Power compensation based on digital predictive current controlled three-phase bi-directional inverter with wide inductance variation

This paper presents power compensation based on digital predictive current controlled three-phase bi-directional inverter with wide inductance variation. The three-phase bidirectional inverter can fulfill both real power and reactive power compensation for ac grid. With the proposed control, the inverter can track sinusoidal reference currents precisely with unity power factor or power factors -0.5 ~ +0.5, and it is allowed to have wide inductance variation, reducing core size significantly. In the design and implementation, the inductances corresponding to various inductor currents are measured and tabulated into a single-chip microcontroller for tuning loop gain cycle by cycle, ensuring system stability. Moreover, a one-phase shift detection method for anti-islanding operation based on the proposed control is also presented. Measured results from a 10 kVA 3ø bi-directional inverter have confirmed the feasibility of the discussed control approach and detection method.