Self-oscillating teslacoil

(Extended to full-bridge operation)

Abstract

Adding a second half-bridge to the existing self-resonant tesla coil improves the performance noticeably.
The increased primary voltage required more primary turns and less primary capacitance to keep the current low. Now the coil runs with almost the same current but with twice the voltage than in half-bridge configuration, doubling the power.
There will be more information (schematics, ...) soon.

Assembly

Primary capacitor

The primary capacitor has been changed to six WIMA FKP-1 capacitors with 10 nF / 1600 V DC each. 3 parallel strings of 2 capacitors in series give a total capacitance of 15 nF at 3200 V DC.

Primary coil

The primary coil is made of 10 turns PVC isolated stranded wire, 4 mm (0.157") in diameter. It is wound on a PVC former that is 16 cm (6.3") in diameter. The primary coil is elevated 6.5 cm (2.56") above the secondary base.

Secondary coil

The secondary is wound on a PVC pipe with a diameter of 10 cm (4") and a length of 45 cm (18"). There are 1140 turns of 0.3 mm (awg 28) enameled copper wire. The calculated resonance frequency is approx. 350 KHz, but the operation frequency is set to around 300 KHz which seems to match the secondary resonance frequency pretty good.
A breakout point is added on the top of the coil to guide the discharges upwards.

Operation

Finally, there are some pictures and videos of the coil operating. Horizontal: 1 µS per division
CH1: Output of one half bridge section, 50 V / div.
CH2: Gate drive of the lower IGBT of that half bridge section, 20 V / div.
CH4: Primary tank current, 50 A / div.

Coil and discharge pictures

Figure 1.4: Discharges	Figure 1.5: Discharges
Figure 1.6: Discharges	Figure 1.7: Discharges

Discharge videos

Figure 1.9: Discharge video

Figure 1.10: Discharge video (ambient light on) Watch this video on YouTube