DC:DC Converters: The Bridge to the New Hydrogen Economy

Why High Power, High Voltage DC:DC Converters are Critical to Achieving the Promise of Clean Hydrogen

As trillions of dollars are plowed into our transition to clean energy, hydrogen powered fuel cells stand poised to represent the third and balancing leg of the renewable energy stool, with solar and battery energy storage comprising the first two. Like solar and batteries, hydrogen fuel cells are a DC energy source. However, to take their rightful place in the pantheon of our clean energy future, hydrogen fuel cells need, well, a boost. A boost in voltage that is. That’s where DC:DC converters, like the ones made by Alencon, come into play.

A single fuel cell produces less than 1 V, which is insufficient for most applications. Therefore, individual fuel cells are typically combined in series into a fuel cell stack. A fuel cell stack’s voltage ranges anywhere from 100 to 500 volts - far lower voltage than we are accustomed to for modern day solar and battery energy systems operating at voltages of 1000 to 1500 volts. Alencon’s galvanically isolated DC:DC converters provide a significant boost to the fuel cell’s voltage, allowing them to operate in the same range as more typically available and cost effective higher voltage equipment. Alencon’s isolated DC:DC converters are particularly helpful in this regard because they use a specialist, high-frequency silicon carbide transistors and transformers to map the nominal voltage of the fuel cell into the nominal voltage of the DC bus to which it is connected. Once the DC:DC converter brings those two different voltage levels onto the same operating plane, the software controls of the device take over to manage any dynamic changes on the fuel cell stack to stabilize the DC bus voltage to which.

The help the isolated DC:DC converter gives the hydrogen fuel cell extends beyond just the voltage boost. The isolated DC:DC converter also shields the fuel cell from any potential harmful electrical faults in the broader system to which it is connected. This creates the opportunity for leakage to ground between the cells. Therefore, much like batteries, it is imperative that fuel cells remain floating, such that two leakages to ground are needed to cause a ground fault. By isolating the fuel cell from the rest of the system to which it is connected, these faults can be more easily detected without interference from other parts of the system. As fuel cells are naturally coupled with other DC elements like solar and batteries on a common DC bus, the need to isolate their grounding becomes all the more important.

The discussion above refers to the process of turning hydrogen into electricity. But what about actually creating hydrogen? Hydrogen can be “manufactured” in precisely the opposite manner as is used to make electricity from it, a process known as electrolysis. Electrolysis is the process of using electricity to split water into hydrogen and oxygen. This reaction takes place in a unit called an electrolyzer. Today, much of hydrogen produced in the world is created with energy from fossil fuels.

According the GreenBiz Group, today, only 1% of world’s hydrogen supply is “green” meaning it is created from renewable energy like solar. DC:DC converters offer great promise for efficiently creating green hydrogen from solar by mapping the relatively high DC voltage at which large scale solar plants operate to the significantly lower voltage required by electrolyzers to create green hydrogen, all without a costly conversion to AC along the way.

As such, look for high power, high voltage DC:DC converters like the ones Alencon makes right here in the United States to play a critical role in our transition to a clean, hydrogen economy.