15 results about "Sustained oscillations" patented technology

An optical parametric oscillator and method for generating coherent signal light involve a resonant optical cavity for coherent signal light, and in the cavity a non-parametric gain element for amplifying the coherent signal light to only partially compensate for passive optical roundtrip losses, thereby obtaining lower effective roundtrip losses. A parametric gain element is arranged in the cavity, for converting coherent pump light into coherent signal light through an instantaneous nonlinear optical interaction. The parametric oscillator has means for adjusting an intracavity optical power of the coherent pump light above a threshold value, where the parametric gain is balancing the effective roundtrip losses, thus inducing sustained oscillations of the signal light in the optical cavity. The non-parametric gain element is configured to have a limited non-parametric gain over a gain bandwidth of the parametric gain element, which is less than the passive optical roundtrip losses in the gain bandwidth.

This invention relates to the field of spacecraft attitude control technology, and more particularly to an active phase stabilization control method and system for flexible vibration during agile maneuvers of satellites. Based on a two-level collaborative architecture of primary control on the satellite platform and secondary control on the three-dimensional super-platform, this method addresses the problem of sustained oscillations easily triggered by large flexible appendages after agile maneuvers by designing an active phase stabilization controller. This controller is configured to specifically design the key flexible mode frequencies affecting maneuver stability. Through phase lead compensation, the damping ratio of the system is effectively increased, thereby rapidly suppressing flexible vibrations after maneuver cessation. By distributing the load control torque, after phase stabilization compensation, to each actuator on the three-dimensional super-platform, rapid stabilization of the load direction within seconds is achieved, overcoming the contradiction between rapid maneuvering and ultra-high stability that is difficult to achieve in existing technologies, and meeting the stability requirements of ultra-high resolution imaging.

The application relates to the field of generator cooling, and particularly provides an evaporation cooling system comprising a top-mounted pressure control mechanism and a control method. The application aims to solve the problem that the evaporation cooling system is prone to self-sustained oscillation under the condition that the load of the generator suddenly increases or the cooling mechanism fails. To this end, the evaporation cooling system comprising the top-mounted pressure control mechanism is characterized in that the space of the pressure control body is divided into a pressure stabilizing space and a pressure control space, the size of the pressure stabilizing space is adjustable, and the pressure control space is connected with the exhaust side of the cooling mechanism. When the generator encounters load mutation or the cooling mechanism fails to cause gas accumulation, the exhaust side of the cooling mechanism enters the pressure control space through the first switching element, the size of the pressure control space can be adaptively adjusted according to the gas pressure of the exhaust side of the cooling mechanism, the gas pressure of the exhaust side of the cooling mechanism is reduced, the cooling effect of the stator bar is improved, the flow phase difference between the inlet and the outlet of the stator bar is reduced, and thus the self-sustained oscillation of the evaporation cooling system is avoided.

The invention discloses an anti-vibration protection device for a weighing belt weigher, which belongs to the field of bulk material continuous metering and comprises an upper mounting plate, a lower mounting plate and an anti-vibration protection mechanism arranged between the upper mounting plate and the lower mounting plate. The anti-vibration protection mechanism comprises a protection barrel fixedly connected with the lower mounting plate, a vertical groove formed in the protection barrel, a guide rod fixedly arranged in the vertical groove and a buffer sliding block arranged on the guide rod in a sliding and sleeving mode, and a buffer spring arranged on the guide rod in a sleeving mode is fixedly arranged between the lower end of the buffer sliding block and the bottom wall of the vertical groove; hydraulic dampers are arranged between the lower ends of the buffering sliding blocks and the bottom walls of the vertical grooves. Through cooperation of a protective cylinder, a guide rod, a buffer slide block, a lifting plate, a buffer spring and a hydraulic damper of the anti-vibration protection mechanism, longitudinal vibration can be effectively absorbed, vibration energy can be consumed, continuous oscillation of the scale body is avoided, the operation stability of the weighing bridge and the weighing sensor is greatly improved, the metering error is reduced, and the service life of parts is prolonged.

The invention discloses a back pressure steam turbine rotating speed stabilizing system and method based on cooperative control of double executing mechanisms, belongs to the technical field of thermal power plant thermotechnical automatic control, and aims to solve the problem that the rotating speed of a steam turbine continuously oscillates due to setting of a dead zone in existing two-stage series PID (Proportion Integration Differentiation) control. And a double-execution-mechanism cooperation mechanism of the adjusting valve and the exhaust valve is constructed. An inlet adjusting valve is maintained to control a main channel PIDB and a rotating speed input dead zone of the main channel PIDB, and large-range adjusting stability is ensured; an exhaust valve control auxiliary channel PIDC is added, the input of the exhaust valve control auxiliary channel PIDC is the deviation between a rotating speed set value and an actual value, an exhaust valve adjusting opening degree instruction beta is output, and a dead zone is not set; through a hysteresis comparator and a zero drift filter, PIDC is automatically started to suppress micro-amplitude oscillation when the rotating speed deviation falls into a main channel dead zone. Rotating speed sawtooth wave oscillation in a dead zone is thoroughly eliminated, the bearing abrasion rate is reduced, and meanwhile the hearth negative pressure control precision and the combustion efficiency are improved.

The invention discloses a temperature control system and method for an L + + EDFA Erbium fiber heat preservation box, and relates to the technical field of automatic control, and the system comprises a temperature sensor, a controller, a PWM drive circuit, and a heating sheet in the Erbium fiber heat preservation box. The core lies in that the controller operates an improved PID control algorithm, and the algorithm integrates an integral anti-saturation mechanism and differential item smoothing processing. The method comprises: sampling the temperature of a heating sheet and calculating an error; calculating items P, I and D; pre-calculating the sum of the three items and limiting the output; the key of output limitation is to carry out integral anti-saturation processing, and when the output is saturated, integral accumulation is suspended to prevent an integral item from being saturated; and finally outputting a PWM signal to control the heating power. According to the invention, the problems of overshoot and continuous oscillation caused by residual heat in a thermal hysteresis system in traditional PI control are effectively solved, and rapid, stable and high-precision temperature control in a wide environment temperature range is realized.

The utility model discloses ring shape oscillation circuit and ring shape oscillator, ring shape oscillation circuit includes ring shape oscillation module, and ring shape oscillation module includes 2n+1 head -to -tail cascaded inverter unit, and every inverter unit is correspondingly provided with current pull -up unit and current pull -down unit, and current pull -up unit is connected with first current output end and corresponding inverter unit respectively, and current pull -down unit is connected with second current output end and corresponding inverter unit respectively, and 2n inverter units are connected in the mode that the first end of two adjacent inverter units corresponds and meets, and the second end of another two adjacent inverter units corresponds and meets, starting from the inverter unit of first position, and the connecting end of the inverter unit of last position and current pull -down unit is connected to the connecting end of the inverter unit of first position and current pull -down unit. Because the size of first bias current and second bias current on same inverter unit is different, and the steady state operating point of negative feedback loop is broken down equivalent, thereby continuous oscillation.

The invention provides a low-power-consumption numerically-controlled oscillator, relates to the technical field of integrated circuits, and comprises a resonant cavity module used for generating a high-frequency resonant signal based on a resonator; the input end of the complementary cross-coupled oscillation module is connected with the resonant cavity module, and the complementary cross-coupled oscillation module is used for receiving high-frequency resonant signals and generating continuous oscillation; a capacitor array of the segmented numerical control capacitor tuning module is connected in parallel to two ends of the resonant cavity module and is used for receiving external numerical control signals and changing equivalent capacitance of a resonant network, so that wide-range and high-precision digital tuning is carried out on oscillation frequency; the parasitic oscillation suppression module is integrated in an internal feedback path of the complementary cross-coupled oscillation module and is used for suppressing direct-current positive feedback and attenuating low-frequency loop gain so as to eliminate direct-current locking and low-frequency parasitic oscillation; the input end of the output buffer module is connected with the output node of the complementary cross-coupling oscillation module, and the output buffer module is used for shaping and driving the oscillation signal and then outputting the signal. In the mode, wide tuning, ultra-low power consumption, high stability and high-precision tuning are realized, meanwhile, the phase noise performance and the mass production feasibility are improved, and the strict requirements of the battery-free Internet of Things node are met.

The invention discloses a self-oscillation light source and microwave source based on hybrid integration and photoelectric feedback and a working method of the self-oscillation light source and microwave source. According to the device, an erbium-doped silicon nitride gain waveguide and a lithium tantalate electrooptical modulator are heterogeneously integrated on the same chip, and a high-Q-value optical resonant cavity is formed by the device, a single-mode polarization maintaining optical fiber and a reflector of the single-mode polarization maintaining optical fiber through end face coupling; the microwave feedback loop comprises a photoelectric detector, a narrowband frequency-selecting filter, a phase shifter and a microwave amplifier, and the microwave feedback loop and the optical resonant cavity form a photoelectric interlocking closed oscillation ring through a modulator and a detector. During working, the frequency-selecting filter selects a target microwave frequency, the phase shifter is adjusted to enable feedback microwaves to be synchronous with optical pulses in the cavity, and the system realizes self-sustaining oscillation without an external microwave source and outputs optical pulses with stable repetition frequency and microwave signals with low phase noise at the same time. The invention has the advantages of compact structure, high stability and low noise.

The invention discloses an energy analysis method, system, product and medium. The method comprises the following steps: in an energy analysis simulation process, when a continuous oscillation locking characteristic of a key factor is monitored, firstly identifying a conflict factor with an antagonism relationship; afterwards, target deviation caused by compromise to other factors is quantified by simulating behaviors of each energy analysis factor in a preset compromise decreasing range, and a compromise function of each factor is constructed based on the target deviation; thirdly, combining all compromise functions into a total deviation objective function, and finding an optimal decision variable combination capable of minimizing total deviation by solving the function; and finally, adjusting system operation parameters according to the group of decision variables. By implementing the technical scheme provided by the invention, the operation stability of the energy analysis system is improved under the condition that data oscillation occurs in the energy system.

The invention relates to a damping transportation tool, and relates to the technical field of transportation. Comprising a base, the base comprises a frame-shaped frame and a supporting frame, the supporting frame is arranged in the frame-shaped frame, a supporting table is arranged on the supporting frame through a buffering piece, the supporting table comprises a platform and a connecting frame, and goods are placed on the platform and supported in the moving process. The following problems existing in the packaging and transporting process in the prior art can be solved: the sliding plate is driven by the supporting rod to slide in the cavity filled with hydraulic oil, the hydraulic oil is forced to flow through the through hole in the sliding plate, and impact kinetic energy is efficiently converted and dissipated through the throttling effect of liquid viscous damping. The mechanism not only can absorb energy in the compression stroke, but also can generate reverse damping force in the springback stroke, so that the inherent continuous oscillation problem of a traditional pure spring damping system is remarkably restrained, and the buffering process is more stable and rapid in convergence.

The invention belongs to the technical field of virtual synchronous generators, and discloses a method and a related device for enhancing VSG power oscillation suppression in a weak power grid, and the method comprises the steps: extracting an oscillation frequency component in an angular frequency error through a band-pass filter, and generating an active power oscillation adjustment quantity through inertia adjustment and proportional adjustment; superposing to a main power regulation branch to actively suppress active oscillation; a d-axis voltage deviation and a d-axis current deviation are respectively processed to obtain a first compensation component and a second compensation component, a third compensation component based on a d-axis voltage reference value is combined to calculate a reactive power compensation amount, and the reactive power compensation amount is input into a reactive droop control branch to enhance system damping. By adopting the method, the active and reactive power oscillation amplitudes of the VSG in the weak power grid are remarkably weakened, and the risk of electric energy quality deterioration or instability caused by continuous oscillation is avoided, so that the stable operation capability and the anti-interference performance of the system under the condition of the weak power grid are improved.

The invention relates to the technical field of spacecraft attitude control, in particular to a satellite agile maneuvering flexible vibration active phase stability control method and system. According to the method, on the basis of a two-stage collaborative architecture of satellite platform first-stage control and three-super platform second-stage control, an active phase stability controller is designed for solving the problem that a large-flexibility accessory is prone to causing continuous oscillation after agile maneuvering. The controller is configured to perform specific design on a key flexible modal frequency influencing the maneuvering stability, and equivalently increases the damping ratio of the system through phase lead compensation, so that the flexible vibration after maneuvering stop is quickly suppressed. By distributing the load control torque after phase stabilization compensation to each actuator of the three-super platform for execution, second-level fast stabilization of load pointing is realized, the contradiction that fast maneuvering and ultrahigh stability are difficult to consider in the prior art is overcome, and the requirement of ultrahigh-resolution imaging for stability is met.

Provided in the present invention is a drive planning method for a high-speed motion mechanism. In the present invention, two consecutive drive phases, i.e., a first drive phase and a second drive phase, are planned on the basis of the maximum overshoot of inertial vibration and a vibration duration. The first drive phase is a high-speed and high-acceleration motion drive phase; and the second drive phase is a dynamic low-speed and low-acceleration S-curve drive phase. In the first drive phase in the present invention, high-speed motion is still achieved, ensuring high efficiency of the motion; and by means of setting a certain clearance, overshoot and sustained oscillation of a positioning target that are caused by a high-speed and high-inertia motion are avoided, thereby preventing the motion mechanism from colliding with or damaging the positioning target. In the present invention, the positioning target is reached via the second drive phase, such that overshoot and inertial oscillation at a final target can be avoided, and thus the influence of inertial impact caused by high-speed motion on positioning accuracy can be prevented, so as to realize high-precision positioning. Moreover, the present invention does not prolong the overall positioning operation time, thereby ensuring high efficiency of the overall operation.

The invention belongs to the technical field of semiconductor manufacturing, and particularly relates to a temperature oscillation growth method for improving the uniformity of a GaAs epitaxial layer, which comprises the following steps of: placing a GaAs substrate in an MOCVD (Metal Organic Chemical Vapor Deposition) reaction chamber to carry out hydrogen atmosphere thermal cleaning; setting process parameters such as target growth temperature, gas flow and reaction chamber pressure; setting the amplitude and period of periodic oscillation around the target growth temperature; iII-group and V-group source gases are synchronously introduced, and a temperature oscillation program is started, so that the temperature of the substrate is periodically oscillated according to set parameters, and epitaxial growth is carried out; continuously oscillating and growing to a target thickness; and stopping the III-group source, and cooling under the protection of the V-group source. The growth interface is actively disturbed through temperature oscillation, so that the growth tends to a two-dimensional layered mode, and the macroscopic thickness and component uniformity of the epitaxial layer are improved. Periodic temperature change is equivalent to in-situ annealing, dislocation density is reduced, and crystal quality is improved. And the method has universality on epitaxial growth of various III-V group compounds such as GaAs, AlGaAs, InGaAs and the like.