Three-phase grid-connected inverter double-loop control method based on proportional complex integral control

Abstract

The invention relates to a three-phase grid-connected inverter double-loop control method based on proportional complex integral control. The inner loop adopts filter capacitor current feedback control, the outer loop control adopts PCI control, infinite gain can be achieved at the fundamental wave, an alternating current designated signal is effectively tracked, the control precision of network entry current is improved, tracking without steady-state error is basically achieved, and the network entry current power factor is increased; by adopting double-loop control, the system damping is increased, a resonance peak of the system is effectively restrained, the system stability is improved, compared with traditional PI control and quasi-resonance control, under the same parameter condition, the system has the higher stability margin, and the reliability is greatly enhanced. The waveform quality, the tracking precision and the power factor of grid-connected current are improved, meanwhile, a bridge arm switching tube can be protected, and it is ensured that the inverter system is safely and reliably operated. The method is applicable to solar power generation, wind power and other new energy grid-connected systems, and can be popularized to a control method of other single-phase or three-phase grid-connected inverters.

Description

technical field [0001] The invention relates to an inverter control technology, in particular to a dual-loop control method for a three-phase grid-connected inverter based on proportional complex integral control. Background technique [0002] With the development of economy and energy consumption in modern society, the pollution caused by traditional fossil energy and its own depletion are inevitable. Human beings pay more attention to renewable energy. Wind energy and solar energy are clean and non-polluting new energy sources with rich content and are the first choice. The inverter technology is one of the extremely important technologies in the process of connecting new energy to the grid. [0003] The inverter output current must pass through a filter to filter out high-order harmonics. The commonly used filters today are L-type filters, LC-type filters and LCL-type filters. The L-type filter has a simple structure and is easy to implement, but the filtering effect is...

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Problems solved by technology

This method is simple and effective, but the added resistance will undoubtedly increase system consumption and affect efficiency

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