Non-AC voltage sensor control method of grid-connected inverter

Abstract

The invention discloses a non-AC voltage sensor control method of a grid-connected inverter. The non-AC voltage sensor control method of the grid-connected inverter is characterized by comprising the following steps of: collecting three-phase grid-connected current iabc and DC bus voltage udc in real time, observing power grid side AC voltage ealphabeta by an AC voltage observer and calculating reactive power Q; obtaining an active current instruction as shown in the specification and a reactive current instruction as shown in the specification, obtaining three-phase SPWM modulation signal as shown in the specification and modulating the three-phase SPWM modulation signal as shown in the specification; generating a switching signal Sa,b,c of driving the inverter and controlling on or off of a switch tube through the switching signal of driving the inverter, thereby achieving control on the inverter. On or off of the switch tube is controlled through the switching signal of driving the inverter, so that the control on the inverter is achieved; the AC voltage observer is constructed by applying a TOGI-OSG; the hardware cost is reduced; the power grid adaptability of the inverter under the distributed energy access condition is improved; the problems of an integral initial value, integral saturation and DC bias in the observation process are solved, and due to the filtering effect of a TOGI, the sine degree of the grid-connected current is good and the harmonic content is low.

Description

technical field [0001] The invention relates to the technical field of distributed power generation, in particular to a method for controlling a grid-connected inverter without an AC voltage sensor. Background technique [0002] In recent years, renewable energy sources such as wind power and photovoltaics have developed rapidly, and a large number of large-scale wind and photovoltaic power plants have been established in China. With the continuous improvement of the penetration rate of distributed renewable energy, the status of grid-connected inverters in the traditional distribution network has become more and more prominent. In order to efficiently and reliably complete the distributed grid connection of renewable energy and effectively reduce the impact of grid-connected inverters on the grid, it is necessary to solve the impact of the intermittent and randomness of renewable energy on the voltage stability of the access system. In order to realize grid-connected power...

AI Technical Summary

Problems solved by technology

In practice, the low-pass filter is generally used instead of the pure integral, but the low-pass filter will inevitably bring about deviations in amplitude and phase, which will affect the stability of the grid-connected current waveform and the DC bus voltage.

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