Delta REG2000 Series, Руководство пользователя

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01 Product Overview | REG2000
1-3
1-5 Operating Principle
In a variable-frequency drive system, the motor is in a power generating state due to the high inertia in
a drive system such as centrifuges and washing machines, or applications requiring fast braking such as
machine tool spindles. In other words, because the rotor is rotated by external forces, the actual motor
speed exceeds the drive-controlled synchronous speed, quickly feeding the energy generated by the motor
back to the DC BUS. This results in a rapid rise in the DC BUS voltage and endangers the drive. This
excess energy must be quickly consumed to keep the DC BUS voltage within a safe range; otherwise, the
drive will either malfunction or enter over-voltage protection mode.
The traditional method is to convert the excess energy into heat with a brake resistor. This method
has the advantages of simpler wiring and lower total cost, but has the disadvantages of a large brake
resistor, requiring additional cooling devices, a limited braking capability, and inefficient energy use. On the
other hand, the Power Regenerative Unit (REG2000) converts the power generated by the motor into
electric energy, and then returns it to the electrical grid for other electrical applications, thereby conserving
energy. Installing the Power Regenerative Unit can increase the motor's braking capability.
When you set the DC BUS voltage activation level (Pr.01-08), the Power Regenerative Unit
(REG2000) determines the motor drive’s DC BUS voltage regenerative trigger point to satisfy the
regenerative demands in various industrial applications. When the DC BUS voltage is higher than the
voltage activation level, the Power Regenerative Unit (REG2000) starts regenerating power. The
capacitance clamping voltage is set as the activation level and the excess energy generated by the motor
is converted to three-phase AC current to regenerate the mains power (AC).
The Power Regenerative Unit (REG2000) stops the power regeneration immediately and continues to
operate (RUN) when either of the following conditions occurs. The DC BUS voltage triggers the DC-side
voltage activation level until the motor brakes for the next time.
(1) When the DC BUS voltage is lower than the activation voltage level (default value = 10 V)
or
(2) When the output current (A
AC
) of the Power Regenerative Unit (REG2000) is 10% lower than the rated
output current for 1 second.