Method and device for determining rotor position during starting of synchronous motor

Abstract

The invention discloses a method and device for determining the position of a rotor when a synchronous motor is started, and the method comprises the steps: firstly, injecting a voltage pulse into an alpha axis or a beta axis, and then determining a stator flux linkage vector calculation value; the stator flux linkage vector calculation value comprises a component calculation value of a stator flux linkage vector in an alpha axis under a static two-phase coordinate system and a component calculation value of the stator flux linkage vector in a beta axis under the static two-phase coordinate system; determining a plurality of stator flux linkage vector estimation values according to the position range of the rotor, wherein the stator flux linkage vector estimation values comprise a component estimation value of a stator flux linkage vector in an alpha axis under a static two-phase coordinate system and a component estimation value of the stator flux linkage vector in a beta axis under the static two-phase coordinate system; and finally, the rotor position is determined based on the plurality of stator flux linkage vector estimated values and the stator flux linkage vector calculated values, so that the identification time of the rotor position when the synchronous motor is started can be shortened, the identification precision of the rotor position is improved, and the starting time of the synchronous motor is shortened.

Description

Technical Field

[0001] The present invention belongs to the technical field of motors, and in particular relates to a method and a device for determining the rotor position when a synchronous motor is started. Background Art

[0002] In order to improve the load starting performance of synchronous motors, synchronous motor drivers are usually equipped with the function of motor initial position identification, that is, before each motor operation, the motor initial position, i.e. rotor position, is identified first, and then the motor is started. The duration of the initial position identification will affect the overall starting time of the motor.

[0003] At present, the conventional rotor position identification methods when the synchronous motor starts are the high-frequency injection method and the voltage pulse method. The high-frequency injection method requires the design of multiple filters to extract the rotor position information contained in the high-frequency response signal, and it also requires a separate magnetic pole identification stage. Therefore, the high-frequency injection method takes hundreds of milliseconds to identify the rotor position, which is relatively long. The voltage pulse method has a short identification time, but the identification accuracy is low. If the identification accuracy of the voltage pulse method is to be improved, multiple voltage pulses need to be added, but the identification time will be increased and the noise in the identification process will be increased.

[0004] Therefore, how to reduce the recognition time of the rotor position when the synchronous motor is started and improve the recognition accuracy of the rotor position is a technical problem to be solved by those skilled in the art. Summary of the invention

[0005] The purpose of the present invention is to solve the technical problem in the prior art that it is impossible to improve the recognition accuracy while reducing the rotor position recognition time when the synchronous motor is started.

[0006] To achieve the above technical objectives, on the one hand, the present invention provides a method for determining the rotor position when a synchronous motor is started, the method comprising:

[0007] After injecting a voltage pulse into the α-axis or β-axis, a calculated value of a stator flux vector is determined, wherein the calculated value of the stator flux vector includes a calculated value of a component of the stator flux vector on the α-axis in a stationary two-phase coordinate system and a calculated value of a component of the stator flux vector on the β-axis in a stationary two-phase coordinate system;

[0008] Determine a plurality of stator flux vector estimation values ​​according to the position range of the rotor, wherein the stator flux vector estimation value includes an α-axis component estimation value of the stator flux vector in a stationary two-phase coordinate system and a β-axis component estimation value of the stator flux vector in a stationary two-phase coordinate system;

[0009] The rotor position is determined based on a plurality of stator flux vector estimation values ​​and the stator flux vector calculation value.

[0010] Further, the determining of a plurality of stator flux vector estimation values ​​according to the position range of the rotor specifically comprises equally dividing a plurality of first rotor positions according to the position range, and determining the stator flux vector estimation value according to the first rotor positions.

[0011] Further, the stator flux vector estimation value is determined according to the first rotor position, and is specifically determined by the following formula:

[0012]

[0013] In the formula, ψ α i (k) is the estimated value of the α-axis component of the stator flux vector in the stationary two-phase coordinate system at the current beat k, ψ β i (k) is the estimated value of the β-axis component of the stator flux vector in the stationary two-phase coordinate system at the current beat k, θ i is the first rotor position, ψ d (k) is the direct axis flux at the current beat k, ψ q (k) is the cross-axis flux at the current beat k.

[0014] Furthermore, the direct-axis flux and the cross-axis flux at the current beat k are specifically determined by the following formula:

[0015] ψ d (k) = i d (k)×L d (i d (k),i q (k))+ψ f (k)

[0016] ψ q (k) = i q (k)×L q (i d (k),i q (k))

[0017] In the formula, i d (k) is the direct axis current at the current beat k, L d is the direct-axis inductance, i q (k) is the quadrature axis current at the current beat k, ψ f (k) is the permanent magnet flux amplitude or rotor excitation flux amplitude at the current beat k, i q (k) is the quadrature axis current at the current beat k, L q is the quadrature-axis inductance, i d (k) is the direct axis current at the current beat k.

[0018] Further, the step of injecting a voltage pulse into the α-axis or β-axis to determine the calculated value of the stator flux vector specifically includes:

[0019] After injecting a voltage pulse into the α-axis or β-axis, simultaneously collecting the stator current vector and the stator voltage vector, the stator current vector includes the component of the stator current vector on the α-axis in the stationary two-phase coordinate system and the component of the stator current vector on the β-axis in the stationary two-phase coordinate system, and the stator voltage vector includes the component of the stator voltage vector on the α-axis in the stationary two-phase coordinate system and the component of the stator voltage vector on the β-axis in the stationary two-phase coordinate system;

[0020] The stator flux vector calculation value is determined based on the stator current vector and the stator voltage vector.

[0021] Furthermore, the calculated value of the stator flux vector is determined specifically by the following formula:

[0022] ψ α (k) = ψ α (k-1)+T s (u α (k-2)-R s i α (k))

[0023] ψ β (k) = ψ β (k-1)+T s (u β (k-2)-R s i β (k))

[0024] In the formula, ψ α (k) is the calculated value of the α-axis component of the stator flux vector in the stationary two-phase coordinate system at the current beat k, ψ β (k) is the calculated value of the β-axis component of the stator flux vector in the stationary two-phase coordinate system at the previous beat of the current beat k, ψ α (k-1) is the calculated value of the α-axis component of the stator flux vector in the stationary two-phase coordinate system at the current beat k, ψ β (k-1) is the calculated value of the β-axis component of the stator flux vector in the stationary two-phase coordinate system at the previous beat of the current beat k, u α (k-2) is the sampling value of the stator voltage vector on the α-axis in the static two-phase coordinate system at the previous two beats of the current beat k, u β (k-2) is the sampling value of the stator voltage vector on the α-axis in the static two-phase coordinate system at the previous two beats of the current beat k, i α (k) is the sampling value of the stator current vector on the α-axis in the stationary two-phase coordinate system at the current beat k, i β(k) is the sampling value of the stator current vector on the β axis in the stationary two-phase coordinate system at the current beat k, R s is the stator resistance.

[0025] Further, the determining the rotor position based on the multiple stator flux vector estimation values ​​and the stator flux vector calculation value specifically includes:

[0026] Determining an error between the calculated value of the stator flux vector and each estimated value of the stator flux vector;

[0027] The first rotor position corresponding to the stator flux vector estimation value with the smallest error is used as the rotor position.

[0028] Furthermore, the method further comprises:

[0029] When a plurality of groups of stator current vectors and stator voltage vectors are collected;

[0030] Determine a first variation between adjacent beats according to a stator flux vector calculation value determined by each group of stator current vectors and stator voltage vectors, and simultaneously determine a second variation between adjacent beats of all stator flux vector estimation values;

[0031] The rotor position is determined based on the first change amount and the second change amount.

[0032] Further, each second variation corresponds to an angle, and determining the rotor position based on the first variation and the second variation specifically includes:

[0033] Determine the error between each first variation and all second variations and use the smallest error as the second error;

[0034] The rotor positions corresponding to all the second errors are summed and averaged to obtain the final rotor position.

[0035] On the other hand, the present invention further provides a device for determining the rotor position when a synchronous motor is started, the device comprising:

[0036] A first determination module is used to determine a stator flux vector calculation value after injecting a voltage pulse into the α-axis or β-axis, wherein the stator flux vector calculation value includes a component calculation value of the stator flux vector in the α-axis in a stationary two-phase coordinate system and a component calculation value of the stator flux vector in the β-axis in a stationary two-phase coordinate system;

[0037] a second determination module, configured to determine a plurality of stator flux vector estimation values ​​according to a rotor position range, wherein the stator flux vector estimation value includes an α-axis component estimation value of the stator flux vector in a stationary two-phase coordinate system and a β-axis component estimation value of the stator flux vector in a stationary two-phase coordinate system;

[0038] The third determination module is used to determine the rotor position based on a plurality of stator flux vector estimation values ​​and the stator flux vector calculation value.

[0039] The present invention provides a method and device for determining the rotor position when a synchronous motor is started. Compared with the prior art, the method first injects a voltage pulse into the α-axis or β-axis to determine a calculated value of a stator flux vector, wherein the calculated value of the stator flux vector includes a calculated value of a component of the stator flux vector on the α-axis in a stationary two-phase coordinate system and a calculated value of a component of the stator flux vector on the β-axis in a stationary two-phase coordinate system; then, multiple stator flux vector estimation values ​​are determined according to the position range of the rotor, wherein the estimated value of the stator flux vector includes an estimated value of a component of the stator flux vector on the α-axis in a stationary two-phase coordinate system and an estimated value of a component of the stator flux vector on the β-axis in a stationary two-phase coordinate system; finally, the rotor position is determined based on multiple stator flux vector estimation values ​​and the calculated value of the stator flux vector, thereby reducing the recognition time of the rotor position when the synchronous motor is started and improving the recognition accuracy of the rotor position, thereby reducing the starting time of the synchronous motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the embodiments of this specification or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this specification. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0041] Figure 1 The figure is a flow chart of a method for determining the rotor position when a synchronous motor is started provided in an embodiment of the present specification;

[0042] Figure 2 The figure shows a schematic diagram of the structure of a device for determining the rotor position when a synchronous motor is started, provided in an embodiment of the present specification. DETAILED DESCRIPTION

[0043] In order to enable those skilled in the art to better understand the technical solutions in this specification, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are only part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of this application.

[0044] like Figure 1The flowchart of the method for determining the rotor position when the synchronous motor starts is shown in the embodiment of the present specification. Although the present specification provides the method operation steps or device structures shown in the following embodiments or drawings, the method or device may include more or fewer operation steps or module units after partial merger based on routine or no creative labor. In the steps or structures where there is no necessary causal relationship logically, the execution order of these steps or the module structure of the device is not limited to the execution order or module structure shown in the embodiments or drawings of the present specification. When the method or module structure is applied in an actual device, server or terminal product, it can be executed sequentially or in parallel according to the method or module structure shown in the embodiment or drawings (for example, in a parallel processor or multi-threaded processing environment, or even in a distributed processing, server cluster implementation environment).

[0045] The method for determining the rotor position of a synchronous motor when starting the synchronous motor provided in the embodiment of the present invention can be applied to various synchronous motors, such as Figure 1 As shown, the method specifically comprises the following steps:

[0046] Step S101, after injecting a voltage pulse into the α-axis or β-axis, a calculated value of a stator flux vector is determined, wherein the calculated value of a stator flux vector includes a calculated value of a component of the stator flux vector on the α-axis in a stationary two-phase coordinate system and a calculated value of a component of the stator flux vector on the β-axis in a stationary two-phase coordinate system.

[0047] In the embodiment of the present application, the step of injecting a voltage pulse into the α-axis or β-axis to determine the calculated value of the stator flux vector specifically includes:

[0048] After injecting a voltage pulse into the α-axis or β-axis, simultaneously collecting the stator current vector and the stator voltage vector, the stator current vector includes the component of the stator current vector on the α-axis in the stationary two-phase coordinate system and the component of the stator current vector on the β-axis in the stationary two-phase coordinate system, and the stator voltage vector includes the component of the stator voltage vector on the α-axis in the stationary two-phase coordinate system and the component of the stator voltage vector on the β-axis in the stationary two-phase coordinate system;

[0049] The stator flux vector calculation value is determined based on the stator current vector and the stator voltage vector.

[0050] Specifically, a voltage pulse can be injected into the α axis, where the amplitude and duration of the voltage pulse are limited to the motor not having an overcurrent fault. A voltage pulse can also be injected into the β axis, which can collect the stator current vector and stator voltage vector at the same time, thereby determining the calculated value of the stator flux vector.

[0051] Specifically, the calculated value of the stator flux vector is determined by the following formula:

[0052] ψ α (k) = ψ α (k-1)+T s (u α (k-2)-R s i α (k))

[0053] ψ β (k) = ψ β (k-1)+T s (u β (k-2)-R s i β (k))

[0054] In the formula, ψ α (k) is the calculated value of the α-axis component of the stator flux vector in the stationary two-phase coordinate system at the current beat k, ψ β (k) is the calculated value of the β-axis component of the stator flux vector in the stationary two-phase coordinate system at the previous beat of the current beat k, ψ α (k-1) is the calculated value of the α-axis component of the stator flux vector in the stationary two-phase coordinate system at the current beat k, ψ β (k-1) is the calculated value of the β-axis component of the stator flux vector in the stationary two-phase coordinate system at the previous beat of the current beat k, u α (k-2) is the sampling value of the stator voltage vector on the α-axis in the static two-phase coordinate system at the previous two beats of the current beat k, u β (k-2) is the sampling value of the stator voltage vector on the α-axis in the static two-phase coordinate system at the previous two beats of the current beat k, i α (k) is the sampling value of the stator current vector on the α-axis in the stationary two-phase coordinate system at the current beat k, i β (k) is the sampling value of the stator current vector on the β axis in the stationary two-phase coordinate system at the current beat k, R s is the stator resistance.

[0055] In the above, the stator current vector is obtained by sampling, and the stator voltage vector can be obtained by sampling or directly using a voltage command. When the voltage command is directly used, corresponding compensation can be optionally performed for the dead zone nonlinearity of the main circuit inverter.

[0056] Step S102, determining a plurality of stator flux vector estimation values ​​according to the position range of the rotor, wherein the stator flux vector estimation value comprises an α-axis component estimation value of the stator flux vector in a stationary two-phase coordinate system and a β-axis component estimation value of the stator flux vector in a stationary two-phase coordinate system.

[0057] In the embodiment of the present application, a plurality of stator flux vector estimation values ​​are determined according to the position range of the rotor, the position range is 0 degrees to 360 degrees, and the number of evenly divided first rotor positions also corresponds to the rotor position identification accuracy, specifically, evenly dividing a plurality of first rotor positions according to the position range, determining the stator flux vector estimation value according to the first rotor position, and determining the stator flux vector estimation value according to the first rotor position, which is specifically determined by the following formula:

[0058]

[0059] In the formula, ψ α i (k) is the estimated value of the α-axis component of the stator flux vector in the stationary two-phase coordinate system at the current beat k, ψ β i (k) is the estimated value of the β-axis component of the stator flux vector in the stationary two-phase coordinate system at the current beat k, θ i is the first rotor position, ψ d (k) is the direct axis flux at the current beat k, ψ q (k) is the cross-axis flux at the current beat k.

[0060] The direct-axis flux and the quadrature-axis flux at the current beat k are specifically determined by the following formula:

[0061] ψ d (k) = i d (k)×L d (i d (k),i q (k))+ψ f (k)

[0062] ψ q (k) = i q (k)×L q (i d (k),i q (k))

[0063] In the formula, i d (k) is the direct axis current at the current beat k, L d is the direct-axis inductance, i q (k) is the quadrature axis current at the current beat k, ψ f (k) is the permanent magnet flux amplitude or rotor excitation flux amplitude at the current beat k, i q (k) is the quadrature axis current at the current beat k, L q is the quadrature-axis inductance, i d (k) is the direct axis current at the current beat k.

[0064] Among them, the direct axis current and quadrature axis current in the above formula are the first rotor position θ i The coordinate transformation is as follows:

[0065]

[0066] In the formula, i α (k) is the sampling value of the stator current vector on the α-axis in the stationary two-phase coordinate system at the current beat k, i β (k) is the sampling value of the stator current vector on the β-axis in the stationary two-phase coordinate system at the current beat k.

[0067] In addition, in order to be compatible with various types of synchronous motors such as surface-mounted permanent magnet synchronous motors, built-in permanent magnet synchronous motors, embedded permanent magnet synchronous motors, permanent magnet assisted synchronous reluctance motors and synchronous reluctance motors, the motor saturation inductance can be used to estimate the motor stator flux linkage, that is, the AC and DC axis inductances are functions of the AC and DC axis currents, and the function expressions of the direct axis inductance and the quadrature axis inductance are L d and L q In practical applications, the fitting expression of the function or the saturation inductance curve table can be obtained through offline measurement or finite element analysis.

[0068] Step S103 : determining the rotor position based on a plurality of stator flux vector estimation values ​​and the stator flux vector calculation value.

[0069] The determining of the rotor position based on a plurality of stator flux vector estimation values ​​and the stator flux vector calculation value specifically includes:

[0070] Determining an error between the calculated value of the stator flux vector and each estimated value of the stator flux vector;

[0071] The first rotor position corresponding to the stator flux vector estimation value with the smallest error is used as the rotor position.

[0072] Specifically, after calculating a plurality of stator flux vector estimation values ​​and a stator flux vector calculation value, the error between the stator flux vector calculation value and each stator flux vector estimation value is calculated, which can be specifically shown in the following formula:

[0073] e(θ i )=(ψ α (k)-ψ α i (k))+(ψ β (k)-ψ β i (k))

[0074] For accurate numerical search, the error can also be changed to the square of the difference between the components, as shown in the following formula:

[0075] e(θ i )=(ψ α (k)-ψ α i (k)) 2 +(ψ β (k)-ψ β i (k)) 2

[0076] e(θ i ) is expressed as the error corresponding to the i-th first rotor position θ. The initial position angle of the synchronous motor, that is, the rotor position when the synchronous motor starts, is determined by minimizing the error.

[0077] In this application scheme, in one electrical cycle, that is, 0 degrees θ imin to 360 degreesθ imax Each angle in the interval corresponds to a unique stator flux vector. That is, when the error between the estimated value of the stator flux and the calculated value of the stator flux is the smallest, the position corresponding to the stator flux vector is the actual position angle of the motor. This method uses only a single voltage pulse, has low noise, fast identification speed, and does not require identification of the N / S pole position.

[0078] In order to determine the minimum error more quickly, the binary method can be used for determination, as shown below:

[0079]

[0080] Taking the binary search method as an example, by comparing the position estimates, the lower limit is θ imin and the upper limit of the position estimate, i.e., θ imax The size of the position estimation upper limit or the position estimation lower limit can be continuously updated until the difference between the upper and lower limits of the position estimation is less than the preset accuracy value, and the average value of the upper and lower limits of the position estimation at this time is taken as the rotor position. The preset accuracy value can be any value between 1 degree and 10 degrees, which is selected by technical personnel in this field.

[0081] In an embodiment of the present application, the method further includes:

[0082] When a plurality of groups of stator current vectors and stator voltage vectors are collected;

[0083] Determine a first variation between adjacent beats according to a stator flux vector calculation value determined by each group of stator current vectors and stator voltage vectors, and simultaneously determine a second variation between adjacent beats of all stator flux vector estimation values;

[0084] The rotor position is determined based on the first change amount and the second change amount.

[0085] Specifically, when a voltage pulse is injected into the α-axis or β-axis and the stator current vector and the stator voltage vector are collected, multiple sets of data may be collected, and then the following formula may be used to obtain:

[0086] ψ d (k-1)=i d (k-1)×L d (i d (k-1),i q (k-1))+ψ f (k-1)

[0087] ψ d (k)-ψ d (k-1)=i d (k)×L d (i d (k),i q (k))-i d (k-1)×L d (i d (k-1),i q (k-1))

[0088] In the formula, i d (k-1) is the direct axis current at the previous beat k-1, i q (k-1) is the quadrature axis current at the previous beat k-1, ψ f (k-1) is the permanent magnet flux amplitude or rotor excitation flux amplitude at the previous beat k-1, from which the following formula can be obtained:

[0089]

[0090] In the formula, Δψ α i (k) is the estimated value of the α-axis component of the stator flux vector change in the stationary two-phase coordinate system at the current beat, Δψ β i (k) is the estimated value of the β-axis component of the stator flux vector change in the stationary two-phase coordinate system at the current beat.

[0091] At the same time, it can be concluded that:

[0092] e(θ i )=(Δψ α (k)-Δψ α i (k)) 2 +(Δψ β (k)-Δψ β i (k)) 2

[0093] Specifically, according to the calculated value of the stator flux vector change Δψ α , Δψ β and the estimated value of the stator flux vector change Δψ α i , Δψ β i To construct the error function e(θi), and then realize the numerical search for the initial position of the synchronous motor. In one electrical cycle, each angle in the range of 0 to 360 degrees corresponds to a unique stator flux vector change. That is, when the error between the estimated value of the stator flux vector change and the calculated value of the stator flux vector change is the smallest, the stator flux vector change corresponds to the actual position angle of the motor, which is taken as the second error, and then the rotor positions corresponding to all the second errors are summed and averaged as the final rotor position.

[0094] Based on the above-mentioned method for determining the rotor position when the synchronous motor starts, one or more embodiments of this specification also provide a platform and terminal for determining the rotor position when the synchronous motor starts. The platform or terminal may include a device, software, module, plug-in, server, client, etc. that uses the method described in the embodiments of this specification and is combined with a necessary device for implementing hardware. Based on the same innovative concept, the system in one or more embodiments provided in the embodiments of this specification is as described in the following embodiments. Since the implementation scheme and method for solving the problem of the system are similar, the implementation of the specific system in the embodiments of this specification can refer to the implementation of the aforementioned method, and the repetitions will not be repeated. The terms "unit" or "module" used below can be a combination of software and / or hardware that implements predetermined functions. Although the system described in the following embodiments is preferably implemented in software, hardware and a combination of software and hardware are also possible and conceived.

[0095] Specifically, Figure 2 : is a schematic diagram of a module structure of an embodiment of a device for determining the rotor position when a synchronous motor is started provided in this specification, such as Figure 2 As shown, the device for determining the rotor position when the synchronous motor starts provided in this specification includes:

[0096] A first determination module 201 is used to determine a calculated value of a stator flux vector after injecting a voltage pulse into the α-axis or β-axis, wherein the calculated value of the stator flux vector includes a calculated value of a component of the stator flux vector on the α-axis in a stationary two-phase coordinate system and a calculated value of a component of the stator flux vector on the β-axis in a stationary two-phase coordinate system;

[0097] A second determination module 202 is used to determine a plurality of stator flux vector estimation values ​​according to the position range of the rotor, wherein the stator flux vector estimation value includes an α-axis component estimation value of the stator flux vector in a stationary two-phase coordinate system and a β-axis component estimation value of the stator flux vector in a stationary two-phase coordinate system;

[0098] The third determination module 203 is used to determine the rotor position based on a plurality of stator flux vector estimation values ​​and the stator flux vector calculation value.

[0099] It should be noted that the above-mentioned system may also include other implementation modes according to the description of the corresponding method embodiment. The specific implementation modes may refer to the description of the above-mentioned corresponding method embodiment, which will not be described one by one here.

[0100] The present application also provides an electronic device, including:

[0101] processor;

[0102] a memory for storing instructions executable by the processor;

[0103] The processor is configured to execute the method provided in the above embodiment.

[0104] The electronic device provided by the embodiment of the present application stores the executable instructions of the processor in the memory. When the processor executes the executable instructions, it can first inject a voltage pulse into the α-axis or β-axis and then determine the stator flux vector calculation value, the stator flux vector calculation value includes the component calculation value of the stator flux vector in the α-axis in the stationary two-phase coordinate system and the component calculation value of the stator flux vector in the β-axis in the stationary two-phase coordinate system; then determine multiple stator flux vector estimation values ​​according to the position range of the rotor, the stator flux vector estimation values ​​include the component estimation value of the stator flux vector in the α-axis in the stationary two-phase coordinate system and the component estimation value of the stator flux vector in the β-axis in the stationary two-phase coordinate system; finally, determine the rotor position based on the multiple stator flux vector estimation values ​​and the stator flux vector calculation value, which can reduce the recognition time of the rotor position when the synchronous motor is started, and improve the recognition accuracy of the rotor position, thereby reducing the start-up time of the synchronous motor. .

[0105] The above is a description of a specific embodiment of the specification. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recorded in the claims can be performed in an order different from that in the embodiments and still achieve the desired results. In addition, the processes depicted in the drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0106] The methods or devices described in the above embodiments provided in this specification can implement business logic through computer programs and record them on storage media, and the storage media can be read and executed by computers to achieve the effects of the solutions described in the embodiments of this specification, such as:

[0107] After injecting a voltage pulse into the α-axis or β-axis, a calculated value of a stator flux vector is determined, wherein the calculated value of the stator flux vector includes a calculated value of a component of the stator flux vector on the α-axis in a stationary two-phase coordinate system and a calculated value of a component of the stator flux vector on the β-axis in a stationary two-phase coordinate system;

[0108] Determine a plurality of stator flux vector estimation values ​​according to the position range of the rotor, wherein the stator flux vector estimation value includes an α-axis component estimation value of the stator flux vector in a stationary two-phase coordinate system and a β-axis component estimation value of the stator flux vector in a stationary two-phase coordinate system;

[0109] The rotor position is determined based on a plurality of stator flux vector estimation values ​​and the stator flux vector calculation value.

[0110] The storage medium may include a physical device for storing information, which is usually a medium that digitizes information and then stores it in an electrical, magnetic or optical manner. The storage medium may include: a device that stores information in an electrical energy manner, such as various memories, such as RAM, ROM, etc.; a device that stores information in a magnetic energy manner, such as a hard disk, a floppy disk, a magnetic tape, a magnetic core memory, a magnetic bubble memory, a USB flash drive; a device that stores information in an optical manner, such as a CD or a DVD. Of course, there are other readable storage media, such as quantum memory, graphene memory, etc.

[0111] The controller can be implemented in any appropriate manner, for example, the controller can take the form of a computer-readable medium such as a microprocessor or processor and a computer-readable program code (such as software or firmware) that can be executed by the (micro)processor, a logic gate, a switch, an application specific integrated circuit (ASIC), a programmable logic controller, and an embedded microcontroller. Examples of controllers include, but are not limited to, the following microcontrollers: ARC 625D, ATMEL AT91SAM, MICROCHIP PIC18F26K20, and SILICONE LABS C8051F320. The memory controller can also be implemented as part of the control logic of the memory. It is also known to those skilled in the art that in addition to implementing the controller in a purely computer-readable program code manner, the controller can be implemented in the form of a logic gate, a switch, an application specific integrated circuit, a programmable logic controller, and an embedded microcontroller by logically programming the method steps. Therefore, such a controller can be considered as a hardware component, and the devices included therein for implementing various functions can also be considered as structures within the hardware component. Or even, the devices for implementing various functions can be considered as both software modules for implementing the method and structures within the hardware component.

[0112] The device embodiments described above are merely illustrative. For example, the division of the units is merely a logical function division. There may be other divisions in actual implementation, such as multiple units or plug-ins may be combined or integrated into another system, or some features may be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed may be through some interface, indirect coupling or communication connection of the device or unit, which may be electrical, mechanical or other forms.

[0113] Each embodiment in this specification is described in a progressive manner, and the same and similar parts between the embodiments can be referenced to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can refer to the partial description of the method embodiment. In the description of this specification, the description of the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of this specification. In this specification, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples without contradiction.

[0114] Those skilled in the art will appreciate that the embodiments described herein are intended to help readers understand the principles of the present invention, and should be understood that the protection scope of the present invention is not limited to such specific statements and embodiments. Those skilled in the art can make various other specific variations and combinations that do not deviate from the essence of the present invention based on the technical revelations disclosed by the present invention, and these variations and combinations are still within the protection scope of the present invention.

Claims

1. A method for determining the rotor position when a synchronous motor is started, characterized in that: The method comprises: After injecting a voltage pulse into the α-axis or β-axis, a calculated value of a stator flux vector is determined, wherein the calculated value of the stator flux vector includes a calculated value of a component of the stator flux vector on the α-axis in a stationary two-phase coordinate system and a calculated value of a component of the stator flux vector on the β-axis in a stationary two-phase coordinate system; Determine a plurality of stator flux vector estimation values ​​according to the position range of the rotor, wherein the stator flux vector estimation value includes an α-axis component estimation value of the stator flux vector in a stationary two-phase coordinate system and a β-axis component estimation value of the stator flux vector in a stationary two-phase coordinate system; The rotor position is determined based on a plurality of stator flux vector estimation values ​​and the stator flux vector calculation value.

2. The method for determining the rotor position when a synchronous motor is started as claimed in claim 1, characterized in that: The determining of a plurality of stator flux vector estimation values ​​according to the position range of the rotor specifically includes equally dividing a plurality of first rotor positions according to the position range, and determining the stator flux vector estimation value according to the first rotor positions.

3. The method for determining the rotor position when a synchronous motor is started as claimed in claim 2, characterized in that: The stator flux vector estimation value is determined according to the first rotor position, specifically by the following formula: In the formula, ψ α i (k) is the estimated value of the α-axis component of the stator flux vector in the stationary two-phase coordinate system at the current beat k, ψ β i (k) is the estimated value of the β-axis component of the stator flux vector in the stationary two-phase coordinate system at the current beat k, θ i is the first rotor position, ψ d (k) is the direct axis flux at the current beat k, ψ q (k) is the cross-axis flux at the current beat k.

4. The method for determining the rotor position when a synchronous motor is started as claimed in claim 3, characterized in that: The direct-axis flux and the quadrature-axis flux at the current beat k are specifically determined by the following formula: ψ d (k)=i d (k)×L d (i d (k),i q (k))+ψ f (k) ψ q (k)=i q (k)×L q (i d (k),i q (k)) In the formula, i d (k) is the direct axis current at the current beat k, L d is the direct-axis inductance, i q (k) is the quadrature axis current at the current beat k, ψ f (k) is the permanent magnet flux amplitude or rotor excitation flux amplitude at the current beat k, i q (k) is the quadrature axis current at the current beat k, L q is the quadrature-axis inductance, i d (k) is the direct axis current at the current beat k.

5. The method for determining the rotor position when a synchronous motor is started as claimed in claim 1, characterized in that: Determining the calculated value of the stator flux vector after injecting a voltage pulse into the α-axis or the β-axis specifically includes: After injecting a voltage pulse into the α-axis or β-axis, simultaneously collecting the stator current vector and the stator voltage vector, the stator current vector includes the component of the stator current vector on the α-axis in the stationary two-phase coordinate system and the component of the stator current vector on the β-axis in the stationary two-phase coordinate system, and the stator voltage vector includes the component of the stator voltage vector on the α-axis in the stationary two-phase coordinate system and the component of the stator voltage vector on the β-axis in the stationary two-phase coordinate system; The stator flux vector calculation value is determined based on the stator current vector and the stator voltage vector.

6. The method for determining the rotor position when a synchronous motor is started as claimed in claim 5, characterized in that: Specifically, the calculated value of the stator flux vector is determined by the following formula: ψ α (k)=ψ α (k-1)+T s (u α (k-2)-R s I α (k)) ψ β (k)=ψ β (k-1)+T s (u β (k-2)-R s I β (k)) In the formula, ψ α (k) is the calculated value of the α-axis component of the stator flux vector in the stationary two-phase coordinate system at the current beat k, ψ β (k) is the calculated value of the β-axis component of the stator flux vector in the stationary two-phase coordinate system at the previous beat of the current beat k, ψ α (k-1) is the calculated value of the α-axis component of the stator flux vector in the stationary two-phase coordinate system at the current beat k, ψ β (k-1) is the calculated value of the β-axis component of the stator flux vector in the stationary two-phase coordinate system at the previous beat of the current beat k, u α (k-2) is the sampling value of the stator voltage vector on the α-axis in the stationary two-phase coordinate system at the previous two beats of the current beat K, u β (k-2) is the sampling value of the stator voltage vector on the α-axis in the static two-phase coordinate system at the previous two beats of the current beat k, i α (k) is the sampling value of the stator current vector on the α-axis in the stationary two-phase coordinate system at the current beat k, i β (k) is the sampling value of the stator current vector on the β axis in the stationary two-phase coordinate system at the current beat k, R s is the stator resistance.

7. The method for determining the rotor position when a synchronous motor is started as claimed in claim 1, characterized in that: The determining of the rotor position based on a plurality of stator flux vector estimation values ​​and the stator flux vector calculation value specifically includes: Determining an error between the calculated value of the stator flux vector and each estimated value of the stator flux vector; The first rotor position corresponding to the stator flux vector estimation value with the smallest error is used as the rotor position.

8. The method for determining the rotor position when a synchronous motor is started as claimed in claim 7, characterized in that: The method further comprises: When a plurality of groups of stator current vectors and stator voltage vectors are collected; Determine a first variation between adjacent beats according to a stator flux vector calculation value determined by each group of stator current vectors and stator voltage vectors, and simultaneously determine a second variation between adjacent beats of all stator flux vector estimation values; The rotor position is determined based on the first change amount and the second change amount.

9. The method for determining the rotor position when a synchronous motor is started as claimed in claim 8, characterized in that: Each second variation corresponds to an angle, and determining the rotor position based on the first variation and the second variation specifically includes: Determine the error between each first variation and all second variations and use the smallest error as the second error; The rotor positions corresponding to all the second errors are summed and averaged to obtain the final rotor position.

10. A device for determining the rotor position when a synchronous motor is started, characterized in that: The device comprises: A first determination module is used to determine a stator flux vector calculation value after injecting a voltage pulse into the α-axis or β-axis, wherein the stator flux vector calculation value includes a component calculation value of the stator flux vector in the α-axis in a stationary two-phase coordinate system and a component calculation value of the stator flux vector in the β-axis in a stationary two-phase coordinate system; a second determination module, configured to determine a plurality of stator flux vector estimation values ​​according to a rotor position range, wherein the stator flux vector estimation value includes an α-axis component estimation value of the stator flux vector in a stationary two-phase coordinate system and a β-axis component estimation value of the stator flux vector in a stationary two-phase coordinate system; The third determination module is used to determine the rotor position based on a plurality of stator flux vector estimation values ​​and the stator flux vector calculation value.

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