Power Electronics - Inverters Solved Example

A single phase half bridge inverter has a resistance of 2.5Ω and input DC voltage of 50V. Calculate the following −

Solution −

a. The RMS voltage occurring at the fundamental frequency

$E_{1RMS}=0.9\times 50V=45V$

b. The power Output

RMS output voltage $E_{ORMS}=E=50V$

Output power $=E^{2}/R=\left ( 50\right )^{2}/2.5=1000W$

c. Peak current and average current

Peak current $I_{p}=E_{0}/R=50/2.5=20A$

Average current$=I_{p}/2=20/2=10A$

d. Harmonic RMS voltage

$E_{n}=\left \{ \left ( E_{ORMS} \right )^{2}-\left ( E_{1RMS} \right )^{2} \right \}^{0.5}=\left [ 50^{2} -45^{2}\right ]^{0.5}=21.8V$

e. Total harmonic distortion

$E_{n}/E_{1RMS}=21.8/45=0.48\times 100\%=48\%$