Hi all.
What is the correct method for calculating the efficiency in a basic bridge rectifier circuit. Basic circuit: AC source > bridge rectifier > bulk cap and resistor load. The power in the resistor is easy. The power delivered from the AC supply is where I have a problem. You can't use the RMS voltage X RMS current , due to the very non linear current waveform. Even VICos(theta) does not even come close to the correct answer. I'll attach a LTSpice sim. That gives the correct answer , but without that I'd be stuck :0)
Using the simulation the power in load (R1) is 39.89W , and the power supplied by V1 is 47.9W. That leaves approx 7W dissipated in the bridge and cap ESR etc. This is totally realistic and what I would expect. However , if you measure the source voltage and current (separately) and calculate the power then you get 21.06 x 3.2 = 67.4W , which is obviously wrong. You would need a phase angle of about 45deg to get VI x Cos(angle) to work , and the phase angle is nowhere near that.
Any pointers to where I'm going wrong would be great :0)
Cheers
Rob
What is the correct method for calculating the efficiency in a basic bridge rectifier circuit. Basic circuit: AC source > bridge rectifier > bulk cap and resistor load. The power in the resistor is easy. The power delivered from the AC supply is where I have a problem. You can't use the RMS voltage X RMS current , due to the very non linear current waveform. Even VICos(theta) does not even come close to the correct answer. I'll attach a LTSpice sim. That gives the correct answer , but without that I'd be stuck :0)
Using the simulation the power in load (R1) is 39.89W , and the power supplied by V1 is 47.9W. That leaves approx 7W dissipated in the bridge and cap ESR etc. This is totally realistic and what I would expect. However , if you measure the source voltage and current (separately) and calculate the power then you get 21.06 x 3.2 = 67.4W , which is obviously wrong. You would need a phase angle of about 45deg to get VI x Cos(angle) to work , and the phase angle is nowhere near that.
Any pointers to where I'm going wrong would be great :0)
Cheers
Rob
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