FI123700B - Choking for an inductive component and process for its preparation - Google Patents

Description

Inductive Inductor Throttle and Methods of Making it

The invention relates to a method for producing an inductive component, such as a choke on a dudt filter 5, and to a method for producing an inductive component, as described in the preamble of claim 1.

Dudt filters are used to retard the rise and fall edges of pulse width modulated (PWM) voltage, e.g. engine drives and wind generators. This is to prevent harmful overvoltages from occurring when using long motor cables. The name dudt comes from the terms du (delta u) or voltage change and dt (delta t) or time change. Thus dudt 15 (or rather du / dt) means a change in voltage per time change. The filter is a low pass filter and consists of a choke and a capacitor. It is a well-known principle of dudt filters that when a rapidly changing voltage is applied to the filter choke, the filter capacitor 20 is charged slowly through the choke, whereby the output voltage from the capacitor is slower variable. However, the Dudt filter itself may cause a voltage surge to the output voltage as the charge pulse energy stored in the choke also discharges into the capacitor. Thus, the filter must have damping, otherwise the filter itself

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9 causes excessive voltage overshoot to output voltage.

Voltage surge suppression can be accomplished with a resistor in series with the filter condenser-x £, by means of a resistor parallel to the choke, by using a choke core failure for 30 minutes, or a combination thereof, [Paul T.

^ Finlayson, "Output filters for PWM drives with induction mo tors," IEEE, 1997]. These are commonly known techniques. The use of the inductors' own losses for attenuation 2 is based on the design of the inductor at loss at the frequency of the voltage overshoot. Conventionally, the dudt filter voltage overshoot suppression, when used for cardiac loss, is set by means of a choke impedance step. Usually silicon steel laminate is used as the core material.

However, setting the voltage damping of the dudt filters to the desired level as described above is difficult, if not impossible, since the impedance phase settles at a level set by material permeability, inductance, geometric parameters, and gaps, and is not easily . In addition, it is difficult to cool the laminated core structure, since the laminated structure causes a discontinuous heat transfer point and hot spots may occur in the structure. It is also difficult for laminated cores to make chokes of appropriate shape, often to a limited geometry, since the laminated structure is two-dimensional in nature, meaning that it will only work well in limited orientations. A further problem with laminated silicon steel is that its inductance decreases as the frequency increases. Although the inductance of a laminated silicon-steel choke at 50Hz is suitable for dudt filtration, it will generally fall below the frequency at which dudt filtration occurs (e.g. 100kHz coo 25-1MHz) due to the poor high-frequency

c \ j J

co women. This will reduce the dudt damping and this must be compensated i by increasing the capacitance of the filtering capacitor, x which increases the cost and losses, cc

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The object of the present invention is to eliminate the aforementioned non-LT3 T-sites and to provide an optimal damped choke o c \ | especially for use with a dudt filter. It is also an object of the invention to provide an inexpensive and reliable method of manufacturing said choke. Such a 3-choke filter can be used to flexibly filter the pulse-width modulated (PWM) signal. The inductor of the invention is characterized by what is set forth in the characterizing part of claim 1.

Correspondingly, the method according to the invention is characterized by what is stated in the characterizing part of claim 11. Other embodiments of the invention are characterized in what is set forth in the other claims.

Other inventive embodiments may also be disclosed in the specification of this application. The inventive content contained in the application may also be defined otherwise than as set forth in the claims below. In addition, it can be noted that at least some of the features of the subclaims can be considered as inventive as such in appropriate situations.

An advantage of the solution according to the invention is, inter alia, that the voltage over-damping of the dudt damped filter can be easily adjusted. In addition, the filter can be efficiently cooled and made flexible and efficient. In addition, such a filter is compact and fits in a small space.

co-25 The invention will now be described in more detail in the

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with reference to the accompanying drawings, in which: Fig. 1 shows a wiring diagram of an LC low pass filter,

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g) Fig. 2 shows the output voltage of a commonly known dudt filter co g 30, δ Fig. 3 shows an experimentally measured impedance phase of a commonly known dudt filter choke as a function of frequency, 4 Fig. 4 shows the input and output voltages of a non-attenuated dudt filter, Fig. 5 shows the measured permea-5 integrity of the core material of the silicon steel laminate and the dudt filter according to the invention as a function of frequency, Fig. 6 shows the choke components, coil and core with air gap, and the PWM signal generation by the Fig. 8 shows the input voltages of the fully attenuated dudt filter, and the resistive current of the reactor, Fig. 10 shows the input voltage of the dudt filter according to the invention. and output voltage as well as inductive and resistive current of the inductor, Fig. 11 illustrates by way of example a heat treatment profile of a core member, Fig. 12 illustrates a core member and a vortex current induced by a magnetic flux coo, Fig. 13 a core component of the invention, cc

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Fig. 15 shows the impedance steps of the choke m LO 25 measured at different revolutions, o δ ^ Fig. 16 shows a sectional end view of a dudt filter according to the invention, Fig. 17 shows a possible structural part of the inductor core of the dudt filter according to the invention. Fig. 18 shows a liquid-cooled dudt filter 5 according to the invention and Fig. 19 shows an air-cooled dudt filter according to the invention.

Fig. 1 shows a wiring diagram of a dudt filter 1 consisting of a choke 2 and a capacitor 3. Generally, the known principle of a dudt filter 1 is that when a fast alternating voltage 7 is applied to the left end of the choke 2, the capacitor 3 slowly charges through the choke 2. a slower alternating voltage is obtained at the right end 4. The capacitance of the cable to be connected to the filter may also serve as a filtering capacitor, whereby a separate physical capacitor 3 may not always be required.

Fig. 2 shows the shape of the output voltage 4 of the commonly known dudt filter 1. It is seen that the output voltage 20 4 has a voltage overshoot 5, which is however clearly attenuated. As mentioned above, the suppression of the voltage surge can be accomplished with a "resistor in series with the filter capacitor, by means of a resistor parallel to the choke, by utilizing the losses of the choke core or by

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S5 with 25 combinations. These are generally known techniques, i

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The use of a choke core loss to suppress the voltage surge is attractive, since no separate co g suppression components are required. Conventionally, the damping of the dudt filter tension 30, the cardiac loss when used, is set by the inductor impedance phase. As generally known 6, the inductive and resistive part of the inductor (ZL) of the inductor (ZL), of which the resistive part represents losses: ZL = jo) L + Rs 5 The ratio of inductive to resistive impedance sets the impedance phase so that 0 ° corresponds completely to impedance lossless. Figure 3 shows the measured impedance step 6 of a 3-phase silicon steel laminate choke as a function of frequency. It is seen that in the frequency range 10 where attenuation is required (here e.g. 100kHz-3MHz), step 6 is about 54 °. This provides voltage suppression suppression. However, the level of damping is difficult, if not impossible, to control, since in commonly known solutions the impedance phase of the inductor is set to a certain level determined by the material properties and geometry, and cannot be freely regulated.

Figure 4 shows the rising edge 7 of the PWM signal with dashed line and the dudt-20 filter output voltage 4 as an approximate line. It is seen that the filter output voltage 4 changes slower than the input voltage, i.e. PWM voltage 7. In this case, the filter produces dudt / attenuation . However, it is seen that the filter causes a voltage overshoot 5c q to the output voltage 4, since the energy stored in the choke during the charging pulse c1j qjj is discharged into the capacitor, cp ^ There must be attenuation in the filter, otherwise the filter itself causes excessive voltage 5 the term overshoot means the mentioned

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^ nite crossing). The value of the input voltage 7 is usually between 0 and

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° 30 DC link voltage between PWM signal and voltage

S

In fact, voltage overrun 5 is usually expressed as a percentage of the DC link voltage. The maximum voltage surge can be the size of a DC link, whereby the voltage overshoot is 100% and the absolute peak output voltage is 2 x DC link voltage. It is noteworthy, therefore, that a dudt filter should have both dudt (rise rate) and overshoot (voltage overshoot) attenuation.

5

Yet another aspect that reduces the performance of known dudt filters is illustrated in Figure 5. It is seen that the permeability 8 of silicon steel laminate decreases as the frequency increases. In contrast, the permea-10 Bilateral 9 of the core material of the invention remains constant for high frequencies. Considering the dudt damping against this point, the problem with laminated silicon steel is that its inductance and hence dudt damping decreases with increasing frequency. At low frequencies, the inductance to the inductor is limited and limited by the saturation of the cardiac material. Thus, when using silicon steel laminate at a frequency at which dudt filtration occurs (e.g., 10OkHz-1MHz), a much lower inductance is achieved than is limited by low-frequency saturation. The dudt attenuation is then reduced and this must be compensated by increasing the capacitance of the filtering capacitor, which increases the cost and the losses.

In addition, the above-mentioned properties of silicon steel laminate give rise to the following problems: 1) Due to the high low frequency coo 25 permeability, the low frequency inductance increases

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co easily unnecessarily large, and it is not possible to use o more winding turns to minimize the mass of the throttle core. Because the permeability of the heart of the invention is lower

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pi, multiple winding turns may be used to minimize the mass of the tensile core S 30. 2) Silicon steel laminate

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? operates at high frequencies resistively and not inductively, whereby the filter functions as RC or LC type. In this case, the filter has unnecessarily large losses and a steep rising edge, especially at the beginning of the rising edge. 3) The characteristics of the silicon-δ laminate-based choke, such as damping, are set at a certain level, and it is not easy to adjust the properties from said level to another, more suitable level.

5

In the following, the operation of the core 10 as a damping element of the dudt filter 1 is considered in the time domain. Fig. 6 shows a choke 2 having a core 10 having an air gap 12 and a winding 11. In addition, Fig. 6 shows how the PWM-10 voltage 7 can be generated by breaking switch DC 14 with a switch 13. The inductance of such an air gap choke can be calculated:

L

l i / H

core gapr ^ r 15

When the switch 13 is closed, an increasing current begins to flow in the coil 11 of the choke 2 according to the formula below:, Ut

Li 20

Fig. 7 illustrates waveforms of voltage and current of a non-attenuated dudt filter. When the rising edge 7 of the input voltage is connected to the filter at time t_0, the current 15 ”starts to rise in the choke as voltage is applied across it (PWM input ^ 25 output voltage 7 - output voltage 4). This power will also start charging

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Thus, the output capacitor S5, when the output voltage 4 begins to rise, n- Voltage across the choke (PWM input voltage 7 - output voltage 4) x £ is thus not constant and the choke current 15 increases only g until output voltage 4 is charged to g 30. to the same value as the voltage 7, i.e. up to t_l.

The current 15 of the choke 2 cannot, at that moment, turn off extremely fast, but begins to decrease as the energy of the choke 2 passes to the output capacitor 3 shown in Fig. 1.

9 The output capacitor 3 is charged by the energy flowing from the choke 2 and a voltage overrun is generated 5. The current 15 of the choke 2 is zero at a time when the voltage 4 of the output capacitor 3 is 2 x the input voltage 7, i.e. at time t_2. This phenomenon causes a harmful voltage surge 5. The voltage surge is thus caused by the energy stored in the choke 2 being discharged into the capacitor 3.

Figure 8 shows how eddy currents 16 are induced in a homogeneous core 10 pressed from an insulated iron-10 powder. It is seen that, unlike in a laminated structure, these flow smoothly in the structure. The reason is that the material resistivity, or resistivity, of the material 10 of the core 10 is limited, and the alternating magnet-15 pulse 20 inducing the voltage 7 coupled to the windings 11 induces a current to the core 10 which tends to reverse the induced flux 20. i.e., their induced winding current 17 times the turns of winding 11 is equal to eddy current 16. In other words, the current 17 distributed to winding 11 tends to counteract the flux 29 caused by eddy currents 16. The amplitude of current 17 generated by winding 11 is directly proportional to the voltage it does not have the typical time delay of the inductive component. The current 17 generated in the winding 11 follows the formula I = co 0 25 U / R, where R is the equivalent resistance of the structure.

c \ j

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o

Fig. 9 shows a graph of the voltages x and current of a dudt filter with only 16 Q of eddy currents.

a resistive winding current of 17. Such a ti-σ> co 30 lumbar could occur, for example, if the inductance of the choke 2

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T- would be infinite. It is seen that in this case there is no bias voltage overshoot 5. This is because the eddy currents 16 have no energy storage as well as an inductive current 15. Similarly, the amplitude of the current 17 induced by the eddy currents 16 is directly proportional to the voltage across the winding. Thus, at time t_1, when the output voltage 4 of the filter is equal to the input voltage 7, i.e. when the voltage acting across the choke 2 is zero, the winding current 17 induced by the revirators 16 is also zero and no voltage overcurrent 5 is generated.

Fig. 10 is a graph of the voltages and currents of an attenuated dudt filter according to the invention in which the effect of an inductive current 15 and a resistive current 17 on the output voltage 4 is combined. It is seen that since the resistive current 17 also charges the capacitor voltage, the choke voltage overshoot 5 does not become very large. In other words, the eddy currents 16 can be thought of as a resistor at the choke 15 of the choke 2 through which the capacitor 3 is also charged. In this case, the inductive current 15 of the choke 2 does not grow as large as without such a resistor and the voltage overshoot 5 remains smaller. It is also noteworthy that the eddy currents 16 tend to override the inductive 20 component of the impedance of the inductor 2, so that the resistive loss should be only sufficiently large so that the dudt damping produced by the inductive component does not lose too much. In fact, for a good surge suppression, the inductive portion of the impedance should be large rather than small. Then the inductor 25 dense current 15 grows slowly and resistive, not voltage-

c \ j J J

co overcurrent current 17 is able to charge capacitor 3 o to a suitable degree. Often, it is also not appropriate that the resistive current 17 is too dominant because then cc

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the rise rate of the output voltage 4 can easily be too high o co 30, i.e. the dudt filtering is low. Thus, resistive current 17 and in-to-product current 15, and their relationship, should therefore be capable

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adjust. According to the invention, the ratio of inductive current 15 to resistive current 17 is adjusted such that the ratio is between 1: 10 and 10: 1.

11

The inductive charge current 15 and the resistive charge current 17 of the dudt filter 1 according to the invention can be controlled by using the components 19 extruded from the metal powder 5 insulated as the core material, and by changing the properties of the core material and its dimensions 19.

In particular, it can be utilized that magnetic cores pressed from iron powder tend to be heat treated, thereby reducing their hysteresis losses. At the same time, however, their resistance decreases. For the Dudt filter 1, a specially optimized heat treatment profile can be used to achieve optimum permeability and resistivity. Permeability can influence the magnitude of inductive impedance-15 and resistivity the resistive impedance. Fig. 11 shows, by way of illustration, such a heat treatment profile 18 in which the core member 19 is held at different temperatures T1, T2 for different times t1, t_2. The temperatures T1, T2, ... TN used are, for example,

20 hours between +200 ... + 800 ° C and holding times t_l, t_2, ... t_N

are, for example, between 10 and 120 minutes.

Figure 12 shows a core metal component 19 extruded from heat-insulated metal powder and since the current losses of vortex 25 follow the formula:

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cp f "'Peddy = f (T ^ core / E-bulk)

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X

Q.

can also be the physical size of the heart and resistance to weather o

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30 to achieve the desired voltage surge suppression 5.

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o> - From a manufacturing point of view it is advantageous to make a powder

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by making as large components 19 as possible. However, for damping and fabrication of the Dudt filter 1, it is preferable that the compressible member 19 be elongated 12 and mounted such that the magnetic flux 20 passing therethrough the maximum, i.e. the largest area of the member 19, maximizing the losses caused by eddy currents 16 within the range, for example, such that the losses are in the range causing 20-80% voltage surge. A filter made with such an angular member 19 is also more compact than, for example, a toroidal core, since the circular shape of the toroidal core does not fit optimally in a mostly rectangular device housing. The core 10 of the laminate 10 would also have to be installed so that the direction of the laminates is parallel to the direction of travel of the stream 20, which would limit the configuration possibilities of the core 10 of the choke 2. Instead, the core components 19 made of insulated iron powder can be mounted freely, since the flow 20 can run freely in all directions. When the compression direction of the component 19 of the core 10 is from above, the width and length dimensions A and B can be changed by changing the compression tool or by inserting adapter parts into the compression tool. Instead, the height dimension C can be changed during the pressing process by changing the amount of material 20 and the stroke length. This is a very flexible method. Similarly, the density of the material can be adjusted by adjusting the amount of material and the stroke length.

Different lengths of cable are used between the motor / gene-o generator and the dudt filter co connected to the converter output. For example, in wind generators the cable length is typically 80-100m. The length of the cable affects the capacitance of the cable ka-x and thus also the performance of the dudt filter. The gas

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as the length of the game increases and thus the cable capacitance increases, the permeability which remains stable at 30 ° promotes the maintenance of inductance 2 and thereby in the iron core according to the invention

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the magnetic flux density change rate in dB / dT remains high in relation to the rate achieved in silicon laminate steel. The high magnetic flux density change rate, in turn, is directly proportional to the damping ability of the iron core, whereby the iron core can be better damped even though there is less iron in the core, i.e. the iron core according to the invention may be more compact than prior art iron cores. Thanks to this feature, the voltage overshoot remains stable even though the cable length increases, but only up to a certain limit.

The material of the iron core according to the invention is characterized in that the permeability of the material remains high even at a high frequency, whereby the change in the density of the magnetic flux and the resulting eddy currents and further the losses caused by them occur at the desired frequency.

Similarly, in the prior art dudt filter made of silicon laminated steel, the voltage overshoot tends to change uncontrollably as the cable length changes due to the excessive proportion of damping dominating eddy currents, whereby the magnetic flux density change is too low / dT / d.

In practice, an attenuated dudt filter can be designed and fabricated iteratively such that a component 1 is constructed from the components 19 and the voltage curve generated by it is practically measured. After that: 1) components

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S3 19 changes directions, 2) component 19 is replaced with another size component, 3) component 19 is replaced with heat treated component 4, 4) component 19 is replaced with another material, and so on, and the effect of these changes on voltage is considered. curve shapes. In this way, the constituent configuration 14 best suited for each application, on which the filter 1 is based, is experimentally determined.

The structure of insulated iron particles also provides corrosion resistance to the core 5, since corrosion stops the particle insulation as it moves freely in the laminate direction in the laminate. Figure 13 shows the structure of a core 10 consisting of a laminate. Indeed, it will be seen that the corrosion could proceed freely in the individual laminates 10 on the roads 21, since the laminates have insulation 22 only in one direction. Instead, Fig. 14 shows that the insulated iron powder core 10 according to the invention is naturally insulated in all directions, since its constituent parts 19 extruded from insulated metal powder are already insulated in all directions.

Thus, it can be said that the invention brings efficiency and flexibility to the manufacturing process of the attenuated dudt filter 1 by: 1) adjusting the surface area of the component 19 to be molded, , compression parameters and heat treatment profile such that w with the optimum relative permeability δ ^ 25 ti is, for example, between 10 and 500, and the most optimal resistivity is, for example, between 0.1 and 50 mQm, 3)

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· The orientation of the structural members 19 may be altered as needed during the assembly step, 4) the core 10 of the choke 2 is resistant to corrosion O) better than the core made of silicon steel laminate and 5) the use of co g 30 standardizing structural members 19

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15

The choke 2 of the Dudt filter 1 consists of a core 10 and a coil 11. The coil 11 also affects the operation of the choke 1. Fig. 15 shows the measured impedance steps 6 of the inductors 2 with different windings 11 as a function of hair. It is essential that the impedance phase 6 of the inductors 2 having only one winding turn 23 is higher than the impedance 6 of the inductors having two or more winding turns 24. Since the low phase correlates with the damping, it can be stated that the two winding turns 24 are minimum-10. rpm for maximum damping. Such a coil 11 comprising two or more turns 24 is easily formed by using insulated cable or stacked conductor plates.

15 Because of the high losses of the attenuated dudt filter 1, particular attention must be paid to its cooling. The core 10 consisting of insulated iron powder effectively conducts heat from inside the core 10 to its surface. In order to dissipate heat from the surface of the core 10, it is good to leave openings in the air between the steps. For this reason, it is advisable to divide the conventional 3-phase choke into three separate chokes, thereby providing the core 10 with a significantly larger cooling surface. At the same time, the common-mode impedance also increases, which is advantageous for filtering common-mode interference.

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0 25 when doing so. Fig. 16 is a top view of a halo film showing how three separate chokes 2 are mounted on the device housing 2a so that the cooling air passing through the housing effectively cools the cores 10. Similarly, winding 11 is

CC

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cooling air, where it effectively cools. For the sake of clarity O) S 30, only one cross-section is drawn in connection with the heart 10.

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cut coil 11, although there are actually o more coil turns. In addition, it may be appropriate to place several thinner cables side by side rather than using a single thick cable, as this will result in a more flexible coil.

16

Fig. 17 illustrates how fluid cooling can be directly integrated into structural members 19 by making fluid passageways thereon or on their surfaces, such as groove 5 25 shown in Fig. 17. When two such structural members 19 are juxtaposed, a hole is formed remains in the opening formed by the grooves 25.

Fig. 18 shows a dudt filter 1 according to the invention having a liquid cooling integrated in the core 10. The filter 1 has three separate cores 10, which are placed on the bottom plate 27 and surrounded by a winding 11 using an insulated cable. Liquid cooling-15 tubes 26 are integrated into the cores 10. The winding cables 11 are pressed into the core 10 and cooled therein. The coil 11 consists of a plurality of thinner cables connected in parallel to provide a more flexible structure and more cooling surface from the coil 11 to the core 10. In addition, the cable ends 28 can be sized to be directly connected to optimum connection points in the hardware cabinet without additional, costly It is advantageous to make the filter 1 by first gluing the cores 10 from the components 19 so that the liquid cooling tubes 26 remain inside the cores 10. The binding cores 10 are placed on the base plate 27, the cables 11 are laid on the cores 10 and the cables 11 and the core 10 are pressed into place against the base plate 27 by a strap 30. Finally, each end 28 of the cable 11 is inserted through the core 10,

CC

CL

resulting in two coil layers. In addition, additional support portions σ> S 30 may be used to secure the base plate 27 of the chokes 2.

m o δ

Figure 19 shows that, alternatively, the choke 2 of the dudt filter 1 may be a three-phase choke. Hereby all three phases of the three-phase choke 2 are common to the choke core 10, each with its own vertical column 10a. In this case, it is advantageous to make the coils 11 superimposed on the stacked plates 11a. When the middle phase winding 11c is still lifted on or lowered to the lateral windings 11b, the space can be effectively utilized. Further, both the coil 11 and the core 10 are effectively cooled when the surfaces of the core 10 and the coil 11 have large planar and exposed areas for contact with the cooling air.

It will be apparent to one skilled in the art that various embodiments of the invention are not limited to the examples above, but may vary within the scope of the following claims.

co δ c \ j i

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o 1 ^ x

DC

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σ>

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c/o

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o δ C \ 1

Claims (16)

A throttle (2) of one having an inductive component, such as a capacitor (3), provided with a dU / dt filter (1), comprising an ethereal tone a core (10) and a winding (11), and said throttle 5 (2) is designed to dampen surges (5) in the voltage by utilizing and controlling the core losses in the core (10) of the structural parts (19), characterized in that the damping caused by eddy current losses overvoltages and the ratio between the inductive and resistive current is set in a cross-sectional area perpendicular to the direction of the magnetic flux (20) in the core (10) of insulated metal powder, substantially prismatic structural parts (19), with the aid of resistivity and permeability , in which structural members (19) are magnetic flow (20) arranged to flow through the largest cross-sectional area of at least one structural member (19). Throttle (2) according to claim 1, characterized in that the core losses are set at the desired value at the planning, assembly and / or operating stage by using substantially homogeneous structural parts (19) and by utilizing the position of the structural parts (19). , shape, material and heat treatment. co o 25 A throttle (2) according to claim 1 or 2, characterized in, CNJ co. That the core (10) consists of structural parts (19) in which o. The current paths of the eddy currents (16) by means of the shape of the construction x part (19) are selected so that the losses caused by the eddy currents (16) cc CL are in an interval which causes a voltage surge up to 20-80%. m o δ 4. A throttle (2) according to claim 1, 2 or 3, characterized in that the core material has a substantially constant permeability within the entire operating frequency range of the throttle. Throttle (2) according to any of the preceding claims, characterized in that the structural parts (19) are heat treated with an optimized heat treatment profile at different temperatures (T1, T2, ... TN) and different times (t_1, t_2, ... t_N) in order to achieve as optimal permeability and resistivity as possible. A throttle (2) according to any one of the preceding claims, characterized in that the core (10) is assembled according to the material best suited for each filter (1) made of structural parts (19), empirically and iteratively -accessible configuration of structural parts. 7. A throttle (2) according to any of the preceding claims, characterized in that the winding (11) is made of several parallel coupled insulated cables and that the winding (11) has at least two turns. A throttle (2) according to any of the preceding claims, characterized in that a coolant tube (26) is integrated in the core (10). 9. A throttle (2) according to any one of the preceding claims, characterized in that the ends (28) of the winding cables (11) are connected in a co-device cabinet to their final connection co-locations without special rails requiring connections and are expensive. . cc CL 10. A throttle (2) according to any of the preceding claims, characterized in that the winding (11) consists of a plurality of circularly stacked plaques (31). o C \ J 11. A method for manufacturing a choke (2) into one having an inductive component, such as a capacitor (3), provided with a dU / dt filter (1), said choke (2) comprising at least one core (10) and a winding. (11), and which throttle (2) is designed to attenuate surges (5) in the voltage by utilizing and controlling the core losses in the core (10) consisting of structural members (19), characterized in that it is achieved by means of eddy current losses. the attenuation of overvoltages and the ratio of the inductive and resistive current are set in a cross-sectional area perpendicular to the direction of the magnetic flux (20) in the core (10) of insulated metal powder pressed, substantially prismatic structural parts (19), by the resistivity and the resistivity wherein the structural members (19) are arranged to flow the magnetic flow (20) through the largest cross-sectional area of at least one structural member (19). 15 Method according to claim 11, characterized in that the core losses are set to the desired value at the planning, assembly and / or operating stage by using substantially homogeneous structural parts (19) and by using the position of the structural parts (19), shape, materials and heat treatment. Method according to claim 11 or 12, characterized in that the core (10) is assembled by structural parts (19) in co and 25, the flow paths of the vortex streams (16) being selected by means of the shape of the CNJ co structural member (19). The eddy currents (16) caused the losses are in an interval that x causes a voltage surge up to 20-80%. CC CL O) oo 30 14. A method according to claim 11, 12 or 13, characterized by LΓ)? The core (10) is assembled by substantially homogeneous structural parts (19) pressed by insulated metal powder, whereby the relationship between the core (10) and the material's permeability, resistivity and / or geometric mat is regulated. the inductive current (15) and the resistive current (17) in the final filter (1) while the capacitor (3) is charged. 5 15. A process according to any of claims 11-14, characterized in that during the fabrication phase of the core (10) the structural parts (19) of the core (10) are heat treated with an optimized heat treatment profile at different temperatures (T1, T2, ..). .TN) and different times (t_1, t_2, ... t_N) to achieve as optimal permeability and resistivity as possible. Method according to any one of claims 11-15, characterized in that the core (10) is assembled according to the material best suited for each manufactured filter (1), consisting of structural parts (19), empirically and iteratively the configured design of the structural parts (19), using one or more of the following steps: the filter (1) is made of structural parts (19) and the waveform generated by the filter is measured in a practical application, whereupon, if the configuration does not fit within the desired boundaries the configuration formed by the structural members (19) are disassembled and the directions of the structural parts (19) are further subtracted CM CO o 25. The structural parts (19) are replaced by structural parts of other format x DC CL 2 - the structural parts (19) are replaced by structural parts co § which have been heat treated in another way δ CM the structural parts (19) are replaced with structural parts 30 of other material, etc., and the effect one or more a of the said changes have been studied in the waveform and the iteration is repeated until the desired configuration is found. co δ c \ j CO o x IX CL CD m co m o δ C \ l