Power conversion system

A power conversion system comprises one or more power conversion devices electrically coupled to a power grid connector. Each power conversion device comprises a power converter, a network-side filter and a load-side filter, wherein the power converter is used for converting a first multi-phase current provided by the power grid connector to a second current, the network-side filter is coupled between the power grid connector and an input of the power converter, the load-side filter is coupled to an output of the power converter, a public point of the network-side filter and a public point of the load-side filter are connected to form a first node, and the first node is not directly connected with the ground.