Three-phase inverter capable of working without parallel connection by interconnection lines and control method thereof

Abstract

The invention relates to a three-phase inverter capable of working without parallel connection by interconnection lines and a control method thereof. The three-phase inverter comprises an inversion power circuit and an inversion control circuit, wherein the inversion control circuit comprises an inversion and parallel connection control DSP unit, an output voltage sampling circuit, a filtering inductive current sampling circuit, a drive control circuit, a connection power busbar voltage sampling circuit, a connection power busbar voltage sampling and conditioning circuit, and a connection power busbar voltage phase acquisition circuit. The inversion and parallel connection control DSP firstly performs synchronization control according to connection power busbar phase signals to keep the coincident frequency and the coincident phase of the inverter and a connection power busbar; and then, the inversion and parallel connection control DSP fine tunes the phase and the amplitude of reference signals respectively according to the output power of the inverter to realize uniform flow control, and performs certain constraint on phase deviation of the inverter and the connection power busbar by using the synchronization control. The three-phase inverter has the advantages of simple circuit structure, easy implementation, and improvement on stability and reliability of systems without parallel connection of the interconnection lines.

Description

technical field [0001] The invention belongs to the technical field of parallel control of sine wave inverters without interconnection wires, and in particular relates to a method and the technical field of realization of parallel operation of three-phase inverters without interconnection wires. Background technique [0002] There are two methods for parallel control of inverters: interconnection with signal and interconnection without signal. The latter is referred to as "parallel connection without interconnection wires". The conventional method of parallel connection without interconnection wires is based on the drooping method of external characteristics. After detecting the output power of the module and calculating the active and reactive power, the frequency and frequency of the output voltage of the module are adjusted respectively. amplitude, etc. to achieve current sharing. Its advantage is that the hardware is simple, no additional lines need to be added external...

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Problems solved by technology

[0004] But the main disadvantage of this scheme is that the decoupling control needs to use the line reactance 2πfL p , resistance r LP The power calculation method is decoupled with the load resistance R, and the power calculation method is relatively complicated, and there is no special control method for the conditions and process of putting into parallel connection

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