Full-speed-domain position-free control method and device for permanent magnet motor

Abstract

The invention relates to the technical field of permanent magnet motors, and discloses a permanent magnet motor full-speed-domain position-free control method and device, and the method comprises the steps: obtaining a rotating speed feedback value under a rotor coordinate system of a motor; based on the rotating speed feedback value under the rotor coordinate system and the rotating speed instruction under the virtual coordinate system, establishing a rotating speed ring by using IF control; when the observed rotating speed does not track the instruction rotating speed, the output of the rotating speed ring reaches a saturation upper limit and is a constant value until the rotating speed reaches an identifiable and traceable rotating speed instruction, at the moment, the rotating speed ring output instruction is adjusted according to the condition of a rotating speed feedback value, and the rotating speed ring enters a desaturation process; finally, the position signal is converted from the instruction rotating speed generation to the sliding-mode observer observation. The improved switching strategy is realized through desaturation of the rotating speed ring, no extra switching strategy design is needed, and the method has certain adaptability to load conversion.

Description

Technical Field

[0001] The present invention relates to the technical field of permanent magnet motors, and in particular to a method and device for position-free control of a permanent magnet motor in full speed range. Background Art

[0002] The mechanical sensorless control strategy can improve the reliability of the motor control system and reduce the risk of instability of the high-speed motor shaft system. It can usually be divided into two categories according to the applicable speed range: low-speed sensorless strategy and high-speed sensorless strategy. The low-speed domain uses the salient pole characteristics or saturated salient pole characteristics of the motor, which is more difficult. More commonly, a simpler low-speed and speedless method has been widely used I / F control method. Since the control strategies used in the low-speed domain and the high-speed domain are different, it is necessary to set the switching strategy between the two to ensure the stability of the control system.

[0003] The prior art mostly uses the current loop command and the reference position signal to start. When it comes to the switching turning speed, if the speed needs to be controlled, the current loop needs to be switched to the speed. However, the speed loop control output state can easily cause the system to have overcurrent or switching failure. Summary of the invention

[0004] In view of this, the present invention provides a method and device for position-free control of a permanent magnet motor in full speed range, so as to solve the problem of how to switch the control strategies adopted in the low speed range and the high speed range.

[0005] In a first aspect, the present invention provides a full-speed domain position-free control method for a permanent magnet motor, comprising: obtaining a speed feedback value in a rotor coordinate system of the motor, wherein the speed feedback value is estimated by an observer; based on the speed feedback value in the rotor coordinate system and the speed command in the virtual coordinate system, using IF control to establish a speed loop control to rotate the motor; when the speed feedback value cannot track the speed command, based on the speed command, controlling the speed loop to output a current command from a constant saturation upper limit to a current loop to form a constant current command; when the speed feedback value can track the speed command, based on the speed feedback value and the speed command, controlling the speed loop to output a current command to a current loop; when the virtual coordinate system does not coincide with the rotor coordinate system, the current loop adopts a coordinate transformation angle obtained by integrating the speed command value, and outputs a voltage reference value based on the constant saturation upper limit of the current command or the current command; when the virtual coordinate system coincides with the rotor coordinate system, the current loop adopts a coordinate transformation angle estimated by the observer, and outputs a voltage reference value based on the speed feedback value; based on the voltage reference value, a switching sequence of the converter of the motor is obtained, and the switching sequence is used to control the on and off of the power device of the converter.

[0006] In the present invention, when the observed speed has not tracked the command speed, the speed loop output reaches the saturation upper limit, and its output is a constant value until the speed reaches a recognizable and can track the speed command. At this time, the speed loop output command is adjusted according to the speed feedback value, and the speed loop enters the desaturation process, and finally completes the position signal from the command speed to the position signal observed by the sliding mode observer. The improved switching strategy is realized by the desaturation of the speed loop, without the need for additional switching strategy design and has a certain adaptability to load transformation.

[0007] In an optional embodiment, the process of obtaining the speed feedback value of the motor includes: collecting the three-phase current of the motor's inverter; performing Clarke transformation on the three-phase current to obtain the current in the αβ coordinate system; and calculating the speed feedback value based on the current in the virtual coordinate system using an adaptive sliding film observer.

[0008] In an optional embodiment, the process of establishing a speed loop using IF control includes: when the speed feedback value cannot track the speed command, PI adjustment is performed on the speed command to obtain the q-axis current; based on the q-axis current and the speed command, the IF control is used to obtain the constant saturation upper limit of the current command.

[0009] In an optional embodiment, the process of establishing a speed loop using IF control includes: when the speed feedback value can track the speed command, PI adjustment is performed on the difference between the speed feedback value and the speed command to obtain the q-axis current; based on the q-axis current and the speed command, the current command is obtained using IF control.

[0010] In an optional implementation, a switching sequence of the converter is obtained by using space vector modulation based on a voltage reference value.

[0011] In a second aspect, the present invention provides a permanent magnet motor full-speed domain position-free control device, including: a speed observer, which is used to obtain a speed feedback value in the rotor coordinate system of the motor, and the speed feedback value is estimated by the observer; a speed loop, which is used to determine whether the speed feedback value can track the speed instruction; when the speed feedback value cannot track the speed instruction, based on the speed instruction, the speed loop outputs a current instruction constant saturation upper limit to the current loop; when the speed feedback value can track the speed instruction, based on the speed feedback value and the speed instruction, the speed loop outputs a current instruction to the current loop; the current loop is used when the virtual coordinate system is not aligned with the rotor coordinate system When the virtual coordinate system and the rotor coordinate system coincide, the current loop outputs a voltage reference value based on the constant saturation upper limit of the current command or the rotor angle command; when the virtual coordinate system and the rotor coordinate system coincide, the current loop outputs a voltage reference value based on the speed feedback value; a modulation module, which is used to obtain a switching sequence of the converter of the motor based on the voltage reference value, and the switching sequence is used to control the on and off of the power device of the converter; a switching module, which is used to transmit the speed feedback value to the current loop when the virtual coordinate system and the rotor coordinate system coincide; when the virtual coordinate system does not coincide with the rotor coordinate system, the constant saturation upper limit of the current command or the current command is transmitted to the current loop;

[0012] In an optional embodiment, the speed observer includes: a Clarke converter, which is used to collect the three-phase current of the motor converter; performing a Clarke transform on the three-phase current to obtain the current in the αβ coordinate system; and an adaptive sliding film observer, which is used to calculate the speed feedback value based on the current in the virtual coordinate system.

[0013] In an optional embodiment, the speed loop includes: a subtractor, which is used to subtract the speed feedback value from the speed command; a PI regulator, which is used to perform PI regulation on the speed command to obtain the q-axis current when the speed feedback value cannot track the speed command; when the speed feedback value can track the speed command, perform PI regulation on the difference between the speed feedback value and the speed command to obtain the q-axis current; an IF control module, which is used to obtain a constant saturation upper limit of the current command or a current command based on the q-axis current and the speed command.

[0014] In a third aspect, the present invention provides a computer device, comprising: a memory and a processor, the memory and the processor being communicatively connected to each other, the memory storing computer instructions, and the processor executing the method for position-free control of a permanent magnet motor in full speed range according to the first aspect or any corresponding embodiment thereof by executing the computer instructions.

[0015] In a fourth aspect, the present invention provides a computer-readable storage medium having computer instructions stored thereon, the computer instructions being used to enable a computer to execute the method for position-free control of a permanent magnet motor in full speed range according to the first aspect or any corresponding embodiment thereof. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 is a flow chart of a method for position-free control of a permanent magnet motor in full speed range according to an embodiment of the present invention;

[0018] Figure 2 is a control block diagram of a method for position-free control of a permanent magnet motor in full speed range according to an embodiment of the present invention;

[0019] Figure 3 It is a schematic diagram of the hardware structure of a computer device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0021] According to an embodiment of the present invention, an embodiment of a method for position-free control of a permanent magnet motor in full speed range is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0022] In this embodiment, a method for position-free control of a permanent magnet motor in full speed range is provided. Figure 1 As shown, including:

[0023] Step S1: obtaining a speed feedback value of the motor in a rotor coordinate system, wherein the speed feedback value is estimated by an observer.

[0024] Specifically, the present embodiment sets a speed loop and a current loop, the speed loop outputs a speed feedback value as a measured value when the motor speed can track the speed command, and the speed loop outputs a rotor angle command according to the measured value and the speed command.

[0025] Optionally, the control block diagram of this embodiment is as follows: Figure 2As shown in FIG. 1 , the process of obtaining the speed feedback value of the motor includes: (1) collecting the three-phase current of the motor converter; (2) performing Clarke transformation on the three-phase current to obtain the current in the αβ coordinate system; (3) based on the current in the virtual coordinate system, using the adaptive sliding film observer to calculate the speed feedback value ω est .

[0026] Step S21: Based on the speed feedback value in the rotor coordinate system and the speed command in the virtual coordinate system, the speed loop control is established by using IF control to rotate the motor.

[0027] Specifically, the speed loop includes a subtractor, a PI regulator and an IF control module. The IF control module is a mature current-power ratio control method in the relevant technology, which will not be described here. The subtractor is used to subtract the speed feedback value from the speed command, and the PI regulator is used to proportionally integrate the difference to obtain the d-axis current. The IF outputs the current command to the current loop based on the d-axis current.

[0028] Specifically, the current command required for IF control is provided by the speed loop. The characteristic that the speed value observed by the observer in the low-speed or zero-speed area is relatively small is used to construct a real-time speed loop to form a double closed-loop control with the current loop. The speed feedback value of the speed loop is provided by the observer, and the command value is a constant value, which can be provided by the host computer.

[0029] Step S3: When the speed feedback value cannot track the speed command, based on the speed command, the speed loop is controlled to output the current command to the constant saturation upper limit to the current loop to form a constant current command; when the speed feedback value can track the speed command, based on the speed feedback value and the speed command, the speed loop is controlled to output the current command to the current loop.

[0030] Optionally, the process of establishing a speed loop using IF control includes: when the speed feedback value cannot track the speed command, performing PI adjustment on the speed command to obtain the q-axis current; based on the q-axis current and the speed command, using IF control to obtain a constant saturation upper limit of the current command.

[0031] Optionally, the process of establishing a speed loop using IF control includes: when the speed feedback value can track the speed command, performing PI adjustment on the difference between the speed feedback value and the speed command to obtain the q-axis current; based on the q-axis current and the speed command, using IF control to obtain the current command.

[0032] Specifically, when the observed speed has not tracked the command speed, the speed loop output reaches the saturation upper limit, and its output is a constant value until the speed reaches a point where the adaptive sliding mode observer can identify and track the speed command. At this time, the speed loop output command is adjusted according to the speed feedback value, and the speed loop enters the desaturation process, and finally completes the transformation of the position signal from the command speed to the position signal observed by the sliding mode observer.

[0033] Step S4: When the virtual coordinate system does not coincide with the rotor coordinate system, the current loop adopts the coordinate transformation angle obtained by integrating the speed command value, and outputs the voltage reference value based on the current command steady-state saturation upper limit or the rotor angle command; when the virtual coordinate system coincides with the rotor coordinate system, the current loop adopts the coordinate transformation angle estimated by the observer, and outputs the voltage reference value based on the speed feedback value.

[0034] Alternatively, if Figure 2 As shown, when the virtual coordinate system does not coincide with the rotor coordinate system, the input end of Park is switched to end 1, and when the virtual coordinate system does not coincide with the rotor coordinate system, the input end of Park is switched to end 2.

[0035] Step S5: obtaining a switching sequence of the converter of the motor based on the voltage reference value, wherein the switching sequence is used to control the on and off of the power devices of the converter.

[0036] Optionally, based on the voltage reference value, space vector modulation is used to obtain a switching sequence of the converter, but this is only an example and is not intended to be limiting.

[0037] In this embodiment, a permanent magnet motor full-speed range position-free control device is also provided, which is used to implement the above-mentioned embodiments and preferred implementation modes, and the descriptions that have been made will not be repeated. As used below, the term "module" can implement a combination of software and / or hardware of a predetermined function. Although the devices described in the following embodiments are preferably implemented in software, the implementation of hardware, or a combination of software and hardware, is also possible and conceivable.

[0038] This embodiment provides a permanent magnet motor full-speed range position-free control device, including:

[0039] The speed observer is used to obtain a speed feedback value of the motor in a rotor coordinate system, wherein the speed feedback value is estimated by the observer.

[0040] The speed loop is used to determine whether the speed feedback value can track the speed command; when the speed feedback value cannot track the speed command, based on the speed command, the speed loop outputs a constant saturation upper limit of the current command to the current loop; when the speed feedback value can track the speed command, based on the speed feedback value and the speed command, the speed loop outputs a current command to the current loop.

[0041] The current loop is used to output a voltage reference value based on a constant saturation upper limit of a current command or a rotor angle command when the virtual coordinate system does not coincide with the rotor coordinate system; and output a voltage reference value based on a speed feedback value when the virtual coordinate system coincides with the rotor coordinate system.

[0042] Optionally, the current loop is as follows Figure 2The q-axis voltage reference value is obtained by the PI regulator of the speed loop, the current measurement value in the dq coordinate system is obtained by Park transformation of the measured three-phase current, the difference between the voltage reference value and the measurement value is PI-regulated, and finally the voltage reference value is obtained.

[0043] The modulation module is used to obtain a switching sequence of the converter of the motor based on a voltage reference value, and the switching sequence is used to control the on and off of the power devices of the converter.

[0044] The switching module is used to transmit the speed feedback value to the current loop when the virtual coordinate system coincides with the rotor coordinate system; when the virtual coordinate system does not coincide with the rotor coordinate system, the current command constant saturation upper limit or current command is transmitted to the current loop. Figure 2 As shown, the switching module is used to implement θ IF With θ est Switch between.

[0045] In some optional embodiments, such as Figure 2 As shown, the speed observer includes:

[0046] Clarke converter, which is used to collect the three-phase current of the converter of the motor; Clarke conversion is performed on the three-phase current to obtain the current in the αβ coordinate system;

[0047] The adaptive synovial observer is used to calculate the speed feedback value based on the current in the virtual coordinate system.

[0048] In some optional embodiments, such as Figure 2 As shown, the speed loop includes:

[0049] A subtractor, which is used to make a difference between the speed feedback value and the speed command;

[0050] The PI regulator is used to perform PI regulation on the speed command to obtain the q-axis current when the speed feedback value cannot track the speed command; when the speed feedback value can track the speed command, perform PI regulation on the difference between the speed feedback value and the speed command to obtain the q-axis current;

[0051] The IF control module is used to obtain a current command constant saturation upper limit or a current command based on the q-axis current and the speed command.

[0052] The permanent magnet motor full-speed range position-free control device in this embodiment is presented in the form of a functional unit, where the unit refers to an ASIC circuit, a processor and memory that executes one or more software or fixed programs, and / or other devices that can provide the above functions.

[0053] The further functional description of each of the above modules and units is the same as that of the above corresponding embodiments and will not be repeated here.

[0054] An embodiment of the present invention further provides a computer device having the above-mentioned permanent magnet motor full-speed range position-free control device.

[0055] See also Figure 3 , Figure 3 is a schematic diagram of the structure of a computer device provided by an optional embodiment of the present invention, such as Figure 3 As shown, the computer device includes: one or more processors 10, a memory 20, and interfaces for connecting various components, including high-speed interfaces and low-speed interfaces. Various components are connected to each other using different buses for communication, and can be installed on a common mainboard or installed in other ways as needed. The processor can process the instructions executed in the computer device, including instructions stored in or on the memory to display the graphical information of the GUI on an external input / output device (such as, a display device coupled to the interface). In some optional embodiments, if necessary, multiple processors and / or multiple buses can be used together with multiple memories and multiple memories. Similarly, multiple computer devices can be connected, and each device provides some necessary operations (for example, as a server array, a group of blade servers, or a multi-processor system). Figure 3 A processor 10 is taken as an example.

[0056] The processor 10 may be a central processing unit, a network processor or a combination thereof. The processor 10 may further include a hardware chip. The hardware chip may be a dedicated integrated circuit, a programmable logic device or a combination thereof. The programmable logic device may be a complex programmable logic device, a field programmable gate array, a general purpose array logic or any combination thereof.

[0057] The memory 20 stores instructions executable by at least one processor 10, so that at least one processor 10 executes the method shown in the above embodiment.

[0058] The memory 20 may include a program storage area and a data storage area, wherein the program storage area may store an operating system, an application required for at least one function; the data storage area may store data created by the use of a computer device based on the presentation of a small program landing page, etc. In addition, the memory 20 may include a high-speed random access memory, and may also include a non-transient memory, such as at least one disk storage device, a flash memory device, or other non-transient solid-state storage device. In some optional embodiments, the memory 20 may optionally include a memory remotely arranged relative to the processor 10, and these remote memories may be connected to the computer device via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0059] The memory 20 may include a volatile memory, such as a random access memory; the memory may also include a non-volatile memory, such as a flash memory, a hard disk or a solid state drive; the memory 20 may also include a combination of the above types of memory.

[0060] The computer device further comprises a communication interface 30 for the computer device to communicate with other devices or a communication network.

[0061] The embodiment of the present invention also provides a computer-readable storage medium. The method according to the embodiment of the present invention can be implemented in hardware, firmware, or can be implemented as a computer code that can be recorded in a storage medium, or can be implemented as a computer code that is originally stored in a remote storage medium or a non-temporary machine-readable storage medium and will be stored in a local storage medium through a network download, so that the method described herein can be stored in such software processing on a storage medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware. Among them, the storage medium can be a magnetic disk, an optical disk, a read-only storage memory, a random access memory, a flash memory, a hard disk or a solid-state hard disk, etc.; further, the storage medium can also include a combination of the above types of memories. It can be understood that a computer, a processor, a microprocessor controller, or programmable hardware includes a storage component that can store or receive software or computer code. When the software or computer code is accessed and executed by a computer, a processor, or hardware, the method shown in the above embodiment is implemented.

[0062] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A method for position-free control of a permanent magnet motor in full speed range, characterized in that: include: Acquiring a speed feedback value of the motor in a rotor coordinate system, wherein the speed feedback value is estimated by an observer; Based on the speed feedback value in the rotor coordinate system and the speed command in the virtual coordinate system, a speed loop control is established by using IF control to rotate the motor; When the speed feedback value cannot track the speed command, based on the speed command, the speed loop is controlled to output a constant saturation upper limit of the current command to the current loop to form a constant current command; when the speed feedback value can track the speed command, based on the speed feedback value and the speed command, the speed loop is controlled to output a current command to the current loop; When the virtual coordinate system does not coincide with the rotor coordinate system, the current loop adopts a coordinate transformation angle obtained by integrating the speed command value, and outputs a voltage reference value based on the current command constant saturation upper limit or the current command; when the virtual coordinate system coincides with the rotor coordinate system, the current loop adopts a coordinate transformation angle estimated by the observer, and outputs a voltage reference value based on the speed feedback value; A switching sequence of a converter of the motor is obtained based on the voltage reference value, and the switching sequence is used to control the on and off of power devices of the converter.

2. The method for position-free control of a permanent magnet motor in full speed range according to claim 1, characterized in that: The process of obtaining the speed feedback value of the motor includes: Collecting three-phase current of the converter of the motor; Performing Clarke transformation on the three-phase current to obtain the current in the αβ coordinate system; Based on the current in the virtual coordinate system, a speed feedback value is calculated using an adaptive synovial observer.

3. The method for position-free control of a permanent magnet motor in full speed range according to claim 1, characterized in that: The process of establishing a speed loop using IF control includes: When the speed feedback value cannot track the speed command, PI adjustment is performed on the speed command to obtain the q-axis current; Based on the q-axis current and the speed command, the IF control is used to obtain the current command steady-state saturation upper limit.

4. The method for position-free control of a permanent magnet motor in full speed range according to claim 1, characterized in that: The process of establishing a speed loop using IF control includes: When the speed feedback value can track the speed command, a PI adjustment is performed on the difference between the speed feedback value and the speed command to obtain a q-axis current; Based on the q-axis current and the rotation speed command, a current command is obtained by using IF control.

5. The method for position-free control of a permanent magnet motor in full speed range according to claim 1, characterized in that: Based on the voltage reference value, a switching sequence of the converter is obtained by using space vector modulation.

6. A permanent magnet motor full speed range position-free control device, characterized in that: include: A speed observer, which is used to obtain a speed feedback value of the motor in a rotor coordinate system, wherein the speed feedback value is estimated by the observer; A speed loop, which is used to determine whether the speed feedback value can track the speed command; when the speed feedback value cannot track the speed command, based on the speed command, the speed loop outputs a constant saturation upper limit of the current command to the current loop; when the speed feedback value can track the speed command, based on the speed feedback value and the speed command, the speed loop outputs a current command to the current loop; A current loop, which is used for outputting a voltage reference value based on the constant saturation upper limit of the current command or the rotor angle command when the virtual coordinate system does not coincide with the rotor coordinate system; and outputting a voltage reference value based on the speed feedback value when the virtual coordinate system coincides with the rotor coordinate system; A modulation module, which is used to obtain a switching sequence of a converter of the motor based on the voltage reference value, and the switching sequence is used to control the on and off of a power device of the converter; The switching module is used to transmit the speed feedback value to the current loop when the virtual coordinate system coincides with the rotor coordinate system; when the virtual coordinate system does not coincide with the rotor coordinate system, transmit the current command constant saturation upper limit or the current command to the current loop.

7. The permanent magnet motor full speed range position-free control device according to claim 6, characterized in that: The speed observer comprises: A Clarke converter is used to collect the three-phase current of the converter of the motor; perform Clarke transformation on the three-phase current to obtain the current in the αβ coordinate system; The adaptive synovial observer is used to calculate the rotation speed feedback value based on the current in the virtual coordinate system.

8. The permanent magnet motor full speed range position-free control device according to claim 6, characterized in that: The speed loop comprises: A subtractor, used for subtracting the speed feedback value from the speed command; A PI regulator, which is used to perform PI regulation on the speed command to obtain the q-axis current when the speed feedback value cannot track the speed command; when the speed feedback value can track the speed command, perform PI regulation on the difference between the speed feedback value and the speed command to obtain the q-axis current; The IF control module is used to obtain a current command steady-state saturation upper limit or a current command based on the q-axis current and the speed command.

9. A computer device, characterized in that: include: A memory and a processor, wherein the memory and the processor are communicatively connected to each other, the memory stores computer instructions, and the processor executes any one of the permanent magnet motor full-speed range position-free control methods of claims 1 to 5 by executing the computer instructions.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a computer to execute the permanent magnet motor full-speed range position-free control method according to any one of claims 1 to 5.

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