Motor control method and air conditioner

Abstract

This application discloses a motor control method and an air conditioner, relating to the field of motor control. The motor control method is applied to a motor control device, which includes a first coordinate transformation module, a first current regulation module, a second current regulation module, a voltage synthesis module, an angle adjustment module, a second coordinate transformation module, and an inverter. The inverter is electrically connected to a first permanent magnet synchronous motor and a second permanent magnet synchronous motor. The motor control method regulates the current of the two motors, then synthesizes their respective converted voltages. The synthesized voltage control value is then transformed into coordinates using the second coordinate transformation module after angle conversion, and finally, the inverter controls the first and second permanent magnet synchronous motors. In this application, the synthesized voltage vector is adjusted to reduce the angular deviation between the corresponding voltage angles of the two motors, improving the synchronization loss phenomenon caused by excessive angular deviation.

Description

Technical Field

[0001] This application relates to the field of motor control, and more particularly to a motor control method and an air conditioner. Background Technology

[0002] With the continuous development of air conditioning systems, in applications where a single inverter drives multiple motors, permanent magnet synchronous motors (PMSMs) are widely used to drive core components such as compressors and indoor and outdoor fans in air conditioning systems due to their advantages such as high efficiency and energy saving, good speed regulation performance, high power density, high reliability and low electromagnetic interference.

[0003] Taking the control of a single-inverter dual permanent magnet synchronous motor as an example, a common control strategy is to use dual closed-loop control and dual-motor current synthesis technology to achieve master-slave motor control. In the dual closed-loop control, proportional-integral (PI) controllers in the speed and current loops are used to precisely regulate the speed and current parameters of each permanent magnet synchronous motor. The currents of the two permanent magnet synchronous motors are then synthesized through a complex voltage conversion process. Finally, the inverter controls the motor operation, achieving master-slave control of the dual permanent magnet synchronous motors.

[0004] The fundamental principle of permanent magnet synchronous motor (PMSM) operation is that the rotor speed and the stator rotating magnetic field speed must always remain synchronized. In a system where multiple PMSMs operate in tandem, a change in the load torque of any one PMSM will disrupt the original synchronization, causing the PMSM to lose synchronization. However, the dual-closed-loop control in the aforementioned control strategy is complex, has limited response speed, and is difficult to respond quickly and effectively to sudden changes in load torque. Summary of the Invention

[0005] This application provides a motor control method and an air conditioner that can effectively address the loss of synchronization phenomenon in permanent magnet synchronous motors caused by sudden changes in load torque and make timely adjustments.

[0006] In a first aspect, a motor control method is provided, which is applied to a motor control device. The motor control device includes a first coordinate transformation module, a voltage synthesis module, an angle adjustment module, a second coordinate transformation module, and an inverter. The inverter is electrically connected to a first permanent magnet synchronous motor and a second permanent magnet synchronous motor.

[0007] Motor control methods include:

[0008] The three-phase currents output from the first permanent magnet synchronous motor and the two permanent magnet synchronous motors are input to the first coordinate transformation module to obtain the actual values ​​of the first d-axis current, the first q-axis current, the second d-axis current, and the second q-axis current. The module also determines the first d-axis current command value and the first q-axis current command value corresponding to the actual values ​​of the first d-axis current and the first q-axis current, as well as the second d-axis current command value and the second q-axis current command value corresponding to the actual values ​​of the second d-axis current and the second q-axis current. These values, along with a preset setpoint, are input to the voltage synthesis module to obtain the combined d-axis voltage control value and the q-axis voltage control value. Finally, the first voltage angle corresponding to the first permanent magnet synchronous motor is... The angle of the first voltage corresponding to the second permanent magnet synchronous motor is increased and tends towards the angle of the composite voltage vector, and the first voltage angle corresponding to the second permanent magnet synchronous motor is decreased and tends towards the angle of the composite voltage vector. The composite voltage is determined by the d-axis voltage control value and the q-axis voltage control value. The actual values ​​of the first d-axis current, the first q-axis current, the second d-axis current, the second q-axis current, the d-axis voltage control value, the q-axis voltage control value, and the preset setpoint are input to the angle adjustment module to obtain the composite angle. The composite angle is used to indicate the coordinate transformation of the first coordinate transformation module and the second coordinate transformation module. The d-axis voltage control value and the q-axis voltage control value are input to the second coordinate transformation module. The signal output by the second coordinate transformation module is processed by the inverter to obtain the target AC signal. The target AC signal is used to control the first permanent magnet synchronous motor and the second permanent magnet synchronous motor.

[0009] During the control process of the first and second permanent magnet synchronous motors, the currents of the two motors are regulated, and their converted voltages are then synthesized. The synthesized voltage control values ​​(i.e., the d-axis voltage control values ​​and the q-axis voltage control values) are then transformed into coordinates using a second coordinate transformation module after the synthesized angle transformation. This transformation is then used to control the first and second permanent magnet synchronous motors via an inverter. The voltage vector corresponding to the synthesized voltage control values ​​is adjusted, and the dq-axis voltage vectors of the two permanent magnet synchronous motors are brought closer to the magnitude of the synthesized voltage vector. This reduces the angular deviation of the pressure components of the two motors on the d-axis, improving the synchronization problem caused by excessive angular deviations among the multiple permanent magnet synchronous motors.

[0010] In one possible implementation, the actual values ​​of the first d-axis current and the first q-axis current are input to the first current control module to obtain the first d-axis current command value and the first q-axis current command value. This includes: performing a limiting process on the actual value of the first d-axis current and the first d-axis current setpoint to obtain the first d-axis current command value. The limiting process is used to indicate that the first d-axis current command value is a preset value. The preset value is zero or N1, where N1 is a value determined based on the parameters and operating conditions of the first permanent magnet synchronous motor; and performing a selection process on the actual value of the first q-axis current and the first q-axis current setpoint to obtain the first q-axis current command value.

[0011] During startup, through The corresponding preset value for i d1 i q1 By making restrictions or selective adjustments, the corresponding permanent magnet synchronous motor can quickly establish a suitable magnetic field and torque, reducing start-up time and improving the dynamic performance of the device. Furthermore, after startup, current feedback is introduced to monitor the actual operating status of each permanent magnet synchronous motor in real time, enabling the motors to better adapt to different operating conditions and improving the stability and robustness of the device.

[0012] In one possible implementation, the actual values ​​of the second d-axis current and the second q-axis current are input to the second current control module to obtain the second d-axis current command value and the second q-axis current command value. This includes: performing a limiting process on the actual value of the second d-axis current and the given value of the second d-axis current to obtain the second d-axis current command value. The limiting process is used to indicate that the second d-axis current command value is a preset value, which is either zero or N2, where N2 is a value determined based on the parameters and operating conditions of the second permanent magnet synchronous motor; and performing a selection process on the actual value of the second q-axis current and the given value of the second q-axis current to obtain the second q-axis current command value.

[0013] During startup, through The corresponding preset value for i d2 i q2 By making restrictions or selective adjustments, the corresponding permanent magnet synchronous motor can quickly establish a suitable magnetic field and torque, reducing start-up time and improving the dynamic performance of the device. Furthermore, after startup, current feedback is introduced to monitor the actual operating status of each permanent magnet synchronous motor in real time, enabling the motors to better adapt to different operating conditions and improving the stability and robustness of the device.

[0014] In one possible implementation, the first d-axis current command value, the first q-axis current command value, the second d-axis current command value, the second q-axis current command value, and a preset setpoint are input to a voltage synthesis module to obtain the combined d-axis voltage control value and the q-axis voltage control value. This includes: inputting the first d-axis current command value, the first q-axis current command value, and the preset setpoint to the voltage synthesis module to obtain a first d-axis voltage reference value and a first q-axis voltage reference value; inputting the second d-axis current command value, the second q-axis current command value, and the preset setpoint to the voltage synthesis module to obtain a second d-axis voltage reference value and a second q-axis voltage reference value; and the voltage synthesis module performs a merging process on the first d-axis voltage reference value, the first q-axis voltage reference value, the second d-axis voltage reference value, and the second q-axis voltage reference value to obtain the d-axis voltage control value and the q-axis voltage control value.

[0015] This application provides a d-axis voltage control value u after merging processing. d and q-axis voltage control value u q Compared to related technologies that synthesize the currents of multiple motors, this inverter control method directly merges the voltages, eliminating the complexity of dual-loop control. Since the voltages of the two motors are directly synthesized and output to the inverter for control, the response is faster.

[0016] In one possible implementation, the voltage synthesis module performs a merging process on the first d-axis voltage reference value, the first q-axis voltage reference value, the second d-axis voltage reference value, and the second q-axis voltage reference value. This includes: processing the first d-axis voltage reference value, the first q-axis voltage reference value, the second d-axis voltage reference value, and the second q-axis voltage reference value to obtain the magnitude of the synthesized voltage vector; determining the angle of the synthesized voltage vector based on the first voltage angle and the second voltage angle, wherein the first voltage angle is determined by the first d-axis voltage reference value and the first q-axis voltage reference value, and the second voltage angle is determined by the second d-axis voltage reference value and the second q-axis voltage reference value; and determining the d-axis voltage control value and the q-axis voltage control value based on the magnitude and the angle of the synthesized voltage vector.

[0017] The specific process of the above synthesis treatment yields the d-axis voltage control value u after merging. d and q-axis voltage control value u q Controlling the inverter is done closer to the inverter, resulting in a faster response time.

[0018] In one possible implementation, the voltage synthesis module performs a merging process on the first d-axis voltage reference value, the first q-axis voltage reference value, the second d-axis voltage reference value, and the second q-axis voltage reference value, including:

[0019] The first d-axis voltage reference value, the first q-axis voltage reference value, the second d-axis voltage reference value, and the second q-axis voltage reference value are processed to obtain the magnitude of the composite voltage vector. The calculation process of the magnitude of the composite voltage vector is as follows:

[0020]

[0021] Among them, u d1 The first d-axis voltage reference value, u q1 The first q-axis voltage reference value, u d2 The second d-axis voltage reference value, u q2 The second q-axis voltage reference value, u m The magnitude of the synthesized voltage vector;

[0022] Based on the first d-axis voltage reference value and the first q-axis voltage reference value, the first voltage angle is determined. The calculation process for the first voltage angle is as follows:

[0023]

[0024] Where, θ u1 This is the first voltage angle;

[0025] Based on the second d-axis voltage reference value and the second q-axis voltage reference value, the second voltage angle is determined. The calculation process for the second voltage angle is as follows:

[0026]

[0027] Where, θ u2 This is the second voltage angle;

[0028] Based on the first voltage angle and the second voltage angle, the angle of the composite voltage vector is determined. The calculation process for the angle of the composite voltage vector is as follows:

[0029]

[0030] Where, θ m The angle of the synthesized voltage vector;

[0031] Based on the magnitude and angle of the synthesized voltage vector, the d-axis voltage control value and the q-axis voltage control value are determined. The calculation process for the d-axis voltage control value and the q-axis voltage control value is as follows:

[0032]

[0033] Among them, u d This is the d-axis voltage control value, u q This is the q-axis voltage control value.

[0034] The specific process of the above synthesis treatment yields the d-axis voltage control value u after merging. d and q-axis voltage control value u q Controlling the inverter is done closer to the inverter, resulting in a faster response time.

[0035] In one possible implementation, the voltage synthesis module includes a first voltage model unit, a second voltage model unit, and a voltage synthesis unit; a first d-axis current command value, a first q-axis current command value, and a preset setpoint are input to the first voltage model unit to obtain a first d-axis voltage reference value and a first q-axis voltage reference value; a second d-axis current command value, a second q-axis current command value, and a preset setpoint are input to the second voltage model unit to obtain a second d-axis voltage reference value and a second q-axis voltage reference value; the first d-axis voltage reference value, the first q-axis voltage reference value, the second d-axis voltage reference value, and the second q-axis voltage reference value are input to the voltage synthesis unit to obtain a d-axis voltage control value and a q-axis voltage control value.

[0036] The specific process of the above synthesis treatment yields the d-axis voltage control value u after merging. d and q-axis voltage control value u q Controlling the inverter is done closer to the inverter, resulting in a faster response time.

[0037] In one possible implementation, the actual values ​​of the first d-axis current, the first q-axis current, the second d-axis current, the second q-axis current, the d-axis voltage control value, the q-axis voltage control value, and a preset setpoint are input to the angle adjustment module to obtain a composite angle. This includes: inputting the actual values ​​of the first d-axis current, the first q-axis current, the d-axis voltage control value, the q-axis voltage control value, and the preset setpoint to the angle adjustment module to obtain a first observation frequency; inputting the actual values ​​of the second d-axis current, the second q-axis current, the d-axis voltage control value, the q-axis voltage control value, and the preset setpoint to the angle adjustment module to obtain a second observation frequency; and the angle adjustment module converts and synthesizes the first and second observation frequencies to obtain a composite angle.

[0038] The synthesized angle, serving as a shared rotor position, is used to indicate the coordinate transformation between the first and second coordinate transformation modules. The synthesized angle can accommodate the speed changes of both the first and second permanent magnet synchronous motors caused by load variations, thereby influencing the first d-axis current command value i′. d1 First q-axis current command value i′ q1 The second d-axis current command value i′ d2 Second q-axis current command value i′ q2 d-axis voltage control value u d and q-axis voltage control value u q Adjustments will be made.

[0039] When the load torque of the first or second permanent magnet synchronous motor changes, the corresponding d-axis voltage reference value of the motor will change, causing the combined voltage vector of the d-axis voltage reference value and the q-axis voltage reference value to shift towards the d-axis voltage control value u. d and q-axis voltage control value u q The corresponding composite voltage vector u m By bringing them closer together, the angle deviation is reduced, that is, the angle between the combined voltage vector of the first permanent magnet synchronous motor and the combined voltage vector of the second permanent magnet synchronous motor is reduced, thereby improving the step loss phenomenon caused by excessive angle deviation of multiple permanent magnet synchronous motors.

[0040] In one possible implementation, the angle adjustment module includes a first phase-locked loop (PLL), a second PLL, a speed synthesis unit, and an angle calculation unit. The actual values ​​of the first d-axis current, the first q-axis current, the d-axis voltage control value, the q-axis voltage control value, and a preset setpoint are input to the first PLL to obtain a first observation frequency. The actual values ​​of the second d-axis current, the second q-axis current, the d-axis voltage control value, the q-axis voltage control value, and the preset setpoint are input to the second PLL to obtain a second observation frequency. The first and second observation frequencies are input to the speed synthesis unit to obtain a synthesized observation frequency. The synthesized observation frequency is input to the angle calculation unit to obtain a synthesized angle.

[0041] The first and second phase-locked loops are sensorless phase-locked loops. In the vector control of permanent magnet synchronous motors, accurate rotor position and speed are required for precise motor control. Sensorless phase-locked loops can estimate rotor position and speed by observing signals such as the motor's back electromotive force, thus replacing traditional position sensors, reducing system cost, and improving system reliability and adaptability.

[0042] Secondly, a motor control device is provided, including a unit for performing any of the methods in the first aspect. This device may be a terminal device or a chip within a terminal device.

[0043] Thirdly, a computer-readable storage medium is provided, which stores a computer program that, when run by a motor control device, causes the motor control device to perform any of the motor control methods in the first aspect.

[0044] Fourthly, a computer program product is provided, comprising: a computer program that, when run by a motor control device, causes the motor control device to execute any of the motor control methods described in the first aspect.

[0045] Fifthly, an air conditioner is provided, comprising an indoor unit, an outdoor unit, and a motor control device, wherein the motor control device is used to execute the motor control method of any one of the first aspects; the outdoor unit comprises M fans, wherein the motor control device is used to control the M fans, where M is a positive integer greater than 1.

[0046] It is understood that the beneficial effects of the second to fifth aspects mentioned above can be found in the relevant descriptions in the first aspect mentioned above, and will not be repeated here. Attached Figure Description

[0047] Figure 1 This application provides a schematic diagram of the structure of an outdoor unit for an air conditioner, as shown in an embodiment.

[0048] Figure 2 This paper illustrates a schematic diagram of the fan control architecture in an outdoor unit of an air conditioner, according to an embodiment of this application.

[0049] Figure 3 A schematic diagram of the structure of a motor control device provided in an embodiment of this application is shown;

[0050] Figure 4 This paper shows a schematic diagram of the structure of the motor control device provided in an embodiment of the present application for controlling multiple permanent magnet synchronous motors;

[0051] Figure 5 This paper shows a schematic diagram of the structure of another motor control device provided in an embodiment of the present application;

[0052] Figure 6 This paper shows a schematic diagram of the structure for determining the three-phase current of a permanent magnet synchronous motor in a motor control device provided in an embodiment of this application.

[0053] Figure 7 This paper shows a schematic diagram of the structure of the three-phase current reconfiguration module in the motor control device provided in an embodiment of this application;

[0054] Figure 8 A schematic diagram of the voltage synthesis unit in the motor control device provided in this application embodiment is shown;

[0055] Figure 9 This paper shows a schematic diagram of voltage synthesis in the motor control device provided in an embodiment of this application;

[0056] Figure 10 This paper shows a schematic diagram of the structure of an angle adjustment module in a motor control device provided in an embodiment of this application;

[0057] Figure 11 This paper shows a schematic diagram of the structure of another angle adjustment module in the motor control device provided in an embodiment of this application;

[0058] Figure 12 This paper shows a schematic diagram of the structure of another motor control device provided in an embodiment of the present application;

[0059] Figure 13 This paper shows a schematic diagram illustrating an example of increasing the load torque of the first permanent magnet synchronous motor in the motor control device provided in an embodiment of this application, showing an angle adjustment.

[0060] Figure 14 This paper shows a schematic diagram of the angle adjustment for reducing the load torque of the second permanent magnet synchronous motor in the motor control device provided in an embodiment of this application;

[0061] Figure 15 A schematic flowchart of a motor control method provided in an embodiment of this application is shown. Detailed Implementation

[0062] The technical solutions in the embodiments of this application will now be described with reference to the accompanying drawings.

[0063] It should be understood that "multiple" as mentioned in this application refers to two or more. In the description of this application, unless otherwise stated, " / " indicates "or," for example, A / B can mean A or B; "and / or" in this document is merely a description of the relationship between related objects, indicating that three relationships can exist, for example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Furthermore, to facilitate a clear description of the technical solutions of this application, the terms "first," "second," etc., are used to distinguish identical or similar items with essentially the same function and effect. Those skilled in the art will understand that the terms "first," "second," etc., do not limit the quantity or execution order, and that "first," "second," etc., do not necessarily imply differences.

[0064] References to "one embodiment" or "some embodiments" in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. Furthermore, the terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0065] To better understand the embodiments of this application, the terms or concepts that may be involved in the embodiments are explained below.

[0066] (1) Permanent magnet synchronous motor

[0067] Permanent magnet synchronous motors (PMSMs) are widely used in various fields for driving applications due to their advantages such as high efficiency and energy saving, good speed regulation performance, high reliability, and environmental friendliness. For example, in air conditioning systems, PMSMs can achieve precise temperature control and energy-saving operation; in new energy vehicles, PMSMs provide strong power output, improving driving range and acceleration performance; and in the field of industrial automation, they help robots accurately complete complex movements and enable CNC machine tools to achieve high-precision machining.

[0068] A permanent magnet synchronous motor (PMSM) consists of a stator and a rotor. The fundamental principle of its operation is that the rotor speed is always synchronized with the speed of the stator's rotating magnetic field. During operation, a three-phase current is applied to the stator windings to generate a rotating magnetic field, while the rotor establishes a constant magnetic field using permanent magnets. Based on the principle of electromagnetic induction, the interaction between the stator's rotating magnetic field and the rotor's permanent magnet magnetic field produces electromagnetic torque, ensuring that the rotor speed remains synchronized with the stator's rotating magnetic field speed. This synchronous characteristic is the key difference between PMSMs and asynchronous motors.

[0069] Before providing a detailed explanation of the motor control method and air conditioner provided in the embodiments of this application, the application scenarios and related technologies of the motor control method and air conditioner will be explained first.

[0070] In air conditioning systems, core components such as compressors and indoor / outdoor fans are all driven by electric motors. In related technologies, each drive motor is equipped with an independent inverter. Taking the outdoor unit fan as an example, outdoor units often have multiple fans. These fans work together to enhance heat dissipation and adapt to different operating conditions. While an independent inverter for each drive motor allows for precise control, it also presents several drawbacks: each inverter requires independent cooling, filtering, and protection circuits, leading to complex wiring and significant space requirements; furthermore, the combined switching losses and standby losses of the inverter result in a decrease in overall efficiency.

[0071] To improve energy efficiency and simplify system architecture, a single inverter driving multiple motors solution has emerged. Induction motors, because their rotor speed is always slightly lower than the speed of the stator's rotating magnetic field, exhibit slip, which gives them the ability to automatically adapt to load changes. When the load increases, the rotor speed decreases, the slip increases, and the rotor induced current and electromagnetic torque increase accordingly, ensuring stable motor operation and preventing step loss. Based on this, multiple motors can be connected in parallel through voltage-frequency ratio control, achieving the goal of a single inverter driving multiple induction motors. However, this solution has limitations: induction motors are large and inefficient, making it difficult to meet the increasingly stringent energy consumption standards in the air conditioning industry.

[0072] Permanent magnet synchronous motors have stood out in application scenarios such as driving compressors and indoor and outdoor fans in air conditioning systems due to their significant advantages such as high efficiency and energy saving, excellent speed regulation performance, high power density, high reliability and low electromagnetic interference. Single inverters driving multiple permanent magnet synchronous motors have been widely used.

[0073] Taking the use of a single inverter to drive multiple permanent magnet synchronous motors to drive the outdoor unit fan of an air conditioner as an example, the outdoor unit is often equipped with multiple fans, such as two fans, four fans, etc.

[0074] Figure 1 This application provides a schematic diagram of the structure of an outdoor unit for an air conditioner, as shown in an embodiment. Figure 2 The illustration shows a schematic diagram of the fan control architecture in an outdoor unit of an air conditioner according to an embodiment of this application, taking an outdoor unit of an air conditioner equipped with two fans as an example.

[0075] like Figure 1 The outdoor unit 10 of the air conditioner is equipped with a first fan 11 and a second fan 12.

[0076] like Figure 2 As shown, the inverter 30 acts as a power conversion device, converting DC power into three-phase current to supply power to the first permanent magnet synchronous motor 21 and the second permanent magnet synchronous motor 22. The first permanent magnet synchronous motor 21 drives the first fan 11 to operate, and the second permanent magnet synchronous motor 22 drives the second fan 12 to operate. For each permanent magnet synchronous motor, the stator has three-phase windings. When the three-phase current flows into the stator windings, a rotating magnetic field is generated. The rotor is equipped with permanent magnets, which generate a constant magnetic field. According to the principle that like poles repel and unlike poles attract, the rotating magnetic field of the stator interacts with the magnetic field of the rotor permanent magnet, causing the rotor to rotate synchronously with the stator magnetic field, realizing the conversion of electrical energy into mechanical energy and driving the fan to operate.

[0077] In related technologies, taking the control of dual permanent magnet synchronous motors with a single inverter as an example, a common control strategy is to use dual closed-loop control and dual-motor current synthesis technology to achieve master-slave motor control. Specifically, in dual closed-loop control, proportional-integral (PI) controllers in the speed and current loops are needed to precisely regulate the speed and current parameters of each permanent magnet synchronous motor. The currents of the two permanent magnet synchronous motors are then synthesized through a complex voltage conversion process, and finally, the inverter controls the motor operation to achieve master-slave control of the dual permanent magnet synchronous motors.

[0078] In a system with a single inverter and multiple permanent magnet synchronous motors operating in tandem, each permanent magnet synchronous motor maintains synchronous operation under ideal conditions. At this time, the frequency of the AC power output from the inverter is precisely matched with the rotational frequency of the motor rotor, and the rotating magnetic field generated by the motor stator interacts with the magnetic field of the rotor permanent magnet, maintaining a stable torque output.

[0079] However, when the load torque of any permanent magnet synchronous motor changes, the original synchronization state is broken, leading to a loss of synchronization. Taking the motor control of multiple fans in an air conditioner outdoor unit as an example, if the blades of a fan are entangled with foreign objects, the airflow resistance of each fan is different, or the blades of a fan are frosted during cooling, the load torque of the corresponding permanent magnet synchronous motor will suddenly increase. At this time, the resistance on the motor rotor increases, and the electromagnetic torque cannot be increased significantly in an instant to balance this change, so the rotor speed begins to decrease.

[0080] However, the inverter's output frequency does not automatically adjust in a short period, causing the rotational speed of the stator's rotating magnetic field to become out of sync with the rotor's speed. The stator's rotating magnetic field rotates at its original speed, while the rotor lags behind, and the angle difference between them gradually increases. When this angle difference exceeds a certain range, the motor's electromagnetic torque characteristics deteriorate, further exacerbating the rotor speed drop, ultimately leading to a loss of synchronism in the permanent magnet synchronous motor. Once this loss of synchronism occurs, the motor will face problems such as output torque fluctuations, increased vibration and noise, overheating, and even winding damage. It will also affect other motors through electrical coupling and mechanical linkage, disrupting system stability and reducing efficiency and reliability.

[0081] Among the common control strategies mentioned above, dual closed-loop control is complex, has limited response speed, and is difficult to respond quickly and effectively to changes in load torque.

[0082] In view of this, embodiments of this application provide a motor control method and an air conditioner. The motor control method is applied to a motor control device and an air conditioner. The motor control device is used to control a first permanent magnet synchronous motor and a second permanent magnet synchronous motor, and includes a first coordinate transformation module, a first current regulation module, a second current regulation module, a voltage synthesis module, an angle adjustment module, a second coordinate transformation module, and an inverter. The inverter is electrically connected to the first permanent magnet synchronous motor and the second permanent magnet synchronous motor. The motor control method inputs the three-phase currents output from the first permanent magnet synchronous motor and the second permanent magnet synchronous motor to the first coordinate transformation module to obtain the actual values ​​of the first d-axis current, the first q-axis current, the second d-axis current, and the second q-axis current after coordinate transformation. The first current regulation module regulates the actual values ​​of the first d-axis current and the first q-axis current, and the second current regulation module regulates the actual values ​​of the second d-axis current and the second q-axis current. Combined with preset values, a voltage synthesis module performs current-to-voltage conversion and voltage synthesis to obtain the d-axis voltage control value and the q-axis voltage control value. The outputs of the first coordinate transformation module and the voltage synthesis module are then used to obtain the synthesis angle for coordinate transformation by the angle adjustment module. Finally, the signal output from the second coordinate transformation module controls the first and second permanent magnet synchronous motors.

[0083] The motor control method provided in this application embodiment regulates the current of the first permanent magnet synchronous motor and the second permanent magnet synchronous motor during the control process, and then synthesizes the converted voltages of the two motors. The synthesized voltage control value (i.e., the d-axis voltage control value and the q-axis voltage control value) is then transformed into coordinates by a second coordinate transformation module after synthesizing the angle. The first permanent magnet synchronous motor and the second permanent magnet synchronous motor are then controlled by an inverter. The voltage vector corresponding to the synthesized voltage control value is adjusted to reduce the angle deviation between the corresponding angles of the two motors and improve the step loss phenomenon caused by excessive angle deviation of multiple permanent magnet synchronous motors.

[0084] The embodiments of this application will be illustrated below with reference to the accompanying drawings and through several exemplary embodiments. Figure 3 A schematic diagram of the structure of a motor control device provided in an embodiment of this application is shown, as follows: Figure 3 As shown, the motor control device is used to control the first permanent magnet synchronous motor 21 and the second permanent magnet synchronous motor 22. The first permanent magnet synchronous motor 21 is in Figure 3 The corresponding symbol is PMSM1, and the second permanent magnet synchronous motor 22 is in Figure 3 The corresponding symbol is PMSM2. The motor control device 400 includes a first coordinate transformation module 410, a first current regulation module 420, a second current regulation module 430, a voltage synthesis module 440, an angle adjustment module 450, a second coordinate transformation module 460, and an inverter 470. The inverter 470 is electrically connected to the first permanent magnet synchronous motor 21 and the second permanent magnet synchronous motor 22.

[0085] It should be noted that, Figure 3 The connections between the modules shown are merely illustrative and do not constitute a limitation on the connections between the modules in the motor control device. In other embodiments of this application, the motor control device may include... Figure 3 The components shown may include more or fewer components, or the motor control device may include... Figure 3 The components shown may be a combination of certain components, or the motor control device may include... Figure 3 Some of the components shown are sub-components of other components. Each component can be implemented in hardware, software, or a combination of both.

[0086] Furthermore, the first permanent magnet synchronous motor 21 and the second permanent magnet synchronous motor 22 can both represent a permanent magnet synchronous motor of one quantity, or a permanent magnet synchronous motor of M quantity, where M is a positive integer greater than 1. This application embodiment does not impose any restrictions on this.

[0087] It should be understood that the motor control device also includes a control module, which is used to implement software control of the first permanent magnet synchronous motor and the second permanent magnet synchronous motor by the motor control device. In other words, the control module is used to execute the motor control method proposed in the embodiments of this application.

[0088] The first coordinate transformation module 410 is used to convert the three-phase current output by the first permanent magnet synchronous motor 21 into the actual values ​​of the first d-axis current and the first q-axis current in the rotating coordinate system, and to convert the three-phase current output by the second permanent magnet synchronous motor 22 into the actual values ​​of the second d-axis current and the second q-axis current in the rotating coordinate system.

[0089] It should be understood that a permanent magnet synchronous motor (PMSM) generates electromagnetic torque based on the interaction between the magnetic field generated by the permanent magnet and the magnetic field generated by the current in the stator windings, thus driving the motor rotor to rotate. The first coordinate transformation module 410 can convert the complex three-phase stationary coordinate system with multiple variables and strong coupling into a two-phase rotating coordinate system, which facilitates field-oriented control and allows for precise control of the excitation magnetic field and electromagnetic torque. At the same time, the motor parameters are stable and clearly correlated with the operating state in this coordinate system, which is conducive to adjusting and optimizing the control parameters according to the actual working conditions. This leads to good dynamic and steady-state performance of the PMSM under different conditions, thereby improving efficiency.

[0090] In other words, the first coordinate transformation module 410 transforms the three-phase current i output by the first permanent magnet synchronous motor 21 into... u1 i v1 i w1 Converted to d-axis current in a rotating coordinate system, i.e., the actual value i of the first d-axis current. d1 and the q-axis current, i.e., the actual value of the first q-axis current i q1 ; and the three-phase current i output by the second permanent magnet synchronous motor 22 u2 i v2 i w2 Converted to the d-axis current in a rotating coordinate system, i.e., the actual value i of the second d-axis current. d2 and the q-axis current, i.e., the actual value of the second q-axis current i q2 .

[0091] The conversion of three-phase currents into direct-axis currents (d-axis currents) and quadrature-axis currents (q-axis currents) in a rotating coordinate system can be achieved through the Clark Transform, also known as the Clark transformation, which transforms the three-phase stationary coordinate system into a two-phase stationary coordinate system (αβ coordinate system). Then, the Park Transform, also known as the Park transformation, transforms the two-phase stationary coordinate system (αβ coordinate system) into a two-phase rotating coordinate system (dq coordinate system). In motor control, although the number of variables is reduced after the Clark transformation, coupling still exists. The Park transformation further transforms the variables from the stationary coordinate system to the rotating coordinate system, enabling decoupled control of the motor's electromagnetic torque and flux linkage under specific control strategies (such as field-oriented control), simplifying the motor control algorithm.

[0092] The first current regulation module 420 is used to adjust the actual value of the first d-axis current i d1 With the first d-axis current given value The process is performed to obtain the first d-axis current command value i′. d1 ; and input the actual value of the first q-axis current into i q1 With the first q-axis current given value The process is performed to obtain the first q-axis current command value i′. q1 .

[0093] The second current regulation module 430 is used to adjust the actual value of the second d-axis current i d2 With the second d-axis current given value The process is performed to obtain the second d-axis current command value i′. d2 ; and input the actual value of the second q-axis current into i q2 With the second q-axis current given value The process is performed to obtain the second q-axis current command value i′. q2 .

[0094] The processing in the first current control module 420 and the second current control module 430 includes restriction processing or selection processing. Restriction processing limits the current command value to the current setpoint value, while selection processing analyzes the current command value and the actual current value and selects the current command value or the actual current value as the current setpoint value.

[0095] Wherein, the first d-axis current setpoint First q-axis current given value The preset value is set during the startup process of the motor control device; the second d-axis current setpoint. Second q-axis current given value It is also a preset value set during the startup process of the motor control device.

[0096] It should be noted that permanent magnet synchronous motors are mainly divided into surface-mounted permanent magnet synchronous motors and embedded permanent magnet synchronous motors according to the way the permanent magnets are installed on the rotor.

[0097] In a surface-mount permanent magnet synchronous motor, the permanent magnets are directly attached to the surface of the rotor core. Because the permanent magnets are attached to the rotor surface, the direct-axis inductance L of the motor is... q and cross-axis inductance L q They are approximately equal, i.e., L d ≈L q In this case, the electromagnetic torque of the motor is mainly generated by the permanent magnets, and the reluctance torque is zero. Therefore, surface-mounted permanent magnet synchronous motors typically do not use maximum torque per ampere (MTPA) control, but instead employ a control strategy with zero direct-axis current. Under this strategy, the stator current is entirely used to generate quadrature-axis torque, making the current and torque linearly related. This approach simplifies control, achieves better dynamic performance, and simultaneously enables unity power factor operation, thus improving motor efficiency.

[0098] In an embedded permanent magnet synchronous motor, the permanent magnets are embedded inside the rotor, resulting in different magnetic reluctances along the direct and quadrature axes of the motor. Typically, the direct-axis inductance L... d Less than the quadrature axis inductance L q L d <L q This inductance difference causes the motor to generate reluctance torque in addition to permanent magnet torque during operation. The two torques work together to produce electromagnetic torque. Due to the presence of reluctance torque, the maximum torque-to-current ratio (MTPA) control strategy is often used. By reasonably adjusting the magnitude and ratio of the direct-axis current and quadrature-axis current, the reluctance torque is fully utilized to achieve maximum torque output at a given current, thereby improving the motor's operating efficiency and performance.

[0099] Therefore, if the first permanent magnet synchronous motor and the second permanent magnet synchronous motor are surface-mounted permanent magnet synchronous motors, That is, the default value is 0.

[0100] If the first permanent magnet synchronous motor and the second permanent magnet synchronous motor are embedded permanent magnet synchronous motors The preset values ​​are N1 and N2; N1 and N2 are small values ​​close to zero. The value of N1 is determined by calculation or experiment based on the specific parameters and operating conditions of the first permanent magnet synchronous motor, and the value of N2 is determined by calculation or experiment based on the specific parameters and operating conditions of the second permanent magnet synchronous motor, in order to achieve the optimal torque-to-current ratio. In some embodiments, if the first and second permanent magnet synchronous motors are the same type of permanent magnet synchronous motor, N1 = N2 = N, that is, the preset value is N.

[0101] In some embodiments, if the first permanent magnet synchronous motor is an embedded permanent magnet synchronous motor and the second permanent magnet synchronous motor is a surface-mounted permanent magnet synchronous motor... If the first permanent magnet synchronous motor is a surface-mounted permanent magnet synchronous motor and the second permanent magnet synchronous motor is an embedded permanent magnet synchronous motor...

[0102] The first current regulation module 420 and the second current regulation module 430 control current differently from the current loop in related technologies. In this embodiment, the first current regulation module 420 and the second current regulation module 430 control current during startup. The corresponding preset value for i d1 i q1 i d2 i q2 Adjustments are made to enable the corresponding permanent magnet synchronous motor to quickly establish a suitable magnetic field and torque. This rapid response at startup reduces startup time and improves the dynamic performance of the device. Furthermore, after startup, current feedback is introduced to monitor the actual operating status of each permanent magnet synchronous motor in real time, allowing the motors to better adapt to different working conditions and improving the stability and robustness of the device.

[0103] Voltage synthesis module 440 is used to synthesize voltages based on the first d-axis current command value i′. d1 First q-axis current command value i′ q1 and preset given value x * Perform current-to-voltage conversion to obtain the first d-axis voltage reference value u. d1 First q-axis voltage reference value u q1 ; and for using the second d-axis current command value i′ d2 Second q-axis current command value i′ q2 and preset given value x * Perform current-to-voltage conversion to obtain the second d-axis voltage reference value u. d2 Second q-axis voltage reference value u q2 Furthermore, the first d-axis voltage reference value u d1 First q-axis voltage reference value u q1 Second d-axis voltage reference value u d2 Second q-axis voltage reference value u q2 The merging process is performed to obtain the merged d-axis voltage control value u. d and q-axis voltage control value u q .

[0104] It should be understood that the voltage reference value u of the first d-axis is... d1 First q-axis voltage reference value u q1The first voltage vector corresponding to the first permanent magnet synchronous motor can be determined. The angle between the first voltage vector and the positive direction of the d-axis is the angle of the first voltage vector, also known as the first voltage angle. The second d-axis voltage reference value u... d2 Second q-axis voltage reference value u q2 The second voltage vector corresponding to the second permanent magnet synchronous motor can be determined. The angle between the second voltage vector and the positive direction of the d-axis is the angle of the second voltage vector, also known as the second voltage angle.

[0105] First d-axis voltage reference value u d1 First q-axis voltage reference value u q1 These are the components of the first voltage vector along the d-axis and q-axis. The second d-axis voltage reference value is u. d2 Second q-axis voltage reference value u q2 These are the components of the second voltage vector on the d-axis and q-axis.

[0106] The d-axis voltage control value u after merging processing d and q-axis voltage control value u q The resultant voltage vector can be determined, and the angle between the resultant voltage vector and the positive d-axis is the angle of the resultant voltage vector. The d-axis voltage control value u... d and q-axis voltage control value u q These are the components of the synthesized voltage vector on the d-axis and q-axis.

[0107] The first voltage angle corresponding to the first permanent magnet synchronous motor is increased and tends to the angle of the composite voltage vector; the first voltage angle corresponding to the second permanent magnet synchronous motor is decreased and tends to the angle of the composite voltage vector. Therefore, the angle deviation between the second voltage angle and the first voltage angle is also reduced, improving the loss of synchronization phenomenon caused by excessive angle deviation due to changes in the load torque of the permanent magnet synchronous motor.

[0108] This application provides a d-axis voltage control value u after merging processing. d and q-axis voltage control value u q Compared to related technologies that use the method of synthesizing the currents of multiple motors, this method of controlling the inverter is closer to the inverter itself and has a faster response speed.

[0109] Wherein, the preset given value x * It can be a preset frequency value f * It can also be a preset rotational speed value n * It should be understood that the preset frequency value f * With the preset speed value n * There is a conversion relationship between them; therefore, a preset given value can be used to preset the frequency value f. * It can also be a preset rotational speed value n * The conversion relationship can be n* =60f * / p n p n p is the number of pole pairs of a permanent magnet synchronous motor. n = p / 2, where p is the extremum.

[0110] It should be understood that angle calculation is involved in the subsequent angle adjustment module 450, and there is a corresponding relationship between the angle calculation and the rating. Therefore, for ease of calculation, the preset given value x is used. * Set to the preset frequency value f * This can improve computational efficiency.

[0111] Among them, the first d-axis voltage reference value u d1 First q-axis voltage reference value u q1 Second d-axis voltage reference value u d2 Second q-axis voltage reference value u q2 The merging process is performed to obtain the magnitude u of the total voltage vector after merging. m and the angle θ of the synthesized voltage vector m Furthermore, based on the modulus u of the synthesized voltage vector m and the angle θ of the synthesized voltage vector m Determine the d-axis voltage control value u d and q-axis voltage control value u q d-axis voltage control value u d and q-axis voltage control value u q After conversion by the second coordinate transformation module 460, the output can be directly sent to the inverter 470 for control, thereby improving the response speed of the motor control device.

[0112] The second coordinate transformation module 460 is used to transform the d-axis voltage control value u in the two-phase rotating coordinate system. d and q-axis voltage control value u q Converted to three-phase control voltage U u U v U w ,Right now Figure 3 U in uvw .

[0113] Furthermore, U uvw The space vector control outputs the PWM control signal required for inverter control. Figure 4 This paper illustrates a schematic diagram of the structure of a motor control device provided in an embodiment of this application for controlling multiple permanent magnet synchronous motors, as shown below. Figure 4 As shown, the three-phase control voltage U uvwThe inverter's switching signals are generated by the Space Vector Pulse Width Modulation (SVPWM) algorithm provided by the space vector control, which controls the on / off state of the power switching devices in the inverter 470, and synthesizes the desired voltage space vector, thereby achieving efficient and precise control of the first permanent magnet synchronous motor and the second permanent magnet synchronous motor.

[0114] The angle adjustment module 450 is used to adjust the actual value i of the first d-axis current. d1 The actual value of the first q-axis current i q1 The actual value of the second d-axis current i d2 The actual value of the second q-axis current i q2 d-axis voltage control value u d q-axis voltage control value u q and preset given value x * The process is performed to obtain the composite angle θ.

[0115] With a preset given value x * The preset frequency value f * For example, specifically, the actual value i of the first d-axis current is obtained through the first phase-locked loop. d1 The actual value of the first q-axis current i q1 d-axis voltage control value u d q-axis voltage control value u q and preset frequency value f * The input is processed to obtain the first observation frequency f1; the actual value of the second d-axis current i is obtained through the second phase-locked loop. d2 The actual value of the second q-axis current i q2 d-axis voltage control value u d q-axis voltage control value u q and preset frequency value f * The process is performed to obtain the second observation frequency f2; then the first observation frequency f1 and the second observation frequency f2 are subjected to frequency-angle conversion and angle synthesis to obtain the synthesized angle θ.

[0116] It should be understood that if a given value x is preset... * The preset rotational speed value n * At that time, the above process still holds true.

[0117] It should be understood that the synthesized angle θ, as a shared rotor position, is used to indicate the coordinate transformation of the first coordinate transformation module 410 and the second coordinate transformation module 460. The synthesized angle θ can take into account the speed changes of the first and second permanent magnet synchronous motors caused by load variations, and thus affect the current command value (the first d-axis current command value i′). d1 First q-axis current command value i′ q1The second d-axis current command value i′ d2 Second q-axis current command value i′ q2 ), voltage control value (i.e., d-axis voltage control value u) d and q-axis voltage control value u q Adjustments will be made.

[0118] When the load torque of the permanent magnet synchronous motor (either the first or the second permanent magnet synchronous motor) changes, the corresponding d-axis voltage reference value of the motor will change, causing the combined voltage vector of the d-axis voltage reference value and the q-axis voltage reference value to shift towards the d-axis voltage control value u. d and q-axis voltage control value u q The corresponding composite voltage vector u m By bringing them closer together, the angle deviation is reduced, that is, the angle between the combined voltage vector of the first permanent magnet synchronous motor and the combined voltage vector of the second permanent magnet synchronous motor is reduced, thereby improving the step loss phenomenon caused by excessive angle deviation of multiple permanent magnet synchronous motors.

[0119] Therefore, the motor control device provided in this application embodiment is used to control a first permanent magnet synchronous motor and a second permanent magnet synchronous motor. The motor control device includes a first coordinate transformation module, a first current regulation module, a second current regulation module, a voltage synthesis module, an angle adjustment module, a second coordinate transformation module, and an inverter. The inverter is electrically connected to the first and second permanent magnet synchronous motors. In the motor control device, the first and second current regulation modules respectively regulate the dq-axis currents of the first and second permanent magnet synchronous motors. The voltage synthesis module synthesizes the converted voltages. Then, the angle adjustment module adjusts the synthesized angle so that the synthesized voltage control values ​​(i.e., the d-axis voltage control value and the q-axis voltage control value) can be transformed by the second coordinate transformation module after the synthesized angle conversion. The transformed second coordinate transformation module performs coordinate transformation to realize the inverter's control of the first and second permanent magnet synchronous motors. The voltage vector corresponding to the synthesized voltage control value is adjusted to reduce angle deviation and improve the loss of synchronization caused by excessive angle deviation of multiple permanent magnet synchronous motors.

[0120] It should be understood that in a three-phase current machine, the three-phase voltage and current are sinusoidal quantities that change with time, and there is a 120° phase difference between them. Analyzing and calculating these three-phase variables is complex. Therefore, the coordinate transformation of the three-phase current output by the first permanent magnet synchronous motor and the three-phase current output by the second permanent magnet synchronous motor are achieved through separate independent coordinate transformation units, namely, the first coordinate transformation unit and the second coordinate transformation unit. In some embodiments, Figure 5 A schematic diagram of another motor control device provided in an embodiment of this application is shown, such as... Figure 5 As shown, the first coordinate transformation module 410 includes a first coordinate transformation unit 411 and a second coordinate transformation unit 412.

[0121] The first coordinate transformation unit 411 is used to transform the three-phase current i output by the first permanent magnet synchronous motor 21 into a coordinate transformation unit. u1 i v1 i w1 Converted to d-axis current in a rotating coordinate system, i.e., the actual value i of the first d-axis current. d1 and the q-axis current, i.e., the actual value of the first q-axis current i q1 .

[0122] The first coordinate transformation unit 411 includes Clark transformation and Park transformation. First, the three-phase current i is transformed using Clark transformation. u1 i v1 i w1 Convert i to αβ coordinate system α1 i β1 Then, through the Park transformation, i α1 i β1 Convert i to dq coordinate system d1 i q1 .

[0123] The second coordinate transformation unit 412 is used to transform the three-phase current i output by the second permanent magnet synchronous motor 22 into a coordinate transformation unit. u2 i v2 i w2 Converted to the d-axis current in a rotating coordinate system, i.e., the actual value i of the second d-axis current. d2 and the q-axis current, i.e., the actual value of the second q-axis current i q2 .

[0124] The second coordinate transformation unit 412 includes Clark transformation and Park transformation. First, the three-phase current i is transformed using Clark transformation. u2 i v2 i w2 Convert i to αβ coordinate system α2 i β2 Then, through the Park transformation, iα2 i β2 Convert i to dq coordinate system d2 i q2 .

[0125] It should be understood that the motor control device performs a series of operations based on the three-phase currents of the first permanent magnet synchronous motor and the second permanent magnet synchronous motor as input data. The implementation process of this series of operations can be referred to the above. Figure 3 Therefore, the motor control device also needs a module to determine the three-phase currents of the first permanent magnet synchronous motor and the second permanent magnet synchronous motor. Figure 6 This invention illustrates a schematic diagram of the structure for determining the three-phase current of a permanent magnet synchronous motor in a motor control device provided in an embodiment of this application. Figure 6 As shown, the motor control device 400 also includes a three-phase current reconstruction module 480, which is used to determine the three-phase current i of the first permanent magnet synchronous motor. u1 i v1 i w1 The three-phase current i of the second permanent magnet synchronous motor u2 i v2 i w2 .

[0126] The input data for the three-phase current reconfiguration module 480 includes the total current i bc The second permanent magnet synchronous motor i u2 and i w2 Among them, the total current i bc The i-value of the second permanent magnet synchronous motor is obtained by setting a sampling resistor on the DC bus. u2 and i w2 This can be obtained by setting a current sensor.

[0127] It should be understood that three-phase current reconstruction is a process in the field of motor control that uses specific algorithms and hardware circuits to calculate the three-phase current based on the detected partial current.

[0128] The three-phase current reconfiguration module 480 needs to reconfigure the total current i bc The second permanent magnet synchronous motor i u2 and i w2 Perform current reconstruction processing; whereby, the total current i bc Perform three-phase current reconstruction to obtain the total three-phase current i u i v i w ; for the second permanent magnet synchronous motor i u2 and i w2 By performing reconstruction based on two-phase current detection, i can be determined. v2 =-(iu2 +i w2 Therefore, the three-phase current i of the second permanent magnet synchronous motor is obtained. u2 i v2 i w2 Three-phase total current i u i v i w Subtract the three-phase current i of the second permanent magnet synchronous motor respectively u2 i v2 i w2 The three-phase current i of the first permanent magnet synchronous motor is obtained. u1 i v1 i w1 .

[0129] It should be understood that permanent magnet synchronous motors used in air conditioners are typically star-connected. For star-connected three-phase windings, I... v +I u +I w =0. Therefore, for the second permanent magnet synchronous motor, at i u2 and i w2 Given that, we can proceed based on i v2 +i u2 +i w2 =0, determine i v2 =-(i u2 +i w2 ).

[0130] Figure 7 A schematic diagram of the three-phase current reconfiguration module in the motor control device provided in this application embodiment is shown, as follows: Figure 7 As shown, the three-phase current reconstruction module 480 includes a first current reconstruction unit 481, a second current reconstruction unit 482, and a two-phase to three-phase current conversion unit 483. The first current reconstruction unit 481 is used to reconstruct the total current i... bc Perform three-phase current reconstruction to obtain the total three-phase current i u i v i w The two-phase to three-phase current conversion unit 483 is used for the i-phase conversion of the second permanent magnet synchronous motor. u2 and i w2 By performing reconstruction based on two-phase current detection, i can be determined. v2 =-(i u2 +i w2 Therefore, the three-phase current i of the second permanent magnet synchronous motor is obtained. u2 i v2 i w2 The second current reconstruction unit 482 is used to convert the three-phase total current i u i v iw Subtract the three-phase current i of the second permanent magnet synchronous motor respectively u2 i v2 i w2 The three-phase current i of the first permanent magnet synchronous motor is obtained. u1 i v1 i w1 .

[0131] In some embodiments, the input data for the three-phase current reconfiguration module may include the total current i bc The first permanent magnet synchronous motor i u1 and i w1 Or it may include the i of the first permanent magnet synchronous motor. u1 and i w1 The second permanent magnet synchronous motor i u2 and i w2 .

[0132] It should be understood that for two-phase current acquisition in a permanent magnet synchronous motor, it can be any two phases, or it can be I... v I u It can also be I u I w It can also be I v I w .

[0133] This application embodiment uses a smaller number of current sensors and sampling resistors to determine the three-phase current of the first permanent magnet synchronous motor and the second permanent magnet synchronous motor, thereby reducing the structural complexity of the motor control device and accurately acquiring the three-phase current, providing a basis for subsequent motor control and other operations.

[0134] It should also be understood that, in some embodiments, the three-phase current i of the first permanent magnet synchronous motor can be directly measured by setting six current sensors. u1 i v1 i w1 The three-phase current i of the second permanent magnet synchronous motor u2 i v2 i w2 During data acquisition, the motor control device does not need to be equipped with a three-phase current reconstruction module.

[0135] In this embodiment of the application, the first current regulation module 420 and the second current regulation module 430 are used to control the current during the startup process. The corresponding preset value for i d1 i q1 i d2 i q2 Adjustments can enable the corresponding permanent magnet synchronous motor to quickly establish a suitable magnetic field and torque, reducing start-up time and improving the dynamic performance of the device. Therefore, such as Figure 5 As shown, the first current regulation module 420 includes a first limiting unit 421 and a first selection unit 422; the second current regulation module 430 includes a second limiting unit 431 and a second selection unit 432.

[0136] The first limiting unit 421 is used to limit the actual value i of the first d-axis current. d1 With the first d-axis current given value A limiting process is performed to indicate the first d-axis current command value i′. d1 Set the first d-axis current value The corresponding preset value is either zero or N1. N1 is a value determined based on the parameters and operating conditions of the first permanent magnet synchronous motor, and this value is a small value that tends towards zero.

[0137] It should be understood that if the first permanent magnet synchronous motor is a surface-mounted permanent magnet synchronous motor, the preset value is zero, i.e. but If the first permanent magnet synchronous motor is an embedded permanent magnet synchronous motor, the preset value is N1, that is... but

[0138] The first selection unit 422 is used to input the actual value of the first q-axis current i. q1 With the first q-axis current given value After selection processing, the first q-axis current command value i′ is obtained. q1 During the startup process, After startup, i′ q1 =i q1 It should be understood that the first q-axis current setpoint This is also a preset value. This preset value is determined based on the performance and application requirements of the first permanent magnet synchronous motor.

[0139] The second limiting unit 431 is used to limit the actual value i of the second d-axis current. d2 With the second d-axis current given value A limiting process is performed to indicate the second d-axis current command value i′. d2 Set the value for the second d-axis current The corresponding preset value is either zero or N2. N2 is a value determined based on the parameters and operating conditions of the second permanent magnet synchronous motor, and this value is a small value that tends towards zero.

[0140] It should be understood that if the second permanent magnet synchronous motor is a surface-mounted permanent magnet synchronous motor, the preset value is zero, i.e. but If the second permanent magnet synchronous motor is an embedded permanent magnet synchronous motor, the preset value is N2, that is... but

[0141] The second selection unit 432 is used to input the actual value of the second q-axis current i. q2 With the second q-axis current given value After selection processing, the second q-axis current command value i′ is obtained. q2 During the startup process, After startup, i′ q2 =i q2 It should be understood that the given value of the second q-axis current... This is also a preset value. This preset value is determined based on the performance and application requirements of the second permanent magnet synchronous motor.

[0142] The first current regulation module 420 and the second current regulation module 430 differ from the current loop in related technologies for current control. Furthermore, after startup, current feedback is introduced to monitor the actual operating status of each permanent magnet synchronous motor in real time, enabling the permanent magnet synchronous motors to better adapt to different working conditions and improving the stability and robustness of the device.

[0143] To achieve control of the combined voltage of the first and second permanent magnet synchronous motors and to enable rapid response of the inverter control, such as... Figure 5 As shown, the voltage synthesis module 440 includes a first voltage model unit 441, a second voltage model unit 442, and a voltage synthesis unit 443.

[0144] The first voltage model unit 441 is used to calculate the first d-axis current command value i′. d1 First q-axis current command value i′ q1 and preset frequency value f * Perform current-to-voltage conversion to obtain the first d-axis voltage reference value u. d1 First q-axis voltage reference value u q1 The second voltage model unit 442 is used to determine the second d-axis current command value i′. d2 Second q-axis current command value i′ q2 and preset frequency value f * Perform current-to-voltage conversion to obtain the second d-axis voltage reference value u. d2 Second q-axis voltage reference value u q2 The voltage synthesis unit 443 is used to synthesize the first d-axis voltage reference value u. d1 First q-axis voltage reference value u q1 Second d-axis voltage reference value u d2 Second q-axis voltage reference value u q2 The merging process is performed to obtain the merged d-axis voltage control value u. d and q-axis voltage control value uq .

[0145] For the first voltage model unit 441 and the second voltage model unit 442, the corresponding voltage values ​​are determined by the following voltage calculation formula (first d-axis voltage reference value u). d1 and the first q-axis voltage reference value u q1 Second d-axis voltage reference value u d2 Second q-axis voltage reference value u q2 ):

[0146]

[0147] Where r is the stator resistance, Ld and Lq are the dq-axis inductances of the permanent magnet synchronous motor, Ke is the permanent magnet flux linkage of the permanent magnet synchronous motor, and ω is the electric angular velocity.

[0148] Therefore, the d-axis components of the first and second permanent magnet synchronous motors during operation can be determined, namely the first d-axis voltage reference value u. d1 Second d-axis voltage reference value u d2 The formula is as follows:

[0149]

[0150] In the following Figure 13 , Figure 14 In the example, the first d-axis voltage reference value u can be obtained using Formula 1. d1 Second d-axis voltage reference value u d2 We will analyze the changes.

[0151] In some embodiments, for ease of understanding, since i′ d1 and i′ d2 For values ​​that are zero or close to zero, Formula 1 can be adjusted. The adjusted formula is as follows:

[0152]

[0153] In the following Figure 13 , Figure 14 In the example, the first d-axis voltage reference value u can also be obtained using Formula 1. d1 Second d-axis voltage reference value u d2 We will analyze the changes.

[0154] It should be understood that, Figure 5 In the example shown, a preset given value x * The preset frequency value f * This improves output processing speed.

[0155] This application provides a d-axis voltage control value u after merging processing.d and q-axis voltage control value u q Compared to related technologies that use the method of synthesizing the currents of multiple motors, this method of controlling the inverter is closer to the inverter itself and has a faster response speed.

[0156] It should be noted that the voltage synthesis unit 443 uses the first d-axis voltage reference value u d1 First q-axis voltage reference value u q1 Second d-axis voltage reference value u d2 Second q-axis voltage reference value u q2 The merging process is performed to obtain the magnitude u of the total voltage vector after merging. m and the angle θ of the synthesized voltage vector m Furthermore, based on the modulus u of the synthesized voltage vector m and the angle θ of the synthesized voltage vector m Determine the d-axis voltage control value u d and q-axis voltage control value u q . Figure 8 A schematic diagram of the voltage synthesis unit in the motor control device provided in this application embodiment is shown, as follows: Figure 8 As shown, the voltage synthesis unit 443 includes a mode synthesis subunit 443A, a first angle subunit 443B, a second angle subunit 443C, an angle synthesis subunit 443D, and a voltage synthesis subunit 443F.

[0157] Among them, the modeling subunit 443A is used for the first d-axis voltage reference value u d1 First q-axis voltage reference value u q1 Second d-axis voltage reference value u d2 Second q-axis voltage reference value u q2 The process is performed to obtain the magnitude u of the synthesized voltage vector. m .

[0158] The first angle subunit 443B is used to determine the first d-axis voltage reference value u. d1 First q-axis voltage reference value u q1 Determine the first voltage angle θ u1 .

[0159] The second angle subunit 443C is used to determine the second d-axis voltage reference value u. d2 Second q-axis voltage reference value u q2 Determine the second voltage angle θ u2 .

[0160] Angle synthesis subunit 443D is used for angle synthesis based on a first voltage angle θ u1 Second voltage angle θ u2 Determine the angle θ of the synthesized voltage vector.m .

[0161] The voltage synthesis subunit 443F is used for modular u based on the synthesized voltage vector. m and the angle θ of the synthesized voltage vector m Determine the d-axis voltage control value u d and q-axis voltage control value u q .

[0162] Figure 9 This diagram illustrates the voltage synthesis in the motor control device provided in this embodiment, showing the voltage reference value u of the first d-axis. d1 First q-axis voltage reference value u q1 Second d-axis voltage reference value u d2 Second q-axis voltage reference value u q2 In the synthesis process, the first d-axis voltage reference value u d1 That is, the component on the d-axis; the first q-axis voltage reference value u q1 That is, the components on the q-axis, the magnitude u1 of the first voltage vector synthesized from these two components, and the first voltage angle θ. u1 ,like Figure 9 As shown; the second d-axis voltage reference value u d2 That is, the component on the d-axis; the second q-axis voltage reference value u q2 That is, the component on the q-axis, the magnitude u2 of the second voltage vector synthesized from these two components, and the second voltage angle θ. u1 ,like Figure 9 As shown.

[0163] The modulus u1 of the first voltage vector and the modulus u2 of the second voltage vector are combined to obtain the modulus u of the combined voltage vector. m and the angle θ of the synthesized voltage vector m The magnitude of the synthesized voltage vector u m The component on the d-axis is the d-axis voltage control value u. d The component on the q-axis is the q-axis voltage control value u. q .

[0164] This application provides a d-axis voltage control value u after merging processing. d and q-axis voltage control value u q Controlling the inverter is done closer to the inverter, resulting in a faster response time.

[0165] The angle adjustment module involves angle calculation, and the angle calculation is related to the frequency. Therefore, to facilitate the calculation, a preset value x is used. * Set to the preset frequency value f * This can improve computational efficiency. The angle adjustment module is used to adjust the actual value i of the first d-axis current.d1 The actual value of the first q-axis current i q1 The actual value of the second d-axis current i d2 The actual value of the second q-axis current i q2 d-axis voltage control value u d q-axis voltage control value u q and preset given value x * The process is performed to obtain the composite angle θ. Figure 10 This paper shows a schematic diagram of the structure of an angle adjustment module in a motor control device provided in an embodiment of this application. Figure 10 As shown, the angle adjustment module 450 includes a first phase-locked loop 451, a second phase-locked loop 452, a speed synthesis unit 453, and an angle calculation unit 454.

[0166] The first phase-locked loop 451 is used to determine the actual value of the first d-axis current i. d1 The actual value of the first q-axis current i q1 d-axis voltage control value u d q-axis voltage control value u q and preset frequency value f * Determine the first observation frequency f1.

[0167] The second phase-locked loop 452 is used to determine the actual value of the second d-axis current i. d2 The actual value of the second q-axis current i q2 d-axis voltage control value u d q-axis voltage control value u q and preset frequency value f * Determine the second observation frequency f2.

[0168] The rotational speed synthesis unit 453 is used to synthesize the first observation frequency f1 and the second observation frequency f2 to obtain the synthesized observation frequency f. r Synthetic observation frequency f r The calculation process is as follows:

[0169]

[0170] Angle calculation unit 454 is used to input the synthetic observation frequency f r A frequency-to-angle conversion is performed to obtain the composite angle θ. The calculation process for the composite angle θ is as follows:

[0171] θ=f r ×t

[0172] Where t is time, typically the period of the PWM.

[0173] It should be understood that both the first phase-locked loop 451 and the second phase-locked loop 452 are sensorless phase-locked loops. In the vector control of permanent magnet synchronous motors, it is necessary to accurately know the rotor's position and speed in order to achieve precise control of the motor. Sensorless phase-locked loops can estimate the rotor's position and speed by observing signals such as the motor's back electromotive force, thereby replacing traditional position sensors, reducing system costs, and improving system reliability and adaptability.

[0174] In some embodiments, the angle adjustment module can also be implemented in other ways. Figure 11 This illustration shows a structural schematic diagram of another angle adjustment module in the motor control device provided in an embodiment of this application, such as... Figure 11 As shown, the angle adjustment module 450 includes a first phase-locked loop 451, a second phase-locked loop 452, a first angle calculation unit 455, a second angle calculation unit 456, and an angle synthesis unit 457.

[0175] The first angle calculation unit 455 is used to perform frequency-angle conversion on the first observation frequency f1 to obtain the first angle θ1.

[0176] The second angle calculation unit 456 is used to perform frequency-angle conversion on the second observation frequency f2 to obtain the second angle θ2.

[0177] The angle synthesis unit 457 is used to synthesize the first angle θ1 and the second angle θ2 to obtain the synthesized angle θ.

[0178] The implementation process of the first phase-locked loop 451, the second phase-locked loop 452, the first angle calculation unit 455, the second angle calculation unit 456, and the angle synthesis unit 457 can be referred to the above. Figure 9 A detailed description.

[0179] It should be understood that the synthesized angle θ, as a shared rotor position, is used to indicate the coordinate transformation between the first coordinate transformation module 410 and the second coordinate transformation module. The synthesized angle θ can accommodate the speed changes of both the first and second permanent magnet synchronous motors caused by load variations, thereby affecting the current command value (the first d-axis current command value i′). d1 First q-axis current command value i′ q1 The second d-axis current command value i′ d2 Second q-axis current command value i′ q2 ), voltage control value (i.e., d-axis voltage control value u) d and q-axis voltage control value u q Adjustments will be made.

[0180] Figure 12 A schematic diagram of another motor control device provided in an embodiment of this application is shown, such as... Figure 12As shown, the first unit 481 of the current reconstruction pairs the total current i bc Perform three-phase current reconstruction to obtain the total three-phase current i u i v i w The two-phase to three-phase current conversion unit 483 is used for the i-phase conversion of the second permanent magnet synchronous motor. u2 and i w2 Reconstruction based on two-phase current detection is performed to obtain the three-phase current i of the second permanent magnet synchronous motor. u2 i v2 i w2 Then the total three-phase current i u i v i w Subtract the three-phase current i of the second permanent magnet synchronous motor respectively u2 i v2 i w2 The three-phase current i of the first permanent magnet synchronous motor is obtained. u1 i v1 i w1 .

[0181] The three-phase current i of the first permanent magnet synchronous motor are respectively u1 i v1 i w1 The three-phase current i of the second permanent magnet synchronous motor u2 i v2 i w2 The actual value of the first d-axis current i is obtained by Clark transformation and Park transformation. d1 and the actual value of the first q-axis current i q1 The actual value of the second d-axis current i d2 The actual value of the second q-axis current i q2 .

[0182] The first limiting unit 421 limits the actual value of the first d-axis current i. d1 With the first d-axis current given value After performing limiting processing, the first d-axis current command value i′ is obtained. d1 The first selection unit 422 inputs the actual value of the first q-axis current i. q1 With the first q-axis current given value After selection processing, the first q-axis current command value i′ is obtained. q1 .

[0183] The second limiting unit 431 restricts the actual value of the second d-axis current i. d2 With the second d-axis current given value After performing limiting processing, the second d-axis current command value i′ is obtained. d2 The second selection unit 432 inputs the actual value of the second q-axis current i.q2 With the second q-axis current given value After selection processing, the second q-axis current command value i′ is obtained. q2 .

[0184] The first voltage model unit 441 commands the first d-axis current value i′ d1 First q-axis current command value i′ q1 and preset frequency value f * Perform current-to-voltage conversion to obtain the first d-axis voltage reference value u. d1 First q-axis voltage reference value u q1 The second voltage model unit 442 commands the second d-axis current value i′. d2 Second q-axis current command value i′ q2 and preset frequency value f * Perform current-to-voltage conversion to obtain the second d-axis voltage reference value u. d2 Second q-axis voltage reference value u q2 The voltage synthesis unit 443 references the first d-axis voltage value u. d1 First q-axis voltage reference value u q1 Second d-axis voltage reference value u d2 Second q-axis voltage reference value u q2 The merging process is performed to obtain the merged d-axis voltage control value u. d and q-axis voltage control value u q .

[0185] The first phase-locked loop 451 is based on the actual value of the first d-axis current i d1 The actual value of the first q-axis current i q1 d-axis voltage control value u d q-axis voltage control value u q and preset frequency value f * The first observation frequency f1 is determined. The second phase-locked loop 452 determines the second d-axis current based on the actual value i. d2 The actual value of the second q-axis current i q2 d-axis voltage control value u d q-axis voltage control value u q and preset frequency value f * The second observation frequency f2 is determined. The rotational speed synthesis unit 453 synthesizes the first observation frequency f1 and the second observation frequency f2 to obtain the synthesized observation frequency f2. r The angle calculation unit 454 is used to calculate the composite observation frequency input f. r A frequency-to-angle transformation is performed to obtain the composite angle θ. This composite angle θ is used to indicate the coordinate transformations of the Park transform and the dq / uvw transform, thereby adjusting the results of the coordinate transformation.

[0186] d-axis voltage control value u d and q-axis voltage control value u q After dq / uvw conversion, the output three-phase control voltage U is obtained. u U v U w , that is U uvw U uvw The inverter outputs the PWM control signal required by the space vector control, and then the PWM control signal controls the inverter to regulate the first permanent magnet synchronous motor and the second permanent magnet synchronous motor.

[0187] This embodiment employs a first voltage model unit and a second voltage model unit for current-to-voltage conversion, along with a voltage synthesis unit that approximates the inverter output to merge the voltages. This eliminates the complexity of dual-loop control, as the voltage synthesis of the two motors is directly output to the inverter for control, resulting in a faster response. Furthermore, the speeds and angles of multiple permanent magnet synchronous motors are synthesized as a shared rotor position for coordinate transformation. The synthesized frequency and angle can accommodate speed changes in multiple permanent magnet synchronous motors caused by load variations, thereby adjusting the current and voltage.

[0188] It should be understood that during the drive and control of multiple permanent magnet synchronous motors using a single inverter, if the load torque exceeds the maximum electromagnetic torque of the synchronous motor, the rotor will lose synchronization, resulting in a loss of synchronism. This will lead to a decrease in motor speed, an increase in current, and may even cause the motor to stop operating. Based on the above... Figures 3-12 The described embodiment provides a motor control device, taking two permanent magnet synchronous motors as an example, which can vector the dq-axis voltages of the two permanent magnet synchronous motors towards u when load changes cause angular deviations in the two permanent magnet synchronous motors. m By moving closer together, the angular deviation is reduced, thus improving the phenomenon of losing synchronization caused by excessive angular deviation.

[0189] Figure 13 This illustration shows a schematic diagram of angle adjustment for an example of increasing the load torque of the first permanent magnet synchronous motor in the motor control device provided in this application embodiment, taking the change in the load torque of the first permanent magnet synchronous motor as an example. When the load torque of the first permanent magnet synchronous motor does not change, such as... Figure 13 As shown in (1), at this time, the angular deviation is Δθ1=θ u2 -θ u1 When the load torque of the first permanent magnet synchronous motor increases, the magnitude u1 of the first voltage vector of the first permanent magnet synchronous motor lags behind the magnitude u of the synthesized voltage vector. m The first observation frequency f1 output by the first phase-locked loop decreases, and the synthesized observation frequency f r As the angle θ decreases, the actual value of the first q-axis current i...q1 Increase the first q-axis current command value i′ q1 As the voltage increases, according to Formula 1 (or Formula 2), the reference value of the first d-axis voltage, u... d1 It will change in the negative direction of the d-axis to obtain the first d-axis voltage adjustment value u′. d1 This causes the magnitude u1 of the first voltage vector to be shifted towards the magnitude u of the synthesized voltage vector. m Approaching, and thus, the first d-axis voltage adjustment value u′ d1 The corresponding angle is θ′ u1 , and θ′ u1 >θ u1 ,like Figure 13 As shown in (2) in the figure; at this time, the angular deviation becomes Δθ1′=θ u2 -θ′ u1 The Δθ1′ < Δθ1 means that the angle deviation is reduced, which improves the phenomenon of loss of synchronization caused by excessive angle deviation.

[0190] It should be understood that during the above-mentioned control and adjustment process of the first permanent magnet synchronous motor, the synthesized angle will affect the coordinate transformation of the first coordinate transformation module and the second coordinate transformation module. In other words, the motor control method proposed in this application embodiment will also adjust the data corresponding to the second permanent magnet synchronous motor, such as... Figure 13 As shown in (3), the modulus u2 of the second voltage vector of the second permanent magnet synchronous motor will also contribute to the modulus u of the synthesized voltage vector. m Approaching, and thus the second d-axis voltage adjustment value u′ d2 The corresponding angle θ′ u2 The angle will become smaller, and the angular deviation between the two voltage angles will become smaller than Δθ1′, which is θ′. u2 -θ′ u1 This improves the problem of step loss caused by excessive angular deviation.

[0191] Figure 14 This illustration shows a schematic diagram of the angle adjustment for reducing the load torque of the second permanent magnet synchronous motor in the motor control device provided in this application embodiment, taking the change in the load torque of the second permanent magnet synchronous motor as an example. When the load torque of the second permanent magnet synchronous motor does not change, such as... Figure 14 As shown in (1), at this time, the angular deviation is Δθ2=θ u2 -θ u1 When the load torque of the second permanent magnet synchronous motor decreases, the magnitude u2 of the second voltage vector of the second permanent magnet synchronous motor leads the magnitude u of the synthesized voltage vector. m The second observation frequency f2 output by the second phase-locked loop increases, and the synthesized observation frequency f r As the angle θ increases, the actual value of the second q-axis current i... q2 Decrease the second q-axis current command value i′ q2As the voltage decreases, according to Formula 1 (or Formula 2), the reference value of the second d-axis voltage, u, is... d2 It will change in the positive direction of the d-axis to obtain the second d-axis voltage adjustment value u″. d2 This causes the magnitude u2 of the second voltage vector to shift towards the magnitude u of the synthesized voltage vector. m Approaching, and thus, the second d-axis voltage adjustment value u″ d2 The corresponding angle is θ″ u2 , and θ″ u2 <θ u2 ,like Figure 14 As shown in (2); the angular deviation at this time becomes Δθ2′=θ″. u2 -θ u1 The Δθ2′<Δθ2 means that the angular deviation is reduced, which improves the phenomenon of loss of synchronization caused by excessive angular deviation.

[0192] It should be understood that during the above-mentioned control and adjustment process of the second permanent magnet synchronous motor, the synthesized angle will affect the coordinate transformation of the first coordinate transformation module and the second coordinate transformation module. In other words, the motor control method proposed in this application embodiment will also adjust the data corresponding to the first permanent magnet synchronous motor, such as... Figure 14 As shown in (3), the modulus u1 of the first voltage vector of the first permanent magnet synchronous motor will also contribute to the modulus u of the synthesized voltage vector. m Approaching, and thus the first d-axis voltage adjustment value u″ d1 The corresponding angle θ″ u1 The angle will increase, and at this point, the angular deviation between the two voltage angles will become smaller than Δθ2′, which is θ″. u2 -θ″ u1 This improves the problem of step loss caused by excessive angular deviation.

[0193] To facilitate a further understanding of the technical solutions in some embodiments of this application, the technical solutions of the motor control method and how these solutions solve the aforementioned technical problems are described in detail below with reference to specific embodiments and accompanying drawings. The embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. Obviously, the described embodiments are only some, not all, of the embodiments of this application.

[0194] Figure 15 This paper illustrates a flowchart of a motor control method provided in an embodiment of this application, which is applied to the above-mentioned... Figure 3 The motor control device shown takes two permanent magnet synchronous motors as an example. Figure 15 As shown, the motor control method includes the following steps:

[0195] S510. Perform coordinate transformation on the three-phase output current of the first permanent magnet synchronous motor and the three-phase output current of the second permanent magnet synchronous motor respectively to obtain the actual values ​​of the first d-axis current, the first q-axis current, the second d-axis current, and the second q-axis current.

[0196] S520. Adjust the actual values ​​of the first d-axis current and the first q-axis current to obtain the command values ​​of the first d-axis current and the first q-axis current, and adjust the actual values ​​of the second d-axis current and the second q-axis current to obtain the command values ​​of the second d-axis current and the second q-axis current.

[0197] Specifically, the actual value of the first d-axis current and the given value of the first d-axis current are restricted to obtain the command value of the first d-axis current. The restriction process is used to indicate that the command value of the first d-axis current is a preset value, and the preset value is a value of zero or a value of 0. The actual value of the first q-axis current and the given value of the first q-axis current are selected to obtain the command value of the first q-axis current.

[0198] The actual value of the second d-axis current and the given value of the second d-axis current are restricted to obtain the command value of the second d-axis current. The restriction process is used to indicate that the command value of the second d-axis current is a preset value, and the preset value is a value of zero or a value of 0. The actual value of the second q-axis current and the given value of the second q-axis current are selected to obtain the command value of the second q-axis current.

[0199] S530: Based on the first d-axis current command value, the first q-axis current command value, the second d-axis current command value, the second q-axis current command value, and the preset given value, the voltage is combined to obtain the d-axis voltage control value and the q-axis voltage control value.

[0200] Specifically, the first d-axis current command value, the first q-axis current command value, and the preset setpoint are converted from current to voltage to obtain the first d-axis voltage reference value and the first q-axis voltage reference value; the second d-axis current command value, the second q-axis current command value, and the preset setpoint are converted from current to voltage to obtain the second d-axis voltage reference value and the second q-axis voltage reference value; the first d-axis voltage reference value, the first q-axis voltage reference value, the second d-axis voltage reference value, and the second q-axis voltage reference value are combined to obtain the d-axis voltage control value and the q-axis voltage control value.

[0201] In some embodiments, the voltage synthesis unit 443 adjusts the first d-axis voltage reference value u. d1 First q-axis voltage reference value u q1 Second d-axis voltage reference value u d2 Second q-axis voltage reference value u q2 The merging process is performed to obtain the merged d-axis voltage control value u. d and q-axis voltage control value uq Perform the following steps (1)-(5):

[0202] (1) Perform a first processing on the first d-axis voltage reference value, the first q-axis voltage reference value, the second d-axis voltage reference value, and the second q-axis voltage reference value to obtain the magnitude of the composite voltage vector. The calculation process of the magnitude of the composite voltage vector is as follows:

[0203]

[0204] Among them, u d1 The first d-axis voltage reference value, u q1 The first q-axis voltage reference value, u d2 The second d-axis voltage reference value, u q2 The second q-axis voltage reference value, u m This represents the magnitude of the synthesized voltage vector.

[0205] (2) Based on the first d-axis voltage reference value and the first q-axis voltage reference value, the first voltage angle is determined. The calculation process of the first voltage angle is as follows:

[0206]

[0207] Where, θ u1 This is the first voltage angle.

[0208] (3) Based on the second d-axis voltage reference value and the second q-axis voltage reference value, determine the second voltage angle. The calculation process of the second voltage angle is as follows:

[0209]

[0210] Where, θ u2 This is the second voltage angle.

[0211] (4) Based on the first voltage angle and the second voltage angle, determine the angle of the composite voltage vector. The calculation process of the angle of the composite voltage vector is as follows:

[0212]

[0213] Where, θ m The angle of the synthesized voltage vector.

[0214] (5) Based on the magnitude and angle of the synthesized voltage vector, determine the d-axis voltage control value and the q-axis voltage control value. The calculation process for the d-axis voltage control value and the q-axis voltage control value is as follows:

[0215]

[0216] Among them, u d This is the d-axis voltage control value, uq This is the q-axis voltage control value.

[0217] S540. Based on the actual values ​​of the first d-axis current, the first q-axis current, the second d-axis current, the second q-axis current, the d-axis voltage control value, the q-axis voltage control value, and the preset given value, determine the composite angle.

[0218] The composite angle is used to indicate the coordinate transformation during the coordinate system transformation process.

[0219] Specifically, a first observation frequency is determined based on the actual values ​​of the first d-axis current, the first q-axis current, the d-axis voltage control value, the q-axis voltage control value, and a preset given value; a second observation frequency is determined based on the actual values ​​of the second d-axis current, the second q-axis current, the d-axis voltage control value, the q-axis voltage control value, and a preset given value; the first and second observation frequencies are converted and synthesized to obtain a composite angle.

[0220] S550 performs coordinate transformation on the d-axis voltage control value and the q-axis voltage control value. The resulting signals are processed by the inverter to obtain the target AC signal.

[0221] The target AC signal is used to control the first permanent magnet synchronous motor and the second permanent magnet synchronous motor.

[0222] For the implementation process of steps 510 to 550, please refer to the above. Figures 3-12 A detailed description of it is omitted here.

[0223] This application embodiment performs current-to-voltage conversion and voltage merging on the currents of the first and second permanent magnet synchronous motors, eliminating the complexity of dual closed-loop control. Since the voltages of the two motors are directly synthesized and output to the inverter for control, the response is faster. Furthermore, the speeds and angles of multiple permanent magnet synchronous motors are synthesized as a shared rotor position for coordinate transformation. The synthesized frequency and angle can accommodate speed changes in multiple permanent magnet synchronous motors caused by load variations, thereby adjusting the current and voltage.

[0224] This application also provides an air conditioner, including an indoor unit, an outdoor unit, and a motor control device. The outdoor unit includes M fans. The motor control device is used to control the M fans via M permanent magnet synchronous motors, where M is a positive integer greater than 1.

[0225] It should be understood that the motor control device is used to execute the above-mentioned motor control methods.

[0226] It should be understood that the air conditioner provided in this application embodiment can have various implementation forms, such as central air conditioning, multi-split air conditioning, etc. Central air conditioning is a system in which one or more outdoor units deliver cooling or heating to multiple indoor areas through systems such as air ducts or hot and cold water pipes, thereby achieving centralized air conditioning of the entire building or a large space. Multi-split air conditioning is a special form of central air conditioning.

[0227] Specific details, such as particular system architectures and techniques, are set forth for illustrative purposes and not for limitation, to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application can be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods are omitted to avoid unnecessary detail that could obscure the description of this application.

[0228] It should be understood that in the various embodiments of this application, the order of the above-mentioned processes does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0229] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0230] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0231] In the several embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for example, the division of units is merely a logical functional division, and there may be other division methods in actual implementation; for example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces, and the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0232] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0233] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0234] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A motor control method, characterized in that, The invention is applied to a motor control device, which includes a first coordinate transformation module, a voltage synthesis module, an angle adjustment module, a second coordinate transformation module, and an inverter. The inverter is electrically connected to a first permanent magnet synchronous motor and a second permanent magnet synchronous motor. When the load torque of the first permanent magnet synchronous motor and / or the second permanent magnet synchronous motor changes, the motor control method includes: The three-phase current output by the first permanent magnet synchronous motor and the three-phase current output by the second permanent magnet synchronous motor are input to the first coordinate transformation module to obtain the actual values ​​of the first d-axis current, the first q-axis current, the second d-axis current, and the second q-axis current. The first d-axis current command value, the first q-axis current command value, the second d-axis current command value, the second q-axis current command value, and a preset given value are input to the voltage synthesis module to obtain the voltage-combined d-axis voltage control value and q-axis voltage control value. The first d-axis current command value and the first q-axis current command value are determined by the actual value of the first d-axis current and the actual value of the first q-axis current. The second d-axis current command value and the second q-axis current command value are determined by the actual value of the second d-axis current and the actual value of the second q-axis current. The first voltage angle corresponding to the first permanent magnet synchronous motor is increased and tends to the angle of the composite voltage vector, and the first voltage angle corresponding to the second permanent magnet synchronous motor is decreased and tends to the angle of the composite voltage vector, wherein the composite voltage is determined by the d-axis voltage control value and the q-axis voltage control value; The actual values ​​of the first d-axis current, the first q-axis current, the second d-axis current, the second q-axis current, the d-axis voltage control value, the q-axis voltage control value, and the preset given value are input to the angle adjustment module to obtain a composite angle. The composite angle is used to indicate the coordinate transformation between the first coordinate transformation module and the second coordinate transformation module. The d-axis voltage control value and the q-axis voltage control value are input to the second coordinate transformation module. The signal output by the second coordinate transformation module is processed by the inverter to obtain the target AC signal after angle adjustment. The target AC signal is used to control the first permanent magnet synchronous motor and the second permanent magnet synchronous motor.

2. The motor control method according to claim 1, characterized in that, The motor control device further includes a first current regulation module and a second current regulation module. After the three-phase currents output by the first permanent magnet synchronous motor and the second permanent magnet synchronous motor are input to the first coordinate transformation module to obtain the actual values ​​of the first d-axis current, the first q-axis current, the second d-axis current, and the second q-axis current, and before the first d-axis current command value, the first q-axis current command value, the second d-axis current command value, the second q-axis current command value, and a preset given value are input to the voltage synthesis module to obtain the voltage-combined d-axis voltage control value and the q-axis voltage control value, the device further includes: The first d-axis current actual value and the first q-axis current actual value are input to the first current control module to obtain the first d-axis current command value and the first q-axis current command value. The actual values ​​of the second d-axis current and the second q-axis current are input to the second current control module to obtain the second d-axis current command value and the second q-axis current command value.

3. The motor control method according to claim 1, characterized in that, The first d-axis current actual value and the first q-axis current actual value are input to the first current control module to obtain the first d-axis current command value and the first q-axis current command value. The actual values ​​of the second d-axis current and the second q-axis current are input to the second current control module to obtain the second d-axis current command value and the second q-axis current command value, including: The actual value of the first d-axis current and the given value of the first d-axis current are restricted to obtain the command value of the first d-axis current. The restriction processing is used to indicate that the command value of the first d-axis current is a preset value. The preset value is zero or N1, where N1 is a value determined according to the parameters and operating conditions of the first permanent magnet synchronous motor. The actual value of the first q-axis current and the given value of the first q-axis current are selected to obtain the command value of the first q-axis current; and / or The actual value of the second d-axis current and the given value of the second d-axis current are restricted to obtain the command value of the second d-axis current. The restriction process is used to indicate that the command value of the second d-axis current is a preset value. The preset value is zero or N2, where N2 is a value determined according to the parameters and operating conditions of the second permanent magnet synchronous motor. The actual value of the second q-axis current and the given value of the second q-axis current are selected to obtain the command value of the second q-axis current.

4. The motor control method according to any one of claims 1 to 3, characterized in that, The step of inputting the first d-axis current command value, the first q-axis current command value, the second d-axis current command value, the second q-axis current command value, and a preset given value into the voltage synthesis module to obtain the combined d-axis voltage control value and q-axis voltage control value includes: The first d-axis current command value, the first q-axis current command value, and the preset given value are input to the voltage synthesis module to obtain the first d-axis voltage reference value and the first q-axis voltage reference value; The second d-axis current command value, the second q-axis current command value, and the preset given value are input to the voltage synthesis module to obtain the second d-axis voltage reference value and the second q-axis voltage reference value; The voltage synthesis module merges the first d-axis voltage reference value, the first q-axis voltage reference value, the second d-axis voltage reference value, and the second q-axis voltage reference value to obtain the d-axis voltage control value and the q-axis voltage control value.

5. The motor control method according to any one of claims 1 to 3, characterized in that, The step of inputting the first d-axis current command value, the first q-axis current command value, the second d-axis current command value, the second q-axis current command value, and a preset given value into the voltage synthesis module to obtain the combined d-axis voltage control value and q-axis voltage control value includes: The first d-axis current command value, the first q-axis current command value, and the preset given value are input to the voltage synthesis module to obtain the first d-axis voltage reference value and the first q-axis voltage reference value; The second d-axis current command value, the second q-axis current command value, and the preset given value are input to the voltage synthesis module to obtain the second d-axis voltage reference value and the second q-axis voltage reference value; The first d-axis voltage reference value, the first q-axis voltage reference value, the second d-axis voltage reference value, and the second q-axis voltage reference value are processed to obtain the magnitude of the synthesized voltage vector; The first voltage angle and the second voltage angle are combined and calculated to obtain the angle of the combined voltage vector. The first voltage angle is determined by the first d-axis voltage reference value and the first q-axis voltage reference value, and the second voltage angle is determined by the second d-axis voltage reference value and the second q-axis voltage reference value. The d-axis voltage control value and the q-axis voltage control value are determined based on the magnitude and angle of the synthesized voltage vector.

6. The motor control method according to claim 4, characterized in that, The voltage synthesis module performs a merging process on the first d-axis voltage reference value, the first q-axis voltage reference value, the second d-axis voltage reference value, and the second q-axis voltage reference value, including: The first d-axis voltage reference value, the first q-axis voltage reference value, the second d-axis voltage reference value, and the second q-axis voltage reference value are subjected to a first processing step to obtain the magnitude of the composite voltage vector. The calculation process of the magnitude of the composite voltage vector is as follows: Among them, u d1 The first d-axis voltage reference value, u q1 The first q-axis voltage reference value, u d2 The second d-axis voltage reference value, u q2 The second q-axis voltage reference value, u m The magnitude of the synthesized voltage vector; Based on the calculation and processing of the first d-axis voltage reference value and the first q-axis voltage reference value, the first voltage angle is obtained. The calculation process of the first voltage angle is as follows: Where, θ u1 The first voltage angle; Based on the calculation and processing of the second d-axis voltage reference value and the second q-axis voltage reference value, the second voltage angle is obtained. The calculation process of the second voltage angle is as follows: Where, θ u2 This refers to the second voltage angle; The first voltage angle and the second voltage angle are combined to obtain the angle of the combined voltage vector. The calculation process of the angle of the combined voltage vector is as follows: Where, θ m The angle of the synthesized voltage vector; Based on the magnitude and angle of the synthesized voltage vector, the d-axis voltage control value and the q-axis voltage control value are determined. The calculation process for the d-axis voltage control value and the q-axis voltage control value is as follows: Among them, u d The d-axis voltage control value, u q This is the q-axis voltage control value.

7. The motor control method according to any one of claims 1 to 3, characterized in that, The voltage synthesis module includes a first voltage model unit, a second voltage model unit, and a voltage synthesis unit; The first d-axis current command value, the first q-axis current command value, and the preset given value are input to the first voltage model unit to obtain the first d-axis voltage reference value and the first q-axis voltage reference value; The second d-axis current command value, the second q-axis current command value, and the preset given value are input to the second voltage model unit to obtain the second d-axis voltage reference value and the second q-axis voltage reference value; The first d-axis voltage reference value, the first q-axis voltage reference value, the second d-axis voltage reference value, and the second q-axis voltage reference value are input to the voltage synthesis unit to obtain the d-axis voltage control value and the q-axis voltage control value.

8. The motor control method according to claim 1, characterized in that, The step of inputting the actual values ​​of the first d-axis current, the first q-axis current, the second d-axis current, the second q-axis current, the d-axis voltage control value, the q-axis voltage control value, and the preset given value to the angle adjustment module to obtain the composite angle includes: The first actual value of the d-axis current, the first actual value of the q-axis current, the d-axis voltage control value, the q-axis voltage control value, and the preset given value are input to the angle adjustment module to obtain the first observation frequency; The actual value of the second d-axis current, the actual value of the second q-axis current, the d-axis voltage control value, the q-axis voltage control value, and the preset given value are input to the angle adjustment module to obtain the second observation frequency; The angle adjustment module converts and synthesizes the first observation frequency and the second observation frequency to obtain the synthesized angle.

9. The motor control method according to claim 8, characterized in that, The angle adjustment module includes a first phase-locked loop, a second phase-locked loop, a speed synthesis unit, and an angle calculation unit; The first actual value of the d-axis current, the first actual value of the q-axis current, the d-axis voltage control value, the q-axis voltage control value, and the preset given value are input to the first phase-locked loop to obtain the first observation frequency; The second d-axis current actual value, the second q-axis current actual value, the d-axis voltage control value, the q-axis voltage control value, and the preset given value are input to the second phase-locked loop to obtain the second observation frequency; The first observation frequency and the second observation frequency are input to the rotational speed synthesis unit to obtain the synthesized observation frequency; The synthetic observation frequency is input into the angle calculation unit to obtain the synthetic angle.

10. An air conditioner, characterized in that, It includes an indoor unit, an outdoor unit, and a motor control device, wherein the motor control device is used to perform the motor control method as described in any one of claims 1 to 9; The outdoor unit includes M fans, wherein the motor control device is used to control the M fans, where M is a positive integer greater than 1.

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