149results about How to "Suppress low frequency oscillation" patented technology

The invention belongs to the field of power systems, and in particular to a method which uses an additional damping controller to modulate active and reactive output of a doubly-fed wind generator to increase low-frequency oscillation damping of a grid connection power system of a large-scale wind farm. According to the invention, the method uses auto-disturbance rejection control technology, introduces the theory of data driving control, engineers an additional damping controller of the wind generator, and makes feature signal of the connecting points of a wind farm as input of the additional damping controller which outputs a signal to be added to active and reactive modulation quantity of a machine side current converter. According to the invention, simulation of the method proves that negative damping low frequency oscillation and forced power oscillation are better controlled, and the method has stronger robustness and engineering practicality. The invention provides a novel method for adjusting parameters of a state observer of a second-order non-linear auto-disturbance controller based on broadband concept.

The utility model discloses an excitation control method based on nonlinear robust power system stabilizer, which belongs to the technical field of power system stability control. The utility model is characterized in that a nonlinear robust power system stabilizer is put forth on the basis of multi-machine excitation system nonlinear mathematical model and by combining differential geometry control theory and nonlinear HíÌ method. The output signals of the nonlinear robust power system stabilizer are superimposed with the output signals of an original automatic voltage regulator to generate excited control signals, which are used to control the excitation system of the generating set, thus preventing the influence of external uncertainties, solving the problems of dynamic nonlinearity and high coupling in power system, overcoming the defects of neglecting the nonlinearity inherent in the system in prior art, improving the dynamic stability and expanding the installed capacity of the generating set to the maximum extent.

The invention discloses a multichannel direct current added damping control device capable of simultaneously restraining sub-synchronization and low frequency oscillation, and a parameter setting method of the multichannel direct current added damping control device. The device is characterized in that the device identifies the subsynchronous oscillation, the low frequency oscilation frequency and the damping of a direct current under island running and a system reduced-order model on the basis of a matrix pencil algorithm which has high operation efficiency and anti-interference capacity, a multichannel direct current added damping controller is designed through a root locus method so as to reduce mutual effects between oscillation modes, and sub-synchronization and low frequency oscillation can be simultaneously restrained. Electric generator rotating speed signals are divided into multiple frequency bands according to results of analysis conducted on characteristics of system oscillation through the matrix pencil algorithm, a passageway corresponding to each frequency band can independently adjust the gain, the phase position, the output amplitude limit and the filter parameters, and therefore appropriate damping can be provided for sub-synchronization and low frequency oscillation in different frequency bands. The device is efficient and easy to obtain, and the function of simultaneously restraining sub-synchronization and low frequency oscillation through the direct current added damping controller is achieved for the first time in the high voltage direct current transmission field.

The invention discloses a method for implementing a power system stabilizer. The method includes steps of acquiring a rotation speed variable quantity via a blocking filter link according to the rotation speed and active power of a rotor of a power generator, and respectively acquiring low-band differential signals, medium-band differential signals and high-band differential signals via a differential filter; parallelly adding the low-band differential signals, the medium-band differential signals and the high-band differential signals together to acquire rotation speed variation comprehensive signals of the power generator; measuring phase-shift characteristics of the rotation speed variation comprehensive signals and the rotation speed and uncompensated phase-shift characteristics of an excitation control system of the power generator by a forced oscillation process, computing required phase-shift characteristics among the rotation speed variation comprehensive signals and the power system stabilizer, designing multi-order lead-lag link phase-shift parameters which are serially multiplied by one another, performing phase compensation to meet the required phase-shift characteristics; finally outputting signals of the power system stabilizer and superposing the signals of the power system stabilizer on a reference voltage of an excitation regulator of the power generator. The method has the advantage that active power low-frequency oscillation of the synchronous generator can be effectively suppressed.

The invention discloses a VIENNA rectifier neutral point potential alternating-direct-current component balance control method which can reduce design capacity of a capacitor on a direct-current side and a filter on an alternating-current side and save cost of a tri-level VIENNA rectifier. On the basis of common mode component injection modulation, a common mode component direct-current compensation coefficient and an alternating-current compensation coefficient are modified dynamically, so that the problem of neutral point unbalance of direct-current and alternating-current components is solved; more importantly, the method guarantees uniformity between triphase alternating-current side harmonic distortion rate and SVPWM while substantially inhibiting neutral point potential low-frequency oscillation in conventional modulation methods and improving quality of output power and can be popularized and applied in the field of battery testing, charging facilities and driving systems.

The invention discloses a double-feed blower fan synchronous motor system and a method for inhibiting the oscillation of a synchronous generator. The method comprises the steps: detecting a power network voltage through a locked-phase loop, obtaining d-axis and q-axis component signals of the power network voltage, carrying out the processing of the d-axis and q-axis component signals through two different error amplifiers and a phase compensator unit, and obtaining two compensation signals; enabling the two compensation signals to respectively serve as the front feed for the current control of a rotor side converter of a wind power generator, and adding the two compensation signals to the instruction values of the d-axis and q-axis components of a rotor current, so as to respectively compensate for the d-axis and q-axis components of the rotor current. The method achieves the control of amplitude and phase of the internal potential of a double-feed blower fan through the compensation control of the rotor current, further affects the amplitude and phase of the internal potential of a synchronous motor through a power transmission line, and achieves the inhibition of the oscillation of the synchronous generator. Because the corresponding speed of a current loop is high and the d-axis and q-axis components of an electronic current can quickly track the instruction values, an oscillation signal can be extracted quickly when the synchronous generator generates oscillation, and the method quickly provides positive damping for the rotor of the synchronous motor through adding a stable signal.

The invention relates to a self-adaptive damping control method of a virtual synchronous generator. The self-adaptive damping control method comprises the steps of: acquiring relevant parameters of avirtual synchronous generator system; judging whether low-frequency oscillation occurs in the virtual synchronous generator system according to the relevant parameters, if not, returning to the previous step to acquire data continuously, and if so, adjusting a virtual damping value in the virtual synchronous generator system in a self-adaptive manner according to the acquired relevant parameters;and realizing frequency adjustment of the virtual synchronous generator system according to the virtual damping value. Compared with the prior art, the self-adaptive damping control method has the advantage of being capable of effectively suppressing the low-frequency oscillation of the system.

A low-frequency band suppression enhanced anti-reversal power system stabilizer is presented by the invention. Currently the widely used PSS2B power system stabilizer needs lead elements above Order 2 to meet the phase compensation requirement of DC blocking signal of active power, thus quickly increasing high-frequency band gain, restricting allowable total setting gain of PSS, limiting low-band gain and reducing low-frequency band suppression ability of power system stabilizer. The invention will add generator speed signal ω (which is treated by DC blocking element and corrected by parallel proportional differential PD) and active power signal P_e (which is treated by DC blocking element and gained by gain factor K_s3) to get equivalent synthetic mechanical power of power system stabilizer. The actual active power signal gained by gain factor K_S1 can meet the requirement of phase compensation through Order 1 lead and lag elements, thus increasing allowable total setting gain of PSS and improving the ability of low-frequency band oscillation suppression.

The invention relates to a generator wide area damping control method based on a model-free adaptive control algorithm and belongs to the electric power system stabilization analysis technology field. The method comprises steps that control parameters of a traditional generating wide area damping control method are acquired according to a traditional transfer function expression and a parameter calculating formula; control parameter initial values of the generator wide area damping adaptive control method is calculated according to the acquired control parameters of the traditional generating wide area damping control method, an acquired pseudo gradient vector initial value is taken as an initial point, and an estimated value of a pseudo gradient vector is updated online by utilizing input output data actually measured by a controlled system; a generator wide area damping adaptive control signal is calculated according to the estimated value of the pseudo gradient vector which is updated online; repeated calculation is carried out till the generator wide area damping control signals reach to a maximum level. The method can guarantee a control effect of generator wide area damping control under multiple operation states of the system.

The invention relates to a wide-area damping control method based on identification of a power system model. The wide-area damping control method based on identification of the power system model includes the following steps that an observing signal is collected by means of a wide-area measuring system; pre-processing is carried out on the obtained observing signal to obtain a stable time sequence and the Bayes criterion is used for carrying out order determination on an ARMA model; an identification result is obtained by means of an improved ARMA model recognition algorithm; the time-lag power system state space model is obtained and a linear matrix inequality gamma and a linear matrix inequality theta are set up for obtaining the maximum time lag upper limit h which can be tolerated by the system and a controller K; fifthly, an output signal of the controller K is attached to a generator set excitation side which is in strong correlation with a low-frequency oscillation mode to finish damping control. According to the wide-area damping control method based on identification of the power system model, the computational process is simple, the operation speed is high, the obtained maximum time lag upper limit can meet the practical requirements and engineering realization is easy to achieve.

The invention belongs to the field of power systems, in particular relates to a method for distinguishing negative damping low frequency oscillation caused by a power generator excitation control system on the basis of moment decomposition integral algorithm. The method comprises the steps of: calculating a power generator transient state potential bias deltaE'q and determining a power generator speed bias delta omega, wherein the power generator speed bias delta omega is obtained through calculation according to a frequency of a potential EQ in a power generator, and whether damp provided by an excitation system of the unit is positive or negative relative to some oscillation mode in an Internet power grid is judged through calculating an integral value of the power generator transient state potential bias deltaE'q and the power generator speed bias delta omega. The method is convenient for measurement and is accurate, and can simply and clearly distinguish which oscillation mode of some power generator excitation control system provides a positive damp or negative damp so that measures are rapidly taken for inhibiting low frequency oscillation.

The invention discloses an emergency control method for a small signal stability state of a new energy power system, and relates to the technical field of new energy power system control methods. The method comprises the following steps of determining a key mode damping ratio to be a random output variable; fitting the key mode damping ratio and a random input vector by adopting a random response surface method and carrying out Hermite polynomial chaos expansion; monitoring the power system by using a Hermite polynomial chaos expansion-based formula and building a rescheduling optimization problem about random input variables once the unstable state of the power system is detected; and solving the rescheduling optimization problem, obtaining emergency control measures according to the solving result and implementing the emergency control measures. According to the method disclosed by the invention, the small signal stability state of the new energy power system can be monitored in real time; and an emergency control scheme is quickly given during small signal instability.

The invention provides a damping control method and system for an electric power system provided with a plurality of wind turbines. The damping control method comprises the following steps: measuring wind turbine connecting line power signals and inter-regional communication connecting line power signals to obtain wind turbine connecting line power fluctuation signal sequences and inter-regional communication connecting line power fluctuation signal sequences; constructing an electric power system state space model according to the signal sequences in conjunction with a sub-space state space identification algorithm for the electric power system, wherein the model comprises a system matrix; calculating a dominant oscillation mode of the system matrix, and acquiring controllability of the wind turbine connecting line power fluctuation signal sequences to the dominant oscillation mode; selecting wind turbines to be equipped with additional damping controllers according to the controllability; and designing additional damping controller models through a phase compensation method, inputting the inter-regional communication connecting line power fluctuation signal sequences into the additional damping controllers, and outputting a wind turbine rotation speed adjusting signal to increase damping. Through the technical scheme of the invention, the effect of restraining low-frequency oscillation of the electric power system can be enhanced.

A method for using the rotational kinetic energy of a permanent magnet synchronous draught fan for improving electric system damping comprises the following steps: step A, a parameter estimation method of a total least squares-rotation invariant subspace algorithm is used for identifying an inter-area oscillation mode frequency omega d according to a power fluctuation signal delta Pac of a tie line; step B, under a perturbation, the phase angle difference phi 2 between a fan rotor speed omega and wind power Pd is measured, the phase angle difference between the wind power Pd and an inter-area inertia center angular frequency omega COI is phi 1, and a phase angle phi 3 which needs compensation is calculated, wherein the phi 3 is equal to the sum of the phi 1 and the phi 2; then, a phase compensation method is used for setting a first time constant Ta and a second time constant Tb in a phase compensation link and a gain factor K in a gain link in a supplementary damping controller for the permanent magnet synchronous draught fan; step C, an inversion signal -Pac of the tie line is input into the supplementary damping controller so as to output a signal to adjust the rotating speed of the draught fan, wherein the signal is a draught fan rotating speed adjustment signal omega damp; therefore, the rotational kinetic energy of the draught fan is used for improving the electric system damping.

The invention discloses a high-speed-rail low frequency oscillation overvoltage damping method based on multi-variable control. The method comprises establishment of a bullet train networking side rectifier state space model, a design of a multivariable feedback control matrix, designs of a state observer and a state observation matrix, a design of a setting value calculating module and a design of feedforward control. The establishment of the state space model is a premise of realizing a control method. The state observer is used for estimating a voltage and a magnitude of current of a direct current link resonance portion, wherein the voltage and the magnitude of current are used for control calculating. A measurement apparatus does not need to be increased additionally. In the invention, a difference between an estimation value of a state amount and a setting value is organized and integrated via the multivariable feedback matrix; the multivariable feedback matrix is calculated and acquired through a linear quadratic optimal control algorithm and a contradiction between control input consumption and a control performance demand can be reasonably balanced. The feedforward control is used to further accelerate a dynamic response characteristic of the control. In addition, by using the control method, a problem of traction network-bullet train group electric quantity low frequency oscillation can be effectively restrained.

The invention relates to a control method of an ultra-high direct-current transmission voltage, which is characterized by comprising the following steps: (1) in a pole control system on the inversion side, calculating the voltage drop between a direct-current line and an earthing pole line according to the direct current and direct-current voltage of the local pole, the direct current of the opposite pole and the direct-current voltage of the opposite station, and setting the reference value of the direct-current voltage as the voltage level of the single valve bank on the rectifying side; (2) and subtracting half of the voltage drop between the direct-current line and the earthing pole line from the reference value of the direct-current voltage to obtain the control device voltage reference value of each valve bank, controlling the direct-current voltage on the two ends of the local valve bank to the obtained voltage reference value, and determining the operating voltage level on the rectifying side by using the direct-current voltages of the two valve banks. The invention solves the technical problems in rectifying-side fixed current control and inversion-side fixed voltage control in the ultra-high direct-current transmission engineering.

The invention provides an alternating-current and direct-current parallel decentralized control method based on a pi-type topological structure. The method comprises the steps of determining a transfer function of a system in the dynamic process and a transfer function of the system in the static process, identifying the transfer functions according to TLS-ESPRIT to obtain a system vibration mode, determining a feedback signal of a controller and a preliminary matching scheme of installation sites according to the system vibration mode, calculating an ERGA of a control loop according to the transfer functions and the preliminary matching scheme and determining a feedback signal of the controller and an optimal matching scheme of the installation sites according to the ERGA and the preliminary matching scheme. According to the alternating-current and direct-current parallel decentralized control method based on the pi-type topological structure, the system vibration mode is analyzed through TLS-ESPRIT, the feedback signal of the controller and the preliminary matching scheme of the installation sites are determined, and the optimal matching scheme is determined through ERGA indexes. According to the ERGA, interaction of the dynamic condition and the static condition is considered, uncertainty of the system is reduced, control reliability is improved, robustness of a control device is improved, the cost is reduced, low frequency oscillation of large power grid areas in an alternating-current and direct-current parallel power transmission system is inhibited, and the method is suitable for various types of controllers.

The invention discloses a united low-frequency oscillation online monitoring method of wide area measurement systems of multiple dispatching centers, comprising the following steps of: selecting one from the wide area measurement systems of the multiple dispatching centers as a united oscillation monitoring main station, and taking the wide area measurement systems of other dispatching centers as sub-stations; when any sub-station or main station monitors low-frequency oscillation, triggering total network united low-frequency oscillation analysis; performing spectrum analysis on respective measurement points by each sub-station, and gathering analysis results to the main station to perform modal analysis such as coherency clustering of oscillation nodes of the total network and calculation of the relative contribution degree of each node to oscillation; returning the global results of analysis to each sub-station and performing visual display in the form of renderings. By the method, the wide area measurement system of each dispatching center can timely know detailed oscillation modal information of a low-frequency oscillation event influencing own grid, such as oscillation range, node clustering situation, interface position, degree of participation of own grid unit in oscillation, and the like.

The invention discloses a method for suppressing vehicle network low-frequency oscillation and a system thereof. The method comprises the steps that a network side voltage instantaneous value, a network side current instantaneous value, DC side output voltage, DC side output current, a DC side output voltage given value, a network side filtering inductance value and a network side equivalent resistance value are acquired; a first initial modulation signal is obtained according to the network side voltage instantaneous value, the DC side output voltage, the DC side output voltage given value, the network side filtering inductance value and the network side equivalent resistance value; a second initial modulation signal is obtained according to the network side current instantaneous value, the resistance value of a preset virtual resistor and the network side voltage phase obtained according to the network side voltage instantaneous value; and difference processing is performed on the first initial modulation signal and the second initial modulation signal so that a difference value is obtained, and the difference value acts as an output PWM signal to the modulation signal of the PWM generator of a network side rectifier. The low-frequency oscillation of the vehicle network system can be effectively suppressed so that the stability of the vehicle network system can be enhanced without increasing hardware cost.

The invention relates to the technical field of integrated circuit design and manufacture, in particular to a single chip power amplifier which is widely used for various kinds of active radar components of W wave band millimeter waves and communication systems. An input match circuit is integrated on a single chip, the input end of the input match circuit is connected with an external signal input source, the output end of the input match source is sequentially connected with a four-level transistor amplifier, an output match circuit and a power synthesis circuit in series and then outputs outside, wherein the four-level transistor amplifier comprises a first level transistor amplifier, a second level transistor amplifier, a third level transistor amplifier, and a fourth level transistor amplifier. The single chip power amplifier can be widely used for the fields of various kinds of active radar components of W wave band and millimeter wave communication systems. The single chip power amplifier has the advantages of being wide in working frequency range, stable in full frequency range property, and capable of effectively decreasing an area of a chip and loss, and achieving high power output of the chip.

The invention discloses an electric power system stabilizer and a method, relates to the technical field of electric power, and mainly aims to overcome the shortcoming of relatively poor low-frequency oscillation suppression effect of the existing electric power system stabilizer. The electric power system stabilizer comprises a voltage regulator, an active compensation frequency regulator, an automatic exciting regulator, a stabilizer, a control additional apparatus and a generator network, wherein the stabilizer comprises a sensor, a high-frequency filter, a compensator and an amplifier; the automatic exciting regulator comprises an exciting power unit and an exciting regulator; and the voltage regulator comprises a voltage measurement comparison unit, a pulse width modulator, a low-frequency protection unit and a voltage-stabilizing circuit.

The invention discloses a double input PSS experiment method which comprises a first channel input signal and a second channel input signal. The first channel input signal is a signal of mechanical angular velocity and the second channel input signal is an electrical power input signal. The method comprises the following steps: 1. shielding the second channel and verifying an effect of the first channel input signal on inhibiting electrical-network low-frequency oscillation through modifying ramp function passband; 2. shielding the first channel and verifying an effect of the second channel input signal on inhibiting electrical-network low-frequency oscillation through modifying the ramp function passband. In the invention, the double input PSS can be effectively verified whether the double input PSS can have effect on inhibiting low-frequency oscillation in a full frequency range with the effect of the PSS through shielding one of the channels. Stability of the electrical network canbe raised.

The invention provides an SVG-based frequency closed-loop control method for dynamic suppression of low-frequency oscillation in a power grid. The control method comprises the steps of: collecting three-phase voltage of the power grid; tracking the three-phase voltage of the power grid to obtain a power grid frequency; filtering the power grid frequency to obtain an actual frequency value for suppression of low-frequency oscillation of the power grid; getting the difference between the actual frequency value for suppression of low-frequency oscillation of the power grid and a reference frequency value for suppression of low-frequency oscillation of the power grid so as to form a power grid frequency deviation value, and performing proportional integral control of the power grid frequency deviation value to obtain a control amount corresponding to the power grid frequency deviation value; conducting closed-loop control of the control amount corresponding to the power grid frequency deviation value to obtain a compensation voltage for suppression of low-frequency oscillation of the power grid, and suppressing low-frequency oscillation of the power grid. The control method of the invention can dynamically and effectively suppress low-frequency oscillation of the power grid.

The invention relates to an adaptive wide-area damping controller. The adaptive wide-area damping controller comprises an adaptive delay compensator and an N input and output GrHDP unit; the adaptivedelay compensator is used for obtaining N first wide-area measurement signals, performing adaptive delay compensation and outputting N second wide-area measurement signals; the N input and output GrHDP unit is used for receiving the N second wide-area measurement signals and obtaining N first coordinated control signals based on an adaptive dynamic programming algorithm; and the adaptive delay compensator is also used for receiving the N first coordinated control signals and obtaining N second coordinated control signals by calculation based on a GrHDP model algorithm. According to the adaptive wide-area damping controller disclosed by the invention, multiple input and multiple output are carried out by adoption of the GrHDP unit; multi-target coordinated adaptive control on multiple low-frequency oscillation modes of a power system can be simultaneously carried out; the adaptive capability of the power system is improved; furthermore, both the first wide-area measurement signals and the first coordinated control signals are subjected to delay compensation; the control influence of delay onto the power system is greatly avoided; and the damping improvement of the controller onto the power system is improved.