Hybrid modulation method and device for single-resistor sampling, electronic equipment and storage medium

Abstract

The invention discloses a hybrid modulation method and device for single-resistor sampling, electronic equipment and a storage medium. The modulation method comprises the following steps: acquiring a modulation ratio, and when the modulation ratio is smaller than or equal to a first threshold value, performing modulation by adopting a space vector pulse width modulation (SVPWM) mode; when the modulation ratio is larger than the first threshold value and smaller than or equal to the second threshold value, a discontinuous pulse width modulation (DPWM) mode is adopted for modulation; when the modulation ratio is larger than a second threshold value, a DPWM mode is adopted for modulation; wherein when the modulation ratio is larger than the first threshold value and smaller than or equal to the second threshold value, the currents of the two effective space vectors are collected; when the modulation ratio is greater than a second threshold, the current of an effective space vector is collected. According to the technical scheme, the modulation mode can be dynamically adjusted according to the actual working condition, the switching loss is reduced, and the system efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of motor control technology, and in particular to a hybrid modulation method, apparatus, electronic device, and storage medium for single-resistor sampling. Background Technology

[0002] In the field of motor control, Space Vector Pulse Width Modulation (SVPWM) technology is widely used in various AC motor control systems due to its ability to achieve efficient decoupling control of motor torque and flux linkage. Reducing switching losses is crucial for improving the efficiency and reliability of motor drive systems and reducing heat dissipation costs. Discontinuous Pulse Width Modulation (DPWM) exhibits a significant advantage in reducing switching losses in many motor control scenarios because it can reduce the number of switching device cycles, making it a hot research and application area.

[0003] In the motor current sampling stage, single-resistor current sampling schemes are widely used to reduce hardware costs. This scheme requires current reconstruction to obtain three-phase current information. However, when combined with DPWM modulation, it cannot simultaneously meet the requirements of reducing switching losses and current reconstruction, resulting in low efficiency of the motor control system. Summary of the Invention

[0004] This invention provides a hybrid modulation method, apparatus, electronic device, and storage medium for single-resistor sampling, which reduces switching losses while enabling the reconstruction of three-phase current through single-resistor sampling, thereby improving system efficiency.

[0005] According to one aspect of the present invention, a hybrid modulation method for single-resistor sampling is provided, the modulation method comprising:

[0006] Obtain the modulation ratio;

[0007] When the modulation ratio is less than or equal to the first threshold, the space vector pulse width modulation (SVPWM) mode is used for modulation.

[0008] When the modulation ratio is greater than the first threshold and less than or equal to the second threshold, discontinuous pulse width modulation (DPWM) mode is used for modulation; wherein, when the modulation ratio is greater than the first threshold and less than or equal to the second threshold, the current of two effective space vectors is sampled.

[0009] When the modulation ratio is greater than the second threshold, DPWM mode is used for modulation; wherein, when the modulation ratio is greater than the second threshold, the current of an effective space vector is sampled.

[0010] Optionally, the first threshold is the boundary value at which the DPWM modulation mode cannot perform phase-shift sampling when the effective space vector length is less than the minimum sampling time, and the second threshold is the boundary value at which the DPWM modulation mode cannot perform phase-shift sampling when the duty cycle is less than the minimum sampling time.

[0011] Optionally, the first threshold Second threshold ;in, Refers to the minimum sampling window. , For window time, It is half the PWM cycle time.

[0012] Optionally, modulation using Space Vector Pulse Width Modulation (SVPWM) includes:

[0013] The first time length and the second time length are calculated based on the duty cycles of phases A, B, and C; where the first time length refers to the difference between the maximum duty cycle and the intermediate duty cycle among phases A, B, and C, and the second time length refers to the difference between the intermediate duty cycle and the minimum duty cycle among phases A, B, and C.

[0014] When the first time length is less than the minimum sampling window, the phase corresponding to the maximum duty cycle among phases A, B, and C is phase-shifted; or, when the second time length is less than the minimum sampling window, the phase corresponding to the minimum duty cycle among phases A, B, and C is phase-shifted; the currents of the two effective space vectors are sampled to obtain the first phase current and the second phase current; wherein the two effective space vectors are different effective space vectors.

[0015] Alternatively, when the first time length is greater than the minimum sampling window and the second time length is greater than the minimum sampling window, current sampling is performed on the currents of the two effective space vectors to obtain the first phase current and the second phase current.

[0016] According to Kirchhoff's current law, the third phase current is obtained through the first phase current and the second phase current.

[0017] Optionally, when the modulation ratio is greater than the first threshold and less than or equal to the second threshold, modulation is performed using discontinuous pulse width modulation (DPWM) mode, including:

[0018] Each phase modulation wave is clamped within one-third of the power frequency cycle, and the third time length is calculated; where the third time length refers to the difference in duty cycle of the non-clamped phase.

[0019] When the third time length is greater than the minimum sampling window, the current of the two effective space vectors is sampled to obtain the first phase current and the second phase current.

[0020] Alternatively, when the third time length is less than the minimum sampling window, the phase of the non-clamped phase is shifted, and the currents of the two effective space vectors are sampled to obtain the first phase current and the second phase current.

[0021] According to Kirchhoff's current law, the third phase current is obtained through the first phase current and the second phase current.

[0022] Optionally, when the modulation ratio is greater than the second threshold, modulation is performed using DPWM mode, including:

[0023] The current of an effective space vector is sampled to obtain the first phase current;

[0024] The second phase current is obtained by low-pass filtering the direct-axis current and quadrature-axis current of the motor and then performing an inverse coordinate transformation.

[0025] According to Kirchhoff's current law, the third phase current is obtained through the first phase current and the second phase current.

[0026] Optionally, the modulation method also includes overmodulation techniques;

[0027] The overmodulation technique includes:

[0028] Each phase modulation wave is clamped within one-third of the power frequency cycle. The fifth and sixth time lengths are calculated based on the third and fourth time lengths. The fifth and sixth time lengths are used for the non-clamped phase waveform. The fourth time length is the difference between the duty cycle of the clamped phase and the intermediate duty cycle. The intermediate duty cycle is the duty cycle of the larger duty cycle between the non-clamped phase and the non-clamped phase.

[0029] The current of an effective space vector is sampled to obtain the first phase current;

[0030] The second phase current is obtained by low-pass filtering the direct-axis current and quadrature-axis current of the motor and then performing an inverse coordinate transformation.

[0031] According to Kirchhoff's current law, the third phase current is obtained through the first phase current and the second phase current.

[0032] According to another aspect of the present invention, a hybrid modulation apparatus for single-resistor sampling is provided, the apparatus comprising:

[0033] Modulation ratio acquisition module, used to acquire the modulation ratio;

[0034] The control module is used to perform modulation in the space vector pulse width modulation (SVPWM) mode when the modulation ratio is less than or equal to the first threshold.

[0035] When the modulation ratio is greater than the first threshold and less than or equal to the second threshold, discontinuous pulse width modulation (DPWM) mode is used for modulation; wherein, when the modulation ratio is greater than the first threshold and less than or equal to the second threshold, the current of two effective space vectors is sampled.

[0036] When the modulation ratio is greater than the second threshold, DPWM mode is used for modulation; wherein, when the modulation ratio is greater than the second threshold, the current of an effective space vector is sampled.

[0037] According to another aspect of the present invention, an electronic device is provided, the electronic device comprising:

[0038] At least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores a computer program executable by the at least one processor, the computer program being executed by the at least one processor to enable the at least one processor to perform the modulation method in any embodiment of the present invention.

[0039] According to another aspect of the present invention, a computer-readable storage medium is provided, which stores computer instructions for causing a processor to execute and implement the modulation method in any embodiment of the present invention.

[0040] The technical solution of this invention selects different modulation modes based on the relationship between the modulation ratio and a first threshold and a second threshold. When the modulation ratio is less than or equal to the first threshold, SVPWM mode is used for modulation, which improves the stability of the output voltage. When the modulation ratio is greater than the first threshold and less than or equal to the second threshold, DPWM mode is used for modulation, which reduces switching losses and improves system efficiency. When the modulation ratio is greater than the second threshold, DPWM mode is used for modulation. When the modulation ratio is greater than the first threshold and less than or equal to the second threshold, the current of two effective space vectors can be sampled, and the three-phase current is reconstructed based on the current of the two effective space vectors and Kirchhoff's current law. When the modulation ratio is greater than the second threshold, the current of one effective space vector is sampled, and the three-phase current is reconstructed using a current compensation method and Kirchhoff's current law. The technical solution of this invention can dynamically adjust the modulation mode according to the actual operating conditions, realize the reconstruction of the three-phase current by single-unit sampling, reduce switching losses, and improve system efficiency.

[0041] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0042] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0043] Figure 1 A flowchart of a hybrid modulation method for single-resistor sampling provided in an embodiment of the present invention;

[0044] Figure 2 A schematic diagram of a PWM waveform provided in an embodiment of the present invention;

[0045] Figure 3 This is another schematic diagram of a PWM waveform provided in an embodiment of the present invention;

[0046] Figure 4 is a schematic diagram illustrating the relationship between modulation ratio and modulation mode according to an embodiment of the present invention;

[0047] Figure 5 A schematic diagram illustrating modulation using SVPWM mode, provided as an embodiment of the present invention;

[0048] Figure 6 A schematic diagram illustrating another modulation method using SVPWM mode provided in an embodiment of the present invention;

[0049] Figure 7 This is a schematic diagram illustrating another modulation method using SVPWM mode, provided as an embodiment of the present invention.

[0050] Figure 8 A schematic diagram illustrating modulation using DPWM mode, provided as an embodiment of the present invention;

[0051] Figure 9 A schematic diagram illustrating another modulation method using DPWM mode provided in an embodiment of the present invention;

[0052] Figure 10 A schematic diagram of vector synthesis provided for an embodiment of the present invention;

[0053] Figure 11 This is a schematic diagram illustrating another modulation method using DPWM mode, provided as an embodiment of the present invention.

[0054] Figure 12 This is a schematic diagram illustrating another modulation method using DPWM mode, provided as an embodiment of the present invention.

[0055] Figure 13 This is a schematic diagram of the structure of a hybrid modulation device for single-resistor sampling provided in an embodiment of the present invention;

[0056] Figure 14 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present invention. Detailed Implementation

[0057] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0058] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0059] Figure 1 This is a flowchart illustrating a hybrid modulation method for single-resistor sampling provided in an embodiment of the present invention. Figure 2 This is a schematic diagram of a PWM waveform provided in an embodiment of the present invention. Figure 3 Figure 4 is a schematic diagram of another PWM waveform provided in an embodiment of the present invention, illustrating the relationship between modulation ratio and modulation mode. The modulation method of this embodiment is applicable to scenarios where single-phase sampling is used to reconstruct the three-phase current of a motor, thereby reducing switching losses and improving system efficiency. The system can be a motor control system. Figure 1 As shown, the modulation method includes:

[0060] S110, Obtain the modulation ratio.

[0061] In this embodiment of the invention, the modulation ratio is the ratio of the output voltage vector amplitude to the maximum linear modulation voltage. The magnitude of the modulation ratio affects the motor's output capability and waveform quality. Switching between different modulation modes based on the modulation ratio can improve the motor's output capability and reduce switching losses. For example, the modulation ratio can be calculated based on the ratio of the output voltage vector amplitude to the maximum linear modulation voltage. When the signal is in the linear modulation region, the corresponding output voltage is: ,in, Maximum linear modulation voltage; modulation ratio When the signal is in the overmodulation region, the corresponding output voltage is: modulation ratio Maximum Overmodulation improves the utilization rate of the DC bus and reduces switching losses.

[0062] S120. When the modulation ratio is less than or equal to the first threshold, the space vector pulse width modulation (SVPWM) mode is used for modulation.

[0063] In this embodiment of the invention, the first threshold is the boundary value at which the minimum sampling window cannot collect the current of the effective space vector when the duty cycle of the PWM waveform is too large, such as... Figure 2 As shown, for example, if the duty cycle of phase A is 1, the duty cycle of phase B is 0.95, and the duty cycle of phase C is 0.95, regardless of the phase shift of phases B and C, the current effective space vector length n cannot be greater than or equal to the minimum sampling window. Therefore, it is impossible to collect the current of an effective space vector.

[0064] Space Vector Pulse Width Modulation (SVPWM) refers to a modulation method that can quickly track a reference command by adjusting the vector synthesis method in real time. The reference command is a pre-set or real-time calculated output voltage execution command signal. For example, in SVPWM mode, the sequence of vector synthesis (i.e., the combination order of effective space vectors and zero vectors) is adjusted in real time to concentrate harmonic energy near the switching frequency multiple, significantly reducing harmonic content, reducing losses, and ensuring the smooth operation of the motor. In SVPWM mode, the current of two effective space vectors can be collected, providing a basis for system control, protection, and performance optimization.

[0065] Typically, single-resistor sampling can only directly obtain the bus current, i.e., the inverter input current, and cannot directly obtain the three-phase motor current. The effective space vector corresponds to the conduction logic of the switching transistors. For example, effective space vector 100 corresponds to the upper bridge arm switch of phase A being on and the lower bridge arm switch of phase A being off; the upper bridge arm switch of phase B being off and the lower bridge arm switch of phase B being on; and the upper bridge arm switch of phase C being off and the lower bridge arm switch of phase C being on. Using single-phase sampling, a current signal with the same value as the phase A current can be collected. The phase A current can be reconstructed through the state of effective space vector 100. After current reconstruction, accurate three-phase current data is provided for motor control, so that the motor control system can accurately control the motor according to the operating conditions.

[0066] S130. When the modulation ratio is greater than the first threshold and less than or equal to the second threshold, the discontinuous pulse width modulation (DPWM) mode is used for modulation.

[0067] Specifically, when the modulation ratio is greater than the first threshold and less than or equal to the second threshold, the current of two effective space vectors is collected;

[0068] In this embodiment of the invention, the second threshold is the boundary value when the duty cycle of the non-clamped two-phase waveform is too small, and the current of two effective space vectors cannot be collected within the minimum sampling window, such as... Figure 3 As shown, for example, phase A has a duty cycle of 1, phase B has a duty cycle of 0.03, and phase C has a duty cycle of 0.03, with a minimum sampling window. With a duty cycle of 0.1, the duty cycle of phases B and C is less than the minimum sampling window. No matter how the phases of phases B and C move, only one effective space vector of current 100 can be collected.

[0069] Discontinuous pulse width modulation (DPWM) refers to a modulation method that keeps at least one phase of a three-phase inverter continuously on or off during each switching cycle. For example, controlling phase A clamping reduces the number of switching operations, thereby reducing switching losses and improving system efficiency. When the modulation ratio is greater than a first threshold and less than or equal to a second threshold, in DPWM mode, the currents of two effective space vectors can be sampled. Based on Kirchhoff's current law, the third-phase current can be obtained, thus enabling the reconstruction of the three-phase current and providing a basis for system control, protection, and performance optimization.

[0070] S140. When the modulation ratio is greater than the second threshold, DPWM mode is used for modulation.

[0071] Specifically, when the modulation ratio is greater than the second threshold, the current of an effective space vector is sampled.

[0072] In this embodiment of the invention, under DPWM mode, for example, when controlling phase A clamping with a phase A duty cycle of 1, when the modulation ratio is greater than the second threshold, the duty cycles of phases B and C will be smaller, resulting in a smaller sampling window. With a duty cycle of 0.1, the duty cycles of phases B and C are less than the minimum sampling window. Regardless of the phase shifts of phases B and C, only one effective space vector 100 of the current can be sampled. In DPWM mode, the first phase current is sampled based on one effective space vector 100. The second phase current is obtained by inverse coordinate transformation after low-pass filtering of the motor's direct-axis and quadrature-axis currents, and then the third phase current is obtained, providing a basis for system control, protection, and performance optimization.

[0073] The first threshold and the second threshold can be set according to the actual situation, such as according to the minimum sampling window, etc., and the present invention does not impose specific limitations.

[0074] Specifically, the modulation ratio is calculated by the ratio of the real-time output voltage vector amplitude to the maximum linear modulation voltage. The relationship between the modulation ratio *m* and the first and second thresholds is then determined, as shown in Figure 4. When the modulation ratio *m* is less than or equal to the first threshold, SVPWM mode is used for modulation, allowing the acquisition of current from two effective space vectors. When the modulation ratio *m* is greater than the first threshold and less than or equal to the second threshold, DPWM mode is used for modulation, acquiring the current from two effective space vectors. When the modulation ratio *m* is greater than the second threshold, DPWM mode is used for modulation, acquiring the current from one effective space vector. If the current from two effective space vectors is acquired, the first and second phase currents can be obtained, and the third phase current can be obtained according to Kirchhoff's current law. If the current from one effective space vector is acquired, the first phase current can be obtained, the second phase current can be obtained through current compensation, and the third phase current can be obtained according to Kirchhoff's current law. By selecting different modulation modes based on the relationship between the modulation ratio and the first and second thresholds, a suitable modulation mode can be selected according to the actual operating conditions, improving voltage utilization.

[0075] According to the technical solution of this invention, different modulation modes are selected based on the relationship between the modulation ratio and a first threshold and a second threshold. When the modulation ratio is less than or equal to the first threshold, SVPWM mode is used for modulation, which can improve the stability of the output voltage. When the modulation ratio is greater than the first threshold and less than or equal to the second threshold, DPWM mode is used for modulation, which can reduce switching losses and improve system efficiency. When the modulation ratio is greater than the second threshold, DPWM mode is used for modulation. When the modulation ratio is greater than the first threshold and less than or equal to the second threshold, the current of two effective space vectors can be sampled, and the three-phase current is reconstructed according to the current of the two effective space vectors and Kirchhoff's current law. When the modulation ratio is greater than the second threshold, the current of one effective space vector is sampled, and the three-phase current is reconstructed using a current compensation method and Kirchhoff's current law. The technical solution of this invention can dynamically adjust the modulation mode according to the actual operating conditions, realize the reconstruction of the three-phase current by single-unit sampling, reduce switching losses, and improve system efficiency.

[0076] Optionally, the first threshold is the boundary value at which the DPWM modulation mode cannot perform phase-shift sampling when the effective space vector length is less than the minimum sampling time, and the second threshold is the boundary value at which the DPWM modulation mode cannot perform phase-shift sampling when the duty cycle is less than the minimum sampling time.

[0077] In DPWM mode, when the modulation ratio is greater than the first threshold and less than or equal to the second threshold, the three-phase modulated wave is in a switching clamping state within the power frequency cycle, resulting in low switching losses. It can also acquire the current from two effective space vectors. Using the two-phase currents corresponding to these two effective space vectors, the third-phase current is obtained according to Kirchhoff's current law, achieving three-phase current reconstruction. When the motor is under light load (low modulation ratio), while DPWM mode can reduce switching losses, it cannot acquire the current from the effective space vectors, thus failing to perform current reconstruction and sacrificing output waveform quality. When the motor is under heavy load (high modulation ratio), DPWM mode can only acquire the current from one effective space vector, requiring current compensation methods for three-phase current reconstruction. Therefore, to ensure output waveform quality and reduce switching losses, determining the first and second thresholds and selecting an appropriate modulation mode based on the modulation ratio improves overall control efficiency.

[0078] Optionally, the first threshold Second threshold ;in, Refers to the minimum sampling window. , For window time, It is half the PWM cycle time.

[0079] In this context, the window time is a pre-defined time interval in the motor control algorithm where a specific action cannot be triggered or is only permitted to occur. For example, the window time can be the dead time plus the ringing time. The PWM cycle time is the smallest time unit for updating the state of the switching devices in the motor control algorithm. It is calculated according to a formula, for example, the first threshold is... Second threshold .

[0080] Figure 5 This is a schematic diagram illustrating modulation using SVPWM mode, provided as an embodiment of the present invention. Figure 6 This is a schematic diagram illustrating another modulation method using SVPWM mode, provided as an embodiment of the present invention. Figure 7 This is a schematic diagram illustrating another modulation method using SVPWM mode, provided as an embodiment of the present invention. In some embodiments, optionally, modulation using Space Vector Pulse Width Modulation (SVPWM) mode includes:

[0081] a1. Calculate the first time length and the second time length based on the duty cycles of phases A, B, and C; where the first time length refers to the difference between the maximum duty cycle and the intermediate duty cycle among phases A, B, and C, and the second time length refers to the difference between the intermediate duty cycle and the minimum duty cycle among phases A, B, and C.

[0082] For example, if the duty cycle of phase A is 0.75, the duty cycle of phase B is 0.5, and the duty cycle of phase C is 0.25, then the first time length T1 is... The second time length T2 is .

[0083] a2. When the first time length is less than the minimum sampling window, the phase corresponding to the maximum duty cycle among phases A, B, and C is phase-shifted; or, when the second time length is less than the minimum sampling window, the phase corresponding to the minimum duty cycle among phases A, B, and C is phase-shifted; the currents of the two effective space vectors are sampled to obtain the first phase current and the second phase current; wherein the two effective space vectors are different effective space vectors.

[0084] For example, such as Figure 5 As shown, the duty cycle of phase A is 0.75, the duty cycle of phase B is 0.75, and the duty cycle of phase C is 0.5. Therefore, the first time length T1 is... The second time length T2 is The first time length T1 is less than the minimum sampling time. Currently, only one valid spatial vector can be acquired. Therefore, phase shifting of phase A can be performed, which can be done by shifting phase A to the right by a length of... After phase shifting, the current of two valid space vectors can be sampled. For example, in the first minimum sampling window... The current of an effective space vector 110 is sampled within the second minimum sampling window. Based on the effective space vector 110, the first phase current -IC can be sampled. The current of another effective space vector 100 is collected internally, and the second phase current IA can be collected based on the effective space vector 100.

[0085] Or, such as Figure 6 As shown, the duty cycle of phase A is 0.75, the duty cycle of phase B is 0.5, and the duty cycle of phase C is 0.5. Therefore, the first time length T1 is... The second time length T2 is The second time length T2 is less than the minimum sampling time. Currently, only one valid space vector of current can be collected. Therefore, phase shifting of phase C is possible, such as shifting phase C to the left by a length of... After phase shifting, the current of two valid space vectors can be sampled. For example, in the first minimum sampling window... The current of an effective space vector 110 is sampled within the second minimum sampling window. Based on the effective space vector 110, the first phase current -IC can be sampled. The current of another effective space vector 100 is collected internally, and the second phase current IA can be collected based on the effective space vector 100.

[0086] a3. Alternatively, when the first time length is greater than the minimum sampling window and the second time length is greater than the minimum sampling window, current sampling is performed on the currents of the two effective space vectors to obtain the first phase current and the second phase current.

[0087] Specifically, when the duty cycle of phase A is 0.75, the duty cycle of phase B is 0.5, and the duty cycle of phase C is 0.25, the first time length T1 and the second time length T2 are both 0.25, the minimum sampling window is 0.1, and both the first and second time lengths are greater than the minimum sampling window. In this case, the current of two valid space vectors can be sampled. For example, as... Figure 7 As shown, in the first minimum sampling window The current of an effective space vector 110 is sampled within the second minimum sampling window. Based on the effective space vector 110, the first phase current -IC can be sampled. The current of another effective space vector 100 is collected internally, and the second phase current IA can be collected based on the effective space vector 100.

[0088] a4. According to Kirchhoff's current law, the third phase current is obtained through the first phase current and the second phase current.

[0089] For example, the third phase current IB is calculated using the first phase current -IC and the second phase current IA, where IB = 0 - IA - IC. Here, -IC represents the outflow of phase current IC, and IA represents the inflow of phase current IA. It should be noted that the first phase current can also be IA or IB, the second phase current can also be IC or IB, and the third phase current can also be IB or IA. The phase current obtained using the effective space vector acquired through the first minimum sampling window is the first phase current, the phase current obtained using the effective space vector acquired through the second minimum sampling window is the second phase current, and the phase current calculated using Kirchhoff's current law is the third phase current. This embodiment of the invention does not impose limitations on these aspects.

[0090] Figure 8 This is a schematic diagram illustrating modulation using DPWM mode, provided as an embodiment of the present invention. Figure 9 This is a schematic diagram illustrating another modulation method using DPWM mode, provided as an embodiment of the present invention. Figure 10 This is a schematic diagram of vector synthesis provided in an embodiment of the present invention. Figure 11 This is a schematic diagram illustrating another modulation method using DPWM mode provided in an embodiment of the present invention. Optionally, in some embodiments, when the modulation ratio is greater than a first threshold and less than or equal to a second threshold, modulation using discontinuous pulse width modulation (DPWM) mode includes:

[0091] b1. Control each phase modulation wave to clamp within one-third of the power frequency cycle, and calculate the third time length. The third time length refers to the difference in duty cycle between the non-clamped phases.

[0092] For example, when phase A is clamped, the duty cycle of phase A is 1, the duty cycle of phase B is 0.85, and the duty cycle of phase C is 0.85. Third time length .

[0093] b2. When the third time length is greater than the minimum sampling window, current sampling is performed on the currents of the two effective space vectors to obtain the first phase current and the second phase current.

[0094] For example, such as Figure 8 As shown, the duty cycle of phase A is 1, the duty cycle of phase B is 0.625, the duty cycle of phase C is 0.375, and the minimum sampling window... The third time length The third time length Larger than the minimum sampling window At this point, the current of two valid space vectors can be sampled. For example, in the first minimum sampling window... The current of an effective space vector 110 is sampled within the second minimum sampling window. Based on the effective space vector 110, the first phase current -IC can be sampled. The current of another effective space vector 100 is collected internally, and the second phase current IA can be collected based on the effective space vector 100.

[0095] b3. Alternatively, when the third time length is less than the minimum sampling window, the phase of the non-clamped phase is shifted, and the currents of the two effective space vectors are sampled to obtain the first phase current and the second phase current.

[0096] The duty cycle of phase A is 1, the duty cycle of phase B is 0.8, the duty cycle of phase C is 0.8, and the minimum sampling window is... The third time length The third time length Smaller than the minimum sampling window At this point, the current of one effective space vector can be sampled. By shifting the phase of phase B, the current of two effective space vectors can be sampled, for example, as shown below. Figure 9 As shown, in the first minimum sampling window The current of one effective space vector 101 is sampled. Based on the effective space vector 101, the second phase current -IB can be sampled within the second minimum sampling window. The current of another valid space vector 100 is collected internally, and the first phase current IA can be collected based on the valid space vector 100. For example... Figure 10As shown, after phase shifting, effective space vector 101 and effective space vector 110 are vector synthesized. When their time is equal, the length of the synthesized effective space vector remains unchanged, and its direction is the direction of the base vector 100.

[0097] Or, such as Figure 11 As shown, phases B and C can also be moved simultaneously; for example, phase B can be moved to the right and phase C to the left, allowing the current of two effective space vectors to be sampled. For example, in the first minimum sampling window... The current of an effective space vector 110 is sampled within the second minimum sampling window. Based on the effective space vector 110, the first phase current -IC can be sampled. The current of another effective space vector 100 is collected internally, and the second phase current IA can be collected based on the effective space vector 100. Optionally, phase C can also be moved, but this embodiment of the invention does not specifically limit this.

[0098] b4. According to Kirchhoff's current law, the third phase current is obtained through the first phase current and the second phase current.

[0099] For example, the third phase current IC is calculated using the first phase current -IB and the second phase current IA, where IC = 0 -IB -IA. Here, -IB represents the outflow of phase current IB, and IA represents the inflow of phase current IA. It should be noted that the first phase current can also be IA or IC, the second phase current can also be IC or IB, and the third phase current can also be IB or IA. The current of the effective space vector acquired through the first minimum sampling window is taken as the first phase current, the current of the effective space vector acquired through the second minimum sampling window is taken as the second phase current, and the phase current calculated using Kirchhoff's current law is taken as the third phase current. This embodiment of the invention does not impose limitations on these considerations.

[0100] Figure 12 This is another schematic diagram illustrating modulation using DPWM mode provided by an embodiment of the present invention. In some embodiments, optionally, when the modulation ratio is greater than a second threshold, modulation using DPWM mode includes:

[0101] c1. Sample the current of an effective space vector to obtain the first phase current.

[0102] like Figure 12 As shown, in the minimum sampling window Within this window, the duty cycles of phases B and C are too small, making it impossible to acquire the current of the two effective space vectors regardless of phase shifting. Therefore, only the first minimum sampling window is sampled. The current of the effective space vector within is sampled to obtain the current of an effective space vector 100, and the first phase current IA is collected based on the effective space vector 100.

[0103] c2. The second phase current is obtained by performing a coordinate inverse transformation after low-pass filtering of the direct-axis current and quadrature-axis current of the motor.

[0104] The direct-axis current Id and quadrature-axis current Iq of the motor are two orthogonal components obtained by mapping the three-phase stator currents IA, IB, and IC to the rotor synchronous rotating coordinate system through coordinate transformation. Coordinate transformation can include Clark transform and Park transform. Therefore, when it is impossible to collect the three-phase current, the direct-axis current Id and quadrature-axis current Iq can be low-pass filtered and current compensation performed to obtain the sampled current. For example, IA, IB, and IC can be obtained by low-pass filtering and inverse coordinate transformation of the direct-axis current Id and quadrature-axis current Iq. Inverse coordinate transformation can be the inverse Clark transform or the inverse Park transform.

[0105] For example, the formula for inverse coordinate transformation based on low-pass filtering of the motor's direct-axis current and quadrature-axis current is as follows:

[0106] ,

[0107] .

[0108] in, For the three-phase stator current in Composite projected current on the axis For the three-phase stator current in The composite projected current on the axis, IB or IC, can be used as the second phase current.

[0109] c3. According to Kirchhoff's current law, the third phase current is obtained through the first phase current and the second phase current.

[0110] The first phase current IA is obtained by sampling the current of the effective space vector 100. The second phase current IB is obtained by current compensation based on the direct axis current and quadrature axis current of the machine. Then, according to Kirchhoff's current law, the third phase current IC can be obtained.

[0111] According to the technical solution of the present invention, when the modulation ratio is greater than the second threshold, the first phase current is obtained by collecting the current of the effective space vector, the second phase current is obtained by the current compensation method, and the third phase current is obtained according to Kirchhoff's current law. This can ensure the continuity of the three-phase current feedback when the modulation ratio is too large, and improve the control effect on the motor.

[0112] Optionally, the modulation method also includes overmodulation techniques;

[0113] Overmodulation techniques include:

[0114] d1. Control each phase modulation wave to clamp within one-third of the power frequency cycle. Calculate the fifth and sixth time lengths based on the third and fourth time lengths. The fifth and sixth time lengths are used to generate the non-clamped phase waveform. The fourth time length is the difference between the duty cycle of the clamped phase and the intermediate duty cycle, and the intermediate duty cycle is the duty cycle of the larger duty cycle among the non-clamped phases.

[0115] For example, the fifth time length and the sixth time length The calculation formula is:

[0116] .

[0117] Where TS is the PWM period, which can be, for example, 1. Based on the fifth time length... and the sixth time length Regenerate the PWM waveform.

[0118] d2. Sample the current of an effective space vector to obtain the first phase current.

[0119] d3. The second phase current is obtained by performing a coordinate inverse transformation after low-pass filtering of the direct-axis current and quadrature-axis current of the motor.

[0120] d4. According to Kirchhoff's current law, the third phase current is obtained through the first phase current and the second phase current.

[0121] Figure 13 This is a schematic diagram of a hybrid modulation device for single-resistor sampling provided in an embodiment of the present invention, as shown below. Figure 13 As shown, the device includes:

[0122] The modulation ratio acquisition module M1 is used to acquire the modulation ratio;

[0123] Control module M2 is used to perform modulation in space vector pulse width modulation (SVPWM) mode when the modulation ratio is less than or equal to the first threshold.

[0124] When the modulation ratio is greater than the first threshold and less than or equal to the second threshold, discontinuous pulse width modulation (DPWM) mode is used for modulation; wherein, when the modulation ratio is greater than the first threshold and less than or equal to the second threshold, the current of two effective space vectors is sampled.

[0125] When the modulation ratio is greater than the second threshold, DPWM mode is used for modulation; wherein, when the modulation ratio is greater than the second threshold, the current of an effective space vector is sampled.

[0126] Figure 14 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present invention, such as... Figure 14The electronic device 10 shown includes:

[0127] At least one processor 11; and a memory communicatively connected to the at least one processor; wherein the memory stores a computer program executable by the at least one processor, the computer program being executed by the at least one processor to enable the at least one processor to perform the modulation method in any embodiment of the present invention.

[0128] Figure 14 A schematic diagram of an electronic device 10, which can be used to implement embodiments of the present invention, is shown. The electronic device is intended to represent various forms of digital computers, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device can also represent various forms of mobile devices, such as personal digital processors, cellular phones, smartphones, wearable devices (e.g., helmets, glasses, watches, etc.), and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely illustrative and are not intended to limit the implementation of the invention described and / or claimed herein.

[0129] like Figure 14 As shown, the electronic device 10 includes at least one processor 11 and a memory, such as a read-only memory (ROM) 12 or a random access memory (RAM) 13, communicatively connected to the at least one processor 11. The memory stores computer programs executable by the at least one processor. The processor 11 can perform various appropriate actions and processes based on the computer program stored in the ROM 12 or loaded from storage unit 18 into the RAM 13. The RAM 13 can also store various programs and data required for the operation of the electronic device 10. The processor 11, ROM 12, and RAM 13 are interconnected via a bus 14. An input / output (I / O) interface 15 is also connected to the bus 14.

[0130] Multiple components in electronic device 10 are connected to I / O interface 15, including: input unit 16, such as keyboard, mouse, etc.; output unit 17, such as various types of displays, speakers, etc.; storage unit 18, such as disk, optical disk, etc.; and communication unit 19, such as network card, modem, wireless transceiver, etc. Communication unit 19 allows electronic device 10 to exchange information / data with other devices through computer networks such as the Internet and / or various telecommunications networks.

[0131] Processor 11 can be a variety of general-purpose and / or special-purpose processing components with processing and computing capabilities. Some examples of processor 11 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various special-purpose artificial intelligence (AI) computing chips, various processors running machine learning model algorithms, a digital signal processor (DSP), and any suitable processor, controller, microcontroller, etc. Processor 11 performs the various methods and processes described above, such as the hybrid modulation method of single-resistor sampling.

[0132] In some embodiments, the hybrid modulation method for single-resistance sampling can be implemented as a computer program tangibly contained in a computer-readable storage medium, such as storage unit 18. In some embodiments, part or all of the computer program can be loaded and / or mounted on electronic device 10 via ROM 12 and / or communication unit 19. When the computer program is loaded into RAM 13 and executed by processor 11, one or more steps of the hybrid modulation method for single-resistance sampling described above can be performed. Alternatively, in other embodiments, processor 11 can be configured to perform the hybrid modulation method for single-resistance sampling by any other suitable means (e.g., by means of firmware).

[0133] Various embodiments of the systems and techniques described above herein can be implemented in digital electronic circuit systems, integrated circuit systems, field-programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), application-specific standard products (ASSPs), systems-on-a-chip (SoCs), payload-programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various embodiments may include implementations in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which may be a dedicated or general-purpose programmable processor, capable of receiving data and instructions from a storage system, at least one input device, and at least one output device, and transmitting data and instructions to the storage system, the at least one input device, and the at least one output device.

[0134] Computer programs used to implement the methods of the present invention may be written in any combination of one or more programming languages. These computer programs may be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, such that when executed by the processor, the computer programs cause the functions / operations specified in the flowcharts and / or block diagrams to be performed. The computer programs may be executed entirely on a machine, partially on a machine, or as a standalone software package, partially on a machine and partially on a remote machine, or entirely on a remote machine or server.

[0135] According to embodiments of the present invention, a computer-readable storage medium is also provided, which stores computer instructions for causing a processor to execute and implement the modulation method in any embodiment of the present invention.

[0136] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0137] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A hybrid modulation method of single-resistance sampling, characterized by, The modulation method comprises: acquiring a modulation ratio; when the modulation ratio is less than or equal to a first threshold value, modulating by using a space vector pulse width modulation (SVPWM) mode; when the modulation ratio is greater than the first threshold value and less than or equal to a second threshold value, modulating by using a discontinuous pulse width modulation (DPWM) mode; wherein when the modulation ratio is greater than the first threshold value and less than or equal to the second threshold value, the currents of two effective space vectors are collected; when the modulation ratio is greater than the second threshold value, modulating by using the DPWM mode; wherein when the modulation ratio is greater than the second threshold value, the current of one effective space vector is collected.

2. The modulation method of claim 1, wherein, The first threshold value is a boundary value at which the DPWM modulation mode cannot be phase-shifted when the length of the effective space vector is less than a minimum sampling time, and the second threshold value is a boundary value at which the DPWM modulation mode cannot be phase-shifted when the duty cycle is less than the minimum sampling time.

3. The modulation method of claim 2, wherein, The first threshold The second threshold ;in, Refers to the minimum sampling window. , For window time, It is half the PWM cycle time.

4. The modulation method of claim 1, wherein The modulation by using the SVPWM mode comprises: calculating a first time length and a second time length according to the duty cycles of the A phase, the B phase and the C phase; wherein the first time length refers to the difference between the maximum duty cycle and the intermediate duty cycle among the A phase, the B phase and the C phase, and the second time length refers to the difference between the intermediate duty cycle and the minimum duty cycle among the A phase, the B phase and the C phase; when the first time length is less than a minimum sampling window, performing phase shift on the phase corresponding to the maximum duty cycle among the A phase, the B phase and the C phase, or when the second time length is less than the minimum sampling window, performing phase shift on the phase corresponding to the minimum duty cycle among the A phase, the B phase and the C phase; sampling the currents of two effective space vectors to obtain a first phase current and a second phase current; wherein the two effective space vectors are different effective space vectors; or, when the first time length is greater than the minimum sampling window and the second time length is greater than the minimum sampling window, sampling the currents of the two effective space vectors to obtain the first phase current and the second phase current; obtaining a third phase current according to the first phase current and the second phase current based on the Kirchhoff's current law.

5. The modulation method of claim 1, wherein The modulation by using the DPWM mode when the modulation ratio is greater than the first threshold value and less than or equal to the second threshold value comprises: controlling each phase modulation wave to be clamped in one-third of a power frequency period, and calculating a third time length; wherein the third time length refers to the difference between the duty cycles of the non-clamped phases; when the third time length is greater than the minimum sampling window, sampling the currents of the two effective space vectors to obtain the first phase current and the second phase current; or, when the third time length is less than the minimum sampling window, performing phase shift on the non-clamped phases, and sampling the currents of the two effective space vectors to obtain the first phase current and the second phase current; obtaining a third phase current according to the first phase current and the second phase current based on the Kirchhoff's current law.

6. The modulation method of claim 1, wherein The modulation by using the DPWM mode when the modulation ratio is greater than the second threshold value comprises: sampling the current of one effective space vector to obtain a first phase current; According to the direct-axis current and the quadrature-axis current of the motor, a second phase current is obtained by low-pass filtering and coordinate inverse transformation; According to the Kirchhoff's current law, a third phase current is obtained by the first phase current and the second phase current.

7. The modulation method of claim 1, wherein The modulation method further comprises an overmodulation technique; The overmodulation technique comprises: The control of each phase modulation wave is clamped in one-third of the power frequency period, and the fifth time length and the sixth time length are calculated according to the third time length and the fourth time length; the fifth time length and the sixth time length are used to generate non-clamped phase waveforms; wherein the fourth time length is the difference between the clamped phase duty cycle and the intermediate duty cycle, and the intermediate duty cycle is the duty cycle of the larger one between the non-clamped phase duty cycles; Current sampling is performed on the current of one effective space vector to obtain a first phase current; According to the direct-axis current and the quadrature-axis current of the motor, a second phase current is obtained by low-pass filtering and coordinate inverse transformation; According to the Kirchhoff's current law, a third phase current is obtained by the first phase current and the second phase current.

8. A hybrid modulation device with single-resistor sampling, characterized by It comprises: A modulation ratio acquisition module is configured to acquire a modulation ratio; A control module is configured to adopt a space vector pulse width modulation (SVPWM) mode for modulation when the modulation ratio is less than or equal to a first threshold value; When the modulation ratio is greater than the first threshold value and less than or equal to a second threshold value, a discontinuous pulse width modulation (DPWM) mode is adopted for modulation; wherein the currents of two effective space vectors are collected when the modulation ratio is greater than the first threshold value and less than or equal to the second threshold value; When the modulation ratio is greater than the second threshold value, a DPWM mode is adopted for modulation; wherein the current of one effective space vector is collected when the modulation ratio is greater than the second threshold value.

9. An electronic device, comprising: The electronic device comprises: At least one processor; and a memory connected in communication with the at least one processor; wherein the memory stores a computer program executable by the at least one processor, and the computer program is executed by the at least one processor to enable the at least one processor to execute the modulation method of any one of claims 1-7.

10. A computer-readable storage medium, characterized in that, The computer readable storage medium stores computer instructions for enabling the processor to execute the modulation method of any one of claims 1-7 when executed.

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