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

Abstract

The invention discloses a method and a device for controlling the minimum loss of a permanent magnet synchronous motor based on a vector magnetic circuit law. The method comprises the following steps: establishing an accurate dynamic model of the permanent magnet synchronous motor considering core loss; obtaining a loss equation of the permanent magnet synchronous motor under the condition of considering iron core loss through the model, and forming a loss criterion F capable of reflecting the loss of the permanent magnet synchronous motor by combining a torque constraint condition; performing a Lagrange multiplier method on the loss criterion F to obtain a d-axis current reference value and a q-axis current reference value; inputting the d-axis reference current and the q-axis reference current into a proportional integral (PI) controller, and adjusting an error between the actual current and the reference current to output a reference voltage; after the output reference voltage is processed through coordinate transformation and a space vector pulse width modulation algorithm in sequence, six paths of switching signals of an inverter are generated to control the inverter, then the inverter drives the permanent magnet synchronous motor to work normally, and minimum loss control of closed-loop feedback of the permanent magnet synchronous motor is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of motor loss control, and in particular to a method and device for minimum loss control of a permanent magnet synchronous motor based on a vector magnetic circuit law. Background Art

[0002] Permanent magnet synchronous motors play an important role in the industrial field due to their significant advantages such as high efficiency, high power density and good speed regulation performance. They are widely used in many fields such as industrial automation, new energy vehicles and rail transportation. However, core loss often occurs during the operation of permanent magnet synchronous motors. During the operation of the motor, part of the input electrical energy will be converted into heat energy in the form of core loss and dissipated, and cannot be effectively converted into mechanical energy output, which makes the output power of the motor relatively reduced and affects its energy utilization efficiency. Core loss includes hysteresis loss and eddy current loss, both of which are related to the motor speed, voltage effective value and magnetic induction intensity, and their change rules are more complicated under different motor operating conditions (such as high-speed operation, different load conditions, etc.). Usually, in order to simplify the mathematical model of permanent magnet synchronous motors, the existence of core loss is ignored.

[0003] Since the mathematical model that ignores the core loss cannot fully reflect the actual operation of the motor, the control strategy derived on this basis will inevitably reflect its limitations in practical applications. Therefore, motor control technology is developing in a more accurate, efficient and reliable direction, paying more and more attention to various practical factors in motor operation (such as core loss, inverter loss, harmonic effects, etc.), and constantly optimizing the control strategy to improve the overall performance of the motor.

[0004] The traditional control method that ignores the core loss uses a mathematical model that fails to reflect the core loss, which is an actual influencing factor, and cannot fully reflect the actual operation of the motor. The control strategy derived from such a model has limitations, the control accuracy is low, and it is difficult to meet the demand for high-performance control of the motor. The permanent magnet synchronous motor control method based on fuzzy control does not directly model and calculate the core loss accurately. Usually, it only monitors the overall operating status of the motor and adjusts it according to fuzzy rules to indirectly deal with the operating conditions that may be affected by the core loss. However, this method lacks quantitative analysis and precise control of the core loss, so the stability and consistency of its control effect are relatively limited.

[0005] Therefore, it is urgent to propose a permanent magnet synchronous motor minimum loss control method to achieve high-quality control of the permanent magnet synchronous motor while considering the core loss. Summary of the invention

[0006] The purpose of the present invention is to provide a method and device for controlling the minimum loss of a permanent magnet synchronous motor based on the vector magnetic circuit law. The method is used to solve the problem that the existence of core loss is often ignored in the modeling and control of permanent magnet synchronous motors, thereby affecting the accuracy of motor control. The present invention proposes a method for controlling the minimum loss of a permanent magnet synchronous motor. The method performs minimum loss control on the permanent magnet synchronous motor under accurate modeling considering the core loss, thereby achieving high-quality control of the permanent magnet synchronous motor.

[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 controlling a permanent magnet synchronous motor with minimum loss based on a vector magnetic circuit law, the method comprising:

[0009] Based on the vector magnetic circuit law, an accurate dynamic model of permanent magnet synchronous motor considering core loss is constructed;

[0010] Based on the accurate dynamic model of permanent magnet synchronous motor considering core loss, a criterion that can reflect the loss of permanent magnet synchronous motor is obtained;

[0011] The loss criterion reflecting the permanent magnet synchronous motor loss is solved by Lagrange multiplier method to obtain the d and q axis current reference values;

[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 in turn through coordinate transformation and space vector pulse width modulation algorithm to generate six switching signals of the inverter to control the inverter, thereby realizing minimum loss control of closed-loop feedback of the permanent magnet synchronous motor.

[0014] In one embodiment, the method of constructing an accurate dynamic model of a permanent magnet synchronous motor taking into account core loss based on the vector magnetic circuit law includes:

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

[0016] The equivalent magnetic inductance and magnetic capacitance parameters are defined according to the vector magnetic circuit law and substituted into the magnetomotive force equation of the permanent magnet synchronous motor under the consideration of core loss, and the magnetomotive force equation of the permanent magnet synchronous motor under the consideration of core loss based on the vector magnetic circuit law is obtained;

[0017] The stator flux equation is derived from the magnetomotive force equation of the permanent magnet synchronous motor based on the vector magnetic circuit law with core loss taken into account;

[0018] The dynamic voltage equation of the permanent magnet synchronous motor is listed, and the stator flux equation is substituted into the motor voltage dynamic equation to obtain an accurate dynamic model of the permanent magnet synchronous motor considering the core loss.

[0019] In one embodiment, the stator flux equation is obtained according to the magnetomotive force equation of the permanent magnet synchronous motor based on the vector magnetic circuit law taking into account the core loss, including:

[0020] The magnetomotive force equation based on the vector magnetic circuit law with consideration of core loss is transformed into the expression of magnetomotive force in the dq coordinate system.

[0021] According to the calculation formula of the magnetomotive force of the permanent magnet synchronous motor, the relationship satisfied by the magnetomotive force is obtained;

[0022] The magnetic flux on the d and q axes is obtained based on the expression of the magnetomotive force in the dq coordinate system and the relationship it satisfies;

[0023] The stator flux equation is obtained based on the relationship between flux and magnetic flux.

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

[0025]

[0026] in, represents the magnetomotive force of phases a, b, and c, Represents the magnetic reluctance of each axis in the a, b, and c coordinate systems, Φ abc Represents the magnetic flux of phases a, b, and c, and defines the iron loss coefficient According to the vector magnetic circuit law, the magnetic induction and virtual magnetic capacitance are expressed respectively, I 3×3 Represents the third-order unit matrix, p represents the differential operator, which means to differentiate with respect to time.

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

[0028]

[0029] Among them, ψ f represents the permanent magnet flux, Represents a coefficient defined for the convenience of simplification.

[0030] In one implementation, the precise dynamic model of the permanent magnet synchronous motor taking into account the core loss is:

[0031]

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

[0033] In one embodiment, the method of obtaining a criterion capable of reflecting the loss of the permanent magnet synchronous motor based on an accurate dynamic model of the permanent magnet synchronous motor taking into account the core loss includes:

[0034] Through the accurate dynamic model of permanent magnet synchronous motor considering the core loss, the permanent magnet synchronous motor loss equation and electromagnetic torque equation are obtained;

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

[0036] Construct electromagnetic torque constraint conditions according to the torque accuracy requirements of permanent magnet synchronous motor control;

[0037] The Lagrangian function is combined with the torque constraint condition to form a criterion that can reflect the loss of permanent magnet synchronous motor.

[0038] In one implementation, the loss criterion of the permanent magnet synchronous motor loss is:

[0039]

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

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

[0042] Accurate dynamic model module, used to build an accurate dynamic model of permanent magnet synchronous motor considering core loss based on vector magnetic circuit law;

[0043] The loss criterion module is used to obtain a criterion that can reflect the loss of the permanent magnet synchronous motor based on an accurate dynamic model that considers the core loss of the permanent magnet synchronous motor;

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

[0045] A reference voltage output module is used to adjust the error between the actual current and the reference current according to the d-axis and q-axis current reference values, thereby outputting a reference voltage;

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

[0047] In a third aspect, the present invention provides a permanent magnet synchronous motor control system, the system comprising the above-mentioned permanent magnet synchronous motor minimum loss control device based on the vector magnetic circuit law.

[0048] In a fourth aspect, the present invention provides a computer-readable storage medium having computer program instructions stored thereon, which, when executed by a processor, implement the above-mentioned method for minimum loss control of a permanent magnet synchronous motor based on the vector magnetic circuit law.

[0049] The technical solution provided by the embodiments of the present application may have the following beneficial effects:

[0050] The present invention accurately models the motor based on the vector magnetic circuit law, making the description of the motor more in line with the actual operating conditions, providing a solid foundation for subsequent control strategies, and achieving more precise control. The loss criterion is solved by the Lagrange multiplier method to obtain the d and q axis current reference values, and then the actual current and the reference current error are adjusted to output the reference voltage, and finally the inverter is controlled to achieve the minimum loss control of the motor closed-loop feedback. In principle, this process comprehensively considers and accurately calculates the core loss, can adjust the motor operating parameters in a targeted manner, effectively reduce various losses including core loss, and improve the overall performance of the motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] The accompanying drawings are part of the present invention and are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention, but do not constitute an improper limitation of the present invention. Obviously, the accompanying drawings described below are only some embodiments. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without creative work.

[0052] Figure 1 A flow chart of a method for controlling a permanent magnet synchronous motor with minimum loss based on a vector magnetic circuit law provided by an embodiment of the present invention;

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

[0054] Figure 3The two control methods of the permanent magnet synchronous motor under different torques when the speed is 2000r / min (the method of the present invention and the method of the present invention) are shown in FIG. d =0 method) efficiency comparison chart.

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

[0056] In order to deepen the recognition and understanding of the present invention, the technical solution of the present invention is further introduced below in conjunction with the accompanying drawings and specific implementation methods. The following embodiments are explanations of the present invention and the present invention is not limited to the following embodiments.

[0057] It should be clear that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0058] Reference Figure 1 As shown, an embodiment of the present invention provides a method for controlling a permanent magnet synchronous motor with minimum loss based on a vector magnetic circuit law, the method comprising the following steps:

[0059] Step S100: constructing an accurate dynamic model of the permanent magnet synchronous motor taking into account the core loss based on the vector magnetic circuit law.

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

[0061] Step S110: constructing a magnetomotive force equation of the permanent magnet synchronous motor taking into account core loss.

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

[0063]

[0064] in, represents the magnetomotive force of phases a, b, and c, Represents the magnetic reluctance of each axis in the a, b, and c coordinate systems, Φ abc represents the magnetic flux of phases a, b, and c, According to the vector magnetic circuit law, magnetic induction and virtual magnetic capacitance are respectively expressed. Magnetic resistance reflects the degree of resistance of magnetic circuit materials and geometric shapes to magnetic flux; magnetic induction can quantitatively reflect the resistance of the induced current generated by the magnetic flux of the equivalent winding closed loop in the magnetic circuit to the magnetic field in the magnetic circuit; virtual magnetic capacitance can represent the hysteresis effect of magnetic materials under alternating magnetic flux. 3×3Represents the third-order unit matrix, p represents the differential operator, which means to differentiate with respect to time.

[0065] Step S120: define equivalent magnetic inductance and magnetic capacitance parameters according to the vector magnetic circuit law and substitute them into the magnetomotive force equation of the permanent magnet synchronous motor considering the core loss, so as to obtain the magnetomotive force equation of the permanent magnet synchronous motor considering the core loss based on the vector magnetic circuit law.

[0066] The input of permanent magnet synchronous motor is three-phase sinusoidal current, so three-phase sinusoidal magnetic flux will be generated inside the motor. The numerical relationship between the iron loss coefficient and Substituting it into equation (1) simplifies the magnetomotive force equation as follows:

[0067]

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

[0069] Step S130: deriving a stator flux equation according to a magnetomotive force equation of a permanent magnet synchronous motor based on a vector magnetic circuit law and taking into account core loss.

[0070] In the embodiment of the present application, the stator flux equation is obtained according to the magnetomotive force equation of the permanent magnet synchronous motor based on the vector magnetic circuit law considering the core loss, including:

[0071] Step S131: performing coordinate transformation on the magnetomotive force equation based on the vector magnetic circuit law taking into account the core loss to obtain an expression of the magnetomotive force in the dq coordinate system.

[0072] The expression of magnetomotive force in the dq coordinate system is obtained by transforming equation (2), which is as follows:

[0073]

[0074] in, denote the magnetomotive force components on the d and q axes respectively, Represent the magnetic resistance components on the d and q axes respectively, Φ d , Φ q Respectively represent the magnetic flux on the d and q axes, ω represents the motor angular velocity, represents an antisymmetric matrix.

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

[0076] Furthermore, according to the calculation formula of the magnetomotive force of the permanent magnet synchronous motor, the magnetomotive force also satisfies the following relationship:

[0077]

[0078] Among them, N a Indicates the number of turns of each stator winding, i d 、i q Represent the current components on the d and q axes respectively, Represents the magnetomotive force component generated by the permanent magnet.

[0079] Step S133: derive the magnetic flux on the d and q axes according to the expression of the magnetomotive force in the dq coordinate system and the relationship it satisfies.

[0080] Solving equation (3) and equation (4) together, we can get the magnetic flux Φ on the d and q axes: d , Φ q , the expression is as follows:

[0081]

[0082] Step S134: Obtain the stator flux equation according to the relationship between flux and magnetic flux.

[0083] According to the relationship between magnetic flux and magnetic flux ψ=NΦ, the d-axis and q-axis magnetic flux ψ can be obtained from equation (5): d , q , as shown below:

[0084]

[0085] Simplify equation (6) and denote L s =L d =L q Represents the stator inductance of the permanent magnet synchronous motor, and the following d-axis and q-axis flux expressions are obtained:

[0086]

[0087] Among them, ψ f represents the flux generated by the permanent magnet, Represents a coefficient defined for convenience in simplification.

[0088] Step S140: List the dynamic voltage equation of the permanent magnet synchronous motor, and substitute the stator flux equation into the motor voltage dynamic equation to obtain an accurate dynamic model of the permanent magnet synchronous motor taking into account the core loss.

[0089] The dynamic voltage equation of the permanent magnet synchronous motor is listed as follows:

[0090]

[0091] Among them, u d 、u qRepresents the voltage on the d and q axes, R s Represents the stator resistance of the permanent magnet synchronous motor.

[0092] Substituting equation (7) into equation (8) yields an accurate dynamic model of the permanent magnet synchronous motor taking into account the core loss, thereby accurately modeling the motor. The specific expression is as follows:

[0093]

[0094] To simplify equation (9), we first define the coefficients L1, L2, ψ f1 and ψ f2 Among them, L1 and L2 represent the inductance parameters considering the core loss, ψ f1 , f2 They represent the permanent magnet flux components respectively, and their expressions are as follows:

[0095]

[0096] Then, equation (9) is simplified and equations (10) and (11) are substituted into the simplified results to obtain the accurate dynamic model of the permanent magnet synchronous motor considering the core loss. The specific expression is as follows:

[0097]

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

[0099] This embodiment establishes the magnetomotive force equation of the permanent magnet synchronous motor taking into account the core loss, and obtains an accurate stator flux equation based on it. This stator flux equation is substituted into the motor voltage dynamic equation to obtain an accurate dynamic model of the permanent magnet synchronous motor taking into account the core loss, so that subsequent control is more accurate.

[0100] Step S200: deriving a criterion capable of reflecting the loss of the permanent magnet synchronous motor according to an accurate dynamic model of the permanent magnet synchronous motor taking into account the core loss.

[0101] In the embodiment of the present application, according to the accurate dynamic model of the permanent magnet synchronous motor considering the core loss, a criterion capable of reflecting the loss of the permanent magnet synchronous motor is obtained, including:

[0102] Step S210: deriving a permanent magnet synchronous motor loss equation and an electromagnetic torque equation through an accurate dynamic model of the permanent magnet synchronous motor taking into account core loss.

[0103] According to step S100, an accurate dynamic model of the permanent magnet synchronous motor considering the core loss is obtained, and the permanent magnet synchronous motor loss P based on this model is listed. loss And the electromagnetic torque equation, whose expressions are as follows:

[0104]

[0105] Among them, T em represents the electromagnetic torque, n p Indicates the number of magnetic pole pairs of a permanent magnet synchronous motor.

[0106] Step S220: constructing a Lagrangian function according to the permanent magnet synchronous motor loss equation and the electromagnetic torque equation.

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

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

[0109]

[0110] Step S240: combining the Lagrangian function with the torque constraint condition to form a criterion that can reflect the permanent magnet synchronous motor loss.

[0111] According to equations (13) and (14), the Lagrangian function is constructed as the loss criterion F, in which the electromagnetic torque constraint condition is introduced In order to meet the requirements of torque accuracy in motor control, the specific expression is as follows:

[0112]

[0113] Among them, T emref Indicates the electromagnetic torque reference value of the permanent magnet synchronous motor.

[0114] In this embodiment, an accurate dynamic model of the permanent magnet synchronous motor taking into account the core loss is used to obtain an accurate loss equation and torque constraint conditions, and a Lagrangian function is constructed based on this to establish an extreme value equation that satisfies the torque control accuracy and loss minimization. This equation is the loss criterion that can reflect the permanent magnet synchronous motor loss.

[0115] Step S300: performing a Lagrange multiplier method on a loss criterion reflecting the permanent magnet synchronous motor loss to obtain d-axis and q-axis current reference values.

[0116] The Lagrange multiplier method is used to solve equation (15) and a partial derivative equation system is established. The specific expression is as follows:

[0117]

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

[0119]

[0120] The expressions of the parameters A, B, C, D and E are as follows:

[0121]

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

[0123] Specifically, the obtained reference current formula (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 by coordinate transformation and space vector pulse width modulation algorithm in sequence to generate six switching signals of the inverter to control the inverter, thereby realizing minimum loss control of closed-loop feedback of the permanent magnet synchronous motor.

[0125] Specifically, the input control end 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 in turn through coordinate transformation and space vector pulse width modulation (SVPWM) algorithm to generate six switching signals of the inverter to control the inverter, and then the permanent magnet synchronous motor is driven by the inverter to work normally, thereby realizing the minimum loss control of the closed-loop feedback of the permanent magnet synchronous motor.

[0126] In a specific embodiment, a motor with the following parameters is selected for simulation: the number of pole pairs is 2, the rated current effective value is 5A, the rated torque is 6Nm, the rated power is 1250W, the rated speed is 2000rad / min, and the shaft rotation inertia is 0.001kg·m 2 . Reference Figure 2 As shown in the figure, using the control method of the present invention (black solid line), the efficiency of the proposed control method shows an overall upward trend within the torque range shown. Starting from a relatively low efficiency at a torque of 1 Nm, the efficiency gradually increases as the torque increases. When the torque reaches about 4 Nm, the efficiency reaches about 88%, and then the efficiency growth slows down. At a torque of 6 Nm, the efficiency is close to 90%. In comparison, d = 0, the efficiency is obviously lower than the control method proposed in the present invention as the torque increases. Therefore, the method of the present invention is obviously more advantageous in terms of energy utilization efficiency and control accuracy.

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

[0128] Accurate dynamic model module, used to build an accurate dynamic model of permanent magnet synchronous motor considering core loss based on vector magnetic circuit law;

[0129] The loss criterion module is used to obtain a criterion that can reflect the loss of the permanent magnet synchronous motor based on an accurate dynamic model that considers the core loss of the permanent magnet synchronous motor;

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

[0131] A reference voltage output module is used to adjust the error between the actual current and the reference current according to the d-axis and q-axis current reference values, thereby outputting a reference voltage;

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

[0133] It should be noted that the permanent magnet synchronous motor minimum loss control device based on the vector magnetic circuit law provided in the above embodiment only uses the division of the above functional modules as an example when executing the permanent magnet synchronous motor minimum loss control method based on the vector magnetic circuit law. In actual applications, the above functional distribution can be completed by different functional modules as needed, that is, the internal structure of the device is divided into different functional modules to complete all or part of the functions described above. In addition, the permanent magnet synchronous motor minimum loss control device based on the vector magnetic circuit law provided in the above embodiment and the permanent magnet synchronous motor minimum loss control method embodiment based on the vector magnetic circuit law belong to the same concept. The implementation process thereof is detailed in the permanent magnet synchronous motor minimum loss control method embodiment based on the vector magnetic circuit law, which 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 above-mentioned permanent magnet synchronous motor minimum loss control device based on the vector magnetic circuit law.

[0135] The actual value of the three-phase current measured from the permanent magnet motor is i a 、i b 、i c and the actual rotor position θ e , where the actual rotor position θ e Used for coordinate transformation, the actual current is transformed into the α-β coordinate system through coordinate transformation to obtain the current feedback value i d 、i q , which is convenient for controlling the motor; then the actual rotor position θ e Take the derivative to get the speed ω eThe speed and the measured actual value of the electric quantity are input together into the loss criterion module in the permanent magnet synchronous motor minimum loss control device based on the vector magnetic circuit law to calculate the current reference value, thereby realizing the feedback control of the whole system.

[0136] It should be noted that the description of the permanent magnet synchronous motor minimum loss control device 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 may be combined arbitrarily. To make the description concise, 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 proposed, and when the computer-readable instructions are executed by one or more processors, the one or more processors execute the steps of the above-mentioned permanent magnet synchronous motor minimum loss control method based on the vector magnetic circuit law, and the steps include: constructing an accurate dynamic model of the permanent magnet synchronous motor considering the core loss based on the vector magnetic circuit law; deriving a criterion that can reflect the loss of the permanent magnet synchronous motor according to the accurate dynamic model of the permanent magnet synchronous motor considering the core loss; solving the loss criterion reflecting the loss of the permanent magnet synchronous motor by the Lagrange multiplier method to obtain d-axis and q-axis current reference values; adjusting the error between the actual current and the reference current according to the d-axis and q-axis current reference values, thereby outputting a reference voltage; and processing the output reference voltage in turn through coordinate transformation and space vector pulse width modulation algorithm to generate six switching signals of the inverter to control the inverter, thereby realizing the closed-loop feedback minimum loss control of the permanent magnet synchronous motor.

[0139] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiments can be implemented by instructing the relevant hardware through a computer program, and the computer program can be stored in a computer-readable storage medium. When the program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, the aforementioned storage medium can be a non-volatile storage medium such as a disk, an optical disk, a read-only memory (ROM), or a random access memory (RAM).

[0140] In the description provided herein, a large number of specific details are described. However, it is understood that embodiments of the present invention can be practiced without these specific details. In some instances, well-known methods, structures and techniques are not shown in detail so as not to obscure the understanding of this description.

[0141] In addition, those skilled in the art will understand that, although some embodiments described herein include certain features included in other embodiments but not other features, the combination of features of different embodiments also means being within the scope of protection of the present invention and forming different embodiments. For example, in the above embodiments, those skilled in the art can use them in combination according to the known technical solutions and the technical problems to be solved by this application.

[0142] The above is only a preferred embodiment of the present invention, and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with this patent can make some changes or modify the technical contents suggested above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the solution of the present invention.

Claims

1. A method for controlling the minimum loss of a permanent magnet synchronous motor based on the vector magnetic circuit law, characterized in that: The method comprises: Based on the vector magnetic circuit law, an accurate dynamic model of permanent magnet synchronous motor considering core loss is constructed; Based on the accurate dynamic model of permanent magnet synchronous motor considering core loss, a criterion that can reflect the loss of permanent magnet synchronous motor is obtained; The loss criterion reflecting the permanent magnet synchronous motor loss is solved by Lagrange multiplier method to obtain the d and q axis current reference values; 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 in turn through coordinate transformation and space vector pulse width modulation algorithm to generate six switching signals of the inverter to control the inverter, thereby realizing minimum loss control of closed-loop feedback of the permanent magnet synchronous motor.

2. The method for controlling the minimum loss of a permanent magnet synchronous motor based on the vector magnetic circuit law according to claim 1 is characterized in that: The accurate dynamic model of the permanent magnet synchronous motor considering the core loss is constructed based on the vector magnetic circuit law, including: Construct the magnetomotive force equation of permanent magnet synchronous motor considering core loss; The equivalent magnetic inductance and magnetic capacitance parameters are defined according to the vector magnetic circuit law and substituted into the magnetomotive force equation of the permanent magnet synchronous motor under the consideration of core loss, and the magnetomotive force equation of the permanent magnet synchronous motor under the consideration of core loss based on the vector magnetic circuit law is obtained; The stator flux equation is derived from the magnetomotive force equation of the permanent magnet synchronous motor based on the vector magnetic circuit law with core loss taken into account; The dynamic voltage equation of the permanent magnet synchronous motor is listed, and the stator flux equation is substituted into the motor voltage dynamic equation to obtain an accurate dynamic model of the permanent magnet synchronous motor considering the core loss.

3. The method for controlling the minimum loss of a permanent magnet synchronous motor based on the vector magnetic circuit law according to claim 2 is characterized in that: The stator flux equation is obtained according to the magnetomotive force equation of the permanent magnet synchronous motor based on the vector magnetic circuit law considering the core loss, including: The magnetomotive force equation based on the vector magnetic circuit law with consideration of core loss is transformed into the expression of magnetomotive force in the dq coordinate system. According to the calculation formula of the magnetomotive force of the permanent magnet synchronous motor, the relationship satisfied by the magnetomotive force is obtained; The magnetic flux on the d and q axes is obtained based on the expression of the magnetomotive force in the dq coordinate system and the relationship it satisfies; The stator flux equation is obtained based on the relationship between flux and magnetic flux.

4. The method for controlling the minimum loss of a permanent magnet synchronous motor based on the vector magnetic circuit law according to claim 1 is characterized in that: The magnetomotive force equation of the permanent magnet synchronous motor based on the vector magnetic circuit law considering the core loss is: in, represents the magnetomotive force of phases a, b, and c, Represents the magnetic reluctance of each axis in the a, b, and c coordinate systems, Φ abc Represents the magnetic flux of phases a, b, and c, and defines the iron loss coefficient According to the vector magnetic circuit law, the magnetic induction and virtual magnetic capacitance are expressed respectively, I 3×3 Represents the third-order unit matrix, p represents the differential operator, which means to differentiate with respect to time.

5. The method for controlling the minimum loss of a permanent magnet synchronous motor based on the vector magnetic circuit law according to claim 4 is characterized in that: The precise dynamic model of the permanent magnet synchronous motor considering the core loss is: Among them, u d 、u q Represents the voltage on the d and q axes, R s represents the stator resistance of the permanent magnet synchronous motor, ω represents the motor angular velocity, i d 、i q They represent the current components on the d and q axes respectively, L1 and L2 represent the inductance parameters considering the core loss, ψ f1 , f2 They represent the permanent magnet flux components respectively.

6. The method for controlling the minimum loss of a permanent magnet synchronous motor based on the vector magnetic circuit law according to claim 5 is characterized in that: The accurate dynamic model of the permanent magnet synchronous motor considering the core loss is used to obtain the criterion that can reflect the loss of the permanent magnet synchronous motor, including: Through the accurate dynamic model of permanent magnet synchronous motor considering the core loss, the permanent magnet synchronous motor loss equation and electromagnetic torque equation are obtained; Construct the Lagrangian function based on the permanent magnet synchronous motor loss equation and electromagnetic torque equation; Construct electromagnetic torque constraint conditions according to the torque accuracy requirements of permanent magnet synchronous motor control; The Lagrangian function is combined with the torque constraint condition to form a loss criterion that can reflect the loss of the permanent magnet synchronous motor.

7. The method for controlling the minimum loss of a permanent magnet synchronous motor based on the vector magnetic circuit law according to claim 6 is characterized in that: The loss criterion of the permanent magnet synchronous motor loss is: Among them, T emref Represents the electromagnetic torque reference value of the permanent magnet synchronous motor, P loss is the permanent magnet synchronous motor loss, δ represents the Lagrange multiplier, n p represents the number of magnetic pole pairs, i d 、i q They represent the current components on the d and q axes respectively, L1 and L2 represent the inductance parameters considering the core loss, ψ f1 , f2 They represent the permanent magnet flux components respectively.

8. A permanent magnet synchronous motor minimum loss control device based on the vector magnetic circuit law, characterized in that: The device comprises: Accurate dynamic model module, used to build an accurate dynamic model of permanent magnet synchronous motor considering core loss based on vector magnetic circuit law; The loss criterion module is used to obtain a criterion that can reflect the loss of the permanent magnet synchronous motor based on an accurate dynamic model that considers the core loss of the permanent magnet synchronous motor; A current reference value calculation module is used to solve the loss criterion reflecting the permanent magnet synchronous motor loss by Lagrange multiplier method to obtain d-axis and q-axis current reference values; A reference voltage output module is used to adjust the error between the actual current and the reference current according to the d-axis and q-axis current reference values, thereby outputting a reference voltage; The switch signal generation module is used to process the output reference voltage through coordinate transformation and space vector pulse width modulation algorithm in sequence to generate six switch signals of the inverter to control the inverter, thereby realizing minimum loss control of the closed-loop feedback of the permanent magnet synchronous motor.

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

10. A computer-readable storage medium, characterized in that: When the computer-readable instructions are executed by one or more processors, the one or more processors execute the steps of the permanent magnet synchronous motor minimum loss control method based on the vector magnetic circuit law as described in any one of claims 1 to 7.

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