Phase angle balance control for harmonic filtering of a three phase shunt active filter system

This paper proposes a new strategy for harmonic filtering of a three-phase shunt active filter system. The shunt harmonic filter's control objective is defined as: balance the phase angle of the input current with the phase angle of the line frequency component of the load current. This objective is achieved in discreet implementation without sensing the input voltages. The controller uses a phase shifting method on the sensed input current and then applies the resistor emulator type input current shaping strategy on the phase-shifted current. In implementation Texas Instrument's DSP based unit TMS320F240 EVM is used as the digital hardware platform. The control algorithm is computationally simple yet the harmonic filtering performance is high. The analysis, simulation and experimental results of a three-phase shunt active filter prototype on a 25A nonlinear load are presented.