M80 SERIES: MULTI-E CHOKE

Features:

Introduction

PREMO GROUP introduces a new high energy storage chokes standard series for inverter applications. It is developed both for DC and AC inverter chokes. Its high inductance values (up to 5mH) make them perfect for high eficiency solar inverter aplication. It handles powers up to 10kW. The M80 series is based on a combination of high performance multi-E sendust alloy (Kool Mì) cores and rectangular copper wire.This kind of combination allows us to offer the highest efficiency inductor (>99.5%) in the market on a reduced dimension. The M80 series exhibits excellent stability and reliability at high temperatures. Because of the distributed air gap, the inductance shift with temperature change is relatively small. Due to its high Curie temperatures of powder core alloys, changes in saturation characteristics are minor over normal operating temperature ranges. Also, it is resistant to thermal shock and is rated for continuous operation up to 200°C.

Advantages

1.- It has none of the the thermal aging concerns associated with powdered iron cores. Due to the magnetics parts are pressed with a non-organic insulating material; no binder is used, so there is no problem, even when the cores are operated continuously at high temperatures (up to 200ºC)

2.-Main characteristic over powdered iron is its lower core losses and over silicon steel is its much lower core losses, which becomes more dramatic as the frequency increases. For switching regulator inductors, the effect of AC current produces a high frequency magnetic field which creates core losses and causes the core to heat up, this effect is lessened with M80 series making inductors more efficent and run cooler.

3.- It offers similar DC bias characteristic when compared to iron powder.

4- It has near zero magnetostriction, eliminating the noise associated with powder iron cores, ferrite, or silicorn iron lamination, when they are operated in the audible range from 20 Hz to 20kHz (filter inductors).

5.- Sendust alloy has a high saturation level (Bsat= 1 T) that provides a higher energy storage capability , that can be obtained with gapped ferrite, resulting in smaller core size (with more than twice the flux capacity of ferrite, at a typical 50% roll-off design point, this can result in a 35% reduction in core size). Avoiding as well as the gap loss problem associated with ferrites (fringing flux).

6.- It has a soft saturation (sharp saturation for gapped ferrite or silicon steel blocks with discrete gap), in some cases, this swinging inductance is desirable since it improves efficiency and accomodates a wide operating range. With a fixed current requirement, the soft inductance versus DC bias curve provide added protection against overload conditions (fault-tolerance).

Inductance vs Temperature

The non-magnetic material separating small particles, results in a distributed gap in powder cores. The inductance shift with changing temperature in the M80 series is relatively small. This is largely due to the distributed gap, as well as to the stability of the alloys used. Even though the magnetic alloys used in the powder cores show greater changes in permeability with temperature, the effective permeability of the material is dramatically stabilized by the presence of the distributed gap. The absolute permeability in the gap is the magnetic constant (¥ì=¥ì0 ¥ìr), no matter what the temperature is, because gap is made with a non-magnetic material (¥ìr=1). Consequently, the lowest permeability cores, having the largest effective gaps, exhibit the most temperature stability. The M80 series presents a decrease of inductance lower than 6% at 200¨¬C.