DE2721967A1 - SPARK CONDUCTORS FOR PHASE-GATE CONTROLLED SEMI-CONDUCTOR CIRCUITS - Google Patents

Description

Radio interference suppression chokes for phase control Semiconductor circuits.

The invention relates to a Ftinkentstördrossel for phase control Semiconductor circuits, consisting of a soft magnetic toroidal core with an insulated winding. The toroidal core is made of two parts composed, both made by pressing ferromagnetic powders be, one part of the core using insulating binders known from the mass core technology, the other part of the core being pressed without a binder.

Phase-angle controlled semiconductor circuits are increasingly used in various areas of electrical engineering to control consumer currents and loads in AC circuits, e.g. for control purposes of motors or to regulate the brightness of light sources.

The rapid switch-on processes of such switches cause considerable Interference voltages according to regulation 0875 of the Association of Germans Elektro-Techniker (VDE) in the frequency range 0.15 to 30 MHz must be attenuated to a certain permissible level by suitable interference suppression means.

As a suitable means for radio interference suppression of such semiconductor switches under Taking into account the installation dimensions and the costs involved, the series connection of a toroidal core choke with a capacitor resulted. This The interference suppression element is connected as a voltage divider in parallel to the semiconductor switch and This dampens the interfering signals that arise in the switch and run into the consumer circuit on the supply lines.

The throttle is traversed by the consumer current and, due to the low frequency of the consumer circuit, usually 50 Hz, does not represent a significant value Inductive resistance. At the high frequencies of the interference voltages, however, the inductive resistance must be high, especially at 150 kHz, since this Frequency the interference voltage is greatest. As high an inductance as possible at 150 kHz is therefore required of the choke, correspondingly of the choke core the highest possible permeability at this frequency.

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Vogt GmbH & Co KG, Erlau liber Passan Re: patent application: radio interference suppression chokes for phase control controlled RaTb.

This interference suppression circuit has an undesirable ripple effect. The choke and capacitor form an oscillating circuit that closes when the semiconductor switch is switched on and generates natural oscillations when it is switched on is stimulated. The frequency of the natural oscillations is between 5 and 20 kHz. The superposition of consumer and oscillating currents in the shark circuit breaker results Current fluctuations that can cause unintentional, disruptive switching processes. With light controllers, for example, they cause flickering fluctuations in the brightness of the connected light sources.

This side effect can be avoided by adequate damping of the mentioned Avoid natural vibrations. It has been shown that the required damping can only be achieved through sufficiently large losses of the throttle core can, because additional circuit measures within the semiconductor switch, such as the insertion of a resistor, the consumer circuit in an impermissible manner load or reduce the interference suppression too much. For the core material Accordingly, high losses in the frequency range 5 to 20 kHz are required.

The two requirements mentioned, namely high permeability at 150 kHz and It is well known that high losses at the comparatively much lower frequencies of 5 to 20 kHz contradict each other when they are applied to a homogeneous soft magnetic material. Either the material is broadband and maintains its permeability up to high frequencies; in this case it always has small losses at low frequencies or it has at low frequencies Frequencies high losses, but this is always associated with a strong decrease in permeability at higher frequencies.

Although in some applications with homogeneous choke cores a well usable one If a compromise between the two requirements is possible, no suitable magnetic core material can be found for many applications that meets the opposing requirements. This is particularly the case when small dimensions with higher performance are required in the consumer group.

In these cases, combined throttle cores are used, which are composed of two partial cores made of different soft magnetic materials:

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Vogt GmbH & Co KG ₅ Erlau via Passdu * ' ^c ' Re: patent application: radio interference suppression chokes fin phase control half.

1. From a "permeability-bearing" partial core that is broadband and sufficient permeability ensured at 150 kHz;

2. from a "loss-bearing" part of the core, which has high losses at 5 to 20 kHz and thus ensures the necessary damping of the undesired natural vibrations. However, it does not make an effective contribution to Permeability at 150 kHz.

It is also required of the radio interference suppression choke that its costs correspond to the total costs of a semiconductor switch. Since the in semiconductor circuits mainly used switching elements, such as capacitors, resistors, Thyristors etc. have become considerably cheaper in recent years, the radio interference suppression choke is also required to be of low cost. I.e. but that expensive materials and complex manufacturing processes must be avoided to an increasing extent.

The German Offenlegungsschrift 2 119 950 describes a two-part throttle known whose permeability-bearing partial core consists of a ferrite ring with an air gap. The loss-bearing part of the core is formed by punched and layered Electrical or deep-drawn sheets. This solution requires grinding in the air gap and because of the layering of the sheets, a lot of effort in the Manufacturing. This means that the requirement for radio interference suppression equipment that is reasonable in price cannot be met. In addition, the sheets generate magnetostrictive ones Vibrations that are audible and that are perceived as acoustic disturbances in many applications, e.g. in household lighting controls (dimmers).

In the German Offenlegungsschrift 1 813 643, a throttle is also used proposed a two-part core. The permeability-bearing partial core consists of a nickel-copper-iron alloy rolled out into thin strips with additions of manganese, molybdenum and chromium. The loss-bearing part consists of strips or sheets made of iron with the addition of silicon or aluminum. the Composition of the alloys for the permeability-bearing part is core chosen so that the magnetostriction is very low. This eliminates the disadvantage of disturbing noise development, the alloys used, the

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Re: patent application: radio interference suppression chokes Γϋ »phase control half.

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Contains 74 to 84% nickel, rolled into strips, but are used as the core material too expensive and do not allow the construction of an inexpensive radio interference suppression choke.

German Offenlegungsschrift 2 505 080 also proposes one two-part throttle core, in which expensive materials can be avoided. The permeability-bearing part consists in this case of iron powder, the is pressed with an insulating binder. The loss-bearing part of the core is formed by an annular winding of iron wire, which is inserted into the Form is inserted so that it is embedded in the toroidal core after pressing and surrounded on all sides by the iron powder. This solution undoubtedly brings from On the part of the materials used, a cost reduction, but requires the production and the piece-wise insertion of the wire winding measures that must also take place in addition to the simple powder pressing and additional facilities require. In particular, it is necessary to fill the iron powder into the die before and after the wire coil is inserted, i.e., to fill it two phases. In addition, a device for manufacturing and centric Precisely fitting insertion of the wire wrap is necessary.

The present invention is based on the idea that both partial cores in conventional pressing process for mass cores without additional measures.

It has been found, surprisingly, that when pressing Commercially available and cheap soft magnetic iron powder types with grain sizes between 10 and 600 ym without the addition of insulating binders loss-bearing Partial cores can be manufactured so that the required high damping in the frequency range 5 to 20 kHz in combination with a permeability-bearing Part of the core is given. The properties of this partial core by the pressure, the grain size and the grain size distribution of the powder as well as influenced by a light heat treatment and adjusted to the desired values. It has been shown that the electromagnetic properties Such cores, in particular the losses in the range 5 to 20 kHz, can be kept within the tolerances required for mass production required are. It has also been shown that the strength of the without binder

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Vogt GmbH & Co KG, Erlau via Passäi.

Re: patent application: radio interference suppression tools for phaser.gate-controlled halves.

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Pressed kernels are completely sufficient and only insignificant from the strength distinguishes cores that are usually used as mass cores with binders in chokes.

With the method according to the invention, it has therefore become possible to manufacture the loss-bearing sub-cores for radio interference suppression chokes using the same simple pressing process as the permeability-bearing sub-cores, in the same operation and in the same mold without any additional measures, which means a considerable simplification in the manufacturing process.

A major advantage of the process is that permeability and losses of the combined two-part core apart from the above-mentioned pressing factors and the heat treatment of the loss-bearing part core by the Volume ratio of the two partial cores can be influenced. In terms of manufacturing technology, this is very easy by choosing the appropriate heights of the partial cores possible during pressing. A change in the volume ratio is desirable, for example, when two capacitor types with two different capacitance values are used in a semiconductor switch for interference suppression. At the higher capacitance value, higher attenuation at 5 to 20 kHz is required Inductance at 150 kHz can be lower. With a smaller capacitance value, on the other hand, the attenuation can be lower, but a higher inductance is used 150 kHz required. The throttle properties are simply adapted to the various conditions by setting the corresponding press heights when producing the two partial cores.

The two partial cores are put together, together - as known - with one insulating protective layer covered and wrapped.

Figure 1 shows an embodiment of the radio interference suppression choke according to the invention. (1) and (2) are the two partial cores that are coated together with the insulation (3). (4) is the wrapping. This choke is a version that is suitable for brightness regulators (dimmers) for the control of Powers between 60 and 600 W are suitable. The outside diameter of the combined

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Vogt GmbH & Co KG, Erlau via Passdu * " ^f *

Re: patent application: radio interference suppression, -drosselη flit phase control half.

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and coated core is 39 mm, the inner diameter 20 mm and the Height 8.5 mm. The volume ratio of the permeability-bearing partial core to the The loss-bearing partial core is 1.5 in this example. The winding consists of 140 turns of enamelled copper wire with a diameter of 0.75 mm. These Choke suppresses interference in connection with a capacitor with a capacity of 0.22 yF the semiconductor switch so that the required degree of interference N according to the VDE regulation 0875 is complied with. The choke according to the invention thus meets the requirements placed on it, although cheap materials and essential Simplified manufacturing processes can be used.

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Claims (7)

Claims l.) Radio interference suppression choke for phase-angle controlled semiconductor switches, ^ - consisting of a toroidal core and an insulated applied winding, wherein the toroidal core is made from two iron powders by pressing Partial cores (1) and (2) is composed, each of which has a permeability and form a loss-bearing part core, characterized in that the loss-making part is pressed from iron powder without the use of insulating binders. 2.) radio interference suppression choke according to claim 1, characterized in that the permeability-bearing part core made of iron powder is pressed with insulating binder, the proportion of binder preferably between 0.15 and 0.45 wt.%. 3.) radio interference suppression choke according to claim 1 and 2, characterized in that for Both partial cores iron powder with grain sizes between 10 and 600 μm can be used. 4.) radio interference suppression choke according to claim 1, 2 and 3, characterized in that the ratio of the volumes or heights of the loss-bearing to the permeability-bearing part of the core is preferably in the range between 0.5 and 1.5. 5.) radio interference suppression choke according to claim 1, 3 and 4, characterized in that the loss-bearing part of the core is subjected to a heat treatment with temperatures of up to 200 ^° C. 6.) radio interference suppression choke according to one or more of the preceding claims, characterized in that instead of iron powder during manufacture one or both part cores of soft magnetic alloyed powder types can be used. 7.) A method for producing a radio interference suppression choke according to claim 1 to 6, characterized in that both part cores are made in the same mold. 8098Ä6 / 0534 ORIGINAL INSPECTED