Grid-connected inverter

Abstract

The invention discloses a grid-connected inverter. The grid-connected inverter comprises a DC-DC circuit and a DC-AC inverter bridge which are connected mutually, and further comprises a split-phase controller. The split-phase controller controls the DC-AC inverter bridge to produce an offset current, and the offset current is used for compensating an unbalanced current produced by a load AC port of the DC-AC inverter bridge to enable a current output by the DC-AC inverter bridge to be the same with a current at the load position and to enable different ports of the DC-AC inverter bridge to output different currents, wherein the unbalanced current is produced due to the fact that the load AC port of the DC-AC inverter bridge is connected with different loads. The grid-connected inverter can solve the problem that three-phase power supply is unbalanced, and can automatically compensate reactive power needed by a three-phase load. The more functional inverters are applied, the more obvious the effect becomes. The problems of unbalanced electric power supply and reactive compensation can be solved while the new energy is utilized, the frequency of using an expensive active power filter and a reactive compensation device is reduced, the power supply cost is saved for electric power departments, and the grid electricity supply quality is improved.

Description

technical field [0001] The invention discloses an inverter, more precisely, an inverter used for photovoltaic power generation and grid-connected solar energy. Background technique [0002] In the existing photovoltaic power generation system, the direct current generated by solar panels must be converted into stable alternating current through the grid-connected inverter to realize the grid-connected function, and at the same time realize the maximum power tracking and various abnormal protection functions. The traditional three-phase grid-connected The output power of each phase of the inverter is symmetrical. [0003] The general inverter topology is as follows figure 1 As shown: It is mainly composed of two parts: DC-DC and DC-AC. The main function of the DC-DC part is to track the MPPT and raise the BUS to meet the minimum voltage requirement for grid connection. When the MPPT voltage is greater than the minimum voltage of the UBUS, the DC-DC stops working. [0004] T...

AI Technical Summary

Problems solved by technology

[0007] The purpose of the present invention is to provide a grid-connected inverter, which can solve the problem that the traditional grid-connected inverter in the prior art cannot realize the three-phase load imbalance compensation function due to the symmetrical output of the three-phase power, so if The inverter output can automatically detect the three-phase unbalance and realize the disadvantage of three-phase unbalance compensation

Images