 DEPARTMENT OF ELECTRICAL POWER ENGINEERING

COLLEGE OF ENGINEERING

POWER ELECTRONICS Harmonic Control of Full Bridge Inverter Example: The full bridge inverter shown has a switching frequency sequence that produces a square wave voltage across a series RL load. Assuming that ¦Á = 30 degrees.

Determine:

• a.Amplitude of the fundamental frequency voltage
• b.DC input voltage
• c.Amplitudes of the Fourier series terms for load voltage
• d.Amplitudes of the Fourier series terms for load current
• e.Total harmonic distortion (THD) of the load voltage and the load current

 Please enter the input value: Fundamental frequency current amplitude: A Resistance: ohm Inductor: mH Switching Frequency: Hz

The amplitude of load voltage is determined from

Vn = (4 Vdc* cos(n¦Đ)) / n ¦Đ

The amplitude of each current is determined from

In = Vn /Zn

a)

 Amplitude of the fundamental frequency voltage = V1 = V

b)

 DC input voltage = Vdc = V

See Fourier Series Analysis

c)and d)

 n fn(Hz) Vn(V) Zn(¦¸) In(A) 1 3 5 7 9 11

e)

 THDv = = %

 THDI = = %