Static frequency converter

OPERATING PRINCIPLES, DESIGN AND GENERAL FEATURES OF THE DEVICE

Operating principle

Static frequency converters are used to feed loads that require AC power at a fixed frequency different from what is available from the grid. Using an intermediate DC transformation, the device can deliver that power under the required conditions.

Subsequently, one unit consists of 2 sub-subsystems:

  • Rectifier: converts incoming AC voltage to DC
  • Inverter: converts DC voltage to AC at the output at the required frequency

Batteries can optionally be added to the system so it can be autonomous in the event of a grid failure.

Device design 

The device has excellent dynamic behaviour with IGBT transistors. It’s controlled by a microprocessor that governs the unit in response to different keywords and signals it receives and informs the user of its status.

Control functions:

  • History: last 250 alarms with time and date
  • Automatic control: programmable start up and shut down
  • Diagnostics: visualise and transmit the status of the device
  • Measurements:
  • Vef and Ief of all phases
    • Active, apparent and reactive power
    • Internal system temperatures
    • Output
    • Cos and input and output frequency
    • Test: automatic, local/remote, periodic and programmable
    • Digital settings: parameters adjustable by keyboard
    • Configurable: basic system functions can be defined
    • Tips: using the keyboard

General features of the device

  • High power factor at input: 20.95
  • Digitally synthesised perfect sine wave output
  • High frequency stability and output voltage
  • High performance, simplicity and reliability
  • Excellent behaviour with non-linear unbalanced loads
  • Multiprocessor digital control, PWM modulation
  • Interface using a display, keyboard, LEDs and serial communication
  • Built in galvanic isolation transformer
  • Can optionally operate in parallel with other units
  • Can include an auxiliary power supply form 28 Vdc up to 1000 A

Features

  • Input: Three-phase 220 / 380 / 400 VAC + 15 % – 10% – Frequency 50 / 60 Hz ± 5% – power factor up to 0.9
  • Output: From 5 to 1300 kVA – Frequency 50 / 60 / 400 Hz ± 0.1 % – Single-phase 220 VAC ± 1 % – Three-phase 220 / 380 / 400 VAC ± 1 % – Voltage adjustment ± 5 % Vn – allowable cos 0.6 capacitive / 0.4 inductive – Harmonic greater 3 % – Max distor.THD global linear load < 3 % - non-linear load < 5 % - Dynamic response ± 5 % - Response time 30 ms - Crest factor 3 - Yield 80 - 93 %, depending on power
  • Options: Pb or NiCd batteries – 6 or 12 pulses – Anti-harmonics filter – LBP line stabiliser transformer – 28 VDC / 160 a 1000 A Auxiliary source – Redundant – Operation in parallel with other units – Class 1E Anti-earthquake – Output distribution board – Manoeuvre board– Adaptation to diverse regulations (MIL, UL, …)
  • Design: Self-supporting metal cabinet – IP20 to IP54 Protection – Colour RAL 7032 (standard)

All the features above can be modified on demand.

Data sheet