Study on the difference of performance of permanent magnet motor between soft magnetic composite material and silicon steel sheet material
Zhao Guoxin and Kong Decai, researchers of the School of Electrical Engineering of Shenyang University of Technology, wrote in the Journal of Electrotechnical Engineering in 2018 that soft magnetic composite materials are pressed from metal powder particles with insulating surface and have small eddy current loss. The characteristics of the same-sex have been applied in recent years, but their hysteresis loss is large and the magnetic permeability is low. Therefore, the specific application and the specific difference with the performance of the silicon steel sheet need further research.
In this paper, the magnetic properties of soft magnetic composites are first tested by the annular sample method, and the no-load magnetization curve and loss data at different frequencies are obtained. Then, in order to compare and analyze the difference between the soft magnetic composite material and the silicon steel sheet material in the motor application, two permanent magnet synchronous motors were designed using soft magnetic composite material and silicon steel sheet respectively, and the magnetic field, iron loss and iron of the two materials were analyzed and calculated. The law of variation at different frequencies. Finally, the difference between the application of the two materials in the permanent magnet motor was mastered by the prototype test, the accuracy of the calculation was verified, and the application range of the soft magnetic composite material was summarized.
SoftMagnetic Composite Materials (SMC) are obtained by powder metallurgy technology for pre-mixing high-purity iron powder with insulating layer and organic material. In recent years, it has been widely studied and applied in the field of motors and other fields [1] -4]. The characteristics of SMC material can be directly molded and molded, which makes the structure and electromagnetic design of the motor more flexible and novel. It opens up a new direction for the application and development of the motor and attracts many researchers [5-7].
SMC materials have high resistivity and low eddy current loss, making SMC materials more suitable for use in high-frequency motors, but SMC materials also have some inevitable shortcomings, such as low magnetic permeability and large hysteresis loss. Therefore, the application rules and characteristics of SMC materials in motors still need further research.
In [7], the SMC material motor has been fully studied. It is found that the motor performance of SMC and silicon steel sheet materials is different at different speeds and different output powers. When the motor is made at 1000r/min and 625r/min, SMC The material motor has low efficiency. When the motor current is 4A, the efficiency is 28% and 34.7% lower than that of the silicon steel sheet motor. When the voltage is above 1500r/min, the SMC material motor efficiency is higher, which is 3% higher than that of the silicon steel sheet motor.
Literature [8] also compared the efficiency of induction motor made of SMC material and silicon steel sheet material. It was found that the same power supply voltage, SMC material motor efficiency is 7% lower, but SMC motor is more sensitive to power supply voltage, after reducing the power supply voltage, SMC motor efficiency It can be improved from 220V to 180V, and the efficiency is increased by 4.7%. However, the efficiency of the SMC motor is lower than that of the silicon steel sheet motor. When the power supply voltage is 220V and 180V, it is 10.3% and 6.7% lower, respectively.
Although the SMC material already has a certain research and application basis, its characteristics, occasions, laws and characteristics of the silicon steel sheet at different operating frequencies still need to be studied.
In order to study the characteristics of SMC materials and analyze the difference between them and traditional silicon steel sheets, this paper firstly tests the magnetic properties of SMC materials of Hoomas model Somaloy700, and compares them with the commonly used silicon steel sheet DW470 with thickness of 0.5mm. Two permanent magnet synchronous motors of the same size and parameters were designed with SMC material and DW470 as the core material. Magnetic field analysis and loss calculation were performed on the two motors, and the characteristics and differences of the prototypes made by the two materials were analyzed. Finally, the prototype was fabricated and Tests were made to show the difference in performance between the two prototypes.
Through the analysis and comparison of this paper, the characteristics of SMC materials can be summarized, and the difference of motor performance between SMC material and silicon steel sheet material and the application of SMC material can be obtained, which can summarize the rules for the application of SMC materials in the motor.
in conclusion
In order to compare the difference of performance between silicon steel sheet material and soft magnetic composite material in the motor, two permanent magnet synchronous motors with SMC material and DW470 as core are designed and manufactured. Combined with finite element calculation and experimental research, the following results are obtained. in conclusion:
1) The magnetic properties of SMC materials were tested based on the ring sample method. The magnetization curves and loss curves of SMC materials were obtained. Compared with DW470, the magnetic permeability of SMC materials was found to be low. The increase is higher than the loss. 400Hz is a key frequency point. When the frequency is below 400Hz, the loss of silicon steel sheet material is smaller than that of SMC material. When the frequency is higher than 400Hz, the specific loss of soft magnetic composite material is lower than DW470. material.
2) According to the no-load experiment, the back electromotive force of the SMC prototype is smaller than that of the DW470 motor, which is consistent with the theoretical calculation, which verifies the low magnetic permeability of the SMC material. The load test of the two prototypes shows that the DW470 material motor is highly efficient at frequencies below 400 Hz, but as the frequency increases, the difference in prototype efficiency between the two materials is getting smaller and smaller. At 400 Hz, both The frequency is basically the same, which is consistent with the theoretical calculation. It shows that the SMC permanent magnet synchronous motor has good performance at medium and high frequency, which can offset the shortcomings of low magnetic permeability and hysteresis loss, and has a good application prospect. .
3) Because the SMC material is fragile, the thickness should be increased appropriately during design, and the sharp edges and corners should be avoided as much as possible. After processing, it should be coated with glue or epoxy resin to increase the strength of the core and prevent “slag”.
