Maxwell-based permanent magnet synchronous motor magnetic field simulation method

Abstract

The invention relates to a Maxwell-based permanent magnet synchronous motor magnetic field simulation method, and belongs to the technical field of motor simulation methods. According to the Maxwell-based permanent magnet synchronous motor magnetic field simulation method, a finite element analysis method is adopted to carry out analogue simulation on a permanent magnet synchronous motor magnetic field, a Maxwell mathematical model is established, and Maxwell is utilized to carry out numerical simulation analysis, so that no-load operation characteristics and rated load operation characteristics of a permanent magnet synchronous motor are obtained. A simulation result verifies the starting characteristic and the dynamic performance of a permanent magnet synchronous motor magnetic field, and a foundation is laid for later optimization of the permanent magnet synchronous motor.

Description

Technical Field

[0001] The present invention relates to the technical field of motor simulation methods, in particular to the technical field of permanent magnet synchronous motor magnetic field simulation methods, specifically to a permanent magnet synchronous motor magnetic field simulation method based on Maxwell. Background Art

[0002] Permanent magnet synchronous motors (PMSMs) are increasingly used in the mechanical manufacturing industry. Compared to traditional electric motors, PMSMs convert electrical energy directly into mechanical energy, offering advantages such as low heat generation, high efficiency, simple structure, and high reliability. However, PMSMs are susceptible to external disturbances, resulting in complex dynamic performance.

[0003] How to verify the starting characteristics and dynamic performance of the permanent magnet synchronous motor's magnetic field during permanent magnet synchronous motor design, especially to calculate parameters such as the motor's stator winding inductance, motor back electromotive force, and reluctance torque, to provide a data basis for the subsequent optimization of the permanent magnet synchronous motor, is the most pressing technical problem to be solved in permanent magnet synchronous motor design. Summary of the Invention

[0004] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a permanent magnet synchronous motor magnetic field simulation method based on Maxwell.

[0005] In order to achieve the above-mentioned purpose, the Maxwell-based permanent magnet synchronous motor magnetic field simulation method of the present invention is characterized by comprising the following steps:

[0006] (1) Determine the parameter characteristics of the permanent magnet synchronous motor and build a mathematical model of the permanent magnet synchronous motor;

[0007] (2) Use the RMxprt module to design the magnetic circuit of the motor, call the corresponding module to select the motor model, input the physical parameters of the motor and set the rated data of the motor to obtain the RMxprt model;

[0008] (3) Export the RMxprt model directly to the Maxwell 2D module, set various material properties, add vector boundary conditions and set the excitation source;

[0009] (4) In Maxwell 2D, the stator winding of the permanent magnet synchronous motor is set to open circuit, and the excitation of the power supply is set to 0. The internal magnetic field is established by the permanent magnet to simulate the dynamic characteristics of the permanent magnet synchronous motor under no-load operation.

[0010] In the Maxwell-based permanent magnet synchronous motor magnetic field simulation method, the step (4) further includes:

[0011] Perform electromotive force simulation of permanent magnet synchronous motor under no-load operation.

[0012] The Maxwell-based permanent magnet synchronous motor magnetic field simulation method also includes:

[0013] (5) The Rmxprt model is imported into a new Maxwell 2D module again. The power source is selected as a voltage source and the initial current is 0A to simulate the load-carrying operation characteristics of the permanent magnet synchronous motor.

[0014] In the Maxwell-based permanent magnet synchronous motor magnetic field simulation method, the step (5) further includes:

[0015] Perform air gap magnetic field simulation of permanent magnet synchronous motor.

[0016] In the Maxwell-based permanent magnet synchronous motor magnetic field simulation method, the step (5) further includes:

[0017] The matrix change law simulation is performed when the permanent magnet synchronous motor is operating at full load.

[0018] The invention's Maxwell-based permanent magnet synchronous motor magnetic field simulation method uses finite element analysis to simulate the permanent magnet synchronous motor's magnetic field. A Maxwell mathematical model is constructed, and numerical simulation analysis is performed using Maxwell to derive the no-load and rated load operating characteristics of the permanent magnet synchronous motor. The simulation results verify the starting characteristics and dynamic performance of the permanent magnet synchronous motor's magnetic field, laying the foundation for future optimization of the permanent magnet synchronous motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Flowchart of the steps of the Maxwell-based permanent magnet synchronous motor magnetic field simulation method of the present invention;

[0020] Figure 2a A schematic diagram of the magnetic field line distribution of a permanent magnet synchronous motor simulating no-load operation using the method of the present invention;

[0021] Figure 2b To simulate the magnetic flux density distribution cloud diagram of a permanent magnet synchronous motor running at no load by using the method of the present invention;

[0022] Figure 3 This is a schematic diagram of the results of simulating the no-load back electromotive force of a permanent magnet synchronous motor using the method of the present invention;

[0023] Figure 4a A schematic diagram of the magnetic field line distribution of a permanent magnet synchronous motor simulating rated load operation using the method of the present invention;

[0024] Figure 4b The method of the present invention is used to simulate the magnetic line distribution cloud diagram of the permanent magnet synchronous motor running at rated load;

[0025] Figure 5 This is a schematic diagram of the simulation results of the air gap magnetic field of a permanent magnet synchronous motor under load using the method of the present invention;

[0026] Figure 6 The diagram is a schematic diagram of the torque variation law of a permanent magnet synchronous motor in full load state simulated by the method of the present invention. DETAILED DESCRIPTION

[0027] In order to more clearly understand the technical content of the present invention, the following embodiments are given to explain it in detail.

[0028] See also Figure 1 FIG. 1 is a flowchart of the steps of the Maxwell-based permanent magnet synchronous motor magnetic field simulation method of the present invention.

[0029] In one embodiment, the Maxwell-based permanent magnet synchronous motor magnetic field simulation method includes the following steps:

[0030] (1) Determine the parameter characteristics of the permanent magnet synchronous motor and build a mathematical model of the permanent magnet synchronous motor;

[0031] (2) Use the RMxprt module to design the magnetic circuit of the motor, call the corresponding module to select the motor model, input the physical parameters of the motor and set the rated data of the motor to obtain the RMxprt model;

[0032] (3) Export the RMxprt model directly to the Maxwell 2D module, set various material properties, add vector boundary conditions and set the excitation source;

[0033] (4) In Maxwell 2D, the stator winding of the permanent magnet synchronous motor is set to open circuit, and the excitation of the power supply is set to 0. The internal magnetic field is established by the permanent magnet to simulate the dynamic characteristics of the permanent magnet synchronous motor under no-load operation.

[0034] In a preferred embodiment, the step (4) further comprises:

[0035] Perform electromotive force simulation of permanent magnet synchronous motor under no-load operation.

[0036] In another preferred embodiment, the method further comprises:

[0037] (5) The Rmxprt model is imported into a new Maxwell 2D module again. The power source is selected as a voltage source and the initial current is 0A to simulate the load-carrying operation characteristics of the permanent magnet synchronous motor.

[0038] In a further preferred embodiment, the step (5) further comprises:

[0039] Perform air gap magnetic field simulation of permanent magnet synchronous motor.

[0040] In a more preferred embodiment, the step (5) further comprises:

[0041] The matrix change law simulation is performed when the permanent magnet synchronous motor is operating at full load.

[0042] In practical applications, after determining the key parameter characteristics of a permanent magnet synchronous motor, the established mathematical model of the permanent magnet synchronous motor is used to design the motor's magnetic circuit using the RMxprt module. The corresponding module is called to select the motor model, and the motor's physical parameters and rated data are input. The RMxprt model is then exported directly to the Maxwell 2D module. Various material properties are set, vector boundary conditions are added, and the excitation source is configured. In Maxwell 2D, the stator winding of the permanent magnet synchronous motor is set to open circuit, and the power supply excitation is set to zero. The permanent magnets establish an internal magnetic field, thereby simulating the dynamic characteristics of the permanent magnet synchronous motor under no-load operation.

[0043] 1) Simulation of motor no-load running characteristics

[0044] In Maxwell 2D, the stator winding of the permanent magnet synchronous motor is disconnected, and the power supply excitation is set to zero. The permanent magnets create an internal magnetic field, thus simulating the dynamic characteristics of the permanent magnet synchronous motor in no-load operation. The magnetic field characteristics of the permanent magnet synchronous motor in no-load operation are shown in Figure 2.

[0045] from Figure 2a and 2b It can be seen that in the no-load operating characteristics of a permanent magnet synchronous motor, the magnetic lines of force are mostly concentrated in the stator area close to the permanent magnets, and the motor itself has very little magnetic leakage. The magnetic flux is mostly concentrated in the stator tooth space and the stator area close to the permanent magnets. In the no-load operating state, the no-load back EMF is actually generated by the permanent magnets, whose magnetic flux is formed by the interaction of the internal armature windings.

[0046] The no-load back electromotive force simulation results are as follows Figure 3 As shown. Figure 3 It can be seen that the no-load back electromotive force is the electromotive force generated by the permanent magnet of the motor when no load is applied. The magnetic flux of the permanent magnet and the armature winding are intertwined. The back electromotive force of the three phases is 120° apart in sequence. The entire fluctuation is sawtooth-shaped, and the size of the internal magnetic field cannot be adjusted by excitation. Therefore, in the later design process of the permanent magnet synchronous motor, it is necessary to focus on optimizing the structural design, continuously optimize the structural form of the permanent magnet synchronous motor and the internal magnetic field distribution, so as to ensure that the permanent magnet synchronous motor runs smoothly and reliably in the no-load state.

[0047] 2) Simulation of motor full-load operation characteristics

[0048] The permanent magnet synchronous motor running under load means that the permanent magnet synchronous motor is running at rated power. Import Rmxprt into a new Maxwell 2D again. At this time, the power supply can be selected as a voltage source, and the initial current is 0A. The following can be obtained: Figure 4a and 4b The load operation characteristics of the permanent magnet synchronous motor are shown in FIG.

[0049] from Figure 4a It can be seen that when the permanent magnet synchronous motor is running under external load, the magnetic field line distribution shows a trend of spreading from the center to the outside. The magnetic field distribution under rated operation is very different from the actual no-load operation, and it is the superposition of the armature current and the permanent magnet magnetic field. Figure 4b It can be seen that when the permanent magnet synchronous motor is under load, the magnetic lines of force at this time tend to diverge from the middle to the surrounding areas, and the distribution pattern of the magnetic lines of force at 3 o'clock, 6 o'clock, 9 o'clock and 12 o'clock is the same. The distribution of the magnetic lines of force is relatively uniform and the direction is relatively reasonable.

[0050] By simulating the dynamic characteristics of the permanent magnet synchronous motor with load, the variation law of the air gap magnetic field can be obtained. The air gap magnetic field of the permanent magnet synchronous motor is as follows: Figure 5 As shown. Figure 5 It can be seen that the air gap magnetic field of the permanent magnet synchronous motor is entirely provided by permanent magnets. As the load changes, the operating point of the stator armature will change on the hysteresis loop. The increase in the air gap magnetic field will cause the amplitude of the induced electromotive force to decrease. The reduction in the cogging torque will directly affect the tooth flux density value, and the decrease in the flux density value will cause the power factor of the motor to decrease.

[0051] The torque change of permanent magnet synchronous motor under load is as follows: Figure 6 As shown. Under full-load operation, the permanent magnet synchronous motor has a small torque fluctuation, but exhibits large torque fluctuations at the moment of startup. The maximum torque is reached within 0.2 seconds, and after 0.5 seconds, the torque stabilizes, fluctuating between 2.5 and 7.5 N / m. As the speed increases, the torque corresponding table shows a rapid increase, and the torque fluctuation amplitude remains constant at 5 N / m. Simulation shows that the induced voltage at rated load is smoother than the no-load back EMF. The curve shows that the motor runs smoothly at startup without significant speed fluctuations.

[0052] In summary, to address the problem of permanent magnet synchronous motors being highly susceptible to external interference, which can lead to complex dynamic characteristics of the internal magnetic field, this study explored the dynamic characteristics of permanent magnet synchronous motors, established a Maxwell mathematical model for permanent magnet synchronous motors, and numerically simulated the motors using the finite element method. The results showed that under no-load conditions, the torque fluctuations exhibited a sawtooth pattern, and the magnitude of the internal magnetic field could not be adjusted through excitation. Under full-load operation, the permanent magnet synchronous motor's magnetic lines of force were evenly distributed, and the torque reached its maximum value within 0.2 seconds. After 0.5 seconds, the torque stabilized, fluctuating between 2.5 and 7.5 N / m. The operating speed was stable with minimal fluctuations.

[0053] The invention's Maxwell-based permanent magnet synchronous motor magnetic field simulation method uses finite element analysis to simulate the permanent magnet synchronous motor's magnetic field. A Maxwell mathematical model is constructed, and numerical simulation analysis is performed using Maxwell to derive the no-load and rated load operating characteristics of the permanent magnet synchronous motor. The simulation results verify the starting characteristics and dynamic performance of the permanent magnet synchronous motor's magnetic field, laying the foundation for future optimization of the permanent magnet synchronous motor.

[0054] In this specification, the present invention has been described with reference to specific embodiments thereof. However, it will be apparent that various modifications and variations may be made without departing from the spirit and scope of the present invention. Accordingly, the specification and drawings are to be regarded as illustrative rather than restrictive.

Claims

1. A permanent magnet synchronous motor magnetic field simulation method based on Maxwell, characterized in that: The following steps are involved: (1) Determine the parameter characteristics of the permanent magnet synchronous motor and build a mathematical model of the permanent magnet synchronous motor; (2) Use the RMxprt module to design the magnetic circuit of the motor, call the corresponding module to select the motor model, input the physical parameters of the motor and set the rated data of the motor to obtain the RMxprt model; (3) Export the RMxprt model directly to the Maxwell 2D module, set various material properties, add vector boundary conditions and set the excitation source; (4) In Maxwell 2D, the stator winding of the permanent magnet synchronous motor is set to open circuit, and the excitation of the power supply is set to 0. The internal magnetic field is established by the permanent magnet to simulate the dynamic characteristics of the permanent magnet synchronous motor under no-load operation.

2. The Maxwell-based permanent magnet synchronous motor magnetic field simulation method according to claim 1, characterized in that: The step (4) further comprises: Perform electromotive force simulation of permanent magnet synchronous motor under no-load operation.

3. The Maxwell-based permanent magnet synchronous motor magnetic field simulation method according to claim 1, characterized in that: The method further includes: (5) The Rmxprt model is imported into a new Maxwell 2D module again. The power source is selected as a voltage source and the initial current is 0A to simulate the load-carrying operation characteristics of the permanent magnet synchronous motor.

4. The Maxwell-based permanent magnet synchronous motor magnetic field simulation method according to claim 3, characterized in that: The step (5) further comprises: Perform air gap magnetic field simulation of permanent magnet synchronous motor.

5. The Maxwell-based permanent magnet synchronous motor magnetic field simulation method according to claim 4, characterized in that: The step (5) further comprises: The matrix change law simulation is performed when the permanent magnet synchronous motor is operating at full load.

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