Silicon carbide drive is `world`s first`

Siemens has become the first drive manufacturer to use silicon carbide semiconductors in a commercial product. For years, SiC has been touted as the next generation of power semiconductor, offering advantages over conventional silicon devices such as ruggedness and the ability to operate at high voltages and temperatures.

Siemens is using SiC devices in the filter section of a 690V power module for its Sinamics G120 drives covering ratings from 7.5-55kW. The SiC devices operate at high pulse frequencies, allowing a small sinusoidal filter to be used, and resulting in a compact, efficient and quiet power module that is easy to integrate.

The G120 inverter can operate in a line-commutated regenerative mode that feeds excess power back into the power supply during braking. It achieves this using a bidirectional input rectifier, and does not need a brake chopper or braking resistor. Siemens also claims that the drive causes less system perturbation than a conventional inverter.

A module is available to turn the inverter into a "safety integrated drive", offering safety functions to Category 3, SIL2, without needing a speed sensor. The safety functions can be controlled via safe digital inputs or Profisafe.

An optional LC filter ensures a clean sinusoidal output and allows the use of unshielded cables up to 300m long. The use of the SiC technology means that an inverter with the filter is smaller than a standard inverter with the same output.

• Volvo is investing about £150,000 in a Swedish company, TransSiC, which is developing silicon carbide devices that could be used in hybrid electric vehicle drives. These drives could be smaller, lighter and cheaper than drives based on conventional semiconductors, and may not need to be cooled.