Load current calculating method and apparatus, and bidirectional inverter

The embodiments of the invention relate to the electric power AC field, and disclose a load current calculating method and apparatus, and a bidirectional inverter. The load current calculating methodis applied to the bidirectional inverter. The bidirectional inverter is connected with a power grid and a load. The bidirectional inverter includes a first current transformer and a second current transformer. The load current calculating method includes the steps: detecting an inversion current instantaneous value through the first current transformer, and detecting a power grid current instantaneous value through the second current transformer; according to the inversion current instantaneous value and the power grid current instantaneous value, calculating a load current instantaneous value; and according to the load current instantaneous value, calculating a load current effective value. Through the above mode, the load current calculating method solves the technical problem that in the prior art, detection of