The invention relates to a
low voltage ride-through control method of a permanent magnetic direct drive
wind power system under unbalanced network
voltage. The control method includes the concrete steps that first, the phase theta and the phase theta<n> of positive and negative sequence voltages are acquired; second, through the positive and negative sequence
voltage phases, voltages and currents of a three-phase network are converted in a dq coordinate
system, and positive and negative sequence voltages and currents in the dq coordinate
system are obtained; third, through the positive and negative sequence network currents and parameters of a
network connection reactor, the active
power consumption direct current component deltaP<0>, the cosine component deltaP<c2> and the sine component deltaP<s2> on the
network connection reactor are calculated; fourth, the reference value of the
direct current component of active
power output by an
inverter and the reference value of the
direct current component of reactive
power output by the
inverter are acquired; fifth, through the obtained reference values of power, the positive and negative sequence components of the output current of the
inverter are calculated; sixth, switching signals are obtained through the positive and negative sequence components of the output current, and the output current and the output power of the inverter are controlled through the switching signals. Compared with the prior art, the
low voltage ride-through control method of the permanent magnetic direct drive
wind power system under unbalanced network
voltage has the advantages of being efficient, easy and convenient to operate and the like.