Schurter, a Switzerland-based provider of electrical components, has developed a new DC filter series – FMER SOL – designed for use with the DC side of PV inverters. The filters are approved up to 1,000 VDC and an ambient temperature up to 75 degrees C.
Modern solar inverters that use maximum power point trackers generate disturbances into both the grid's AC power line and the DC side of the solar module. An AC filter is normally used on the grid's AC power line, but the noise generated on the DC side tends to be overlooked, according to Schurter. EMC standards EN 61000-6-3 and EN55014-1, however, also put limits on the noise generated from lines not connected to the grid, such as the line to the solar panels. Meeting these limits can be achieved by using a DC filter on the DC side of the inverter.
The FMER SOL DC filters are designed with screw clamps for types up to 150 A and copper bars for types upwards of 250 A. Other types of connections, such as wires or copper bars under 250 A, are available upon request. Small adjustments can also be made to the electrical circuit or to the filter housing upon request, the company adds.