Hierarchical control method for ad/dc microgrid with direct voltage recovery character

A technology of DC microgrid and DC voltage, which is applied in the direction of load balance and electrical components in the DC network, and can solve problems such as voltage drop, increase system maintenance cost, and reduce voltage stability

CN104300589AActive Publication Date: 2015-01-21STATE GRID CORP OF CHINA +2
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Patent Information

Authority / Receiving Office
CN · China
Current Assignee / Owner
Publication Date
2015-01-21

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Abstract

The invention relates to a hierarchical control method for an ad / dc microgrid with the direct voltage recovery character. The method comprises two layers of control, wherein in the first layer of control, a direct voltage-active power droop control method is adopted, and even load allocation is achieved; in the second layer of control, a method for compensating for the direct current bus voltage reference value is adopted for the direct current bus voltage drop caused by the droop control, the recovery of the bus voltage is achieved, and the quality of the direct current bus voltage is guaranteed. According to the method, the even power distribution during load changing of a local power source is achieved while the quality of the direct current bus voltage is guaranteed.
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Description

technical field

[0001] The invention relates to a control method in a micro-grid, in particular to a layered control method for an AC-DC micro-grid with DC voltage recovery characteristics. Background technique

[0002] Microgrid refers to a small power generation and distribution system composed of distributed power sources, energy storage devices, energy conversion devices, loads, monitoring and protection devices, etc. It is an autonomous system capable of self-control, protection and management. Adopting the form of AC-DC hybrid micro-grid, many conversion links and conversion devices are omitted, so that the micro-grid structure is simple, the control is more flexible, the loss is reduced, and the economy and reliability of the entire system are improved. In order to realize the connection between the power supply and the load, various methods such as centralized control, master-slave control, current chain control, and average current control are generally adopted. By ...

Examples

Embodiment

[0107] The following uses Digsilent software to illustrate the control strategy of the present invention and its steady-state and transient control effects under the parallel operation mode of two converters. The network topology diagram is as follows Figure 9 shown.

[0108] Both converters adopt voltage recovery control, the reference voltage U0 is 0.7kV but the parameters are different, and other network parameters are shown in Table 1. The DC side is connected with two DC constant resistive loads and a distributed DC power supply. The voltage reference value is 1kV.

[0109] Table 1 Simulation example parameter setting table

[0110]

[0111] At the beginning of the simulation, the two converters distribute the power evenly according to the droop control, and the voltage recovery control starts to work at t=0.5s. At this time, the DC voltage waveform is as follows: Figure 10 As shown, the output power waveforms of the two converters are shown in Figure 11. Depend ...