A novel current detection algorithm with predictor for shunt active power filters in harmonic elimination, reactive power compensation and three-phase balancing under steady-state and transient conditions

A novel current detection technique with predictor is presented for generation of a real-time estimate of the fundamental component of the distorted input current to an three-phase diode bridge rectifier with resistance or inductance loads, which is suitable to be compensated with shunt active power filter (SAPF). This allows for accurate calculation of cancellation references for SAPF operating under steady-state and transient conditions. Improved transient performance is obtained by using the predictor. Different compensating current references can be accurately and easily obtained by adopting the proposed algorithm based on time domain. It ensures that a shunt APF can very well achieve different compensation purposes. Moreover, it is very easy to implement this algorithm in a Digital Signal Processor (DSP). Simulation results obtained with Matlab and testing results on an experimental SAPF show good steady-state performance and excellent transient performance that far exceeds that of conventional identifier, such as instantaneous reactive power theory or DFT.