Shunt active filtering by constant power load in microgrid based on IRP p-q and CPC reference signal generation schemes

Constant power loads (CPLs), interfaced by active rectifiers can be used to provide reactive power for voltage stability in a microgrid they are part of. In addition, they have the potential to minimize the harmonic issues caused by the power electronic non-linear loads. This article investigates the possibility of using a CPL for shunt active filtering in addition to consuming a constant active power from the source. Reference signal generation techniques for shunt compensator or CPL are based on instantaneous reactive power (IRP) p-q theory and the theory of current´s physical components (CPC), in synchronous rotating reference frame. CPL control is based on vector control method. IRP p-q theory based reference signal generation technique uses filters to extract the desired current components. CPC utilizes frequency domain methods to compute the current references. In this paper, discrete Fourier transform (DFT) is used to extract the reference signal for shunt compensation by CPL. Simulation results show that the CPL performs shunt active filtering very efficiently. It is also observed that the source current distortion is further reduced when CPL acts as a load interface compared to the case when it behaves as shunt active compensator only.