On its AC side near sinusoidal current waveforms and AC four quadrant operation can be obtained leading to a high quality power exchanged between the converter and the mains. The use of AC filters becomes unnecessary. The rectifier DC voltage must be regulated to a constant value. In this paper three solutions for the DC voltage control are presented. In the first solution, the DC voltage is controlled acting upon the quadrature component of the converter fundamental Park's voltages with relation to the mains voltages.
Slow responses are necessary because of stability reasons.
Also, load power variations produce both active and reactive power variations in the converter AC side. To improve the DC voltage response a second control solution is presented. The converter currents in Park's coordinates must be controlled. The DC voltage is controlled by controlling the direct Park's current component and thus acting only on the active power of the converter AC side. Faster responses are achieved.