Coordinated AC Voltage Sensorless Control Method for Multiple Inverters

AC voltage sensorless control method has been developed to reduce the inverter cost and improve the operational reliability. But it cannot guarantee the power control accuracy and may output the unwanted reactive power due to the accurate phase angle information absence of grid voltage. To overcome this significant disadvantage, this paper proposes a coordinated ac voltage sensorless control method for multiple inverters, which could be assumed for large-scale PV station, microgrid and etc. In specific, only one of multiple inverters would equip the ac voltage sensor and the rest will not install ac voltage sensors. Doing so, the proposed method can use the recently proposed global synchronous pulse width modulation method to distribute the calculated AC voltage information from the inverter with ac voltage sensor to those without ac voltage sensor for modifying the phase angles obtained by the traditional ac voltage sensorless control. The constructed experimental prototype verified the performance of the proposed method.