SIMULATED ANALYSIS OF RESONANT FREQUENCY CONVERTER USING DIFFERENT TANK CIRCUITS
Keywords:
- LLC(Inductor Inductor Capacitor), ZCS(Zero Current Switching), Resonance, variable frequency converter, Control Circuit, Supply Circuit, Dead band Circuit, Driver Circuit, IGBT circuit board, High frequency rectifier and filter, IR1(Load Current), VR1(Load Voltage)Abstract
LLC resonant frequency converter is basically a combo of series as well as parallel resonant ckt. For LCC resonant
converter it is associated with a disadvantage that, though it has two resonant frequencies, the lower resonant frequency is in
ZCS region[5]. For this application, we are not able to design the converter working at this resonant frequency. LLC
resonant converter existed for a very long time but because of unknown characteristic of this converter it was used as a series
resonant converter with basically a passive (resistive) load. . Here, it was designed to operate in switching frequency higher
than resonant frequency of the series resonant tank of Lr and Cr converter acts very similar to Series Resonant Converter.
The benefit of LLC resonant converter is narrow switching frequency range with light load[6] . Basically, the control ckt
plays a very imp. role and hence 555 Timer used here provides a perfect square wave as the control ckt provides no slew
rate which makes the square wave really strong and impenetrable. The dead band circuit provides the exclusive dead band
in micro seconds so as to avoid the simultaneous firing of two pairs of IGBT’s where one pair switches off and the other on
for a slightest period of time. Hence, the isolator ckt here is associated with each and every ckt used because it acts as a
driver and an isolation to each of the IGBT is provided with one exclusive transformer supply[3]. The IGBT’s are fired using
the appropriate signal using the previous boards and hence at last a high frequency rectifier ckt with a filtering capacitor is
used to get an exact dc waveform .The basic goal of this particular analysis is to observe the wave forms and characteristics
of converters with differently positioned passive elements in the form of tank circuits. The supported simulation is done
through PSIM 6.0 software tool.
