RHF-Active

Highly efficient active harmonic filter

The RHF-Active is available as a 3-level IGBT based filter, but also as unique Silicon Carbide (SiC – MOSFET) based Active Filter! These technologies offers significant benefits in performance and efficiency.

The efficiency of a SiC harmonic filter is >98% and therefore produce about 57% less heat than comparable solutions based on IGBT technology. Looking at the RHF-Active as a Harmonic solution for drives, the system efficiency is >99.3%. For drives <200kW this is even more efficient than RHF two-stage passive harmonic filter.

The efficiency of a 3-Level IGBT based Harmonic filter is >97% and therefore produce 41% less heat, than comparable solutions based on 2-Level IGBT Technology. Looking at the RHF-Active as a harmonic solution for drives, the system efficiency is >99%.

Das RHF-Active kann für Blindleistungskompensationen, Ausgleich von unsymmetrischen Belastungen, zur Vermeidung von Oberschwingungen verwendet werden oder zeitgleich alle Netzverzerrungen bedämpfen. Für die Eliminierung von Oberschwingungen kann der THDi auf ein beliebiges Niveau skaliert werden, um Normen oder Richtlinien wie beispielsweise die IEEE519-2014 einzuhalten.

The RHF-Active may be used for pf correction, unbalance compensation, harmonic mitigation or altogether. It reduces the harmonic current distortion of non-linear loads and sources to any required THDi. This is necessary to reach various standards and recommendations, such as IEEE 519-2014.

A high switching frequency allows for efficient and accurate compensation of high order harmonics up to 61st. Due to its unique circuit, the RHF-Active is extremely efficient which allows for a very compact design. All RHF-Active can be used as 3P4W or 3P3W for 380-415V systems (further voltage levels coming soon!). Unlimited current possibilities due to open end in parallel setup!

RHF Aktiv Diagramm

The working principle of an active REVCON Harmonic Filter RHF-Active is completely different from any other harmonic solution. Instead of working as a line filter with tuned passive filter circuits, the active solution is connected in parallel and injects harmonics. These injected harmonics are of inversed polarity and therefore eliminate the harmonics taken from the supply.

Application

RHF-8P

<8% THDi

RHF-5P

<5% THDi

RHF-Hybrid

~1% THDi

RHF8P
Active
Scalable

Vaiable Frequency Drives – VFD

Yes

Yes

Yes

Yes

Water and wastewater treatment

Yes

Yes

Yes

Yes

HVAC

Yes

Yes

Yes

Yes

Pumps and Fans (VFD)

Yes

Yes

Yes

Yes

Industrial/ Factory Process (VFD)

Yes

Yes

Yes

Yes

DC charger

Yes*

Yes*

Yes

Yes

Buildings

Yes

Yes

Yes

Yes

Data Center (power supply)

No

No

Yes

Yes

IEEE 519-2014 requirement

Yes*

Yes

Yes

Yes

Marine

Yes

Yes

No

No

IEEE 519-2014 specified application

Yes

Yes

Yes

Yes

Electronically comutated / EC Motor

No

No

Yes

Yes

Non symetrical Load

No

No

No

Yes

Symetrical load multiple VFD

Yes

Yes

Yes

Yes

Symetrical load multiple equimpment

No

No

No

Yes

Displacement factor correction („pf“)

No

No

No

Yes

Unbalance compensation

No

No

No

Yes

Ideally all loads and sources have a pure sinusoidal current waveform. But unfortunately the true waveform of most equipment is very different. Nonlinear loads like for example the diode input bridge of a 6 pulse drive, are causing a distortion of the mains voltage. This distortion typically evaluated by the Total Harmonic distortion THD, evaluates frequencies from the 2nd up to the 40th harmonic. In a 50Hz Network this is the area between 100Hz and 2kHz.

The impact of the voltage distortion is diverse, and the most typical effect is overheat of transformer and PFC applications  (Capacitor banks). Underestimated impacts of harmonic distortion is the significantly reduced lifetime expectation of electrical  and mechanical equipment.

The Revcon Harmonic Filter (RHF) avoids the harmonic distortion of nonlinear loads and sources. The filter is not tuned to a specific frequency, but works like a bandwidth filter, reducing all frequencies up to the 50th harmonic. The RHF filter reduces the Total Harmonic Distortion of the current (THDi) to a level significantly below 5%. This is necessary to reach various standards, for e.g. IEEE 519-2014, who are getting more and more common.

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