6 Battery Tesla Switch - Power Mosfet Circuit - Uses No Schottky Power Diodes

[BediniBattery]

This is the ultimate solid state tesla switch circuit.

I have eliminated all of the schottky power diodes which means that there is no significant component heating & no diode resistance to worry about.

All of the switching is done using power mosfets in their very low on resistance states which means very high currents can flow.

There are 4 diagrams, 2 are for the tesla switch itself A & B, with C the 555 Astable & D the Isolated 12 Volt Regulators.

Everything you need to build this circuit is shown below.




The circuit uses a total of six, 12 volt lead acid batteries to power the load.

3 batteries are wired in series to create 36 volts.
The total discharge current is 30 Amps.

3 batteries are wired in parallel to create 12 volts
The total charge current is 10 Amps per battery.

20 Amps are lost to the environment as heat or work done by the load.
This is the amount of energy that the environment needs to replace to keep the tesla switch running.

A switching circuit is used to set the frequency by which the batteries are changed from series to parallel.
When the switching frequency is high enough, the battery voltage should begin to increase under load.

The copper wiring must be constructed from hundreds of thin copper strands, whilst keeping the circuit resistance to an absolute minimum.
All of the connectors should be high quality copper or silver.

The output voltage across the load will be approximately 24 volts, & this will have to be regulated in someway using the 555 switching circuit.
The capacity of the batteries should be upwards of 40 amps, a small car battery is suitable.
The batteries need to deliver 30 Amps through the load, while only getting 10 Amps charging.
All of the batteries should have equal capacity & be in good condition.

The mosfet drive circuits use isolated 12 volt regulated supplies which can deliver 50 mA.
Dc to dc converters are available ready built, but you can make your own if you need more control over the circuit.

The n type mosfet gates are driven between 0 volts & + 12 volts using transistor pairs, in the push pull fashion.
Logic mosfets do not offer any advantage in this circuit, but they can be used if the gate voltage is held within its maximum swing.

You can place many n type mosfets in parallel to reduce the circuit resistance.
The push pull technique enables very fast charging & discharging of the mosfet gate capacitance, so paralleling mosfets is not a problem.

There are no schottky power diodes used in this circuit because they have been replaced by power mosfets.
There is no significant voltage drop across any of the switching devices.
There is no heating of the switching devices since the mosfets have very low on resistance.
There are no diodes placed in the high current path only mosfets with very low on resistance states.
There is no current flow through the mosfet internal diodes, it is all done through the mosfet channel.
There is no need to use large heatinks to cool any of the components.
Very little electrical power is required to run the switching circuits, less than 10 watts in total.

This tesla switch circuit works very efficiently indeed & has much greater potential of being able to deliver extreme power outputs.
If the total circuit resistance can be reduced significantly to less than 0.1 Ohm & a load of 0.4 Ohm or less is connected, over 1 Kilo Watt of free electrical energy can be obtained.

All of the circuit components are constantly switching on & off & are only being used 50 % of the time.
This circuit can be used to build switched capacitor charging circuits, which work in the same way as the tesla switch.

The opto isolator used in the circut diagram is the 4N25.
It is essentially a normal npn transistor, which is controlled entirely using an internal LED.
The resistor values on the 4N25 collector are between 2k2 to 3k3.
The internal LED requires a 1K or 470R, however this must be chosen depending upon the switching frequency.
The opto isolator diode drops 1.13 volts with a current of 10.8mA, which means they can be placed in series if running off a 12 volt supply.
The base of the photo transistor is left unconnected.
Even though the 4N25 is a slow device, it has been tested to function properly between 100 to 1Kz.
There is no need to use a schmitt trigger opto coupler device.

A number of opto isolator transistors have been placed in parallel.
This is to make absolutely sure that none of the mosfets can turn on at the wrong time.
There is a very short time delay between switches, which is controlled entirely by the transistors themselves.
The switching delay is automatically controlled & lasts 1 micro second.

The transistors used are : npn BC547 & pnp BC557.
The mosfets are all n-type IRFP064N with 50 Amp + drain to source current rating, very low on resistance with 55 volt working voltage.

- http://www.ebay.co.uk/sch/i.html?_from=R40&_trksid=m570.l2736&_nkw=IRFP064N -
- http://www.datasheetarchive.com/IRFP064N+equivalent-datasheet.html -

The mosfets have integrated zener diodes which do not interfere with the circuit operation.

When the mosfet is turned fully on, +12v gate to source, there is very little voltage drop across the mosfet & it behaves like a switch.
When the gate is shorted to the source terminal, the mosfet stops conducting & no current flows.
The only way current can flow when the mosfet is turned off is through the internal zener diode.
A mosfet can be used in the reverse direction as well as in the forward direction.
The internal zener diodes do not prevent a mosfet from being used back to front, since when the gate is high with repsect to the source,
intead of having a 0.6 volt drop you get 10mV or something insignificant, so you can still use it as a switch in the other direction.

No current is allowed to flow through any of the mosfet body diodes in this circuit.
The mosfets are turned hard on, immediately when the diodes become forward biased, thus eliminating any diodes in the high current path.

A number of 12 volt zener diodes have been placed on the base of the push pull circuit, this is to further regulate the 12 volt supply voltages.
The mosfet gate drive supply voltages can be clamped using zener diodes, transistors or 10 watt resistors.

Download Images & Schematics  - http://www.mediafire.com/?dls4s0whqt1ka -

- http://universallyaware.ning.com/photo/no-schottky-diodes-solid-state-mosfet-switching-circuit-6-battery -

[broli]

This looks a bit daunting for anyone to jump in and build it, perhaps if you designed a pcb around it and actually show it in operation more people would like to jump in. You can even sell the pcb's for some monetary gain.

[Qwert]

I think Broli hit the essence. Despite my pretty long presence at this forum, I still feel "green" in electronics fields. Can someone estimate at least an approximate price of such circuit? I guess, I'm determined to build such (at least experimental) system.

[BediniBattery]

The majority of the circuit has been tested practically for functionality, so I am confident that this circuit will function properly without any diodes.

There will be a considerable amount of wiring up to do, not just the high current multicore copper cable but also the gate & source connections, however this enables the power mosfets to be positioned in a favourable place with respect of minimising all circuit resistance.

The numerous 12 volt isolated power supplies will be on one board with the switching circuit on another board.
The power supplies are created using a single mosfet switching circuit & a ferrite toroid with multiple low current secondaries.
12 turns on the primary & secondary is sufficient.
The frequency used should be over 20Khz with pulse width adjustment.
Iron dust cores require more turns but they can also be used.

A minature step down or any volt switching regulator can hold the power supply input voltage so that the isolated power supply circuit does not use more power than is required. A spare battery can be used to power this circuit.

The secondaries need full wave schottky rectifying & a 2200 uF capacitor at 16 volts.
The secondary dc supplies will be voltage clamped at 12 volts using a power transistor & zener diode.

When one secondary winding is clamped, it has an effect on the other windings, but each one will have a seperate voltage clamp to ensure
that none of the mosfet gates are driven over 15 volts. Many voltage clamps will spread the total power dissipation of about 5 watts.
The amount of current used at 12 volts will be 200ma approx, depending on any additonal loading.

This is a work in progress so if there are any errors or mistakes, I will be correcting them as & when I find a problem.

The expensive components are the power mosfets & the lead acid batteries, the rest of the circuit uses low cost parts.

[Qwert]

Some problems(?) http://pesn.com/2012/03/28/9602066_S_Africa_Company_Discovers_Problems_in_Alpha_Testing_their_Fuel_Free_Generator/

The South African company trying to bring this product to market: while it works fine within 3 weeks, it got problems after 3-4 months. The inventor says it's easy to fix, but it needs further tests.