Rockwell Automation 7000 PowerFlex Medium Voltage Air-Cooled (B Frame) Installation - ForGe Control - Manual (Page 11)

Rockwell Automation Publication 7000-IN007E-EN-P - June 2014 11
Chapter
2
PowerFlex 7000 Overview
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 uses a Pulse Width Modulated (PWM) – Current Source
Inverter (CSI) for the machine side converter as shown in
Figure 6 . This
topology applies to a wide voltage and power range. The power semiconductor
switches used are easy-to-series for any medium voltage level. Semiconductor
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 minimal. For example, only six inverter switching devices are
required at 2400V, 12 at 3300...4160V, and 18 at 6600V.
The PowerFlex 7000 also provides inherent regenerative braking for applications
where the load is overhauling the motor (e.g. downhill conveyors, etc.), or where
high inertia loads (e.g. fans, etc.) are quickly slowed down. The drive uses
Symmetrical Gate Commutated Thyristors (SGCTs) for machine converter
switches, and Silicon-controlled Rectifiers (SCRs) (for 18 Pulse rectifier
configurations) or SGCTs (for Active Front-end [AFE] rectifier configurations)
for the 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.