In these problems it asks us to find the worst-case rms currents of the inductor, MOSFET and diode. When it refers to rms currents is that over a line cycle such as in Table 18.3?
Furthermore, the expressions in Table 18.3 neglect the effect of switching ripple. Does this mean that we cannot use the expressions given in Table 18.3 and that we need to derive new expressions that take into account the switching ripple with the inductor that we have chosen?
RMS currents are over a line cycle. You may neglect ripple and use Table 18.3. The effect of ripple on RMS currents in CCM is relatively small, recall Table 3.1.
ReplyDeleteEquation 18.121 for the rms diode current contradicts what table 18.3 gives for CCM Boost rms diode current. which one is correct?
ReplyDeleteBoth equations are correct. 18.121 expresses the diode RMS current in terms of Iac,rms (the ac line rms current). Table 18.3 expresses the diode RMS current in terms of Idc (the dc load current).
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