81results about How to "Reduce frequency fluctuation" patented technology

A high-frequency heating device including: a solid-state oscillator that generates a microwave; an amplifier that amplifies the microwave generated by the solid-state oscillator; an isolator that is connected to a stage subsequent to the amplifier and blocks a reflected wave directed from an object exposed with the microwave; an antenna that irradiates the microwave toward the object; and a metal cavity that traps therein the microwave irradiated to the object.

The invention discloses an optimal control system and method for primary frequency modulation of thermal power generating units based on water supply compensation. The system comprises a first subtraction device, a piecewise function module, a first adding device, a second subtraction device, a hysteresis module, a proportion module, a high or low limit amplitude module, an analogue quantity selector, a second adding device, a controller, an absolute value module, a first comparator, an operation module and a second comparator. According to the frequency deviation of a power grid, the main steam pressure is changed by using the change of water supply flow, so that the movement range of the primary frequency modulation of the generating units is effectively improved, the rapidity and accuracy of dispatching a primary frequency modulation response by the thermal power generating units are improved, and then the capability of frequency modulation is ensured, and the frequency fluctuationsof a power system are reduced.

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 relates to the air conditioner control technology, and provides a control method of a permanent magnet synchronous brushless direct-current motor in low frequency. The control method of the permanent magnet synchronous brushless direct-current motor in low frequency is used for solving the problems that when a compressor works, axis error estimation is inaccurate, and position detection of the compressor is out of step. The control method of the permanent magnet synchronous brushless direct-current motor in low frequency comprises the steps that (1) a system collects phase current of the permanent magnet synchronous brushless direct-current motor through a current detection unit, transmits the phase current to a coordinate transformation unit to obtain a d-axis current component Id and a q-axis current component Iq of the phase current, and transmits the d-axis current component Id and the q-axis current component Iq to an axis error estimation unit; (2) the system calculates an error delta theta between the actual position of a motor rotor and an estimated position of the motor rotor according to the obtained parameters such as the d-axis current component Id and the q-axis current component Iq; (3) after the system compares a current working frequency f of the permanent magnet synchronous brushless direct-current motor with a first frequency f1 and a second frequency f2, the system calculates a speed presumption unit input value delta theta PLL, and calculates the current estimated rotating speed omega c of the rotor, and a current estimated position theta c of the motor rotor is determined through a phase presumption unit. According to the control method of the permanent magnet synchronous brushless direct-current motor in low frequency, the axis error delta theta is reduced artificially, namely, amplitude limiting processing is carried out on the axis error, the effect of restraining control is achieved, and the control method of the permanent magnet synchronous brushless direct-current motor in low frequency is applicable to the permanent magnet synchronous brushless direct-current motor.

The invention relates to a wind power considered thermal power frequency modulation unit configuration method, in particular to a regional power grid thermal power frequency modulation unit configuration method considering wind power uncertainty fluctuation, in order to solve the problem of influence caused on system frequency stabilization after large-scale wind power integration. The method includes: performing decomposition and restructuring of a wind power time sequence by taking a Mallat wavelet decomposition and restructuring algorithm as a tool, establishing an instantaneous model of second-scale and minute-scale wind power plant power uncertainty fluctuation on the basis of a wavelet multi-scale analysis method, giving a time-domain instantaneous expression prior to establishing a wind power regional power grid model used for frequency modulation analysis, giving an expression for representing primary and secondary frequency modulation capacities of the system based on the frequency modulation analysis, and quantitatively analyzing and computing the primary and secondary frequency modulation capacities of the system under different conditions on the basis of the frequency modulation capacity expression. By the method, system frequency fluctuation caused by wind power fluctuation can be reduced, and system frequency stability is maintained. The method is applicable to wind power considered thermal power frequency modulation unit configuration.

The invention discloses a primary frequency modulation dynamic compensation adjustment system and method based on performance index evaluation. The system comprises a primary frequency modulation dynamic compensation adjustment calculation module, a frequency modulation dynamic compensation determination module, a frequency modulation dynamic compensation output module, a frequency modulation power constant-value compensation module, a comprehensive valve position increment compensation module and a comprehensive valve position command generation module. By performing dynamic compensation adjustment on a frequency modulation power setting and a comprehensive valve position increment, a moderate overshoot is used to ensure the rapid return of a grid frequency and ensure that a unit primaryfrequency performance index meets a standard requirement. The method calculates a dynamic compensation coefficient according to the amplitude of the primary frequency modulation operation at a relevant time point of the unit and the operation integral power amount in a corresponding time period, and adjusts the variation quantity of the primary frequency modulation of the unit in a targeted manner, thereby improving the accuracy of the thermal power generation unit to schedule the primary frequency modulation response, satisfying the demand of the grid for the unit primary frequency modulationoperation, ensuring its frequency modulation capability and reducing the frequency fluctuation of a grid system.

The invention provides a control method and system for a photovoltaic power station participating in system frequency modulation, wherein the method comprises the following steps: calculating an active power regulation amount of a photovoltaic power station according to grid-connected point frequency and a frequency change rate of a photovoltaic power station; correcting the initial command valueof active power of photovoltaic power station according to the active power regulation quantity of photovoltaic power station to obtain the final reference value of active power of photovoltaic powerstation; and based on the final active power reference value of the photovoltaic power station, controlling the active power of the grid-connected point of the photovoltaic power station. The technical scheme provided by the invention judges the disturbance magnitude of the power network through the frequency change rate, and adopts the emergency control to immediately increase or decrease different fixed active powers to regulate the active powers of the photovoltaic power station, thereby strengthening the support strength of the power network frequency, reducing the frequency fluctuation amplitude of the power network and increasing the stability of the power network.

A semiconductor circuit device includes an oscillation circuit, an output circuit that receives a signal output from an oscillation circuit and outputs an oscillation signal, a temperature sensing element, a characteristic adjustment circuit that adjusts characteristics of the oscillation circuit on the basis of a signal output from the temperature sensing element, and a first connection terminal that is electrically connected to the output circuit and via which the oscillation signal is output, in which a distance between the output circuit and the first connection terminal is shorter than a distance between the temperature sensing element and the first connection terminal in a plan view.

The invention discloses a method for a permanent magnet direct drive wind power generation system to participate in power grid frequency regulation. A generator side converter, a power grid side converter and an energy storage unit side converter are controlled. An energy storage unit converter controls voltage and combines a rotor position angle and direct current link voltage to acquire a PWM drive signal of the energy storage unit side converter through space vector modulation SVM to control a motor. When the motor accelerates to the highest rotation speed, a power / current closed-loop control mode is switched into a rotation speed / current closed-loop control mode, and the rotation speed is given as the rated rotation speed of a flywheel motor. When the flywheel motor continuously slows down to zero, the rotation speed outer ring given value is set to zero, and the rotation speed of the motor is controlled as zero. Through rotation speed / current closed-loop control, the flywheel motor runs at zero speed. According to the method, a wind turbine can acquire a stable frequency regulation ability in all conditions, and the grid connection adaptability of the wind power system is improved.

The invention relates to a control system for a grid frequency of a large-scale charging station. The control system comprises a charging station information sending and receiving module, a charging station control module, a control strategy output module and a charging pile information receiving and sending module, wherein the charging station information sending and receiving module is respectively connected with a grid dispatching center and the charging pile information receiving and sending module. According to the system, through large-scale electric automobile participation frequency fluctuation response and according to the condition that charging and discharging power can be utilized by the charging station in real time, electric automobiles in the charging station are arranged orderly for charging and discharging.

A one-port surface acoustic wave resonator includes a rotated Y-cut LiTaO3 substrate, an interdigital electrode transducer disposed on the LiTaO3 substrate, and reflectors disposed on both sides of the interdigital electrode transducer in the surface acoustic wave propagation direction of the interdigital electrode transducer. When the electrode finger width of the interdigital electrode transducer is denoted by a and the gap between the electrode fingers is denoted by b, the metallization ratio, a / (a+b), is in the range of about 0.55 to about 0.85 and the interdigital electrode transducer is overlapping-length weighted.

The invention discloses a phase switching method for rapidly adjusting a phase of a reference voltage of an inverter. The method comprises the following steps of controlling the inverter to supply power to a neutral section by using a control system so that a train flexibly passes through a neutral section with no power failure; exerting the control system to obtain phase information of an input voltage signal of a corresponding power supply arm through a voltage sensor and a phase-locked loop and exerting the control system to further obtain a phase difference Delta Upsilon; systematically reconstructing a reference voltage signal in the phase amplitude adjusting process by using a phase adjusting coefficient K Theta; and switching the reference voltage after the adjusting process is finished. The phase switching method for rapidly adjusting the phase of the reference voltage of the inverter, disclosed by the invention, is advantaged in that the phase adjusting speed of an output voltage of the inverter can be increased, frequency fluctuations in the phase adjusting process can be reduced and unfavorable effects of the phase adjusting process on the system can be completely eliminated.

A network synchronization method allows reduced frequency fluctuations due to synchronization control in a network. Each node connected to the network has time information individually varying in a period of T. A time master node periodically notifies its own time information to time slave devices. Each time slave node prepares update-possible time points having a period of T / N (N>1). When receiving master time information, each time slave node updates its own time information using the master time information at an update-possible time point just after the master time information has been received.

The invention provides a self-adaptive virtual inertia frequency modulation control method for a flexible direct-current power transmission system. The control method comprises the following steps of:firstly, realizing secondary frequency modulation of an alternating-current side system by controlling a reference value of active power in droop control; secondly, enabling virtual inertia power tobe equal to capacitor charging and discharging power, and establishing a coupling relationship between a direct-current voltage reference value and the active power; adopting self-adaptive virtual inertia control adjusted according to a fitting hyperbolic tangent function, reducing an inertia coefficient when a direct-current voltage is close to a limit value, thereby preventing the direct-currentvoltage from exceeding the limit value; and increasing the inertia coefficient when the direct-current voltage is far away from the limit value, thereby making the frequency more stable. With the method adopted, the overshoot in the secondary frequency modulation process is reduced, the frequency recovery of an instantaneous fault is facilitated, the frequency stability of an AC system is improved, and the stability of an interconnection system is improved.

A timing signal generation device includes a PLL circuit that synchronizes a first clock signal of an atomic oscillator with a reference timing signal of a GPS receiver, a PLL circuit that synchronizes a second clock signal of an oven-controlled crystal oscillator with the first clock signal, a first count reset unit that enables resetting of a count value of a divider in the PLL circuit when an operation of the PLL circuit is restarted, and a second count reset unit that enables resetting of a count value of a divider in the PLL circuit when the operation of the PLL circuit is restarted.

The invention relates to a power system inertia real-time evaluation method based on ARMAX system identification. The method is based on the following steps: (1) obtaining active power and frequency fluctuation of outlet sides of generators and a wind power plant when a power grid operates normally; (2) taking the active power change as input and the frequency change as output, and constructing anARMAX identification model from the active power change to the frequency change; (3) calculating a frequency change rate after step response of the ARMAX identification model; and (4) substituting the frequency change rate after the step response into a swing equation to obtain an inertia time constant. Compared with the prior art, the method provided by the invention has the advantages that dynamic changes of inertia of the power system in different operation states can be accurately reflected; an auxiliary decision is provided for stable operation of a power grid and grid connection of newenergy; an evaluation result can be updated in real time according to measured data; and understanding of potential unstable risks of the power system and stable operation maintaining capability afteraccidents are facilitated.

The present invention discloses a grid-connected unit primary frequency modulation rapid adjustment system and method in direct current faults. The system comprises a monitoring module and a frequencymodulation control module which are connected through a transmission channel, the monitoring module is configured to perform power change monitoring and fault monitoring through operation of the direct current circuit in a regional power grid, generate direct current emergency frequency modulation signals when it is integrally determined that the power change monitoring and fault monitoring bothmeet a certain condition, and calculate quantified emergency frequency deviation value signals according to the momentary fluctuation value condition of the direct current power in the regional powergrid; and the frequency modulation control module is configured to perform dynamic switching of the frequency deviation value of the unit frequency modulation control logic to achieve emergency advanced adjustment of the frequency. The grid-connected unit primary frequency modulation rapid adjustment system and method in direct current faults perform emergency frequency modulation control for thegrid-connected unit in a pointed mode to effectively solve the problem that the response of the grid-connected unit is not synchronous when the switching power is greatly fluctuated caused by faults of the direct current circuit at the advanced unit frequency modulation response time point and ensure the high synchronism of the grid-connected unit and the power grid frequency fluctuation.

A PLL circuit has an averaging device for averaging a rectangular wave signal output from a phase comparator at every period of a reference clock signal, and for outputting the average value. After the establishment of the phase synchronization of the PLL circuit, the average value of the averaging device becomes a stationary reference level. Accordingly, the output clock signal generated by a voltage controlled oscillator can reduce its output frequency fluctuations in accordance with the reference level.

A sampling frequency converter has a buffer that stores data in response to a write request signal, and outputs stored data in order from the oldest data in response to a read request signal. An interpolation unit sequentially receives data from an external source, performs an interpolation operation at a generation timing of a write request signal for calculating interpolated data from a specified number of the most recently received data, and supplies the interpolated data to the buffer. A writing speed adjusting unit recurrently generates a write request signal at a time rate determined according to frequency control information. A speed correction pointer increases a pointer value each time a write request signal is generated, and decreases the pointer value each time a read request signal is generated. A frequency control unit corrects the frequency control information based on the pointer value of the speed correction pointer.

To provide a condensate flow rate control device and a control method for a power plant which improve responsiveness to frequency fluctuations or requested load changes and can suppress frequency fluctuations with precision or improve precision with which output power conforms to requested load instructions. A power plant to which a condensate flow rate control device is adapted includes a deaerator to which condensate generated by a condenser is supplied via a deaerator water level adjustment valve and into which bleed steam from a steam turbine is introduced. The condensate flow rate control device has a water level adjustment unit for executing condensate flow rate control, wherein the water level adjustment unit adjusts pressure in a condensate flow path extending from the deaerator water level adjustment valve to the deaerator so that inputted frequency fluctuations are suppressed or an output value of a generator conforms to inputted requested load changes.

The invention discloses a dynamic allocation method and device for an AGC unit based on a regional power grid active power gap. The method comprises the steps: monitoring whether the regional power grid has a fault or not; calculating an overall active power vacancy value, an overall active power change rate and an emergency active power change rate in a network in real time; and adding or quitting allocation on the AGC unit according to the rate gap if the emergency active power change rate is higher than or lower than an existing overall active power change rate in the network. The AGC unitis deployed according to the real-time active power change rate of a power grid, thereby guaranteeing the average value, zero crossing and other indexes of the power grid area control deviation withinthe specified time. The number of AGC units in the period is controlled when the power grid fluctuation is small, thereby reducing the frequency fluctuation of a power grid system, avoiding invalid actions of the units, and achieving coordinated development of a power grid source.

A semiconductor circuit device includes an oscillation circuit, an output circuit that outputs a signal output from the oscillation circuit, a temperature sensing element, a characteristic adjustment circuit that adjusts characteristics of the oscillation circuit on the basis of a signal output from the temperature sensing element, a first wiring via which power is supplied to the output circuit, and a second wiring via which a reference voltage is supplied to the output circuit in which at least one of the first wiring and the second wiring overlaps the temperature sensing element in a plan view.

The invention discloses a power-grid frequency modulation control system and method with participation of an electric boiler. The control system comprises an electric boiler dynamic module, a generating system equivalence module and an electric boiler frequency response module; according to a backwater temperature and a heating power sampling value of present time, the electric boiler dynamic module calculates the average water body temperature of the electric boiler of next time, and transmits the average water body temperature to the electric boiler frequency response module; the generating system equivalence module obtains the system frequency fluctuating condition according to the load state as well as a rotor motion equation; and according to the system frequency fluctuating condition, the electric boiler frequency response module determines whether to participate in frequency modulation of the system, calculates the frequency modulation potential of the electric boiler according to the received average water body temperature of the electric boiler of next time, and adjusts the heating power of the boiler according to the frequency modulation potential of the boiler and enables the electric boiler to participate in system frequency modulation control. Thus, the control system changes the load of the electric boiler, adjusts the power rapidly, and keeps a balance between the generating power and the load demand.

The invention discloses an island alternating-current microgrid secondary frequency control method based on linear active disturbance rejection. With the purpose of reducing the frequency and realizing the stable operation of a microgrid, an island alternating-current micro-grid model containing wind, light, firewood and storage is established, the influence of demand response is considered, the linear active disturbance rejection technology is applied to load frequency control, a linear active disturbance rejection controller is designed, a linear expansion state observer is adopted to perform online real-time estimation on the expansion state, active compensation is performed on the estimated disturbance, and therefore the effects of rapidly eliminating the disturbance and keeping the frequency stable are achieved. The control method inherits the advantages of simplicity and convenience in debugging and easiness in use of a proportion-integral differential (PID) controller, has better control quality on a nonlinear, uncertain and strong-coupling system, and can achieve a better decoupling effect, so that the robustness and the adaptability of the system under an unknown strong-disturbance effect are enhanced.

The invention discloses a primary frequency modulation assessment index calculation method based on time point comprehensive processing. According to requirements in state-specified standards of GB / T 30370-2013 and Q / GDW 669-2011, based on the real-time power value and the frequency value of a unit acquired by a power grid main station end, the rotation speed change rate L3 of the unit at a 3s time, the rotation speed change rate L15 of the unit at a 15s time and the rotation speed change rate L30 of the unit at a 30s time are calculated respectively, greatest option processing is carried out on the three calculated rotation speed change rates L3, L15 and L30, the greatest value L is comprehensively used as a rotation speed change rate in the primary frequency modulation performance indexes of the unit for assessment, and whether the primary frequency modulation is qualified is judged. Multipoint rotation speed change rate calculation can be carried out, the primary frequency modulation assessment index effectiveness and the accuracy are enhanced, the unit is ensured to meet primary frequency modulation action working quickness and stability requirements by the power grid, and the power grid is ensured to operate safely and stably.

The invention relates to an attenuation circuit for an energy storage device having one or more energy storage modules which are connected in series in one or more energy supply lines and have at least one energy storage cell and a coupling device which has a multiplicity of coupling elements and is designed to selectively switch or bridge the energy storage cell in the respective energy supply line. The attenuation circuit comprises a current detection device which is designed to detect an output current of the energy supply lines or of the energy storage device and to generate an output current signal dependent on the output current, a control circuit which is coupled to the current detection device and is designed to control the output current signal to a desired current signal and to output a corresponding current control signal, and a pulse width modulation device which is coupled to the control circuit and is designed to control the coupling device of at least one of the energy storage modules in a clocked manner on the basis of the current control signal.

The invention discloses a power-type energy storage frequency modulation responsibility dividing method based on secondary planning, and the method comprises the steps: optimizing the output power ofa frequency modulation power supply through the secondary planning according to the basic information of the frequency modulation power supply and the real-time state information of the frequency modulation power supply, and achieving the precise tracking of a regional error signal. Meanwhile, when a tracking failure is caused by objective factors (insufficient frequency modulation power), a linear planning method is employed for achieving the minimization of a tracking error. The method makes the most of the quick reaction capability of an energy storage device, achieves the precise trackingof a secondary frequency modulation signal of a system to the maximum degree, and improves the frequency modulation capability of a power grid. In addition, the method also can enable the charge stateof the battery energy storage to remain nearby a set value, guarantees the remaining charging and discharging capacity, and prolongs the service life. Meanwhile, the method effectively reduces the equipment loss, caused by the frequent climbing, of a conventional motor in a frequency modulation process.

The invention discloses a method and a system for primary frequency modulation parameter self-adjustment control based on assessment data. The method includes the following steps: determining the primary frequency modulation qualification rate index standard value of a unit in a grid primary frequency modulation assessment system according to the running mode of the unit; comparing the primary frequency modulation qualification rate index standard value of the unit with the actual primary frequency modulation qualification rate index of the unit in the assessment system to get the primary frequency modulation qualification rate index deviation of the unit; and dynamically adjusting the primary frequency modulation power variation of the unit according to whether the primary frequency modulation qualification rate index deviation of the unit is beyond an adjustment scope, wherein the parameters of adjustment are set according to the active power variation index in the assessment system. The frequency modulation performance of the unit can be dynamically adjusted. The accuracy of response of the thermal power unit to primary frequency modulation scheduling is improved. The demand of the grid for the work of the unit primary frequency modulation action is satisfied. Safe and stable operation of the unit is considered while the frequency modulation ability is ensured.

A system for reducing temporal fluctuations in a powered magnet. The system includes a magnetic field generator that generates a magnetic field with temporal fluctuations and a power supply having an AC / DC converter that delivers electric current to the magnetic field generator. A cascade compensator having an inner control loop that outputs an inner loop signal and an outer control loop that outputs an outer loop signal is included. The inner control loop has a pickup coil and an analog integrating preamplifier and the outer control loop has a magnetic resonance field estimator. The inner control loop senses fluctuations of the magnetic field over 1 Hz and the outer control loop senses fluctuations of the magnetic field from DC to 20 Hz. The cascade compensator generates a correcting magnetic field that cancels the fluctuations based on the inner loop signal and the outer loop signal.