Solar panels currently on the market show peaks in the power delivered to the load devices as the load voltages are varied. Thus, in order to deliver maximum power to the load device, the voltage rating of the load device must match the maximum power point (MPP) voltage of the solar panel. This is very difficult to achieve in practice because the voltage rating of the load device and MPP voltage are determined by entirely different and independent factors.Â
We are working on a universal panel (U-Panel) that indirectly interconnects the solar cells through a patented X1 power extraction circuit. The output power of these U-Panels does not show a peak as a function of the voltage. Instead, the power versus voltage curve is flat for almost all loads. In practical terms, this means a given U-Panel can run many different types of devices, irrespective of their voltage ratings.
For example, a single U-Panel can charge 12 V, 18 V, 24 V and 48 V batteries. The flat power versus voltage curve of the U-Panels also means that the U-Panel can deliver much more power to the load than is possible with a conventional panel of the same size. As a result of this increased power and economies of scale, the cost per Watt of solar power can be substantially decreased.
Additional advantages of these U-Panels include the following:
- Bypass diodes can be eliminated because individual damaged or broken cells do not affect the ability of remaining cells to supply power;
- Loss of power from shadows is dramatically reduced;
- The need for maximum power point tracking (MPPT) devices is reduced because there are no peaks to follow; and
- The need for extensive testing of solar cells at the time of panel manufacture is eliminated, bringing down the cost.
The cells within a unit are connected in series, parallel or a combination of these. Each of the cells is connected to the X1 circuit separately. The X1 unit provides the output terminals of the panel through which the load may be connected.
U-Panels have the potential of a reduced cost per Watt for solar power due to economies of scale. A given U-Panel can be used for many different applications regardless of the voltage requirements. Other cost-reduction factors include the near elimination of extensive cell testing during manufacture, elimination of bypass diodes, reduced need for MPPT and elimination of DC-DC converters.
U-Panels also provide for more robust solar power by enabling the panel to produce power even if one or more of the cells are damaged or in shadow.
Another very important advantage of U-Panels is that a much smaller panel can be used to satisfy most loads. In case the load is a battery, U-Panels provide for much faster charging of the battery due to the perfect match between the battery voltage and the voltage provided by the U-Panel.
For more information about the technology behind universal solar panels, click here.
Waseem Roshen is founder of SS Power Technology in Columbus, Ohio. He can be reached by email at firstname.lastname@example.org.