Sensorless Control for DC-Parallel Active Power Decoupling in PV Microinverters

Active power decoupling (APD) is a highly adopted technique for compact and reliable single-phase inverters to eliminate the undesired ac power drawn from the dc port. Typical operation of APD circuits requires the use of additional sensors measuring APD states to ensure proper decoupling. The additional voltage and current sensors add to system cost and hardware design complexity. This article proposes a sensorless control approach that provides proper control of the APD without the use of additional sensors. The proposed predictive power decoupling control is analyzed together with the operating principle of the APD, and two types of error correctors are introduced to improve the control accuracy and reduce the reliance on the circuit component parameters. The proposed approach provides equally good power decoupling performance compared to traditional sensor-based control strategies while improving the dynamic response. The proposed approach is experimentally verified using a 30-60 V parallel APD circuit and 200 W microinverter hardware prototype.