In its most basic form, a thyristor is a solid-state power semiconductor device with four alternating layers of P-type and N-type semiconductor material. A thyristor acts as a bistable switch, conducting (i.e. turning-on) when its gate receives a current pulse. A thyristor continues to conduct as long as it is forward-biased (until the voltage across the device is reversed). Thyristors are synonymous with silicon controlled rectifiers (SCRs).
Thyristor Modules include one or more thyristors and, in some cases, other power semiconductor devices, such as diodes. Thyristor module packages are electrically isolated, and usually include metal base-plates (sometimes copper) and a DCB Alumina substrate (Al2O3 Insulator). Thyristors can cycle an amazing amount of power, with voltage ratings typically between 300 – 2,400 volts and current ratings from 25 – 3,080 amps. Most Thyristor Modules are UL Recognized.
Applications for Thyristor Modules include Bridge Circuits, AC Motor Drives, DC Braking, Battery Chargers, Power Supplies, Large IGBT Front End Circuits, Lighting Control, Heat/Temperature Controls (for large commercial ovens, chemical processes, etc.), and Welders.
Specific attributes which are important in selecting the right Thyristor Module for your application include: Configuration - Single, Dual, AC Switch, Anti-Parallel Pair, Pair Common Anode, Phase Leg (Series Pair), Dual Anti-Parallel Pair, Triple Anti-Parallel Pair, 3-phase Bridge Rectifier + Series Thyristor, and many more configurations available; Voltage Rating (V); Current Rating (A); and Package Type.
Richardson RFPD maintains a robust selection of Thyristor Modules from Mitsubishi, Powerex, and Semikron.