A DC capacitor voltage control method for active power filters using modified reference including the voltage ripple derived from a theoretical analysis
This paper proposes a new dc capacitor voltage
control method suitable for active power filters equipped with a
small dc capacitor. The proposed control method calculates the
theoretical energy stored in the dc capacitor and provides it to the
dc capacitor voltage feedback controller as its energy reference.
As a result, the proposed method has capability to regulate the
mean value of the dc capacitor voltage without any degradation
in harmonic compensation even when a small dc capacitor and
a high feedback gain are applied. Furthermore, application of
a high feedback gain to the proposed method makes it possible
to suppress the capacitor voltage fluctuations effectively without
any performance deterioration in the harmonic compensation.
Experimental results confirm a good harmonic compensating
performance when applying a high-gain feedback controller to
an active power filter with a small dc capacitor. The results also
demonstrate a significant improvement in the capacitor voltage
regulation even when a sudden load change occurs.