Reactive power, imbalance and harmonics compensation using d-statcom with a dissipativity-based controller

We present a solution to the problem of reactive power compensation and harmonic compensation in a general case when both the source voltages and the load currents are unbalanced and contain an arbitrary number of harmonics. For the compensation purpose, a d-statcom is connected in parallel to inject the required currents, so that from the source terminals the same apparent resistance is observed in all phases and at all frequencies. A controller based on the ideas of passivity theory, to which we have added adaptation to compensate for the unavoidable uncertainty in some of the parameters, is suggested as a solution. One of the major advantages of this solution compared to conventional ones is that we are able to perform precise tracking (also for high order harmonics) even in the presence of a relatively low switching frequency, i.e., in presence of an active filter with limited bandwidth. Simulation results are provided to illustrate the performance of our controller.