Energy conversion system and method with negative-sequence current compensation mechanism

Abstract

The invention discloses an energy conversion system and method. The energy conversion system comprises a direct current bus, a converter module and a converter control module, wherein the direct current bus is used for receiving a direct current coming from a power source, and the converter module is used for converting the direct current on the direct current bus into an alternating current. The converter control module is used for producing a first command signal according to an active power command signal and an active power feedback signal, producing a second command signal according to a reactive power command signal and a reactive power feedback signal, and producing a first negative-sequence current correction signal and a second negative-sequence current correction signal according to a negative-sequence current command signal and a negative-sequence current feedback signal on a power grid, wherein the first negative-sequence current correction signal and the second negative-sequence current correction signal are used for compensating a negative-sequence current, and the first command signal and the second command signal are adjusted based on the first negative-sequence current correction signal and the second negative-sequence current correction signal respectively. The converter control module is further used for producing a control signal based on the adjusted first command signal and the adjusted second command signal so that the converter control module can be driven to operate under the function of the control signal.

Description

technical field [0001] The embodiments disclosed in the present invention relate to an energy conversion system and method for providing electric energy to a power system, and in particular to a negative-sequence current compensation mechanism and method for an energy conversion system. Background technique [0002] Basically, the share of electricity generated by renewable energy generation systems, such as photovoltaic power generation systems, is becoming more and more significant all over the world. A general photovoltaic power generation system includes one or more photovoltaic arrays, and each photovoltaic array includes a plurality of interconnected photovoltaic battery units, which can convert solar radiation energy into DC power. In order to realize the grid-connected power generation of the photovoltaic array, a converter module is usually used to convert the DC power generated by the photovoltaic array into AC power that can be transmitted by the grid. [0003] T...

AI Technical Summary

Problems solved by technology

In this way, when a fault occurs in the power grid, such as a single phase fault (single phase fault) or the overall unbalance of the three-phase system, the resulting negative sequence current may affect the stability of the system

Specifically, a large negative sequence current may limit the positive sequence current output by the AC output terminal, which may cause the output of the positive sequence current to fail to meet the needs, and this makes the energy conversion system unable to meet the design needs of the grid

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