AN1506 - APPLICATION NOTE

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Figure 7. Schematic of the 3-phase full bridge inverter

In our case study with a figure of 4% a (quasi-constant) commutation frequency of 24.5kHz has been

observed. Figure 8 shows the experimental traces of the three sinusoidal currents feeding the motor. The

fundamental inverter frequency is 0.5Hz according to the need of the low speed on the wheel shaft.

Figure 8. Traces of the motor phase currents while the drive is operating at a fundamental

5.1. Power Losses Estimation.

The device power losses are related to the switching behavior, and the on-state condition. In a generic

th switching cycle the energy losses at turn-on, turn-off, and on-state condition are expressed

respectively by:

•

•

•

•

Vd (+24V)

T

T

D

D

T

D

T

D

T

D

T

D

PHASE A

PHASE B

PHASE C

PM MOTOR

ABSOLUTE

ENCODER