A DSP-based implementation of an instantaneous current control for a three-phase shunt hybrid power filter

This paper presents the design and implementation of an instantaneous current control technique for a three-phase shunt hybrid power filter (SHPF) to compensate harmonics generated by non-linear loads. The control of the SHPF is based on synchronous reference frame (SFR) method. The SHPF consists of a small-rated voltage source inverter (VSI) in series with an LC passive filter. The proposed control algorithm of the SHPF requires less number of current sensors compared to the instantaneous reactive power theory based current control algorithm, which resulting in an overall cost reduction. Proportional–Integral (PI) controller is used to control the SHPF dc-bus voltage. The inner loops ensure the shaping of the ac currents, through the control of dq current components. The outer loop regulates the dc-bus voltage to its set reference and provides the current reference to the inner current loops. The SHPF can maintain the low level of dc-bus voltage at a stable value below 50V, which is one of its advantages in comparison to the conventional hybrid power filter. The systems performance, during both nominal and severe operating conditions, are then evaluated in real-time using the dSPACE DS1104 controller board, supported by a Matlab/Simulink Real-Time Workshop environment.