A construction method of a voltage type rotor flux observer based on orthogonal compensation

Abstract

The application provides a construction method of a voltage type rotor flux linkage observer based on orthogonal compensation, and the method comprises the following steps: constructing an initial voltage type rotor flux linkage observer based on alpha-beta phase voltage and current of an asynchronous motor, wherein the initial voltage type rotor flux linkage observer comprises a stator flux linkage and a leakage magnetic term; performing frequency domain conversion on the stator flux linkage, and calculating the corresponding relationship between the stator flux linkage after frequency domain conversion and the stator back electromotive force of the asynchronous motor; obtaining the direct current deviation of the asynchronous motor based on the corresponding relationship; calculating a direct current bias compensation amount based on the direct current deviation; obtaining a stator flux linkage model containing direct current bias compensation based on the direct current deviation and the direct current bias compensation amount; and constructing an improved voltage type rotor flux linkage observer based on orthogonal compensation based on the stator flux linkage model and the leakage magnetic term. The application constructs a stator flux linkage model containing direct current bias compensation, thereby constructing an improved voltage type rotor flux linkage observer based on orthogonal compensation, and further eliminating the influence of direct current bias.

Description

Technical Field

[0001] This invention relates to the field of power electronics technology, and more specifically, to a method for constructing a voltage-type rotor flux observer based on orthogonal compensation. Background Technology

[0002] The key to induction motor control systems is accurately obtaining the magnitude and spatial position of the rotor flux linkage vector. Direct detection of rotor flux linkage is difficult. Existing literature indicates that flux linkage estimation mostly employs voltage models, current models, and full-order flux linkage observation models. Since the current model includes the rotor time constant and mutual inductance parameters, these parameters are significantly affected by motor temperature rise and magnetic circuit saturation, leading to flux linkage observation errors. However, overall, the current model does not require a voltage signal and is unaffected by DC bias, making it more suitable for low-speed operation. The voltage model does not include rotor resistance, resulting in stronger robustness to motor parameters; therefore, it outperforms the current model at medium and high speeds.

[0003] However, the voltage model has two main problems in practical applications: first, it is sensitive to changes in stator resistance at low speeds; second, the pure integral element in the model is prone to causing flux linkage observation errors. The former can be mitigated by adaptive online parameter settings to reduce the influence of stator resistance parameters; however, in practical applications, the DC bias problem in the pure integral element is more pronounced due to electromagnetic interference, sensor measurement and sampling errors, etc. Therefore, how to further eliminate the influence of DC bias and establish a stable voltage-type rotor flux linkage observer is an urgent problem to be solved. Summary of the Invention

[0004] This invention addresses the technical problems existing in the prior art by providing a method for constructing a voltage-type rotor flux observer based on orthogonal compensation, thereby solving the problem of how to further eliminate the influence of DC bias and establish a stable voltage-type rotor flux observer.

[0005] A first aspect of the present invention provides a method for constructing a voltage-type rotor flux observer based on orthogonal compensation, comprising:

[0006] Based on the α-β phase voltage and current of the asynchronous motor, an initial voltage-type rotor flux linkage observer is constructed, which includes stator flux linkage and leakage flux term;

[0007] The stator flux linkage is frequency-domain converted, and the correspondence between the frequency-domain converted stator flux linkage and the stator back electromotive force of the asynchronous motor is calculated.

[0008] Based on the aforementioned correspondence, the DC deviation of the asynchronous motor is obtained;

[0009] Based on the DC deviation, calculate the DC bias compensation amount;

[0010] Based on the DC deviation and the DC bias compensation amount, a stator flux linkage model with DC bias compensation is obtained;

[0011] Based on the stator flux linkage model and the leakage flux term, an improved voltage-type rotor flux linkage observer based on orthogonal compensation is constructed.

[0012] Based on the above technical solution, the present invention can also be improved as follows.

[0013] Preferably, the stator magnetic flux linkage is characterized by... for:

[0014]

[0015] Where j is the imaginary unit, ω e For the synchronization angular frequency, u s R is the stator voltage. s For stator resistance, i s This is the stator current.

[0016] Preferably, the stator flux linkage after frequency domain conversion for:

[0017]

[0018] Among them, e s For the stator back electromotive force, S = jω e u s R is the stator voltage. s For stator resistance, i s This refers to the stator current.

[0019] Preferably, the correspondence is as follows:

[0020]

[0021] Where j is the imaginary unit, ω e e is the synchronization angular frequency. s For the stator back electromotive force, ω e The synchronization angular frequency, This refers to the stator flux linkage after frequency domain conversion.

[0022] Preferably, the DC deviation D of the asynchronous motor is:

[0023]

[0024] Where, ω e The synchronization angular frequency, e represents the stator flux linkage after frequency domain transformation. s is the stator back electromotive force, and j is the imaginary unit.

[0025] Preferably, the DC bias compensation amount for:

[0026]

[0027] Where, k p k i For PI parameters, S = jω e D is the DC deviation, ω e The synchronization angular frequency, e represents the stator flux linkage after frequency domain transformation. s is the stator back electromotive force, and j is the imaginary unit.

[0028] Preferably, the stator flux linkage model is as follows:

[0029]

[0030] in, For stator flux linkage, e is the DC bias compensation amount. s For the stator back electromotive force, k p k i For PI parameters, S = jω e D represents the DC deviation.

[0031] Preferably, the transfer function G(s) of the stator flux linkage model is:

[0032]

[0033] in, e represents the stator flux linkage after frequency domain transformation. s For the stator back electromotive force, S = jω e ω e k is the synchronization angular frequency. p k i Here, j represents the PI parameter, and j is the imaginary unit.

[0034] Preferably, the steady-state frequency response of the stator flux linkage model is:

[0035]

[0036] in, e represents the stator flux linkage after frequency domain transformation. s For the stator back electromotive force, ω e ω is the synchronization angular frequency, and j is the imaginary unit.

[0037] Preferably, the expression for the improved voltage-type rotor flux observer is:

[0038]

[0039] Where σ is the leakage inductance coefficient, L s For stator self-inductance, L r For rotor self-inductance, L m For mutual inductance, k p k i For PI parameters, u sa Let i be the stator voltage along the a-axis. sa R is the stator current along the a-axis. s For stator resistance, u sβ Let i be the stator voltage along the β axis. sβ Let ω be the stator current along the β axis. e The angular frequency is S = jω. e , where j is the imaginary unit.

[0040] This invention provides a method for constructing a voltage-type rotor flux linkage observer based on orthogonal compensation. The method includes: constructing an initial voltage-type rotor flux linkage observer based on the α-β phase voltage and current of an asynchronous motor, wherein the initial voltage-type rotor flux linkage observer includes stator flux linkage and leakage flux term; performing frequency domain transformation on the stator flux linkage and calculating the correspondence between the frequency-domain transformed stator flux linkage and the stator back electromotive force of the asynchronous motor; obtaining the DC deviation of the asynchronous motor based on the correspondence; calculating the DC bias compensation amount based on the DC deviation; obtaining a stator flux linkage model with DC bias compensation based on the DC deviation and the DC bias compensation amount; and constructing an improved voltage-type rotor flux linkage observer based on orthogonal compensation based on the stator flux linkage model and the leakage flux term. This invention further eliminates the influence of DC bias and establishes a stable voltage-type rotor flux linkage observer by constructing a stator flux linkage model with DC bias compensation and constructing an improved voltage-type rotor flux linkage observer based on orthogonal compensation. Attached Figure Description

[0041] Figure 1 A flowchart illustrating a method for constructing a voltage-type rotor flux observer based on orthogonal compensation, provided by this invention;

[0042] Figure 2 This is a basic implementation block diagram of a voltage-type rotor flux observer;

[0043] Figure 3 A block diagram illustrating the implementation of the improved voltage-type stator flux linkage model based on orthogonal compensation provided by this invention;

[0044] Figure 4 A block diagram illustrating the implementation of the improved voltage rotor flux observer based on orthogonal compensation provided by this invention;

[0045] Figure 5This is a schematic diagram comparing the effects of various flux observers under DC bias conditions provided by the present invention.

[0046] Figure 6 A schematic diagram illustrating the effect of the improved voltage-type rotor flux observer under the condition of sudden velocity change provided by the present invention;

[0047] Figure 7 A schematic diagram of the improved voltage-type rotor observer under sudden load torque changes provided by the present invention. Detailed Implementation

[0048] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0049] Figure 1 A flowchart illustrating a method for constructing a voltage-type rotor flux observer based on orthogonal compensation, as provided by this invention, is shown below. Figure 1 As shown, the method includes:

[0050] Step S100: Based on the α-β phase voltage and current of the asynchronous motor, construct an initial voltage-type rotor flux linkage observer, which includes stator flux linkage and leakage flux term;

[0051] It is understandable that the implementation block diagram of the above initial voltage-type rotor flux observer can be found in [reference needed]. Figure 2 , Figure 2 The diagram shows the basic implementation block diagram of the voltage-type rotor flux linkage observer. Based on the mathematical model of the asynchronous motor, the expression for the voltage rotor flux linkage equation in the α-β coordinate system can be obtained from the flux linkage equation:

[0052]

[0053] From the voltage equation, we can obtain:

[0054]

[0055] Combining the above two equations, we can simplify to obtain the expression for the voltage-type rotor flux observer:

[0056]

[0057] Therefore, the initial voltage-type rotor flux observer does not contain rotational speed information. The rotor flux can be considered as having stator flux. and leakage magnetic term σL s i sThe stator flux linkage is composed of components that are purely integral. Under the influence of DC bias, flux linkage observation divergence is inevitable, leading to instability of the reference model and the inability to estimate the rotational speed. Therefore, corrective measures must be taken.

[0058] Common improved voltage-mode rotor flux observers are mainly based on first-order low-pass filters. This method uses a first-order low-pass filter to replace the pure integrator, thus avoiding the influence of DC bias. However, while the improved voltage-mode rotor flux observer based on the first-order low-pass filter avoids the presence of pure integrators and can somewhat eliminate the influence of DC bias, the presence of the first-order low-pass filter still causes a phase shift in the observed flux, which still has a significant impact on the stability of the model.

[0059] To avoid the phase shift issues that occur in flux observations caused by the characteristics of the first-order low-pass filter in the improved voltage-type rotor flux observer, an improved voltage-type rotor flux observer based on orthogonal compensation is proposed to obtain a more stable speed estimation reference model.

[0060] Step S200: Perform frequency domain conversion on the stator flux linkage and calculate the correspondence between the frequency domain converted stator flux linkage and the stator back electromotive force of the asynchronous motor;

[0061] If we use frequency to represent the stator flux linkage in a voltage-type rotor flux linkage observer, then the stator flux linkage... for:

[0062]

[0063] Where j is the imaginary unit, ω e For the synchronization angular frequency, u s R is the stator voltage. s For stator resistance, i s This refers to the stator current.

[0064] Transform formula (3) into an expression in the frequency domain:

[0065]

[0066] Among them, e s For the stator back electromotive force, S = jω e u s R is the stator voltage. s For stator resistance, i s This refers to the stator current.

[0067] From formula (3), it can be seen that for the integral element, under ideal steady-state conditions, its stator flux linkage and back electromotive force satisfy the following relationship:

[0068]

[0069] Where j is the imaginary unit, ω e e is the synchronization angular frequency. s For the stator back electromotive force, ω e The synchronization angular frequency, This refers to the stator flux linkage after frequency domain conversion.

[0070] Step S300: Based on the correspondence, obtain the DC deviation of the asynchronous motor;

[0071] Furthermore, the DC deviation D mentioned above is defined as:

[0072]

[0073] Where, ω e The synchronization angular frequency, e represents the stator flux linkage after frequency domain transformation. s is the stator back electromotive force, and j is the imaginary unit.

[0074] Step S400: Calculate the DC bias compensation amount based on the DC deviation;

[0075] Furthermore, DC bias compensation amount for

[0076]

[0077] Where, k p k i For PI parameters, S = jω e D is the DC deviation, ω e The synchronization angular frequency, e represents the stator flux linkage after frequency domain transformation. s is the stator back electromotive force, and j is the imaginary unit.

[0078] Step S500: Based on the DC deviation and the DC bias compensation amount, obtain the stator flux linkage model with DC bias compensation;

[0079] Furthermore, the above stator flux linkage model is as follows:

[0080]

[0081] in, For stator flux linkage, e is the DC bias compensation amount. s For the stator back electromotive force, k p k i For PI parameters, S = jω e D represents the DC deviation.

[0082] Furthermore, the implementation block diagram of the above stator flux linkage model can be found in [link to block diagram]. Figure 3 The transfer function G(s) of the above stator flux linkage model is:

[0083]

[0084] in, e represents the stator flux linkage after frequency domain transformation. s For the stator back electromotive force, S = jω e ω e k is the synchronization angular frequency. p k i Here, j represents the PI parameter, and j is the imaginary unit.

[0085] Furthermore, the steady-state frequency response of the above stator flux linkage model is:

[0086]

[0087] in, e represents the stator flux linkage after frequency domain transformation. s For the stator back electromotive force, ω e ω is the synchronization angular frequency, and j is the imaginary unit.

[0088] Step S600: Based on the stator flux linkage model and the leakage flux term, construct an improved voltage-type rotor flux linkage observer based on orthogonal compensation.

[0089] Furthermore, the expression for the improved voltage-type rotor flux observer is as follows:

[0090]

[0091] Where σ is the leakage inductance coefficient, L s For stator self-inductance, L r For rotor self-inductance, L m For mutual inductance, k p k i For PI parameters, u sa Let i be the stator voltage along the a-axis. sa R is the stator current along the a-axis. s For stator resistance, u sβ Let i be the stator voltage along the β axis. sβ Let ω be the stator current along the β axis. e The angular frequency is S = jω. e , where j is the imaginary unit.

[0092] Furthermore, considering the elimination of integral saturation, a block diagram of an improved voltage-type rotor flux observer based on orthogonal compensation can be obtained, see [link to block diagram]. Figure 4.

[0093] Furthermore, to verify the effectiveness of the improved voltage-type rotor flux observer based on orthogonal compensation, a simulation model of the rotor flux observer was built in MATLAB / Simulink, and relevant simulation verification was performed. The simulation model mainly consists of a flux observer module, a simulated real flux extraction module, and a stator frequency calculation module.

[0094] Simulations were performed on a voltage-source rotor flux observer, an improved voltage-source rotor flux observer based on a first-order low-pass filter, and an improved voltage-source rotor flux observer based on orthogonal compensation under DC bias conditions. The commanded speed was set to 200 r / min, the load torque to 0 Nm, and the DC bias to be applied to the α-phase current at a magnitude of 0.2 A. All relevant parameters were set to their actual values. Simultaneously, the output of the asynchronous motor's rotor flux module was extracted from MATLAB / Simulink and used as the actual flux value for reference. The simulation results are shown in [link to simulation results]. Figure 5 .

[0095] Depend on Figure 5 Simulation results show that, in the presence of DC bias: due to its pure integral nature, the DC bias of the voltage-type rotor flux observer will continuously accumulate, resulting in a significant error compared to the actual flux; the improved voltage-type rotor flux observer based on a first-order low-pass filter can eliminate the influence of DC bias to some extent, but phase and amplitude deviations still exist; the improved voltage-type rotor flux observer based on quadrature compensation achieves the best DC bias elimination results and has no phase effect. Therefore, the improved voltage-type flux observer based on quadrature compensation in this embodiment can effectively eliminate DC bias.

[0096] Furthermore, simulations were conducted to examine the flux linkage observation effect under sudden speed changes. The initial speed was 200 r / min, the sudden speed change was 400 r / min, and the final speed was 200 r / min. The DC bias was set to the α-phase current with a magnitude of 0.2 A. Simultaneously, the output of the rotor flux linkage module of the asynchronous motor was extracted as the actual flux linkage value for reference. The simulation results are shown in [link to simulation results]. Figure 6 .

[0097] Depend on Figure 6 It can be seen that the improved voltage-type rotor flux linkage observer based on orthogonal compensation can effectively observe the rotor flux linkage even under sudden speed changes. Only during sudden speed changes do the observed values ​​fluctuate slightly, but they quickly track the actual flux linkage, enabling effective tracking and observation of the rotor flux linkage.

[0098] Furthermore, a simulation of the flux linkage effect under sudden load torque changes was conducted. The rotational speed was set to 200 r / min, the initial load torque was set to 0 N / m, the load torque suddenly increased to 5 N / m at 1 s, and the final torque was 0 N / m. The DC bias was set to the α-phase current with a magnitude of 0.2 A. Simultaneously, the output of the rotor flux linkage module of the asynchronous motor was extracted as the actual flux linkage value for reference. The simulation results can be found in [link to simulation results]. Figure 7 .

[0099] Depend on Figure 7 It can be seen that the improved voltage-type rotor flux linkage observer based on orthogonal compensation can effectively observe the rotor flux linkage even under sudden speed changes. Only during sudden torque changes do the observed values ​​fluctuate slightly, but they can quickly track the actual flux linkage, enabling effective tracking and observation of the rotor flux linkage.

[0100] Therefore, it can be seen that the improved voltage-type rotor flux linkage observer based on orthogonal compensation in this embodiment can achieve good flux linkage observation under various operating conditions, even in the presence of DC bias, proving the effectiveness of the improved voltage-type rotor flux linkage observer based on orthogonal compensation provided in this embodiment.

[0101] Understandably, given the deficiencies in the background technology, this invention proposes a method for constructing a voltage-type rotor flux linkage observer based on orthogonal compensation. The method includes: constructing an initial voltage-type rotor flux linkage observer based on the α-β phase voltage and current of an asynchronous motor, wherein the initial voltage-type rotor flux linkage observer includes stator flux linkage and leakage flux terms; performing frequency domain transformation on the stator flux linkage, and calculating the correspondence between the frequency-domain transformed stator flux linkage and the stator back electromotive force of the asynchronous motor; obtaining the DC deviation of the asynchronous motor based on the correspondence; calculating the DC bias compensation amount based on the DC deviation; obtaining a stator flux linkage model with DC bias compensation based on the DC deviation and the DC bias compensation amount; and constructing an improved voltage-type rotor flux linkage observer based on orthogonal compensation based on the stator flux linkage model and the leakage flux terms. This invention further eliminates the influence of DC bias and establishes a stable voltage-type rotor flux linkage observer by constructing a stator flux linkage model with DC bias compensation and constructing an improved voltage-type rotor flux linkage observer based on orthogonal compensation.

[0102] It should be noted that the descriptions of each embodiment in the above embodiments have different focuses. For parts that are not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0103] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0104] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0105] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0106] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0107] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0108] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A method for constructing a voltage-type rotor flux observer based on orthogonal compensation, characterized in that, The method includes: Based on the α-β phase voltage and current of the asynchronous motor, an initial voltage-type rotor flux linkage observer is constructed, which includes stator flux linkage and leakage flux term; The stator flux linkage is frequency-domain converted, and the correspondence between the frequency-domain converted stator flux linkage and the stator back electromotive force of the asynchronous motor is calculated. The stator flux linkage after frequency domain conversion for: ； in, e s The stator back electromotive force, S = , u s Stator voltage, R s For stator resistance, i s Stator current; Based on the aforementioned correspondence, the DC deviation of the asynchronous motor is obtained; Based on the DC deviation, calculate the DC bias compensation amount; The DC bias compensation amount for: ； in, k p , k i For PI parameters, S = , D For DC deviation, The synchronization angular frequency, The stator flux linkage after frequency domain conversion. e s The stator back electromotive force, j The imaginary unit; Based on the DC deviation and the DC bias compensation amount, a stator flux linkage model with DC bias compensation is obtained; Based on the stator flux linkage model and the leakage flux term, an improved voltage-type rotor flux linkage observer based on orthogonal compensation is constructed. The expression for the improved voltage-type rotor flux observer is: ； Where σ is the leakage inductance coefficient, L s For the self-sensing of the stator, L r For rotor self-inductance, L m For mutual intuition, k p , k i For PI parameters, u sa for a Stator voltage of the shaft, i sa for a Stator current of the shaft, R s For stator resistance, u sβ for β Stator voltage of the shaft, i sβ for β Stator current of the shaft, For the synchronization angular frequency, S = , j It is the imaginary unit.

2. The method for constructing a voltage-type rotor flux observer based on orthogonal compensation according to claim 1, characterized in that, The stator magnetic flux for: ； in, j The imaginary unit, The synchronization angular frequency, u s Stator voltage, R s For stator resistance, i s This refers to the stator current.

3. The method for constructing a voltage-type rotor flux observer based on orthogonal compensation according to claim 1, characterized in that, The correspondence is as follows: ； in, j The imaginary unit, The synchronization angular frequency, e s The stator back electromotive force, The synchronization angular frequency, This refers to the stator flux linkage after frequency domain conversion.

4. The method for constructing a voltage-type rotor flux observer based on orthogonal compensation according to claim 1, characterized in that, DC deviation of the asynchronous motor D for: ； in, The synchronization angular frequency, The stator flux linkage after frequency domain conversion. e s The stator back electromotive force, j It is the imaginary unit.

5. The method for constructing a voltage-type rotor flux observer based on orthogonal compensation according to claim 1, characterized in that, The stator flux linkage model is as follows: ； in, For stator flux linkage, This is the DC bias compensation amount. e s The stator back electromotive force, k p , k i For PI parameters, S = , D This represents DC deviation.

6. The method for constructing a voltage-type rotor flux observer based on orthogonal compensation according to claim 1, characterized in that, The transfer function of the stator flux linkage model for: ； in, The stator flux linkage after frequency domain conversion. e s The stator back electromotive force, S = , The synchronization angular frequency, k p , k i For PI parameters, j It is the imaginary unit.

7. The method for constructing a voltage-type rotor flux observer based on orthogonal compensation according to claim 1, characterized in that, The steady-state frequency response of the stator flux linkage model is: ； in, The stator flux linkage after frequency domain conversion. e s The stator back electromotive force, The synchronization angular frequency, j It is the imaginary unit.

Images