NEWMAR 115 12 20 AU FullWave Rectifier with

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NEWMAR 115 – 12 – 20 AU Full-Wave Rectifier with Choke-Input Filter ECE 442

NEWMAR 115 – 12 – 20 AU Full-Wave Rectifier with Choke-Input Filter ECE 442 Power Electronics 1

Choke-Input Filter ECE 442 Power Electronics 2

Choke-Input Filter ECE 442 Power Electronics 2

DC Operation + + Vdc V’dc - - V’dc = Vdc(Rinductor) / (Rinductor +

DC Operation + + Vdc V’dc - - V’dc = Vdc(Rinductor) / (Rinductor + Rload) ECE 442 Power Electronics 3

AC Operation (approximate) Normally, make Xcapacitor << Rload ECE 442 Power Electronics 4

AC Operation (approximate) Normally, make Xcapacitor << Rload ECE 442 Power Electronics 4

Approximate the Circuit + + Vr V’r - Usually, Xinductor >> Xcapacitor V’[rms] =

Approximate the Circuit + + Vr V’r - Usually, Xinductor >> Xcapacitor V’[rms] = (Xcapacitor / Xinductor)(Vr[rms]) ECE 442 Power Electronics 5

Full-Wave Rectifier Output frequency = twice the line frequency Second Harmonic (first ac component)

Full-Wave Rectifier Output frequency = twice the line frequency Second Harmonic (first ac component) ECE 442 Power Electronics 6

2π(120) ECE 442 Power Electronics 7

2π(120) ECE 442 Power Electronics 7

“Critical” Inductance, Lc Must keep the load current flowing for the complete cycle of

“Critical” Inductance, Lc Must keep the load current flowing for the complete cycle of the input voltage The dc load current must be > the peak value of the ac component of the load current ECE 442 Power Electronics 8

Minimum Inductance Lc ECE 442 Power Electronics 9

Minimum Inductance Lc ECE 442 Power Electronics 9

“Bleeder” Resistor • The bleeder resistor provides 2 functions – keeps a minimum current

“Bleeder” Resistor • The bleeder resistor provides 2 functions – keeps a minimum current flowing through the inductor – discharges the filter capacitor after turn-off • Rbleeder = R 1 = the largest value of Rload – sets the maximum value of inductor L ECE 442 Power Electronics 10

Range of values for the Filter Choke • NEWMAR 115 – 12 – 20

Range of values for the Filter Choke • NEWMAR 115 – 12 – 20 AU Power Supply • Lmax > R 1/1000 = 5 m. H 50 m. H • Lc >= R 1/1000 = (12 V/20 A)/1000 = 0. 6 m. H ECE 442 Power Electronics 11