MMC Calculator
MMC (Multiple Mini Capacitor) are often used in Tesla coil designs for SGTC, DRSST and various others. To satisfy the need for high voltage at moderately high capacities, MMC are a cheap alternative to expensive single capacitors. For bigger Tesla coils, the necessary capacitor values are too high for a single capacitor anyway and a MMC is no longer optional.
The capacitor parameters and the peak current can be extracted from the individual datasheet. The primary peak current is defined by I_{RMS} of the used IGBT.
The capacitors used in the example below are Dawn-cap “DTR6000K0.44” which have amazing parameter for Tesla coil builds. The IGBT’s used are the “SKM-200GB128D”.
Equations
Use SI-Units for the equations.
MMC parameter results:
C_{MMC} = \frac{C * n_{parallel}}{n_{serial}} U_{MMC} = U_{DC} * n_{serial} n_{C} = n_{serial} * n_{parallel}Advanced results
Z_{primary} = \sqrt{\frac{L_{primary}}{f_r}} X_{c} = \frac{1}{2\pi*f_r*C_{primary}} Z_{c} = \sqrt{(ESR*n_{serial})^2+(\frac{X_{c}*n_{serial}}{n_{parallel}})^2}MMC: Necessary/Available parameters
U_{peak} = Z_{c}*I_{peak} I_{RMS} = 0.5*I_{peak}*\sqrt{\frac{t_{on}}{BPS}} {dV/dT} = \frac{2\pi*U_{peak}}{f_{r}} I_{peakMMC} = I_{peak}*n_{parallel}