Rockwell Automation 7000A PowerFlex Medium Voltage AC Drive (A Frame) - ForGe Control - Manual (Page 13)

Rockwell Automation Publication 7000A-UM200C-EN-P - June 2014 13
Chapter
1
Overview of Drive
Introduction The PowerFlex 7000 is a general purpose, stand-alone, medium voltage drive that
controls speed, torque, direction, starting and stopping of standard asynchronous
or synchronous AC motors. It works on numerous standard and specialty
applications such as fans, pumps, compressors, mixers, conveyors, kilns, fan-
pumps, and test stands in industries such as petrochemical, cement, mining and
metals, forest products, power generation, and water/waste water.
The PowerFlex 7000 meets most common standards from the National Electrical
Code (NEC), International Electrotechnical Commission (IEC), National
Electrical Manufacturers Association (NEMA), Underwriters Laboratories
(UL), and Canadian Standards Association (CSA). It is available with the world’s
most common supply voltages at medium voltage, from 2400...6600V.
The design focus is on high reliability, ease of use, and lower total cost of
ownership.
Topology The PowerFlex 7000 utilizes a Pulse Width Modulated (PWM) – Current
Source Inverter (CSI) topology. This topology offers a simple, reliable, cost-
effective power structure that is easy to apply to a wide voltage and power range.
The power semiconductor switches used are easy-to-series for any medium
voltage level. Semi-conductor fuses are not required for the power structure due
to the current limiting DC link inductor.
With 6500V PIV rated power semiconductor devices, the number of inverter
components is kept to a minimum. For example, only six inverter switching
devices are required at 2400V, 12 at 3300...4160V, and 18 at 6600V.
The PowerFlex 7000 has the additional benefit of inherent regenerative braking
for applications where the load is overhauling the motor, or where high inertia
loads need to be slowed down quickly. Symmetrical Gate Commutated
Thyristors (SGCTs) are used for machine converter switches and line converter
switches.
The PowerFlex 7000 provides a selectable option for enhanced torque control
capabilities and increased dynamic control performance. This High Performance
Torque Control (HPTC) feature delivers 100% torque at zero speed and
provides torque control through zero speed with smooth direction transition.