The invention relates to a multi-target optimization control method based on a virtual synchronous generator during power grid voltage imbalance. According to the method, a balance current VSG method is firstly utilized to acquire a reference current instruction value in a dq coordinate system; a current instruction value in the grid connected inverter dq coordinate system is acquired through the reference current instruction value in combination with an imbalance power grid voltage parameter when three targets including current three-phase balance, and active or reactive power no fluctuation are realized; a correction value of the three targets is acquired according to relationships between the current instruction value and the reference current instruction value; an optimization coefficient is introduced, and unification of an output current instruction correction value parameter of each target is carried out to acquire an output current instruction correction value of multi-target optimization; the current instruction value is corrected according to the correction value; the current after correction in the dp coordinate system is tracked, through adjusting the optimization coefficient, output current three-phase balance is realized, multi-target control on constant output active or reactive power is realized, and optimum grid connected inverter output performance is realized.

Multi-target optimization control method based on virtual synchronous generator during power grid voltage imbalance

The invention relates to a power grid fault simulation test system movement detection device for a high-altitude photovoltaic power station. The movement detection device is of a vehicle-mounted container structure, is concentrated in three containers by adopting highly integrated design, the three containers are respectively a switch cabinet, a 35 kV electric reactor vehicle and a 10 kV electric reactor vehicle, each container is of a standard size, the transportation limitation requirements are met, and in addition, a centralized control vehicle carries a control system for totally controlling the whole device. The device can perform low voltage ride-through detection capability detection on the photovoltaic power station, can assist users in performing a wind power low voltage ride-through test, can finish switching of a wind power control system and a photovoltaic control system which are different, and is wide in coverage and high in adaptability.

Power grid fault simulation test system movement detection device for high-altitude photovoltaic power station

The invention discloses a three-phase and four-arm inverter control method and system based on a virtual synchronizer. The three-phase and four-arm inverter control method comprises the following steps: firstly, rapidly decomposing asymmetric vectors of three phases into components of symmetrical positive sequence, negative sequence and zero sequence through a sequencing method based on an order-reducing resonator so as to avoid influences of harmonic components on a control circuit; calculating according to voltage and current components of the separated positive sequence, negative sequence and zero sequence, so as to obtain positive sequence reference voltage, negative sequence reference voltage and zero sequence reference voltage; and adding the positive sequence reference voltage, the negative sequence reference voltage and the zero sequence reference voltage together and inputting a three-dimensional space vector based on an abc coordinate system and demodulating, so as to generate a pulse signal for controlling a three-phase and four-bridge arm inversion. According to the three-phase and four-arm inverter control method, independent control of the positive sequence, the negative sequence and the zero sequence can be realized; meanwhile, the influences caused by the negative sequence component, the zero sequence component and the harmonic components of output voltage of the inverter are inhibited and eliminated; the three-phase and four-arm inverter control method has a very good control property under unbalanced and non-linear load conditions; and properties of a synchronous generator are simulated and an accepting capability of a power grid on a distributed power supply is improved.

Three-phase and four-arm inverter control method and system based on virtual synchronizer

The present invention relates to a parameter measurement method of a photovoltaic virtual synchronous generator. The method comprises the following steps that: the parameter measurement structure of the photovoltaic virtual synchronous generator is established, wherein the parameter measurement structure of the photovoltaic virtual synchronous generator comprises a photovoltaic array/photovoltaicarray simulator, a photovoltaic virtual synchronous generator, a data acquisition device, a first damping load, a switch K1 and a second damping load, wherein the photovoltaic virtual synchronous generator operates in an off-grid mode; and the parameters of the devices in the parameter measurement structure are adjusted, so that the damping coefficient and rotational inertia of the photovoltaic virtual synchronous generator are determined. With the parameter measurement method provided by the invention, the damping coefficients and rotational inertias of various photovoltaic virtual synchronous generators can be determined, and a sound foundation is provided for the formulation of the related standards of photovoltaic virtual synchronous generators.

Parameter measurement method of photovoltaic virtual synchronous generator

The invention relates to an alternating-current/direct-current-system reactive power optimization method based on a good-point set quantum particle swarm algorithm The method comprises the following steps of step1, establishing an alternating-current/direct-current-system reactive power optimization model; step2, improving a quantum genetic algorithm; and step3, using the improved quantum genetic algorithm to solve the alternating-current/direct-current-system reactive power optimization model In the invention, the QPSO is improved and a problem of premature convergence generated because the QPSO is easy to fall into local optimum is solved

Alternating-current/direct-current-system reactive power optimization method based on good-point set quantum particle swarm algorithm

The invention discloses a method and a device for controlling three-phase unbalanced current of a virtual synchronous generator. The method comprises the following steps: establishing a rotor movement equation of the virtual synchronous generator (VSG) and a virtual excitation equation of the VSG; decomposing unbalanced voltage of a power grid into positive sequence voltage, negative sequence voltage, zero sequence voltage and corresponding phase-sequence current, and decomposing active power and reactive power output by the VSG to analyze an encountered imbalance problem; calculating a reference instruction of dq axis current according to the output three-phase voltage signal; and converting the reference instruction of the current into a pulse-width modulation (PWM) voltage modulation signal through a self-designed current inner ring, and controlling the virtual synchronous generator to run through the PWM voltage modulation signal, so as to enable the output three-phase current of the virtual synchronous generator to reach the balance. According to the control method disclosed by the embodiment of the invention, the VSG can still output three-phase balanced current when the three-phase voltage of the power grid is unbalanced, so that the operation safety of the power grid can be relatively well ensured; and the method and the device are safe, reliable, simple and convenient.

Method and device for controlling three-phase unbalanced current of virtual synchronous generator

The invention relates to a large photovoltaic power station reactive optimization method based on improved immune particle swarm optimization algorithm, and belongs to the technical field of photovoltaic power station control. The method comprises the following steps: 1) establishing a photovoltaic power station stable state operation model to analyzing the voltage, wherein the model comprises an instation current collection line, a step up transformer and power transmission line impedance; 2) establishing a multi-target reactive power optimization model, and performing fuzzy processing of multiple targets; and 3) solving by using the improved immune particle swarm optimization algorithm. The large photovoltaic power station reactive optimization method based on improved immune particle swarm optimization algorithm can significantly improve the grid-connection point voltage and the instation voltage distribution, and can significantly reduce the instation active loss when the power station outputs greatly.

Large photovoltaic power station reactive optimization method based on improved immune particle swarm optimization algorithm

The utility model relates to mobile detection equipment for a grid fault simulation test system for a high-altitude photovoltaic power station, and the equipment employs a vehicle-mounted container structure. A switch cabinet car, a 35 kV electric reactor car and a 10 kV electric reactor car are disposed in three containers in a mode of high-integration. The size of each container is standard, thereby meeting the requirements of transportation limitation. In addition, a centralized control vehicle carries a control system for the overall control of the whole equipment. The equipment can detect the capability of low-voltage ride-through detection of the photovoltaic power station, and can assist the testing of low-voltage ride through of wind power, can achieve the switching of wind power and photovoltaic systems, is wide in coverage, and is high in adaptability.

Mobile detection equipment for grid fault simulation test system for high-altitude photovoltaic power station

The invention relates to an active power optimal dispatching method for suppressing photovoltaic power fluctuation. The method comprises: reading distributed photovoltaic generated power of an hth dispatching period, outputting an ultra short time predicted value PPV(h) and an ultra short time load prediction value PL(h), calculating an active power dispatching instruction PES(h) of an energy storage power station; according to real-time acquired operating state uk (h) and carrying capacity SOCk(h) of each battery pack of the energy storage power station, defining three kinds of dispatching states of the battery packs; determining the active power dispatching instruction of the energy storage power station, according to power distribution priority principle that priority dispatching can optimize charging and discharging battery packs and post-dispatching cannot optimize the charging and discharging battery packs, and according to priority proportional distribution, and using a power distribution strategy of rated power distribution, calculating power values distributed to each battery pack in a current dispatching period; and summarizing the active power dispatching instruction of each battery pack, and sending to the energy storage power station. The method reduces overcharging and over-discharging of battery packs, and prolongs life of the battery packs.

Active power optimal dispatching method for suppressing photovoltaic power fluctuation

The invention discloses an unbiased estimation photovoltaic inverter parameter identification method based on the dual-density wavelet network. The method comprises the steps of S1, acquiring voltage and current input and output by a photovoltaic inverter; S2, processing voltage and current by means of the dual-density wavelet network; S3, correcting voltage and current by means of the unbiased autoregression algorithm; S4, acquiring a photovoltaic inverter parameter estimation model according to corrected voltage and current values. According to the method, a photovoltaic inverter model is divided into a linear part and a non-linear part by means of the dual-density wavelet network, so that the precision and real value of a parameter identification model are improved; the unbiased autoregression algorithm is adopted to eliminate the influence of colored noise on system parameter identification; a self-adaption method is adopted to reduce the influence of data contingency on the model, and the adaptability of the parameter identification model to different working conditions is improved.

Yang Libin

Papers

Method and device for controlling three-phase unbalanced current of virtual synchronous generator

Large photovoltaic power station reactive optimization method based on improved immune particle swarm optimization algorithm

Mobile detection equipment for grid fault simulation test system for high-altitude photovoltaic power station

Active power optimal dispatching method for suppressing photovoltaic power fluctuation

Unbiased estimation photovoltaic inverter parameter identification method based on dual-density wavelet network