Pulse Width Modulation Diversion Regulator latest

[jhinshel]

hi
Johnrae, I would be interested in this circuit design - please could you let me have it or put it up on this thread.
Justin

[johnrae]

Justin,
Hopefully I've managed to attach a link to my basic control circuit.
It is crude and is filling a techological gap until such time as I can design and build a proper PWM circuit (probably based on an Arduino)

By way of explanation :

a) the 3-phase output from the turbine is rectified to produce a raw DC voltage ranging from 0-48 volts depending upon turbine speed
b) the SCR is rated at 200 volts 100 amps  (Better to be over-rated to handle extreme conditions)
c) the value of the 470 ohm resistor was selected to permit the relay to energise at around 22 volts
d) the capacitor charges charges to the voltage across the relay prior to it energising
e) once the relay energises the capacitor discharges into the gate of the SCR so turning it on
f) the 100 ohm resistor controls the discharge current from the capacitor to prevent destruction of the relay contact (which it did before adding the resistor)
g) the diode suppresses any transient from the relay to protect the electrolytic capacitor
h) once the SCR is triggered on, it remains latched on until the turbine speed has dropped to virtually zero, when the voltage at the SCR input has dropped to zero and the SCR "de-latches"
i) once the SCR turns on there is no voltage applied to the relay so it de-energises and remains so until the SCR turns off.
j) note that none of the controls are connected to the -ve leg.  All control voltage is derived from voltage appearing across the SCR

I trust this helps

Jack

[cjw]

Jack,

Thanks for the post of the circuit. I had wondered how to do this.

Great simple design that is easy to understand.

Cheers,
Chris

[johnrae]

I omitted to mention that the relay is a 24 volt unit
These pull in at around 18 volts but the addition of the 470ohm resistor increases the pull-in voltage.
I chose 22 purely on the basis that it was greater than 21 but less than 23  -  only joking.  It seemed a reasonable value and represents around 20% of turbine power.
Must get round to sorting out a PWM circuit since I'm obviously wasting wind
jack

[Alan]

http://www.quasarelectronics.com/velleman/k8004-dc-to-pulse-width-modulator-kit.htm

http://www.velleman.eu/downloads/0/illustrated/illustrated_assembly_manual_k8004_rev3.pdf

Page 11 is the circuit diagram.

As supplied in kit form.

Max volts 35 D.C.

Max current 6.5 Amps.

Input offset and span can be adjusted for matching the out put available to the load produced.

If modified so that pin 15 has a voltage less than 35 volts

It can be modified for any generated capacity  / voltage / power you require by changing the
fet T2 and heat sink. Reverse diode D4  and increasing the wattage of resistors 8 – 9 – 10

Regards

Alan