DEPARTMENT OF ELECTRICAL POWER ENGINEERING

COLLEGE OF ENGINEERING

POWER ELECTRONICS

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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 = = %

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