INVERTER OVER-CURRENT LIMIT OPERATION

1
INVERTER OVER-CURRENT LIMIT OPERATION

• Output voltage reduction
• Output current below protection devices tripping
  threshold
• Output current is not enough to perform direct
• on-line induction motor start-up
• Inverter shut down

2
CURRENT PUMPING DEVICE (CPD)
3
BENEFITS OF CPD INSERTION
Polypropylene Capacitors
Short Circuit
Motor Start-Up
4
SUPERCAPACITORS (EDLCs) FOR CPD REALIZATION

• High currents for extended periods of time
• Extremely small dimensions
• Capacitance of thousands Farads in very small
  devices
• Costs reduction in the next years

5
EDLCs DO NOT SEEM SUITED FOR CPD REALIZATION

• High ESR values (hundreds of m? up to 100 ?)
• Small rated voltage values (about 2.3V)
• Capacitance is strongly dependent on frequency

6
EDLCs DO NOT SEEM SUITED FOR CPD REALIZATION

• ESR reduction is desirable
• It is difficult to develop high voltage
  supercapacitors
• There is not a big market in AC applications
  nowadays the efforts of the research are only
  oriented towards DC applications