Minimising harmonics in small loads with harmonic filters

Unlike many existing units, the new filter is specifically designed for small variable speed drives (VSDs) and is pre-configured to avoid the need for extra programming during set-up. It is also highly efficient and compact, meaning operators can maintain power quality while making the most of the space available in their facilities.

The new REVCON LHS-Active filter is specifically designed for small applications and can support VSDs of up to 5.5 kW. It is equipped with pre-set internal software so that the current transformers (CTs) and load are already built into the unit. Following installation, the operator just needs to input a power connection and take the output. As well as this, it sits in series without the load, avoiding the need for extra wiring, cabling, and programming, which would normally be required in most filtering systems.

By installing the new filter in series, operators can set up multiple units across their site and distribute their harmonic reduction capability, rather than relying on one large filter. Meanwhile, its compact build ensures that minimal floor space is taken up.

“The new LHS-Active filter is groundbreaking because it tackles harmonics in loads far smaller than any existing solution,” explained John Mitchell, global sales & marketing director at CP Automation. “The new filter is also 99% efficient and its power losses are extremely low at around 120W, helping businesses keep their energy costs under control without compromising on power quality.”

While many mitigation technologies use insulated-gate bipolar transistors (IGBT), the REVCON LHS-Active uses silicon carbide (SiC) power Metal–Oxide–Semiconductor Field-Effect Transistor (MOSFET) with Schottky diodes. This improves the filter’s low-loss capabilities and enables a switching frequency of 50 kHz, reducing total harmonic distortion (THD) from 35% down to below 5%.