A new unified power quality adjustment device with integrated photovoltaics and its control method

Abstract

The invention provides a novel integrated photovoltaic unified power quality adjustment device and a control method thereof. The device comprises a series transformer, a series converter, a parallel converter, a direct current bus capacitor, a boost converter and a photovoltaic array. When the power grid voltage is reduced, a complex power control method is enabled. The series converter can provide active and reactive power for a load. When the power grid voltage is normal and the power grid voltage increases, the series converter works in a rectification state. The parallel converter works inan inversion state. The direct current bus capacitor is in a charging state. When the power grid voltage drops, the series converter works in the rectification state and the inversion state with thedeepening of the voltage drop degree of a power grid. The direct current bus capacitor is in a charging state and a discharging state with the deepening of the drop degree. The parallel converter works in the inversion state and the rectification state with the deepening of the voltage drop degree of the power grid. When the power grid voltage is interrupted, the photovoltaic array is connected with a direct current bus through the boost converter to provide power for the load.

Description

technical field [0001] The invention relates to the field of power quality management, in particular to a novel unified power quality adjustment device with integrated photovoltaics and a control method thereof. Background technique [0002] Today's power systems require more and more renewable energy installations, especially in low-voltage power distribution systems. This is what has led to an increase in the penetration of renewable energy systems. Although these power electronic loads have high energy efficiency, they inject harmonic currents into the grid, causing distortion at the point of common coupling (Point of Common Coupling, PCC). In addition, some power electronic loads are sensitive to voltage disturbances. In weak distribution systems, due to the intermittent nature of clean energy sources (such as wind and solar energy), PCC voltage fluctuations affect sensitive power loads, such as adjustable speed drives, lighting systems etc., which may lead to frequent...

AI Technical Summary

Problems solved by technology

[0005] Aiming at the problems existing in the prior art to improve the low utilization rate of traditional UPQC series converters and the inability to supply power for a long time when the voltage is interrupted, the present invention provides a new unified power quality adjustment device with integrated photovoltaics and its control method

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