MMP SA-2550A
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DESIGN, MANUFACTURING & DISTRIBUTION - MOTION CONTROL EQUIPMENT
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Regenerative braking with the SA-2550A
Regeneration and Shunt Regulators
Use of a shunt regulator is necessary in systems where motor deceleration or a downward motion of the motor load will cause the
system’s mechanical energy to be regenerated via the drive back onto the power supply.
I
Ve
No Regen
II
Torque -
Ve
Regen
III
Torque -
Velocity -
No Regen
IV
Velocity -
Regen
Figure 3. Four Quadrant Operation – Regeneration occurs when Torque and Velocity are opposite.
This regenerated energy can charge the power supply capacitors to levels above that of the drive over-voltage shutdown level. If the
power supply capacitance is unable to handle this excess energy, or if it is impractical to supply enough capacitance, then an external
shunt regulator must be used to dissipate the regenerated energy. Shunt regulators are essentially a resistor placed in parallel with
the DC bus. The shunt regulator will "turn-on" at a certain voltage level (set below the drive over-voltage shutdown level) and
discharge the regenerated electric energy in the form of heat.
The voltage rise on the power supply capacitors without a shunt regulator, can be calculated according to a simple energy balance
equation. The amount of energy transferred to the power supply can be determined through:
𝐸
𝑖
= 𝐸
𝑓
Where
𝐸
𝑖
=
Initial Energy
𝐸
𝑓
=
Final Energy
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