10
AVR430
8124C-AVR-10/08
4.3 Shunts
The board is shipped with a common shunt resistor (ShCom - R62) of 0,050 ohm and
the four phase shunt resistors are zero ohm resistors, shown in Figure 4-3. This
allows for measurement of the total current going to ground via all half bridges.
Figure 4-3.
Shunt resistor network.
If current measurements of separate phases are required, the common shunt should
be changed to a zero ohm resistor and the zero ohm resistors on each phase (ShU -
R27, ShV - R38, ShW - R49 and ShX - R64) should be replaced with appropriate
shunt resistors.
4.3.1 Shunt feedback filters
The voltages over the shunt resistors (ShCom/ShU/V/W/X) are fed to a filter/damping
block, ShU as shown in Figure 4-4. The board is shipped with a filter that consists of a
10k ohm resistor in series with a 10nF capacitor, resulting in a low pass filter with a
1,6kHz cutoff frequency. The signal from the filters (ShCom’/ShU’/V’/W’/X’) are
available on the device board interface.
Figure 4-4.
Filter/damping block for shunt feedback.
