figure; that is, the reference voltage vector Vref obtained by the volt-second balance theory can be synthesized by 4 basic voltage vectors, namely:

[0064] Vref(cosθ+jsinθ)Ts=V1T1+V2T2+V3T0 / 2+V6T0 / 2.

[0065] Where θ represents the rotation angle of Vref in the space vector plane, Ts represents the carrier period of the modulation system, T1 represents the duration of the V1 voltage vector, T2 represents the duration of the V2 voltage vector, and T0 represents the duration of the voltage vectors V3 and V6.

[0066] See also Figure 7 、 Figure 8 and Figure 9In the example shown, Vd and Vq are calculated by the motor control algorithm, and Vref is calculated. Vref has magnitude and direction. According to the magnitude and direction of Vref, it is determined whether Vref is Figure 8 Which sector is it in? If it is in sector I, then Figure 9 As shown, Vref is decomposed into the basic voltage vector Vref(cosθ+jsinθ)Ts=V1T1+V2T2+V3T0 / 2+V6T0 / 2. Among them, V1, V2, V3, V6 are actually Figure 7 The switching state of the upper arm of the three-phase inverter circuit indicates that the upper arm is turned on. T1, T2, T3, and T6 are the on-times. Thus, software algorithms control the hardware circuits, enabling the generation and control of reference voltages and further controlling the motor's operation.

[0067] In the SVPWM modulation method, the basic voltage vector action time of each sector determines the duration of the current observation window. In order to ensure accurate current sampling, it is necessary to analyze the duration of the current observation window of each sector. Specifically, Figure 8 and Figure 9 As shown, when the reference voltage vector Vref is located in an unobservable area (ie, a sector boundary or an overmodulation area), the action time of the effective voltage vector may be less than the minimum sampling time Tmin, resulting in an inability to accurately collect the current.

[0068] To extend the current observation window, the present invention proposes inserting complementary effective voltage vectors into the SVPWM modulation method, replacing the zero vector used in related schemes. The present invention addresses the inaccurate sampling problem of the SVPWM method in unobservable regions in related schemes by inserting complementary effective voltage vectors in place of the zero vector. The use of complementary effective voltage vectors ensures that the current observation window is longer than the minimum sampling time, improving current sampling accuracy.

[0069] like Figure 10 As shown, the DC bus voltage and current sampling and error compensation method also includes:

[0070] Step 2: Select a suitable basic voltage vector according to the position of the reference voltage vector Vref, and then execute step 3.

[0071] In step 2, according to the position of the reference voltage vector Vref, a suitable basic voltage vector is selected, which specifically includes:

[0072] Step 21, determine the position of the reference voltage vector Vref, and then execute step 22. In step 21, specifically, the reference voltage vector Vref is projected onto the basic voltage vector diagram of SVPWM, such as Figure 8As shown, determine the sector where the reference voltage vector Vref is located. When the reference voltage vector Vref is in the first sector, the projection of Vref is as follows: Figure 9 shown.

[0073] Step 22, select the basic voltage vector: select a suitable basic voltage vector according to the position of the reference voltage vector Vref in the basic voltage vector diagram of SVPWM, and then execute step 23.

[0074] like Figure 8 As shown, the basic voltage vector diagram of SVPWM is divided into six sectors, each sector corresponding to a set of basic voltage vectors. For example, if the reference voltage vector Vref is located in the first sector (i.e., sector I), vector V6, vector V1, vector V2, and vector V3 are selected as the basic voltage vectors. If the reference voltage vector Vref is located in the second sector (i.e., sector II), vector V1, vector V2, vector V3, and vector V4 are selected as the basic voltage vectors. If the reference voltage vector Vref is located in the third sector (i.e., sector III), vector V2, vector V3, vector V4, and vector V5 are selected as the basic voltage vectors. If the reference voltage vector Vref is located in the fourth sector (i.e., sector IV), vector V3, vector V4, vector V5, and vector V6 are selected as the basic voltage vectors. If the reference voltage vector Vref is located in the fifth sector (i.e., sector V), vector V4, vector V5, vector V6, and vector V1 are selected as the basic voltage vectors. If the reference voltage vector Vref is located in the sixth sector (ie, sector VI), vector V5, vector V6, vector V1, and vector V2 are selected as basic voltage vectors.

[0075] Step 23, calculating the action time: calculating the action time of each basic voltage vector in the selected basic voltage vectors according to the position of the reference voltage vector Vref and the modulation algorithm of SVPWM.

[0076] Step 3: Insert the complementary effective voltage vector in the selected basic voltage vector into the self-correction region of the reference voltage vector Vref, and then execute step 4.

[0077] In step 3, two adjacent effective voltage vectors (i.e., complementary effective voltage vectors) are used to replace the sporadic vectors (i.e., vector V0 and vector V7) to ensure that the duration of the current observation window is greater than the minimum sampling time Tmin. The duration of the current observation window is as follows: Figure 8 The time Ts is shown.

[0078] In step 3, a complementary effective voltage vector of the selected basic voltage vector is inserted into the self-correction region of the reference voltage vector Vref, specifically including:

[0079] Step 31: Determine the self-correction region of the reference voltage vector Vref, and then proceed to step 32. Figure 8 As shown in the figure, the self-correction region of the reference voltage vector Vref includes: the undermodulation region, the overmodulation region, and the sector boundary. During the SVPWM modulation process, when the reference voltage vector Vref is located in an unobservable region (such as a sector boundary or overmodulation region), the zero vector action time in the relevant scheme may be less than the minimum sampling time Tmin. Therefore, it is necessary to use two adjacent effective voltage vectors (i.e., complementary effective voltage vectors) to replace the zero vectors (i.e., vectors V0 and V7) to ensure that the duration of the current observation window is greater than the minimum sampling time Tmin.

[0080] Step 32: Select a complementary effective voltage vector in the self-correction region of the reference voltage vector Vref, and then execute step 33. In step 32, in the self-correction region of the reference voltage vector Vref, select two adjacent effective voltage vectors to replace the zero vector (ie, vector V0 and vector V7).

[0081] For example, if the self-correction region of the reference voltage vector Vref is in the first sector (i.e., sector I), then the complementary effective voltage vectors such as vector V6 and vector V3 from among the basic voltage vectors such as vector V6, vector V1, vector V2, and vector V3 are selected. If the self-correction region of the reference voltage vector Vref is in the second sector (i.e., sector II), then the complementary effective voltage vectors such as vector V1 and vector V4 from among the basic voltage vectors such as vector V1, vector V2, vector V3, and vector V4 are selected. If the self-correction region of the reference voltage vector Vref is in the third sector (i.e., sector III), then the complementary effective voltage vectors such as vector V2 and vector V5 from among the basic voltage vectors such as vector V2, vector V3, vector V4, and vector V5 are selected. If the self-correction region of the reference voltage vector Vref is in the fourth sector (i.e., sector IV), then the complementary effective voltage vectors such as vector V3 and vector V6 from among the basic voltage vectors such as vector V3, vector V4, vector V5, and vector V6 are selected. If the self-correction region of the reference voltage vector Vref is in the fifth sector (i.e., sector V), then complementary effective voltage vectors such as vectors V4 and V1 are selected from among the basic voltage vectors such as vectors V4, V5, V6, and V1. If the self-correction region of the reference voltage vector Vref is in the sixth sector (i.e., sector VI), then complementary effective voltage vectors such as vectors V5 and V2 are selected from among the basic voltage vectors such as vectors V5, V6, V1, and V2.

[0082] Step 33: Allocate the action time: divide the action time T0 of the zero vector equally between the two complementary effective voltage vectors. For example, if the self-correction region of the reference voltage vector Vref is in the first sector (i.e., sector I), then select the complementary effective voltage vectors such as vector V6 and vector V3 from the basic voltage vectors such as vector V6, vector V1, vector V2, and vector V3, and divide the action time T0 of the zero vector equally between the two complementary effective voltage vectors such as vector V6 and vector V3, as follows:

[0083] V0*T0=V3*T0 / 2+V6*T0 / 2 (2).

[0084] In the solution of the present invention, by inserting a complementary effective voltage vector from the selected basic voltage vector within the self-correction region of the reference voltage vector Vref, the action time T0 of the zero vector can be equally divided into two complementary effective voltage vectors such as vector V6 and vector V3, thereby ensuring that the duration of the current observation window is greater than the minimum sampling time Tmin, thereby improving the accuracy of current sampling.

[0085] Specifically, taking sector I as an example, within the self-correction region of the reference voltage vector Vref, the zero vectors V0 and V7 in the SVPWM switching sequence in the relevant scheme are replaced by two adjacent effective voltage vectors V3 and V6, as shown in Figure 8 As shown in Figure 2, the action time T0 of the zero vector is divided equally into two complementary effective voltage vectors, which is formula (2).

[0086] In different sectors, the switching sequence for inserting complementary effective voltage vectors is shown in Table 1:

[0087] Table 1

[0088] sector Effective vector Switching sequence Ⅰ V1,V2,V3,V6 V6,V1,V2,V3-V3,V2,V1,V6 Ⅱ V1,V2,V3,V4 V4,V3,V2,V1-V1,V2,V3,V4 Ⅲ V2,V3,V4,V5 V2,V3,V4,V5-V5,V4,V3,V2 Ⅳ V3,V4,V5,V6 V6,V5,V4,V3-V3,V4,V5,V6 Ⅴ V1,V4,V5,V6 V5,V4,V6,V1-V1,V6,V4,V5 Ⅵ V1,V2,V5,V6 V2,V1,V6,V5-V5,V6,V1,V2

[0089] For example, in Table 1, the switching sequence is V6, V1, V2, V3-V3, V2, V1, V6, which means that the switch status changes from V6, V1, V2, V3 to V3, V2, V1, V6.

[0090] In some embodiments, in step S140, within the time period when the inserted complementary effective voltage vector is applied, the current of the DC bus detected by the single current sensor is obtained twice, and the current is recorded as the first current and the second current. For a specific process, see the following exemplary description.

[0091] The following combination Figure 3The flowchart of an embodiment of the method of the present invention for obtaining the current of the DC bus detected by the single current sensor twice is shown, which further illustrates the specific process of obtaining the current of the DC bus detected by the single current sensor twice in step S140, including: steps S310 to S320.

[0092] Step S310: obtaining a minimum sampling time predetermined according to the hardware performance of the motor.

[0093] Step S320: During the time period when the inserted complementary effective voltage vector is in effect, the current of the DC bus detected by the single current sensor is acquired twice at the minimum sampling time, and these currents are recorded as a first current and a second current. That is, during the current observation time window of the motor, the current of the DC bus sampled twice by the single current sensor is acquired at the predetermined minimum sampling time, and these currents are recorded as the first current and the second current. For example, during the time period when the inserted complementary effective voltage vector is in effect, the current of the DC bus detected by the single current sensor at the minimum sampling time is acquired for the first time, and this current is recorded as the first current; and, still during the time period when the inserted complementary effective voltage vector is in effect, the current of the DC bus detected by the single current sensor at the minimum sampling time is acquired for the second time, and this current is recorded as the second current. The sum of the sampling times of the first current and the second current is less than the time period when the inserted complementary effective voltage vector is in effect.

[0094] like Figure 10 As shown, the DC bus voltage and current sampling and error compensation method also includes: step 4, after inserting the complementary effective voltage vector in the selected basic voltage vector within the self-correction area of ​​the reference voltage vector Vref, double sampling of the DC bus current based on the inserted complementary voltage vector to obtain sampled currents I1 and I2, and then executing step 5.

[0095] In step 4, the DC bus current is double sampled based on the inserted complementary voltage vector to obtain the sampled currents I1 and I2. The specific sampling method is as follows:

[0096] Step 41, calculate the minimum sampling time Tmin: Calculate the minimum sampling time Tmin based on the performance of the hardware device, and then execute step 42. For example, based on the performance of the hardware device, the minimum sampling time Tmin of the current sampling AD conversion chip used is 12ns.

[0097] Step 42 , performing double current sampling on the DC bus current: within the inserted complementary voltage vector action time (such as time Ts), using a single current sensor, based on the minimum sampling time Tmin, perform two samplings on the DC bus current to obtain sampling currents I1 and I2.

[0098] In the solution of the present invention, the dynamic current double current sampling technology is used to achieve self-detection and self-correction of the current zero drift, thereby improving the accuracy of the third-phase current reconstruction.

[0099] In some embodiments, in step S150, based on the first current and the second current, the sampling value of the first phase current and the sampling value of the second phase current are corrected and reconstructed to obtain the sampling value of the third phase current of the motor, thereby realizing the specific process of determining the phase current of the motor. Please refer to the following exemplary description.

[0100] The following combination Figure 4 The method of the present invention is shown as a flow chart of an embodiment of correcting and reconstructing the sampling value of the first phase current and the sampling value of the second phase current based on the first current and the second current to obtain the sampling value of the third phase current of the motor, further illustrating the specific process of correcting and reconstructing the sampling value of the first phase current and the sampling value of the second phase current based on the first current and the second current in step S150 to obtain the sampling value of the third phase current of the motor, including: steps S410 to S420.

[0101] Step S410: Based on the first current and the second current, the sampling value of the first phase current and the sampling value of the second phase current are corrected to obtain a first corrected current and a second corrected current, which are recorded as the corrected value of the first phase current of the motor and the corrected value of the second phase current of the motor.

[0102] Step S420 , performing current reconstruction according to the correction value of the first phase current of the motor and the correction value of the second phase current of the motor to obtain a sampling value of the third phase current of the motor.

[0103] In the solution of the present invention, an error self-correction strategy is proposed by analyzing the duration of the current observation window of each sector, which can effectively reduce the impact of zero point drift on phase current reconstruction under different modulation areas and working conditions.

[0104] In some embodiments, in step S410, the sampling value of the first phase current and the sampling value of the second phase current are corrected based on the first current and the second current to obtain a first corrected current and a second corrected current, which are recorded as the corrected value of the first phase current of the motor and the corrected value of the second phase current of the motor. For the specific process, please refer to the following exemplary description.

[0105] The following combination Figure 5The method of the present invention is shown as a flow chart of an embodiment of correcting the sampling value of the first phase current and the sampling value of the second phase current based on the first current and the second current, further illustrating the specific process of correcting the sampling value of the first phase current and the sampling value of the second phase current based on the first current and the second current in step S410, including: steps S510 to S520.

[0106] Step S510: taking the sum of the first current and the second current as the zero drift.

[0107] Step S520 , using the difference between the sampled value of the first phase current and the zero drift as a first correction current; and using the difference between the sampled value of the second phase current and the zero drift as a second correction current.

[0108] like Figure 10 As shown, the DC bus voltage and current sampling and error compensation method further includes: step 5, correcting the sampled currents I1 and I2 to perform error compensation, and then executing step 6.

[0109] In step 5, the sampled currents I1 and I2 are calibrated, specifically including:

[0110] Step 51 , calculating the zero-point drift Ie: calculating the zero-point drift Ie according to the sampled current: 2Ie=I1+I2, and then executing step 52.

[0111] Step 52 , correcting the sampling current: correcting the sampling current using the zero-point drift Ie to obtain corrected phase currents Ic1 and Ic2 .

[0112] In the solution of the present invention, dynamic current dual current sampling: using complementary effective voltage vector dynamic current dual current sampling, self-detection and self-correction of current zero drift are realized, and the impact of zero drift on current reconstruction accuracy is effectively reduced without adding additional hardware equipment.

[0113] In some embodiments, in step S420, current reconstruction is performed based on the correction value of the first phase current of the motor and the correction value of the second phase current of the motor to obtain the sampling value of the third phase current of the motor, including: based on Kirchhoff's current law, determining the relationship between the correction value of the first phase current of the motor, the correction value of the second phase current of the motor, and the sampling value of the third phase current of the motor, and calculating the sampling value of the third phase current of the motor according to the relationship; wherein, the sampling value of the first phase current is such as the a-phase current Ia, the correction value of the first phase current is such as the correction value of the a-phase current Ic1, the sampling value of the second phase current is such as the b-phase current Ib, the correction value of the second phase current is such as the correction value of the b-phase current Ic2, and the sampling value of the third phase current is such as the c-phase current Ic.

[0114] The calculated sampling value of the third-phase current of the motor includes: an average value of the sampling values ​​of the third-phase current of the motor calculated at least twice. Specifically, the average value of the sampling values ​​of the third-phase current of the motor calculated at least twice is obtained after the steps of obtaining the current of the DC bus detected by the single current sensor to obtain the first current and the second current are repeated at least twice, and the steps of correcting and reconstructing the sampling values ​​of the first-phase current and the second-phase current based on the first current and the second current to obtain the sampling value of the third-phase current of the motor are repeated at least twice.

[0115] In the solution of the present invention, a three-phase two-level inverter is used, employing a TMS320F28335 digital signal processing (DSP) chip as the control chip, to drive a three-phase induction motor. In the three-phase two-level inverter, there is a corresponding relationship between the DC bus current Idc and the three-phase load currents Ia, Ib, and Ic. The relationship between the three-phase load currents Ia, Ib, and Ic can be expressed by Kirchhoff's current law:

[0116] I a +I b +I c =0 (1).

[0117] Among them, Ia is the a-phase current, Ib is the b-phase current, and Ic is the c-phase current.

[0118] By Figure 7 In the example shown, the DC bus current is sampled under different switching states of the switch tubes M1, M2, M3, M4, M5, and M6, and information of two-phase currents (such as the a-phase current Ia and the b-phase current Ib) can be obtained, and then the three-phase current (such as the c-phase current Ic) can be reconstructed.

[0119] like Figure 10 As shown, the DC bus voltage and current sampling and error compensation method also includes: Step 6, reconstructing the three-phase current: reconstructing the three-phase currents Ia, Ib, and Ic based on the corrected phase currents according to formula (1).

[0120] Step 7, multiple sampling and correction: By repeating steps 4, 5, and 6 for multiple sampling and correction, and finally taking the average value, the influence of zero drift on phase current reconstruction can be gradually reduced, and the accuracy of third phase current reconstruction can be improved.

[0121] In the solution of the present invention, the aforementioned steps enable real-time detection and correction of zero-point drift within each SVPWM modulation cycle, thereby improving the accuracy of third-phase current reconstruction and meeting the performance requirements of the motor control system. Specifically, the corrected phase current error is significantly reduced, meeting the performance requirements of the motor control system.

[0122] In three-phase, two-level inverters, the zero drift of a single DC bus current sensor (SCS) can reduce the accuracy of phase current reconstruction, thereby affecting the performance of the motor control system. While the use of multiple current sensors in related solutions can improve accuracy, it also increases system complexity and cost. The present invention, therefore, aims to provide a self-correction scheme for zero drift errors in a single DC bus current sensor based on complementary effective voltage vectors. This scheme inserts complementary effective voltage vectors during modulation, uses a single sensor for dual current sampling, and performs error compensation to improve the accuracy of third-phase current reconstruction while maintaining system simplicity and cost-effectiveness. This scheme has certain practical value. The present invention's scheme is not only applicable to three-phase, two-level inverters, but can also be extended to other types of inverters, such as three-phase multilevel inverters and single-phase inverters. Furthermore, the present invention's scheme can also be applied to other power electronics systems requiring precise current measurement, such as power converters and motor drive systems.

[0123] The present invention addresses the issue of inaccurate three-phase current sampling due to insufficient zero voltage vector duration. By using a single current sensor for current sampling, this reduces the need for multiple resistors compared to related solutions, thereby lowering hardware costs. This cost reduction is significant for mass-produced equipment. Using a single sensor simplifies and speeds installation, eliminating the need for separate resistors for each phase. This reduces installation time and complexity, reduces the probability of long-term failure, and makes replacement or repair more convenient.

[0124] The technical solution of this embodiment is adopted. By sampling the three-phase current provided by the power supply control terminal of the motor (such as the three-phase current output by the motor controller or the inverter in the frequency converter), when the motor is running, the reference voltage vector of the motor (such as the reference voltage vector Vref) is determined according to the operating parameters of the motor; according to the sector position of the motor reference voltage vector (that is, the position of the reference voltage vector Vref in the basic voltage vector diagram of SVPWM), a pair of complementary effective voltage vectors in the corresponding basic voltage vector is selected; in the self-calibration area of ​​the reference voltage vector of the motor, the complementary effective voltage vector is inserted to replace the zero in the SVPWM modulation method. Vector is used to determine the time of the current observation window (that is, the duration of the current observation window is greater than the minimum sampling time Tmin); within the current observation window, a single DC bus current sensor is used to dynamically double-sample the DC bus current according to the minimum sampling time to obtain two sampled currents; the two sampled currents are corrected to obtain two-phase currents; the third-phase current is obtained based on the two-phase current reconstruction to achieve the determination of the three-phase current of the motor; thus, by inserting a complementary effective voltage vector in the SVPWM modulation and dynamically double-sampling the DC bus current, error compensation of the two-phase current sampling values ​​is achieved, thereby improving the accuracy of the reconstruction of the third-phase current.

[0125] According to an embodiment of the present invention, a motor phase current determination device corresponding to the motor phase current determination method is also provided. Figure 6 The schematic diagram of the structure of an embodiment of the device of the present invention is shown. The power supply control end of the motor (such as a frequency converter or a motor controller) has a DC bus; a single current sensor is provided at the DC bus for detecting the current of the DC bus. Figure 7 It is a structural diagram of a three-phase bridge inverter circuit. Figure 7As shown, a three-phase bridge inverter circuit is disposed between a DC bus and a motor (PMSM). The three-phase bridge inverter circuit includes: switching transistors M1, M2, M3, M4, M5, and M6. Each switching transistor can be an IGBT, with the gate of the IGBT serving as the control terminal of each switching transistor, the collector of the IGBT serving as the first connection terminal of each switching transistor, and the emitter of the IGBT serving as the second connection terminal of each switching transistor. The positive terminal of the DC bus voltage V is connected to the first connection terminal of switching transistors M1, M2, and M3, respectively. The negative terminal of the DC bus voltage V is connected to the second connection terminal of switching transistors M4, M5, and M6, respectively. The second connection terminal of switching transistor M1 is connected to the first connection terminal of switching transistor M4, the second connection terminal of switching transistor M2 is connected to the first connection terminal of switching transistor M5, and the second connection terminal of switching transistor M3 is connected to the first connection terminal of switching transistor M6. The switch tube M1 and the switch tube M4 constitute the first phase bridge arm of the three-phase bridge arm, and the common end of the switch tube M1 and the switch tube M4 is connected to the first phase winding of the three-phase winding of the motor; the switch tube M2 and the switch tube M5 constitute the second phase bridge arm of the three-phase bridge arm, and the common end of the switch tube M2 and the switch tube M5 is connected to the second phase winding of the three-phase winding of the motor; the switch tube M3 and the switch tube M6 constitute the third phase bridge arm of the three-phase bridge arm, and the common end of the switch tube M3 and the switch tube M6 is connected to the third phase winding of the three-phase winding of the motor.

[0126] In the solution of the present invention, Figure 6 As shown, the method for determining the phase current of the motor includes: an acquisition unit 102 and a control unit 104.

[0127] The acquisition unit 102 is configured to acquire the operating parameters of the motor and the phase current parameters of the motor when the motor is running; wherein the phase current parameters of the motor include: a sampled value of the first phase current among the three-phase currents of the motor, and a sampled value of the second phase current among the three-phase currents of the motor. The phase current parameters of the motor can be sampled from the output end of the power supply control end of the motor (such as the output end of the inverter in the frequency converter or motor controller). The specific functions and processing of the acquisition unit 102 are shown in step S110.

[0128] The control unit 104 is configured to determine a reference voltage vector of the motor according to the operating parameters of the motor. Specific functions and processing of the control unit 104 are shown in step S120. Figure 10 The figure is a flow chart of DC bus voltage and current sampling and error compensation based on the self-correction of zero drift error of DC bus single current sensor with complementary effective voltage vector. Figure 10As shown, the voltage and current sampling and error compensation method of the DC bus includes:

[0129] Step 1: Calculate the reference voltage vector Vref according to the operating state of the motor, and then execute step 2.

[0130] In step 1, the reference voltage vector Vref is calculated according to the operating state of the motor, which specifically includes:

[0131] Step 11: Acquire the operating parameters of the motor. The acquired operating parameters of the motor include the motor speed, load current, temperature, etc., and then execute step 12.

[0132] Step 12: Determine a control target, such as maintaining stable operation of the motor, optimizing efficiency, etc., and then execute step 13.

[0133] Step 13: Calculate the reference voltage vector Vref: Based on the motor's mathematical model and control objectives, calculate the required reference voltage vector Vref. This typically involves the motor's electromagnetic equations and control algorithms, such as vector control.

[0134] The control unit 104 is further configured to insert a complementary effective voltage vector into the SVPWM modulation of the motor according to the reference voltage vector of the motor. Specific functions and processing of the control unit 104 are also described in step S130.

[0135] The acquisition unit 102 is further configured to acquire the DC bus current detected by the single current sensor twice during the time when the inserted complementary effective voltage vector is in effect, and record the current as a first current and a second current. The specific functions and processing of the acquisition unit 102 are further described in step S140.

[0136] The control unit 104 is further configured to correct and reconstruct the sampled values ​​of the first phase current and the second phase current based on the first current and the second current to obtain a sampled value of the third phase current of the motor, thereby determining the phase current of the motor. The specific functions and processing of the control unit 104 are further described in step S150.

[0137] The present invention proposes a DC bus voltage and current sampling and error compensation scheme that self-corrects zero-drift errors in a single DC bus current sensor based on complementary effective voltage vectors. By incorporating complementary effective voltage vectors and dynamic current dual sampling technology, this scheme achieves self-detection and self-correction of current zero-drift, improving the accuracy of phase current reconstruction. This scheme improves the accuracy of third-phase current reconstruction and reduces the impact of error amplification effects, while maintaining system simplicity and cost-effectiveness. It demonstrates excellent performance across various modulation regions and operating conditions, meeting the performance requirements of motor control systems.

[0138] In some embodiments, the control unit 104 inserts a complementary effective voltage vector into the SVPWM modulation of the motor according to the reference voltage vector of the motor, including:

[0139] The control unit 104 is further configured to select four valid voltage vectors for the sector position of the motor's reference voltage vector in the basic voltage vector diagram of SVPWM modulation, based on the sector position of the motor's reference voltage vector in the basic voltage vector diagram. The specific functions and processing of the control unit 104 are further described in step S210.

[0140] The control unit 104 is further configured to select a pair of complementary effective voltage vectors from the four effective voltage vectors, which are recorded as complementary effective voltage vectors. The specific functions and processing of the control unit 104 are also shown in step S220.

[0141] The control unit 104 is further configured to insert the complementary effective voltage vector within the self-calibration region of the motor's reference voltage vector, and to determine the duration of the inserted complementary effective voltage vector as the duration of the motor's current observation time window. The specific functions and processing of the control unit 104 are further described in step S230.

[0142] Figure 8 Figure 2 is a schematic diagram of the basic voltage vector synthesis modulation area. The inverter is controlled using space vector pulse width modulation (SVPWM) technology. By linearly combining the basic voltage space vectors, the stator flux inside the motor forms a vector circle, thus ensuring stable electromagnetic torque output by the motor. Figure 8 In the figure, the self-calibration area includes: low modulation area, overmodulation area and sector boundary; the sectors include: sector I, sector II, sector III, sector IV, sector V, sector VI; the unobservable area includes: the area within the dotted line; the basic voltage vectors include: vector V0, vector V1, vector V2, vector V3, vector V4, vector V5, vector V6, vector V7, and vector V0 and vector V7 are located in the center circle ( Figure 8 not shown).

[0143] like Figure 8 As shown, corresponding to the switching states of the upper bridge arm (000, 001, 010, 011, 100, 101, 110, 111), the motor has eight basic voltage space vectors: V0, V1, V2, V3, V4, V5, V6, and V7. For the upper bridge arm switching state 000, the motor's basic voltage space vector is V0; for the upper bridge arm switching state 001, the motor's basic voltage space vector is V1; for the upper bridge arm switching state 010, the motor's basic voltage space vector is V2; for the upper bridge arm switching state 011, the motor's basic voltage space vector is V3; for the upper bridge arm switching state 100, the motor's basic voltage space vector is V4; for the upper bridge arm switching state 101, the motor's basic voltage space vector is V5; for the upper bridge arm switching state 110, the motor's basic voltage space vector is V6; and for the upper bridge arm switching state 111, the motor's basic voltage space vector is V7. Among them, V1, V2, V3, V4, V5, V6 are valid vectors, V0 and V7 are zero vectors, corresponding to Figure 8 The most central circle area (in Figure 8 not shown).

[0144] Figure 9 Schematic diagram for inserting complementary effective voltage vectors. Figure 9 In the figure, the solid line is the basic voltage vector, the dashed line is the sector boundary, and the red line is the component of the reference voltage decomposed into the basic voltage vector.

[0145] In the SVPWM modulation method, the basic voltage vector action time of each sector determines the duration of the current observation window. In order to ensure accurate current sampling, it is necessary to analyze the duration of the current observation window of each sector. Specifically, Figure 8 and Figure 9 As shown, when the reference voltage vector Vref is located in an unobservable area (ie, a sector boundary or an overmodulation area), the action time of the effective voltage vector may be less than the minimum sampling time Tmin, resulting in an inability to accurately collect the current.

[0146] To extend the current observation window, the present invention proposes inserting complementary effective voltage vectors into the SVPWM modulation method, replacing the zero vector used in related schemes. The present invention addresses the inaccurate sampling problem of the SVPWM method in unobservable regions in related schemes by inserting complementary effective voltage vectors in place of the zero vector. The use of complementary effective voltage vectors ensures that the current observation window is longer than the minimum sampling time, improving current sampling accuracy.

[0147] like Figure 10As shown, the DC bus voltage and current sampling and error compensation method also includes:

[0148] Step 2: Select a suitable basic voltage vector according to the position of the reference voltage vector Vref, and then execute step 3.

[0149] In step 2, according to the position of the reference voltage vector Vref, a suitable basic voltage vector is selected, which specifically includes:

[0150] Step 21, determine the position of the reference voltage vector Vref, and then execute step 22. In step 21, specifically, the reference voltage vector Vref is projected onto the basic voltage vector diagram of SVPWM, such as Figure 8 As shown, the sector where the reference voltage vector Vref is located is determined.

[0151] Step 22, select the basic voltage vector: select a suitable basic voltage vector according to the position of the reference voltage vector Vref in the basic voltage vector diagram of SVPWM, and then execute step 23.

[0152] like Figure 8 As shown, the basic voltage vector diagram of SVPWM is divided into six sectors, each sector corresponding to a set of basic voltage vectors. For example, if the reference voltage vector Vref is located in the first sector (i.e., sector I), vector V6, vector V1, vector V2, and vector V3 are selected as the basic voltage vectors. If the reference voltage vector Vref is located in the second sector (i.e., sector II), vector V1, vector V2, vector V3, and vector V4 are selected as the basic voltage vectors. If the reference voltage vector Vref is located in the third sector (i.e., sector III), vector V2, vector V3, vector V4, and vector V5 are selected as the basic voltage vectors. If the reference voltage vector Vref is located in the fourth sector (i.e., sector IV), vector V3, vector V4, vector V5, and vector V6 are selected as the basic voltage vectors. If the reference voltage vector Vref is located in the fifth sector (i.e., sector V), vector V4, vector V5, vector V6, and vector V1 are selected as the basic voltage vectors. If the reference voltage vector Vref is located in the sixth sector (ie, sector VI), vector V5, vector V6, vector V1, and vector V2 are selected as basic voltage vectors.

[0153] Step 23, calculating the action time: calculating the action time of each basic voltage vector in the selected basic voltage vectors according to the position of the reference voltage vector Vref and the modulation algorithm of SVPWM.

[0154] Step 3: Insert the complementary effective voltage vector in the selected basic voltage vector into the self-correction region of the reference voltage vector Vref, and then execute step 4.

[0155] In step 3, two adjacent effective voltage vectors (i.e., complementary effective voltage vectors) are used to replace the sporadic vectors (i.e., vector V0 and vector V7) to ensure that the duration of the current observation window is greater than the minimum sampling time Tmin. The duration of the current observation window is as follows: Figure 8 The time Ts is shown.

[0156] In step 3, a complementary effective voltage vector of the selected basic voltage vector is inserted into the self-correction region of the reference voltage vector Vref, specifically including:

[0157] Step 31: Determine the self-correction region of the reference voltage vector Vref, and then proceed to step 32. Figure 8 As shown in the figure, the self-correction region of the reference voltage vector Vref includes: the undermodulation region, the overmodulation region, and the sector boundary. During the SVPWM modulation process, when the reference voltage vector Vref is located in an unobservable region (such as a sector boundary or overmodulation region), the zero vector action time in the relevant scheme may be less than the minimum sampling time Tmin. Therefore, it is necessary to use two adjacent effective voltage vectors (i.e., complementary effective voltage vectors) to replace the zero vectors (i.e., vectors V0 and V7) to ensure that the duration of the current observation window is greater than the minimum sampling time Tmin.

[0158] Step 32: Select a complementary effective voltage vector in the self-correction region of the reference voltage vector Vref, and then execute step 33. In step 32, in the self-correction region of the reference voltage vector Vref, select two adjacent effective voltage vectors to replace the zero vector (ie, vector V0 and vector V7).

[0159] For example, if the self-correction region of the reference voltage vector Vref is in the first sector (i.e., sector I), then the complementary effective voltage vectors such as vector V6 and vector V3 from among the basic voltage vectors such as vector V6, vector V1, vector V2, and vector V3 are selected. If the self-correction region of the reference voltage vector Vref is in the second sector (i.e., sector II), then the complementary effective voltage vectors such as vector V1 and vector V4 from among the basic voltage vectors such as vector V1, vector V2, vector V3, and vector V4 are selected. If the self-correction region of the reference voltage vector Vref is in the third sector (i.e., sector III), then the complementary effective voltage vectors such as vector V2 and vector V5 from among the basic voltage vectors such as vector V2, vector V3, vector V4, and vector V5 are selected. If the self-correction region of the reference voltage vector Vref is in the fourth sector (i.e., sector IV), then the complementary effective voltage vectors such as vector V3 and vector V6 from among the basic voltage vectors such as vector V3, vector V4, vector V5, and vector V6 are selected. If the self-correction region of the reference voltage vector Vref is in the fifth sector (i.e., sector V), then complementary effective voltage vectors such as vectors V4 and V1 are selected from among the basic voltage vectors such as vectors V4, V5, V6, and V1. If the self-correction region of the reference voltage vector Vref is in the sixth sector (i.e., sector VI), then complementary effective voltage vectors such as vectors V5 and V2 are selected from among the basic voltage vectors such as vectors V5, V6, V1, and V2.

[0160] Step 33: Allocate the action time: divide the action time T0 of the zero vector equally between the two complementary effective voltage vectors. For example, if the self-correction region of the reference voltage vector Vref is in the first sector (i.e., sector I), then select the complementary effective voltage vectors such as vector V6 and vector V3 from the basic voltage vectors such as vector V6, vector V1, vector V2, and vector V3, and divide the action time T0 of the zero vector equally between the two complementary effective voltage vectors such as vector V6 and vector V3, as follows:

[0161] V0*T0=V3*T0 / 2+V6*T0 / 2 (2).

[0162] In the solution of the present invention, by inserting a complementary effective voltage vector from the selected basic voltage vector within the self-correction region of the reference voltage vector Vref, the action time T0 of the zero vector can be equally divided into two complementary effective voltage vectors such as vector V6 and vector V3, thereby ensuring that the duration of the current observation window is greater than the minimum sampling time Tmin, thereby improving the accuracy of current sampling.

[0163] Specifically, taking sector I as an example, within the self-correction region of the reference voltage vector Vref, the zero vectors V0 and V7 in the SVPWM switching sequence in the relevant scheme are replaced by two adjacent effective voltage vectors V3 and V6, as shown in Figure 8As shown in Figure 2, the action time T0 of the zero vector is divided equally into two complementary effective voltage vectors, which is formula (2).

[0164] In different sectors, the switching sequence for inserting complementary effective voltage vectors is shown in Table 1.

[0165] In some embodiments, the acquiring unit 102 acquires the current of the DC bus detected by the single current sensor twice within the time when the inserted complementary effective voltage vector acts, and records the acquired current as a first current and a second current, including:

[0166] The acquisition unit 102 is further configured to acquire a minimum sampling time pre-determined based on the hardware performance of the motor. The specific functions and processing of the acquisition unit 102 are also referred to in step S310.

[0167] The acquisition unit 102 is further configured to acquire the DC bus current detected by the single current sensor twice at the minimum sampling time within the time period of the inserted complementary effective voltage vector, and record these as a first current and a second current. Specifically, within the current observation time window of the motor, the DC bus current sampled twice by the single current sensor at the predetermined minimum sampling time is acquired, and record these as the first current and the second current. For example, within the time period of the inserted complementary effective voltage vector, the DC bus current detected by the single current sensor at the minimum sampling time is acquired for the first time, and record these as the first current; and, still within the time period of the inserted complementary effective voltage vector, the DC bus current detected by the single current sensor at the minimum sampling time is acquired for the second time, and record these as the second current. The sum of the sampling times of the first and second currents is less than the time period of the inserted complementary effective voltage vector. See step S320 for the specific functions and processing of the acquisition unit 102.

[0168] like Figure 10 As shown, the DC bus voltage and current sampling and error compensation method also includes: step 4, after inserting the complementary effective voltage vector in the selected basic voltage vector within the self-correction area of ​​the reference voltage vector Vref, double sampling of the DC bus current based on the inserted complementary voltage vector to obtain sampled currents I1 and I2, and then executing step 5.

[0169] In step 4, the DC bus current is double sampled based on the inserted complementary voltage vector to obtain the sampled currents I1 and I2. The specific sampling method is as follows:

[0170] Step 41 , calculating the minimum sampling time Tmin: Calculate the minimum sampling time Tmin based on the performance of the hardware device, and then execute step 42 .

[0171] Step 42 , performing double current sampling on the DC bus current: within the inserted complementary voltage vector action time (such as time Ts), using a single current sensor, based on the minimum sampling time Tmin, perform two samplings on the DC bus current to obtain sampling currents I1 and I2.

[0172] In the solution of the present invention, the dynamic current double current sampling technology is used to achieve self-detection and self-correction of the current zero drift, thereby improving the accuracy of the third-phase current reconstruction.

[0173] In some embodiments, the control unit 104 corrects and reconstructs the sampled value of the first phase current and the sampled value of the second phase current based on the first current and the second current to obtain the sampled value of the third phase current of the motor, thereby determining the phase current of the motor, including:

[0174] The control unit 104 is further configured to correct the sampled values ​​of the first-phase current and the second-phase current based on the first current and the second current to obtain a first corrected current and a second corrected current, which are recorded as the corrected value of the first-phase current of the motor and the corrected value of the second-phase current of the motor. The specific functions and processing of the control unit 104 are further described in step S410.

[0175] The control unit 104 is further configured to perform current reconstruction based on the corrected value of the first phase current of the motor and the corrected value of the second phase current of the motor to obtain a sampled value of the third phase current of the motor. The specific functions and processing of the control unit 104 are further described in step S420.

[0176] In the solution of the present invention, an error self-correction strategy is proposed by analyzing the duration of the current observation window of each sector, which can effectively reduce the impact of zero point drift on phase current reconstruction under different modulation areas and working conditions.

[0177] In some embodiments, the control unit 104 corrects the sampled value of the first phase current and the sampled value of the second phase current based on the first current and the second current to obtain a first corrected current and a second corrected current, including:

[0178] The control unit 104 is further configured to use the sum of the first current and the second current as the zero drift. The specific functions and processing of the control unit 104 are also shown in step S510.

[0179] The control unit 104 is further configured to use the difference between the sampled value of the first phase current and the zero drift as a first correction current, and to use the difference between the sampled value of the second phase current and the zero drift as a second correction current. The specific functions and processing of the control unit 104 are further described in step S520.

[0180] like Figure 10 As shown, the DC bus voltage and current sampling and error compensation method further includes: step 5, correcting the sampled currents I1 and I2 to perform error compensation, and then executing step 6.

[0181] In step 5, the sampled currents I1 and I2 are calibrated, specifically including:

[0182] Step 51 , calculating the zero-point drift Ie: calculating the zero-point drift Ie according to the sampled current: 2Ie=I1+I2, and then executing step 52.

[0183] Step 52 , correcting the sampling current: correcting the sampling current using the zero-point drift Ie to obtain corrected phase currents Ic1 and Ic2 .

[0184] In the solution of the present invention, dynamic current dual current sampling: using complementary effective voltage vector dynamic current dual current sampling, self-detection and self-correction of current zero drift are realized, and the impact of zero drift on current reconstruction accuracy is effectively reduced without adding additional hardware equipment.

[0185] In some embodiments, the control unit 104 performs current reconstruction based on the correction value of the first phase current of the motor and the correction value of the second phase current of the motor to obtain the sampling value of the third phase current of the motor, including: the control unit 104 is specifically configured to determine the relationship between the correction value of the first phase current of the motor, the correction value of the second phase current of the motor, and the sampling value of the third phase current of the motor based on Kirchhoff's current law, and calculate the sampling value of the third phase current of the motor according to the relationship; wherein, the sampling value of the first phase current is such as the a-phase current Ia, the correction value of the first phase current is such as the correction value of the a-phase current Ic1, the sampling value of the second phase current is such as the b-phase current Ib, the correction value of the second phase current is such as the correction value of the b-phase current Ic2, and the sampling value of the third phase current is such as the c-phase current Ic.

[0186] The sampling value of the third phase current of the motor calculated by the control unit 104 includes: the control unit 104 is further configured to calculate an average value of the sampling values ​​of the third phase current of the motor obtained by more than two calculations. Specifically, after the acquisition unit 102 repeatedly executes the step of acquiring the current of the DC bus detected by the single current sensor to obtain the first current and the second current twice or more, and the control unit 104 repeatedly executes the step of correcting and reconstructing the sampling value of the first phase current and the sampling value of the second phase current based on the first current and the second current to obtain the sampling value of the third phase current of the motor twice or more, the average value of the sampling values ​​of the third phase current of the motor calculated more than twice is obtained.

[0187] In the solution of the present invention, a three-phase two-level inverter is used, employing a TMS320F28335 digital signal processing (DSP) chip as the control chip, to drive a three-phase induction motor. In the three-phase two-level inverter, there is a corresponding relationship between the DC bus current Idc and the three-phase load currents Ia, Ib, and Ic. The relationship between the three-phase load currents Ia, Ib, and Ic can be expressed by Kirchhoff's current law:

[0188] I a +I b +I c =0 (1).

[0189] Among them, Ia is the a-phase current, Ib is the b-phase current, and Ic is the c-phase current.

[0190] By Figure 7 In the example shown, the DC bus current is sampled under different switching states of the switch tubes M1, M2, M3, M4, M5, and M6, and information of two-phase currents (such as the a-phase current Ia and the b-phase current Ib) can be obtained, and then the three-phase current (such as the c-phase current Ic) can be reconstructed.

[0191] like Figure 10 As shown, the DC bus voltage and current sampling and error compensation method also includes: Step 6, reconstructing the three-phase current: reconstructing the three-phase currents Ia, Ib, and Ic based on the corrected phase currents according to formula (1).

[0192] Step 7, multiple sampling and correction: By repeating steps 4, 5, and 6 for multiple sampling and correction, and finally taking the average value, the influence of zero drift on phase current reconstruction can be gradually reduced, and the accuracy of third phase current reconstruction can be improved.

[0193] In the solution of the present invention, the aforementioned steps enable real-time detection and correction of zero-point drift within each SVPWM modulation cycle, thereby improving the accuracy of third-phase current reconstruction and meeting the performance requirements of the motor control system. Specifically, the corrected phase current error is significantly reduced, meeting the performance requirements of the motor control system.

[0194] In three-phase, two-level inverters, the zero drift of a single DC bus current sensor (SCS) can reduce the accuracy of phase current reconstruction, thereby affecting the performance of the motor control system. While the use of multiple current sensors in related solutions can improve accuracy, it also increases system complexity and cost. The present invention, therefore, aims to provide a self-correction scheme for zero drift errors in a single DC bus current sensor based on complementary effective voltage vectors. This scheme inserts complementary effective voltage vectors during modulation, uses a single sensor for dual current sampling, and performs error compensation to improve the accuracy of third-phase current reconstruction while maintaining system simplicity and cost-effectiveness. This scheme has certain practical value. The present invention's scheme is not only applicable to three-phase, two-level inverters, but can also be extended to other types of inverters, such as three-phase multilevel inverters and single-phase inverters. Furthermore, the present invention's scheme can also be applied to other power electronics systems requiring precise current measurement, such as power converters and motor drive systems.

[0195] The present invention addresses the issue of inaccurate three-phase current sampling due to insufficient zero voltage vector duration. By using a single current sensor for current sampling, this reduces the need for multiple resistors compared to related solutions, thereby lowering hardware costs. This cost reduction is significant for mass-produced equipment. Using a single sensor simplifies and speeds installation, eliminating the need for separate resistors for each phase. This reduces installation time and complexity, reduces the probability of long-term failure, and makes replacement or repair more convenient.

[0196] Since the processing and functions implemented by the device of this embodiment basically correspond to the embodiments, principles and examples of the aforementioned method, for any details not fully described in this embodiment, please refer to the relevant descriptions in the aforementioned embodiments and will not be repeated here.

[0197] According to an embodiment of the present invention, a motor corresponding to the phase current determination device of the motor is further provided. The motor may include: the phase current determination device of the motor described above.

[0198] Since the processing and functions implemented by the motor of this embodiment basically correspond to the embodiments, principles and examples of the aforementioned device, for any details not fully described in this embodiment, please refer to the relevant descriptions in the aforementioned embodiments and will not be repeated here.

[0199] According to an embodiment of the present invention, a computer program product corresponding to the method for determining the phase current of a motor is also provided, comprising a computer program. When the computer program is executed by a processor, the steps of the method for determining the phase current of the motor are implemented.

[0200] Since the processing and functions implemented by the product of this embodiment basically correspond to the embodiments, principles and examples of the aforementioned method, for any details not fully described in this embodiment, please refer to the relevant descriptions in the aforementioned embodiments and will not be repeated here.

[0201] According to an embodiment of the present invention, a storage medium corresponding to a method for determining the phase current of a motor is also provided, wherein the storage medium includes a stored program, wherein when the program is running, the device where the storage medium is located is controlled to execute the steps of the method for determining the phase current of the motor described above.

[0202] Since the processing and functions implemented by the storage medium of this embodiment basically correspond to the embodiments, principles and examples of the aforementioned method, for any details not fully described in this embodiment, please refer to the relevant descriptions in the aforementioned embodiments and will not be repeated here.

[0203] In summary, it is easy for those skilled in the art to understand that, under the premise of no conflict, the above-mentioned advantageous methods can be freely combined and superimposed.

[0204] The foregoing description is merely an embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of the claims.

Claims

1. A method for determining the phase current of a motor, characterized in that: The power supply control end of the motor has a DC bus; a single current sensor is provided at the DC bus for detecting the current of the DC bus; The method for determining the phase current of the motor includes: When the motor is running, obtaining the operating parameters of the motor and the phase current parameters of the motor; wherein the phase current parameters of the motor include: a sampled value of a first phase current among the three-phase currents of the motor, and a sampled value of a second phase current among the three-phase currents of the motor; determining a reference voltage vector of the motor according to operating parameters of the motor; inserting a complementary effective voltage vector into the SVPWM modulation of the motor according to the reference voltage vector of the motor; within the time when the inserted complementary effective voltage vector acts, acquiring the current of the DC bus detected by the single current sensor twice, and recording them as a first current and a second current; Based on the first current and the second current, the sampling value of the first phase current and the sampling value of the second phase current are corrected and reconstructed to obtain the sampling value of the third phase current of the motor, thereby determining the phase current of the motor.

2. The method for determining the phase current of a motor according to claim 1, wherein: Inserting a complementary effective voltage vector into the SVPWM modulation of the motor according to the reference voltage vector of the motor comprises: According to the sector position of the reference voltage vector of the motor in the basic voltage vector diagram of SVPWM modulation, four effective voltage vectors at the sector position are selected from the basic voltage vector; Select a pair of complementary effective voltage vectors from the four effective voltage vectors and record them as complementary effective voltage vectors; The complementary effective voltage vector is inserted into the self-calibration region of the reference voltage vector of the motor, so that the time when the inserted complementary effective voltage vector acts is determined as the time of the current observation time window of the motor.

3. The method for determining the phase current of a motor according to claim 1 or 2, characterized in that: Acquiring the current of the DC bus detected by the single current sensor twice within the time when the inserted complementary effective voltage vector acts, and recording them as a first current and a second current, comprising: Obtaining a minimum sampling time predetermined based on hardware performance of the motor; During the time when the inserted complementary effective voltage vector acts, the current of the DC bus detected by the single current sensor is acquired twice according to the minimum sampling time, and recorded as a first current and a second current.

4. The method for determining the phase current of a motor according to any one of claims 1 to 3, characterized in that: Based on the first current and the second current, correcting and reconstructing the sampled value of the first phase current and the sampled value of the second phase current to obtain the sampled value of the third phase current of the motor, thereby determining the phase current of the motor, including: Based on the first current and the second current, correcting the sampled value of the first phase current and the sampled value of the second phase current to obtain a first corrected current and a second corrected current, which are recorded as a corrected value of the first phase current of the motor and a corrected value of the second phase current of the motor; Current reconstruction is performed according to the correction value of the first phase current of the motor and the correction value of the second phase current of the motor to obtain a sampling value of the third phase current of the motor.

5. The method for determining the phase current of a motor according to claim 4, characterized in that: Correcting the sampled value of the first phase current and the sampled value of the second phase current based on the first current and the second current to obtain a first corrected current and a second corrected current includes: Taking the sum of the first current and the second current as the zero point drift; The difference between the sampling value of the first phase current and the zero drift is used as the first correction current; and the difference between the sampling value of the second phase current and the zero drift is used as the second correction current.

6. The method for determining the phase current of a motor according to claim 4, wherein: Current reconstruction is performed according to the correction value of the first phase current of the motor and the correction value of the second phase current of the motor to obtain a sampled value of the third phase current of the motor, including: Based on Kirchhoff's current law, determining a relationship among a correction value of a first phase current of the motor, a correction value of a second phase current of the motor, and a sampled value of a third phase current of the motor, and calculating the sampled value of the third phase current of the motor according to the relationship; The calculated sampling value of the third phase current of the motor includes: an average value of the sampling values ​​of the third phase current of the motor calculated more than twice.

7. A device for determining phase current of a motor, characterized in that: The power supply control terminal of the motor has a DC bus; a single current sensor is provided at the DC bus for detecting the current of the DC bus; the method for determining the phase current of the motor includes: an acquisition unit configured to acquire, when the motor is running, operating parameters of the motor and phase current parameters of the motor; wherein the phase current parameters of the motor include: a sampled value of a first phase current among the three-phase currents of the motor, and a sampled value of a second phase current among the three-phase currents of the motor; a control unit configured to determine a reference voltage vector of the motor according to operating parameters of the motor; The control unit is further configured to insert a complementary effective voltage vector in the SVPWM modulation of the motor according to the reference voltage vector of the motor; The acquisition unit is further configured to acquire the current of the DC bus detected by the single current sensor twice within the time when the inserted complementary effective voltage vector acts, and record them as a first current and a second current; The control unit is also configured to correct and reconstruct the sampling value of the first phase current and the sampling value of the second phase current based on the first current and the second current, obtain the sampling value of the third phase current of the motor, and determine the phase current of the motor.

8. A motor, characterized in that: include: The phase current determining device for a motor as claimed in claim 7.

9. A storage medium, characterized in that: The storage medium includes a stored program, wherein when the program is executed, the device where the storage medium is located is controlled to execute the method for determining the phase current of the motor according to any one of claims 1 to 6.

10. A computer program product comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of the method for determining the phase current of a motor according to any one of claims 1 to 6 are implemented.

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