KIT power supply offers 50-year lifetime

Switching power supplies are ubiquitous, may it be in households, offices or industry. They convert the alternating current supplied into direct current for smartphones, laptops, charging stations of e-cars and logistics and computing centres. However, conventional power supplies usually have to be exchanged after nine years of permanent operation. Digital Power Systems (DPS), a spin-off of Karlsruhe Institute of Technology (KIT), has developed and tested power supplies with a lifetime of 50 years.

Conventional switching power supplies are light and compact, but susceptible to failure due to the electrolyte capacitors they contain. Film capacitors are more long-lived; however, they need up to 10 times more space. DPS Director Michael Heidinger said researchers have now developed a digital control process, by means of which film capacitors can be used on smaller space. “This technology is a game changer wherever reliability is important. These may be computing or logistics centres or flight safety lamps,” Heidinger said.

Joint tests with KIT’s Light Technology Institute revealed that the new power supplies have a lifetime of 50 years at an ambient temperature of 40 degrees. “This is about five times that of established power supplies. So far, no power supply has failed and tests are being continued. “We have not yet reached the limit,” Heidinger said.

The novel digital control process enables the use of film capacitors with a slightly increased space requirement. For control purposes, a microprocessor is integrated in the power supply. It detects disturbing ambient impacts and balances large voltage fluctuations of the film capacitor. As a result, storage capacitors of smaller capacity are sufficient. According to Heidinger, powerful microprocessors made this possible.

The power supply is already used for air safety illumination and is installed in lamps on stacks, wind turbines or radio masts to warn airplanes. Replacing damaged power supplies there can be tedious and costly, as industrial climbers are needed.

Image credit: Marco Wünschmann, Welectron