 DEPARTMENT OF ELECTRICAL POWER ENGINEERING

COLLEGE OF ENGINEERING

POWER ELECTRONICS PWM Inverter (Bipolar) : The full bridge inverter shown has a switching frequency sequence that produces a square wave voltage across a series RL load using bipolar PWM.

Select the amplitude modulation ratio, ma: | 0.1 | 0.2 | 0.3 | 0.4 | 0.5 | 0.6 | 0.7 | 0.8 | 0.9 | 1.0 |

Here, the amplitude modulation ratio ma = 0.8

Determine:

• a.Amplitude of the fundamental frequency voltage
• b.Amplitude of the fundamental frequency voltage
• c.Power absorbed by the load resistor
• d.Total harmonic distortion (THD) of the load current

 Please enter the input value: DC input: V frequency modulation ratio, mf: Resistance: ohm Inductor: mH Switching Frequency: Hz

The amplitude of each current is determined from

In = Vn /Zn

Power at each frequency is determined from

Pn = I2rms R

a)

 Amplitude of the fundamental frequency voltage = V1 = ma*Vdc = V

b)

 Amplitude of the fundamental frequency current = I1 = V1/Z1 = A

c)

 With mf = The first harmonics are at n = , ,
 n fn(Hz) Vn(V) Zn(¦¸) In(A) In,rms(A) Pn(W) 1

 Power absorbed by the load P = ¦˛Pn = W

# Click for explanation.

d)

 THDI = = %