Schaffner Emv Ag

California Institute of Technology

Andrzej Pietkiewicz

Slobodan Cuk

Fabian Beck

A harmonic cancelling interphase magnetic device () comprising a magnetic core of rectangular shape with three wound legs () and two non-wound legs (), wherein the cross-section of said non-wound legs () is thinner than the cross-section of said wound legs (). The magnetic device is designed for a front end multi-pulse rectifier or inverter. Its use enables reduction of the harmonics of the currents absorbed or injected to three-phase power line. Compare to known solutions, cost, material and dimensions of the magnetic device are significantly reduced.

Harmonic cancelling interphase magnetic device

An integrated magnetic for a low harmonics three-phase bidirectional front-end and also for AC/DC and DC/AC power converters. Its use enables reduction of the harmonics of the currents absorbed or injected to three-phase power line by using only one device which integrates a splitter and an inductor function. Compared to known solutions, cost, material and dimensions of the integrated magnetic device are reduced thanks to the magnetic core comprising three closed sub-assemblies and one or more jokes, separated by air-gaps from the sub-assemblies.

Integrated magnetic device for low harmonics three-phase front-end

An integrated magnetic device for low harmonics three-phase front-end () comprising The integrated magnetic device is designed for a low harmonics three-phase bidirectional front-end and also for AC/DC rectifier and DC/AC power inverters. Its use enables reduction of the harmonics of the currents absorbed or injected to three-phase power line by using only one device which integrates a splitter and an inductor function. Compared to known solutions, cost, material and dimensions of the integrated magnetic device are reduced.

A Passive harmonic filter (F) has an input node (B) for connection to a power supply (), an output node (C) for connection to a load () and an intermediate node (A). A first branch () located between the input node (B) and the intermediate node (A) has at least one first inductance (). A second branch () located between the intermediate node (A) and the output node (C) has at least one second inductance (). A third branch () is connected to the intermediate node (A) and has at least one capacitor (). The first, second and third branch thus build a low-pass T-filter. A damping branch () is provided having at least one first resistor (), where the damping branch is arranged in parallel to the first branch.

Harmonic filter

A soft-switching dc-to-dc converter for providing regulated voltage to a load combines the functions of loss-less soft switching at zero voltage and at a constant switching frequency on the primary side and soft switching at zero current on the secondary side of an isolation transformer for all load currents from full load to no-load and PWM output voltage regulation on the secondary side. This is made possible by using voltage bidirectional switching element in series with a low-pass filter on the secondary side and current bidirectional switching element on the primary side driven at close to 50% duty ratio with adjustable dead time between switching. The adjustable dead-time is realized by sensing voltages across paired primary side current bidirectional switching element in order to enable alternate turn ON of said pair only at zero voltage, thereby eliminating or greatly reducing switching losses under all load current conditions. The output voltage is regulated by PWM control of the voltage bidirectional switching element comprising one of the following: a bipolar transistor, or a MOSFET in series with a diode, or preferably a saturable reactor in series with a diode to form a magnetic amplifier on the secondary side.

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Burgdorf, Switzerland

Andrzej Pietkiewicz