Galvanic Isolation

Electromagnetic Isolation of individual PV string provides numerous benefits to both stand-alone PV Systems and DC-coupled Solar + Storage systems 

Alencon's SPOT galvanically isolates the PV strings from one another and from the DC bus. Thus, any faults that occur in the PV such as lightning strikes, ground faults or arc faults will be confined only to one string and will not affect any other devices attached to the DC bus. In traditional PV systems, this includes the central inverter. In combined solar + storage systems, this can also includes batteries.

Galvanic isolation is a unique feature of Alencon’s SPOT and it is not available from other utility scale DC-DC optimizers on the market today. This feature is critical in such a system because it allows for the protection of very expensive battery related power electronics from any harmful faults that occur in the PV array such as lightening strikes, arc or ground faults.

The benefits of the electromagnetic isolation provided by the SPOT-ES can be summarized as follows:

1. Robustness:
The SPOT galvanically isolates the PV strings from one another and from the DC bus. Thus, any faults that occur in the PV array such as lightning strikes, ground leaks or arc faults will be confined only to one string and will not affect the inverter, battery or other PV strings. 

2. Fail-safe
In the unlikely event of an electronic component failure (short of open), the SPOT safely disconnects the failed input channel from the rest of the system.

3. Versatility
The SPOT’s galvanic isolation of each input channel allows complete independence of the grounding scheme of input channels and the output to the DC bus. Each PV string can have negative, positive or floating grounding while the output can be independently grounded in the middle, negative or positive terminals.

4. Wide control range
The SPOT can be configured to map any input voltage regulation range to any output voltage range. For example a 1500 V PV string can be connected into a 600 volt DC bus. On the other hand, lower voltage PV can be connected to a higher voltage DC bus. This unique functionality makes the SPOY and ideal solution when you need to replace a failed inverter or for use in a DC-coupled Solar + Storage system.

5. Interconnect Simplicity
The SPOT is very simple to connect into either in existing PV system as a retrofit or into DC-coupled Sola r + Storage system. The +/- PV cables plug directly into the input connectors of the SPOT and the DC bus cables plug directly into the SPOTs output connectors. With the SPOT, there is no need to split the string in halves or use any other so-called “stretch” techniques.

6. Failure Pinpointing
In the case of a PV string fault such as a ground leak of arc fault, the SPOT will indicate exactly which PV string is in a fault state as well as the severity of the fault.

Harnessing the Power of SiC

The SPOT family of products is built on Silicon Carbide (SiC) metal–oxide-semiconductor field-effect transistor (MOSFET) technology. Alencon is a pioneer in the application and implementation of SiC MOSFET technology. The SPOT is able to take advantage of the unique properties and power density of SiC, namely high power, high voltage and high speed. This combination of characteristics allows Alencon to offer a high power, high frequency DC-DC converter in a small package. The traditional silicon semiconductors used by other PV power electronics manufacturers cannot deliver all three of these features and their resultant benefits. As a result, Alencon is able to deliver a uniquely high power and high efficiency DC-DC optimizer in which the input is electromagnetically isolated (galvanically isolated) from the output. This combination of unique power electronics is not available from any other PV DC-DC optimizer on the market today.