4 results about "Frequency instability" patented technology

This invention discloses an ultra-high stability laser system based on dual-path independent composite frequency stabilization and sum-frequency modulation, belonging to the field of precision laser spectroscopy and frequency control technology. The system includes two seed lasers (1560 nm and 1064 nm), a dual-wavelength common-cavity ultra-stable module, two acousto-optic frequency shift and dual-reference absolute frequency stabilization modules, and a nonlinear sum-frequency modulation (SFG) module. Full-time-scale frequency noise suppression is achieved through a three-stage cascaded closed loop consisting of a MHz fast loop, a kHz slow loop, and a Hz extremely slow loop. An acousto-optic modulator is placed in the sampling optical path fed into the ultra-stable cavity, and physical decoupling of the fast and slow loops is achieved through radio frequency bridging. The extremely low-frequency error signal detected by NICE-OHMS is fed back to the PPMgOLN crystal temperature or AOM driving frequency to compensate for the thermally induced drift of the nonlinear crystal. The system ultimately outputs a 633 nm laser power of not less than 50 mW, with a short-term frequency instability better than 5 × 10⁻⁶ mW. ‑15 @1 s.

The invention discloses a hybrid energy storage inertia support optimization method based on real-time frequency change rate dynamic decoupling distribution, and the method comprises the steps: monitoring the power grid frequency change rate of a target hybrid energy storage system in real time, and generating a total inertia power demand; based on the total inertia power demand, determining a super capacitor power distribution weight; obtaining an optimized power value of the super capacitor and an optimized power value of the energy storage battery according to the constructed objective function; based on the optimized power value of the super capacitor and the power value of the energy storage battery, correcting the power distribution weight of the super capacitor; and generating a super-capacitor inertia time constant and an energy storage battery inertia time constant based on the corrected super-capacitor power distribution weight. According to the method, the problem of frequency instability caused by insufficient inertia of a high-proportion new energy power grid is solved; the stability level of the power grid frequency is remarkably improved, the service life of the energy storage battery is greatly prolonged, and the whole life cycle operation and maintenance cost is reduced.

The invention belongs to the technical field of cable fault positioning, and particularly relates to an intelligent cable fault positioning method and system based on a wave reflection method, and the method comprises the steps: injecting a pulse signal into a to-be-detected cable, and obtaining a time domain reflection discrete sequence according to a sampling cut-off moment determined based on a minimum theoretical wave velocity; calculating a heuristic propagation wave velocity according to the maximum reflection pulse in the sequence, and determining a real-time attenuation constant and a real-time propagation wave velocity based on the rationality of the heuristic propagation wave velocity; variational mode decomposition is carried out on the sequence, and a kurtosis screening index based on a central moment is utilized to select a fault sensitive mode component; correcting the Talbot energy of the modal component in combination with a real-time attenuation constant and a local frequency instability index to obtain a time-varying frequency weighted energy spectrum; and calculating a fault positioning distance according to the energy spectrum peak moment. According to the invention, through adaptive adjustment of the wave velocity parameter and the time-varying frequency weighted energy spectrum, accurate positioning of the aging cable and the fault in a complex noise environment is realized.

The present application belongs to the technical field of power system restoration control, and discloses a power coordination control method of a hybrid energy storage auxiliary black start system and related devices. The method obtains the total active power demand of the black start system, decomposes it into three time scale components of fundamental wave, medium frequency and high frequency, dynamically allocates it to lithium batteries and super capacitors, and then corrects the allocated power based on temperature, operation time and rated parameters. Finally, the frequency change rate and the DC voltage change rate are calculated according to the actual power instruction and the system parameters, and the controller outputs the control quantity. The method overcomes the contradiction between the energy and the power density of a single power source, cooperatively improves the response speed and the continuous power supply capacity, effectively suppresses the voltage frequency instability risk caused by the load input, and significantly improves the reliability and efficiency of the black start through the improved hybrid energy storage coordination control.