Method and device for reconstructing three-phase current of motor through single resistor and medium

Abstract

The embodiment of the invention relates to a method and equipment for reconstructing a three-phase current of a motor by a single resistor. The method comprises the following steps: calculating a modulation wave based on a current reference value, a current feedback value and an electrical angle value of a circuit, and constructing a subcount PWM sawtooth wave as a carrier wave; comparing the calculated modulated wave with a first phase carrier to generate a first phase voltage; taking the first phase voltage as a reference, respectively executing corresponding phase shift processing on a second phase carrier and a third phase carrier based on the time window length of a current sampling point of the test circuit so as to construct a second phase voltage and a third phase voltage; determining a first phase current in response to the first current sampling point time window and a second phase current in response to the second current sampling point time window; and reconstructing a third phase current based on the determined first phase current and second phase current.

Description

Technical Field

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

[0002] In order to achieve high-performance motor control, it is usually necessary to detect the current of each phase winding. Through real-time current detection, a PWM drive signal is output to control the switching devices of the three-phase inverter. The phase current size can usually be obtained by resistor voltage division. Considering the cost reduction, only two current sensors can be used to reconstruct the three-phase current size, because the sum of the three-phase current must be zero under normal working conditions (i.e., Ia+Ib+Ic=0). This method can save one current sensor.

[0003] The current solution of using magnetic or photoelectric current sensors to obtain and reconstruct the three-phase current of the motor has the problems of high cost and large product size. The method of using three resistors to shunt the lower bridge arm requires three sets of identical sampling hardware circuits, but the inconsistency of hardware parameters will lead to the accuracy of the motor phase current reconstruction.

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

[0005] In order to obtain the output three-phase current, the inverter circuit in the prior art can adopt a variety of current sampling schemes, including direct sampling of the output phase line, three-resistance or two-resistance sampling of the lower bridge arm, and single-resistance sampling. Because the single-resistance sampling scheme has a simple circuit, occupies a small PCB area, and has a low total cost, it has been widely used.

[0006] However, the single resistor sampling scheme requires a complex software algorithm to reconstruct the three-phase output current of the inverter. For example, the current reconstruction method proposed in the patents such as CN115642852A, CN115776261A, and CN118707184A in the prior art generally adopts a seven-segment SVPWM (space vector pulse width modulation) wave generation method with increase and decrease counts, which requires a large amount of software code and complex mathematical and logical operations. What is more complicated is that when the output voltage is low, the current sampling window is too small, which will cause sampling failure, and the sampling window needs to be shifted to leave enough sampling window time. This further increases the complexity of the current reconstruction algorithm.

[0007] Therefore, a method is needed to reconstruct the three-phase current by only down-counting or performing a translation process on the sampling window. Summary of the invention

[0008] In response to the above problems, the present disclosure provides a method for reconstructing the three-phase current of a motor using a single resistor, the method comprising: calculating a modulation wave based on a current reference value, a current feedback value and an electrical angle value of a circuit and constructing a PWM sawtooth wave with a down count as a carrier; comparing the calculated modulation wave with a first-phase carrier to generate a first-phase voltage; taking the first-phase voltage as a reference and based on a current sampling point time window length of a test circuit, performing corresponding phase shift processing on a second-phase carrier and a third-phase carrier respectively, thereby constructing 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 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 the first current sampling point time window and determining the second phase current in response to the second current sampling point time window includes: generating a trigger signal through a micro control unit timer to determine the start time of the current sampling point time window; triggering the sampling of the first phase current at the start time of the first current sampling point time window; and triggering the sampling of the second phase current in the second current sampling point time window according to a fixed phase shift amount, ensuring that the current sampling point time windows do not overlap.

[0010] In one embodiment, the method further includes: the microcontroller unit calculates the influence of the dead time on the current measurement according to the preset dead time parameters; when reconstructing the third phase current, based on the dead time offset within the first current sampling point time window and the second current sampling point time window, performs real-time correction on the measured current value; according to different phases and load conditions, dynamically compensates for the current error of the dead time; and uses the dynamically compensated current value for further current reconstruction to improve the current reconstruction accuracy.

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

[0012] In one embodiment, reconstructing the third phase current based on the determined first phase current and second phase current includes: within the current sampling point time window, the micro control unit optimizes the sampling time point by controlling the phase offset of the PWM signal to ensure that the current sampling point time window falls in the stable area of ​​the current waveform; when calculating the current reconstruction, the micro control unit adjusts the sampling time to match the dead time based on the current change trend within the current sampling point time window to eliminate the current waveform distortion caused by the dead time; and the micro control unit monitors the 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 windows of the first phase current and the second phase current are set within a range of 1-5 microseconds and a fixed phase shift is used to ensure the relative timing stability of the sampling windows and reduce the impact of the PWM dead time.

[0014] In one embodiment, the single-sided sawtooth wave PWM signal is generated by an MCU counter and a comparator to ensure the timing of the PWM waveform modulation is accurate and 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 reconstruction device for a three-phase motor inverter is provided, wherein the current reconstruction device reconstructs the three-phase current using the above method, and includes: a microcontroller unit MCU, configured to generate and control a single-sided sawtooth wave PWM signal, and perform phase shift modulation to cooperate with a current sampling window, perform current sampling and three-phase current reconstruction; a single resistor, configured for current sampling, connected to a common loop of a 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 into the MCU; a MOSFET transistor, wherein the MOSFET transistor includes an upper tube and a lower tube, and is 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 U-phase upper tube, the V-phase lower tube, and the W-phase lower tube, 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 U-phase upper tube, the V-phase upper tube, and the W-phase lower tube, 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 through the three-phase current reconstruction method to complete the reconstruction of the three-phase current.

[0018] According to a third aspect of the present disclosure, a computing device is provided, comprising: at least one processor; and a memory communicatively connected to the at least one processor; the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the method of the first aspect of the present disclosure.

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

[0020] It should be understood that the content described in this section is not intended to identify the key or important features of the embodiments of the present disclosure, nor is it intended to limit the scope of the present disclosure. Other features of the present disclosure will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The above and other features, advantages and aspects of the embodiments of the present disclosure will become more apparent with reference to the following detailed description in conjunction with the accompanying drawings. In the accompanying drawings, the same or similar reference numerals represent the same or similar elements.

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

[0023] Figure 2 A flow chart 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.

[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 showing voltage and current of a motor's three-phase current reconstructed by a single resistor according to an embodiment of the present disclosure is shown.

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

[0027] The following is a description of exemplary embodiments of the present disclosure in conjunction with the accompanying drawings, including various details of the embodiments of the present disclosure to facilitate understanding, which should be considered as merely exemplary. Therefore, it should be recognized by those of ordinary skill in the art that various changes and modifications may be made to the embodiments described herein without departing from the scope and spirit of the present disclosure. Similarly, for the sake of clarity and conciseness, descriptions of well-known functions and structures are omitted in the following description.

[0028] As used herein, the term "including" and its variations mean open inclusion, i.e., "including but not limited to". Unless otherwise stated, the term "or" means "and / or". The term "based on" means "based at least in part on". The terms "an example embodiment" and "an 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 FIG. 1 is a schematic diagram of a system 100 for implementing a method for reconstructing three-phase current of a motor using a single resistor according to an embodiment of the present disclosure. Figure 1 As shown in FIG. 1 , the system 100 includes a computing device 110 , a motor three-phase current reconstruction device 130 , and a network 140 . The computing device 110 and the motor three-phase current reconstruction device 130 can exchange data through the network 140 .

[0030] The motor three-phase current reconstruction device 130, for example, can perform functions such as three-phase current reconstruction for the inverter motor. The motor three-phase current reconstruction device 130 can also send the determined reconstructed current to the computing device 110. The motor three-phase current reconstruction device 130 can have one or more processing units, including dedicated processing units such as MCU, GPU, FPGA and ASIC, and general processing units such as CPU, 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 smart watches and activity tracker devices) that can perform Chinese data reading and modification.

[0031] Regarding the computing device 110, it is used, for example, to receive voltage compensation data from the motor three-phase current reconstruction device 130 via the network 140. The computing device 110 may have one or more processing units, including dedicated processing units such as GPU, FPGA and ASIC, and general processing units such as CPU. In addition, one or more virtual machines may also be running on each computing device 110. In some embodiments, the computing device 110 and the motor three-phase current reconstruction device 130 may be integrated together or may be separately arranged.

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

[0033] Figure 2FIG. 2 is a flow chart showing a method 200 for reconstructing three-phase current of a motor using a single resistor according to an embodiment of the present disclosure. The method 200 may be performed as follows: Figure 1 The computing device 110 shown may also be executed in Figure 5 The method 200 is executed at the electronic device 500. It should be understood that the method 200 may further include additional blocks not shown and / or may omit the blocks shown, and the scope of the present disclosure is not limited in this respect.

[0034] The present embodiment provides a current reconstruction method and device for a three-phase motor inverter. The method adopts a single-resistance current sampling scheme and combines single-sided sawtooth 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, a modulation wave is calculated based on a current reference value, a current feedback value and an electrical angle value of the circuit and a down-counting PWM sawtooth wave is constructed as a carrier.

[0036] The three-phase current reconstruction circuit disclosed in the present invention is mainly composed of an inverter, a motor, a single resistor sampling circuit, an analog-to-digital converter and a microcontroller. The inverter can use six insulated gate bipolar transistors (IGBTs) or metal-oxide-semiconductor field-effect transistors (MOSFETs) to build a three-phase full-bridge inverter, which converts a DC power supply into a three-phase AC power supply to drive the motor to operate.

[0037] This embodiment is described using 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 is connected in series with a sampling resistor on the DC bus side of the inverter to collect the bus current. The voltage signal at both ends of the sampling resistor is amplified and converted by an operational amplifier and an analog-to-digital converter, and then input to the microcontroller MCU. The microcontroller uses a digital signal processor (DSP) or other processor as the control core, voltage signal construction and three-phase current reconstruction.

[0038] In the specific operation of the three-phase current reconstruction method, the modulation wave is first calculated and the carrier is constructed. The current reference value, current feedback value and electrical angle value of the circuit are obtained through the sensor of the motor control system. The current reference value can usually be calculated based on the control target of the motor, such as speed, torque and other data. The current feedback value is obtained after processing the bus current obtained by single resistor sampling. The electrical angle value can be measured by sensors such as rotary transformers or encoders. Based on these parameters, the required three-phase modulation wave can be calculated using algorithms such as PID control. At the same time, the timer inside the microcontroller generates a PWM sawtooth wave with a countdown as the carrier, and the frequency and amplitude of the carrier are set according to the requirements of the motor control system.

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

[0040] Based on the calculated modulation wave and carrier, a first phase voltage is generated. The calculated first phase modulation wave is compared with the first phase carrier to generate a PWM signal of the first phase voltage, which is used to control the switching tube 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 through its internal counter and comparator. The PWM signal is generated by down-counting control to ensure the accurate construction of each phase voltage. Specifically, the frequency of the PWM signal is in the range of 4k-20kHz, and the duty cycle of each cycle is dynamically adjusted according to the motor load conditions to meet the changing requirements of the load current. Based on this signal, the MCU generates a three-phase voltage signal through phase shift processing according to the electrical angle and reference current value of the motor, and uses it for current sampling.

[0042] In step 206, taking the first phase voltage as a reference and based on the time window length of the current sampling point of the test circuit, corresponding phase shift processing is performed on the second phase carrier and the third phase carrier respectively, so as to construct the second phase voltage and the third phase voltage.

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

[0044] Specifically, the U-phase current is sampled by controlling the MOSFETs of the U-phase upper tube, the V-phase lower tube, and the W-phase lower tube to be turned on, the W-phase current is sampled by the combined control of the U-phase upper tube, the V-phase upper tube, and the W-phase lower tube, and the V-phase current is reconstructed according to the formula by the current sampling values ​​of the U-phase and W-phase. Specifically, the reconstruction formula of the three-phase current is: Iv+Iu+Iw=0. The reconstruction formula based on the three-phase current can reconstruct the third-phase current after measuring the two-phase current.

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

[0046] In the first current sampling point time window, the MCU controls the U-phase MOSFET upper tube, the V-phase MOSFET lower tube, and the W-phase MOSFET lower tube in the MOSFET transistor to be turned on, so 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] In the second current sampling point time window, the MCU controls the U-phase MOSFET upper tube, V-phase MOSFET upper tube, and W-phase MOSFET lower tube in the MOSFET transistor to turn on, and the current flowing through the sampling resistor is the negative value of the W-phase current. At this time, the sampled current is the W-phase current -Iw. Therefore, based on the reconstruction formula: Iv+Iu+Iw=0, and the U-phase current and W-phase current have been determined, the V-phase current can be reconstructed by the MCU: Iv=-Iu-Iw.

[0048] According to the requirements of the actual system sampling time, the phase shift between the three-phase PWM modulation waves needs to be as small as possible while meeting the condition of accurate sampling.

[0049] In order to ensure that the sampling window generated by the phase shift is reasonable and the sampling is correct, it is necessary to strictly control the duty cycle of the three phases U, V, and W during the specific implementation, otherwise current collection and reconstruction errors will occur. This is easy to ensure based on the switching delay and dead time of the switch tube.

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

[0051] In a preferred embodiment, in order to solve the influence of dead time on the current sampling accuracy, the MCU can compensate by calculating the MOSFET turn-on delay and dead time. According to the switch delay data of the switch tube, the MCU compensates for the distortion of the current waveform caused by the dead time by correcting the sampling results in real time. In addition, the MCU dynamically adjusts the current measurement results through a closed-loop control algorithm according to factors such as motor load changes and working environment to ensure that the current sampling error is within an acceptable range.

[0052] The MCU uses the analog-to-digital converter (ADC) to digitize and reconstruct the three-phase current signal for further processing and control by the MCU. The MCU generates a control signal based on the reconstructed three-phase current signal to adjust the duty cycle and phase of the PWM signal, thereby achieving precise control of the inverter drive system.

[0053] Figure 3 FIG. 1 is 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. Figure 3As shown, the three-phase current reconstruction device includes but is not limited to M (i.e., MCU microcontroller unit), which is used to control the generation of PWM signals, current sampling triggering and current reconstruction calculation, generate a single-sided sawtooth PWM signal, and adjust the current of each phase; a single sampling resistor, which is used to collect U, V, and W three-phase currents, and the current sampling signal is converted into a digital signal through an analog-to-digital converter; an ADC (ADC analog-to-digital converter sampler), which is used to convert the sampling signal into a digital signal and transmit it to the MCU; six MOSFETs, two MOSFETs corresponding to each phase motor winding, including an upper tube and a lower tube, which are used to drive the three-phase motor and perform current sampling.

[0054] Figure 4 The schematic diagram of the voltage and current of the three-phase current of the motor reconstructed by a single resistor according to an embodiment of the present disclosure is shown. During the current sampling process, the MCU controls the conduction timing of the MOSFETs of the three phases U, V, and W to ensure that the current of each phase is collected and reconstructed within the appropriate sampling time window. Figure 4 As shown, in the first sampling window (i.e., current sampling point time window 1), the MCU controls the U-phase upper tube, V-phase lower tube, and W-phase lower tube to be turned on to collect the U-phase current; in the second sampling window (i.e., current sampling point time window 2), the MCU controls the U-phase upper tube, V-phase upper tube, and W-phase lower tube to be turned on to collect the W-phase current; the V-phase current is reconstructed by the sum of the U and W-phase currents to further ensure the accuracy of the current measurement. It can be seen that the second-phase voltage is 15 degrees shifted compared to the first-phase voltage, and the third-phase voltage is another 15 degrees shifted compared to the second-phase voltage.

[0055] In a preferred embodiment, a current reconstruction method based on dead zone compensation technology is also provided, which aims to improve the accuracy of current reconstruction by correcting the current error caused by the turn-on delay of the switch tube. Figure 4 As shown in the figure, the MCU also calculates the turn-on delay of the MOSFET and the dead time caused by it (the circled part of the current sampling point) in real time according to the control logic and load status. By matching the sampling timing, the MCU compensates the error of the sampled current data. During the current reconstruction process, the MCU corrects the current waveform in combination with real-time data to ensure the accuracy of the current measurement results. In addition, the MCU also optimizes in real time for different load conditions and motor states through dynamic adjustment of the dead time, thereby maintaining the accuracy of current reconstruction in various working environments.

[0056] In a preferred embodiment, a current sampling and reconstruction method based on asymmetric PWM modulation is also provided. The method optimizes the current sampling window by dynamically adjusting the rise and fall time of the PWM signal in the case of large load changes, 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 stability 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 changes under different load conditions and ensure the accuracy of current reconstruction.

[0058] In addition, the MCU monitors the load status of the motor 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 a closed-loop correction technique is also provided. The method ensures the accuracy of the current reconstruction process by correcting the deviation between the sampled data and the theoretical value in real time.

[0060] In a preferred embodiment, a method for optimizing MOSFET conduction control is also provided to ensure that the current sampling and the conduction timing of the MOSFET during the reconstruction process are strictly synchronized. In this embodiment, the MCU ensures that each current sampling window is accurately aligned with the stable area of ​​the current waveform by controlling the conduction timing of each phase MOSFET. In the sampling window of the U-phase current, the MCU controls the conduction of the U-phase upper tube, the V-phase lower tube, and the W-phase lower tube; in the sampling window of the W-phase current, the MCU controls the conduction of the U-phase upper tube, the V-phase upper tube, and the W-phase lower tube. The V-phase current is derived by formula to ensure that the reconstructed three-phase current signal is error-free. In addition, in order to improve the current measurement accuracy, the MCU performs real-time correction after each sampling, dynamically compensates for the distortion in the current waveform, and ensures the accuracy and reliability of current reconstruction.

[0061] By using the above technical means, due to the use of single resistor sampling, the equipment occupies a small PCB area, requires a small number of components, and has the lowest system cost. At the same time, compared with the existing technology, this solution has a fixed sampling window time, and there is no need to translate the sampling window. The first sampling window is the U phase current, and the second sampling window is the W phase current. The meaning is fixed and no MCU logic judgment is required. Finally, a mathematical operation is performed to reconstruct the V phase current. The amount of software code to implement the reconstruction algorithm is extremely small, and the operation time is extremely short, which greatly reduces the occupation of MCU computing resources.

[0062] Figure 5 Schematic block diagram of an example electronic device 500 that can be used to implement an embodiment of the present disclosure is shown. 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 a read-only memory (ROM) 502 or computer program instructions loaded from a storage unit 508 to a random access memory (RAM) 503. In the random access memory 503, various programs and data required for the operation of the electronic device 500 can also be stored. The central processing unit 501, the read-only memory 502, and the random access memory 503 are connected to each other via a bus 504. An input / output (I / O) interface 505 is also connected to the bus 504.

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

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

[0065] The present disclosure relates to methods, apparatuses, systems, electronic devices, computer-readable storage media and / or computer program products. The computer program products may include computer-readable program instructions for executing various aspects of the present disclosure.

[0066] A computer-readable storage medium may be a tangible device that can hold and store instructions used by an instruction execution device. A computer-readable storage medium may be, for example, but not limited to, an electrical storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination of the foregoing. More specific examples of computer-readable storage media (a non-exhaustive list) include: a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), a static random access memory (SRAM), a portable compact disk read-only memory (CD-ROM), a digital versatile disk (DVD), a memory stick, a floppy disk, a mechanical encoding device, such as a punch card or a raised structure in a groove on which instructions are stored, and any suitable combination of the foregoing. As used herein, a computer-readable storage medium is not to be interpreted as a transient signal per se, such as a radio wave or other freely propagating electromagnetic wave, an electromagnetic wave propagating through a waveguide or other transmission medium (e.g., a light pulse through a fiber optic cable), or an electrical signal transmitted through a wire.

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

[0068] The computer program instructions for performing the operation of the present disclosure may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-related instructions, microcode, firmware instructions, state 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 "C" language or similar programming languages. Computer-readable program instructions may be executed entirely on a user's computer, partially on a user's computer, as an independent software package, partially on a user's computer, partially on a remote computer, or completely on a remote computer or server. In the case of 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., using an Internet service provider to connect via the Internet). In some embodiments, an electronic circuit, such as a programmable logic circuit, a field programmable gate array (FPGA), or a programmable logic array (PLA), may be customized by utilizing the state information of the computer-readable program instructions, and the electronic circuit may execute the computer-readable program instructions, thereby realizing various aspects of the present disclosure.

[0069] Various aspects of the present disclosure are described herein with reference to the flowcharts and / or block diagrams of the methods, devices (systems) and computer program products according to the embodiments of the present disclosure. It should be understood that each box in the flowchart and / or block diagram and the combination of each box in the flowchart and / or block diagram 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 device, thereby producing a machine, so that when these instructions are executed by the processing unit of the computer or other programmable data processing device, a device that implements the functions / actions specified in one or more boxes in the flowchart and / or block diagram is generated. These computer-readable program instructions can also be stored in a computer-readable storage medium, and these instructions cause the computer, programmable data processing device, and / or other equipment to work in a specific manner, so that the computer-readable medium storing the instructions includes a manufactured product, which includes instructions for implementing various aspects of the functions / actions specified in one or more boxes in 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 so that a series of operating steps are 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 implement the functions / actions specified in one or more boxes in the flowchart and / or block diagram.

[0072] The flow chart and block diagram in the accompanying drawings show the possible architecture, function and operation of the system, method and computer program product according to multiple embodiments of the present disclosure. In this regard, each square box in the flow chart or block diagram can represent a part of a module, program segment or instruction, and a part of a module, program segment or instruction includes one or more executable instructions for realizing the specified logical function. In some alternative implementations, the function marked in the square box can also occur in a sequence different from that marked in the accompanying drawings. For example, two continuous square boxes can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each square box in the block diagram and / or flow chart, and the combination of the square boxes in the block diagram and / or flow chart can be implemented with a dedicated hardware-based system that performs the specified function or action, or can be implemented with a combination of special hardware and computer instructions.

[0073] Those skilled in the art should understand that the present invention is not limited to the above-mentioned embodiments, and the present invention can be implemented in many other forms without departing from its purpose and scope. Therefore, the examples and embodiments shown are regarded as illustrative rather than restrictive, and the present invention may cover various modifications and substitutions without departing from the spirit and scope of the present invention as defined in 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 comprises: Calculate the modulation wave based on the current reference value, current feedback value and electrical angle value of the circuit and construct a PWM sawtooth wave with down counting as a carrier wave; Comparing the calculated modulation wave with the first phase carrier wave to generate a first phase voltage; Taking the first phase voltage as a reference and based on the time window length of the current sampling point of the test circuit, respectively performing corresponding phase shift processing on the second phase carrier and the third phase carrier, thereby constructing the second phase voltage and the 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 Based on the determined first phase current and second phase current, a third phase current is reconstructed.

2. The method according to claim 1, characterized in that 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 includes: A trigger signal is generated by a microcontroller unit timer to determine the start time of the current sampling point time window; At the beginning of the first current sampling point time window, triggering sampling of the first phase current; and According to the fixed phase shift amount, the second phase current sampling is triggered in the second current sampling point time window to ensure that the current sampling point time windows do not overlap with each other.

3. The method according to claim 1, characterized in that The method further comprises: The microcontroller unit calculates the effect of the dead time on the current measurement according to the preset dead time parameters; When reconstructing the third phase current, performing real-time correction on the measured current value based on the dead time offset within the first current sampling point time window and the second current sampling point time window; Dynamically compensate for current errors during dead time according to different phase and load conditions; and The current value after dynamic compensation is used for further current reconstruction to improve the current reconstruction accuracy.

4. The method according to claim 1, characterized in that: The method further comprises: Calculate the deviation between the measured value of the first phase current and the second phase current currently determined and the theoretical value; Based on the circuit's load conditions and motor parameters, adjust the PWM sawtooth wave 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: Reconstructing the third-phase current based on the determined first-phase current and second-phase current includes: In the current sampling point time window, the microcontroller unit optimizes the sampling time point by controlling the phase offset of the PWM signal to ensure that the current sampling point time window falls in the stable area of ​​the current waveform; During current reconstruction calculation, the microcontroller unit adjusts the sampling time to match the dead time based on the current change trend within the time window of the current sampling point to eliminate the 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 to 5, characterized in that The sampling windows of the first phase current and the second phase current are set within the range of 1-5 microseconds, and a fixed phase shift is adopted to ensure the relative timing stability of the sampling windows and reduce the influence of the PWM dead time.

7. The method according to claim 6, characterized in that The unilateral sawtooth wave PWM signal is generated by an MCU counter and a comparator to ensure the timing of the PWM waveform modulation is accurate 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 the U phase, the second phase is the V phase, and the third phase is the W phase.

9. A current reconstruction device for a motor inverter, the current reconstruction device reconstructing three-phase current using the method of claims 1-7, characterized in that: include: A micro control unit configured to generate and control a single-sided sawtooth wave PWM signal, and perform phase shift modulation to match a current sampling window, perform current sampling, and perform three-phase current reconstruction; A single resistor, configured for current sampling, connected to the common loop of the lower bridge arm of the inverter; A sampling analog-to-digital converter is configured to convert the current signal sampled by the single resistor into a voltage signal, convert the current signal sampled by the sampling analog-to-digital converter into a digital signal and input the converted digital signal into a microcontroller unit; A MOSFET transistor includes an upper tube and a lower tube, and is 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: In the first sampling window, the microcontroller controls the MOSFET to turn on the upper tube of the U phase, the lower tube of the V phase, and the lower tube of the W phase, 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 tube of the U phase, the upper tube of the V phase, and the lower tube of the W phase, 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 the U-phase and W-phase, the microcontroller unit calculates the V-phase current through a three-phase current reconstruction method to complete the reconstruction of the three-phase current.

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