The invention relates to a method for using a one-phase photovoltaic grid-connected
inverter to detect a network
voltage phase. The method for using the one-phase photovoltaic grid-connected
inverter to detect the network
voltage phase is characterized by comprising the following steps of (1) carrying out filtering
processing on collected network
voltage signals, removing higher
harmonic except direct-current components and fundamental frequencies through
filtration, and obtaining a
signal Valpha; (2) carrying out 90-degree phase shifting on the obtained
signal Valpha, and generating a
signal Vbeta, namely, generating a set of orthogonal signals; (3) carrying out d-q conversion on the obtained orthogonal signal Valpha and the obtained orthogonal signal Vbeta according to an
estimation angle theta' of a
power grid, and obtaining a Vd and a Vq, wherein the initial value of the
estimation angle theta' of the
power grid is set to be zero, the operation value can be updated through the step (4) and the step (5), and thus the
estimation angle theta' can reach the real network voltage phase after the
transient state process ends. The method for using the one-phase photovoltaic grid-connected
inverter to detect the network voltage phase has the advantages that interference of the
harmonic in the collected network voltage signals can be removed through
filtration, signals, with the direct-current components, in the collected network voltage signals can be removed through
filtration, and higher
phase locking accuracy can be achieved.