Compressor rotor position determination method, controller and air conditioner

Abstract

The invention discloses a rotor position determining method of a compressor, a controller and an air conditioner, and belongs to the technical field related to compressors, and the rotor position determining method of the compressor comprises the steps that phase current of a motor in the compressor is obtained, coordinate transformation is conducted on the phase current, and coordinate system current is obtained; constructing a position observer according to the coordinate system current, and obtaining back electromotive force information of the motor through the position observer; the filter is used for filtering the back electromotive force information, back electromotive force harmonic waves caused by compressor load torque fluctuation can be filtered out, rotor position information can be obtained through the filtered back electromotive force information, and the rotor position observation precision is effectively improved. And the motor of the compressor is controlled based on the filtered rotor position information, and the control performance of the driving system can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of compressors, and in particular to a method for determining a rotor position of a compressor, a controller and an air conditioner. Background Art

[0002] Currently, variable frequency air conditioners mostly use three-phase DC motors as compressor drive motors. The AC power needs to be converted into DC power through a rectifier, and a three-phase AC voltage is generated through an inverter to drive the three-phase DC motor.

[0003] In the related art, during the operation of the compressor drive system, the rotor position of the compressor is observed by using a rotor position observer. However, during the actual operation of the compressor, due to the influence of load torque disturbance, the actual operating current waveform of the compressor contains obvious harmonics, which will have a negative impact on the observation accuracy of the rotor position observer and reduce the control performance of the drive system. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention proposes a method for determining the rotor position of a compressor, which can eliminate the observed back electromotive force harmonics, improve the rotor position observation accuracy, and help improve the control performance of the drive system.

[0005] The present invention also provides the controller, air conditioner and computer-readable storage medium applicable to the above-mentioned controller.

[0006] According to the first aspect of the present invention, a method for determining the rotor position of a compressor includes: acquiring the phase current of the motor in the compressor, and performing coordinate transformation on the phase current to obtain the coordinate system current; constructing a position observer based on the coordinate system current, and obtaining the back electromotive force information of the motor through the position observer; filtering the back electromotive force information with a filter to filter out the back electromotive force harmonics; and calculating the rotor position information based on the filtered back electromotive force information.

[0007] The method for determining the rotor position of a compressor according to an embodiment of the present invention has at least the following beneficial effects: When the compressor is working, the phase current of the motor in the compressor is obtained, and the coordinate system current is obtained after the phase current is transformed. A position observer is constructed according to the coordinate system current, and the position observer is used to observe the back-EMF information of the motor. The back-EMF information is then filtered using a filter, which can filter out the back-EMF harmonics caused by the load torque fluctuation of the compressor. The rotor position information can be obtained through the filtered back-EMF information, which effectively improves the rotor position observation accuracy. The motor of the compressor is controlled based on the filtered rotor position information, which can improve the control performance of the drive system.

[0008] According to some embodiments of the present invention, the coordinate system current includes an α-axis current component and a β-axis current component in the coordinate system, and acquiring the back electromotive force information of the motor through the position observer includes: performing gain processing on the α-axis current component and the β-axis current component; The back electromotive force information is obtained according to the α-axis current component and the β-axis current component after the position observer observes the gain, and the back electromotive force information includes the observed values ​​of the α-axis back electromotive force component and the β-axis back electromotive force component.

[0009] According to some embodiments of the present invention, the filter is a cross-decoupling filter, and the filtering process of the back electromotive force information by using the filter includes: The observed values ​​of the α-axis back electromotive force component and the β-axis back electromotive force component are filtered according to the cross-decoupling filter to obtain the filtered α-axis back electromotive force component and the β-axis back electromotive force component.

[0010] According to some embodiments of the present invention, filtering the observed values ​​of the α-axis back-electromotive force component and the β-axis back-electromotive force component according to the cross-decoupling filter includes: Calculating the observed values ​​of the α-axis back-electromotive force component and the β-axis back-electromotive force component based on the first compensation algorithm of the cross-decoupling filter to obtain a first compensation component, wherein the first compensation component and the first compensation algorithm form a closed-loop regulation; Calculating the observed values ​​of the α-axis back-electromotive force component and the β-axis back-electromotive force component based on the second compensation algorithm of the cross-decoupling filter to obtain a second compensation component, wherein the second compensation component and the second compensation algorithm form a closed-loop regulation; According to the filtering algorithm of the cross-decoupling filter, the first compensation component and the second compensation component, the filtered α-axis back-electromotive force component and the β-axis back-electromotive force component are calculated; Wherein, the filtering algorithm is: ; The first compensation algorithm is: ; The second compensation algorithm is: , represents the damping ratio, s represents a complex variable, j represents an imaginary unit, P represents the number of pole pairs of the motor, represents the observed value of the rotational speed of the rotor.

[0011] According to some embodiments of the present invention, the rotor position determination method further includes: An inverse tangent function is used to perform an inverse tangent operation on the α-axis back electromotive force component and the β-axis back electromotive force component to obtain the angle and rotation speed of the rotor to determine the rotor position information.

[0012] According to some embodiments of the present invention, constructing a position observer according to the coordinate system current includes: According to the state equation of the α-axis current component and the β-axis current component with the stator current of the motor as a variable, the state equation is: ,in, , represents the α-axis and β-axis observation values ​​of the stator current of the motor, R s represents the stator resistance of the motor, ω e represents the rotation speed of the rotor, L d , L q represents the stator d-axis and q-axis inductance of the motor, , is the current component of the α-axis and β-axis in the coordinate system, u α 、u β are the voltage components of the α-axis and β-axis in the coordinate system, , are the back electromotive force components of the α-axis and β-axis in the coordinate system; The full-order state equation of the motor is obtained by combining the relationship between the rate of change of the extended back electromotive force and the extended back electromotive force with the state equation. The relationship between the rate of change of the extended back electromotive force and the extended back electromotive force is: ,in, , represents the estimated value of the α-axis and β-axis back EMF components, represents the observed value of the rotor’s angular velocity; The full-order state equation is: , in, represents the estimated value of current, represents the estimated value of back EMF, , , , , .

[0013] The position observer is constructed according to the full-order state equation.

[0014] According to some embodiments of the present invention, constructing a position observer according to the coordinate system current further includes: The sliding mode function is determined according to the observed error value and the estimated value of the stator current, and the sliding mode function is: ,in, represents the α-axis and β-axis observation error values ​​of the stator current, , Representing the estimated values ​​of the α-axis and β-axis of the stator current; The relationship between the rate of change of the extended back electromotive force and the extended back electromotive force is combined with the state equation to obtain the full-order state equation of the motor, including: The full-order state equation is obtained by combining the relationship, the state equation and the sliding mode function.

[0015] According to some embodiments of the present invention, obtaining the back electromotive force information according to the α-axis current component and the β-axis current component after observing the gain of the position observer includes: Inputting the α-axis current component and the β-axis current component into the position observer after passing through a feedback gain matrix; The α-axis current component and the β-axis current component are processed by the position observer to obtain the observed values ​​of the α-axis back electromotive force component and the β-axis back electromotive force component. The formula of the position observer is: , in, , , , , , , represents the observed value of the current, represents the observed value of the back EMF, , Indicates the observed values ​​of the α-axis and β-axis back EMF components.

[0016] According to some embodiments of the present invention, the acquiring the phase current of the motor in the compressor and transforming the phase current includes: Sampling two-phase currents of the motor to obtain the phase currents; Clarke transformation is performed on the phase current to obtain the α-axis current component and the β-axis current component in a two-phase stationary coordinate system.

[0017] According to an embodiment of the second aspect of the present invention, a controller includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the method for determining the rotor position of the compressor as described in the embodiment of the first aspect above is implemented.

[0018] An air conditioner according to a third aspect of the present invention comprises a compressor and the controller described in the second aspect of the present invention.

[0019] According to a computer-readable storage medium of an embodiment of the fourth aspect of the present invention, computer-executable instructions are stored, and the computer-executable instructions are used to execute the method for determining the rotor position of the compressor as described in the embodiment of the first aspect.

[0020] Other features and advantages of the present invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which: Figure 1 is a control principle block diagram of a compressor motor drive system according to an embodiment of the present invention; Figure 2 is a flowchart of steps of a method for determining a rotor position of a compressor according to an embodiment of the present invention; Figure 3 is a flowchart of steps for obtaining back-EMF information of a motor through a position observer in one embodiment of the present invention; Figure 4 is a flowchart of the steps of the filtering process of the cross-decoupling filter in one embodiment of the present invention; Figure 5 It is a schematic diagram of the principle of using a cross-decoupling filter to eliminate back electromotive force harmonics caused by load torque fluctuations in one embodiment of the present invention; Figure 6 is a flowchart of steps for constructing a position observer according to a coordinate system current in one embodiment of the present invention; Figure 7 is a flowchart of steps for calculating rotor position information according to filtered back electromotive force information in one embodiment of the present invention; Figure 8 is a principle block diagram of a full-order position observer based on an extended back electromotive force model in one embodiment of the present invention; Fig. 9 is a schematic diagram of a back electromotive force waveform before passing through a cross-decoupling filter in a rotor position determination method according to an embodiment of the present invention; Fig.10 1 is a schematic diagram of a back electromotive force waveform after passing through a cross-decoupling filter in a rotor position determination method according to an embodiment of the present invention. DETAILED DESCRIPTION

[0022] In order to more clearly understand the above-mentioned purpose, features and advantages of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0023] In the description of the present invention, examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0024] In the description of the present invention, the various steps described in the method implementation can be performed in different orders and / or in parallel. In addition, the method implementation may include additional steps and / or omit the steps shown. The scope of the present disclosure is not limited in this respect.

[0025] In the description of the present invention, if there is a description of first and second, it is only for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0026] In the description of the present invention, it should be noted that the terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention in combination with the specific content of the technical solution.

[0027] The technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described below are part of the embodiments of the present invention, not all of the embodiments. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited by the specific embodiments disclosed below.

[0028] At present, variable frequency air conditioners mostly use three-phase DC motors as the driving motors of compressors. It is necessary to convert the mains electricity into DC through a rectifier, and generate three-phase AC voltage through an inverter to drive the three-phase DC motor. In the related art, during the operation of the compressor drive system, the rotor position of the compressor is observed by using a rotor position observer.

[0029] In the existing schemes, the motor phase current information is sampled, and the corresponding motor current in the stationary and rotating coordinate systems is obtained after coordinate transformation. The rotor position observer with a feedback loop is constructed based on the motor mathematical model. However, in the actual operation of the compressor, due to the influence of load torque disturbance, the actual operating current waveform of the compressor contains obvious harmonics, which will have a negative impact on the observation accuracy of the rotor position observer and reduce the control performance of the drive system.

[0030] In order to solve the above problems, an embodiment of the present invention provides a method for determining the rotor position of a compressor, wherein the compressor is suitable for a variable frequency air conditioner. Figures 1 to 5 A method for determining the rotor position of a compressor according to an embodiment of the present invention will be described.

[0031] Reference Figure 1 As shown, Figure 1 The control principle block diagram of the compressor drive motor in the embodiment of the present invention is shown. The drive motor is specifically a permanent magnet synchronous motor. By sampling the motor phase current information, the two-phase current of the motor stator is obtained, including the current and current Specifically, the sensor can be used to sample the two-phase current of the motor stator; the obtained phase current is transformed by Clark to obtain the current of the two-phase stationary coordinates and ,in is the α-axis current component, is the β-axis current component. The rotor position of the motor is observed by the position observer. The rotor position includes the rotor angular position and the rotor speed. and After Park transformation, the current in the two-phase rotating coordinate system is obtained and , set the motor speed ω * Compared with the speed observed by the position observer, the output quadrature axis current is given by the speed PI regulator. , according to the direct axis current given as = 0, compare the direct axis and quadrature axis currents with the actual detection values and Compared with each other, they are then passed through the current PI regulator to output the direct axis voltage value and the quadrature axis voltage value , and then through Park inverse transformation, the voltage value under the two-phase stationary coordinate system is obtained and ; According to the voltage value and Perform space vector modulation to generate PWM signals, which are then output to the inverter. The inverter is used to control the operation of the permanent magnet synchronous motor to achieve precise control of the motor.

[0032] It should be noted that the torque of the motor depends on and The size of and The torque of the motor can be controlled. Since a certain speed and torque correspond to a certain and By controlling these two currents, the actual and Tracking instruction values and , thereby achieving the control of motor torque and speed.

[0033] For permanent magnet synchronous motors, by detecting the three-phase AC current of the armature winding , and , which is the stator current, and then the current in the rotating two-phase dq coordinates is obtained by coordinate transformation and In this process, the position information of the motor rotor is needed. The present invention detects the input voltage and current of the motor, estimates the back electromotive force information using a position observer, and obtains the rotor position information through calculation.

[0034] Reference Figure 2 As shown, the method for determining the rotor position of a compressor provided by an embodiment of the present invention includes but is not limited to the following steps: Step S100, obtaining the phase current of the motor in the compressor, and performing coordinate transformation on the phase current to obtain the coordinate system current.

[0035] Specifically, the three-phase current of the motor is sampled, and the sampled phase current is transformed by Clark to obtain the current in the two-phase stationary coordinate. and For example, the Clark transform is: , According to the above transformation formula, the current and .

[0036] It should be noted that the rotor position determination method of the embodiment is aimed at controlling the motor in the compressor, and the compressor needs to be in operation before executing the above step S100, that is, when the compressor starts to run, the motor starts, and then the action of obtaining the phase current of the motor is executed.

[0037] In addition, refer to Figure 1 As shown, Park transform is , According to the above Park transformation formula, the current can be obtained and .

[0038] Step S200: construct a position observer according to the coordinate system current, and obtain back electromotive force information of the motor through the position observer.

[0039] Reference Figure 1 As shown in the figure, on the basis of the overall control block diagram of the motor, a position observer is added, and the position observer is combined with the original control scheme.

[0040] Specifically, the motor current in the corresponding stationary coordinate system can be obtained through the above step S100, and then a position observer with a feedback loop is constructed through the motor mathematical model, wherein the motor mathematical model is constructed based on the motor current in the stationary coordinate system, and specifically the position observer is established with the stator current as the state variable. In the embodiment, the current and As the state variable, a position observer based on the back-EMF model is constructed. It should be noted that the back-EMF information is the observation value of the position observer, specifically including the observation value of the α-axis back-EMF component and the observation value of the β-axis back-EMF component. The α-axis and β-axis back-EMF components can be understood as the back-EMF in the coordinate system.

[0041] Step S300: Filter the back electromotive force information using a filter to filter out back electromotive force harmonics.

[0042] Reference Figure 1 As shown, based on the overall control block diagram of the motor, a filter is added. After the position observer observes the back electromotive force information of the motor, the back electromotive force information is filtered through the filter.

[0043] Specifically, considering that the periodic load torque of a single-rotor compressor will cause back-EMF harmonics, which will have a negative impact on the observation accuracy of the rotor position observer, after the embodiment of the present invention obtains the back-EMF information through position observer observation, it is necessary to filter the back-EMF information through a filter, specifically, to filter the back-EMF observation value and the estimated speed value, so as to eliminate the back-EMF harmonics caused by load disturbances. The back-EMF harmonics are effectively suppressed, and the rotor position observation accuracy is improved.

[0044] It should be noted that the filter in the embodiment may be a cross-decoupling filter or other filters capable of filtering out back electromotive force harmonics.

[0045] Step S400, calculating and obtaining rotor position information according to the filtered back electromotive force information.

[0046] It can be understood that the rotor position information can be calculated through the filtered back-EMF information. The rotor position information includes the rotor angular position and the rotor speed. At this time, the influence of the load torque disturbance can be effectively reduced, and the accuracy of the rotor position information can be higher. In this way, the compressor motor can be controlled based on the filtered rotor position information to improve the control performance of the drive system.

[0047] Reference Figure 3 As shown, Figure 3 The specific steps of obtaining the back electromotive force information of the motor through the position observer in the embodiment of the present invention are shown, including: Step S210, performing gain processing on the α-axis current component and the β-axis current component; Step S220 , obtaining back electromotive force information based on the α-axis current component and the β-axis current component after observing the gain of the position observer, wherein the back electromotive force information includes the observed values ​​of the α-axis back electromotive force component and the β-axis back electromotive force component.

[0048] Specifically, the α-axis current component and the β-axis current component in the embodiment are respectively expressed as and , can be amplified by gain processing and times, and then add the gain and As the input parameter of the position observer, the observation value of the α-axis back EMF component and the observation value of the β-axis back EMF component can be obtained through the position observer. The observation value of the α-axis back EMF component is , the observed value of the β-axis back EMF component is .

[0049] The present invention is described by taking a cross-decoupling filter as a specific example. The specific steps of using the filter to filter the back electromotive force information include: Step S310 , filtering the observed values ​​of the α-axis back electromotive force component and the β-axis back electromotive force component according to the cross-decoupling filter to obtain filtered α-axis back electromotive force component and β-axis back electromotive force component.

[0050] Reference Figure 1 As shown, it can be understood that the position observer obtains and Then it is input into the cross-decoupling filter for filtering, and after filtering, it is obtained and ,in is the α-axis back EMF component, is the β-axis back electromotive force component. The cross-decoupling filter can eliminate the back electromotive force harmonics caused by load disturbance. The cross-decoupling filter has the characteristics of simple structure and good filtering effect, and is suitable for filtering orthogonal signals.

[0051] Reference Figure 4 As shown, Figure 4 The cross-decoupling filter pair in the embodiment of the present invention is shown. and The specific steps of filtering processing include: Step S311 , based on the first compensation algorithm of the cross-decoupling filter, the observed values ​​of the α-axis back-EMF component and the β-axis back-EMF component are calculated to obtain a first compensation component, and the first compensation component and the first compensation algorithm form a closed-loop regulation.

[0052] Combination Figure 5 It is understandable that Figure 5 The schematic diagram shows the principle of using a cross-decoupling filter to eliminate the back electromotive force harmonics caused by load torque fluctuations. The first compensation algorithm is ,in, represents the damping ratio, s represents a complex variable, j represents an imaginary unit, P represents the number of pole pairs of the motor, represents the observed value of the rotor speed; the first compensation component is , Including the α-axis back EMF compensation component and the β-axis back EMF compensation component ,also, Represents the α-axis and β-axis back EMF components, that is, Figure 1 As shown in and , by taking the first compensation component Feedback, the first compensation component and the back EMF component After comparison, the first compensation component A closed-loop regulation is formed with the first compensation algorithm to maintain the stability of the first compensation component.

[0053] Step S312, based on the second compensation algorithm of the cross-decoupling filter, the observed values ​​of the α-axis back-EMF component and the β-axis back-EMF component are calculated to obtain a second compensation component, and the second compensation component and the second compensation algorithm form a closed-loop regulation.

[0054] Reference Figure 5 As shown, the second compensation algorithm is: , the second compensation component is , Including the α-axis back EMF compensation component and the β-axis back EMF compensation component , by taking the second compensation component Feedback, the second compensation component and the back EMF component After comparison, the second compensation component A closed-loop regulation is formed with the second compensation algorithm to maintain the stability of the second compensation component.

[0055] Step S313 , calculating and obtaining the filtered α-axis back electromotive force component and β-axis back electromotive force component according to the filtering algorithm of the cross-decoupling filter, the first compensation component and the second compensation component.

[0056] Continue to refer to Figure 5 As shown, the filtering algorithm used is: , the first compensation component and the second compensation component Feedback to the above filtering algorithm, the filtered and ,use Figure 5 The cross-decoupling filter shown can improve the back-EMF observation effect, and can effectively filter out the back-EMF harmonics by analyzing and compensating the back-EMF harmonics caused by the periodic load torque of the single-rotor compressor.

[0057] Reference Fig. 9 and Fig.10 As shown, Fig. 9 The back EMF waveform before cross-decoupling filtering is shown. At this time, the total harmonic distortion THD = 11.13%. Due to the influence of load torque disturbance, the voltage waveform contains obvious harmonics, which will have a negative impact on the observation accuracy of the rotor position observer; Fig.10 The back-EMF waveform after cross-decoupling filtering is shown. At this time, the total harmonic distortion THD=2.28%. It can be seen that after the cross-decoupling filtering link, the back-EMF harmonics caused by load torque fluctuations are effectively suppressed, and the rotor position observation accuracy is improved.

[0058] Reference Figure 6 As shown, the specific steps of constructing a position observer according to the coordinate system current in the embodiment of the present invention include: Step S230, a state equation is generated based on the α-axis current component and the β-axis current component with the stator current of the motor as a variable. The state equation is: ,in, , Represents the α-axis and β-axis observation values ​​of the motor’s stator current, R s Represents the stator resistance of the motor, ω e Indicates the rotor speed, L d , L qIndicates the stator d-axis and q-axis inductance of the motor, , is the current component of the α-axis and β-axis in the coordinate system, u α 、u β are the voltage components of the α-axis and β-axis in the coordinate system, , are the back electromotive force components of the α-axis and β-axis in the coordinate system.

[0059] It should be noted that when establishing the state equation, the voltage equation in the two-phase stationary scale of the α-axis and β-axis is first constructed, and then the above voltage equation is rewritten into a state equation with the stator current as a variable, that is, the state equation of the above embodiment is obtained.

[0060] Specifically, the voltage equation is: , where p represents the differential operator, , It represents the extended back electromotive force component under the α-axis and β-axis coordinate system, , , represents the extended back EMF.

[0061] It is understandable that considering that the physical quantity that can be directly measured in the control system is the stator current of the motor, the sliding surface Selected to be on the stator current trajectory.

[0062] Specifically, in step S240, a sliding mode function is determined according to the observed error value and the estimated value of the stator current. The sliding mode function is: , where the parameter with the superscript “~” is the error value, that is, the difference between the observed value and the actual value of the variable. Specifically, Represents the α-axis and β-axis observation error values ​​of the stator current, , Indicates the estimated values ​​of the α-axis and β-axis of the stator current.

[0063] Normally, since the mechanical time constant of the control system is much larger than the electromagnetic time constant, the rotor angular velocity is considered to be constant during the PWM control cycle. At this time, the relationship between the rate of change of the extended back EMF and the extended back EMF is as follows: ,in, , represents the estimated value of the α-axis and β-axis back EMF components, represents the observed value of the rotor’s angular velocity; Step S250, according to the relationship between the rate of change of the extended back electromotive force and the extended back electromotive force, the state equation and the sliding mode function are combined to obtain the full-order state equation of the motor, and the full-order state equation is: ,in, represents the estimated value of the current, represents the estimated value of back EMF, , , , , , T is a constant.

[0064] Step S260: construct a position observer according to the full-order state equation.

[0065] It can be understood that the position observer constructed using the full-order state equation is also called a full-order position observer. The full-order position observer is based on the extended back electromotive force model. By observing the back electromotive force using the full-order position observer, it is possible to obtain and , and then a cross-decoupling filter is used to eliminate the back EMF harmonics caused by the compressor load torque fluctuation.

[0066] Specifically, the full-order position observer constructed according to the above full-order equation is: , in, , , , , , , represents the observed value of the current, represents the observed value of the back EMF, , represents the observed values ​​of the α-axis and β-axis back EMF components, K is the feedback gain matrix, represents the estimated value of current, represents the estimated value of back EMF, k and m are the sliding mode observation gains obtained after Lyapunov exponential stability analysis.

[0067] In the embodiment, the back electromotive force information is obtained according to the α-axis current component and the β-axis current component after the position observer observes the gain, and the specific steps include: Step S270, inputting the α-axis current component and the β-axis current component into a full-order position observer after passing through a feedback gain matrix; Step S280: Process the α-axis current component and the β-axis current component through a full-order position observer to obtain observation values ​​of the α-axis back electromotive force component and the β-axis back electromotive force component.

[0068] It can be understood that using the above-mentioned full-order position observer ,Will and As a variable, and After the feedback gain matrix is ​​passed through the full-order position observer, it is calculated and .

[0069] Reference Figure 8 As shown, Figure 8 The principle block diagram of the full-order position observer based on the extended back-EMF model is as follows: and Sure ,according to and Sure , then according to and The α-axis current component and the β-axis current component are determined and used as input parameters of the position observer after passing through the feedback gain matrix.

[0070] Combination Figure 1 It can be understood that the constructed position observer can be observed and After that, it is input into the cross-decoupling filter for filtering, and after filtering, it is obtained and ,The use of cross-decoupling filter can eliminate the back electromotive force harmonics caused by load disturbance, ,compensate for the negative impact of the compressor load torque on the ,rotor position observation, which can effectively improve the accuracy of the ,rotor position observation, and is simple to implement and has good robustness.

[0071] Reference Figure 7 As shown, the step of calculating the rotor position information according to the filtered back electromotive force information in the embodiment of the present invention specifically includes: Step S410, using an inverse tangent function to perform an inverse tangent operation on the α-axis back electromotive force component and the β-axis back electromotive force component to obtain the angle and speed of the rotor to determine the rotor position information.

[0072] It can be understood that the inverse function of the tangent function y=tanx in the open interval (x∈(-π / 2,π / 2)) is denoted as y=arctanx or y=tan-1x, which is called the inverse tangent function. The inverse tangent function can be used for phase compensation. Since the filter has a phase delay characteristic, the calculated rotor position has errors, so the estimated value of the rotor position needs to be phase compensated.

[0073] Reference Figure 1As shown, it can be understood that when the permanent magnet synchronous motor is used in the compressor, when the closed loop stage is not adopted, the rotor position information is not obtained by observing the back electromotive force based on the position observer and filtering by the cross decoupling filter. After entering the closed loop and running stably, the motor is given a speed ω * The rotor speed is compared with the rotor speed observed by the position observer and then output after passing through the speed PI regulator. ,Bundle and The actual detection value and Compare and pass through the current PI regulator respectively, and output and , and then through Park's inverse transformation, we get and ; According to the voltage value and Perform space vector modulation to generate PWM signals, which are then output to the inverter. The inverter is used to control the operation of the permanent magnet synchronous motor to achieve precise control of the motor.

[0074] It can be understood that the control method in the non-closed-loop stage does not analyze and compensate for the back-electromotive force harmonics caused by the periodic load torque of the single-rotor compressor, which is a traditional control method. Compared with the traditional control method, the embodiment of the present invention compensates for the negative impact of the compressor load torque on the rotor position observation by analyzing the harmonic information caused by the load torque disturbance. Specifically, the actual current signal of the motor is collected, and the back-electromotive force is observed after the coordinate transformation. A cross-decoupling filter is used to eliminate the back-electromotive force harmonics caused by the load disturbance. The cross-decoupling filter has the characteristics of simple structure and good filtering effect, which can effectively improve the rotor position observation accuracy, simple implementation, good robustness, and improve the control performance of the drive system.

[0075] In addition, an embodiment of the present invention further provides a controller, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, a method for determining the rotor position of a compressor as in the above embodiment is implemented.

[0076] Take the control processor and memory in the controller as an example that can be connected through a bus. The memory, as a non-transient computer-readable storage medium, can be used to store non-transient software programs and non-transient computer executable programs. In addition, the memory may include a high-speed random access memory, and may also include a non-transient memory, such as at least one disk memory, a flash memory device, or other non-transient solid-state storage device. In some embodiments, the memory may optionally include a memory remotely arranged relative to the control processor, and these remote memories may be connected to the controller 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.

[0077] The non-transient software program and instructions required to implement the compressor rotor position determination method of the above embodiment are stored in the memory. When executed by the processor, the compressor rotor position determination method of the above embodiment is executed, for example, the above described method is executed. Figure 2 Steps S100 to S400 of the method, Figure 3 Steps S210 to S220 of the method, Figure 4 Steps S311 to S313 of the method, Figure 6 Steps S230 to S260 of the method and Figure 7 Method step S410 in .

[0078] The device embodiments described above are merely illustrative, and the units described as separate components may or may not be physically separated, that is, they may be located in one place or distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0079] In addition, the method for determining the rotor position of a compressor in an embodiment of the present invention may be a method for determining the rotor position of a double-door compressor, a method for determining the rotor position of a single-door compressor, etc., without specific limitation. The method for determining the rotor position of a compressor includes the controller of the above embodiment, and the controller executes the control method of the method for determining the rotor position of a compressor in the above embodiment.

[0080] In addition, an embodiment of the present invention further provides a computer-readable storage medium, which stores computer-executable instructions, and the computer-executable instructions are used to execute the above-mentioned control method, for example, being executed by a processor, so that the above-mentioned one or more processors can execute the control method in the above-mentioned method embodiment, for example, executing the above-mentioned Figure 2 Steps S100 to S400 of the method, Figure 3 Steps S210 to S220 of the method, Figure 4 Steps S311 to S313 of the method, Figure 6 Steps S230 to S260 of the method and Figure 7 Method step S410 in .

[0081] The device embodiments described above are merely illustrative, and the units described as separate components may or may not be physically separated, that is, they may be located in one place or distributed on multiple network nodes. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0082] It will be appreciated by those skilled in the art that all or some of the steps and systems in the disclosed method above may be implemented as software, firmware, hardware and appropriate combinations thereof. Some physical components or all physical components may be implemented as software executed by a processor, such as a central processing unit, a digital signal processor or a microprocessor, or may be implemented as hardware, or may be implemented as an integrated circuit, such as an application specific integrated circuit. Such software may be distributed on a computer-readable medium, which may include a computer-readable storage medium (or a non-transitory medium) and a communication medium (or a temporary medium). As known to those skilled in the art, the term computer-readable storage medium includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information (such as computer-readable instructions, data structures, program modules or other data). Computer-readable storage media include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technologies, CD-ROM, digital versatile disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tapes, disk storage or other magnetic storage devices, or any other medium that may be used to store desired information and may be accessed by a computer. Furthermore, it is well known to those skilled in the art that communication media typically embodies computer readable instructions, data structures, program modules, or other data in a modulated data signal such as a carrier wave or other transport mechanism, and may include any information delivery media.

[0083] The embodiments of the present invention are described in detail above with reference to the accompanying drawings, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge scope of ordinary technicians in the relevant technical field without departing from the purpose of the present invention.

Claims

1. A method for determining a rotor position of a compressor, characterized in that: include: Acquire the phase current of the motor in the compressor, and perform coordinate transformation on the phase current to obtain the coordinate system current; Constructing a position observer according to the coordinate system current, and acquiring back electromotive force information of the motor through the position observer; Using a filter to filter the back electromotive force information to filter out back electromotive force harmonics; The rotor position information is calculated based on the filtered back electromotive force information.

2. The method for determining the rotor position of a compressor according to claim 1, characterized in that: The coordinate system current includes an α-axis current component and a β-axis current component in the coordinate system, and the back electromotive force information of the motor is obtained by the position observer, including: performing gain processing on the α-axis current component and the β-axis current component; The back electromotive force information is obtained according to the α-axis current component and the β-axis current component after the position observer observes the gain, and the back electromotive force information includes the observed values ​​of the α-axis back electromotive force component and the β-axis back electromotive force component.

3. The method for determining the rotor position of a compressor according to claim 2, characterized in that: The filter is a cross-decoupling filter, and the filter is used to filter the back electromotive force information, including: The observed values ​​of the α-axis back electromotive force component and the β-axis back electromotive force component are filtered according to the cross-decoupling filter to obtain the filtered α-axis back electromotive force component and the β-axis back electromotive force component.

4. The method for determining the rotor position of a compressor according to claim 3, characterized in that: The filtering process of the observed values ​​of the α-axis back electromotive force component and the β-axis back electromotive force component according to the cross-decoupling filter comprises: Calculating the observed values ​​of the α-axis back-electromotive force component and the β-axis back-electromotive force component based on the first compensation algorithm of the cross-decoupling filter to obtain a first compensation component, wherein the first compensation component and the first compensation algorithm form a closed-loop regulation; Calculating the observed values ​​of the α-axis back-electromotive force component and the β-axis back-electromotive force component based on the second compensation algorithm of the cross-decoupling filter to obtain a second compensation component, wherein the second compensation component and the second compensation algorithm form a closed-loop regulation; According to the filtering algorithm of the cross-decoupling filter, the first compensation component and the second compensation component, the filtered α-axis back-electromotive force component and the β-axis back-electromotive force component are calculated; Wherein, the filtering algorithm is: ; The first compensation algorithm is: ; The second compensation algorithm is: , represents the damping ratio, s represents a complex variable, j represents an imaginary unit, P represents the number of pole pairs of the motor, represents the observed value of the rotational speed of the rotor.

5. The method for determining the rotor position of a compressor according to claim 3, characterized in that: The rotor position determination method further includes: An inverse tangent function is used to perform an inverse tangent operation on the α-axis back electromotive force component and the β-axis back electromotive force component to obtain the angle and rotation speed of the rotor to determine the rotor position information.

6. The method for determining the rotor position of a compressor according to claim 2, characterized in that: The step of constructing a position observer according to the coordinate system current comprises: According to the state equation of the α-axis current component and the β-axis current component with the stator current of the motor as a variable, the state equation is: ,in, , represents the α-axis and β-axis observation values ​​of the stator current of the motor, R s represents the stator resistance of the motor, ω e represents the rotation speed of the rotor, L d , L q represents the stator d-axis and q-axis inductance of the motor, , is the current component of the α-axis and β-axis in the coordinate system, u α 、u β are the voltage components of the α-axis and β-axis in the coordinate system, , are the back electromotive force components of the α-axis and β-axis in the coordinate system; The full-order state equation of the motor is obtained by combining the relationship between the rate of change of the extended back electromotive force and the extended back electromotive force with the state equation. The relationship between the rate of change of the extended back electromotive force and the extended back electromotive force is: ,in, , represents the estimated value of the α-axis and β-axis back EMF components, represents the observed value of the rotor’s angular velocity; The full-order state equation is: ， in, represents the estimated value of the current, represents the estimated value of back EMF, , , , , . The position observer is constructed according to the full-order state equation.

7. The method for determining the rotor position of a compressor according to claim 6, characterized in that: The constructing of the position observer according to the coordinate system current also includes: The sliding mode function is determined according to the observed error value and the estimated value of the stator current, and the sliding mode function is: ,in, represents the α-axis and β-axis observation error values ​​of the stator current, , Representing the estimated values ​​of the α-axis and β-axis of the stator current; The relationship between the rate of change of the extended back electromotive force and the extended back electromotive force is combined with the state equation to obtain the full-order state equation of the motor, including: The full-order state equation is obtained by combining the relationship, the state equation and the sliding mode function.

8. The method for determining the rotor position of a compressor according to claim 2 or 6, characterized in that: The step of obtaining the back electromotive force information according to the α-axis current component and the β-axis current component after observing the gain of the position observer includes: Inputting the α-axis current component and the β-axis current component into the position observer after passing through a feedback gain matrix; The α-axis current component and the β-axis current component are processed by the position observer to obtain the observed values ​​of the α-axis back electromotive force component and the β-axis back electromotive force component. The formula of the position observer is: ， in, , , , , , , represents the observed value of the current, represents the observed value of the back EMF, , Indicates the observed values ​​of the α-axis and β-axis back EMF components.

9. The method for determining the rotor position of a compressor according to claim 1, characterized in that: The step of obtaining the phase current of the motor in the compressor and transforming the phase current includes: Sampling two-phase currents of the motor to obtain the phase currents; Clarke transformation is performed on the phase current to obtain the α-axis current component and the β-axis current component in a two-phase stationary coordinate system.

10. A controller, characterized in that The method comprises a memory, a processor and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the method for determining the rotor position of the compressor according to any one of claims 1 to 9 is implemented.

11. An air conditioner, characterized in that The invention comprises a compressor and the controller as claimed in claim 10.

12. A computer-readable storage medium, characterized in that Computer executable instructions are stored, and the computer executable instructions are used to execute the rotor position determination method of the compressor as claimed in any one of claims 1 to 9.

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