The problem of sonar signal waveform design to detect a high-speed small target in an underwater environment is discussed. From theoretical analysis, time-frequency hop signal is regarded as the most suitable signal w...The problem of sonar signal waveform design to detect a high-speed small target in an underwater environment is discussed. From theoretical analysis, time-frequency hop signal is regarded as the most suitable signal waveform in this application. To get precise target parameter estimation ability, the signal should have high range-Doppler resolution performance. The results of signal analysis show that hop signal with frequency serial coding as Costas array has sharp ambiguity characteristic, so it can be used in an active sonar system to detect a high speed small target. A scheme of frequency coding is also presented.展开更多
在传统控制方式下,柔性直流输电(voltage source converter based high voltage direct current,VSC-HVDC)系统换流站难以有效参与电网动态调节,而虚拟同步电机技术通过合适的控制设计使得换流器单元能够为系统提供惯性支撑,已引起广泛...在传统控制方式下,柔性直流输电(voltage source converter based high voltage direct current,VSC-HVDC)系统换流站难以有效参与电网动态调节,而虚拟同步电机技术通过合适的控制设计使得换流器单元能够为系统提供惯性支撑,已引起广泛关注。首先结合VSC-HVDC系统数学模型,分析换流站等效为同步电机的可行性,给出基于虚拟同步电机技术的换流站控制方案。其次,针对整流侧换流站,在动态过程中将逆变侧等效为一个恒功率负载,建立虚拟同步电机内环和电压外环的小信号数学模型,分析并给出一种系统化的控制参数设计方法。最后,通过仿真分析验证文中理论分析的正确性和参数设计方法的有效性。展开更多
文摘The problem of sonar signal waveform design to detect a high-speed small target in an underwater environment is discussed. From theoretical analysis, time-frequency hop signal is regarded as the most suitable signal waveform in this application. To get precise target parameter estimation ability, the signal should have high range-Doppler resolution performance. The results of signal analysis show that hop signal with frequency serial coding as Costas array has sharp ambiguity characteristic, so it can be used in an active sonar system to detect a high speed small target. A scheme of frequency coding is also presented.
文摘在传统控制方式下,柔性直流输电(voltage source converter based high voltage direct current,VSC-HVDC)系统换流站难以有效参与电网动态调节,而虚拟同步电机技术通过合适的控制设计使得换流器单元能够为系统提供惯性支撑,已引起广泛关注。首先结合VSC-HVDC系统数学模型,分析换流站等效为同步电机的可行性,给出基于虚拟同步电机技术的换流站控制方案。其次,针对整流侧换流站,在动态过程中将逆变侧等效为一个恒功率负载,建立虚拟同步电机内环和电压外环的小信号数学模型,分析并给出一种系统化的控制参数设计方法。最后,通过仿真分析验证文中理论分析的正确性和参数设计方法的有效性。