BREK Electronics

Solar panels produce direct current electricity, which must go through an inverter that outputs alternating current that can be fed into the grid. String inverters, in contrast with central inverters, are typically small and relatively easy to install, and their faults can be easily detected, isolated, and resolved without the need for skilled technicians. This eliminates costly system downtime and units can also be easily swapped without affecting the rest of the system.

As the size of large commercial and utility scale solar power plants is increasing, so is the need for larger sized string inverters. However, in order to achieve >150 kW using traditional silicon-based circuits, the weight and size increases dramatically, and installation and shipping costs becomes prohibitive. High power silicon technology is limited in efficiency and thermal conductivity, which leads to overheating — a leading cause of failure in electronic components. Therefore, a paradigm shift is needed away from silicon-based circuits to new materials and architectures capable of handling higher power densities.

Silicon Carbide is a promising wide bandgap semiconductor capable of handling very high power with its extremely high switching frequencies - up to 300 kHz and 30x faster than competing IGBTs silicon. Operating at higher switching frequencies is advantageous as it can lead to lower inductor and capacitor size, weight, and cost.

To achieve the potential gains afforded by new silicon carbide components, most inverter manufacturers currently use brute-force replacement of silicon IGBTs with silicon carbide MOSFETs, whereby they are able to achieve some incremental improvement in performance. This is because these drop-in replacements do not change the underlying circuit architecture to take advantage of silicon carbide’s inherent material properties and instead run the silicon carbide chips at 50 kHz, leading to only marginal improvements in power density, efficiency and cost.

Significant improvements can only be achieved when new silicon carbide semiconductors are combined with advances in power circuits and reactive element design. BREK has re-designed the inverter from the ground up using new state-of-the-art Silicon carbide Composite Converter Architectures (SCCA).

Using this approach, BREK Electronics is delivering the world’s first compact, three-phase, 200 kW grid-tied solar string inverter that can be easily installed manually with a two-person lift, forgoing the need for heavy machinery. Two of these units can be made into a single 400 kW unit, with each 200 kW unit being one MPPT zone.

Besides achieving higher efficiencies, the faster switching can be leveraged to reduce the volume and cost of the magnetics components. BERK’s inverters use compact, light-weight planar magnetics instead of heavy, hand wound magnetics, leading to an overall system with significantly higher power density along with smaller size, lower weight, and cost.

BREK understands the market is driven by cost and reliability. To keep costs low, BREK uses 1200 V SiC MOSFETs, the same devices favored by the electric vehicle market. The high demand for these components drives down their price, letting BREK’s inverters benefit from economies of scale from the EV industry. Furthermore, BREK’s boards use planar magnetics and ceramic capacitors, which are readily adaptable to domestic high-speed automated manufacturing.

Assembly in the U.S. also comes with security benefits. Recent cyber-attacks have highlighted vulnerabilities in the U.S. energy infrastructure. In the solar power industry, the U.S. government has banned the use of some Chinese made inverters for fear of hidden ‘back-doors’ that could be exploited for surveillance or disruption. BREK’s approach is to securely manufacture its high-power solar string inverters in the U.S. while taking full advantage of the recently announced IRA subsidies.