The Vacon NXP DCGuard is a device that maintains the safety and stability of a DC grid system by detecting and cutting off any faulty direct currents (DCs) within 50 microseconds and, thereby, protecting the surrounding equipment by preventing brownouts associated with typical fuse or breaker protections that take up to 100 times longer to trip. Further, it enables connection of two different DC grids with voltage differences, and, more importantly, prevents accidents and injuries.

The semiconductor protection device is based on standard VACON NXP inverter hardware and new software. During a short circuit, the VACON NXP DCGuard disconnects the healthy side from the faulty side before the short circuit affects the healthy side. The fast isolation ensures the healthy side can continue to operate as normal after the short circuit situation. This enables a secure DC grid and is a key enabler for DC networks used in many different applications, such as data centers, commercial buildings, or factories.

Short-circuit handling has been one of the hurdles for wider usage of DC power supplies and distribution in data centers as it is difficult to ensure the required system functionality by using fuses. Therefore, data center owners and operators have not harvested the advantages of using distributed DC power distribution systems. The VACON® NXP DCGuard™ protects their efficient investments and allows them to employ DC power systems safely and with peace of mind.

The design process began with research on DC systems and their existing challenges. We looked at customer issues with existing systems, particularly with long delays for fuse burning and circuit breaker trips. To gauge if systems could respond more quickly, the company conducted an analysis of IGBT and current sensing and developed application parameters to create faster response using traditional VFD hardware, including the need for additional reactance on the DC bus. The final step was testing and certification for certification bodies in order to develop a unique solution for the markets that keeps DC distribution systems active during a fault condition, which previously would have blacked/brown – outed or caused ancillary damage.

It is a new way of approaching system fault currents in DC grids. Unlike a fuse, the VACON NXP DCGuard can easily be reset and restarted once fault conditions have been removed.

This will remove barriers for end users who are reluctant to switch to more efficient DC systems due to concerns over short circuit fault currents. It helps to enable a transition of efficient energy management of multiple power sources by reducing losses associated with AC to DC grid conversion.

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