9results about How to "Improve on-grid performance" patented technology

The invention relates to the technical field of intelligent power grids, in particular to a grid-connected control method for an improved RBF (Radial Basis Function) network construction type converter with active support capability. The method comprises the following steps: firstly, taking a group of initial values in a VSG system virtual inertia and equivalent damping coefficient parameter value range; determining an initial angular frequency according to the initial value and a swing equation; a VSG secondary control system is improved, an improved phase self-tracking pre-synchronization method without a phase-locked loop is added, a voltage deviation signal is responded, a frequency phase is compensated, and the rotational inertia and the damping coefficient of the system are adjusted in real time to respond to the change of the system state. According to the neural network, the virtual inertia, the damping coefficient and the angular velocity compensation amount are adaptively adjusted, and whether parameters accord with criteria is compared, so that the input parameters are corrected, the influence of disturbance on the system frequency and the output active power is reduced, the dynamic response process of the system is improved, and the stability of the system is improved. And system output power distribution errors and overshoot caused by a rotor motion equation are reduced.

According to the novel electric power system full-band instability factor detection method and the stability control device, the value range of the equivalent impedance of a grid-following type converter and the value range of the included angle between the equivalent impedance of the grid-following type converter and the equivalent impedance of a grid-connected bus when the novel electric power system is unstable are determined to serve as the first condition of instability factor detection; determining a value range of a system power angle and a system impedance angle when the novel power system is unstable, wherein the value range is a second condition for instability factor detection; when the relevant parameters in the novel power system meet any one condition, judging that the novel power system is in full-band instability, and taking the relevant parameters meeting the condition as full-band instability factors of the novel power system; a control signal output by the network construction type converter control module and a control signal output by the network following type converter control module are input into the instability detection control switching module; the coexistence of the following network type and the construction network type in the novel power system is realized, and the stability of power transmission is ensured.

The invention discloses an offshore wind power flexible direct current system cooperative control method and device, particularly relates to the technical field of offshore wind power, and comprises an offshore wind power flexible direct current system cooperative control method which comprises a master-slave control cooperative method. A voltage margin control cooperation method; a droop control cooperation method; the hierarchical control cooperation method further comprises an offshore wind power flexible direct current system cooperation control device which comprises a master-slave control module, a master control station control unit and a slave control station control unit, and a communication unit is used for information interaction between the master converter station and the slave converter station. The method deals with the conditions of offshore wind power plant power fluctuation, alternating current power grid disturbance and the like, avoids large voltage fluctuation and power oscillation, guarantees that the system can still operate basically under the fault condition, meanwhile, achieves optimal distribution of power, provides reliable technical support for large-scale development and utilization of offshore wind power, assists in improving the grid-connected capacity and energy utilization efficiency, and has a wide application prospect. The power generation cost is reduced, and sustainable development of the offshore wind power industry is promoted.

The embodiment of the present application proposes an oscillation suppression method for a grid-type PMSG wind power system connected to a weak power grid. By establishing a Phillips-Heffron-like model of the active-frequency link of the grid-type PMSG wind power system, the influence of key parameters in the system closed-loop transfer function on the subsynchronous oscillation mode is analyzed. In combination with a quantum particle swarm algorithm, an additional damping controller is used to suppress subsynchronous oscillations by maximizing the total damping coefficient of the system. The present invention includes obtaining basic system parameters and weak power grid data, establishing a model and analyzing it, collecting real-time data and identifying anomalies, optimizing control parameters using fault data and a quantum particle swarm algorithm, and monitoring and optimizing the execution effect of the additional damping controller. The present invention effectively improves the stability and grid-connected capability of the grid-type PMSG wind power system in a weak power grid environment.

The invention relates to the technical field of charging and discharging control, in particular to a photovoltaic energy storage integrated system which is composed of a photovoltaic power generation module, a photovoltaic energy storage module, a photovoltaic energy storage distribution module, a photovoltaic adjusting module, a photovoltaic energy storage control module and an intelligent control module. According to the photovoltaic energy storage integrated system, AC-DC conversion and adjustment processing of the variable current control module on the power distribution network module and energy storage and discharge control of the energy storage control module are controlled, so that energy storage of the energy storage control module and complementary power supply control of the power distribution network module on the charging pile module are completed; and meanwhile, the state of the energy storage control module is judged in cooperation with the electric energy judgment module, so that the intelligent control module controls the power distribution control module to receive electric energy emitted by photovoltaic in the charging pile system when the energy storage control module is not full, and controls the photovoltaic adjustment module to supply power to the charging pile system when the energy storage control module is full. The utilization rate of photovoltaic electric energy is improved, the electric energy transmission loss is reduced, and meanwhile the photovoltaic power supply requirement is met.

The invention provides a dynamic voltage control method and system for an energy storage converter, and relates to the technical field of data processing, and the method comprises the steps: carrying out the mathematical modeling of a circuit of the energy storage converter, and building the representation of a voltage in a two-phase rotating coordinate system; according to the expression of the voltage in the two-phase rotating coordinate system, a voltage signal output by the energy storage converter is filtered through a filter, and a filtered voltage signal is obtained; and modulating the filtered voltage signal, and generating a modulation waveform by calculating and distributing the duty ratio of each phase switch so as to control the output voltage of the energy storage converter. Through mathematical modeling, filtering processing, modulation control and an optimization algorithm for simulating the bacterial foraging process, accurate and real-time control of the output voltage is realized, and the response speed and the stability of the system are improved.

This invention provides a method and system for balancing the midpoint potential of a three-level, three-phase, four-wire modular inverter. The method includes: designating one of multiple inverter modules connected in parallel with AC / DC buses as a midpoint potential adjustment module, and the rest as non-midpoint potential adjustment modules; the midpoint potential adjustment module acquires the positive and negative DC bus voltages and calculates the voltage difference between them, performs filtering and closed-loop control calculations on this voltage difference to generate a midpoint potential compensation control quantity, and injects this control quantity as a zero-sequence compensation component into a modulation signal to generate a drive signal to adjust the DC bus midpoint potential; the non-midpoint potential adjustment modules do not participate in the midpoint potential compensation control, but only perform zero-sequence current control. This invention achieves midpoint potential balancing in a three-phase, four-wire inverter without the need for an external hardware balancing circuit, solves the midpoint potential adjustment conflict problem in multi-module AC / DC parallel scenarios, effectively suppresses zero-sequence circulating current, and improves system operational stability.

The application provides a kind of permanent magnet direct drive wind turbine multi-objective control method under power grid asymmetrical fault, solve the technical problem of power fluctuation suppression and current unbalance degree reduction control target coordination optimization in fault ride-through. Including the following steps: S1: establish the positive and negative sequence coordinate system model of permanent magnet direct drive wind turbine grid-side converter, separate the positive and negative sequence of grid-side converter voltage and current;S2: calculate the grid-side converter reference current instruction of three control targets;S3: construct the unified expression form of grid-side converter reference current;S4: select active power fluctuation suppression and negative sequence current suppression as the coordinated optimization control target for control;S5: construct multi-objective optimization function, obtain the converter current reference value, and carry out current closed-loop control on grid-side converter. The beneficial effects of the application are: the multi-objective coordinated optimization control of permanent magnet direct drive wind turbine under power grid voltage fault is realized, and the low voltage ride-through capability and grid-connected performance are enhanced.

The invention relates to the technical field of new energy power generation, and discloses a new energy active support control system and method, and the system mainly comprises a new energy power generation system, an inverter module, a current and voltage collection module, a power calculation module, a transient state quantity adjustment module, a virtual rotational inertia module, a virtual excitation adjustment module, and a control signal module. Transient stable support is provided for a new energy power generation system by simulating rotational inertia and excitation adjustment of a synchronous generator, and output power is adjusted in real time through closed-loop control, so that stable operation of a power grid is ensured. According to the method, active support of a new energy power generation system and stable control of a power grid are realized through the steps of real-time data acquisition and processing, power adjustment and closed-loop control, transient support and fault response, control signal generation, inverter adjustment, continuous monitoring, steady-state operation and the like.