Where (V_GK) is gate-cathode voltage and (L_G) is gate inductance. DFT Pro models non-linear components using harmonic Norton equivalents. Our model parameters:
The model treats the GCT as a time-varying resistance: (R_on = 0.001\ \Omega), (R_off = 1\ M\Omega). 3.1 AC Side Harmonics (Without Filtering) DFT Pro computed the following characteristic harmonics for a 12-pulse converter (p=12): dft pro gct
[ \fracdi_Gdt = -\fracV_GKL_G ]
| Harmonic Order | Magnitude (% of fundamental) | Phase (deg) | |----------------|------------------------------|-------------| | 11th | 8.2% | -142 | | 13th | 6.9% | +158 | | 23rd | 3.1% | -88 | | 25th | 2.5% | +94 | Where (V_GK) is gate-cathode voltage and (L_G) is
Non-characteristic harmonics (e.g., 3rd, 5th) appeared only when firing angle asymmetry > 2%. Using DFT Pro's frequency sweep (1 kHz to 10 MHz), the impedance peak at (f_res \approx 3.2\ \textMHz) revealed a voltage overshoot factor: (R_off = 1\ M\Omega).