Secondary frequency modulation control method and device based on single-resistor sampling phase current reconstruction

Abstract

The application discloses a secondary frequency modulation control method based on single-resistance sampling phase current reconstruction, which comprises the following steps: obtaining a to-be-sampled period PWM signal; calculating a voltage vector and judging a region where the voltage vector is located; when the voltage vector is located at a sector edge, performing secondary modulation on a single-phase PWM signal, and respectively inserting one-half of an ADC current sampling window width into rising edges and falling edges of the PWM signal which needs secondary frequency modulation; when the voltage vector is located at a low-voltage modulation region, performing secondary modulation on one-phase PWM signal in a previous period, respectively inserting one-half of an ADC current sampling window width into rising edges and falling edges of the PWM signal which needs secondary frequency modulation, performing secondary modulation on another-phase PWM signal in an adjacent next period, and respectively inserting one-half of an ADC current sampling window width into rising edges and falling edges of the PWM signal which needs secondary frequency modulation. The application solves the single-resistance sampling phase current reconstruction problem by using the method of performing secondary frequency modulation on the SPWM control signal by the IPWM signal.

Description

TECHNICAL FIELD

[0001] The application relates to a secondary frequency modulation control method and device based on single-resistor sampling phase current reconstruction. BACKGROUND

[0002] In field-oriented control (FOC) of brushless direct current motor (BLDC) or permanent magnet synchronous motor (PMSM), current sampling is a key step, which directly affects the accuracy and efficiency of motor control. Current sampling is usually achieved through Hall sensors or shunt resistors. Shunt resistors mainly include single-resistor, double-resistor and triple-resistor.

[0003] The advantages of Hall sensor current sampling include non-contact measurement, ability to withstand high voltage, easy installation, low maintenance cost, fast response speed, etc. However, Hall sensors also have their limitations, such as the Hall voltage signal is usually small and needs to be processed through an amplification circuit; in addition, the accuracy of Hall sensors may be affected by factors such as temperature and magnetic core saturation. When designing a Hall sensor current sampling system, these factors need to be considered to ensure the accuracy and reliability of the measurement.

[0004] Double-resistor sampling detects current by connecting resistors in series in two phases. It can sample when all the lower bridge arms are conducting, which can reduce sampling error. However, this method still has a window time limit, i.e. the bridge low end cannot be closed before the ADC conversion is completed, which may affect the accuracy of the sampling. Triple-resistor sampling detects current by connecting resistors in series in all three phases of the three-phase inverter, and the sampling accuracy is higher, but the cost is correspondingly higher.

[0005] Single-resistor sampling is a low-cost method that detects current by connecting a resistor in series in any phase of the motor's three-phase inverter. Since two samplings are needed in a PWM cycle to reconstruct the three-phase current, the implementation of this method is more complex. The phase-shifted and simple deformation methods are commonly used to meet the sampling window width requirements, which can solve the sampling problem, but they are prone to harmonics, affecting the accuracy of current measurement. SUMMARY

[0006] To solve the problem of single-resistor sampling phase current reconstruction difficulty in the unobservable area, the application provides a secondary frequency modulation control method and device based on single-resistor sampling phase current reconstruction, which solves the problem of single-resistor sampling phase current reconstruction by using the method of secondary frequency modulation of SPWM control signal by IPWM signal.

[0007] According to an aspect of the application, a secondary frequency modulation control method based on single-resistor sampling phase current reconstruction is provided, comprising:

[0008] acquiring a PWM signal to be sampled;

[0009] The voltage vector is calculated and its region is determined;

[0010] When the voltage vector is located at the edge of the sector, the single-phase PWM signal is twice modulated, and one-half of the ADC current sampling window width is inserted into the rising edge and the falling edge of the PWM signal which needs twice frequency modulation;

[0011] When the voltage vector is located at the low voltage modulation region, one of the phase PWM signals is twice modulated in the previous period, and one-half of the ADC current sampling window width is inserted into the rising edge and the falling edge of the PWM signal which needs twice frequency modulation, and the other phase PWM signal is twice modulated in the adjacent next period, and one-half of the ADC current sampling window width is inserted into the rising edge and the falling edge of the PWM signal which needs twice frequency modulation.

[0012] As a further technical solution, when the voltage vector is located inside the sector, the phase current sampling is directly performed.

[0013] As a further technical solution, according to the obtained phase current sampling data inside the sector, at the edge of the sector and in the low voltage modulation region, the phase current reconstruction is performed.

[0014] As a further technical solution, the PWM signal to be sampled in the period is obtained, including: obtaining three-phase SPWM control signals in the period to be sampled, and the SPWM control signals are output in a center alignment mode.

[0015] As a further technical solution, the method further includes:

[0016] According to the ADC minimum sampling time and the dead time, the ADC current sampling window width is calculated;

[0017] The IPWM channel output is configured as a twice frequency modulation signal, the IPWM matching value is determined according to the sampling window width, so that the IPWM output pulse width length is the same as the sampling window width, and the period is the same as the SPWM control signal period;

[0018] The SPWM channel and the IPWM channel modulation enable are configured, which are used to control whether the SPWM arbitrary channel is operated with the IPWM signal to realize the twice frequency modulation of the SPWM control signal.

[0019] As a further technical solution, the method further includes:

[0020] When the SPWM modulation enable is opened, and the IPWM output is high, the SPWM outputs according to the original signal, and when the IPWM output is low, the SPWM output is low;

[0021] When the SPWM modulation is enabled to be turned off, the SPWM outputs according to the original signal.

[0022] According to an aspect of the present application, a kind of secondary frequency modulation control device based on single resistance sampling phase current reconstruction, comprising:

[0023] The acquisition module is configured to acquire a PWM signal to be sampled in a period.

[0024] The region determining module is configured to calculate a voltage vector and determine a region in which the voltage vector is located.

[0025] The sector edge processing module is configured to, when the voltage vector is located at a sector edge, perform secondary modulation on the single-phase PWM signal, and insert one-half of the ADC current sampling window width into a rising edge and a falling edge of the PWM signal that needs secondary frequency modulation.

[0026] The low-voltage modulation region processing module is configured to, when the voltage vector is located in a low-voltage modulation region, perform secondary modulation on one of the PWM signals in a previous period, and insert one-half of the ADC current sampling window width into a rising edge and a falling edge of the PWM signal that needs secondary frequency modulation, and perform secondary modulation on the other of the PWM signals in an adjacent next period, and insert one-half of the ADC current sampling window width into a rising edge and a falling edge of the PWM signal that needs secondary frequency modulation.

[0027] As a further technical solution, the application further comprises a configuration module configured to calculate the ADC current sampling window width according to the minimum ADC sampling time and the dead time, configure the IPWM channel output as a secondary frequency modulation signal, determine the IPWM matching value according to the sampling window width, so that the IPWM output pulse width length is the same as the sampling window width, and the period is the same as the SPWM control signal period, and configure the SPWM channel and the IPWM channel modulation enable, to control whether the SPWM arbitrary channel performs a phase operation with the IPWM signal, so as to realize secondary frequency modulation on the SPWM control signal.

[0028] According to an aspect of the present application, a kind of secondary frequency modulation control device based on single resistance sampling phase current reconstruction, comprising:

[0029] According to an aspect of the present application, a kind of computer program product, comprising computer program, the computer program is executed by processor to realize the step of the secondary frequency modulation control method based on single resistance sampling phase current reconstruction.

[0030] Compared with the prior art, the application has the following beneficial effects:

[0031] 1.The application adopts IPWM signals to modulate the sampled SPWM signals twice, and adjusts the SPWM waveforms at the sector edges and low-voltage modulation area to complete three-phase current reconstruction, which can solve the problem that the single-resistor sampling phase current reconstruction cannot be sampled in the non-observation area.

[0032] 2.The application can realize the phase and operation of the arbitrary phase control signal in the three-phase SPWM and the IPWM signal by controlling the SPWM modulation enable switch, and can realize the periodic adjustment of the three-phase SPWM signal.

[0033] 3.The application mainly realizes control through the hardware of the chip, has small system software overhead, and does not introduce additional hardware to increase the cost. DETAILED DESCRIPTION

[0034] Figure 1 The single-resistor sampling current reconstruction non-observation area provided for the embodiment of the application is shown in the figure.

[0035] Figure 2 The phase current reconstruction flowchart provided for the embodiment of the application is shown in the figure.

[0036] Figure 3 The sector edge SPWM output and the output waveform of the secondary modulation and change provided for the embodiment of the application are shown in the figure.

[0037] Figure 4 The low-voltage modulation area SPWM output and the output waveform of the secondary modulation and change provided for the embodiment of the application are shown in the figure.

[0038] Figure 5 The structure diagram of the secondary frequency modulation control device based on the single-resistor sampling phase current reconstruction provided for the embodiment of the application is shown in the figure. DETAILED DESCRIPTION

[0039] In the prior art, the Hall sensor current sampling, double-resistor and three-resistor current sampling have high cost, and the double-resistor and three-resistor sampling also have the limitation of the sampling window. In the single-resistor sampling application, at the sector edge of the vector voltage and in the low-voltage modulation area, enough sampling time cannot be reserved, and we call these areas current reconstruction non-observation areas. In view of the problem that the single-resistor sampling has difficulty in sampling the phase current in the current reconstruction non-observation area, most applications adopt the method of phase shifting or simply deforming the PWM control signal to generate an ADC sampling window that meets the requirements, both of which can solve the non-observation area sampling problem to a certain extent, but the phase shift will produce harmonics, and the reconstructed current waveform has high distortion rate, and the simple waveform transformation of the PWM will cause output voltage error, which also causes current distortion.

[0040] To this end, the application proposes a method of secondary frequency modulation of SPWM control signals by IPWM signals to solve the problem of single-resistor sampling phase current reconstruction in the non-observation area.

[0041] It should be noted that:

[0042] The SPWM (Shared Plused Width Modulation) mentioned in the specification of the application is 8-channel output, which is controlled by one counter, and the multi-channel output has the same period, but the duty cycle can be independently adjusted. IPWM (Independent Plused Width Modulation) is 4-channel output, each channel is controlled by a single counter, and the period and duty cycle of each channel can be independently controlled.

[0043] The technical solutions of the application will be described clearly and completely in combination with the drawings in the application. Obviously, the described embodiments are only a part of the embodiments of the application, not all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor belong to the protection scope of the application.

[0044] The embodiment of the application provides a secondary frequency modulation control method based on single-resistor sampling phase current reconstruction. The method is applied to single-resistor sampling current reconstruction, and solves the problem that it is difficult to sample bus current in the sector transition area and low voltage modulation area by the way of secondary modulation of SPWM control signals by IPWM signals.

[0045] The method for secondary frequency modulation control based on single-resistance sampling phase current reconstruction provided by the embodiment of the application first sets different phase current sampling modes for voltage vectors falling into different regions. Then, three-phase SPWM control signals of a sampling period are acquired, and it is judged to which region the voltage vector belongs. If the voltage vector is inside a sector, phase current sampling is directly performed. If the voltage vector is not inside the sector, it is further judged whether the voltage vector is located at a sector edge or a low-voltage modulation region. Then, if the voltage vector is located at the sector edge, single-phase PWM signals are subjected to secondary modulation, and one-half of the ADC current sampling window width is respectively inserted into rising edges and falling edges of the PWM signals requiring secondary frequency modulation. If the voltage vector is located at the low-voltage modulation region, one of the single-phase PWM signals is subjected to secondary modulation in a previous period, one-half of the ADC current sampling window width is respectively inserted into rising edges and falling edges of the PWM signals requiring secondary frequency modulation, then the other one of the single-phase PWM signals is subjected to secondary modulation in an adjacent next period, and one-half of the ADC current sampling window width is respectively inserted into rising edges and falling edges of the PWM signals requiring secondary frequency modulation. Finally, phase current reconstruction is performed according to phase current sampling data.

[0046] According to the minimum sampling time and dead time of the ADC, the ADC current sampling window width Tmin is calculated in the embodiment of the application. The IPWM channel output is configured as a secondary frequency modulation signal, the IPWM matching value is determined according to the sampling window length, the IPWM output pulse width length is ensured to be the same as Tmin, and the IPWM output period is ensured to be the same as the SPWM control signal period. The SPWM channel and the IPWM channel modulation enable are set, and it is controlled whether the SPWM arbitrary channel is subjected to AND operation with the IPWM signal, so as to achieve the purpose of secondary frequency modulation of the SPWM control signal.

[0047] Further, when the SPWM modulation enable is turned on and the IPWM output is high, the SPWM outputs according to the original signal; when the IPWM output is low, the SPWM output is low; and when the SPWM modulation enable is turned off, the SPWM outputs according to the original signal. Based on this secondary frequency modulation mode, any one of the three-phase SPWM control signals can be flexibly controlled.

[0048] According to the output voltage, the reference voltage is calculated in the embodiment of the application, and the output voltage sector is determined according to the reference voltage calculation. When the vector voltage is located inside the sector, the difference between two-phase SPWM edges is greater than the ADC current sampling window width Tmin, the phase current is sampled at the trigger point, and the phase current is calculated according to the sampling current and the output voltage sector.

[0049] When the vector voltage is located at the sector edge, the two-phase SPWM edge difference is less than the ADC current sampling window width Tmin, and in this case, the A-phase current can only be sampled at the trigger point. To meet the requirement of the ADC current sampling window width, a low level with a width greater than or equal to Tmin needs to be output at the center of one of the two-phase SPWM signals with close edges, and the specific operation is to enable the corresponding SPWM signal modulation function, so that the SPWM signal can be obtained by the AND operation with the IPWM signal. After the secondary frequency modulation, the sampling SPWM waveform center point can generate a low pulse width of the sampling window width, and then the phase current can be sampled to the B-phase or C-phase current at the window. In addition, the matching value of the SPWM control signal to be sampled needs to be modified, and Tmin / 2 width target insertion vectors are inserted before and after the SPWM signal that needs to be secondary frequency modulated, so as to compensate the SPWM signal after the secondary frequency modulation, so that the length of the SPWM output voltage vector is consistent with that of the original SPWM output voltage vector.

[0050] When the vector voltage is located at the low voltage modulation region, the three-phase SPWM edge difference is less than the ADC current sampling window width Tmin, and the phase current cannot be sampled. In this case, the secondary frequency modulation function needs to be performed on two-phase SPWM signals in two adjacent periods respectively to obtain a sampling window. In the first period, the secondary frequency modulation function of the B-phase SPWM is enabled, and the secondary frequency modulation functions of the A-phase and C-phase SPWM signals are closed, so that only the B-phase signal of the SPWM is ANDed with the IPWM signal, so as to obtain a sampling window with sufficient width. In addition, the matching value of the B-phase SPWM is modified, and Tmin / 2 width target insertion vectors are inserted before and after the SPWM output signal, so that the length of the SPWM output voltage vector is consistent with that of the original SPWM output voltage vector, and the B-phase current can be obtained by sampling at the trigger point. In the next period, only the secondary frequency modulation function of the C-phase SPWM is enabled, and the secondary frequency modulation functions of the A-phase and B-phase are closed, and Tmin / 2 width target insertion vectors are inserted before and after the output signal, so that the C-phase current can be obtained by sampling at the trigger point.

[0051] Figure 1 The single-resistor current sampling is used to reconstruct the unobserved region, including the sector edge and the low voltage modulation region, and the unobserved region cannot meet the requirement of the sampling window width because the SPWM edges are close.

[0052] Figure 2 A phase current reconstruction flowchart is given, according to the sampled SPWM output, the secondary frequency modulation of the SPWM output is performed by using the IPWM, and then waveform transformation is further performed to meet the requirement of the current sampling window width, and then the current reconstruction in the whole region is realized.

[0053] As shown in Figure 2 the secondary frequency modulation control method based on single-resistor sampling phase current reconstruction provided by the embodiment of the application comprises the following steps:

[0054] Step 1, get the SPWM signal to be sampled. The SPWM signal is a center-symmetric waveform, in the process of counting up, when the counter value matches the value, output high level, in the process of counting down, when the counter value matches the value, output low level, when the up-counting match value and the down-counting match value are the same, the SPWM output center-symmetric waveform. Similarly, the IPWM output center-symmetric waveform, the IPWM counter counts to the first match value, output low level, at the second match value, output high level, the low pulse width of the IPWM output waveform is the minimum value Tmin of the sampling width, the IPWM period is consistent with the SPWM period.

[0055] Step 2, according to the voltage value, the sector where the voltage vector is located is calculated, when the voltage vector is inside the sector, the width between the edges of the three-phase SPWM signal meets the ADC sampling requirement, in a SPWM period, the current of two phases can be normally sampled, and the current of another phase is calculated through the relationship of the phase currents, and the three-phase current reconstruction is completed according to the sector where the voltage vector is located.

[0056] Step 3, when the voltage vector is not inside the sector, it is judged whether the voltage vector is located at the sector edge or the low-voltage modulation area.

[0057] When the voltage vector is located at the sector edge, that is, the width between the edges of two-phase SPWM signals in the three-phase SPWM signal edge is less than the current sampling width, such as Sb and Sc signals in Figure 3 , at the sampling point 1, only the A-phase current can be sampled, and the three-phase current reconstruction cannot be completed. In this case, the Sc modulation function is enabled at the beginning of the SPWM period, the Sc signal is modulated twice by the IPWM (Im) signal, the Sc signal output becomes low in the low level interval of the IPWM output, at this time, the minimum sampling window can be met, at the sampling point 2, the C-phase current is sampled by triggering the ADC, because the secondary modulation will change the duty cycle of the SPWM signal, at this time, the match values of the up-counting and down-counting of the SPWM are reduced, so that the rising edge width and the falling edge width of the SPWM are expanded Tmin / 2, so that the duty cycle of the SPWM is not changed, and the voltage vector is not reduced, avoiding current distortion. In this way, the A-phase and C-phase currents can be sampled, and the three-phase current reconstruction is completed.

[0058] When the voltage vector is located in the low-voltage modulation area, that is, the width between the edges of the three-phase signals in the three-phase SPWM signal edge is less than the current sampling width Tmin, such as Figure 4In this case, the Sa, Sb, and Sc signals cannot sample the phase current, thus preventing three-phase current reconstruction. To solve this problem, in the first cycle of two consecutive SPWM cycles, the Sb modulation function is enabled at the beginning of the cycle, while the other two phase modulation functions are disabled. The Sb signal is then modulated secondary using the IPWM (Im) signal. The Sb signal becomes low during the low-level range of the IPWM output, satisfying the minimum ADC sampling window. At sampling point 3, the ADC samples the B-phase current. To avoid vector voltage loss, the B-phase SPWM matching value is modified, extending the SPWM rising and falling edge widths by Tmin / 2. Similarly, in the next adjacent SPWM cycle, the Sc modulation function is enabled at the beginning of the cycle, while the other two phase modulation functions are disabled. The Sc signal is then modulated secondary using the IPWM (Im) signal. The Sc signal becomes low during the low-level range of the IPWM output, satisfying the minimum ADC sampling window. At sampling point 4, the ADC samples the C-phase current. The C-phase SPWM matching value is modified, extending the SPWM rising and falling edge widths by Tmin / 2 to prevent voltage vector reduction. This allows for the sampling of two-phase currents, Ib and Ic, thus enabling the reconstruction of the three-phase current.

[0059] Step 4: Reconstruct the phase current based on the phase current sampling results.

[0060] Based on the same inventive concept as the above-described method embodiments, this invention also provides a secondary frequency modulation control device based on single-resistor sampling phase current reconstruction, such as... Figure 5 As shown, it includes:

[0061] The acquisition module is used to acquire the three-phase SPWM control signal of the sampling period. The SPWM control signal is output in center-aligned mode.

[0062] The region determination module is used to calculate the voltage vector and determine its region. This step calculates a reference voltage based on the output voltage, and then determines the output voltage sector based on the reference voltage. When the vector voltage is within the sector, the difference between the two-phase SPWM edges is greater than the ADC current sampling window width Tmin. The phase current is sampled at the trigger point, and the output phase current is calculated based on the sampled current and the output voltage sector.

[0063] The sector edge processing module is used to perform secondary modulation on the single-phase PWM signal when the voltage vector is located at the sector edge. It inserts half the width of the ADC current sampling window into the rising and falling edges of the PWM signal that requires secondary frequency modulation.

[0064] The low-voltage modulation area processing module is configured to perform secondary modulation on one of the phase PWM signals in the previous period when the voltage vector is in the low-voltage modulation area, and insert one-half of the ADC current sampling window width into the rising edge and the falling edge of the PWM signal that needs secondary frequency modulation, respectively, perform secondary modulation on another of the phase PWM signals in the adjacent next period, and insert one-half of the ADC current sampling window width into the rising edge and the falling edge of the PWM signal that needs secondary frequency modulation, respectively.

[0065] The device embodiment described above performs secondary modulation on the sampling SPWM signal by using the IPWM signal, adjusts the SPWM waveform at the sector edge and the low-voltage modulation area, completes the three-phase current reconstruction, solves the problem that the non-observation area of the single-resistor sampling phase current reconstruction cannot be sampled, and has small software overhead and does not introduce additional hardware cost through the hardware implementation control of the chip.

[0066] The device embodiment described above performs secondary modulation on the sampling SPWM signal by using the IPWM signal, adjusts the SPWM waveform at the sector edge and the low-voltage modulation area, completes the three-phase current reconstruction, solves the problem that the non-observation area of the single-resistor sampling phase current reconstruction cannot be sampled, and has small software overhead and does not introduce additional hardware cost through the hardware implementation control of the chip.

[0067] The device embodiment described above performs secondary modulation on the sampling SPWM signal by using the IPWM signal, adjusts the SPWM waveform at the sector edge and the low-voltage modulation area, completes the three-phase current reconstruction, solves the problem that the non-observation area of the single-resistor sampling phase current reconstruction cannot be sampled, and has small software overhead and does not introduce additional hardware cost through the hardware implementation control of the chip.

[0068] When the motor controller provided by the above embodiment is used to perform field vector control on the brushless direct-current motor or the permanent magnet synchronous motor, the method of performing secondary frequency modulation on the SPWM control signal by using the IPWM signal is used to realize the single-resistor sampling phase current reconstruction, which can improve the accuracy of current sampling and further improve the precision and efficiency of motor control.

[0069] The device embodiment described above performs secondary modulation on the sampling SPWM signal by using the IPWM signal, adjusts the SPWM waveform at the sector edge and the low-voltage modulation area, completes the three-phase current reconstruction, solves the problem that the non-observation area of the single-resistor sampling phase current reconstruction cannot be sampled, and has small software overhead and does not introduce additional hardware cost through the hardware implementation control of the chip.

[0070] It should be noted that the above multiple embodiments are only examples, and the technical solutions of each embodiment can be combined, which are all within the protection scope of the present application.

[0071] While embodiments of the application have been shown and described, it is to be understood that the embodiments described are merely exemplary of the principles and application of the present application. Numerous modifications and adaptions can be effected without departing from the spirit and scope of the present application, which is not limited to the exact construction and arrangement described. It is intended, therefore, to cover all modifications and adaptions that fall within the scope of the claims and their equivalents.

Claims

1. A secondary frequency modulation control method based on single-resistor sampling and phase current reconstruction, characterized in that, Suitable for scenarios with limited sampling windows when using low-cost current sampling, including: Calculate the ADC current sampling window width based on the ADC minimum sampling time and dead time; configure the IPWM channel output as the secondary frequency modulation signal, determine the IPWM matching value based on the sampling window width, so that the IPWM output pulse width is the same as the sampling window width, and the period is the same as the SPWM control signal period; configure the SPWM channel and IPWM channel modulation enable to control whether any SPWM channel performs an AND operation with the IPWM signal, so as to realize the secondary frequency modulation of the SPWM control signal; when the SPWM modulation enable is on and the IPWM output is high, the SPWM outputs according to its original signal; when the IPWM output is low, the SPWM output is low; when the SPWM modulation enable is off, the SPWM outputs according to its original signal. Obtain the PWM signal of the period to be sampled; Calculate the voltage vector and determine its region; When the voltage vector is located at the edge of the sector, the single-phase PWM signal modulation function is enabled at the beginning of the SPWM cycle. The single-phase PWM signal is modulated twice using the IPWM signal. Half of the ADC current sampling window width is inserted into the rising and falling edges of the PWM signal that requires secondary frequency modulation. When the voltage vector is in the low-voltage modulation region, the modulation function of one phase PWM signal is enabled at the beginning of the cycle. In the previous cycle, the one phase PWM signal is modulated twice, and half of the ADC current sampling window width is inserted at the rising and falling edges of the PWM signal that needs to be frequency-modulated twice. At the beginning of the next adjacent cycle, the modulation function of one phase PWM signal is enabled, the modulation function of the other phase PWM signal is modulated twice, and half of the ADC current sampling window width is inserted at the rising and falling edges of the PWM signal that needs to be frequency-modulated twice.

2. The secondary frequency modulation control method based on single-resistor sampling and phase current reconstruction according to claim 1, characterized in that, When the voltage vector is located inside the sector, phase current sampling is performed directly.

3. The secondary frequency modulation control method based on single-resistor sampling phase current reconstruction according to claim 2, characterized in that, Phase current reconstruction is performed based on the phase current sampling data obtained from the sector interior, sector edge, and low-voltage modulation region.

4. The secondary frequency modulation control method based on single-resistor sampling and phase current reconstruction according to claim 1, characterized in that, Acquiring the PWM signal of the period to be sampled includes: acquiring the three-phase SPWM control signal of the period to be sampled, wherein the SPWM control signal is output in center-aligned mode.

5. A secondary frequency modulation control device based on single-resistor sampling phase current reconstruction, used to implement the method of any one of claims 1-4, characterized in that, Suitable for scenarios with limited sampling windows when using low-cost current sampling, including: The acquisition module is used to acquire the PWM signal of the period to be sampled; The region determination module is used to calculate the voltage vector and determine its region. The sector edge processing module is used to perform secondary modulation on the single-phase PWM signal when the voltage vector is located at the sector edge. It inserts half the width of the ADC current sampling window into the rising and falling edges of the PWM signal that requires secondary frequency modulation. The low-voltage modulation zone processing module is used to perform secondary modulation on one phase of the PWM signal in the previous cycle when the voltage vector is in the low-voltage modulation zone, and to insert half the ADC current sampling window width into the rising and falling edges of the PWM signal that needs secondary frequency modulation. In the next adjacent cycle, it performs secondary modulation on the other phase of the PWM signal, and inserts half the ADC current sampling window width into the rising and falling edges of the PWM signal that needs secondary frequency modulation.

6. A motor controller, characterized in that, The system includes a memory and a processor, wherein the memory stores program instructions that are executed by the processor, and the processor invokes the program instructions to perform the steps of the secondary frequency modulation control method based on single-resistor sampling phase current reconstruction as described in any one of claims 1 to 4.

7. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by the processor, it implements the steps of the secondary frequency modulation control method based on single-resistor sampling phase current reconstruction as described in any one of claims 1 to 4.

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