Motor control method based on single-resistor sampling, controller and electrical equipment

Abstract

The application relates to a motor control method based on single-resistance sampling, a controller and an electrical device. The method generates PWM signals by adopting a five-segment space vector modulation strategy when the motor is in a starting stage, and generates PWM signals by adopting a seven-segment space vector modulation strategy when the motor is in a running stage. Therefore, the method adopts the five-segment modulation strategy in the starting stage, so that the sampling time window is directly equal to the complete action time of the non-zero voltage vector, the width is doubled, sufficient establishment time is provided for the sampling circuit, switching noise interference is effectively resisted, and the reliability of current sampling in the heavy load and low speed starting stage is ensured. In the running stage, the seven-segment modulation is switched to, the zero vectors are symmetrically distributed, the current harmonic is small, the electromagnetic noise is low, the high-frequency control performance is good, and the silence, low vibration and high dynamic response in the stable operation of the motor are realized.

Description

Technical Field

[0001] This application relates to the field of compressor control, and in particular to a motor control method, controller, and electrical equipment based on single-resistor sampling. Background Technology

[0002] Balancing high performance and low cost, the industry widely adopts single-resistor sampling technology for bus current sampling. This solution requires only one sampling resistor to reconstruct the phase current, significantly reducing hardware costs. Therefore, it is widely used in cost-sensitive applications such as home appliances, fans, water pumps, and compressors. However, single-resistor sampling technology has inherent structural limitations: its effective sampling is highly dependent on the inverter being in a specific non-zero switching state, and a sufficient sampling time window is required to ensure sampling reliability.

[0003] In existing technologies, a fixed carrier frequency and symmetrical seven-segment SVPWM is commonly used throughout the entire motor operating range. This modulation method further divides the already short vector action time in half, resulting in a severely narrowed sampling time window, which can easily lead to sampling failure and thus cause risks such as startup instability, overcurrent, or even damage to power devices. Summary of the Invention

[0004] This application addresses at least one of the aforementioned technical problems to a certain extent. To this end, this application provides a motor control method, controller, and electrical equipment based on single-resistor sampling, which can ensure sampling reliability during the startup phase and achieve low-noise, high-performance motor control during the operation phase through coordinated switching of modulation strategies.

[0005] In a first aspect, embodiments of this application provide a motor control method based on single-resistor sampling, the method comprising: When the motor is in the startup phase, a five-segment space vector modulation strategy is used to generate a PWM signal to drive the motor; When the motor is in operation, a seven-segment space vector modulation strategy is used to generate a PWM signal to drive the motor.

[0006] In some embodiments, the method further includes: When the motor is in the startup phase, the PWM carrier frequency is set to a first carrier frequency, wherein the first carrier frequency is less than or equal to a first preset threshold.

[0007] In some embodiments, the method further includes: When the motor is in operation, the PWM carrier frequency is switched to a second carrier frequency, wherein the second carrier frequency is greater than or equal to a second preset threshold and the second carrier frequency is higher than the first carrier frequency.

[0008] In some embodiments, the method further includes: Obtain the DC bus voltage, target voltage vector, and current PWM carrier period; The duration of the basic voltage vector is calculated based on the DC bus voltage, the target voltage vector, and the current PWM carrier cycle. The sampling time window is determined based on the duration of action of the basic voltage vector.

[0009] In some embodiments, the basic voltage vector includes a first basic voltage vector and a second basic voltage vector, and the calculation of the duration of the basic voltage vector based on the DC bus voltage, the target voltage vector, and the current PWM carrier cycle includes: The duration of action of the fundamental voltage vector is calculated using the following formula: ; in, The duration of the first basic voltage vector is... The duration of action of the second fundamental voltage vector. The DC bus voltage is... = The PWM carrier period is... For PWM carrier frequency, The α-axis voltage vector of the target voltage vector. The β-axis voltage vector is the target voltage vector.

[0010] In some embodiments, the sampling time window includes a first sampling time window and a second sampling time window, and determining the sampling time window based on the duration of action of the basic voltage vector includes: The first sampling time window is determined based on the duration of action of the first basic voltage vector. The second sampling time window is determined based on the duration of action of the second basic voltage vector.

[0011] In some embodiments, the method further includes: Obtain the operating status parameters of the motor; Determine whether the operating status parameters meet the preset conditions; If so, then the motor is determined to be in operation. If not, then the motor is determined to be in the startup phase.

[0012] In some embodiments, the operating status parameter is the operating frequency, and the preset condition is that the operating frequency is greater than or equal to a preset frequency and the duration is greater than or equal to a preset duration; or, the operating status parameter is the modulation ratio, and the preset condition is that the modulation ratio is greater than or equal to a modulation ratio threshold.

[0013] Secondly, embodiments of this application provide a controller, the controller including at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores 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 motor control method based on single-resistance sampling as described above.

[0014] Thirdly, embodiments of this application provide an electrical device including a motor and a controller as described above, wherein the controller is connected to the motor.

[0015] Compared with existing technologies, this application has at least the following advantages: A five-segment space vector modulation strategy is used to generate PWM signals during the motor startup phase, and a seven-segment space vector modulation strategy is used during the motor operation phase. Therefore, the five-segment modulation strategy used in the startup phase focuses on concentrating zero vectors, ensuring the non-zero voltage vectors exist in a complete and continuous manner. This avoids the problem of halving the sampling time window due to symmetrical division of zero vectors in seven-segment modulation, making the sampling time window directly equal to the complete action time of the non-zero voltage vectors, doubling its width and providing sufficient setup time for the sampling circuit. This effectively resists switching noise interference and ensures the reliability of current sampling during heavy-load and low-speed startup. During the operation phase, the method switches to seven-segment modulation with symmetrical zero vector allocation, resulting in low current harmonics, low electromagnetic noise, and good high-frequency control performance, achieving quiet operation, low vibration, and high dynamic response during steady-state motor operation. Thus, this method achieves optimal comprehensive performance across the entire operating range by prioritizing sampling reliability during startup and pursuing high-quality performance during operation, under the constraint of single-resistor sampling hardware. Attached Figure Description

[0016] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0017] Figure 1 This is a schematic diagram of the structure of an electrical device provided in an embodiment of this application; Figure 2 This is a schematic diagram of a controller structure provided in an embodiment of this application; Figure 3 This is a schematic flowchart of one of the motor control methods based on single-resistor sampling provided in the embodiments of this application; Figure 4 This is a schematic diagram of one type of space voltage vector diagram provided in the embodiments of this application; Figure 5 This is a schematic diagram of a five-segment modulation pattern of sector 1 provided in one embodiment of this application; Figure 6 This is a schematic flowchart of one of the motor control methods based on single-resistor sampling provided in the embodiments of this application; Figure 7 This is a schematic diagram of a seven-segment modulation pattern of sector 1 provided in one embodiment of this application; Figure 8 This is a schematic diagram of a motor control device based on single-resistor sampling provided in an embodiment of this application. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application. All other embodiments obtained by those skilled in the art based on the embodiments in this application without inventive effort are within the scope of protection of this application.

[0019] It should be noted that, unless there is a conflict, the various features in the embodiments of this application can be combined with each other, all of which are within the protection scope of this application. Furthermore, although functional modules are divided in the device schematic diagram and a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in a different order than the module division in the device or the order in the flowchart. Moreover, the terms "first," "second," and "third" used in this application do not limit the data or execution order, but only distinguish identical or similar items with essentially the same function and effect.

[0020] Please see Figure 1 , Figure 1 This is a structural schematic diagram of an electrical device provided in an embodiment of this application. For example... Figure 1 As shown, the electrical device 100 includes a controller 10 and a motor 20, with the controller 10 electrically connected to the motor 20. The motor 20 is an AC motor, specifically a permanent magnet synchronous motor or an induction motor. The electrical device 100 can be a household appliance, fan, water pump, or compressor, or other equipment that requires motor drive.

[0021] The controller 10 is used to receive external commands (such as target speed, start / stop commands) and generate PWM signals based on the control method provided in this application to drive the motor 20 to run. The controller 10 integrates a processor, memory and power inverter circuit. In some embodiments, the power inverter circuit may also be a power inverter circuit independent of the controller 10.

[0022] To achieve more precise motor control, a single-resistor sampling method is typically used to sample the bus current. Specifically, single-resistor sampling involves connecting a sampling resistor in series on the DC bus side of the power inverter circuit. By detecting the voltage across this resistor and combining this with the current switching state of the power inverter circuit, the three-phase current of the motor can be reconstructed. Its working principle is based on the path characteristics of current: at any given time, the switching state of the three-phase bridge arms of the power inverter circuit determines the relationship between the DC bus current and the three-phase winding current. When the power inverter circuit is in a non-zero voltage vector action state, the bus current equals the current of a single phase winding; when it is in a zero-vector action state, the bus current is zero.

[0023] Therefore, by sampling the bus current at two different non-zero voltage vector action moments within a PWM cycle, the two-phase current values ​​can be obtained. Then, the third-phase current can be calculated according to Kirchhoff's current law Ia+Ib+Ic=0, thereby realizing the reconstruction of the three-phase current.

[0024] The core advantage of single-resistor sampling lies in its extremely low hardware cost. It only requires one sampling resistor and a corresponding signal conditioning circuit to achieve sampling. Compared with the solution using three current sensors or Hall elements, it can significantly reduce the cost and size of the controller, making it particularly suitable for cost-sensitive applications such as home appliances, fans, water pumps, and compressors.

[0025] However, single-resistor sampling has strict requirements on the sampling time window. Each valid sample must be completed within the duration of the non-zero voltage vector, and the sampling time must avoid voltage spikes caused by the switching transistor's on / off state. The width of the sampling time window is the duration of the non-zero voltage vector, and it must be greater than the minimum setup time of the sampling circuit (usually a few microseconds) to obtain a stable current value. If the sampling time window is too narrow, reliable sampling cannot be completed, leading to current reconstruction failure, which in turn affects the accuracy and stability of motor control.

[0026] In related technologies, a seven-segment space vector modulation strategy is commonly used to control motors throughout their entire operating range. This modulation strategy features low current harmonics, low electromagnetic noise, and good high-frequency control performance. However, during the motor startup phase, especially under heavy load and low speed conditions, the effective voltage vector's duration is extremely short. The seven-segment control vector modulation strategy further halves this duration, resulting in an extremely narrow available sampling time window for single-resistor sampling. This makes sampling failure highly likely, leading to startup instability, overcurrent, or even motor failure.

[0027] Based on the above reasons, this application provides a motor control method based on single-resistor sampling. This method uses a five-segment space vector modulation strategy to generate PWM signals when the motor is in the start-up phase, and uses a seven-segment space vector modulation strategy to generate PWM signals when the motor is in the running phase.

[0028] Therefore, this method employs a five-segment modulation strategy during the startup phase. Its core lies in concentrating the zero vectors, ensuring the non-zero voltage vectors exist in a complete and continuous manner. This avoids the problem of halving the sampling time window caused by symmetrical division of the zero vectors in seven-segment modulation, making the sampling time window directly equal to the complete duration of the non-zero voltage vectors, effectively doubling its width. This provides sufficient setup time for the sampling circuit, effectively resisting switching noise interference and ensuring the reliability of current sampling during heavy-load and low-speed startup. During the operation phase, it switches to seven-segment modulation with symmetrical zero vector allocation, resulting in low current harmonics, low electromagnetic noise, and good high-frequency control performance, achieving quiet operation, low vibration, and high dynamic response during steady-state motor operation. Thus, this method, through differentiated configuration that prioritizes sampling reliability during startup and high-quality performance during operation, achieves optimal comprehensive performance across the entire operating range under the constraint of single-resistor sampling hardware.

[0029] Please refer to the following: Figure 2 , Figure 2 This is a schematic diagram of the hardware structure of a controller provided in an embodiment of this application. The controller 20 includes at least one processor 201 that is communicatively connected via a system bus or other means. Figure 2 (Taking a processor as an example) and memory 202. The controller 20 can exist in the form of a chip.

[0030] The memory 202 stores instructions that can be executed by the at least one processor 201. The instructions are executed by the at least one processor 201, which provides computing and control capabilities to execute relevant commands, such as controlling the controller 20 to execute any of the single-resistance sampling-based motor control methods provided in the following embodiments of this application.

[0031] The memory 202, as a non-transitory computer-readable storage medium, can be used to store non-transitory software programs, non-transitory computer-executable programs, and modules, such as the program instructions / modules corresponding to the motor control method based on single-resistance sampling provided in the following embodiments of this application. The processor 201, by running the non-transitory software programs, instructions, and modules stored in the memory 202, can implement the motor control method based on single-resistance sampling in any of the following method embodiments. Specifically, the memory 202 may include high-speed random access memory and may also include non-transitory memory, such as at least one disk storage device, flash memory device, or other non-transitory solid-state storage device. In some embodiments, the memory 202 may also include memories remotely located relative to the processor 201, and these remote memories can be connected to the processor 201 via a network. Examples of such networks include, but are not limited to, the Internet, enterprise intranets, local area networks, mobile communication networks, and combinations thereof.

[0032] In some embodiments, controller 20 may be a general-purpose processor, digital signal processor (DSP), application-specific integrated circuit (ASIC), field-programmable gate array (FPGA), microcontroller, ARM (Acorn RISC Machine) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination of these components. Additionally, controller 20 may also be any conventional processor, controller, microcontroller, or state machine. Controller 20 may also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors combined with a DSP, and / or any other such configuration.

[0033] This application provides a motor control method based on single-resistor sampling. Please refer to [link to relevant documentation]. Figure 3 , Figure 3 This is a flowchart illustrating a motor control method based on single-resistor sampling provided in an embodiment of this application. Method S100 includes, but is not limited to, the following steps: S101: When the motor is in the starting stage, a five-segment space vector modulation strategy is used to generate a PWM signal to drive the motor; When the motor starts working, the controller monitors the motor's operating status parameters in real time. These parameters include, but are not limited to, the motor's operating frequency, modulation ratio, and speed. Based on these parameters, the controller determines whether the motor is currently in the startup or running phase.

[0034] If the operating status parameters meet the preset conditions, the motor is determined to be in the running stage; if the operating status parameters do not meet the preset conditions, the motor is determined to be in the starting stage. The preset conditions can be determined based on the specific form of the operating status parameters.

[0035] For example, if the operating status parameter is the operating frequency, then the preset condition is that the operating frequency is greater than or equal to the preset frequency and the duration is greater than or equal to the preset duration. That is, if the operating frequency of the motor is greater than or equal to the preset frequency and the duration is greater than or equal to the preset duration, then the motor is determined to be in the operating stage; otherwise, the motor is determined to be in the starting stage.

[0036] For example, if the operating status parameter is the modulation ratio, the preset condition is that the modulation ratio is greater than or equal to the modulation ratio threshold. That is, if the modulation ratio of the motor is greater than or equal to the modulation ratio threshold, the motor is determined to be in the running stage; otherwise, the motor is determined to be in the starting stage.

[0037] The preset frequency, preset duration, and modulation ratio threshold can all be set as needed. In this embodiment, the preset frequency is 5 Hz, the preset duration is 5 s, and the modulation ratio threshold is 0.25.

[0038] After determining the current operating state of the motor, different modulation strategies are used to control the motor. When the motor is in the starting phase, a five-segment space vector modulation strategy is used to generate a PWM signal to drive the motor.

[0039] Please see Figure 4 , Figure 4 A spatial voltage vector diagram is provided as an embodiment of this application. For example... Figure 4 As shown, the three arms of the power inverter circuit have eight switching states, corresponding to eight voltage vectors, six of which are non-zero vectors (V1 to V6) and two are zero vectors (V0 and V7). The six non-zero vectors are spatially separated by 60°, dividing the plane into six sectors. The amplitude of each non-zero vector is 2 / 3Udc (Udc is the DC bus voltage), and its direction remains fixed. The amplitude of the zero vector is zero.

[0040] The basic voltage vector is the fundamental unit for synthesizing any target voltage vector. The controller synthesizes the desired target voltage vector within one PWM cycle by adjusting the action time ratio of two adjacent basic voltage vectors. Taking sector 1 as an example, the two basic voltage vectors of this sector are V4 and V6. V4 corresponds to the switching states of the upper U-phase bridge arm, lower V-phase bridge arm, and lower W-phase bridge arm (i.e., (1,0,0)), with its direction coinciding with the α-axis. V6 corresponds to the switching states of the upper U-phase bridge arm, upper V-phase bridge arm, and lower W-phase bridge arm (i.e., (1,1,0)), with its direction making a 60° angle with the α-axis. Therefore, according to the voltage vector synthesis theorem, we can obtain: (1) Where V4 is one of the fundamental voltage vectors of sector 1, and V6 is another fundamental voltage vector of sector 1. Let T1 be the duration of V4 and T2 be the duration of V6. This represents the current PWM carrier cycle.

[0041] In a single-resistor sampling system, the duration of the fundamental voltage vector determines the width of the sampling time window, which in turn directly determines the reliability of single-resistor sampling. During motor startup, especially under heavy load and low speed (low modulation ratio) conditions, the target voltage vector amplitude is very small, resulting in an extremely short duration of the fundamental voltage vector and an extremely narrow sampling time window, which easily leads to sampling failure.

[0042] Therefore, in this embodiment, a five-segment space vector modulation strategy is adopted during the motor start-up phase. Please refer to [link to relevant documentation]. Figure 5 , Figure 5 This application provides a five-segment modulation pattern for sector 1. For example... Figure 5 As shown, five-segment space vector modulation (also known as discontinuous pulse width modulation, or DPWM for short) concentrates the zero vectors within one PWM cycle, ensuring that one phase bridge arm switch remains stationary. Taking sector 1 as an example, its voltage vector sequence is V4→V6→V7→V6→V4.

[0043] from Figure 5 As can be seen, the action times T1 and T2 of non-zero vectors V4 and V6 exist in a complete and continuous form, without being divided by the zero vector. Therefore, the sampling time window is directly equal to the complete action time of the basic vectors, i.e., the first sampling time window Tsamp1 = T1, and the second sampling time window Tsamp2 = T2. Since the non-zero vectors are not divided, the sampling time window is relatively wide, which can meet the minimum settling time requirement of the sampling circuit, ensuring reliable acquisition of phase current during heavy load and low-speed start-up phases, and providing an accurate data basis for subsequent three-phase current reconstruction and rotor position estimation.

[0044] In related technologies, a seven-segment modulation control of the motor is used. This seven-segment modulation symmetrically distributes the zero vector and divides the non-zero vector into two segments, halving the sampling time window. This makes sampling prone to failure during the startup phase due to the excessively narrow sampling time window. However, in this embodiment, the controller uses a five-segment modulation control of the motor, avoiding the segmentation of the sampling time window from the modulation strategy level, thus fundamentally ensuring the reliability of single-resistor sampling during the startup phase.

[0045] In some embodiments, the duration of action of the basic voltage vector is first calculated based on the volt-second balance principle, and then the sampling time window is determined based on the duration of action of the basic voltage vector.

[0046] Specifically, such as Figure 6 As shown, the method S100 further includes: S103: Obtain the DC bus voltage, target voltage vector, and current PWM carrier period; During motor operation, the controller first needs to acquire key parameters for calculating the duration of the basic voltage vector. The DC bus voltage Udc is acquired in real-time by a voltage sampling circuit, and its value reflects the energy supply status of the power inverter circuit. The target voltage vector is output by the current loop controller after proportional-integral adjustment based on the current error. Then, its components Vα and Vβ in the stationary α-β coordinate system are obtained through Park inverse transform. These two components characterize the magnitude and direction of the composite voltage vector that the controller expects to apply to the motor windings at the current moment. The PWM carrier period T... PWM The carrier frequency F set in the controller PWM Decision, satisfying T PWM =1 / F PWM This cycle determines the switching frequency of the switching transistor and the total duration of each PWM cycle.

[0047] S104: Calculate the duration of the basic voltage vector based on the DC bus voltage, the target voltage vector, and the current PWM carrier cycle; After obtaining the above parameters, the controller calculates the duration of the basic voltage vector based on the principle of space vector modulation. According to the voltage vector synthesis theorem, within one PWM cycle, the effect of synthesizing the target voltage vector from the basic voltage vector is equivalent to the weighted sum of the duration and amplitude of each vector.

[0048] The fundamental voltage vectors include the first fundamental voltage vector and the second fundamental voltage vector, whose durations are denoted as T1 and T2, respectively. Taking sector 1 as an example, the first fundamental voltage vector is V4, the second fundamental voltage vector is V6, and their durations are denoted as T1 and T2, respectively. The duration of the zero vector is denoted as T7. According to the voltage vector composition theorem, the above formula (1) can be obtained.

[0049] To solve for T1 and T2, the above vector relationships need to be projected onto the α-β coordinate system. Based on the geometric relationships, by simultaneously solving the voltage decomposition formulas along the α and β axes, the following system of equations is obtained: (2) in, The duration of the first fundamental voltage vector. The duration of action of the second fundamental voltage vector. The DC bus voltage is... The α-axis voltage vector of the target voltage vector. The β-axis voltage vector of the target voltage vector. = For PWM carrier period, This is the PWM carrier frequency.

[0050] Solving the above system of equations yields the duration of action of the fundamental voltage vector: (3) in, The duration of the first fundamental voltage vector. The duration of action of the second fundamental voltage vector. This is the DC bus voltage. = For PWM carrier period, For PWM carrier frequency, The α-axis voltage vector of the target voltage vector. The β-axis voltage vector is the target voltage vector.

[0051] S105: Determine the sampling time window based on the duration of action of the basic voltage vector.

[0052] The duration of the first basic voltage vector, T1, and the duration of the second basic voltage vector, are calculated using formula (3). Then, the first sampling time window, Tsamp1, is determined based on the duration of the first basic voltage vector, and the second sampling time window is determined based on the duration of the second basic voltage vector, Tsamp2.

[0053] Taking sector 1 as an example, the voltage vector sequence is V4→V6→V7→V6→V4, where the non-zero vectors V4 and V6 appear in a complete and continuous form. At this time, the first sampling time window Tsamp1 corresponds to the duration of V4, i.e., Tsamp1=T1, and this window is used to collect the current of the corresponding phase. The second sampling time window Tsamp2 corresponds to the duration of V6, i.e., Tsamp2=T2.

[0054] The duration T7 of the zero vector V7 is calculated by the following formula: T7=T PWM T1 T2(4) The period during which the zero vector acts can also serve as an auxiliary sampling time window.

[0055] In some embodiments, it can be seen from formula (3) that the duration of the first basic voltage vector T1 and the duration of the second basic voltage vector T2 are both inversely proportional to the DC bus voltage Udc and to the PWM carrier period T. PWM It is proportional to the α-β axis components of the target voltage vector and varies linearly with them.

[0056] Therefore, in order to create a wider sampling time window, when the motor is in the startup phase, the PWM carrier frequency is set to a first carrier frequency, wherein the first carrier frequency is less than or equal to a first preset threshold.

[0057] During the motor startup phase, the PWM carrier frequency is set to the first carrier frequency T. PWM_low Lowering the PWM carrier frequency to a lower level effectively extends the PWM carrier period, thus amplifying the durations T1 and T2 of the basic voltage vector. Combined with the characteristic of maintaining a complete sampling time window under five-segment modulation, the sampling time window width can be increased several times, fully meeting the minimum settling time requirements of the sampling circuit and fundamentally ensuring the reliability of single-resistor sampling under heavy load and low-speed conditions. Simultaneously, the lower PWM carrier frequency reduces the number of switching transistor operations, significantly reducing switching losses and peak junction temperatures during startup, alleviating thermal stress concentration in the power inverter circuit, and improving system durability and power density.

[0058] S102: When the motor is in operation, a seven-segment space vector modulation strategy is used to generate a PWM signal to drive the motor.

[0059] Please see Figure 7 , Figure 7 A seven-segment modulation pattern for sector 1 provided in this application embodiment, such as Figure 7 As shown, seven-segment space vector modulation (also known as continuous space vector pulsation, CSVPWM or SVPWM) symmetrically distributes the zero vector within one PWM cycle, with all bridge arms operating twice. Taking sector 1 as an example, its voltage vector sequence is V0→V4→V6→V7→V6→V4→V0. From Figure 7 As can be seen, the action times T1 and T2 of the non-zero vectors V4 and V6 are symmetrically divided into two segments by the zero vector, with each segment having an action time of only T1 / 2 and T2 / 2. Therefore, the first sampling time window Tsamp1 = T1 / 2 and the second sampling time window Tsamp2 = T2 / 2, with the window width halved compared to the five-segment method. The calculation of T1 and T2 can be performed using formula (3), which will not be elaborated here.

[0060] The duration of action of zero vectors V0(000) and V7(111) is (5) The period during which the zero vector acts can also serve as an auxiliary sampling time window.

[0061] When the motor is running, the controller uses a seven-segment space vector modulation strategy to generate a PWM signal to drive the motor. Although the sampling time window is narrow, the current waveform is closer to a sine wave, with low harmonic content, low electromagnetic noise, and fast dynamic response, which can better meet the requirements of high performance and low noise for steady-state operation of the motor.

[0062] In some embodiments, when the motor is in operation, the PWM carrier frequency is switched to a second carrier frequency, wherein the second carrier frequency is greater than or equal to a second preset threshold and is higher than the first carrier frequency.

[0063] Specifically, after the motor completes the startup phase and enters steady-state operation, the controller changes the PWM carrier frequency from the first carrier frequency T used during the startup phase. PWM_low (e.g., 3kHz to 5kHz) Switch to a higher second carrier frequency T PWM_high (For example, 8kHz to 16kHz or higher). The second carrier frequency T PWM_high The setting can be optimized based on the motor's rated parameters, switching device characteristics, and system efficiency requirements, and is typically set to be higher than the first carrier frequency T. PWM_low Several times that of the motor. During the switching process, the controller synchronously adjusts the PWM cycle count and timer configuration to ensure a smooth and uninterrupted frequency switching process, avoiding any impact on motor operation.

[0064] By increasing the PWM carrier frequency to a higher level, switching noise can be shifted out of the frequency range sensitive to the human ear, significantly reducing electromagnetic noise and achieving quiet motor operation. Simultaneously, a higher PWM carrier frequency reduces current ripple and lowers the total harmonic distortion (THD), making the current waveform closer to a sine wave, thereby reducing torque pulsation and motor vibration. Furthermore, increasing the PWM carrier frequency also means a shorter current loop control cycle and increased control bandwidth, enabling the motor to have faster dynamic response and stronger disturbance rejection performance during sudden load changes or speed adjustments, thus meeting the high performance and low noise requirements for steady-state motor operation.

[0065] In summary, this motor control method based on single-resistor sampling employs a five-segment modulation strategy during the startup phase. Its core lies in concentrating the zero vectors, ensuring the non-zero voltage vectors exist in a complete and continuous manner. This avoids the problem of halving the sampling time window caused by symmetrical division of the zero vectors in seven-segment modulation, making the sampling time window directly equal to the complete duration of the non-zero voltage vectors, effectively doubling its width. This provides ample settling time for the sampling circuit, effectively resisting switching noise interference and ensuring the reliability of current sampling during heavy-load and low-speed startup. During the operation phase, it switches to seven-segment modulation with symmetrical zero vector distribution, resulting in low current harmonics, low electromagnetic noise, and good high-frequency control performance, achieving quiet operation, low vibration, and high dynamic response during steady-state motor operation.

[0066] It should be noted that in the above embodiments, there is no necessarily a certain order between the above steps. Those skilled in the art can understand from the description of the embodiments of this application that the above steps may have different execution orders in different embodiments, that is, they may be executed in parallel or in interchange, etc.

[0067] As another aspect of the embodiments of this application, this application provides a motor control device based on single-resistor sampling. The motor control device based on single-resistor sampling can be a software module, which includes several instructions stored in the memory of a controller. The processor can access the memory, call the instructions, and execute them to complete the motor control method based on single-resistor sampling described in the above embodiments.

[0068] In some embodiments, the motor control device based on single-resistance sampling can also be constructed from hardware devices. For example, the motor control device based on single-resistance sampling can be constructed from one or more chips, which can work together to complete the motor control method based on single-resistance sampling described in the above embodiments. As another example, the motor control device based on single-resistance sampling can also be constructed from various logic devices, such as general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), microcontrollers, ARM (Acorn RISC Machine) or other programmable logic devices, discrete gate or transistor logic, discrete hardware components, or any combination of these components.

[0069] Please see Figure 8 , Figure 8 This application provides a motor control device based on single-resistor sampling. The motor control device 200 based on single-resistor sampling includes a first modulation module 201 and a second modulation module 202.

[0070] The first modulation module 201 is used to generate a PWM signal to drive the motor using a five-segment space vector modulation strategy when the motor is in the start-up phase, and the second modulation module 202 is used to generate a PWM signal to drive the motor using a seven-segment space vector modulation strategy when the motor is in the running phase.

[0071] Therefore, the motor control device based on single-resistor sampling adopts a five-segment modulation strategy during the startup phase. Its core lies in concentrating the zero vectors, ensuring the non-zero voltage vectors exist in a complete and continuous manner. This avoids the problem of halving the sampling time window caused by symmetrical division of the zero vectors in seven-segment modulation, making the sampling time window directly equal to the complete duration of the non-zero voltage vectors, doubling its width. This provides sufficient settling time for the sampling circuit, effectively resisting switching noise interference and ensuring the reliability of current sampling during heavy-load and low-speed startup. During the operation phase, it switches to seven-segment modulation with symmetrical zero vector distribution, resulting in low current harmonics, low electromagnetic noise, and good high-frequency control performance, achieving quiet operation, low vibration, and high dynamic response during steady-state motor operation.

[0072] It should be noted that since the motor control device 200 based on single-resistance sampling and the motor control method based on single-resistance sampling in the above embodiments are based on the same application concept, the corresponding contents in the above method embodiments are also applicable to the device embodiments, and will not be described in detail here.

[0073] This application also provides a non-transitory computer-readable storage medium storing computer-executable instructions that are executed by one or more processors, for example... Figure 2 One of the processors 201 enables the one or more processors to execute the motor control method based on single-resistor sampling in any of the above method embodiments.

[0074] This application also provides a computer program product, which includes a computer program stored on a non-transitory computer-readable storage medium. The computer program includes program instructions, which, when executed by a controller 20, cause the controller 20 to execute any of the motor control methods based on single-resistance sampling described in the present invention.

[0075] In summary, this motor control method based on single-resistor sampling employs a five-segment modulation strategy during the startup phase. Its core lies in concentrating the zero vectors, ensuring the non-zero voltage vectors exist in a complete and continuous manner. This avoids the problem of halving the sampling time window caused by symmetrical division of the zero vectors in seven-segment modulation, making the sampling time window directly equal to the complete duration of the non-zero voltage vectors, effectively doubling its width. This provides ample settling time for the sampling circuit, effectively resisting switching noise interference and ensuring the reliability of current sampling during heavy-load and low-speed startup. During the operation phase, it switches to seven-segment modulation with symmetrical zero vector distribution, resulting in low current harmonics, low electromagnetic noise, and good high-frequency control performance, achieving quiet operation, low vibration, and high dynamic response during steady-state motor operation.

[0076] The device or equipment embodiments described above are merely illustrative. The unit modules described as separate components may or may not be physically separate. The components shown as module units may or may not be physical units; that is, they may be located in one place or distributed across multiple network module units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs.

[0077] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented using software plus a general-purpose hardware platform, or of course, using hardware. Based on this understanding, the above technical solutions, in essence or the parts that contribute to the related technology, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the motor control method based on single-resistance sampling described in various embodiments or some parts of embodiments.

[0078] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them; under the concept of this application, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of this application as described above, which are not provided in detail for the sake of brevity; although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A motor control method based on single-resistor sampling, characterized in that, The method includes: When the motor is in the startup phase, a five-segment space vector modulation strategy is used to generate a PWM signal to drive the motor; When the motor is in operation, a seven-segment space vector modulation strategy is used to generate a PWM signal to drive the motor.

2. The method according to claim 1, characterized in that, The method further includes: When the motor is in the startup phase, the PWM carrier frequency is set to a first carrier frequency, wherein the first carrier frequency is less than or equal to a first preset threshold.

3. The method according to claim 2, characterized in that, The method further includes: When the motor is in operation, the PWM carrier frequency is switched to a second carrier frequency, wherein the second carrier frequency is greater than or equal to a second preset threshold and the second carrier frequency is higher than the first carrier frequency.

4. The method according to claim 1, characterized in that, The method further includes: Obtain the DC bus voltage, target voltage vector, and current PWM carrier period; The duration of the basic voltage vector is calculated based on the DC bus voltage, the target voltage vector, and the current PWM carrier cycle. The sampling time window is determined based on the duration of action of the basic voltage vector.

5. The method according to claim 4, characterized in that, The basic voltage vector includes a first basic voltage vector and a second basic voltage vector. The calculation of the duration of the basic voltage vector based on the DC bus voltage, the target voltage vector, and the current PWM carrier cycle includes: The duration of action of the fundamental voltage vector is calculated using the following formula: ； in, The duration of the first basic voltage vector is... The duration of action of the second fundamental voltage vector. The DC bus voltage is... = The PWM carrier period is... For PWM carrier frequency, The α-axis voltage vector of the target voltage vector. The β-axis voltage vector is the target voltage vector.

6. The method according to claim 5, characterized in that, The sampling time window includes a first sampling time window and a second sampling time window. Determining the sampling time window based on the duration of action of the basic voltage vector includes: The first sampling time window is determined based on the duration of action of the first basic voltage vector. The second sampling time window is determined based on the duration of action of the second basic voltage vector.

7. The method according to claim 1, characterized in that, The method further includes: Obtain the operating status parameters of the motor; Determine whether the operating status parameters meet the preset conditions; If so, then the motor is determined to be in operation. If not, then the motor is determined to be in the startup phase.

8. The method according to claim 7, characterized in that, The operating status parameter is the operating frequency, and the preset condition is that the operating frequency is greater than or equal to the preset frequency and the duration is greater than or equal to the preset duration. Alternatively, the operating status parameter is the modulation ratio, and the preset condition is that the modulation ratio is greater than or equal to the modulation ratio threshold.

9. A controller, characterized in that, The controller includes: At least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor to enable the at least one processor to perform the motor control method based on single-resistance sampling as described in any one of claims 1-8.

10. An electrical device, characterized in that, It includes a motor and a controller as described in claim 9, wherein the controller is connected to the motor.

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