Permanent magnet synchronous motor minimum loss control method and device based on vector magnetic circuit law

Abstract

The application discloses a minimum loss control method and device of a permanent magnet synchronous motor based on a vector magnetic circuit law. The method comprises the following steps: an accurate dynamic model of the permanent magnet synchronous motor considering core loss is established; a loss equation of the permanent magnet synchronous motor under the condition of considering core loss is obtained from the model, and then the loss equation is combined with a torque constraint condition to form a loss criterion F which can reflect the loss of the permanent magnet synchronous motor; the d and q axis current reference values are obtained by solving the loss criterion F through the Lagrange multiplier method; then the d and q axis current reference values are input into a proportional integral (PI) controller to output reference voltage by adjusting the error between the actual current and the reference current; the output reference voltage is processed through coordinate transformation and space vector pulse width modulation algorithm in sequence to generate six-way switching signal of an inverter to control the inverter, and then the permanent magnet synchronous motor is driven to work normally through the inverter, so that the minimum loss control of the closed loop feedback of the permanent magnet synchronous motor is realized.

Description

Technical Field

[0001] This invention relates to the field of motor loss control technology, specifically to a method and device for minimum loss control of a permanent magnet synchronous motor based on the vector magnetic circuit law. Background Technology

[0002] Permanent magnet synchronous motors (PMSMs) play a vital role in industry due to their significant advantages such as high efficiency, high power density, and excellent speed regulation performance, and are widely used in industrial automation, new energy vehicles, and rail transportation. However, core losses often occur during the operation of PMSMs. During motor operation, a portion of the input electrical energy is converted into heat energy and dissipated as core loss, rather than being effectively converted into mechanical energy output, resulting in a relative reduction in the motor's output power and affecting its energy utilization efficiency. Core losses include hysteresis losses and eddy current losses, both of which are related to motor speed, effective voltage, and magnetic flux density, and their variation under different motor operating conditions (such as high-speed operation and different load conditions) is quite complex. Typically, to simplify the mathematical model of PMSMs, the existence of core losses is ignored.

[0003] Because mathematical models that neglect core losses cannot fully reflect the actual operating conditions of motors, control strategies derived from them will inevitably have limitations in practical applications. Therefore, motor control technology is developing towards greater precision, efficiency, and reliability, paying increasing attention to various practical factors in motor operation (such as core losses, inverter losses, and harmonic effects), and continuously optimizing control strategies to improve the overall performance of motors.

[0004] Traditional control methods that ignore core losses rely on mathematical models that fail to reflect this actual influencing factor, thus failing to fully represent the actual operating conditions of the motor. Control strategies derived from such models have limitations, resulting in low control accuracy and failing to meet the demands for high-performance motor control. Fuzzy control-based permanent magnet synchronous motor control methods do not directly model and calculate core losses precisely. They typically monitor the overall motor operating status and adjust accordingly based on fuzzy rules, indirectly addressing operating conditions potentially affected by core losses. However, this method lacks quantitative analysis and precise control of core losses, thus limiting the stability and consistency of its control performance.

[0005] Therefore, there is an urgent need to propose a minimum loss control method for permanent magnet synchronous motors to achieve high-quality control of permanent magnet synchronous motors while considering core losses. Summary of the Invention

[0006] The purpose of this invention is to provide a method and apparatus for minimum loss control of permanent magnet synchronous motors (PMSMs) based on the vector magnetic circuit law. This addresses the problem that the presence of core losses is often overlooked in the modeling and control of PMSMs, thus affecting the accuracy of motor control. This invention proposes a minimum loss control method for PMSMs that performs minimum loss control of the PMSM under precise modeling considering core losses, achieving high-quality control of the PMSM.

[0007] To achieve the above objectives, the embodiments of the present invention provide the following technical solutions:

[0008] In a first aspect, the present invention provides a method for minimum loss control of a permanent magnet synchronous motor based on the vector magnetic circuit law, the method comprising:

[0009] An accurate dynamic model of a permanent magnet synchronous motor considering core losses is constructed based on the vector magnetic circuit law.

[0010] Based on the accurate dynamic model of permanent magnet synchronous motor considering core losses, a criterion that can reflect the losses of permanent magnet synchronous motor is derived.

[0011] The loss criteria reflecting the losses of permanent magnet synchronous motors are solved using the Lagrange multiplier method to obtain the reference values ​​of d-axis and q-axis currents;

[0012] The error between the actual current and the reference current is adjusted according to the d-axis and q-axis current reference values, thereby outputting a reference voltage;

[0013] The output reference voltage is processed sequentially through coordinate transformation and space vector pulse width modulation algorithm to generate six switching signals for the inverter, thereby controlling the inverter and achieving closed-loop feedback with minimum loss control of the permanent magnet synchronous motor.

[0014] In one implementation, the construction of an accurate dynamic model of the permanent magnet synchronous motor considering core losses based on the vector magnetic circuit law includes:

[0015] Construct the magnetomotive force equation of a permanent magnet synchronous motor considering core losses;

[0016] Substituting the equivalent magnetic induction and magnetocapacitance parameters into the magnetomotive force equation of the permanent magnet synchronous motor considering core losses, based on the vector magnetic circuit law, we obtain the magnetomotive force equation of the permanent magnet synchronous motor considering core losses.

[0017] The stator flux linkage equation is derived from the magnetomotive force equation of a permanent magnet synchronous motor considering core losses, based on the vector magnetic circuit law.

[0018] The dynamic voltage equations of the permanent magnet synchronous motor are listed, and the stator flux linkage equations are substituted into the motor voltage dynamic equations to obtain an accurate dynamic model of the permanent magnet synchronous motor considering core losses.

[0019] In one embodiment, deriving the stator flux linkage equation based on the magnetomotive force equation of a permanent magnet synchronous motor considering core losses according to the vector magnetic circuit law includes:

[0020] The magnetomotive force equation based on the vector magnetic circuit law considering core loss is transformed by coordinate transformation to obtain the expression of magnetomotive force in the dq coordinate system;

[0021] Based on the magnetomotive force calculation formula of permanent magnet synchronous motor, the relationship satisfied by the magnetomotive force is derived;

[0022] The magnetic flux on the d and q axes can be derived from the expression of the magnetomotive force in the dq coordinate system and the relation it satisfies.

[0023] The stator flux linkage equation is derived from the relationship between flux linkage and magnetic flux.

[0024] In one embodiment, the magnetomotive force equation of the permanent magnet synchronous motor based on the vector magnetic circuit law, considering core losses, is as follows:

[0025]

[0026] in, This represents the magnetomotive force of phases a, b, and c. Φ represents the magnetic reluctance along each axis in the coordinate system a, b, and c. abc Represent the magnetic flux of phases a, b, and c, and define the iron loss coefficient. Based on the vector magnetic circuit law, magnetic induction and virtual magnetic capacitance are represented respectively, I 3×3 Let p denote the third-order identity matrix, and let p denote the differential operator, which means differentiating over time.

[0027] In one embodiment, the stator flux linkage equation is:

[0028]

[0029] Where, ψ f Indicates permanent magnet flux linkage. This represents a coefficient defined for ease of simplification.

[0030] In one embodiment, the accurate dynamic model of the permanent magnet synchronous motor considering core losses is as follows:

[0031]

[0032] Among them, u d u q R represents the voltage on the d and q axes. s ω represents the stator resistance of the permanent magnet synchronous motor, i represents the angular velocity of the motor, and i represents the angular velocity of the motor. d i qLet L1 and L2 represent the current components on the d and q axes, respectively, and let L1 and L2 represent the inductance parameters considering core losses, respectively. f1 ψ f2 These represent the magnetic flux components of the permanent magnet.

[0033] In one implementation, the step of deriving a criterion reflecting the losses of a permanent magnet synchronous motor based on a precise dynamic model of the permanent magnet synchronous motor that considers core losses includes:

[0034] By using an accurate dynamic model of the permanent magnet synchronous motor considering core losses, the loss equation and electromagnetic torque equation of the permanent magnet synchronous motor are derived.

[0035] Construct a Lagrangian function based on the loss equation and electromagnetic torque equation of a permanent magnet synchronous motor;

[0036] Electromagnetic torque constraint conditions are constructed based on the torque accuracy requirements of permanent magnet synchronous motor control.

[0037] The Lagrange function, combined with torque constraints, forms a criterion that reflects the losses of a permanent magnet synchronous motor.

[0038] In one embodiment, the loss criterion for the permanent magnet synchronous motor is:

[0039]

[0040] Among them, T emref P represents the reference value of the electromagnetic torque of a permanent magnet synchronous motor. loss For permanent magnet synchronous motor losses, δ represents the Lagrange multiplier, and n p i represents the number of magnetic pole pairs. d i q Let L1 and L2 represent the current components on the d and q axes, respectively, and let L1 and L2 represent the inductance parameters considering core losses, respectively. f1 ψ f2 These represent the magnetic flux components of the permanent magnet.

[0041] Secondly, the present invention provides a minimum loss control device for a permanent magnet synchronous motor based on the vector magnetic circuit law, the device comprising:

[0042] The precise dynamic model module is used to construct a precise dynamic model of a permanent magnet synchronous motor that takes into account core losses, based on the vector magnetic circuit law.

[0043] The loss criterion module is used to derive criteria that reflect the losses of permanent magnet synchronous motors based on an accurate dynamic model that takes into account the core losses of the permanent magnet synchronous motor.

[0044] The current reference value calculation module is used to solve the loss criteria reflecting the loss of the permanent magnet synchronous motor using the Lagrange multiplier method to obtain the d-axis and q-axis current reference values;

[0045] The reference voltage output module is used to adjust the error between the actual current and the reference current based on the d-axis and q-axis current reference values, thereby outputting a reference voltage.

[0046] The switching signal generation module is used to generate six switching signals for the inverter by processing the output reference voltage through coordinate transformation and space vector pulse width modulation algorithm, thereby controlling the inverter and realizing the minimum loss control of the closed-loop feedback of the permanent magnet synchronous motor.

[0047] Thirdly, the present invention provides a permanent magnet synchronous motor control system, the system including the aforementioned permanent magnet synchronous motor minimum loss control device based on the vector magnetic circuit law.

[0048] Fourthly, this invention provides a computer-readable storage medium storing computer program instructions that, when executed by a processor, implement the aforementioned method for minimum loss control of a permanent magnet synchronous motor based on the vector magnetic circuit law.

[0049] The technical solutions provided in this application embodiment may include the following beneficial effects:

[0050] This invention, based on precise modeling using the vector magnetic circuit law, provides a more accurate description of the motor's actual operation, laying a solid foundation for subsequent control strategies and enabling more precise control. By solving the loss criterion using the Lagrange multiplier method, reference values ​​for the d-axis and q-axis currents are obtained. The error between the actual current and the reference current is then adjusted to output a reference voltage, ultimately controlling the inverter to achieve minimum loss control through closed-loop feedback of the motor. This process comprehensively considers and accurately calculates core losses from a theoretical perspective, enabling targeted adjustments to motor operating parameters, effectively reducing various losses, including core losses, and improving the overall performance of the motor. Attached Figure Description

[0051] The accompanying drawings, as part of this invention, are provided to further illustrate the invention. The illustrative embodiments and descriptions of the invention are used to explain the invention, but do not constitute an undue limitation thereof. Clearly, the drawings described below are merely some embodiments, and those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0052] Figure 1 A flowchart of a method for minimum loss control of a permanent magnet synchronous motor based on the vector magnetic circuit law is provided in an embodiment of the present invention.

[0053] Figure 2 This is a block diagram of a permanent magnet synchronous motor control system provided in an embodiment of the present invention;

[0054] Figure 3This invention represents two control methods for a permanent magnet synchronous motor under different torques at a speed of 2000 r / min (the method described in this invention and i). d Efficiency comparison chart of the =0 method.

[0055] It should be noted that these accompanying drawings and textual descriptions are not intended to limit the scope of the invention in any way, but rather to illustrate the concept of the invention to those skilled in the art by referring to specific embodiments. Detailed Implementation

[0056] To enhance understanding of the present invention, the technical solution of the present invention will be further described below in conjunction with the accompanying drawings and specific embodiments. The following embodiments are explanations of the present invention, but the present invention is not limited to the following embodiments.

[0057] It should be understood that the described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0058] Reference Figure 1 As shown in the figure, this invention provides a method for minimum loss control of a permanent magnet synchronous motor based on the vector magnetic circuit law. The method includes the following steps:

[0059] Step S100: Construct an accurate dynamic model of the permanent magnet synchronous motor considering core losses based on the vector magnetic circuit law.

[0060] In this embodiment of the application, an accurate dynamic model of a permanent magnet synchronous motor considering core losses is constructed based on the vector magnetic circuit law, including:

[0061] Step S110: Construct the magnetomotive force equation of the permanent magnet synchronous motor considering core losses.

[0062] The magnetomotive force equation of a permanent magnet synchronous motor considering core losses is expressed as follows:

[0063]

[0064] in, This represents the magnetomotive force of phases a, b, and c. Φ represents the magnetic reluctance along each axis in the coordinate system a, b, and c. abc Indicates the magnetic flux of phases a, b, and c. Magnetic induction and virtual magnetocapacitance are represented according to the vector magnetic circuit law. Magnetic reluctance reflects the degree to which the magnetic circuit material and geometry impede magnetic flux; magnetic induction quantitatively reflects the impediment of the magnetic field in the magnetic circuit by the induced current generated by the magnetic flux in an equivalent closed loop; virtual magnetocapacitance can represent the hysteresis effect of magnetic materials under alternating magnetic flux. 3×3Let p denote the third-order identity matrix, and let p denote the differential operator, which means differentiating over time.

[0065] Step S120: Substitute the equivalent magnetic induction and magnetocapacitance parameters defined by the vector magnetic circuit law into the magnetomotive force equation of the permanent magnet synchronous motor considering core losses, and obtain the magnetomotive force equation of the permanent magnet synchronous motor considering core losses based on the vector magnetic circuit law.

[0066] A permanent magnet synchronous motor receives a three-phase sinusoidal current as input, thus generating a three-phase sinusoidal magnetic flux inside the motor. There exists a relationship between the integral and the derivative of a sinusoidal quantity. The numerical relationship is then used to define the iron loss coefficient. Substituting this into equation (1) simplifies the magnetomotive force equation, as shown below:

[0067]

[0068] Equation (2) is the magnetomotive force equation of the permanent magnet synchronous motor based on the vector magnetic circuit law and considering the iron core loss.

[0069] Step S130: Derive the stator flux linkage equation based on the magnetomotive force equation of the permanent magnet synchronous motor considering core losses according to the vector magnetic circuit law.

[0070] In this embodiment of the application, the stator flux linkage equation is derived from the magnetomotive force equation of a permanent magnet synchronous motor considering core losses based on the vector magnetic circuit law, including:

[0071] Step S131: Transform the magnetomotive force equation based on the vector magnetic circuit law and considering core loss to obtain the expression of the magnetomotive force in the dq coordinate system.

[0072] Equation (2) is transformed to obtain the expression for the magnetomotive force in the dq coordinate system, as shown below:

[0073]

[0074] in, These represent the magnetomotive force components on the d and q axes, respectively. Φ represents the reluctance components on the d and q axes, respectively. d Φ q Let ω represent the magnetic flux along the d and q axes, respectively, and let ω represent the angular velocity of the motor. This represents an antisymmetric matrix.

[0075] Step S132: Based on the magnetomotive force calculation formula of the permanent magnet synchronous motor, the relationship satisfied by the magnetomotive force is obtained.

[0076] Furthermore, based on the formula for calculating the magnetomotive force of a permanent magnet synchronous motor, the magnetomotive force also satisfies the following relationship:

[0077]

[0078] Where, N a Indicates the number of turns in each stator winding, i d i q These represent the current components on the d and q axes, respectively. This represents the magnetomotive force component generated by the permanent magnet.

[0079] Step S133: Obtain the magnetic flux on the d and q axes based on the expression of the magnetomotive force in the dq coordinate system and the relation it satisfies.

[0080] Solving equations (3) and (4) simultaneously yields the magnetic flux Φ on the d and q axes. d Φ q The specific expression is as follows:

[0081]

[0082] Step S134: Obtain the stator flux linkage equation based on the relationship between flux linkage and magnetic flux.

[0083] Based on the relationship between magnetic flux linkage and magnetic flux ψ=NΦ, the magnetic flux linkage ψ along the d and q axes can be obtained from equation (5). d ψ q The details are as follows:

[0084]

[0085] Simplify equation (6) and denote L. s =L d =L q Representing the stator inductance of a permanent magnet synchronous motor, we obtain the following expressions for the d-axis and q-axis flux linkages:

[0086]

[0087] Where, ψ f This refers to the magnetic flux generated by a permanent magnet. This represents a coefficient defined for ease of simplification.

[0088] Step S140: List the dynamic voltage equation of the permanent magnet synchronous motor and substitute the stator flux linkage equation into the motor voltage dynamic equation to obtain the accurate dynamic model of the permanent magnet synchronous motor considering core losses.

[0089] The dynamic voltage equations for the permanent magnet synchronous motor are listed below:

[0090]

[0091] Among them, u d u qR represents the voltage on the d and q axes. s This represents the stator resistance of a permanent magnet synchronous motor.

[0092] Substituting equation (7) into equation (8) yields an accurate dynamic model of the permanent magnet synchronous motor considering core losses, thus enabling accurate modeling of the motor. The specific expression is shown below:

[0093]

[0094] To simplify equation (9), we first define the coefficients L1, L2, and ψ. f1 and ψ f2 Where L1 and L2 represent the inductance parameters considering core losses, ψ f1 ψ f2 These represent the magnetic flux components of the permanent magnet, and their specific expressions are shown below:

[0095]

[0096] Then, by simplifying equation (9) and substituting equations (10) and (11) into the simplified result, we obtain the accurate dynamic model of the permanent magnet synchronous motor considering core losses, as shown in the following expression:

[0097]

[0098] Equation (12) is the accurate dynamic model of the permanent magnet synchronous motor considering core losses.

[0099] This embodiment establishes the magnetomotive force equation of the permanent magnet synchronous motor considering core losses, thereby obtaining an accurate stator flux linkage equation. Substituting this stator flux linkage equation into the motor voltage dynamic equation yields an accurate dynamic model of the permanent magnet synchronous motor considering core losses, making subsequent control more precise.

[0100] Step S200: Based on the accurate dynamic model of the permanent magnet synchronous motor considering core losses, derive a criterion that reflects the losses of the permanent magnet synchronous motor.

[0101] In this embodiment of the application, based on the accurate dynamic model of the permanent magnet synchronous motor considering core losses, a criterion reflecting the losses of the permanent magnet synchronous motor is derived, including:

[0102] Step S210: By using an accurate dynamic model of the permanent magnet synchronous motor that considers core losses, the loss equation and electromagnetic torque equation of the permanent magnet synchronous motor are derived.

[0103] Based on step S100, an accurate dynamic model of the permanent magnet synchronous motor considering core losses is obtained, and the losses P of the permanent magnet synchronous motor based on this model are listed. loss The electromagnetic torque equations are shown below:

[0104]

[0105] Among them, T em Represents electromagnetic torque, n p This indicates the number of pole pairs in a permanent magnet synchronous motor.

[0106] Step S220: Construct the Lagrangian function based on the loss equation and electromagnetic torque equation of the permanent magnet synchronous motor.

[0107] Step S230: Construct electromagnetic torque constraint conditions based on the torque accuracy requirements of permanent magnet synchronous motor control.

[0108] Furthermore, the electromagnetic torque constraint condition is as follows:

[0109]

[0110] Step S240: Combine the Lagrange function with the torque constraint to form a criterion that can reflect the losses of the permanent magnet synchronous motor.

[0111] Based on equations (13) and (14), a Lagrangian function is constructed as the loss criterion F, in which an electromagnetic torque constraint condition is introduced. To meet the torque accuracy requirements in motor control, its specific expression is as follows:

[0112]

[0113] Among them, T emref This indicates the reference value for the electromagnetic torque of a permanent magnet synchronous motor.

[0114] This embodiment uses a precise dynamic model of the permanent magnet synchronous motor considering core losses to obtain accurate loss equations and torque constraints. Based on this, a Lagrangian function is constructed, and an extreme value equation that satisfies torque control accuracy and loss minimization is established. This equation is the loss criterion that reflects the losses of the permanent magnet synchronous motor.

[0115] Step S300: Solve the loss criterion reflecting the loss of the permanent magnet synchronous motor using the Lagrange multiplier method to obtain the reference values ​​of the d-axis and q-axis currents.

[0116] Solving equation (15) using the Lagrange multiplier method, we establish a system of partial derivative equations, the specific expressions of which are shown below:

[0117]

[0118] The solution yields the d-axis current reference value i. dref and q-axis current reference value i qref The expression is as follows:

[0119]

[0120] The specific expressions for parameters A, B, C, D, and E are shown below:

[0121]

[0122] Step S400: Adjust the error between the actual current and the reference current according to the d-axis and q-axis current reference values, thereby outputting the reference voltage.

[0123] Specifically, the obtained reference current (17) is input into a proportional-integral (PI) controller to adjust the error between the actual current and the reference current to output a reference voltage.

[0124] Step S500: The output reference voltage is processed sequentially through coordinate transformation and space vector pulse width modulation algorithm to generate six switching signals for the inverter to control the inverter, thereby achieving closed-loop feedback and minimum loss control of the permanent magnet synchronous motor.

[0125] Specifically, the input control terminal of the permanent magnet synchronous motor is connected to the inverter. During the closed-loop feedback process, the reference voltage of the output permanent magnet synchronous motor is processed sequentially through coordinate transformation and space vector pulse width modulation (SVPWM) algorithm to generate six switching signals for the inverter to control the inverter. In turn, the inverter drives the permanent magnet synchronous motor to work normally, realizing the minimum loss control of the permanent magnet synchronous motor through closed-loop feedback.

[0126] In one specific embodiment, a motor with the following parameters was selected for simulation: 2 pole pairs, 5A rated current, 6Nm rated torque, 1250W rated power, 2000rad / min rated speed, and 0.001kg·m shaft moment of inertia. 2 . Reference Figure 2 As shown, using the control method of this invention (solid black line), the efficiency of the proposed control method generally increases within the torque range shown. Starting from a lower efficiency at a torque of 1 Nm, the efficiency gradually increases with increasing torque. The efficiency reaches approximately 88% at a torque of about 4 Nm, after which the efficiency increase slows down, approaching 90% at a torque of 6 Nm. In comparison, i d The efficiency of the control method with =0 is significantly lower than that of the control method proposed in this invention as the torque increases. Therefore, the method of this invention is obviously more advantageous in terms of energy utilization efficiency and control accuracy.

[0127] In one embodiment, a minimum loss control device for a permanent magnet synchronous motor based on the vector magnetic circuit law is proposed, the device comprising:

[0128] The precise dynamic model module is used to construct a precise dynamic model of a permanent magnet synchronous motor that takes into account core losses, based on the vector magnetic circuit law.

[0129] The loss criterion module is used to derive criteria that reflect the losses of permanent magnet synchronous motors based on an accurate dynamic model that takes into account the core losses of the permanent magnet synchronous motor.

[0130] The current reference value calculation module is used to solve the loss criteria reflecting the loss of the permanent magnet synchronous motor using the Lagrange multiplier method to obtain the d-axis and q-axis current reference values;

[0131] The reference voltage output module is used to adjust the error between the actual current and the reference current based on the d-axis and q-axis current reference values, thereby outputting a reference voltage.

[0132] The switching signal generation module is used to generate six switching signals for the inverter by processing the output reference voltage through coordinate transformation and space vector pulse width modulation algorithm, thereby controlling the inverter and realizing the minimum loss control of the closed-loop feedback of the permanent magnet synchronous motor.

[0133] It should be noted that the minimum loss control device for permanent magnet synchronous motors based on the vector magnetic circuit law provided in the above embodiments is only illustrated by the division of the above functional modules when executing the minimum loss control method for permanent magnet synchronous motors based on the vector magnetic circuit law. In practical applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above. In addition, the minimum loss control device for permanent magnet synchronous motors based on the vector magnetic circuit law provided in the above embodiments and the minimum loss control method embodiment for permanent magnet synchronous motors based on the vector magnetic circuit law belong to the same concept. The implementation process is detailed in the embodiment of the minimum loss control method for permanent magnet synchronous motors based on the vector magnetic circuit law, and will not be repeated here.

[0134] Reference Figure 3 As shown, in one embodiment, a permanent magnet synchronous motor control system is proposed, which includes the aforementioned permanent magnet synchronous motor minimum loss control device based on the vector magnetic circuit law.

[0135] The actual value of the three-phase current i measured from the permanent magnet motor a i b i c and actual rotor position θ e The actual rotor position θ e Used for coordinate transformation, this transforms the actual current to the α-β coordinate system to obtain the current feedback value i. d i q This facilitates motor control; then, the actual rotor position θ is determined. e Differentiation yields the rotational speed ω eThe rotational speed and the measured actual electrical charge value are input together into the loss criterion module of the permanent magnet synchronous motor minimum loss control device based on the vector magnetic circuit law to calculate the current reference value, thereby realizing feedback control of the entire system.

[0136] It should be noted that the description of the minimum loss control device for permanent magnet synchronous motor based on the vector magnetic circuit law refers to the above embodiment, and will not be repeated here.

[0137] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0138] In one embodiment, a computer-readable storage medium is provided, wherein the computer-readable instructions, when executed by one or more processors, cause the one or more processors to perform the steps of the above-described method for minimum loss control of a permanent magnet synchronous motor based on the vector magnetic circuit law. The steps include: constructing an accurate dynamic model of the permanent magnet synchronous motor considering core losses based on the vector magnetic circuit law; deriving a criterion reflecting the losses of the permanent magnet synchronous motor based on the accurate dynamic model considering core losses; solving the loss criterion reflecting the losses of the permanent magnet synchronous motor using the Lagrange multiplier method to obtain reference values ​​for the d-axis and q-axis currents; adjusting the error between the actual current and the reference current based on the reference values ​​for the d-axis and q-axis currents to output a reference voltage; and processing the output reference voltage sequentially through coordinate transformation and a space vector pulse width modulation algorithm to generate six switching signals for the inverter to control the inverter, thereby achieving closed-loop feedback minimum loss control of the permanent magnet synchronous motor.

[0139] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. This computer program can be stored in a computer-readable storage medium, and when executed, it can include the processes of the embodiments of the methods described above. The aforementioned storage medium can be a non-volatile storage medium such as a magnetic disk, optical disk, or read-only memory (ROM), or random access memory (RAM).

[0140] Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of the invention may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this specification.

[0141] Furthermore, those skilled in the art will understand that although some embodiments described herein include certain features found in other embodiments but not others, combinations of features from different embodiments are also within the scope of protection of this invention and form different embodiments. For example, in the embodiments described above, those skilled in the art can use them in combination based on known technical solutions and the technical problems to be solved by this application.

[0142] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-described technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for minimum loss control of a permanent magnet synchronous motor based on the vector magnetic circuit law, characterized in that: The method includes: An accurate dynamic model of a permanent magnet synchronous motor considering core losses is constructed based on the vector magnetic circuit law. Based on the accurate dynamic model of permanent magnet synchronous motor considering core losses, a criterion that can reflect the losses of permanent magnet synchronous motor is derived. The loss criterion for the permanent magnet synchronous motor is: ， in, This represents the reference value for the electromagnetic torque of a permanent magnet synchronous motor. For losses in permanent magnet synchronous motors. Represents the Lagrange multiplier. Indicates the number of magnetic pole pairs. These represent the current components on the d and q axes, respectively. , These represent the inductance parameters considering core losses. , These represent the magnetic flux components of the permanent magnet; The loss criteria reflecting the losses of permanent magnet synchronous motors are solved using the Lagrange multiplier method to obtain the reference values ​​of d-axis and q-axis currents; The error between the actual current and the reference current is adjusted according to the d-axis and q-axis current reference values, thereby outputting a reference voltage; The output reference voltage is processed sequentially through coordinate transformation and space vector pulse width modulation algorithm to generate six switching signals for the inverter, thereby controlling the inverter and achieving closed-loop feedback with minimum loss control of the permanent magnet synchronous motor.

2. The method for minimum loss control of permanent magnet synchronous motor based on vector magnetic circuit law according to claim 1, characterized in that: The accurate dynamic model of the permanent magnet synchronous motor considering core losses, based on the vector magnetic circuit law, includes: Construct the magnetomotive force equation of a permanent magnet synchronous motor considering core losses; Substituting the equivalent magnetic flux density parameters into the magnetomotive force equation of the permanent magnet synchronous motor considering core losses, based on the vector magnetic circuit law, we obtain the magnetomotive force equation of the permanent magnet synchronous motor considering core losses. The stator flux linkage equation is derived from the magnetomotive force equation of a permanent magnet synchronous motor considering core losses, based on the vector magnetic circuit law. The dynamic voltage equations of the permanent magnet synchronous motor are listed, and the stator flux linkage equations are substituted into the motor voltage dynamic equations to obtain an accurate dynamic model of the permanent magnet synchronous motor considering core losses.

3. The method for minimum loss control of a permanent magnet synchronous motor based on the vector magnetic circuit law according to claim 2, characterized in that: The stator flux linkage equation is derived from the magnetomotive force equation of a permanent magnet synchronous motor considering core losses based on the vector magnetic circuit law, including: The magnetomotive force equation based on the vector magnetic circuit law considering core loss is transformed by coordinate transformation to obtain the expression of magnetomotive force in the dq coordinate system; Based on the magnetomotive force calculation formula of permanent magnet synchronous motor, the relationship satisfied by the magnetomotive force is derived; The magnetic flux on the d and q axes can be derived from the expression of the magnetomotive force in the dq coordinate system and the relation it satisfies. The stator flux linkage equation is derived from the relationship between flux linkage and magnetic flux.

4. The method for minimum loss control of permanent magnet synchronous motor based on vector magnetic circuit law according to claim 1, characterized in that: The magnetomotive force equation of the permanent magnet synchronous motor based on the vector magnetic circuit law, considering core losses, is as follows: ， in, This represents the magnetomotive force of phases a, b, and c. Represents the magnetic reluctance along each axis in the a, b, c coordinate system. Represent the magnetic flux of phases a, b, and c, and define the iron loss coefficient. , Based on the vector magnetic circuit law, magnetic induction and virtual magnetic capacitance are expressed respectively. Indicates the angular velocity of the motor. Let p denote the third-order identity matrix, and let p denote the differential operator, which means differentiating over time.

5. The method for minimum loss control of a permanent magnet synchronous motor based on the vector magnetic circuit law according to claim 4, characterized in that: The accurate dynamic model of the permanent magnet synchronous motor considering core losses is as follows: , in, Represents the voltage on the d and q axes. This represents the stator resistance of a permanent magnet synchronous motor. Indicates the angular velocity of the motor. These represent the current components on the d and q axes, respectively. , These represent the inductance parameters considering core losses. , These represent the magnetic flux components of the permanent magnet.

6. The method for minimum loss control of a permanent magnet synchronous motor based on the vector magnetic circuit law according to claim 5, characterized in that: The precise dynamic model of the permanent magnet synchronous motor considering core losses yields criteria that reflect the losses of the permanent magnet synchronous motor, including: By using an accurate dynamic model of the permanent magnet synchronous motor considering core losses, the loss equation and electromagnetic torque equation of the permanent magnet synchronous motor are derived. Construct a Lagrangian function based on the loss equation and electromagnetic torque equation of a permanent magnet synchronous motor; Electromagnetic torque constraint conditions are constructed based on the torque accuracy requirements of permanent magnet synchronous motor control. The Lagrange function, combined with torque constraints, forms a loss criterion that can reflect the losses of a permanent magnet synchronous motor.

7. A minimum loss control device for a permanent magnet synchronous motor based on the vector magnetic circuit law, characterized in that: The device includes: The precise dynamic model module is used to construct a precise dynamic model of a permanent magnet synchronous motor that takes into account core losses, based on the vector magnetic circuit law. The loss criterion module is used to derive criteria that reflect the losses of permanent magnet synchronous motors based on an accurate dynamic model that takes into account the core losses of the permanent magnet synchronous motor. The loss criterion for the permanent magnet synchronous motor is: ， in, This represents the reference value for the electromagnetic torque of a permanent magnet synchronous motor. For losses in permanent magnet synchronous motors. Represents the Lagrange multiplier. Indicates the number of magnetic pole pairs. These represent the current components on the d and q axes, respectively. , These represent the inductance parameters considering core losses. , These represent the magnetic flux components of the permanent magnet; The current reference value calculation module is used to solve the loss criteria reflecting the loss of the permanent magnet synchronous motor using the Lagrange multiplier method to obtain the d-axis and q-axis current reference values; The reference voltage output module is used to adjust the error between the actual current and the reference current based on the d-axis and q-axis current reference values, thereby outputting a reference voltage. The switching signal generation module is used to generate six switching signals for the inverter by processing the output reference voltage through coordinate transformation and space vector pulse width modulation algorithm, thereby controlling the inverter and realizing the minimum loss control of the closed-loop feedback of the permanent magnet synchronous motor.

8. A permanent magnet synchronous motor control system, characterized in that, The system includes the minimum loss control device for permanent magnet synchronous motor based on the vector magnetic circuit law as described in claim 7.

9. A computer-readable storage medium, characterized in that, When the computer-readable storage medium is executed by one or more processors, the one or more processors perform the steps of the minimum loss control method for a permanent magnet synchronous motor based on the vector magnetic circuit law as described in any one of claims 1 to 8.

Images