The Secret to More Efficient Solar Panels

The solar power market has grown rapidly since 2015–and solar’s deployment is managing to outstrip many traditional power sources. Even as the market grows and solar power installations become more commonplace, consumers still await lower power prices.

Efficiency is critical to solar panel performance and the monetary benefits solar panels can provide. While success has been achieved with photovoltaic (PV) conversion and moving power into the grid, there are system-level improvements in efficiency at the PV panel plus micro-inverter levels necessary to see lower prices trickle down to the consumer.

 

Figure 1. Solar power has become an accepted alternative to more traditional power sources, but increases in system-level efficiency are needed for consumers to see lower power prices. Image used courtesy of Pixabay

 

Solar Panel Efficiency

Solar panel systems (such as the one illustrated in Figure 2) have two layers of efficiency. The first layer is efficiency related to transforming energy from the sun into electrical current and power conversion. The second layer of efficiency involves moving and converting the photovoltaic photons to electrons as power into the grid for energy harvesting or usage within the dwelling or local energy storage. 

 

Figure 2. Block diagram of the various components within a solar energy system. Image used courtesy of Infineon

 

At the first layer, photovoltaic panels are getting physically larger, and the cells that comprise them are growing in size and improving in efficiency. In addition, it now costs the same to install a 3 m2 panel or a 6 m2 panel. Because installation costs are declining, the residential market is more accepting of larger PV panels, and the use of these panels is gaining significant traction. Furthermore, solar cells are getting more efficient, with a target efficiency of up to 30% and an industry average between 18% and 20%.

 

Figure 3. Micro-inverters convert power to individual photovoltaic panels or multi-panels in solar power systems. Image used courtesy of Infineon

System-level Efficiency

As mentioned earlier, system-level efficiency is the key to lower costs trickling down to consumers. One approach to improving system-level efficiency is during power conversion. There are two general approaches to increasing efficiency: either using an all-inclusive (as illustrated in Figure 3) or implementing a string inverter (see Figure 4), and both are already at 98% to 99% efficiency. However, is it still possible to reduce system costs at this level?

 

Figure 4. Unlike micro inverters, string inverters perform power conversion panels that are series connected and are often upstream of power optimizers. Image used courtesy of Infineon

 

Is GaN the Secret to More Efficient Solar Panels?

A reduced form factor is necessary to reduce system costs on micro-inverters or optimizers. The industry standard is to use Si-based components, but the efficiency optimizations are at a point of diminishing returns, and customers have reached the silicon limit. 

Wide bandgap devices such as Gallium Nitride (GaN) enable designers to exponentially increase system switching frequency and, therefore, reduce the size of the magnetics and lower the system cost. Remember that the magnetic components dictate the size and form factor, and the form factor depends on the switching frequency. 

Therefore, increasing the switching frequency also means decreasing the form factor. This leads to reduced system costs. GaN also supports significantly higher switching frequencies than its Si-based alternatives, making GaN components an obvious solution to achieving higher levels of efficiency at the system level.

 

Benefits of GaN-based Components 

There are several benefits to using GaN-based components (whether for small installations or massive solar farms such as the one shown in Figure 5) when implementing all-inclusive micro inverters or DC-DC optimizers. For example, GaN makes it possible to achieve a smaller form factor and reduce system cost even though GaN components are relatively more expensive. In addition, GaN supports improved performance while lowering costs, thus coming closer to grid parity. Furthermore, it makes it possible to lower $/watt costs at the consumer level.

 

Figure 5. GaN products provide a host of benefits. Image used courtesy of Pixabay

Finally, GaN solutions are a greener, more environmentally responsible approach to energy production.

 

Why Choose Infineon GaN Solutions

Reliability is especially critical in the solar panel market, where solar panel technology requires a guarantee of 25 years (not unlike the warranty for a roof). While smaller, newer companies manufacture GaN components, they have not had time to achieve a proven reputation for long-term reliability.

Infineon products support scalability and cost because its size and experience allow them to scale production volumes to meet evolving customer needs. Bringing down system costs on the microinverters or DC-DC optimizers makes photovoltaic solutions more affordable for the consumer. GaN-based microinverters and optimizers, as opposed to traditional silicon-based solutions, can reduce overall system costs by increasing the switching frequency and reducing the form factor. This, in turn, leads to lower power prices. 

To learn more, visit Infineon’s GaN solar-power solutions website.