The BC function is useful for controlling the DC-bus
break. The DC-bus break is required when a motor is
driven, not only in the motoring mode, but also in the
generating mode. The BC function generates the DC-bus
break control signal, based on the actual DC-bus voltage.
The BC function can operate in the following switching modes:
ON/OFF Mode
In this mode, the BC function turns the control signal on when the DC-bus voltage exceeds the
u_dc_bus_ON threshold, and turns the control signal off when the DC-bus voltage falls behind the
u_dc_bus_OFF threshold.
PWM Mode
In this mode, the BC function switches softly using a PWM signal. The u_dc_bus_ON and
u_dc_bus_OFF thresholds define a ramp. When the DC-bus voltage is lower then
u_dc_bus_OFF, the control signal is turned off. Between the u_dc_bus_OFF and u_dc_bus_ON
thresholds, a PWM signal with duty-cycle linearly increasing from 0% to 100% is generated.
Above the u_dc_bus_ON threshold, the control signal is turned on.
For full description refer to AN2845.