Power sharing control method for open-winding dual-inverter photovoltaic power generation system

Abstract

The invention discloses a power equal sharing control method of an open-winding dual-inverter photovoltaic power generation system. Aiming at the problem of uneven power distribution between the two inverters caused by the 120-degree decoupling modulation strategy of the common DC bus open-winding dual-inverter photovoltaic power generation system, the present invention proposes a power equalization based on reactive power compensation A control method, the method obtains the reactive current command value of the inverters by adjusting the active power difference between the two inverters, so as to realize the equal power sharing of the two inverters. Compared with the existing method, the present invention does not affect the power quality of grid-connected current while realizing the control target, and the control method is simple and easy for engineering realization.

Description

technical field [0001] The invention belongs to the control technology of open-winding double inverters in the field of electrical engineering, and in particular relates to a power sharing control method of an open-winding double-inverter photovoltaic power generation system. Background technique [0002] With the increasing power level of photovoltaic inverters, multi-level inverter topology has become a key research object. Compared with the mid-point clamped and cascaded multi-level inverter topologies, the open-winding dual-inverter topology can provide more levels with the same number of switching devices, resulting in less output voltage Harmonics have a higher DC side voltage utilization, so they have received extensive attention from many scholars. [0003] However, when the open-winding dual inverters share the DC bus, it is necessary to suppress the circulating current between the two inverters. A typical solution is to use zero common-mode voltage vector modulati...

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Problems solved by technology

[0008] The purpose of the present invention is to solve the problem of uneven distribution of active power between the two inverters that exists when the common DC bus open-winding double inverter adopts mutual difference 120 degree decoupling modulation, and proposes an open-winding based on reactive power compensation A power sharing control method for a dual-inverter photovoltaic power generation system. This method can realize the power sharing of dual-inverters without affecting the power quality of the grid-connected current, and the implementation process is simple, which overcomes the limitations of existing technical solutions. insufficient

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