4 Brake Chopper Overview
4.1 Work Principle
Brake chopper is used to consume the electrical energy returned from the exter-
nal motor to frequency converter during braking, and limit the DC-bus voltage of
frequency converter into a rational range to improve the braking performance
and finally stop motor quickly. Before the brake chopper is normally running, the
start voltage for braking should be properly set according to the selected fre-
quency converter and its load condition, while the stop voltage for braking can
be set by parameter H6.03.
When brake chopper is normally running, its control circuit detects the DC-bus
voltage in real time. If the bus voltage reaches the pre-set start voltage which
can be set by parameter H6.01, brake chopper will start braking during which
the electrical energy returned from the motor is consumed by the external brak-
ing resistor, and stop braking until the bus voltage reduces to the stop voltage.
The braking duty cycle can be adjusted by parameter H6.02. The higher the duty
cycle is, the better the braking performance will be. Braking duty cycle should
be properly set according to the actual load condition. For example, if the brake
resistor overheats, the duty cycle should be appropriately reduced with the
premise that the braking performance is satisfied.
Fig. 4-1: Work principle
Bosch Rexroth AG
Brake Chopper Overview
Brake Chopper
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DOK-RCON03-EFC*BRAKE**-IT01-EN-P
