Current sharing control in a parallel inverter system
AssigneeKabushiki Kaisha Toshiba
InventorKazuto Kawakami
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Abstract
This inverter system is directed to an inverter system in which a plurality of inverters adapted for generating output voltages corresponding to a voltage reference and a frequency reference respectively given through voltage controllers and frequency controllers are operated in parallel. In this inverter system, a difference between an output current of a corresponding inverter and output currents of other inverters is detected. By implementing the d-q axis orthogonal coordinate transform processing to that current difference, a first correction signal relating to the frequency of an output voltage of that inverter and a second correction signal relating to the amplitude of the output voltage thereof are provided.
Claims13
An inverter system including a plurality of inverters connected in parallel,
- each of said plurality of inverters comprising:
- current detection means for detecting an output current of a corresponding inverter;
- voltage control means for generating a voltage control signal corresponding to a difference between a voltage reference and an actual voltage of said corresponding inverter;
- frequency control means adapted for generating a frequency control signal corresponding to a difference between a frequency reference and an actual frequency of said corresponding inverter;
- current difference formation means for forming a current difference signal relating to said corresponding inverter on the basis of a detected result of said current detection means;
- d-q axis orthogonal coordinate transform means for transforming a current difference signal formed by said current difference detection means to a signal on the d-q axis orthogonal coordinate system, thus to form a first correction signal relating to the frequency of an output voltage of said corresponding inverter and a second correction signal relating to the amplitude of said output voltage thereof;
- first correction means for correcting said frequency control signal by said first correction signal;
- second correction means for correcting said voltage control signal by said second correction signal;
- and
- means for controlling said corresponding inverter in accordance with outputs from said first correction means and said second correction means.
Dependencies are inferred from the claim text.