61results about How to "Suppresses frequency fluctuations" patented technology

A SAW device has an IDT which is provided on the principal surface of a quartz crystal substrate having Euler angles (−1.5°≦φ≦1.5°, 117°≦θ≦142°, 42.79≦|ψ|≦49.57°) and excites a SAW in a stopband upper end mode, and a pair of reflectors which are arranged on both sides of the IDT. Inter-electrode-finger grooves are recessed between the electrode fingers of the IDT, and inter-conductor-strip grooves are recessed between the conductor strips of the reflectors. A first direction (X′ axis) perpendicular to the electrode fingers and the conductor strips intersects the electrical axis (X axis) of the quartz crystal substrate at an angle ψ. At least a part of the IDT and the reflectors are arranged in a second direction intersecting the first direction at an angle α of 1.0°≦α≦2.75°. An excellent frequency-temperature characteristic and a high Q value in an operation temperature range are realized simultaneously.

A SAW device includes an IDT which is provided on the principal surface of a quartz crystal substrate having Euler angles (−1.5°≦φ≦1.5°, 117°≦θ≦142°, |ψ|≠90°×n (where n=0, 1, 2, 3)) and excites a Rayleigh wave (wavelength: λ) in a stopband upper end mode. Inter-electrode-finger grooves are recessed between electrode fingers of the IDT. An IDT line occupancy η and an inter-electrode-finger groove depth G satisfy a predetermined relationship in terms of the wavelength λ, such that the SAW device has a frequency-temperature characteristic of a cubic curve having an inflection point between a maximum value and a minimum value in an operation temperature range. The inflection point is adjustable to a desired temperature or a desired temperature range depending on the IDT line occupancy η within an operation temperature range.

The invention discloses a frequency control method and system for an interconnected power system containing energy storage resources. The control method comprises the following steps: establishing a frequency response model of a regional interconnected power system containing energy storage frequency modulation resources; performing frequency division processing on the ACE signal to obtain a powerreference value borne by a traditional unit and an energy storage resource; establishing a space state model and discretizing the space state model; designing a distributed model prediction controller, and establishing an optimization objective function and constraint conditions; and solving a quadratic programming problem formed by the optimal objective function and the constraint condition to determine an optimal control sequence, and enabling a first control variable in the control sequence to act on a traditional unit and energy storage resources to realize optimal control. The control strategy provided by the invention can reasonably allocate the frequency modulation responsibilities of a traditional unit and the energy storage resources, gives play to the advantages of quick outputof energy storage and large frequency modulation capacity of the unit, and can quickly stabilize the frequency fluctuation caused by load and new energy injection in a power system.

The invention provides a control method and a control system for wind power participating frequency modulation of an electric power system. The control method comprises regulating and controlling the frequency of the electric power system by using rotor kinetic energy and a storage battery energy storage system. According to the control method for wind power participating frequency modulation of the electric power system based on combined effect of the rotor kinetic energy and the storage battery energy storage system, the wind energy is sufficiently utilized, the configuration capacity of the energy storage system is reduced, and the economical efficiency of wind field operation is improved. The control method and the control system can also play better roles even under the condition of relatively great load disturbance.

The invention discloses a method for quickly and effectively inhibiting frequency fluctuation of an island power grid. The conventional methods cannot effectively inhibit the influence of impact load and wind power field output change on the frequency of the island power grid. The invention adopts the technical scheme that: a frequency correction module is arranged in a constant active power controller on the inverter side of voltage source converter high-voltage direct current (VSC-HVDC), the power set value of the constant active power controller can track the change of system frequency through the frequency correction module, and the power fed into the island power grid is changed by using the quick response property of a voltage source converter (VSC) so that the island power grid still keeps active power balance under the action of impact load and during abrupt change of the wind power field output and the frequency of the system is kept stable.

The invention discloses a method for allowing a permanent magnetic direct drive wind power generation system to participate in frequency adjustment of a power grid on the basis of fuzzy control. A permanent magnetic direct drive wind power unit can change frequency adjustment power output by the permanent magnetic direct drive wind power unit according to real-time frequency of the power grid through coordination control over a motor side convertor, a power grid side convertor and a flywheel energy storage unit side convertor. The method has the advantages that maximum wind power tracking control can be achieved while auxiliary frequency adjustment power is provided for the power grid; control parameters of the power grid can be flexibly changed under all working conditions according to power grid frequency conditions, equivalent inertia and damping of the system can be dynamically adjusted, and the permanent magnetic direct drive wind power unit can participate in frequency adjustment of the power grid to the maximum degree.

The present invention provides a vehicle lamp capable of suppressing frequency fluctuation of a switching converter. A boost converter (410) having an ADJ terminal boosts a power supply voltage to generate a direct current voltage (VDC) stabilized at a variable target voltage corresponding to voltage of the ADJ terminal (VADJ), a buck converter (430) receives the direct current voltage (VDC) to supply a driving current (ILAMP) to the light source (310). A hysteresis controller having a hysteresis control mode is configured to stabilize the driving current (ILAMP) between a peak value and a bottom value around the target current and to change a difference between the peak value and the bottom value such a switching frequency of the buck converter (430) approaches a constant value, and a voltage adjusting circuit (460) is configured to dynamically change the voltage of the ADJ terminal (VADJ) of the boost converter (410) according to an output voltage (VOUT) of the buck converter (430).

A sound emitter (1) according to an embodiment comprises an oscillator (10), and an exciter (piezoelectric oscillation element (20)). The exciter (20) is disposed upon the oscillator (10), receives an input of an electrical signal, and oscillates. The exciter (20) further comprises either protrusion parts (29) or depression parts (39) on the oscillator (10) side surface thereof.

A piezoelectric vibrating piece includes a pair of vibration arm portions that is placed in a row in a width direction; a base portion to which proximal end sides in the pair of vibration arm portions in an extending direction are connected; and weight metal films that are formed on outer surfaces of the vibration arm portions, wherein the weight metal films are formed in positions that avoid regions of tip portions in the vibration arm portions in a longitudinal direction.

The invention relates to an optical module for atomic oscillator and atomic oscillator. The optical module for an atomic oscillator uses a quantum interference effect. The optical module includes a light source adapted to emit light including a fundamental wave having a center wavelength, and sideband waves of the fundamental wave, a wavelength selection section receiving the light from the light source, and adapted to transmit the sideband waves out of the light input, a gas cell encapsulating an alkali metal gas, and irradiated with light transmitted through the wavelength selection section, and a light detection section adapted to detect an intensity of light transmitted through the gas cell. The wavelength selection section includes an etalon and a temperature control section adapted to control temperature of the etalon.

The invention relates to an optical module for an atomic oscillator and an atomic oscillator. The optical module for an atomic oscillator using a quantum interference effect includes a light source adapted to emit light including a fundamental wave having a predetermined wavelength, and sideband waves of the fundamental wave, a wavelength selection section receiving the light from the light source, and adapted to transmit the sideband waves out of the light input, a gas cell encapsulating an alkali metal gas, and irradiated with light transmitted through the wavelength selection section, and a light detection section adapted to detect an intensity of light transmitted through the gas cell, and the wavelength selection section includes a fiber Bragg grating, and a voltage application section adapted to apply a voltage to the fiber Bragg grating.

The invention discloses a quasi-PCI and PI combined control single-phase photovoltaic grid-connected inverter current control method in the technical field of new energy photovoltaic power generation.The method comprises the following steps of: adding a cut-off frequency into a proportional complex integral (PCI) controller to form a quasi-PCI controller; realizing a complex number field in a single-phase quasi PCI through a lag output item of a second-order generalized interactor (SOGI); taking a difference value between a given grid-connected current iref and an actual grid-connected current iL as the input of the quasi-PCI controller; taking a difference value between a grid-connected current direct current quantity reference value IL-dc and a grid-connected current direct current quantity as an input of a PI controller; and after the output of the quasi PCI controller and the output of the PI controller are added, controlling the switching-on and switching-off of an inverter switching tube through PWM modulation. According to the invention, the influence of power grid voltage fluctuation and frequency offset on the grid-connected current is suppressed, the direct-current component of the grid-connected current is eliminated, and high-quality control is realized while the design of a non-isolated photovoltaic grid-connected inverter current controller is simplified.

To provide a thermoelectric module that can be arranged in a limited space and is excellent in heat exchange capability, and to provide an optical transmitter comprising the same. A first insulating substrate (21) comprises the following components: a substrate body (21a) with a first opposite surface (21c); and a protruding part (21b) which is integrally formed with the substrate body (21a) on an opposite surface that is at the opposite side of the first opposite surface (21c) and is opposite with an area provided with an electrode. The protruding part (21b) is provided with a thermoelectricconversion element (24) and a connection part (42) connected with a cooled object. The heat generated by the cooled object is efficiently transferred from the protruding part (21b) to a second insulating substrate (22) with the thermoelectric conversion element (24).