lisäpysäytysvastus

Lisäpysäytysvastus, often translated as "additional braking resistor" or "dynamic braking resistor," is a component used in electrical drive systems to dissipate excess energy generated during deceleration. When an electric motor slows down, it can act as a generator, feeding power back into the drive system. In systems without regenerative braking capabilities, or when regenerative braking is insufficient or not desired, this excess energy needs to be safely discharged to prevent overvoltage in the DC bus of the motor drive.

The lisäpysäytysvastus is typically a power resistor connected in parallel with the DC bus. During braking, when the voltage on the DC bus rises above a certain threshold, a control unit in the motor drive activates a semiconductor switch, such as a transistor or an IGBT, which connects the resistor to the DC bus. The electrical energy generated by the motor is then converted into heat within the resistor, thereby limiting the DC bus voltage and protecting the drive components.

These resistors are crucial for applications involving frequent braking, heavy loads, or rapid deceleration, such as in elevators, cranes, industrial machinery, and electric vehicles. The size and resistance value of the lisäpysäytysvastus are determined by factors like the motor's power, the required braking torque, and the duty cycle of the application. Proper sizing ensures effective energy dissipation without overheating the resistor or causing performance issues.