Control of solar photovoltaic integrated UPQC operating in polluted utility conditions

This study proposes a control approach based on second‐order generalised integrator (SOGI) and delayed signal cancellation (DSC) for improved control of single‐phase two‐stage solar photovoltaic array integrated unified power quality conditioner (UPQC‐SPV). The SPV array is integrated to the DC link of UPQC‐SPV through a simple boost converter. The boost converter is controlled using a maximum power point tracking algorithm to operate SPV array at its peak power point. The series compensator control is based on extraction of point of common coupling voltage template using two cascaded SOGI (CSOGI) band‐pass filter. The shunt compensator control is based on extraction on fundamental load current. As the load current is highly non‐linear, a combination of CSOGI and DSC is used to extract fundamental active component of load current, from which the reference signal for shunt compensator is generated. This approach allows good accuracy in extraction of fundamental component of load current without sacrificing the dynamic performance. The performance of UPQC‐SPV is verified experimentally on a prototype developed in the laboratory under dynamic conditions such as load change, voltage sags/swells and irradiation variation.