Photovoltaic inverter parameter identification method

Can LVRT test identify the parameters of a PV inverter?

In the case that the PV inverter control strategy and parameters are not disclosed, a method is proposed to realise the identification of the three types of parameters through the LVRT test. The method can solve the difficulty in performing the tests of Groups 2 and 3 parameters in the field.

What are the reference values for a PV inverter?

The reference values of the active and reactive currents can be expressed as follows: PDC−VDC curves with r = 0 Ω and r = 0.042 Ω, respectively. In the failure mode, the PV inverter operates at point G1 (actual operating point) when r = 0.042 Ω, and the DC voltage rises by 111 V.

How can LVRT test be used to identify a PV system?

To simplify the test items and steps needed for parameter identification, an appropriate identification and modelling method for a PV generation system is proposed on the basis of an LVRT test. This LVRT field test is conducted on a large PV system in North China. The three groups of parameters are identified with the test data.

How does a PV inverter work in failure mode?

In the failure mode, the PV inverter operates at point G1 (actual operating point) when r = 0.042 Ω, and the DC voltage rises by 111 V. The PV inverter operates at G2 when r = 0 Ω, and the DC voltage rises by 98 V. A noticeable difference of 11.7% exists between the two operating points.

How is the PV characteristic curve modified based on field test data?

Considering the equivalent resistance of the collection line, the PV characteristic curve was modified based on field test data. In particular, a method for calculating PV array model parameters was proposed.

How are Pi parameters identified?

Identification method for parameters of Group γ: The PI parameters of the DC voltage loop are identified based on the DC-side voltage data obtained from the measurement. (vii) The acquired parameters are substituted into the simulation model for model verification and result evaluation.