Medium Voltage AC Drives

NC HVVF series medium voltage AC Drive is a voltage source inverter based on IGBT and cell series multilevel PWM technology.

Nancal HVVF adopts vector control and combines PWM technology to realize variable frequency speed control of medium voltage motor.

It is used to satisfy the process automation, reducing energy consumption and protecting environment.

NC HVVF can achieve output voltage up to 18kV with perfect sinusoidal wave form by multilevel PWM. It also can directly drive almost all kind of medium voltage motors without step up transformer.

  • General
  • Specifications
  • Applications
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Capacity 220kW-15MW 7MW-65MW
Cooling system Air cooling Water cooling
Voltage 2.3kV,3.3kV, 4.16kV,6kV, 6.6kV, 10kV, 11kV, 13.8kV, 18kV
Input frequency   50hz/60hz +/- 10%
Output frequency 0-180Hz
Load type Synchronous motors (including permanent magnet motors), Asynchronous motors

Low Harmonic 
High Power factor 
High Efficiency 

Sinusoidal input
Nancal HVVF use multi pulse diode rectifier in input side, with phase shifting transformer, typically from 18 pulse to 54 pulse. It complies with the strictest voltage and current harmonic distortion requirements such as IEEE519-1992. No extra harmonic filter required.
Diode rectifier and multiple pulse input guarantee the input power factor over 0.95. No extra power factor correction equipment required.
Motor friendly output
The output of the NC HVVF adopts multi-level PWM technology to achieve sinusoidal wave with very low du/dt.
This will not damage the insulation of the cable and motor, also will not cause additional heating and torque pulsation on motor.
 *No motor derating
 *No limit of output cable length, can be applied to special applications like submersible pumps
 *No motor heating problems
 *No motor insulation problems
 *Low torque pulsation
 *Low common mode voltage
High Performance Vector Control
Control Mode Vector control with/without speed sensor, V/F control
Speed Range 1000:1 (with speed sensor) /100:1 (without speed sensor)
Torque Response <3ms
Speed Accuracy <0.02% rated speed (with speed sensor)
<0.5% rated speed(without speed sensor)
Core technology
Enhanced Braking Technology  Compared with the traditional drive system, typical deceleration time of motor could be reduced by 30%.
ProCon with LVRT (patented) Ensure the continuous operating of NC HVVF under line fluctuations caused by thunder, storm, etc.
Including kinetic energy buffering LVRT (Low voltage ride through), Spinning load pick up and intelligent torque limit of quadratic load etc.
Synchronous Transfer Can transfer motor from drive to grid (up transfer) or from grid to drive (down transfer) with very stable motor current during the transition.
Cell Bypass with Neutral Point Shift Technology Compared with traditional power cell bypass technology, NC HVVF can ensure maximum output voltage after cell bypass.
VSV -- Integrated Motor Drive and SVG Technology (Patented) No extra SVG required for system which need reactive compensation when motor is idle.

System Configurations
Phase shifting transformer Dry type transformer and oil immersed transformer available.
Power cell
IGBT based voltage source inverter with three phase input, single phase output.
The power cells in one drive has the same mechanic and electric performance and are interchangeable.
Air cooling and water cooling type

Control system The drive control system is composed of DSP board, HMI and PLC.
DSP board: consist of 32-bit high speed digital processor (DSP) & FPGA.
DSP realize related algorithm associated with vector control, FPGA realize multi-level PWM control.
HMI 7-inch (10,12,15-inch optional) color touch screen, 
user friendly HMI. (English and other languages) 
Parameters setting, fault log, event log storage, etc.
PC Software Powerful PC monitoring software
 *Graphical user interface, which display real time data and waveforms
 *Debugging without oscilloscope
 *Fault diagnostic and historic logs
 *Remote access



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