Re: Aw: Re: AW: Re: Re: AW: [EVGRAY] Re: buck plug ...

Body

Hi Sven,

I wonder what is being measured in "High_Impedanz_Voltage_plus_to_AC.bmp". The yellow voltage looks like the voltage in forward conduction across one of the diodes and the freewheeling flyback voltage of an inductor. The ground is then floating or the signal is inverted. The current looks like a 50Hz fully rectified AC signal being inverted but with its normal peak or top at ground level and the normal zero value being negative. If my guess is correct the yellow signal is the voltage between the cathode and anode of either D3 (ground at cathode of D3) or D4 (if ground is right hand side AC and common connection between D3 and D4). The time that this signal starts going negative is when the capacitor is fully charged. I.e. the flyback pulse of the inductor stops running. In the below image the signals are turned upside down for clarifying this. This also makes me realize that the magenta curve is the current from a saturating signal and not from a sine curve. The green boxes are the periods where D3 is conducting. The red curves are the periods where D1 is conducting and the capacitor is being charged from the AC source. This leaves no time without current going to the capacitor as the inductor is running in continuous mode. I.e. the inductor is never fully demagnetized. The green boxes represents the periods in time where no current is received from the input AC to the top half of the circuit.




Regards
Ole
 

---In [email protected], <s.friedrich@...> wrote :

 Hi Ole,
 
 I do not know how to write here it does not matter. I try it again by email:
 
 I can not get on with the diode plug and have just connected a FWBR s.der coupling capacitors and sometimes played with different loads and just times with the scope measured at various measuring points as the SCR stops working.
 
 I noticed that actually every diode plug must be charged twice before it triggers to think I work as Hector says. I hope he rectifies me.
 
 I've always wondered why he always thought to unload 30x SCR Minus and unload 30x SCR plus. There is a sine wave of 2 half-waves, if it is discharged each time, the value at 60Hz would be twice as high.
 
 I hope this message comes over otherwise I give it up.
 
 regards
 
 Sven   Gesendet: Donnerstag, 15. Februar 2018 um 03:41 Uhr
 Von: "onielsen@... [EVGRAY]" <[email protected]>
 An: [email protected]
 Betreff: Re: AW: Re: Aw: Re: AW: [EVGRAY] Re: buck plug ...
    
 Third time.
 
 Hi Sven,
 
 Here is one of your schematics which will do for describing an idea for peak detection. I hope this message doesn't get truncated.
 
 The current through the freewheeling diodes can be monitored by measuring the sign of the voltage across them. By watching when the voltage (U_pos) across D3 is negative this tells that the current through D1 has stopped and the stored energy of inductor L1 is being 'discharged' or actually demagnetized. When the inductor L1 is fully demagnetized the U_pos voltage stops being negative and the capacitor C1 is fully charged. This is the time for discharging C1 by triggering the T1 SCR.
 
 A similar circuit is used for triggering the negative cycle. By doing it this way the triggering point will always happen when the charging current to the capacitors stop flowing.
 
 Regards
 Ole
 
 
 ---In [email protected], <s.friedrich@...> wrote :
    
 Hello Ole, thank you for your comments. I would like to switch to the peak first, unfortunately, the circuit works together then I could imagine if I switch later, I get back to a clean sine wave without distortion. I would like to switch the voltage almost to zero a short peak, which is possible with reactive energy. By impedance reduction, of course, I can switch later or is it now only the impedance that makes it dependent? I think that I discharge the capacitors so now when the current is in zero crossing, otherwise the energy would be reflective to the load because additional current is charged into the capacitors. Greetings Sven
  
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