With the introduction of a fully integrated, regenerative AC drive, in a 7.5hp to 2,600hp range, ABB again extends the array of complete motor-control solutions provided through the company’s ACS800 product family. Regenerative drives, also known as four-quadrant drives, incorporate an active supply unit rather than the passive diode supply used in conventional drives. They also have a built-in LCL filter to eliminate high-frequency harmonics.

Full, constant energy utilization; superior low harmonic solution

“Regenerative drives offer two significant advantages: they can recover energy from a process and feed it back into the network, and they help to maintain power-supply quality, thanks to their superior harmonic performance,” notes Mike Vallier, product line manager for the ACS800 family at ABB, low-voltage drives. “ABB’s regenerative AC drives harmonic-distortion levels are lower than conventional 18-pulse drive products. They meet rigorous harmonic standards right out of the box.”

The new drives from ABB are the first fully integrated units available for the power range up to 2,600hp. They feature a line-side IGBT supply that makes it easy to return power to the line, and an active filter keeps the supply a clean sinusoidal wave form (conventional non-regenerative AC drives have a passive diode supply that cannot return energy to the supply line). This ability to return energy to the supply line saves energy and eliminates the need for a braking chopper, resistor hardware and extra wiring.

Regenerative AC drives for this power range previously have consisted of a number of interconnected power blocks, according to Vallier. “With this innovative single-unit design, selection, ordering and delivery logistics all become much more straightforward,” he said. The compact and integrated design is also easier to install and commission. Each drive is thoroughly factory tested as a unit and is guaranteed to perform according to specification.

Everything inside

In keeping with ABB’s industry-leading “everything inside” product philosophy and design, an extensive range of features and accessories are housed within the drives. The low-harmonic LCL line filter, flexible I/O and control panel are supplied as standard. All the regenerative drives are delivered standard with ABB’s start-up assistant, which provides menu-driven help that makes setting parameters intuitive and easy. Optional accessories include EMC filters and extension modules for additional I/O and field bus (communication) adapters. Model number ACS800-U11, for wall-mount drives from 7.5hp to 125hp, are designed for operating voltages of 208VAC to 240VAC and 380VAC to 500VAC. The protection class of UL type 1 (IP21) is standard.

Model number ACS800-17 units are designed for operating voltages of 380VAC to 500VAC and 525VAC to 690VAC, and available from 150hp to 2,600hp with protection class of UL type 1 and optional type 12 (IP54).

Full energy utilization and protection of power quality

Typical applications for regenerative AC drives include industrial centrifuges, test stands for vehicle engines and transmission, sheet metal presses, cranes and lifting equipment, conveyors, escalators, and even ski lifts and cable cars. The energy recovery feature of regenerative AC drives makes significant energy savings possible in applications such as sugar centrifuges. In each centrifuge cycle, the drum needs to be decelerated and brought to a stop as quickly as possible, once the process is complete. “This braking phase releases a considerable amount of energy, which, instead of being wasted as heat, can be fed back into the network,” notes Vallier. “And that’s true for any process that has residual momentum – whether a converting or papermaking mill utilizing rollers, or a ski lift with riders traversing both up and down mountainsides.”