Grid-connected seamless switching controller based on capacitive current inner ring and control method thereof

Abstract

The invention discloses a grid-connected seamless switching controller based on a capacitive current inner ring and a control method thereof. The controller comprises a microcontroller, a voltage sampling circuit, a grid-connected switch driving circuit and an inverter power tube driving circuit, wherein the microcontroller comprises an electricity grid synchronous module, an output voltage controller, a capacitive reference current generator under a grid-connected mode, a grid inlet current controller, a capacitive current controller, a control command selecting switch and an inverter power tube logic generator. The grid-connected seamless switching controller is connected with an inverter of an electricity grid through a grid-connected switch, is in an output voltage control mode when in dependent operation with load and is in a grid inlet current control mode when in grid-connected operation. The grid-connected seamless switching controller is adaptable to a grid-connected inverter capable of independently operating with grid-connected double modes, increases output voltage load adjustment rate under an independent mode, increases power factors and grid inlet current waveform quality on the condition of non-linear load and electricity grid voltage distortion under a grid-connected mode, and then realizes seamless switching of two work modes.

Description

technical field [0001] The invention relates to a control method of a grid-connected inverter capable of independent and grid-connected dual-mode operation, in particular to a grid-connected seamless switching controller and a control method thereof based on a capacitive current inner loop. Background technique [0002] With the continuous shortage of fossil energy and the increasing environmental pollution, the distributed generation system based on renewable energy has become a research hotspot, and the grid-connected inverter is an important part of it. In order to provide uninterrupted power supply for critical loads, grid-connected inverters with critical loads are required to work in both grid-connected and independent modes. In grid-connected mode, the excess energy is supplied to the grid while supplying power to key loads; in independent mode, power is supplied to key loads. However, when the key load is a nonlinear load, the traditional grid-connected control meth...

AI Technical Summary

Problems solved by technology

The traditional seamless switching control method does not consider the influence of the voltage difference at the moment of switching between the voltage control mode voltage regulator and the current control mode current regulator on the load voltage and grid current

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