BLDC Inverter Loss Calculator
This tool models the thermal performance of a 3-phase inverter bridge. It calculates Conduction, Switching, and Diode losses for the 6 switches.
Select Trapezoidal (2-phase conduction) or Sinusoidal (3-phase modulation) to see how the heat load changes.
System Parameters
Drive
V
A
kHz
0-1
Device Specifications
MOSFET
mΩ
ns
ns
nC
ns
V
°C/W
°C
Loss Analysis
LiveTotal Inverter Heat
— W
Est. Inverter Eff: — %
Junction Temp (TJ)
— °C
Enter parameters
Included Loss Models
Conduction (Pcond)
Trap: Ipk² × RDS × (1/3)
Sine: (Ipk / √2)² × RDS × 0.5
Uses Temperature-adjusted RDS(on).Switching (Psw)
0.5 × Vbus × Ipk × (tr + tf) × fsw
Averaged over the active modulation period.Dead Time (Pdt)
VSD × Iavg × tdead × fsw
Body diode conduction during the dead time gap.Reverse Recovery (Prr)
Qrr × Vbus × fsw
Energy lost when body diode turns off.How to Use
Estimate drive thermal performance.
1
Select Mode
Choose Trapezoidal for 6-step BLDC (2 phases active) or Sinusoidal for FOC PMSM (3 phases active).
2
Define System
Enter Bus Voltage, Peak Current, and Frequency. Don’t forget Dead Time if you are pushing high frequencies.
3
Check Heatsink
The Total Inverter Loss dictates your heatsink size. Keep the Junction Temp below 125°C for reliability.