Secondary control method for AC/DC hybrid microgrid based on unified coordination factor

Abstract

The invention discloses a secondary control method for AC / DC hybrid microgrid based on unified coordination factor. The secondary control method comprises the following steps of: the step 1, calculating a power coordination factor of each distributed micro-source; the step 2, obtaining a unified coordination factor in each sub microgrid, and sending the unified coordination factor to each distributed micro-source; the step 3, calculating the power compensation value of each distributed micro-source in the AC sub microgrid and the power compensation value of each distributed micro-source in theDC sub microgrid; the step 4, calculating the power compensation value of an intermediate converter; and the step 5, taking each power compensation value obtained through calculation as the feedbackinput quantity of primary control to regulate the power distribution. When the unified coordination factor is transmitted, the low-bandwidth communication is achieved, the design cost of the communication system is reduced, the unified coordination factor is adopted to compensate the primary control input quantity, the uniform distribution of power in the AC / DC hybrid microgrid is achieved, and the power distribution process is more flexible.

Description

technical field [0001] The invention belongs to the technical field of AC-DC hybrid micro-grid control, and in particular relates to a secondary control method for AC-DC hybrid micro-grid based on a unified coordination factor. Background technique [0002] The AC-DC hybrid microgrid is an independent power generation and distribution system that includes both AC and DC sub-microgrids and connects the buses on both sides with an intermediate converter. It has the following advantages: 1) AC and DC distributed micro-sources and loads are separated Located in the sub-microgrids on both sides, it realizes the personalized power supply demand for users and reduces the multi-layer power electronic conversion link; 2) The power between the AC and DC sub-microgrids can flow in both directions, and each sub-microgrid can also operate independently , so the AC-DC hybrid microgrid is more compatible, and it is an emerging hot technology that makes full use of new energy and realizes p...

AI Technical Summary

Problems solved by technology

[0003] The AC / DC hybrid microgrid has no main grid support, and its power coordinated control depends on the coordinated control of distributed micro-sources with power electronic converters as the interface. Since the droop control can be realized in the state of no communication, in the sub-microgrid control It has been widely used; however, the traditional droop control is susceptible to the influence of control parameters and line impedance differences, and the power distribution accuracy of the system is low. Under disturbances such as new energy output changes and load switching, the AC frequency and voltage of the hybrid microgrid will shift, which indirectly affects the power distribution of the hybrid microgrid. , it is easy to cause the power sharing problem of the system, so in order to achieve more flexible and precise power coordination, the secondary control for the whole network coordination is very important

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