Low-voltage crossing method of doubly-fed fan based on superconducting magnetic energy storage and improved control

Abstract

The invention discloses a low voltage crossing scheme of a double-fed fan based on superconducting magnetic energy storage and improved control, comprising a superconducting magnetic energy storage device and a control strategy matching with the superconducting magnetic energy storage device. A super-conduction magnetic energy storage device comprises a super-conduction coil, a DC-DC Converter, aCapacitor and a Voltage Source Inverter. The superconducting coil is connected in parallel to the rotor side of the doubly-fed induction motor through a DC-DC converter, a superconducting magnetic energy storage side inverter and a filter inductor. and the control strategies include transient voltage control and current backtracking control. In that event of power grid voltage failure, After failure, At that same time, the rotor-side invert and the inverter of the superconduction magnetic energy storage device are switched to the current reverse tracking control and the transient voltage control, Each inverter shares 50% of the rotor overcurrent to ensure that the reactive current is injected into the rotor side by transient voltage control while each inverter does not exceed the current,so that the stator side emits reactive current to support the grid voltage, thereby improving the low voltage ride-through capability of the fan.

Description

technical field [0001] The invention relates to the technical field of double-fed fan equipment, in particular to a low-voltage ride-through method for double-fed fans based on superconducting magnetic energy storage and improved control. Background technique [0002] Wind power generation is a distributed renewable energy power generation system. Wind power generating units generally consist of wind turbines, gearboxes, generators and their control systems. Commonly used wind power generators include squirrel-cage induction generators, doubly-fed induction generators and permanent magnet synchronous generators, in which the squirrel-cage induction generators are directly connected to the grid, the stator of the doubly-fed induction generator is directly connected to the grid, and the rotor passes through The inverter is connected to the grid, and the permanent magnet synchronous generator is connected to the grid through the inverter. In the current wind power market, doub...

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Problems solved by technology

[0006] The invention solves the problem of weak low-voltage ride-through capability of double-fed fans in the prior art, and provides a low-voltage ride-through method for double-fed fans based on superconducting magnetic energy storage and improved control. When applied, the double-fed fan can be equipped with zero The ability of voltage ride-through, in addition, the double-fed wind turbine can also inject reactive power into the grid to support the grid voltage under the fault on the basis of ensuring that various key parameters do not exceed the limit, which can meet the low-voltage ride-through ability of double-fed wind turbines all requirements of

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