Droop mode precautions

Since firmware D141, droop mode has been added to PWS2-30K/M, to provide a non-communication off-grid parallel operation solution.

Single phase firmware can supports three sets of inverters droop mode yet.

To write register 750(0x02EE) and 756(0x02F4), authorization must be granted first, by writing 2007 to register 4007(0x0FA7) and 2016 to register 4008(0x0FA8).

The PWS2-30K must be set to 3P3W, 750(0x02EE)= 1; and NO neutral line connected

To enable droop mode, set register 756(0x02F4) to 1

After enabling droop mode, a hard reboot is required., write 1 to register 657(0x0291) to reboot the software. make sure the inverter is not running at this moment.

A delta-wye transformer is required if 277V or 220V single phase load is required.

When multiple PWS2-30K/M are used for off-grid droop parallel operation, there must be one PWS2-30K establishing AC voltage first, and then the others can be started.

The maximum quantity of PWS2-30K/M verified to be working for off-grid droop parallel operation in one microgrid is 9 units (because we can only obtain 9 units in the lab)

When droop parallel operation implemented, the length of the cables from the PWS2-30K/M should be as same as possible.

The droop mode will bring voltage and frequency fluctuation (90%~110%)

The droop mode will bring some circulating current between each PWS2-30K/M, if the load is low in off-grid microgrid, the currents of each DC side of the PWS2-30K will be fluctuating not more than of ±5%