In this paper, the output impedance of a non-isolated boost
converter is increased at 100 Hz by using an internal
current feedback. Therefore in a two-stage power converter,
the low-frequency current ripple of the single-phase inverter
does not get into the input of the boost converter. The
simulation and experimental results show that the maximum
low-frequency current ripple at the input of the boost
converter is less than 1.8% with the designed controller.
The controller response time is so slow that the output over/
undershoot is more than 45% in the step load conditions.
To overcome this problem, a non-linear compensator is
used in series with the PI controller of the voltage loop.
The compensator damps the over/undershoots to 7.4% and
limits the transient time to 300 ms. Thus, with the designed
controller and the proposed compensator and without using
additional devices, both the low-frequency current ripple is
reduced to 1.8% at the input of the boost converter and the
over/undershoot of the output voltage is limited to 7.4% in
the step load condition. If the non-linear compensator was not
used, a 30 mF bulky DC capacitor is required to prevent a
severe over/undershoot of the DC-link voltage whereas,
with the proposed controller, just a 1.9 mF capacitor was
used for the DC link.