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press to shut down state. In this state, the PCS blocks IGBT pulse and disconnect the AC
and DC switches.
In the standby state, the PCS blocks IGBT pulse, but closes AC and DC switches, and the
PCS is in hot standby state.
The PCS can switch to different modes, and switch conditions are shown in follow.
figure 9-5 Working mode switching diagram
9.4 Operating Mode
9.4.1 Grid-connected Mode
In the grid—connected mode, the PCS can realize charging and discharging.
Grid-connected constant power (AC), grid — connected constant power (DC), grid — con-
nected constant voltage, and grid—connected constant current;
The grid—connected mode is set by the scheduling instruction and is available in the charg-
ing and discharging state.
9.4.2 VSG Mode
VSG (Virtual Synchronous Generator) control combines the PCS control and synchronous
generator control. It borrows the control methods of ordinary PCS and conventional synchro-
nous generator in terms of control strategy. From the perspective of external input and out-
put, the PCS is equivalent to a synchronous generator. Essentially, VSG frequency droop
control is controlling active power output based on a specific droop slope according to fre-
quency changes. VSG voltage droop control is controlling reactive power output based on a
specific droop slope according to voltage changes. Running parameters that can be set in
the VSG mode include output voltage set value, output frequency set value, active power
setting, reactive power setting, frequency droop factor, and voltage droop factor.
The VSG mode can be set via the PC interface or WEB. The VSG mode has two operation
states: grid—connected state and off-grid state.
9 Operating Mode User Manual
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