A controller suitable for grid-connected inverters and a power supply method for secondary systems

Abstract

The invention discloses a controller suitable for a grid-connected inverter and a power supply method of a secondary system. A transformer unit converts power grid voltage into alternating currents and then outputs the alternating currents through a first alternating current output end, the alternating currents are converted into direct currents through a rectification unit and a capacitor filtering unit and then are output to the capacitor filtering unit through a first direct current output end to be stored and filtered, and the direct currents are converted into second direct currents through a direct current conversion power source and then are output through a second direct current output end. The controller suitable for the grid-connected inverter and the power supply method of the secondary system are provided with at least three voltage output ends which respectively obtain 220V alternating direct voltage, 300V direct current voltage and 24V direct current voltage to supply power to various secondary devices in the grid-connected inverter, meanwhile, have an energy-storage function and keep stable voltage output of each output end.

Description

technical field [0001] The invention belongs to the field of electric energy conversion, and in particular relates to a controller suitable for a grid-connected inverter and a power supply method for a secondary system. Background technique [0002] As the core equipment of the new energy power generation system, the grid-connected inverter has become the key factor of the whole system in terms of its capacity, performance and cost. In order to meet the requirements of the power system for the low-voltage ride-through performance of the grid-connected inverter, the traditional grid-connected inverter usually uses an uninterruptible power supply (UPS) as the controller of the grid-connected inverter and the power supply of the secondary system. The uninterruptible power supply (UPS) as the controller of the grid-connected inverter and the power supply of the secondary system usually only has one voltage output terminal, and has the following disadvantages: [0003] New energ...

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Problems solved by technology

[0004] The cheap backup UPS has only one output voltage source, low reliability, no voltage stabilization function, and long conversion time, which seriously affects the reliability of the grid-connected inverter. Although the performance of the online UPS is slightly better, the cost is relatively high. High, and still have reliability issues

[0005] Some UPSs do not have the function of power restart and over-discharge protection. When the power grid is out for a long time, the service life of the internal battery is likely to be reduced due to over-discharge. When the power grid is turned on again, the maintenance personnel of the power station are required to turn on the inverter one by one. The UPS power supply of the device not only increases the workload, but also has potential safety hazards

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