Voltage control system and method for grid-connected point of microgrid based on power coordinated regulation

Abstract

The invention belongs to the field of microgrid grid-connected point voltage control, and provides a microgrid grid-connected point voltage control system and method based on power coordinated regulation, which is suitable for a microgrid under grid-connected conditions. The system includes: a voltage stabilization compensation current loop, which sends the difference between the instantaneous amplitude of the voltage at a given point PCC and a given voltage amplitude reference value into the voltage stabilization compensation current loop; after the first PI adjustment in the voltage stabilization compensation current loop The signal adjusted by the controller is added with the signal output by the active current loop to obtain the active current reference value; the difference between the active current reference value and the given d-axis current value is input to the second PI regulator, and the output signal is sent to the SPWM pulse width A modulation module, the generated modulation signal is used to control the voltage or power of the grid connection point; the input signal of the active current loop includes a given reference value of active power and a d-axis voltage value.

Description

technical field [0001] The invention belongs to the field of voltage control of a grid-connected point of a microgrid, and in particular relates to a system and method for controlling the voltage of a grid-connected point of a microgrid based on power coordinated regulation. Background technique [0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art. [0003] The point of common coupling (PCC) voltage stability between the microgrid and the large grid is a key issue in the development of microgrid technology. When the PCC voltage fluctuates, the grid-connected inverter can change the active power on the line. Or the flow of reactive power for voltage control at the PCC. [0004] When only changing the flow of active power at the grid-connected inverter to regulate the voltage at the grid-connected point, it is impossible to maximize the transfer of the active power of the mic...

AI Technical Summary

Problems solved by technology

[0004] When only changing the flow of active power at the grid-connected inverter to adjust the voltage at the grid-connected point, it is impossible to maximize the transmission of active power from the microgrid to the distribution network

When only changing the flow of reactive power at the grid-connected inverter to adjust the voltage at the grid-connected point, it is necessary to consider the power factor at the PCC when the microgrid is in grid-connected operation. In a microgrid with a lower voltage level, the reactive power The flow has little effect on the voltage at the PCC. To restore the PCC voltage to normal, a large amount of reactive power is needed as a support, which may cause overcompensation and reduce the power factor.

Changing the active or reactive power alone to adjust the grid-connected point voltage will also increase the burden on the capacity of the grid-connected inverter and increase the power loss of the inverter

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