Magnetic field modulated permanent magnet linear generator improves the design point speed and electromotive force of the motor by utilizing the magnetic modulation effect,thereby improving the power density of the motor,especially suit-able for wave energy generation.Based on the design input,a dual-mover magnetic field modulated permanent magnet linear genera-tor design scheme was completed,and the air gap magnetic field,static characteristics,open-circuit performance,and load characteristics of the motor were analyzed and calculated using finite element method.The computational results demonstrate the rationality and correctness of the design.In order to reduce the thrust fluctuation,the speed ratio,relative width of the modulation unit,and thickness of the modulation unit were optimized,providing reference for the design of dual-mover perma-nent magnet linear generator.
Using a permanent magnet DC motor as the test object,under the same test conditions,the motor efficiency was tested twice using a power analyzer and a dynamometer with different ranges and accuracies.Analyzed the sources of uncertainty in motor efficiency measurement,described in detail the evaluation process of each uncertainty component,calculated and synthesized the standard uncertainty of motor efficien-cy.Analyzing the evaluation process and results of measurement uncertainty provides a certain reference for selecting instrument equipment when measuring motor efficiency or conducting other inspections.
Aiming at the technical requirements of a high power density servo drive motor for a rotor UAV,through analysis and finite element simulation optimization,it is concluded that the surface-mounted perma-nent magnet rotor structure of the inner rotor is relatively more suitable for balancing power density,efficien-cy,torque ripple and other indicators.Based on this,a servo drive motor with high power density,high effi-ciency and low torque ripple was designed,and the prototype was tested and verified,and its performance index was satisfied with technical requirements.
In response to the shortcomings of traditional magnetic circuit design for resolver,a high-precision modern design method for resolver was studied.Maxwell software was used for finite element simulation of re-solver magnetic circuit,and combined with Matlab software,extreme value sampling and cubic spline inter-polation were used to accurately extract the envelope of output signal,so as to effectively evaluate the sine of output signal;Using multi-angle electromagnetic simulation analysis method and the"forward and reverse tangent method"of the output signal of the resolver,combined with Matlab software,to achieve the calcula-tion of the electrical accuracy of the resolver at all angles,and effectively evaluate the electrical accuracy values of the resolver rotor at different positions.The experimental results were compared with the actual test results of resolver under 8 different base numbers and excitation conditions,proving its effectiveness.
Electrolytic capacitor-less three phase permanent magnet synchronous motor drive system has the advantage of long lifetime,high power density and so on.This paper made a detailed analysis of the basic structure and working principle of the system.The relationship of q axis current and the output power of the inverter was analyzed and q axis current control strategy was given.The simple and valid control strategy of d axis current was given based on DC bus voltage limitation.In order to improve the power factor of the grid side,a notch filter was added to filter the specified harmonic component in the given d-axis voltage.The simulation results show that the control strategy can effectively reduce the input current distortion rate.
