Active Front End Converters

Active Front End (AFE) Converters are rectifiers providing:

• bidirectional power flow between DC and AC subsystems,
• low harmonic distortion of AC (mains) current,
• unity power factor.

They are used in situations where energy recovery is required or if energy quality improvement is considered. AFE converters may work for example as converters for solar or wind power plants, as well as converters in variable speed electrical drives with braking energy recovery (power saving). In modern wind turbines, AFE converters stabilize power flicker, stabilize dynamic mechanical loads on the generator's shaft as well as they realize maximum power point tracking algorithms (especially at weak wind conditions by maximally loading generator at slow rotational speed). Together with modern, light weight and efficient synchronous generators, AFE converters significantly improve wind power plant's efficiency.



Besides energy recovery ability, such converters achieve low input current harmonic distortion when they are used to transfer power from alternating current grid to the load.

AFE does not exchange reactive power with the line, but exclusively active power. Converter may be used to compensate power factor as well.

For high power applications, three-phase AFE converters are used.



Our AFE products are based on FPGA control IP-core available as a separate product.

Standard products

We offer AFE converters in power range from 15kVA to 200kVA in competitive prices. These products are sold in several configurations, especially:

• Simple AC/DC modules (rectifiers). These modules are used to replace diode rectifiers, e.g. in existing installations. Amongst others, they operate with standard frequency converters providing DC bus connection (as a bypass of diode rectifier). AC/DC modules are also used in many other applications, e.g. on-grid solar power plants.
• AC/DC/AC converters (so called back-to-back topology, depicted in the figure below). These converters are used for example in variable frequency electric drives or wind power plants.

(1) Electromagnetic environment class: 3 (EN 61000-2-4).
(2) Climate conditions according to class 4K4H (EN 50178) for IP-54 casing version.
(3) Current THD is usually <5%, depending on voltage disturbances.



Standard converters include: power circuits, mains side filter and chokes, basic communication interfaces, basic power flow control algorithms.

Maximum power point tracking algorithms, energy efficiency algorithms for inductance machines, power flicker stabilization, etc. on individual request.

We kindly invite you to contact us for a quotation.