Hello All!
This is a first post for me.
I was just analyzing a three-phase diode rectifier circuit - an AC/DC converter. Please see the attached. The source is a wye configuration, and the rectifier involves the use of 6 diodes along with a smoothing capacitor across the load. It is a simple, but pretty sweet circuit. Whenever the phase voltage of any particular phase exceeds the voltage of the positive output terminal, a diode turns on for a fraction of a cycle, recharging the capacitor. Likewise, whenever the phase voltage of any particular phase falls below the voltage of the negative output terminal, a diode turns on for a fraction of a cycle, recharging the capacitor. As long as the capacitance of the capacitor is sufficiently high, the output voltage is essentially constant, and diodes only turn on for a tiny fraction of a cycle every cycle as soon as the output voltage just starts to diminish.
All of which is known, understood, and celebrated.
However, if we assume that the neutral of the source is grounded, then the DC output cannot share the same ground. In theory, this would cause diodes to burn up. In practice, I suspect, this would cause fuses to blow or circuit breakers to trip, etc.
So, my question is this: How do you properly ground the output of the AC/DC converter? i.e. How do you properly ground the load that you connect to the AC/DC rectifier? Or do you just live with a floating reference point? What are the best practices for proper grounding of this circuit?
Thank you.
This is a first post for me.
I was just analyzing a three-phase diode rectifier circuit - an AC/DC converter. Please see the attached. The source is a wye configuration, and the rectifier involves the use of 6 diodes along with a smoothing capacitor across the load. It is a simple, but pretty sweet circuit. Whenever the phase voltage of any particular phase exceeds the voltage of the positive output terminal, a diode turns on for a fraction of a cycle, recharging the capacitor. Likewise, whenever the phase voltage of any particular phase falls below the voltage of the negative output terminal, a diode turns on for a fraction of a cycle, recharging the capacitor. As long as the capacitance of the capacitor is sufficiently high, the output voltage is essentially constant, and diodes only turn on for a tiny fraction of a cycle every cycle as soon as the output voltage just starts to diminish.
All of which is known, understood, and celebrated.
However, if we assume that the neutral of the source is grounded, then the DC output cannot share the same ground. In theory, this would cause diodes to burn up. In practice, I suspect, this would cause fuses to blow or circuit breakers to trip, etc.
So, my question is this: How do you properly ground the output of the AC/DC converter? i.e. How do you properly ground the load that you connect to the AC/DC rectifier? Or do you just live with a floating reference point? What are the best practices for proper grounding of this circuit?
Thank you.