| 摘要 |
A method of controlling the grid-side current of a single-phase grid-connected converter having an LCL filter connected between the output of the converter and the grid, the method comprising the steps of measuring a grid voltage (½ S ) and at least one signal in a group of signals comprising a grid-side current ( i 0 ), a converter-side current ( i 1 ) and a capacitor voltage ( ½ C 0 ). The method comprises the steps of estimating the fundamental component ( ½ S ,1 ) of the grid voltage ( ½ S ), forming a grid-side current reference a converter-side current reference and a capacitor voltage reference for the grid-side current of the LCL filter using the fundamental component of the grid voltage (½ S,1 ), forming estimates for the non-measured signals in said group of signals, forming a grid-side current difference term ( i 0 ), a converter-side current difference term ( i 1 ) and a capacitor voltage difference term ( ½ C 0 ) from the differences between the references and measured/estimated values of said signals, forming an injection term for damping the resonance of the LCL filter by using an active damping injection mechanism (ADI), in which the grid-side current difference term ( i 0 ), the converter-side current difference term ( i 1 ) and the capacitor voltage difference term (½ C 0 ) are used, forming an estimate of harmonic distortion term (Æ ) using the grid-side current difference term ( i 0 ), controlling the output voltage ( e ) of the converter on the basis of the grid voltage, formed injection term and formed estimate of the harmonic distortion term (Æ ) to produce a grid side ( i 0 ) current corresponding to the current reference.
|
