Example applications Chopper Inverter o Also known as inverter thyristors o ON

Example applications chopper inverter o also known as

This preview shows page 8 - 12 out of 15 pages.

Example applications : Chopper & Inverter o Also known as inverter thyristors. o ON-state voltage typically 1.7V for 1800V device. o Example Application : Variable frequency converter (thyristor motor control) Gate-Turn-Off Thyristors (GTO) o Can be turn-OFF by a negative gate signal . o Turn-ON by applying short positive pulse and turn- OFF by a short negative pulse to its gate. o Higher ON-state voltage than normal SCR o ON-state voltage typically 3.4V or 1200V device. o Example Application : Variable speed motor drives, High power inverters GTO thyristor valve at HVDC power station
Image of page 8
25/8/2010 9 Bidirectional Triode Thyristors (TRIAC) o Equivalent to 2 SCR joined in inverse parallel (paralleled but with the polarity reversed) and with their gates connected together. o This results in a bidirectional electronic switch which can conduct current in either direction when it is triggered (turned on). o It can be triggered by either a positive or a negative voltage being applied to its gate electrode o Application : Household power application - light dimmers, speed controls for electric fans Reverse-Conducting Thyristors o Anti-parallel diode connected across SCR on the same silicon chip. o RCT also called Asymmetrical Thyristor (ASCR). o Limited application : Normally in chopper (battery charger) & inverter, AC motor speed & torque controller (inductive loads )
Image of page 9
25/8/2010 10 Static Induction Thyristors o Turned-ON by applying positive gate voltage. o Turned-OFF by applying negative gate voltage. o Low ON-state resistance & low voltage drop. o Very fast switching speeds – Sub micro-second switching time (1 to 6 μ sec) o The rating can go up to 2500V / 500A. o Application : High frequency changers & inverters Light-Activated Silicon-Controlled Rectifiers o Turned-on by direct light radiation on silicon wafer. o Gate structure is sensitive for triggering from practical light sources. o Rating could be has high as 4KV / 1500A. Light-triggered thyristor (LTT) valve used in HVDC power transmission
Image of page 10
25/8/2010 11 FET Controlled Thyristors (FET-CTH) o Combines a MOSFET & a thyristor in parallel as shown. o High switching speeds o Turned ON like conventional thyristors.
Image of page 11
Image of page 12

You've reached the end of your free preview.

Want to read all 15 pages?

  • Spring '17
  • Ilham sentosa
  • Alternating Current, Rectifier, High-voltage direct current, Dimmer, thyristors

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture