Based on electromagnetics and mechanics, electromechanical coupled dynamic equations for the drive were developed. Using method of perturbation, free vibrations of the mechanical system under electric disturbance were...Based on electromagnetics and mechanics, electromechanical coupled dynamic equations for the drive were developed. Using method of perturbation, free vibrations of the mechanical system under electric disturbance were investigated. The forced responses of the mechanical system to mechanical excitation under electric disturbance were also presented. It is known that for the system with electric disturbance, as time grows, beat occurs. When electric disturbing frequency is near to the natural frequencies of the mechanical system or their integer multiple, resonance vibrations occur. The forced responses of the mechanical system to mechanical excitation under electric disturbance are compound vibrations decided by mechanical excitation, electric disturbance and parameters of the system. The coupled resonance vibration caused by electric disturbance and mechanical excitation was discussed as well. The conditions under which above coupled resonance occurs were presented. The results show that when the difference of the excitation frequency and the perturbation frequency is equal to some order of natural frequency, coupled resonance vibrations occur.展开更多
In order to achieve high precision measurement of inductance in a wide frequency range,a method of inductance measurement based on double-excitation auto-balancing bridge is proposed.In this method,the direct digital ...In order to achieve high precision measurement of inductance in a wide frequency range,a method of inductance measurement based on double-excitation auto-balancing bridge is proposed.In this method,the direct digital synthesizer(DDS)as signal generator is used as the bridge excitation source,and the bridge is automatically balanced by adjusting and measuring the voltage ratio.Using standard resistors,the system can achieve high precision measurement of four-terminal pair inductors in the frequency range of 100Hz-100kHz.Aiming at the low efficiency of bridge balancing,an iterative balancing algorithm based on the steepest descent method is proposed.In order to suppress the interference caused by the initial phase change and non-integer periodic sampling,the high-precision measurement of the complex impedance of inductance is realized based on the all-phase fast Fourier transform(apFFT).Finally,the corresponding measurement system is built and the inductance measurement experiment is carried out.The experimental results show that the relative error of the system for inductance measurement can be as low as 0.009%,and the optimal relative measurement uncertainty of the system can reach 9.89×10^(-4)compared with 5×10^(-5)of commercial impedance analyzer.展开更多
基金Project(51075350)supported by the National Natural Science Foundation of China
文摘Based on electromagnetics and mechanics, electromechanical coupled dynamic equations for the drive were developed. Using method of perturbation, free vibrations of the mechanical system under electric disturbance were investigated. The forced responses of the mechanical system to mechanical excitation under electric disturbance were also presented. It is known that for the system with electric disturbance, as time grows, beat occurs. When electric disturbing frequency is near to the natural frequencies of the mechanical system or their integer multiple, resonance vibrations occur. The forced responses of the mechanical system to mechanical excitation under electric disturbance are compound vibrations decided by mechanical excitation, electric disturbance and parameters of the system. The coupled resonance vibration caused by electric disturbance and mechanical excitation was discussed as well. The conditions under which above coupled resonance occurs were presented. The results show that when the difference of the excitation frequency and the perturbation frequency is equal to some order of natural frequency, coupled resonance vibrations occur.
基金National Key Research and Development Plan Project(No.2020YFB2010800)National Natural Science Foundation of China(Nos.61905175,51775377,61971307)+4 种基金Fok Ying Tung Education Foundation(No.171055)China Postdoctoral Science Foundation(No.2020M680878)Guangdong Province Key Research and Development Plan Project(No.2020B0404030001)Tianjin Science and Technology Plan Project(No.20YDTPJC01660)Project of Foreign Affairs Committee of China Aviation Development Sichuan Gas Turbine Research Institute(Nos.GJCZ-2020-0040,GJCZ-2020-0041)。
文摘In order to achieve high precision measurement of inductance in a wide frequency range,a method of inductance measurement based on double-excitation auto-balancing bridge is proposed.In this method,the direct digital synthesizer(DDS)as signal generator is used as the bridge excitation source,and the bridge is automatically balanced by adjusting and measuring the voltage ratio.Using standard resistors,the system can achieve high precision measurement of four-terminal pair inductors in the frequency range of 100Hz-100kHz.Aiming at the low efficiency of bridge balancing,an iterative balancing algorithm based on the steepest descent method is proposed.In order to suppress the interference caused by the initial phase change and non-integer periodic sampling,the high-precision measurement of the complex impedance of inductance is realized based on the all-phase fast Fourier transform(apFFT).Finally,the corresponding measurement system is built and the inductance measurement experiment is carried out.The experimental results show that the relative error of the system for inductance measurement can be as low as 0.009%,and the optimal relative measurement uncertainty of the system can reach 9.89×10^(-4)compared with 5×10^(-5)of commercial impedance analyzer.
