To reduce additional mass, this work proposes a nonlinear energy sink(NES)with an inertial amplifier(NES-IA) to control the vertical vibration of the objects under harmonic and shock excitations. Moreover, this paper ...To reduce additional mass, this work proposes a nonlinear energy sink(NES)with an inertial amplifier(NES-IA) to control the vertical vibration of the objects under harmonic and shock excitations. Moreover, this paper constructs pure nonlinear stiffness without neglecting the gravity effect of the oscillator. Both analytical and numerical methods are used to evaluate the performance of the NES-IA. The research findings indicate that even if the actual mass is 1% of the main oscillator, the NES-IA with proper inertia angles and mass distribution ratios can still effectively attenuate the steady-state and transient responses of the main oscillator. Nonlinear stiffness and damping also have important effects. Due to strongly nonlinear factors, the coupled system may exhibit higher branch responses under harmonic excitation. In shock excitation environment, the NES-IA with a large dynamic mass can trigger energy capture of both main resonance and high-frequency resonance. Furthermore, the comparison with the traditional NES also confirms the advantages of the NES-IA in overcoming mass dependence.展开更多
介绍了大功率高效率功率放大器(功放)在实际设计时面临的晶体管寄生效应问题,并通过引入晶体管封装寄生模型对本征端阻抗进行等效迁移,进而提高了输出匹配网络设计的便捷性。提出一种基于紧凑型微带谐振单元的电路设计方法及其传输线拓...介绍了大功率高效率功率放大器(功放)在实际设计时面临的晶体管寄生效应问题,并通过引入晶体管封装寄生模型对本征端阻抗进行等效迁移,进而提高了输出匹配网络设计的便捷性。提出一种基于紧凑型微带谐振单元的电路设计方法及其传输线拓扑结构,其中,紧凑型微带谐振单元的作用是提供功放在三次谐波所需的开路点,从而通过调谐传输线满足相应阻抗条件。其优点还包括:基波频率下插入损耗低、效率高;实际物理尺寸小,可满足小型化需求。为了更好地验证上述理论,基于10 W GaN HEMT CGH40010F晶体管和大功率高效率E/F开关类功放在2.2 GHz的工作频率下进行了具体的电路设计。仿真结果表明,该款功放的最大功率附加效率可达78.4%,最大输出功率可达40.1 dBm,功率增益为12.1 dB。展开更多
为了能够对磁共振功放的强分叉非线性进行精确建模,提出一种时间功率混合分段模型。时间功率混合分段模型是针对磁共振功放的激励为辛格脉冲信号时的精确非线性模型。所提出的模型基于辛格脉冲信号的特点进行时域和幅度域分段,从而能够...为了能够对磁共振功放的强分叉非线性进行精确建模,提出一种时间功率混合分段模型。时间功率混合分段模型是针对磁共振功放的激励为辛格脉冲信号时的精确非线性模型。所提出的模型基于辛格脉冲信号的特点进行时域和幅度域分段,从而能够对磁共振功放的分叉非线性进行精确建模。采用辛格脉冲信号作为测试信号,测试信号的占空比为5%,设计输出峰值为18 k W的1.5 T磁共振功放（工作频率63.89 MHz）作为测试功放进行模型的有效性验证。实测磁共振功放和模型的AM/AM和AM/PM曲线的比较结果表明,时间功率混合分段模型能够对磁共振功放的分叉非线性进行精确建模。同时,所提出模型的归一化均方误差（NMSE）比记忆多项式、广义记忆多项式模型和时分多项式模型分别提高10.7 d B,10.3 d B和14.7 d B。展开更多
基金Project supported by the National Natural Science Foundation of China (Nos. 12172014 and11972050)the Key Laboratory of Vibration and Control of Aero-Propulsion System (Northeastern University),Ministry of Education of China (No. VCAME 202004)。
文摘To reduce additional mass, this work proposes a nonlinear energy sink(NES)with an inertial amplifier(NES-IA) to control the vertical vibration of the objects under harmonic and shock excitations. Moreover, this paper constructs pure nonlinear stiffness without neglecting the gravity effect of the oscillator. Both analytical and numerical methods are used to evaluate the performance of the NES-IA. The research findings indicate that even if the actual mass is 1% of the main oscillator, the NES-IA with proper inertia angles and mass distribution ratios can still effectively attenuate the steady-state and transient responses of the main oscillator. Nonlinear stiffness and damping also have important effects. Due to strongly nonlinear factors, the coupled system may exhibit higher branch responses under harmonic excitation. In shock excitation environment, the NES-IA with a large dynamic mass can trigger energy capture of both main resonance and high-frequency resonance. Furthermore, the comparison with the traditional NES also confirms the advantages of the NES-IA in overcoming mass dependence.
文摘介绍了大功率高效率功率放大器(功放)在实际设计时面临的晶体管寄生效应问题,并通过引入晶体管封装寄生模型对本征端阻抗进行等效迁移,进而提高了输出匹配网络设计的便捷性。提出一种基于紧凑型微带谐振单元的电路设计方法及其传输线拓扑结构,其中,紧凑型微带谐振单元的作用是提供功放在三次谐波所需的开路点,从而通过调谐传输线满足相应阻抗条件。其优点还包括:基波频率下插入损耗低、效率高;实际物理尺寸小,可满足小型化需求。为了更好地验证上述理论,基于10 W GaN HEMT CGH40010F晶体管和大功率高效率E/F开关类功放在2.2 GHz的工作频率下进行了具体的电路设计。仿真结果表明,该款功放的最大功率附加效率可达78.4%,最大输出功率可达40.1 dBm,功率增益为12.1 dB。
文摘为了能够对磁共振功放的强分叉非线性进行精确建模,提出一种时间功率混合分段模型。时间功率混合分段模型是针对磁共振功放的激励为辛格脉冲信号时的精确非线性模型。所提出的模型基于辛格脉冲信号的特点进行时域和幅度域分段,从而能够对磁共振功放的分叉非线性进行精确建模。采用辛格脉冲信号作为测试信号,测试信号的占空比为5%,设计输出峰值为18 k W的1.5 T磁共振功放（工作频率63.89 MHz）作为测试功放进行模型的有效性验证。实测磁共振功放和模型的AM/AM和AM/PM曲线的比较结果表明,时间功率混合分段模型能够对磁共振功放的分叉非线性进行精确建模。同时,所提出模型的归一化均方误差（NMSE）比记忆多项式、广义记忆多项式模型和时分多项式模型分别提高10.7 d B,10.3 d B和14.7 d B。
