A deep understanding of the spectral gain characteristics of optical parametric oscillators (OPOs) and optical parametric amplifiers (OPAs) is important for a highly efficient optical parametric conversion. We numeric...A deep understanding of the spectral gain characteristics of optical parametric oscillators (OPOs) and optical parametric amplifiers (OPAs) is important for a highly efficient optical parametric conversion. We numerically calculated the spectral gain characteristics of a quasi-phase-matching (QPM) parametric conversion process using the periodically poled 6% (mol/mol) MgO doped LiNbO3 (PPMgLN) as the nonlinear crystal. In the simulation we utilized the approach of a transformative matrix of the periodically poled nonlinear medium, which results from the small-signal approximation of three-wave mixed nonlinear equations. Numerical simulation results show that: (1) The full width at half maximum (FWHM) of the spectral gain of the parametric process becomes wider with the increase of parametric wavelength and reaches the maximum at degeneration; (2) The gain coefficient decreases gradually with the increase of parametric wavelength; (3) The spectral gain bandwidth decreases correspondingly with the increase of the nonlinear material length; (4) There exists an optimal parametric wavelength band, which is most suitable for the high gain parametric conversion when pumped by a laser source with a wide wavelength band, such as the high power fiber laser.展开更多
传统固定增益电流超前角探测最大转矩电流比(Fixed-Gain Current Vector Angle Detection Maximum Torque Per Ampere,FGAD-MTPA)算法以转矩的偏导数作为电流超前角搜索的自增量,对负载工况变化具有较高的敏感度。为保持负载工况变化时M...传统固定增益电流超前角探测最大转矩电流比(Fixed-Gain Current Vector Angle Detection Maximum Torque Per Ampere,FGAD-MTPA)算法以转矩的偏导数作为电流超前角搜索的自增量,对负载工况变化具有较高的敏感度。为保持负载工况变化时MTPA状态收敛的一致性,文中提出双变量自适应增益(Double-Variable Adaptive Gain Current Vector Angle Detection,DV-AGAD)的MTPA算法。该算法以β-β_(MTPA)作为超前角自增量,实现最优超前角的迭代。文中提出单变量自适应增益(Single-Variable Adaptive Gain Current Vector Angle Detection,SV-AGAD)的MTPA算法来提高算法动态收敛速度,减轻算法复杂度并减低超调量。根据Lyapunov稳定性理论可知,该控制系统稳定。建立永磁辅助同步磁阻电机(Permanent Magnet Auxiliary Synchronous Reluctance Motor,PMASynRM)矢量控制系统仿真模型,将SV-AGAD-MTPA算法与其他算法进行对比分析。结果表明,新型MTPA算法在加减速、加减载情况下表现良好,同时降低了参数敏感性。展开更多
基金supported by the National Natural Science Foundation of China (No. 60778001)the National Basic Research Program (973) of China (No. 2007CB307003)
文摘A deep understanding of the spectral gain characteristics of optical parametric oscillators (OPOs) and optical parametric amplifiers (OPAs) is important for a highly efficient optical parametric conversion. We numerically calculated the spectral gain characteristics of a quasi-phase-matching (QPM) parametric conversion process using the periodically poled 6% (mol/mol) MgO doped LiNbO3 (PPMgLN) as the nonlinear crystal. In the simulation we utilized the approach of a transformative matrix of the periodically poled nonlinear medium, which results from the small-signal approximation of three-wave mixed nonlinear equations. Numerical simulation results show that: (1) The full width at half maximum (FWHM) of the spectral gain of the parametric process becomes wider with the increase of parametric wavelength and reaches the maximum at degeneration; (2) The gain coefficient decreases gradually with the increase of parametric wavelength; (3) The spectral gain bandwidth decreases correspondingly with the increase of the nonlinear material length; (4) There exists an optimal parametric wavelength band, which is most suitable for the high gain parametric conversion when pumped by a laser source with a wide wavelength band, such as the high power fiber laser.
文摘传统固定增益电流超前角探测最大转矩电流比(Fixed-Gain Current Vector Angle Detection Maximum Torque Per Ampere,FGAD-MTPA)算法以转矩的偏导数作为电流超前角搜索的自增量,对负载工况变化具有较高的敏感度。为保持负载工况变化时MTPA状态收敛的一致性,文中提出双变量自适应增益(Double-Variable Adaptive Gain Current Vector Angle Detection,DV-AGAD)的MTPA算法。该算法以β-β_(MTPA)作为超前角自增量,实现最优超前角的迭代。文中提出单变量自适应增益(Single-Variable Adaptive Gain Current Vector Angle Detection,SV-AGAD)的MTPA算法来提高算法动态收敛速度,减轻算法复杂度并减低超调量。根据Lyapunov稳定性理论可知,该控制系统稳定。建立永磁辅助同步磁阻电机(Permanent Magnet Auxiliary Synchronous Reluctance Motor,PMASynRM)矢量控制系统仿真模型,将SV-AGAD-MTPA算法与其他算法进行对比分析。结果表明,新型MTPA算法在加减速、加减载情况下表现良好,同时降低了参数敏感性。
