Position compensation method, device and system for a synchronous machine without position control

Abstract

This invention discloses a position compensation method, apparatus, and system for a synchronous motor without position control, belonging to the field of synchronous motor parameter identification, including: injecting a frequency of ω into the command voltage of its d and q axes respectively during motor operation. h The disturbance voltage was measured; three-phase current and three-phase voltage were collected and transformed to the γ1-δ1 and γ2-δ2 coordinate systems respectively to obtain the voltage signal and the corresponding current signal in each coordinate system, and the frequency ω was extracted from them. h The small-signal voltage and corresponding small-signal current are used to calculate the observed incremental inductance in the γ1-δ1 and γ2-δ2 coordinate systems, according to the observation error θ caused by the calculation parameter error. γ1d And compensate; the γ1-δ1 and γ2-δ2 coordinate systems rotate at the same speed as the dq rotating coordinate system, with an angle difference of θ respectively. γ1d and θ γ1d +ε. This invention enables accurate identification of all parameters during the positionless operation of a synchronous motor and improves the accuracy of positionless control.

Description

Technical Field

[0001] This invention belongs to the field of synchronous motor parameter identification, and more specifically, relates to a position compensation method, apparatus and system for synchronous motors without position control. Background Technology

[0002] Synchronous motors, due to their high power density and high efficiency, are widely used in various industrial and daily life applications, such as household appliances, compressors, blowers, and fuel pumps. When performing closed-loop field-oriented control of a synchronous motor, real-time rotor position information is required. Typical motor control systems obtain position information by adding position sensors such as photoelectric encoders or rotary transformers to the motor rotor shaft. While this simplifies the control algorithm, it introduces two problems: additional position sensors increase the overall system cost and motor size, making them unsuitable for low-cost applications such as household appliances; in automotive and aerospace applications, additional position sensors introduce additional electromagnetic interference, mechanical vibration, and heat resistance issues, reducing system reliability. Therefore, in specific application scenarios, eliminating rotor position sensors and employing a position-free control algorithm to control permanent magnet motors is significant for reducing system cost and improving reliability.

[0003] With the advancement of power electronics technology and the development of digital processors, sensorless control methods have been widely adopted. Among these, the position observer based on the fundamental frequency back EMF model is the most widely used method, and its observer expression is as follows:

[0004]

[0005] In equation (1), the superscript “^” represents the observed value of the parameter, the superscript “·” represents the derivative of the parameter with respect to time, and the superscript “~” represents the error between the observed value of the parameter and the true value. This represents the apparent inductance along the q-axis, specifically the magnetic flux linkage ψ generated by current excitation along the q-axis. qe Divide by the current i along the q-axis q ,Right now =ψ qe / i q ;R s Indicates the motor resistance, u αβ =[u α u β ] T Indicates the motor voltage under the αβ axis, i αβ =[i α i β ] T Represents the motor current under the αβ axis, e αβ =[e α e β ] Tω represents the back electromotive force of the motor along the αβ axis. e Indicates the fundamental frequency of the motor; Represents the identity matrix. Let represent the transformation matrix, K represent the current sensor feedback matrix, and T represent the back EMF observer feedback matrix; Represents a symbolic function;

[0006] Based on equation (1), the observed rotor position can be obtained through equation (2) or by means of a phase-locked loop, etc.

[0007]

[0008] In equation (2), The observed position of the motor rotor.

[0009] The above method can achieve rotor position observation without relying on rotor position sensors. However, this method has a serious problem: the accuracy of position observation directly depends on the accuracy of the parameters in the mathematical model under the real-time operating state of the motor, that is, it depends on the resistance R. s With apparent inductance The accuracy, if the resistance R s With apparent inductance If there are errors in identification, then there will also be errors in the observation of the transpose position.

[0010] Some studies have already indicated that, under the premise of ensuring parameter convergence conditions, it is possible to achieve resistance R. s With apparent inductance One of them converges while the other parameter remains constant, and its observer formula is shown in (3). However, this does not meet the requirements of full parameter identification because the observation result of one parameter is still affected by the given value of the other parameter.

[0011]

[0012] Furthermore, the above model is based on the assumption of linear flux linkage at the fundamental frequency, and does not take into account nonlinear factors under high load and high dynamics. This leads to significant errors in position observations under high load conditions. Summary of the Invention

[0013] In view of the deficiencies and improvement needs of the existing technology, the present invention provides a position compensation method, device and system for synchronous motors without position control. The purpose is to achieve accurate identification of all parameters of the synchronous motor during the operation of the synchronous motor without position and to improve the accuracy of the control without position.

[0014] To achieve the above objectives, according to one aspect of the present invention, a position compensation method for a synchronous motor without position control is provided, comprising:

[0015] Disturbance injection steps: During motor operation, inject a frequency of ω into the command voltages of its d and q axes respectively. h The disturbance voltage; ω h ≠6nω e ω e This represents the fundamental frequency of the motor, where n is a positive integer;

[0016] The parameter error compensation steps include:

[0017] (S1) Collect the three-phase current and three-phase voltage under the motor's operating state, and transform them to the γ1-δ1 coordinate system and the γ2-δ2 coordinate system respectively to obtain the voltage signal u with disturbance in each coordinate system. γi and u δi and the voltage signal u γi and u δi The current signal i generated by the excitation γi and i δi ;

[0018] Both the γ1-δ1 and γ2-δ2 coordinate systems have the same synchronous rotational speed as the dq rotating coordinate system, and each has an angular difference θ from the dq rotating coordinate system. γ1d and θ γ1d +ε,θ γ1d The position observation error is due to parameter error, ε is the preset angle, and ε≠0;

[0019] (S2) Filter out u γi u δi i γi and i δi The intermediate frequency is not equal to ω h The components are used to obtain the small signal voltage u. γih and u δih And in small signal voltage u γih and u δih Small signal current i under excitation γih and i δih ;

[0020] (S3) Utilizing small signal voltage u γih and u δih Small signal current i γih and i δih Calculate the incremental inductance observed in the γ1-δ1 and γ2-δ2 coordinate systems respectively. and

[0021] (S4) According to Calculate the position observation error θ caused by parameter errors. γ1d And provide compensation;

[0022] Where i = 1 or 2; when i = 1, u γi u δi i γi i δi u γih u δih i γih and i δih All signals are in the γ1-δ1 coordinate system; when i=2, u γi u δi i γi i δi u γih u δih i γih and i δih All signals are in the γ2-δ2 coordinate system; To observe the incremental inductance, let represent the derivative of the flux linkage along the x-axis with respect to the current along the y-axis in the same coordinate system.

[0023] Furthermore, ε = 45°.

[0024] Furthermore, step (S3) also includes: utilizing a small signal voltage u γih and u δih Small signal current i γih and i δih Calculate the motor winding R s ;

[0025] Furthermore, the position compensation method for a synchronous motor without position control provided by the present invention further includes a dynamic compensation step after the parameter error compensation step;

[0026] The dynamic compensation steps include:

[0027] according to Calculate and compensate for the position observation error Δθ caused by magnetic flux nonlinearity;

[0028] Among them, u d and u q These represent the d-axis voltage and the q-axis voltage, respectively; i d and i q These represent the d-axis current and the q-axis current, respectively. and Representing i respectively d and i q The derivative of ψ d and ψ q These represent the d-axis flux linkage and the q-axis flux linkage, respectively. Let q be the apparent inductance along the q-axis, and let q be the flux linkage generated by current excitation along the q-axis divided by the current along the q-axis.

[0029] According to another aspect of the present invention, a position compensation device for a synchronous motor without position control is provided, comprising: a disturbance injection module and a parameter error compensation module;

[0030] The disturbance injection module is used to inject a frequency of ω into the command voltages of the d and q axes of the motor during operation. h The disturbance voltage; ω h ≠6nω e ω e This represents the fundamental frequency of the motor, where n is a positive integer;

[0031] The parameter error compensation module includes:

[0032] A voltage sensor, connected to a synchronous motor, is used to collect the three-phase voltage during motor operation.

[0033] A current sensor, connected to a synchronous motor, is used to collect the three-phase current during motor operation.

[0034] The coordinate transformation module, connected to the voltage and current sensors respectively, is used to transform the three-phase current and three-phase voltage during motor operation to the γ1-δ1 and γ2-δ2 coordinate systems, respectively, to obtain the voltage signal u with disturbance in each coordinate system. γi and u δi and the voltage signal u γi and u δi The current signal i generated by the excitation γi and i δi Both the γ1-δ1 and γ2-δ2 coordinate systems have the same synchronous rotational speed as the dq rotating coordinate system, and each has an angular difference θ from the dq rotating coordinate system. γ1d and θ γ1d +ε,θ γ1d The position observation error is due to parameter error, ε is the preset angle, and ε≠0;

[0035] A bandpass filter, connected to the coordinate transformation module, is used to filter out u. γi u δi i γi and i δi The intermediate frequency is not equal to ω h The components are used to obtain the small signal voltage u. γih and u δih And in small signal voltage u γih and u δih Small signal current i under excitation γih and i δih ;

[0036] The incremental inductance calculation unit, connected to a bandpass filter, is used to utilize the small-signal voltage u. γihand u δih Small signal current i γih and i δih Calculate the incremental inductance observed in the γ1-δ1 and γ2-δ2 coordinate systems respectively. and

[0037] And a parameter error compensation unit, connected to the observation increment inductance calculation unit, used to calculate according to... Calculate the position observation error θ caused by parameter errors. γ1d And provide compensation;

[0038] Where i = 1 or 2; when i = 1, u γi u δi i γi i δi u γih u δih i γih and i δih All signals are in the γ1-δ1 coordinate system; when i=2, u γi u δi i γi i δi u γih u δih i γih and i δih All signals are in the γ2-δ2 coordinate system; To observe the incremental inductance, let represent the derivative of the flux linkage along the x-axis with respect to the current along the y-axis in the same coordinate system.

[0039] Furthermore, ε = 45°.

[0040] Furthermore, the incremental inductance calculation unit is also used to utilize small-signal voltage u γih and u δih Small signal current i γih and i δih Calculate the motor winding R s ;

[0041] Furthermore, the position compensation device for a synchronous motor without position control provided by the present invention further includes: a dynamic compensation module, used to... Calculate and compensate for the position observation error Δθ caused by magnetic flux nonlinearity;

[0042] Among them, u d and u q These represent the d-axis voltage and the q-axis voltage, respectively; i d and i q These represent the d-axis current and the q-axis current, respectively. and Representing i respectivelyd and i q The derivative of ψ d and ψ q These represent the d-axis flux linkage and the q-axis flux linkage, respectively. Let q be the apparent inductance along the q-axis, and let q be the flux linkage generated by current excitation along the q-axis divided by the current along the q-axis.

[0043] According to another aspect of the present invention, a synchronous motor system without position control is provided, comprising:

[0044] Synchronous motor;

[0045] A position observer, connected to the synchronous motor, is used to obtain the rotor position observation value of the synchronous motor;

[0046] The present invention also provides a position compensation device for a synchronous motor without position control, which is connected to both the synchronous motor and the position observer, and is used to calculate and compensate for errors in the rotor position observation values.

[0047] In summary, the above-described technical solutions conceived in this invention can achieve the following beneficial effects:

[0048] (1) After injecting a disturbance into the operating motor voltage command value, the present invention is based on the rotor position observation error θ caused by parameter error. γ1d Establish a γ1-δ1 rotating coordinate system with the same rotational speed as the dq rotating coordinate system, and establish a virtual synchronous γ2-δ2 coordinate system with an assumed angle difference ε from the γ1-δ1 coordinate system. Analyze the small-signal voltage u generated by the injected disturbance in these two coordinate systems. γih and u δih With small signal current i γih and i δih The observed incremental inductance information is calculated, and finally, the rotor position observation error θ caused by the parameter error is calculated based on the observed incremental inductance information. γ1d The error is compensated for, thereby enabling accurate identification of all parameters during the positionless operation of the synchronous motor and improving the accuracy of positionless control.

[0049] (2) In a preferred embodiment of the present invention, the angular difference ε between the established virtual synchronous rotating coordinate system γ2-δ2 and the coordinate system γ1-δ1 is specifically set to 45°. In this case, the calculation expression for the rotor position observation error caused by parameter error will be simplified to: This greatly simplifies the computational complexity and improves computational efficiency.

[0050] (3) In the preferred embodiment of the present invention, after compensating for the rotor position observation error caused by parameter error, the nonlinear characteristics of the fundamental frequency flux linkage are further considered, the rotor position observation error Δθ caused by the nonlinear assumption of the fundamental frequency flux linkage is calculated and compensated, so that the present invention can accurately obtain the rotor position under heavy load and high dynamic conditions. Therefore, the present invention can realize accurate identification of all parameters in the synchronous motor without position operation under all working conditions and improve the accuracy and dynamic performance of the positionless controller. Attached Figure Description

[0051] Figure 1 This is a schematic diagram of the coordinate system provided in an embodiment of the present invention;

[0052] Figure 2 This is a schematic diagram of disturbance injection provided in an embodiment of the present invention;

[0053] Figure 3 This is a schematic diagram of parameter error compensation and dynamic compensation provided in an embodiment of the present invention. Detailed Implementation

[0054] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0055] In this invention, the terms "first," "second," etc. (if present) in the invention and the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0056] To effectively improve the accuracy of rotor position observation, this invention provides a position compensation method, device, and system for synchronous motors without position control. The overall approach is to accurately analyze and compensate for errors in the rotor position observed by existing model-based rotor position observers. The observation errors compensated by this invention include two aspects: first, rotor position observation errors caused by parameter errors; and second, errors caused by existing models neglecting flux nonlinearity.

[0057] Before explaining the technical solution of the present invention in detail, the above two types of errors are analyzed as follows.

[0058] Based on the model shown in formula (1), considering the nonlinearity of the magnetic flux of the synchronous motor, the mathematical model of the synchronous motor can be obtained as shown in formula (4):

[0059]

[0060] Among them, incremental inductance ψ is the magnetic flux linkage along the x-axis. x For the y-axis current i y The derivative of Apparent inductance Let ψ be the magnetic flux linkage generated by current excitation along the x-axis. xe Divide by the current i along the x-axis x , Let ψ be the axis in the rotating coordinate system; the two axes can be the same or different. dm Let be the permanent magnet flux linkage on the d-axis. Based on the calculation methods for incremental inductance and apparent inductance, it can be seen that due to the saturation and cross-coupling characteristics of the flux linkage on the dq-axis, the incremental inductance and apparent inductance are not equal.

[0061] Based on formula (4), the small-signal model and large-signal model of the synchronous motor in the synchronous coordinate system can be obtained by Taylor expansion as shown in (5) and (6), respectively.

[0062]

[0063]

[0064] Among them, u x0 and i x0 These are the voltage and current signals of the motor under steady-state operation, u xh and i xh These are the steady-state operating voltage and current u, respectively. x0 and i x0 Nearby voltage and current disturbances, where x is the d-axis or q-axis in a rotating coordinate system.

[0065] Let θ be the position observation error caused by parameter errors. γ1d Establish a γ1-δ1 coordinate system, such as Figure 1 As shown, the γ1-δ1 coordinate system and the dq rotating coordinate system have the same synchronous rotational speed ω. e Furthermore, the γ1 axis and δ1 axis have angular differences θ with the d and q axes, respectively. γ1d .

[0066] Transform the small-signal model shown in formula (5) to the γ1-δ1 coordinate system, which has angular observation errors, to obtain the small-signal model in the γ1-δ1 coordinate system, as shown in formula (7):

[0067]

[0068] Among them, P γ1δ1-dq Let be the Park transformation matrix from the dq coordinate system to the γ1-δ1 coordinate system. Based on P γ1δ1-dqThe expression, formula (7), can be further expressed as formula (8):

[0069]

[0070] in, and All are incremental inductances in the γ1-δ1 coordinate system, and the relevant expressions are as follows:

[0071]

[0072] like Figure 1 As shown, a virtual synchronous coordinate system, namely the γ2-δ2 coordinate system, is constructed that has an angular difference of ε from the γ1-δ1 coordinate system; the γ2-δ2 coordinate system and the dq rotating coordinate system have the same synchronous rotational speed ω. e Furthermore, the γ2 axis and δ2 axis have angular differences θ with the d and q axes, respectively. γ2d =θ γ1d +ε, where ε is any given value other than zero. Referring to the analysis method of the γ1-δ1 coordinate system above, the expression for the incremental inductance in the γ2-δ2 coordinate system can be obtained as shown in formula (10).

[0073]

[0074] By transforming the incremental inductance formulas shown in formulas (9) and (10), we can obtain the following expression:

[0075]

[0076]

[0077] Where i = 1 or 2; when i = 1, θ γid All parameters are in the γ1-δ1 coordinate system; when i=2, θ γid All parameters are in the γ2-δ2 coordinate system.

[0078] Multiply (11.a) by sin2θ γid Add (11.b) multiplied by cos2θ γid We can obtain (12):

[0079]

[0080] therefore,

[0081]

[0082] Based on formula (13), the incremental inductance in the γ1-δ1 and γ2-δ2 coordinate systems can be calculated. and Then, by combining the assumed angle difference ε, the rotor position observation error θ caused by parameter errors can be calculated. γ1d This is then compensated for in the rotor position observation values ​​obtained by the actual position observation algorithm. The incremental inductance in the γ1-δ1 and γ2-δ2 coordinate systems... and The identification method can be found in "Improved Small-Signal Injection-Based Online Multiparameter Identification Method for IPM Machines Considering Cross-Coupling Magnetic Saturation" (Z. Liu, X. Fan, W. Kong, L. Cao and R. Qu, in IEEE Transactions on Power Electronics, vol. 37, no. 12, pp. 14362-14374, Dec. 2022), and will not be repeated here. Referring to the calculation method in that paper, the incremental inductance in the γ1-δ1 and γ2-δ2 coordinate systems is identified. and At the same time, it can also complete the motor resistance R s Identification;

[0083] Further analysis revealed that if ε is chosen as 45°, the position observation error θ caused by parameter errors will increase. γ1d It can be expressed as formula (14).

[0084]

[0085] Next, we analyze the rotor position observation error caused by the nonlinearity of the flux linkage. The motor model considering the nonlinearity of the flux linkage shown in Equation (4) is rewritten in the form of extended electromotive force (EMF), as shown in Equation (15).

[0086]

[0087] The inverse Park transformation is used to transform formula (15) to the α-β coordinate system for subsequent back electromotive force and rotor position observation and analysis. The transformed formula is shown in formula (16).

[0088]

[0089] Currently, the mathematical model used by the widely used back EMF observer is based on the "active flux" model, as shown in formula (17), which assumes that the flux currents are all linear.

[0090]

[0091] In formula (17), 2Δθ e This is due to the rotor position observation error caused by the linearity assumption of the magnetic flux. It is worth noting that even the resistance R in (17) s With apparent inductance L apq All values ​​are true, so this error still exists.

[0092] By comparing formulas (17) and (16), it can be found that the existing back potential observer has the following two problems:

[0093] 1. It neglects flux saturation and cross-coupling, ignores the incremental inductance matrix along the dq axis, and only the apparent inductance is considered.

[0094] 2. In the design of the state observer, the transient state ψ is ignored. active That is, dψ active / dt=0.

[0095] αβ axis motor current i αβ The expression is shown in formula (18).

[0096]

[0097] By using the motor current i under the αβ axis as shown in formula (18) αβ Substituting the expressions into formulas (16) and (17), the error between the two models can be expressed as formula (19).

[0098]

[0099] The column phasor elements in (19) are represented as follows:

[0100]

[0101]

[0102] Further analysis of (20) yields the following results:

[0103]

[0104]

[0105] Based on formula (21), the rotor position error caused by the "active flux linkage" model compared with the flux linkage nonlinear model can be finally expressed as (22).

[0106]

[0107] in,

[0108]

[0109] The following is an example.

[0110] Example 1:

[0111] A position compensation method for a synchronous motor without position control includes: a disturbance injection step and a parameter error compensation step.

[0112] In this embodiment, the disturbance injection step includes:

[0113] During motor operation, a frequency of ω is injected into the command voltages of its d and q axes, respectively. h The disturbance voltage; ω h ≠6nω e ω e This represents the fundamental frequency of the motor, where n is a positive integer.

[0114] In practical applications, such as Figure 2 As shown, the d-axis and q-axis command voltages output by the current loop are... and The injection frequency is ω h Disturbance voltage u dh and u qh Disturbance injection is implemented. Through disturbance injection, the rotor position observation error can be analyzed using a small-signal model. It is easy to understand that, in order to reduce the impact on the electrode output torque, the amplitude of the injected disturbance voltage should be as small as possible. Specifically, a threshold can be set, and the ratio of the amplitude of the rotating high-frequency voltage to the rated voltage must not exceed this threshold. This threshold can be set according to the operating characteristics of the permanent magnet synchronous motor to be identified and the motor parameter identification requirements in the actual application. Optionally, in the following embodiment, this threshold is 10%.

[0115] Meanwhile, to avoid generating odd-order harmonics in the ABC three phases of the motor, the frequency ω of the rotating high-frequency voltage injected in this invention is... h ≠6nω e n is a positive integer; in this invention, ω h / ω e ∈[3,5]; Optionally, in the following embodiments, the d-axis high-frequency voltage u dh and q-axis high-frequency voltage u qh frequency ω h =3ωe Then, even harmonics with frequencies of 2 and 4 will be generated in the three phases ABC.

[0116] like Figure 3 As shown, in this embodiment, the parameter error compensation step includes:

[0117] (S1) Collect the three-phase current and three-phase voltage under the motor's operating state, and transform them to the γ1-δ1 coordinate system and the γ2-δ2 coordinate system respectively to obtain the voltage signal u with disturbance in each coordinate system. γi and u δi and the voltage signal u γi and u δi The current signal i generated by the excitation γi and i δi ;

[0118] Both the γ1-δ1 and γ2-δ2 coordinate systems have the same synchronous rotational speed as the dq rotating coordinate system, and each has an angular difference θ from the dq rotating coordinate system. γ1d and θ γ1d +ε,θ γ1d This refers to the position observation error caused by parameter errors;

[0119] ε is a preset angle, ε≠0; in order to simplify the calculation and improve the calculation efficiency, as a preferred implementation, in this embodiment, ε=45°;

[0120] (S2) Filter out u γi u δi i γi and i δi The intermediate frequency is not equal to ω h The components are used to obtain the small signal voltage u. γih and u δih And in small signal voltage u γih and u δih Small signal current i under excitation γih and i δih ;

[0121] (S3) Utilizing small signal voltage u γih and u δih Small signal current i γih and i δih Calculate the incremental inductance observed in the γ1-δ1 and γ2-δ2 coordinate systems respectively. and

[0122] (S4) According to Calculate the position observation error θ caused by parameter errors. γ1d And provide compensation;

[0123] Where i = 1 or 2; when i = 1, u γi u δi i γi i δi u γih u δih i γih and i δih Both are signals in the γ1-δ1 coordinate system; when i=2, u γi u δi i γi i δi u γih u δih i γih and i δih All signals are in the γ2-δ2 coordinate system; To observe the incremental inductance, let represent the derivative of the flux linkage along the x-axis with respect to the current along the y-axis in the same coordinate system.

[0124] It is easy to understand that the position observation error θ caused by parameter errors is calculated. γ1d Subsequently, the rotor position is observed from the model-based rotor position observer. The error can be subtracted from the result to achieve compensation.

[0125] It should be noted that ε = 45° is only a preferred embodiment and should not be construed as the sole limitation of the present invention. When ε is set to other non-zero values, the position observation error θ caused by the parameter error is calculated according to formula (13). γ1d That's all.

[0126] Considering that existing model-based rotor position observers, which assume linear flux linkage at the fundamental frequency, can lead to significant rotor position observation errors under heavy load and high dynamic operation, this embodiment, as a preferred implementation, addresses the rotor position observation error θ caused by parameter errors. γ1d After compensation, the rotor position observation error caused by flux nonlinearity is further calculated and compensated to further improve the observation accuracy of the rotor position and enhance the dynamic characteristics of the observation. Specifically, such as... Figure 3 As shown, this embodiment further includes a dynamic compensation step after the parameter error compensation step;

[0127] The dynamic compensation steps include:

[0128] according to Calculate and compensate for the position observation error Δθ caused by the nonlinearity of the magnetic flux; Δθ is 2Δθ in formula (22). e ;

[0129] Among them, R s Indicates winding resistance; ud and u q These represent the d-axis voltage and the q-axis voltage, respectively; i d and i q These represent the d-axis current and the q-axis current, respectively. and Representing i respectively d and i q The derivative of ψ d and ψ q These represent the d-axis flux linkage and the q-axis flux linkage, respectively. Let q be the apparent inductance along the q-axis, and let q be the flux linkage generated by current excitation along the q-axis divided by the current along the q-axis.

[0130] Similarly, after calculating the position observation error Δθ caused by flux nonlinearity, the rotor position observed from the model-based rotor position observer is... The error can be subtracted from the result to achieve compensation.

[0131] This embodiment identifies and compensates for rotor position observation errors caused by magnetic flux nonlinearity, enabling accurate rotor position observation of the synchronous motor even under heavy load and high dynamic conditions. Furthermore, the rotor position compensation in this embodiment relies on incremental inductance and motor resistance, parameters that can be accurately identified using existing technologies. Therefore, this embodiment achieves accurate identification of all parameters during the positionless operation of the synchronous motor under all operating conditions, effectively improving the accuracy and dynamic performance of the positionless controller.

[0132] Example 2:

[0133] A position compensation device for a synchronous motor without position control includes: a disturbance injection module and a parameter error compensation module;

[0134] The disturbance injection module is used to inject a frequency of ω into the command voltages of the d and q axes of the motor during operation. h The disturbance voltage; ω h ≠6nω e ω e This represents the fundamental frequency of the motor, where n is a positive integer;

[0135] The parameter error compensation module includes:

[0136] A voltage sensor, connected to a synchronous motor, is used to collect the three-phase voltage during motor operation.

[0137] A current sensor, connected to a synchronous motor, is used to collect the three-phase current during motor operation.

[0138] The coordinate transformation module, connected to the voltage and current sensors respectively, is used to transform the three-phase current and three-phase voltage during motor operation to the γ1-δ1 and γ2-δ2 coordinate systems, respectively, to obtain the voltage signal u with disturbance in each coordinate system. γi and u δi and the voltage signal u γi and u δi The current signal i generated by the excitation γi and i δi Both the γ1-δ1 and γ2-δ2 coordinate systems have the same synchronous rotational speed as the dq rotating coordinate system, and each has an angular difference θ from the dq rotating coordinate system. γ1d and θ γ1d +ε,θ γ1d The position observation error is due to parameter error, ε is a preset angle, ε≠0; optionally, in this embodiment, ε=45°;

[0139] A bandpass filter, connected to the coordinate transformation module, is used to filter out u. γi u δi i γi and i δi The intermediate frequency is not equal to ω h The components are used to obtain the small signal voltage u. γih and u δih And in small signal voltage u γih and u δih Small signal current i under excitation γih and i δih ;

[0140] The incremental inductance calculation unit, connected to a bandpass filter, is used to utilize the small-signal voltage u. γih and u δih Small signal current i γih and i δih Calculate the incremental inductance observed in the γ1-δ1 and γ2-δ2 coordinate systems respectively. and

[0141] And a parameter error compensation unit, connected to the observation increment inductance calculation unit, used to calculate according to... Calculate the position observation error θ caused by parameter errors. γ1d And provide compensation;

[0142] Where i = 1 or 2; when i = 1, u γi u δi i γi i δi u γih u δih i γihand i δih Both are signals in the γ1-δ1 coordinate system; when i=2, u γi u δi i γi i δi u γih u δih i γih and i δih All signals are in the γ2-δ2 coordinate system; To observe the incremental inductance, let represent the derivative of the flux linkage along the x-axis with respect to the current along the y-axis in the same coordinate system.

[0143] To further improve the accuracy and dynamics of rotor positionless control, this embodiment also includes: a dynamic compensation module, used to... Calculate and compensate for the position observation error Δθ caused by magnetic flux nonlinearity;

[0144] Among them, R s Indicates motor resistance; u d and u q These represent the d-axis voltage and the q-axis voltage, respectively; i d and i q These represent the d-axis current and the q-axis current, respectively. and Representing i respectively d and i q The derivative of ψ d and ψ q These represent the d-axis flux linkage and the q-axis flux linkage, respectively. Let q be the apparent inductance along the q-axis, and let q be the flux linkage generated by current excitation along the q-axis divided by the current along the q-axis.

[0145] In this embodiment, the specific implementation methods of each module can be referred to the description in Embodiment 1 above, and will not be repeated here.

[0146] Example 3:

[0147] A synchronous motor system without position control, comprising:

[0148] Synchronous motor;

[0149] A position observer is connected to the synchronous motor and is used to obtain the rotor position observation value of the synchronous motor; in this embodiment, the model of the position observer is as shown in formula (1);

[0150] The position compensation device for a synchronous motor without position control provided in Embodiment 1 above is connected to both the synchronous motor and the position observer, and is used to calculate and compensate for the error in the rotor position observation value.

[0151] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A position compensation method for a synchronous motor without position control, characterized in that, include: Disturbance injection steps: During motor operation, inject a frequency of ω into the command voltages of its d and q axes respectively. h The disturbance voltage; ω h ≠6nω e ω e This represents the fundamental frequency of the motor, where n is a positive integer; The parameter error compensation steps include: (S1) Collect the three-phase current and three-phase voltage under the motor's operating state, and transform them to the γ1-δ1 coordinate system and the γ2-δ2 coordinate system respectively to obtain the voltage signal u with disturbance in each coordinate system. γi and u δi and the voltage signal u γi and u δi The current signal i generated by the excitation γi and i δi ; Both the γ1-δ1 and γ2-δ2 coordinate systems have the same synchronous rotational speed as the dq rotating coordinate system, and each has an angular difference θ from the dq rotating coordinate system. γ1d and θ γ1d +ε,θ γ1d The position observation error is due to parameter error, ε is the preset angle, and ε≠0; (S2) Filter out u γi u δi i γi and i δi The intermediate frequency is not equal to ω h The components are used to obtain the small signal voltage u. γih and u δih And in small signal voltage u γih and u δih Small signal current i under excitation γih and i δih ; (S3) Utilizing small signal voltage u γih and u δih Small signal current i γih and i δih Calculate the incremental inductance observed in the γ1-δ1 and γ2-δ2 coordinate systems respectively. and (S4) According to Calculate the position observation error θ caused by parameter errors. γ1d And provide compensation; Where i = 1 or 2; when i = 1, u γi u δi i γi i δi u γih u δih i γih and i δih All signals are in the γ1-δ1 coordinate system; when i=2, u γi u δi i γi i δi u γih u δih i γih and i δih All signals are in the γ2-δ2 coordinate system; To observe the incremental inductance, let represent the derivative of the flux linkage along the x-axis with respect to the current along the y-axis in the same coordinate system.

2. The position compensation method for a synchronous motor without position control as described in claim 1, characterized in that, ε = 45°.

3. The position compensation method for a synchronous motor without position control as described in claim 1 or 2, characterized in that, The step (S3) further includes: using a small signal voltage u γih and u δih Small signal current i γih and i δih Calculate the motor winding R s ; Furthermore, a dynamic compensation step is included after the parameter error compensation step. The dynamic compensation step includes: according to Calculate and compensate for the position observation error Δθ caused by magnetic flux nonlinearity; Among them, u d and u q These represent the d-axis voltage and the q-axis voltage, respectively; i d and i q These represent the d-axis current and the q-axis current, respectively. and Representing i respectively d and i q The derivative of ψ d and ψ q These represent the d-axis flux linkage and the q-axis flux linkage, respectively. Let q be the apparent inductance along the q-axis, and let q be the flux linkage generated by current excitation along the q-axis divided by the current along the q-axis.

4. A position compensation device for a synchronous motor without position control, characterized in that, include: Disturbance injection module and parameter error compensation module; The disturbance injection module is used to inject a frequency of ω into the d-axis and q-axis command voltages of the motor during operation. h The disturbance voltage; ω h ≠6nω e ω e This represents the fundamental frequency of the motor, where n is a positive integer; The parameter error compensation module includes: A voltage sensor, connected to the synchronous motor, is used to collect the three-phase voltage during motor operation; A current sensor, connected to the synchronous motor, is used to collect the three-phase current during motor operation. The coordinate transformation module, connected to the voltage sensor and the current sensor respectively, is used to transform the three-phase current and three-phase voltage during motor operation to the γ1-δ1 coordinate system and the γ2-δ2 coordinate system respectively, to obtain the voltage signal u with disturbance in each coordinate system. γi and u δi and the voltage signal u γi and u δi The current signal i generated by the excitation γi and i δi Both the γ1-δ1 and γ2-δ2 coordinate systems have the same synchronous rotational speed as the dq rotating coordinate system, and each has an angular difference θ from the dq rotating coordinate system. γ1d and θ γ1d +ε,θ γ1d The position observation error is due to parameter error, ε is the preset angle, and ε≠0; A bandpass filter, connected to the coordinate transformation module, is used to filter out u. γi u δi i γi and i δi The intermediate frequency is not equal to ω h The components are used to obtain the small signal voltage u. γih and u δih And in small signal voltage u γih and u δih Small signal current i under excitation γih and i δih ; The observation incremental inductance calculation unit, connected to the bandpass filter, is used to utilize the small-signal voltage u γih and u δih Small signal current i γih and i δih Calculate the incremental inductance observed in the γ1-δ1 and γ2-δ2 coordinate systems respectively. and And a parameter error compensation unit, connected to the observation increment inductance calculation unit, for use in accordance with... Calculate the position observation error θ caused by parameter errors. γ1d And provide compensation; Where i = 1 or 2; when i = 1, u γi u δi i γi i δi u γih u δih i γih and i δih Both are signals in the γ1-δ1 coordinate system; when i=2, u γi u δi i γi i δi u γih u δih i γih and i δih All signals are in the γ2-δ2 coordinate system; To observe the incremental inductance, let represent the derivative of the flux linkage along the x-axis with respect to the current along the y-axis in the same coordinate system.

5. The position compensation device for a synchronous motor without position control as described in claim 4, characterized in that, ε = 45°.

6. The position compensation device for a synchronous motor without position control as described in claim 4 or 5, characterized in that, The incremental inductance calculation unit is also used to utilize small-signal voltage u γih and u δih Small signal current i γih and i δih Calculate the motor winding R s ; Furthermore, the position compensation device for a synchronous motor without position control further includes: a dynamic compensation module, used to... Calculate and compensate for the position observation error Δθ caused by magnetic flux nonlinearity; Among them, u d and u q These represent the d-axis voltage and the q-axis voltage, respectively; i d and i q These represent the d-axis current and the q-axis current, respectively. and Representing i respectively d and i q The derivative of ψ d and ψ q These represent the d-axis flux linkage and the q-axis flux linkage, respectively. Let q be the apparent inductance along the q-axis, and let q be the flux linkage generated by current excitation along the q-axis divided by the current along the q-axis.

7. A synchronous motor system without position control, characterized in that, include: Synchronous motor; A position observer, connected to the synchronous motor, is used to obtain the rotor position observation value of the synchronous motor; And the position compensation device for a synchronous motor without position control as described in any one of claims 4 to 6, which is connected to both the synchronous motor and the position observer, and is used to calculate and compensate for the error in the rotor position observation value.

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