Micro-grid control mode

Microgrid includes the following two aspects:

Overall control strategy of (1) microgrid

There are two common control strategies for microgrid: master-slave operation and master-slave operation.

Point to point control.

(2) Control strategy of micro power supply

Because microgrid is based on power electronics technology, the micro-power supply in microgrid is highly controllable and difficult to control.

The control strategies of micro-power supply can be divided into three categories: constant power control, droop control and constant voltage and constant frequency control. they

The control idea of can be described by figure 1- 1, which shows the frequency drop characteristics and voltage drop.

characteristic curve

(A) master-slave control mode

Master-slave control mode means that when the microgrid is in island operation mode, one of the distributed power sources adopts constant voltage and constant frequency control (V/F control for short) to provide voltage and frequency reference for other distributed power sources in the microgrid, and other distributed power sources can adopt constant power control (P/Q control for short). The distributed power controller with V/F control is called master controller, and other distributed power controllers are called slave controllers.

(2) Point-to-point control mode

Peer-to-peer control mode means that all distributed power sources in the micro-grid have the same position in control, and there is no master-slave control relationship between controllers. Each distributed power source is controlled according to local information such as point voltage and frequency connected to the system. For this control mode, the strategy selection of distributed power controller is very important, and the common method is droop control.

(3) Hierarchical control mode

The hierarchical control mode is generally equipped with a central controller, which is used to send control information to the distributed power supply in the microgrid. The central controller first predicts the power generation and load demand of distributed power sources, then makes corresponding plans, and adjusts the operation plan according to real-time information such as voltage, current and power.