Method for controlling an electric machine and permanent magnet synchronous electric machine drive system

Abstract

The application provides a motor control method and a permanent magnet synchronous motor driving system. The method comprises the following steps: an effective back electromotive force observer determines an effective back electromotive force voltage amplitude of a motor, a rotor position of the motor and a rotating speed of the motor according to an output current and an output voltage of the motor, and then determines whether to send an injection signal to an injection current control module according to the effective back electromotive force voltage amplitude; if yes, the injection signal is sent to the injection current control module; the injection current control module responds to the injection signal, injects a current signal into the motor, inputs the rotor position of the motor and the rotating speed of the motor into a driving circuit, and finally controls the motor according to the rotor position of the motor and the rotating speed of the motor. The method of the application can realize the estimation of the rotor position and the rotating speed of the motor in the full speed range by using only one observer, and reduces the complexity and the debugging difficulty of system control.

Description

Technical Field

[0001] This application relates to the field of motor control technology, and more specifically, to a motor control method and a permanent magnet synchronous motor drive system. Background Technology

[0002] Built-in permanent magnet synchronous motor drive systems typically use extended back EMF observers to estimate the rotor position and speed of the motor. However, when the motor speed is close to zero, the amplitude of the extended back EMF under steady-state conditions will also be close to zero, which means that the extended back EMF observer cannot accurately estimate the rotor position and speed of the motor under zero-speed conditions.

[0003] In existing technologies, the high-frequency injection method is used to estimate the rotor position and speed of the motor under zero-low speed conditions, while an extended back EMF observer is used to estimate the rotor position and speed of the motor under medium- and high-speed conditions.

[0004] However, existing technologies involve switching between two control strategies, and the implementation of high-frequency injection methods usually requires the separate design of modulation and demodulation filters, which increases the complexity of the system and the difficulty of debugging. Summary of the Invention

[0005] The purpose of this application is to address the shortcomings of the prior art by providing a motor control method and a permanent magnet synchronous motor drive system, thereby solving the problems of high system complexity and difficult debugging caused by the use of two control strategies in the prior art permanent magnet synchronous motor drive system.

[0006] To achieve the above objectives, the technical solution adopted in this application is as follows: In a first aspect, this application provides a motor control method applied to a permanent magnet synchronous motor drive system, the permanent magnet synchronous motor drive system comprising: a motor, an effective back EMF observer, an injection current control module, and a drive circuit, the method comprising: The effective back EMF observer determines the effective back EMF voltage amplitude, rotor position, and rotational speed of the motor based on the motor's output current and output voltage. The effective back EMF observer determines whether to send an injection signal to the injection current control module based on the effective back EMF voltage amplitude. If so, it sends an injection signal to the injection current control module, and the injection current control module responds to the injection signal by injecting a current signal into the motor. The effective back EMF observer inputs the rotor position and the rotational speed of the motor into the drive circuit; The drive circuit controls the motor according to the rotor position and the motor speed.

[0007] Optionally, the effective back EMF observer determines the effective back EMF voltage amplitude, the rotor position, and the rotational speed of the motor based on the output current and output voltage of the motor, including: The effective back EMF observer determines the effective back EMF voltage amplitude based on the output current and the output voltage; The effective back EMF observer determines the rotor position and the rotational speed of the motor based on the effective back EMF voltage amplitude.

[0008] Optionally, the effective back EMF observer determines the effective back EMF voltage amplitude based on the output current and the output voltage, including: The effective back EMF voltage is determined based on the output voltage and the output current. The effective back EMF voltage amplitude is determined based on the effective back EMF voltage.

[0009] Optionally, the effective back EMF observer determines the rotor position and the rotational speed of the motor based on the effective back EMF voltage amplitude, including: The rotor position of the motor is determined based on the effective back EMF voltage amplitude; The rotational speed of the motor is determined based on the rotor position of the motor.

[0010] Optionally, the effective back EMF observer determines whether to send an injection signal to the injection current control module based on the effective back EMF voltage amplitude, including: If the effective back EMF voltage amplitude is less than or equal to a preset value, then an injection signal is sent to the injection current control module.

[0011] Optionally, after the effective back EMF observer determines whether to send an injection signal to the injection current control module based on the effective back EMF voltage amplitude, it further includes: If the effective back EMF voltage amplitude is greater than a preset value, then the injection signal to the injection current control module is stopped.

[0012] Optionally, the current signal is a direct-axis current signal with a slope that satisfies a preset condition.

[0013] Secondly, this application provides a permanent magnet synchronous motor drive system, the device comprising: a motor, an effective back EMF observer, an injection current drive circuit, and a drive circuit; wherein: The output terminal of the drive circuit is connected to the motor, the motor is connected to the input terminal of the effective back EMF observer, the first output terminal of the effective back EMF observer is connected to the input terminal of the injection current control module, the second output terminal of the effective back EMF observer is connected to the drive circuit, and the output terminal of the injection current control module is connected to the drive circuit. The effective back EMF observer is used to perform the steps performed by the effective back EMF observer in the motor control method as described in the first aspect; The injection current control module is used to perform the steps executed by the injection current control module in the motor control method as described in the first aspect; The drive circuit is used to perform the steps performed by the drive circuit in the motor control method as described in the first aspect; The motor is used to perform the steps performed by the motor in the motor control method as described in the first aspect.

[0014] Optionally, the drive circuit includes: a regulation and conversion module, a pulse width modulation module, and an inverter; The first input terminal of the adjustment and conversion module is connected to the second output terminal of the effective back EMF observer, and the second input terminal of the adjustment and conversion module is connected to the output terminal of the injection current control module. The output terminal of the adjustment and conversion module is connected to the input terminal of the pulse width modulation module, and the output terminal of the pulse width modulation module is connected to the output terminal of the inverter. The output terminal of the inverter is connected to the motor, and the third input terminal of the adjustment and conversion module is connected to the output terminal of the inverter.

[0015] Optionally, the adjustment and conversion module includes: a first conversion module, a second conversion module, a speed regulator, and a current regulator; The first input terminal of the first conversion module is connected to the second output terminal of the effective back EMF observer. The second input terminal of the first conversion module is connected to the output terminal of the inverter as the third input terminal of the adjustment conversion module. The first output terminal of the first conversion module is connected to one end of the speed regulator. The second output terminal of the first conversion module is connected to the input terminal of the current regulator. The other end of the speed regulator is connected to the input end of the current regulator, and the output end of the current regulator is connected to the input end of the second conversion module. The output of the second conversion module is connected to the input of the pulse width modulation module, and the output of the pulse width modulation module is connected to the input of the inverter.

[0016] The beneficial effects of this application are: by determining the effective back EMF voltage amplitude through an effective back EMF observer, and injecting a current signal into the motor based on the effective back EMF voltage amplitude during motor operation, the rotor position and speed of the motor can be estimated across the entire speed range using only one observer, eliminating the need for additional modulation and demodulation filters and avoiding the switching of multiple control strategies. Compared to existing technologies, this not only reduces the complexity of permanent magnet synchronous motor drive system control but also lowers the difficulty of debugging. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This paper presents a schematic diagram of the architecture of a permanent magnet synchronous motor drive system according to an embodiment of this application. Figure 2 A flowchart of a motor control method provided in an embodiment of this application is shown; Figure 3 An example diagram of a direct-axis current signal provided in an embodiment of this application is shown; Figure 4 This application provides a flowchart illustrating how to determine the effective back EMF voltage amplitude, motor rotor position, and rotational speed according to an embodiment of the present application. Figure 5 This application provides a flowchart for determining the effective back EMF voltage amplitude according to an embodiment of the present application. Figure 6 This application provides a flowchart illustrating how to determine the position and speed of a motor rotor according to an embodiment of the present application. Figure 7 This paper presents an overall flowchart of a motor control method according to an embodiment of the present application; Figure 8 A schematic diagram of a permanent magnet synchronous motor drive system architecture provided in an embodiment of this application is shown; Figure 9 A schematic diagram of another permanent magnet synchronous motor drive system architecture provided in an embodiment of this application is shown; Figure 10 This paper presents an architectural block diagram of a permanent magnet synchronous motor drive system according to an embodiment of this application. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. It should be understood that the accompanying drawings in this application are for illustrative and descriptive purposes only and are not intended to limit the scope of protection of this application. Furthermore, it should be understood that the schematic drawings are not drawn to scale. The flowcharts used in this application illustrate operations implemented according to some embodiments of this application. It should be understood that the operations in the flowcharts may not be implemented in sequence, and steps without logical contextual relationships may be reversed or implemented simultaneously. In addition, those skilled in the art, guided by the content of this application, may add one or more other operations to the flowcharts, or remove one or more operations from the flowcharts.

[0020] Furthermore, the described embodiments are merely some, not all, of the embodiments of this application. The components of the embodiments of this application described and illustrated herein can typically be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0021] It should be noted that the term "comprising" will be used in the embodiments of this application to indicate the presence of the features declared thereafter, but does not exclude the addition of other features.

[0022] When controlling a motor, it is necessary to obtain the rotor position and speed of the motor. Currently, an extended back EMF observer is usually used to estimate the rotor position and speed of the motor. However, when the motor speed is close to zero, the amplitude of the extended back EMF under steady-state conditions will also be close to zero, which means that the extended back EMF observer cannot accurately estimate the rotor position and speed of the motor under zero-speed conditions.

[0023] To facilitate understanding, the construction process of the extended back potential observer will be explained first. The extended back potential observer can be constructed using the following formulas (1)-(3).

[0024] (1) (2) (3) in, The effective back electromotive force voltage component in the stationary coordinate system is given by the equation. = [ , ] T , It is the component of the motor stator voltage in the stationary coordinate system. It is the component of the motor stator current in the stationary coordinate system. It is the direct-axis inductance of the motor. R is the quadrature-axis inductance of the motor, and R is the stator resistance of the motor. It is the motor speed. It refers to the rotor position of the motor. and These are the direct-axis current and quadrature-axis current of the motor in the synchronous rotating coordinate system, respectively. It is the permanent magnet flux linkage of the motor.

[0025] To address the aforementioned issues, existing technologies have proposed employing different control strategies for zero-speed and high-speed operating conditions. Specifically, a high-frequency injection method is used to estimate the rotor position and speed of the motor under zero-speed conditions, while an extended back-EMF observer is used to estimate the rotor position and speed under high-speed conditions.

[0026] However, this approach involves switching between two control strategies, and the implementation of the high-frequency injection method usually requires the separate design of a modulation and demodulation filter, which undoubtedly increases the complexity of the system and the difficulty of debugging.

[0027] Based on the above problems, this application proposes a motor control method that can estimate the rotor position and speed of the motor under zero-speed, low-speed, and medium-to-high-speed operating conditions using only one observation method. While achieving estimation across the entire speed range, it reduces the complexity and debugging difficulty of the system.

[0028] The method described in this application can be applied to... Figure 1 In the permanent magnet synchronous motor drive system shown, refer to Figure 1 The system includes a motor, an effective back EMF observer, an injection current control module, and a drive circuit. The effective back EMF observer is used to observe the rotor position and speed of the motor. The injection current control module is used to inject current into the drive circuit based on the observation results of the effective back EMF observer. The drive circuit is used to control the motor based on the observation results of the effective back EMF observer and the injection current.

[0029] Next, combine Figure 2 The motor control method of this application will be described, such as... Figure 2 As shown, the method includes: S201: The effective back EMF observer determines the effective back EMF voltage amplitude, rotor position, and speed of the motor based on the motor's output current and output voltage.

[0030] Reference Figure 1As one possible implementation, an effective back EMF observer can be connected to the motor and can acquire the motor's output current and output voltage in real time.

[0031] It should be understood that an effective back EMF observer can also obtain the motor's output current and output voltage through current sampling circuits and voltage sampling circuits. This application does not limit the specific methods of obtaining the output current and output voltage.

[0032] The effective back potential observer in this application can be constructed by the following equations (4) and (5).

[0033] (4) (5) Compared to the extended back EMF observer constructed by the above formulas (1)-(3), the amplitudes of the two under steady-state conditions are the same. Therefore, under the high-speed operating conditions of the motor, the effective back EMF observer constructed by the above formulas (4) and (5) is equivalent to the extended back EMF observer.

[0034] In this application, the effective back EMF observer constructed by the above formulas (1) and (2) can be used to estimate the rotor position and speed of the motor. The output voltage and output current of the motor are used as the input parameters of the effective back EMF observer. The effective back EMF observer can first estimate the effective back EMF voltage amplitude, and then determine the rotor position and speed of the motor under the current output voltage and output current based on the effective back EMF voltage amplitude.

[0035] The relationship between the effective back EMF voltage amplitude and the effective back EMF voltage can be expressed as shown in equation (6).

[0036] (6) Based on this, the effective back EMF voltage magnitude can be expressed as the following equation (7).

[0037] (7) S202: The effective back EMF observer determines whether to send an injection signal to the injection current control module based on the effective back EMF voltage amplitude. If so, it sends an injection signal to the injection current control module, which responds to the injection signal and injects a current signal into the motor.

[0038] The injection signal is used to instruct the injection current control module to inject a current signal into the drive circuit. The current signal can be a direct-axis current signal with a slope that meets a preset condition.

[0039] It should be noted that for built-in permanent magnet synchronous motors, the injected direct-axis current signal has little impact on its electromagnetic torque. In order to avoid the influence of inverter dead-zone nonlinearity, a certain DC component needs to be added to the injected direct-axis current signal.

[0040] For example, the current signal can be Figure 3 The direct-axis current signal shown is given, where i d0 For the DC component of the injected signal, Δi d Let t be the amplitude of the triangular wave component of the injected signal. dq The period of the triangular wave component of the injected signal.

[0041] From equation (7) above, it can be seen that the effective back EMF voltage amplitude It consists of three parts. When the motor speed is high, the effective back EMF voltage amplitude... The first and third items account for a much larger proportion than the second item; and when the motor speed is extremely low, the effective back EMF voltage amplitude... The first and third terms will approach zero; when the motor speed is zero, the effective back EMF voltage amplitude... The first and third terms will equal zero.

[0042] Based on this, if a current signal is injected into the motor under zero-speed operating conditions, then according to equation (7), even if the motor speed is zero, the effective back EMF voltage amplitude is... It is also non-zero, therefore the effective back EMF observer in this application can estimate the rotor position and speed of the motor under all operating conditions, including zero low-speed conditions and medium-high speed conditions.

[0043] S203: The effective back EMF observer inputs the rotor position and speed of the motor into the drive circuit.

[0044] The drive circuit may include a regulator, a conversion module, a pulse width modulation module, and an inverter.

[0045] S204: The drive circuit controls the motor based on the rotor position and the motor speed.

[0046] After the motor starts, the drive circuit can control the motor based on the rotor position and speed of the previous moment and the rotor position and speed of the current moment.

[0047] It should be noted that the initial position of the motor can be obtained before the motor starts. For example, the initial position of the motor can be identified offline before the motor starts using a sensorless solution for magnetic field orientation control.

[0048] For example, the drive circuit can use the motor speed as feedback for closed-loop speed control, adjust the motor speed according to the preset motor speed value, perform coordinate transformation on the rotor position of the motor, and perform field-oriented control, so that the inverter adjusts the output voltage according to the rotor position and speed of the motor to achieve motor control.

[0049] In this embodiment, the effective back EMF observer determines the effective back EMF voltage amplitude, rotor position, and rotational speed of the motor based on the motor's output current and output voltage. Then, based on the effective back EMF voltage amplitude, it determines whether to send an injection signal to the injection current control module. If so, it sends an injection signal to the injection current control module. The injection current control module responds to the injection signal and injects a current signal into the motor, inputting the motor's rotor position and rotational speed into the drive circuit. Finally, the drive circuit controls the motor based on the motor's rotor position and rotational speed.

[0050] The method presented in this application determines the effective back EMF voltage amplitude using an effective back EMF observer and injects a current signal into the motor based on the effective back EMF voltage amplitude during motor operation. Using only one observer, the rotor position and speed of the motor can be estimated across the entire speed range without the need for additional modulation / demodulation filters or switching between multiple control strategies. Compared to existing technologies, this not only reduces the complexity of permanent magnet synchronous motor drive system control but also simplifies debugging.

[0051] The following is a further explanation of how the aforementioned effective back EMF observer determines the effective back EMF voltage amplitude, rotor position, and speed of the motor based on the output current and output voltage. Figure 4 As shown, the above step S201 includes: S401: The effective back EMF observer determines the effective back EMF voltage amplitude based on the output current and output voltage.

[0052] S402: The effective back EMF observer determines the rotor position and speed of the motor based on the effective back EMF voltage amplitude.

[0053] It should be noted that the effective back EMF voltage amplitude in this application can be estimated by the effective back EMF observer based on the output voltage and output current, and is similar to the actual effective back EMF voltage amplitude of the motor, or can characterize the magnitude of the actual effective back EMF voltage amplitude of the motor.

[0054] After determining the effective back EMF voltage amplitude, the effective back EMF observer can estimate the rotor position and motor speed of the motor based on the estimated effective back EMF voltage amplitude.

[0055] The following is a further explanation of how the effective back EMF observer determines the effective back EMF voltage amplitude based on the output current and output voltage in step S401 above. Figure 5 As shown, the above S401 step includes: S501: The effective back EMF observer determines the effective back EMF voltage based on the output voltage and output current.

[0056] For example, the output voltage is expressed as The output current is expressed as Then the effective back EMF voltage It can be obtained according to the following formula (8).

[0057] (8) S502: The effective back EMF observer determines the effective back EMF voltage amplitude based on the effective back EMF voltage.

[0058] Optionally, the effective back EMF voltage can be calculated according to the following formula (9) to obtain the effective back EMF voltage amplitude. .

[0059] (9) in, and for Two components in the coordinate system.

[0060] The following is a further explanation of how the effective back EMF observer determines the rotor position and speed of the motor based on the effective back EMF voltage amplitude. Figure 6 As shown, step S402 above includes: S601: The effective back EMF observer determines the rotor position of the motor based on the effective back EMF voltage amplitude.

[0061] After obtaining the effective back EMF voltage amplitude based on equation (9) above, the effective back EMF voltage amplitude can be calculated based on equation (10) below to obtain the rotor position of the motor. .

[0062] (10) S602: The effective back EMF observer determines the motor speed based on the rotor position of the motor.

[0063] Optionally, depending on the rotor position of the motor The motor speed can be determined by the following formula (11).

[0064] (11) In order to balance the operating efficiency of the motor, the direct-axis current signal can be not injected when the effective back EMF voltage amplitude is large, that is, when the motor speed is high, but the direct-axis current signal can be injected only when the effective back EMF voltage amplitude is small.

[0065] The above-mentioned effective back EMF observer determines whether to send an injection signal to the injection current control module based on the effective back EMF voltage amplitude, including: If the effective back EMF voltage amplitude is less than or equal to the preset value, then an injection signal is sent to the injection current control module.

[0066] The preset values ​​can be set by the designers based on historical data, and the specific values ​​are not limited in this application.

[0067] It should be noted that the existing solution, which judges the magnitude of the effective back EMF voltage based on the motor speed, ignores the problem of demagnetization of the permanent magnet in the built-in permanent magnet synchronous motor. That is, if the permanent magnet of the motor is demagnetized, there will be a problem that the motor speed is high but the magnitude of the effective back EMF voltage is still small.

[0068] Based on this, this application directly uses the effective back EMF voltage amplitude estimated by the effective back EMF observer to determine the magnitude of the effective back EMF voltage amplitude, thereby further determining whether a direct-axis current signal injection is required.

[0069] As another possible implementation, after the effective back EMF observer determines whether to send an injection signal to the injection current control module based on the effective back EMF voltage amplitude, it also includes: If the effective back EMF voltage amplitude is greater than the preset value, then the injection signal to the injection current control module will be stopped.

[0070] When the effective back EMF voltage amplitude is greater than the preset value, in order to ensure the operating efficiency of the motor, the injection signal to be sent to the injection current control module can be stopped, so that the injection current control module stops injecting current signal into the drive circuit.

[0071] like Figure 7 The diagram shown is a flowchart of the overall motor control method of this application. (Refer to...) Figure 7 Even after the injection signal is stopped, the effective back EMF observer will still acquire the motor's output voltage and output current in real time, and calculate the effective back EMF voltage amplitude, the motor's rotor position, and the speed.

[0072] It should be understood that during the operation of the motor, the effective back EMF voltage amplitude is constantly changing. When the effective back EMF voltage amplitude is less than or equal to the preset value, an injection signal is continuously sent to the injection current control module so that the injection current control module can continue to inject current signals into the drive circuit.

[0073] Next, combine Figure 8 The permanent magnet synchronous motor drive system of this application will be described, such as... Figure 8 As shown, the permanent magnet synchronous motor drive system includes a motor, an effective back EMF observer, an injection current drive circuit, and a drive circuit.

[0074] Reference Figure 8 The output of the drive circuit is connected to the motor, the motor is connected to the input of the effective back EMF observer, the first output of the effective back EMF observer is connected to the input of the injection current control module, the second output of the effective back EMF observer is connected to the drive circuit, and the output of the injection current control module is connected to the drive circuit.

[0075] Optionally, the first output of the effective back EMF observer is used to send an injection signal to the injection current control module, and the second output is used to send the rotor position and speed of the motor to the drive circuit.

[0076] Figure 8 The principle of the permanent magnet synchronous motor drive system shown is similar to the motor control method described in the embodiments of this application. Therefore, the implementation of the system can refer to the implementation of the method, and the repeated parts will not be described again.

[0077] like Figure 9 As shown, Figure 8 The drive circuit includes a regulation and conversion module, a pulse width modulation module, and an inverter.

[0078] Reference Figure 9 The first input terminal of the adjustment conversion module is connected to the second output terminal of the effective back EMF observer, and the second input terminal of the adjustment conversion module is connected to the output terminal of the injection current control module.

[0079] The output of the regulating conversion module is connected to the input of the pulse width modulation module, and the output of the pulse width modulation module is connected to the output of the inverter.

[0080] The inverter's output is connected to the motor, and the third input of the adjustment and conversion module is connected to the inverter's output.

[0081] Furthermore, Figure 9 The adjustment and conversion module includes: a first conversion module, a second conversion module, a speed regulator, and a current regulator.

[0082] Reference Figure 10 This is a schematic diagram of the architecture of a permanent magnet synchronous motor drive system, in which: The first input terminal of the first conversion module is connected to the second output terminal of the effective back EMF observer. The second input terminal of the first conversion module is connected to the output terminal of the inverter as the third input terminal of the adjustment conversion module. The first output terminal of the first conversion module is connected to one end of the speed regulator. The second output terminal of the first conversion module is connected to the input terminal of the current regulator.

[0083] The other end of the speed regulator is connected to the input of the current regulator, and the output of the current regulator is connected to the input of the second conversion module.

[0084] The output of the second conversion module is connected to the input of the pulse width modulation module, and the output of the pulse width modulation module is connected to the input of the inverter.

[0085] Reference Figure 10 The effective back EMF observer acquires the output voltage and output current of the motor in real time, and estimates the effective back EMF voltage amplitude, the rotor position of the motor, and the motor speed. Then, when the effective back EMF voltage amplitude is less than or equal to the preset value, it sends an injection signal to the injection current control module and sends the estimated rotor position and motor speed of the motor to the first conversion module and the second conversion module of the drive circuit.

[0086] The injection current control module injects a current signal into the drive circuit based on the injection signal. The drive circuit adjusts the inverter's output voltage according to the injected current signal, the motor's rotor position, and the motor's speed, thereby controlling the motor.

[0087] During this process, the effective back EMF observer continuously acquires the motor's output voltage and current in real time and repeats the above process to ensure the normal operation of the motor. The method of this application uses an observer without sensors and can control the motor without strategy switching, ensuring the normal operation of the motor under operating conditions across the full speed range.

[0088] Optional, Figure 8 The permanent magnet synchronous motor drive system shown: An effective back EMF observer is used to obtain the motor's output current and output voltage; The effective back EMF observer is also used to determine the effective back EMF voltage amplitude, rotor position, and speed of the motor based on the output current and output voltage. The effective back EMF observer is also used to determine whether to send an injection signal to the injection current control module based on the effective back EMF voltage amplitude. If so, it sends an injection signal to the injection current control module, which responds to the injection signal and injects a current signal into the motor. An effective back EMF observer is also used to input the rotor position and speed of the motor into the drive circuit. The drive circuit is used to control the motor based on the rotor position and the motor speed.

[0089] Optionally, the effective back potential observer is also used for: The effective back EMF voltage amplitude is determined based on the output current and the output voltage. The rotor position and the speed of the motor are determined based on the effective back EMF voltage amplitude.

[0090] Optionally, the effective back potential observer is also used for: The effective back EMF voltage is determined based on the output voltage and the output current. The effective back EMF voltage amplitude is determined based on the effective back EMF voltage.

[0091] Optionally, the effective back potential observer is also used for: The rotor position of the motor is determined based on the effective back EMF voltage amplitude; The rotational speed of the motor is determined based on the rotor position of the motor.

[0092] Optionally, the effective back potential observer is also used for: If the effective back EMF voltage amplitude is less than or equal to a preset value, then an injection signal is sent to the injection current control module.

[0093] Optionally, the effective back potential observer is also used for: If the effective back EMF voltage amplitude is greater than a preset value, then the injection signal to the injection current control module is stopped.

[0094] Optionally, the current signal is a direct-axis current signal with a slope that satisfies a preset condition.

[0095] This application's embodiment determines the effective back EMF voltage amplitude using an effective back EMF observer and injects a current signal into the motor based on the effective back EMF voltage amplitude during motor operation. Using only one observer, the rotor position and speed of the motor can be estimated across the entire speed range, eliminating the need for additional modulation / demodulation filters and avoiding the switching between multiple control strategies. Compared to existing technologies, this not only reduces the complexity of the permanent magnet synchronous motor drive system control but also lowers the debugging difficulty.

[0096] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working process of the system described above can be referred to the corresponding process in the method embodiments, and will not be repeated here. In the several embodiments provided in this application, it should be understood that the disclosed system and method can be implemented in other ways. The system embodiments described above are merely illustrative. For example, the division of modules is only a logical functional division, and in actual implementation, there may be other division methods. Furthermore, multiple modules or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the displayed or discussed mutual coupling or direct coupling or communication connection can be an indirect coupling or communication connection through some communication interfaces, devices, or modules, and can be electrical, mechanical, or other forms.

[0097] 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.

[0098] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any changes 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.

Claims

1. A motor control method, characterized in that, The method is applied to a permanent magnet synchronous motor drive system, the permanent magnet synchronous motor drive system comprising: a motor, an effective back EMF observer, an injection current control module, and a drive circuit; the method includes: The effective back EMF observer determines the effective back EMF voltage amplitude, rotor position, and rotational speed of the motor based on the motor's output current and output voltage. The effective back EMF observer determines whether to send an injection signal to the injection current control module based on the effective back EMF voltage amplitude. If so, it sends an injection signal to the injection current control module. The injection current control module responds to the injection signal and injects a current signal into the motor. The current signal is a direct-axis current signal with a slope that meets a preset condition. The effective back EMF observer inputs the rotor position and the rotational speed of the motor into the drive circuit; The drive circuit controls the motor according to the rotor position and the motor speed; The effective back EMF observer determines whether to send an injection signal to the injection current control module based on the effective back EMF voltage amplitude, including: If the effective back EMF voltage amplitude is less than or equal to a preset value, then it is determined to send an injection signal to the injection current control module; If the effective back EMF voltage amplitude is greater than a preset value, then the injection signal to the injection current control module is stopped.

2. The method according to claim 1, characterized in that, The effective back EMF observer determines the effective back EMF voltage amplitude, rotor position, and rotational speed of the motor based on the motor's output current and output voltage, including: The effective back EMF observer determines the effective back EMF voltage amplitude based on the output current and the output voltage; The effective back EMF observer determines the rotor position and the rotational speed of the motor based on the effective back EMF voltage amplitude.

3. The method according to claim 2, characterized in that, The effective back EMF observer determines the effective back EMF voltage amplitude based on the output current and the output voltage, including: The effective back EMF observer determines the effective back EMF voltage based on the output voltage and the output current; The effective back EMF observer determines the amplitude of the effective back EMF voltage based on the effective back EMF voltage.

4. The method according to claim 2, characterized in that, The effective back EMF observer determines the rotor position and rotational speed of the motor based on the effective back EMF voltage amplitude, including: The effective back EMF observer determines the rotor position of the motor based on the effective back EMF voltage amplitude; The effective back EMF observer determines the rotational speed of the motor based on the rotor position of the motor.

5. A permanent magnet synchronous motor drive system, characterized in that, include: The components include a motor, an effective back EMF observer, an injection current control module, and a drive circuit; among which: The output terminal of the drive circuit is connected to the motor, the motor is connected to the input terminal of the effective back EMF observer, the first output terminal of the effective back EMF observer is connected to the input terminal of the injection current control module, the second output terminal of the effective back EMF observer is connected to the drive circuit, and the output terminal of the injection current control module is connected to the drive circuit. The effective back EMF observer is used to perform the steps performed by the effective back EMF observer in the motor control method as described in any one of claims 1-4; The injection current control module is used to perform the steps executed by the injection current control module in the motor control method as described in any one of claims 1-4; The drive circuit is used to perform the steps executed by the drive circuit in the motor control method as described in any one of claims 1-4; The motor is used to perform the steps performed by the motor in the motor control method as described in any one of claims 1-4.

6. The system according to claim 5, characterized in that, The drive circuit includes: a regulation and conversion module, a pulse width modulation module, and an inverter; The first input terminal of the adjustment and conversion module is connected to the second output terminal of the effective back EMF observer, and the second input terminal of the adjustment and conversion module is connected to the output terminal of the injection current control module. The output terminal of the adjustment and conversion module is connected to the input terminal of the pulse width modulation module, and the output terminal of the pulse width modulation module is connected to the output terminal of the inverter. The output terminal of the inverter is connected to the motor, and the third input terminal of the adjustment and conversion module is connected to the output terminal of the inverter.

7. The system according to claim 6, characterized in that, The adjustment and conversion module includes: a first conversion module, a second conversion module, a speed regulator, and a current regulator; The first input terminal of the first conversion module is connected to the second output terminal of the effective back EMF observer. The second input terminal of the first conversion module is connected to the output terminal of the inverter as the third input terminal of the adjustment conversion module. The first output terminal of the first conversion module is connected to one end of the speed regulator. The second output terminal of the first conversion module is connected to the input terminal of the current regulator. The other end of the speed regulator is connected to the input end of the current regulator, and the output end of the current regulator is connected to the input end of the second conversion module. The output of the second conversion module is connected to the input of the pulse width modulation module, and the output of the pulse width modulation module is connected to the input of the inverter.

Images