Method, apparatus, and medium for single-resistor reconstruction of motor three-phase current

Abstract

Embodiments of the present disclosure relate to a method and device for reconstructing three-phase currents of a motor with a single resistor, the method comprising: calculating a modulation wave and constructing a reduced count PWM sawtooth wave as a carrier wave based on a current reference value, a current feedback value and an electrical angle value of a circuit; comparing the calculated modulation wave with a first phase carrier wave to generate a first phase voltage; performing corresponding phase shift processing on a second phase carrier wave and a third phase carrier wave based on a current sampling point time window length of a test circuit with reference to the first phase voltage, so as to construct a second phase voltage and a third phase voltage; determining a first phase current in response to a first current sampling point time window and determining a second phase current in response to a second current sampling point time window; and reconstructing a third phase current based on the determined first phase current and the second phase current.

Description

Technical Field

[0001] This invention relates to the field of motor control technology, and more specifically, to a method, apparatus, and medium for reconstructing the three-phase current of a motor using a single resistor. Background Technology

[0002] To achieve high-performance motor control, it is typically necessary to detect the current in each phase winding. Real-time current detection outputs a PWM drive signal to control the switching devices of the three-phase inverter. The phase current magnitude can usually be obtained through resistor voltage division. However, to reduce costs, only two current sensors are needed to reconstruct the three-phase current magnitude, since the sum of the three-phase currents is always zero under normal operating conditions (i.e., Ia + Ib + Ic = 0). This method saves one current sensor.

[0003] Current solutions using magnetic or photoelectric current sensors to acquire reconstructed three-phase motor currents suffer from high cost and large product size. Using a three-resistor shunt method in the lower bridge arm requires three identical sampling hardware circuits, but inconsistencies in hardware parameters can affect the accuracy of motor phase current reconstruction.

[0004] In recent years, the method of reconstructing the three-phase current of a motor using a single resistor has been adopted. This method only requires placing a single sampling resistor at the DC bus position. Based on the relationship between the different switching states and the bus current within one carrier cycle of the SVPWM waveform generation method, the ADC sampling is triggered twice within one carrier cycle to reconstruct the three-phase current of the motor.

[0005] In existing inverter circuits, various current sampling schemes can be employed to obtain the output three-phase current. Common methods include direct sampling of the output phase lines, sampling using three or two resistors in the lower bridge arm, and single-resistor sampling. The single-resistor sampling scheme is widely used due to its simple circuitry, small PCB footprint, and low overall cost.

[0006] However, single-resistor sampling schemes require complex software algorithms to reconstruct the three-phase output current of the inverter. Current reconstruction methods proposed in existing patents such as CN115642852A, CN115776261A, and CN118707184A generally employ a seven-segment SVPWM (Space Vector Pulse Width Modulation) waveform generation method with incrementing and decrementing counting, requiring extensive software code and complex mathematical and logical operations. Further complicating matters, when the output voltage is low, the current sampling window is too small, leading to sampling failures. This necessitates shifting the sampling window to allow sufficient sampling time, further increasing the complexity of the current reconstruction algorithm.

[0007] Therefore, a method is needed to reconstruct the three-phase current simply by decrementing the count or by performing a translation process on the sampling window. Summary of the Invention

[0008] To address the aforementioned problems, this disclosure provides a method for reconstructing the three-phase current of a motor using a single resistor. The method includes: calculating a modulation wave based on the circuit's current reference value, current feedback value, and electrical angle value, and constructing a counted PWM sawtooth wave as a carrier wave; comparing the calculated modulation wave with the first phase carrier wave to generate a first phase voltage; using the first phase voltage as a reference, and based on the current sampling point time window length of the test circuit, performing corresponding phase shifting processing on the second phase carrier wave and the third phase carrier wave respectively, thereby constructing the second phase voltage and the third phase voltage; determining the first phase current in response to the first current sampling point time window and determining the second phase current in response to the second current sampling point time window; and reconstructing the third phase current based on the determined first phase current and second phase current.

[0009] In one embodiment, determining the first phase current in response to a first current sampling point time window and determining the second phase current in response to a second current sampling point time window includes: generating a trigger signal via a microcontroller unit timer to determine the start time of the current sampling point time window; triggering sampling of the first phase current at the start time of the first current sampling point time window; and triggering sampling of the second phase current in the second current sampling point time window according to a fixed phase shift, ensuring that the current sampling point time windows do not overlap.

[0010] In one embodiment, the method further includes: the microcontroller unit calculating the impact of dead time on current measurement based on preset dead time parameters; during the third phase current reconstruction, performing real-time correction on the measured current value based on the dead time offset within the time window of the first current sampling point and the time window of the second current sampling point; dynamically compensating for the current error of dead time according to different phase and load conditions; and using the dynamically compensated current value for further current reconstruction to improve the accuracy of current reconstruction.

[0011] In one embodiment, the method further includes: calculating the deviations between the measured values ​​and theoretical values ​​of the currently determined first-phase current and second-phase current; adjusting the PWM sawtooth wave to reduce the deviation based on the circuit's load conditions and motor parameters; and feeding back the corrected current measurement value to the microcontroller unit for use in the next PWM modulation.

[0012] In one embodiment, reconstructing the third phase current based on the determined first and second phase currents includes: within the current sampling time window, the microcontroller optimizes the sampling time by controlling the phase offset of the PWM signal to ensure that the current sampling time window falls within the stable region of the current waveform; during the current reconstruction calculation, the microcontroller adjusts the sampling time to match the dead time based on the current change trend within the current sampling time window to eliminate the current waveform distortion caused by the dead time; and the microcontroller monitors load changes in real time and dynamically adjusts the dead time compensation strategy to adapt to different load conditions.

[0013] In one embodiment, the sampling window for the first phase current and the second phase current is set in the range of 1-5 microseconds, and a fixed phase shift is used to ensure the relative timing stability of the sampling window and reduce the impact of PWM dead time.

[0014] In one embodiment, the single-sided sawtooth PWM signal is generated using an MCU counter and comparator to ensure accurate timing of PWM waveform modulation and to optimize the position of the current sampling window based on the PWM waveform. The phase shift of the phase voltage corresponds to the length of the sampling window.

[0015] In one embodiment, the first phase is the U phase, the second phase is the V phase, and the third phase is the W phase.

[0016] In a second aspect, a current reconfiguration device for a three-phase motor inverter is provided, the current reconfiguration device reconfiguring the three-phase current using the method described above, including: a microcontroller unit (MCU) configured to generate and control a single-sided sawtooth wave PWM signal and perform phase shift modulation to match the current sampling window, perform current sampling and three-phase current reconfiguration; a single resistor configured for current sampling and connected to the common circuit of the lower bridge arm of the inverter; a sampling analog-to-digital converter (ADC) configured to convert the current signal sampled by the single resistor into a digital signal and input it to the MCU; and a MOSFET transistor including an upper transistor and a lower transistor, configured to drive a three-phase motor.

[0017] In one embodiment, the conduction mode of the MOSFET transistor corresponds to the current sampling time window. Specifically, in the first sampling window, the MCU controls the MOSFET to turn on the upper U-phase transistor, the lower V-phase transistor, and the lower W-phase transistor, so that the current flowing through the single resistor corresponds to the U-phase current; in the second sampling window, the MCU controls the MOSFET to turn on the upper U-phase transistor, the upper V-phase transistor, and the lower W-phase transistor, so that the current flowing through the single resistor corresponds to the negative value of the W-phase current; and based on the measured currents of the U-phase and W-phase, the MCU calculates the V-phase current using the three-phase current reconstruction method to complete the reconstruction of the three-phase current.

[0018] According to a third aspect of this disclosure, a computing device is provided, comprising: at least one processor; and a memory communicatively connected to the at least one processor; the memory storing instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to perform the method of the first aspect of this disclosure.

[0019] In a fourth aspect of this disclosure, a non-transitory computer-readable storage medium is provided storing computer instructions, wherein the computer instructions are used to cause a computer to perform the method of the first aspect of this disclosure.

[0020] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of this disclosure, nor is it intended to limit the scope of this disclosure. Other features of this disclosure will become readily apparent from the following description. Attached Figure Description

[0021] The above and other features, advantages, and aspects of the embodiments of this disclosure will become more apparent from the accompanying drawings and the following detailed description. In the drawings, the same or similar reference numerals denote the same or similar elements.

[0022] Figure 1 A schematic diagram of a system 100 for implementing a method for reconstructing the three-phase current of a motor using a single resistor according to an embodiment of the present disclosure is shown.

[0023] Figure 2 A flowchart of a method 200 for reconstructing the three-phase current of a motor using a single resistor according to an embodiment of the present disclosure is shown.

[0024] Figure 3 A schematic diagram of a circuit for reconstructing the three-phase current of a motor using a single resistor according to an embodiment of the present disclosure is shown.

[0025] Figure 4 A schematic diagram of the voltage and current of a single-resistor reconfiguration motor three-phase current according to an embodiment of the present disclosure is shown.

[0026] Figure 5 A schematic block diagram of an example electronic device 500 that can be used to implement embodiments of the present disclosure is shown. Detailed Implementation

[0027] The exemplary embodiments of this disclosure are described below with reference to the accompanying drawings, including various details of the embodiments to aid understanding, and should be considered merely exemplary. Therefore, those skilled in the art will recognize that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of this disclosure. Similarly, for clarity and brevity, descriptions of well-known functions and structures are omitted in the following description.

[0028] The term "comprising" and its variations as used herein signify open inclusion, i.e., "including but not limited to". Unless otherwise stated, the term "or" means "and / or". The term "based on" means "at least partially based on". The terms "one example embodiment" and "one embodiment" mean "at least one example embodiment". The term "another embodiment" means "at least one additional embodiment". The terms "first", "second", etc., may refer to different or the same objects. Other explicit and implicit definitions may also be included below.

[0029] Figure 1 A schematic diagram of a system 100 for implementing a method for reconstructing the three-phase current of a motor using a single resistor according to embodiments of the present disclosure is shown. Figure 1 As shown, system 100 includes a computing device 110, a motor three-phase current reconfiguration device 130, and a network 140. The computing device 110 and the motor three-phase current reconfiguration device 130 can interact with each other via the network 140.

[0030] The motor three-phase current reconfiguration device 130 can, for example, perform functions such as reconfiguring the three-phase current of an inverter motor. The motor three-phase current reconfiguration device 130 can also send a determined reconfiguration current to a computing device 110. The motor three-phase current reconfiguration device 130 may have one or more processing units, including dedicated processing units such as MCUs, GPUs, FPGAs, and ASICs, as well as general-purpose processing units such as CPUs, for example, but not limited to: desktop computers, laptop computers, netbook computers, tablet computers, web browsers, e-book readers, personal digital assistants (PDAs), and wearable computers (such as smartwatches and activity tracker devices) capable of reading and modifying Chinese data.

[0031] Regarding computing device 110, it is used, for example, to receive voltage compensation data from motor three-phase current reconfiguration device 130 via network 140. Computing device 110 may have one or more processing units, including dedicated processing units such as GPUs, FPGAs, and ASICs, and general-purpose processing units such as CPUs. Additionally, one or more virtual machines may run on each computing device 110. In some embodiments, computing device 110 and motor three-phase current reconfiguration device 130 may be integrated together or configured separately.

[0032] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention in conjunction with practical applications. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them.

[0033] Figure 2A flowchart of a method 200 for reconstructing three-phase current of a motor using a single resistor according to an embodiment of the present disclosure is shown. Method 200 can be performed by, for example... Figure 1 The computing device 110 shown can be used for execution, and can also be used in Figure 5 The method is performed at the illustrated electronic device 500. It should be understood that method 200 may also include additional boxes not shown and / or the boxes shown may be omitted, and the scope of this disclosure is not limited in this respect.

[0034] This embodiment provides a current reconstruction method and device for a three-phase motor inverter. The method adopts a single-resistor current sampling scheme and combines single-sided sawtooth wave PWM signal modulation, dead time compensation, closed-loop correction and other technologies, aiming to achieve high-precision current measurement and control by simplifying the current reconstruction process.

[0035] In step 202, the modulation wave is calculated based on the circuit's current reference value, current feedback value, and electrical angle value, and a count-down PWM sawtooth wave is constructed as the carrier wave.

[0036] The three-phase current reconfiguration circuit disclosed herein mainly consists of an inverter, a motor, a single-resistor sampling circuit, an analog-to-digital converter, and a microcontroller. The inverter can be a three-phase full-bridge inverter constructed using six insulated-gate bipolar transistors (IGBTs) or metal-oxide-semiconductor field-effect transistors (MOSFETs), which converts DC power into three-phase AC power to drive the motor.

[0037] This embodiment uses a three-phase motor as an example, but the method is also applicable to other types of AC motors such as induction motors. A single-resistor sampling circuit connects a sampling resistor in series on the DC bus side of the inverter to collect the bus current. The voltage signal across the sampling resistor is amplified and converted by an operational amplifier and an analog-to-digital converter before being input to the microcontroller (MCU). The microcontroller uses a digital signal processor (DSP) or other processor as its control core for voltage signal construction and three-phase current reconstruction.

[0038] In the specific operation of the three-phase current reconstruction method, the first step is to calculate the modulation wave and construct the carrier wave. The current reference value, current feedback value, and electrical angle value are obtained from the sensors of the motor control system. The current reference value is typically calculated based on the motor's control objectives, such as speed and torque. The current feedback value is obtained by processing the bus current sampled from a single resistor. The electrical angle value can be measured by sensors such as a rotary transformer or encoder. Based on these parameters, the required three-phase modulation wave can be calculated using algorithms such as PID control. Simultaneously, the timer inside the microcontroller generates a decrementing PWM sawtooth wave as the carrier wave; the frequency and amplitude of the carrier wave are set according to the requirements of the motor control system.

[0039] In step 204, the calculated modulated wave is compared with the first phase carrier to generate the first phase voltage.

[0040] Based on the calculated modulation wave and carrier wave, the first phase voltage is generated. The calculated first phase modulation wave is compared with the first phase carrier wave to generate a PWM signal for the first phase voltage, which is used to control the switching transistors of the first phase bridge arm in the three-phase inverter to turn on and off.

[0041] The MCU generates a single-sided sawtooth PWM signal using its internal counters and comparators. This PWM signal is generated through a down-counting control method to ensure accurate construction of the voltage in each phase. Specifically, the frequency of the PWM signal is in the range of 4kHz-20kHz, and the duty cycle of each cycle is dynamically adjusted according to the motor load conditions to meet the changing load current requirements. Based on this signal, the MCU generates a three-phase voltage signal through phase shifting based on the motor's electrical angle and reference current value, and uses this signal for current sampling.

[0042] In step 206, based on the first phase voltage and the time window length of the current sampling point of the test circuit, corresponding phase shifting processes are performed on the second phase carrier and the third phase carrier respectively to construct the second phase voltage and the third phase voltage.

[0043] During current sampling, the current sampling time window is set to a fixed range of 1-5 microseconds. This time window is precisely controlled by the MCU's timer to ensure that the current value can be stably acquired within each sampling window. The voltage phase shift corresponds to the length of the sampling window.

[0044] Specifically, the U-phase current is sampled by controlling the conduction of the MOSFETs in the upper U-phase, lower V-phase, and lower W-phase phases. The W-phase current is sampled by a combination of the upper U-phase, upper V-phase, and lower W-phase MOSFETs. The V-phase current is then reconstructed from the sampled U-phase and W-phase current values ​​using a formula. Specifically, the three-phase current reconstruction formula is: Iv + Iu + Iw = 0. Based on this three-phase current reconstruction formula, the third-phase current can be reconstructed after measuring the two-phase currents.

[0045] In step 208, the first phase current is determined in response to the first current sampling point time window and the second phase current is determined in response to the second current sampling point time window.

[0046] During the time window of the first current sampling point, the MCU controls the upper U-phase MOSFET, the lower V-phase MOSFET, and the lower W-phase MOSFET in the MOSFET transistor to turn on. Therefore, the current flowing through the sampling resistor is the U-phase current, and the current sampled at this time is the U-phase current Iu.

[0047] During the second current sampling time window, the MCU controls the upper U-phase MOSFET, the upper V-phase MOSFET, and the lower W-phase MOSFET to turn on. The current flowing through the sampling resistor is the negative of the W-phase current, and the sampled current is the W-phase current - Iw. Therefore, based on the reconstruction formula: Iv + Iu + Iw = 0, and given the determined U-phase and W-phase currents, the V-phase current can be reconstructed by the MCU: Iv = -Iu - Iw.

[0048] Based on the actual system sampling time requirements, the phase shift between the three-phase PWM modulation waves needs to be as small as possible while ensuring accurate sampling.

[0049] To ensure a reasonable sampling window and correct sampling due to phase shift, strict control of the duty cycles of the three phases U, V, and W is necessary during implementation; otherwise, errors in current acquisition and reconstruction will occur. This is easily guaranteed considering the switching delay and dead time of the switching transistors.

[0050] In step 210, the third phase current is reconstructed based on the determined first and second phase currents.

[0051] In a preferred embodiment, to address the impact of dead time on current sampling accuracy, the MCU can compensate by calculating the MOSFET turn-on delay and dead time. Based on the switching delay data of the switching transistors, the MCU corrects the sampling results in real time to compensate for the distortion of the current waveform caused by the dead time. Furthermore, the MCU dynamically adjusts the current measurement results using a closed-loop control algorithm based on factors such as motor load changes and operating environment, ensuring that the current sampling error remains within an acceptable range.

[0052] The MCU obtains the three-phase current signal through analog-to-digital converter (ADC) digital reconstruction, which is then used for further processing and control by the MCU. Based on the reconstructed three-phase current signal, the MCU generates control signals to adjust the duty cycle and phase of the PWM signal, thereby achieving precise control of the inverter drive system.

[0053] Figure 3 A schematic diagram of a circuit for reconstructing the three-phase current of a motor using a single resistor according to an embodiment of the present disclosure is shown. Figure 3As shown, the three-phase current reconstruction device includes, but is not limited to, M (i.e., MCU microcontroller unit), used to control the generation of PWM signals, current sampling triggering, and current reconstruction calculation, generating a single-sided sawtooth PWM signal and adjusting the current of each phase; a single sampling resistor, used to collect the U, V, and W three-phase currents, and the current sampling signal is converted into a digital signal by an analog-to-digital converter; an ADC (analog-to-digital converter sampler), used to convert the sampled signal into a digital signal and transmit it to the MCU; and six MOSFETs, with two MOSFETs corresponding to each phase motor winding, including an upper MOSFET and a lower MOSFET, used to drive the three-phase motor and perform current sampling.

[0054] Figure 4 A schematic diagram of voltage and current reconstructing the three-phase current of a motor using a single resistor according to an embodiment of this disclosure is shown. During current sampling, the MCU controls the turn-on timing of the MOSFETs in phases U, V, and W to ensure that the current of each phase is acquired and reconstructed within a suitable sampling time window. Figure 4 As shown, in the first sampling window (i.e., current sampling point time window 1), the MCU controls the upper U-phase transistor, lower V-phase transistor, and lower W-phase transistor to conduct in order to acquire the U-phase current; in the second sampling window (i.e., current sampling point time window 2), the MCU controls the upper U-phase transistor, upper V-phase transistor, and lower W-phase transistor to conduct in order to acquire the W-phase current; the V-phase current is reconstructed by the sum of the U-phase and W-phase currents, further ensuring the accuracy of the current measurement. It can be seen that the second-phase voltage is 15 degrees phase-shifted compared to the first-phase voltage, and the third-phase voltage is further 15 degrees phase-shifted compared to the second-phase voltage.

[0055] In a preferred embodiment, a current reconstruction method based on dead-time compensation technology is also provided, aiming to improve the accuracy of current reconstruction by correcting the current error caused by the turn-on delay of the switching transistor. Figure 4 As shown, the MCU also calculates the MOSFET's turn-on delay and its resulting dead time (circled part of the current sampling point) in real time based on the control logic and load status. By matching it with the sampling timing, the MCU performs error compensation on the sampled current data. During the current reconstruction process, the MCU corrects the current waveform based on real-time data to ensure the accuracy of the current measurement results. In addition, the MCU also performs real-time optimization for different load conditions and motor states through dynamic adjustment of the dead time, thereby maintaining the accuracy of current reconstruction in various operating environments.

[0056] In a preferred embodiment, a current sampling and reconstruction method based on asymmetric PWM modulation is also provided. This method, designed for situations with large load variations, optimizes the current sampling window by dynamically adjusting the rise and fall times of the PWM signal, thereby improving the accuracy of current reconstruction.

[0057] Specifically, under low load conditions, the rise and fall times of the PWM signal are longer, increasing the smoothness of the current waveform within the sampling window to reduce the impact of high-frequency noise. Under high load conditions, the rise and fall times of the PWM signal are shortened, increasing the duty cycle to improve the accuracy of current sampling. This asymmetric PWM modulation strategy can adapt to current variations under different load conditions, ensuring the accuracy of current reconstruction.

[0058] In addition, the MCU monitors the motor's load status in real time and dynamically adjusts the frequency and duty cycle of the PWM signal according to load changes, thereby ensuring the accuracy of current sampling and avoiding sampling errors caused by load fluctuations.

[0059] In a preferred embodiment, a method for current reconstruction using closed-loop correction technology is also provided. This method ensures accuracy during the current reconstruction process by correcting the deviation between sampled data and theoretical values ​​in real time.

[0060] In a preferred embodiment, a method for optimizing MOSFET turn-on control is also provided to ensure strict synchronization of the MOSFET turn-on timing during current sampling and reconstruction. In this embodiment, the MCU controls the turn-on timing of each phase MOSFET to ensure that each current sampling window is precisely aligned with the smooth region of the current waveform. Within the sampling window of the U-phase current, the MCU controls the upper U-phase MOSFET, the lower V-phase MOSFET, and the lower W-phase MOSFET to turn on; within the sampling window of the W-phase current, the MCU controls the upper U-phase MOSFET, the upper V-phase MOSFET, and the lower W-phase MOSFET to turn on. The V-phase current is derived through a formula to ensure that the reconstructed three-phase current signal is error-free. Furthermore, to improve the accuracy of current measurement, the MCU performs real-time correction after each sampling to dynamically compensate for distortions in the current waveform, ensuring the accuracy and reliability of the current reconstruction.

[0061] Utilizing the above techniques, this solution employs single-resistor sampling, resulting in a small PCB footprint, fewer required components, and the lowest system cost. Furthermore, compared to existing technologies, this solution features a fixed sampling window time, eliminating the need for window shifting. The first sampling window represents the U-phase current, and the second represents the W-phase current, with fixed meanings requiring no MCU logic judgment. A single mathematical operation is all that's needed to reconstruct the V-phase current. The software code implementing the reconstruction algorithm is minimal, with extremely short computation time, significantly reducing the demand on MCU computing resources.

[0062] Figure 5 A schematic block diagram of an example electronic device 500 that can be used to implement embodiments of the present disclosure is shown. For example, such as Figure 1The computing device 110 shown can be implemented by an electronic device 500. As shown, the electronic device 500 includes a central processing unit (CPU) 501, which can perform various appropriate actions and processes according to computer program instructions stored in read-only memory (ROM) 502 or loaded from storage unit 508 into random access memory (RAM) 503. The random access memory 503 can also store various programs and data required for the operation of the electronic device 500. The CPU 501, ROM 502, and RAM 503 are interconnected via a bus 504. An input / output (I / O) interface 505 is also connected to the bus 504.

[0063] Multiple components in electronic device 500 are connected to input / output interface 505, including: input unit 506, such as keyboard, mouse, microphone, etc.; output unit 507, such as various types of monitors, speakers, etc.; storage unit 508, such as disk, optical disk, etc.; and communication unit 509, such as network card, modem, wireless transceiver, etc. Communication unit 509 allows device 500 to exchange information / data with other devices through computer networks such as the Internet and / or various telecommunications networks.

[0064] The various processes and procedures described above, such as methods 200 and 400, may be executed by the central processing unit 501. For example, in some embodiments, methods 200, 400, and 500 may be implemented as computer software programs tangibly contained in a machine-readable medium, such as storage unit 508. In some embodiments, part or all of the computer program may be loaded and / or installed on device 500 via read-only memory 502 and / or communication unit 509. When the computer program is loaded into random access memory 503 and executed by the central processing unit 501, one or more actions of methods 200 and 400 described above may be performed.

[0065] This disclosure relates to methods, apparatus, systems, electronic devices, computer-readable storage media, and / or computer program products. A computer program product may include computer-readable program instructions for performing various aspects of this disclosure.

[0066] Computer-readable storage media can be tangible devices capable of holding and storing instructions for use by an instruction execution device. Computer-readable storage media can be, for example—but not limited to—electrical storage devices, magnetic storage devices, optical storage devices, electromagnetic storage devices, semiconductor storage devices, or any suitable combination thereof. More specific examples (a non-exhaustive list) of computer-readable storage media include: portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), static random access memory (SRAM), portable compact disc read-only memory (CD-ROM), digital multifunction disc (DVD), memory sticks, floppy disks, mechanical encoding devices, such as punch cards or recessed protrusions storing instructions thereon, and any suitable combination thereof. The computer-readable storage media used herein are not to be construed as transient signals themselves, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through waveguides or other transmission media (e.g., light pulses through fiber optic cables), or electrical signals transmitted through wires.

[0067] The computer-readable program instructions described herein can be downloaded from computer-readable storage media to various computing / processing devices, or downloaded via a network, such as the Internet, local area network, wide area network, and / or wireless network, to an external computer or external storage device. The network may include copper transmission cables, fiber optic transmission, wireless transmission, routers, firewalls, switches, gateway computers, and / or edge computing devices. A network adapter card or network interface in each computing / processing device receives the computer-readable program instructions from the network and forwards them to computer-readable storage media within the respective computing / processing device.

[0068] Computer program instructions used to perform the operations of this disclosure may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, status setting data, or source code or object code written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Smalltalk, C++, etc., and conventional procedural programming languages ​​such as the "C" language or similar programming languages. The computer-readable program instructions may execute entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving a remote computer, the remote computer may be connected to the user's computer via any type of network—including a local area network (LAN) or a wide area network (WAN)—or may be connected to an external computer (e.g., via the Internet using an Internet service provider). In some embodiments, electronic circuitry, such as programmable logic circuitry, field-programmable gate arrays (FPGAs), or programmable logic arrays (PLAs), is personalized by utilizing the status information of the computer-readable program instructions to implement various aspects of this disclosure.

[0069] Various aspects of this disclosure are described herein with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this disclosure. It should be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer-readable program instructions.

[0070] These computer-readable program instructions can be provided to a processing unit of a general-purpose computer, a special-purpose computer, or other programmable data processing apparatus to produce a machine such that, when executed by the processing unit of the computer or other programmable data processing apparatus, they create means for implementing the functions / actions specified in one or more blocks of the flowchart and / or block diagram. These computer-readable program instructions can also be stored in a computer-readable storage medium that causes a computer, programmable data processing apparatus, and / or other device to operate in a particular manner. Thus, the computer-readable medium storing the instructions comprises an article of manufacture that includes instructions for implementing aspects of the functions / actions specified in one or more blocks of the flowchart and / or block diagram.

[0071] Computer-readable program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other device to cause a series of operational steps to be performed on the computer, other programmable data processing apparatus, or other device to produce a computer-implemented process, thereby causing the instructions executed on the computer, other programmable data processing apparatus, or other device to perform the functions / actions specified in one or more boxes of a flowchart and / or block diagram.

[0072] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present disclosure. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of an instruction, which contains one or more executable instructions for implementing a specified logical function. In some alternative implementations, the functions marked in the blocks may occur in a different order than those marked in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, may be implemented using a dedicated hardware-based system that performs the specified function or action, or using a combination of dedicated hardware and computer instructions.

[0073] Those skilled in the art will understand that the present invention is not limited to the embodiments described above, and that the invention may be implemented in many other forms without departing from its spirit and scope. Therefore, the examples and embodiments shown are to be considered illustrative rather than restrictive, and the invention may encompass various modifications and substitutions without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. A method for reconstructing the three-phase current of a motor using a single resistor, characterized in that, The method includes: The modulation wave is calculated based on the circuit's current reference value, current feedback value, and electrical angle value, and a count-down PWM sawtooth wave is constructed as the carrier wave. The calculated modulated wave is compared with the first phase carrier to generate the first phase voltage; Based on the first phase voltage, and according to the time window length of the current sampling point of the test circuit, corresponding phase shifting processes are performed on the second phase carrier and the third phase carrier respectively, thereby constructing the second phase voltage and the third phase voltage. The phase shift amount of the voltage after the phase shifting process corresponds to the time window length of the current sampling point. The first phase current is determined in response to a first current sampling point time window, and the second phase current is determined in response to a second current sampling point time window; and Based on the determined first and second phase currents, the third phase current is reconstructed.

2. The method according to claim 1, characterized in that, Determining the first phase current in response to a first current sampling point time window and determining the second phase current in response to a second current sampling point time window includes: The trigger signal is generated by the microcontroller's timer to determine the start time of the current sampling point time window; At the beginning of the time window for the first current sampling point, the sampling of the first phase current is triggered; and Based on a fixed phase shift, the second phase current sampling is triggered within the second current sampling point time window to ensure that the current sampling point time windows do not overlap.

3. The method according to claim 1, characterized in that, The method further includes: The microcontroller calculates the impact of dead time on current measurement based on preset dead time parameters; During the reconstruction of the third phase current, the measured current value is corrected in real time based on the dead time offset within the time window of the first current sampling point and the time window of the second current sampling point. Dynamic compensation is performed for current errors during dead time based on different phase and load conditions; and The dynamically compensated current value is used for further current reconstruction to improve the accuracy of current reconstruction.

4. The method according to claim 1, characterized in that, The method further includes: Calculate the deviations between the measured and theoretical values ​​of the currently determined first-phase current and second-phase current; Based on the circuit's load conditions and motor parameters, the PWM sawtooth waveform is adjusted to reduce deviation; and The corrected current measurement value is fed back to the microcontroller unit for use in the next PWM modulation.

5. The method according to claim 1, characterized in that, The reconstruction of the third phase current based on the determined first and second phase currents includes: Within the current sampling time window, the microcontroller optimizes the sampling time by controlling the phase offset of the PWM signal to ensure that the current sampling time window falls within the stable region of the current waveform. During current reconstruction calculations, the microcontroller adjusts the sampling time to match the dead time based on the current change trend within the time window of the current sampling point, in order to eliminate current waveform distortion caused by the dead time; and The microcontroller unit monitors load changes in real time and dynamically adjusts the dead-zone compensation strategy to adapt to different load conditions.

6. The method according to any one of claims 1-5, characterized in that, The sampling windows for the first phase current and the second phase current are set within the range of 1-5 microseconds, and a fixed phase shift is used to ensure the relative timing stability of the sampling window and reduce the impact of PWM dead time.

7. The method according to claim 6, characterized in that, The single-sided sawtooth PWM signal is generated by an MCU counter and comparator to ensure accurate timing of PWM waveform modulation and optimize the position of the current sampling window based on the PWM waveform.

8. The method according to claim 1, characterized in that, The first phase is U phase, the second phase is V phase, and the third phase is W phase.

9. A current reconfiguration device for a motor inverter, wherein the current reconfiguration device reconfigures the three-phase current using the method described in any one of claims 1-7, characterized in that, include: The microcontroller unit is configured to generate and control a single-sided sawtooth PWM signal, and to perform phase-shift modulation to match the current sampling window, perform current sampling, and reconstruct the three-phase current. A single resistor, configured for current sampling, is connected to the common circuit of the lower bridge arm of the inverter; The sampling analog-to-digital converter is configured to convert the current signal sampled by a single resistor into a voltage signal, convert the sampled signal into a digital signal, and input the converted digital signal into a microcontroller unit. A MOSFET transistor, comprising an upper transistor and a lower transistor, configured to drive a three-phase motor.

10. The device according to claim 9, characterized in that, The conduction mode of the MOSFET transistor corresponds to the current sampling time window, specifically as follows: In the first sampling window, the microcontroller controls the MOSFET to turn on the upper U-phase MOSFET, the lower V-phase MOSFET, and the lower W-phase MOSFET, so that the current flowing through the single resistor corresponds to the U-phase current; In the second sampling window, the microcontroller controls the MOSFET to turn on the upper U-phase MOSFET, the upper V-phase MOSFET, and the lower W-phase MOSFET, so that the current flowing through the single resistor corresponds to the negative value of the W-phase current. as well as Based on the measured currents of phases U and W, the microcontroller calculates the phase V current using the three-phase current reconstruction method to complete the reconstruction of the three-phase current.

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