Parallel inverter wireless carrier synchronization method, device, medium and computer equipment

Abstract

The invention relates to a method, device, storage medium and computer equipment for wireless carrier synchronization of a parallel inverter. The three-phase voltage of the power grid is sampled according to the sampling period of the parallel inverter, and the power grid under the three-phase static symmetrical coordinate system is The instantaneous value of the three-phase voltage is transformed into a voltage signal in the two-phase vertical stationary coordinate system; according to the preset inverter sine-cosine table, the voltage signal in the two-phase vertical stationary coordinate system is transformed into a voltage signal in the two-phase synchronous rotating coordinate system . When the voltage signal under the two-phase synchronous rotating coordinates is not zero, the sampling error is obtained by performing a proportional integral operation according to the voltage signals under the two-phase synchronous rotating coordinates. The sampling period is updated according to the sampling error and the three-phase voltage of the power grid is sampled again. Through feedback adjustment, the error is gradually reduced to complete the synchronous modulation and phase-locking of each parallel inverter, without adding carrier synchronization signal lines, realizing wireless carrier synchronization of each parallel inverter, and improving the reliability of wireless parallel operation.

Description

technical field [0001] The invention relates to the technical field of power grids, in particular to a method, device, storage medium and computer equipment for carrier synchronization of parallel inverters. Background technique [0002] With the increase of electrical equipment and the improvement of power level requirements, the parallel connection of inverters is more and more widely used. The inverter parallel system makes the system power be reasonably allocated among the inverters according to their rated capacity, so that the circulating current between the inverters is suppressed. If there is a circulating current in the inverter parallel system, it will affect the reliable operation of the system. The circulating current is divided into power frequency circulating current, harmonic circulating current, DC circulating current, etc. These circulating currents are load-shared through the average current control method or virtual impedance control method, but there is ...

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Problems solved by technology

If there is a circulating current in the inverter parallel system, it will affect the reliable operation of the system

The circulating current is divided into power frequency circulating current, harmonic circulating current, DC circulating current, etc. These circulating currents are load-shared through the average current control method or virtual impedance control method, but there is another kind of circulating current in the parallel system called switch circulating current, that is, inverter The difference of the modulated carrier of the inverter module will also cause a certain degree of switching frequency ripple in the output current. This circulating current cannot be suppressed by the average current and virtual impedance, so the consistency of the modulated carrier of the inverter module must be solved

[0003] The carrier synchronization method of the traditional inverter parallel system is to add a carrier synchronization communication line between the parallel units to achieve carrier synchronization, but it increases the hardware cost and the risk of hardware failure, and it is based on the carrier synchronization communication line to achieve carrier synchronization. The effect of synchronization belongs to wired parallel machine, and it cannot realize wireless parallel machine carrier synchronization

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