It is important to grasp low voltage ride-through(LVRT)characteristic of inverter for investigating the impact of photovoltaic(PV)station on power grid. Firstly

the topology and control strategy of PV inverter are analyzed. Then the inverter is divided into DC voltage convert part

AC current command part and AC current response part. The key part that dominates LVRT characteristic is investigated. Secondly

a general parameter test method of AC current command part is given. The parameters of reactive current command and active current command are identified successively. Then these parameters are used in simulation model to validate the accuracy. Finally

the analysis conclusion about dominated part is verified by test. A string inverter and a centralized inverter are tested

respectively

and the experimental results show that the test method is well-adapted and effective.