Output differential feedback based adaptive control method of virtual synchronizer

Abstract

The invention discloses an output differential feedback based adaptive control method of a virtual synchronizer. The method comprises the steps that 1) an output current, an output voltage and a power-grid voltage of a three-phase full-bridge inverter are collected and converted into digital quantities respectively; 2) excitation of the virtual synchronizer is output via reactive voltage regulation control, and an output voltage amplitude and a power-grid voltage amplitude are calculated; 3) active power, reactive power and excitation electromotive force of the system are calculated; 4) speedfeedback control is realized, and an initial value of a speed feedback coefficient is calculated; 5) active frequency modulation control is realized, virtual synchronizing angular velocity and phase are output, and a rotating speed difference and an angular acceleration of the virtual synchronizer are calculated; 6) adaptive regulation rules of the virtual inertia moment and speed feedback coefficient are set; 7) CLARK transformation is carried out to obtain a voltage quantity in an alpha-beta static coordinate system; and 8) spatial vector modulation is carried out to obtain six paths of control switch pulses of the three-phase full-bridge inverter, and thus, three-phase AC feedback power grid is realized.

Description

technical field [0001] The invention belongs to the technical field of grid-connected control of renewable new energy power generation, and relates to an adaptive control method of a virtual synchronous machine based on output differential feedback. Background technique [0002] With the shortage of fossil energy and the limitation of carbon dioxide emissions, the proportion of renewable new energy power generation to the total power generation continues to increase. Renewable new energy power generation is generally connected to the grid through power electronic converters, without the rotor and large rotation of traditional generators. Inertia is not conducive to grid stability. To solve this problem, virtual synchronous generator technology makes new energy generation nodes have similar external characteristics to traditional synchronous generators by simulating the external characteristics of synchronous generators, which improves the stability of power grid systems cont...

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Problems solved by technology

[0005] The purpose of the present invention is to provide a virtual synchronous machine adaptive control method based on output differential feedback, which solves the problem that under the existing technical conditions, the system active frequency modulation characteristics and system damping characteristics cannot be taken into account so that the system can effectively work in an overdamped state, thereby Problems that lead to power overshoot damage to power electronic equipment and frequent charging and discharging of energy storage equipment; system transient optimization problems and grid frequency exceeding the set threshold during transient adjustment, resulting in system off-grid operation that threatens grid stability question

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