DE1538351A1 - Three-phase generator that can be driven with variable speeds - Google Patents

Description

P 15 58 351.4 (B 88 100 VIIIb / 21c) R. 86? 0

Robert Bosch. GmbH, Stuttgart November 8, 1968 Rb / Sz

Three-phase generator that can be driven with variable speeds

The invention relates to a variable speed drive Three-phase generator, in particular three-phase alternator for vehicles, with a three-phase output winding, which can be connected downstream, preferably via a rectifier, to a consumer, in particular a battery. . -

In the construction and design of three-phase alternators for vehicles, various demands are made, some of which contradict each other. Such an alternator should already deliver a current at low speeds (city traffic) that is large enough to charge a battery. This requirement is best met by an X-switched three-phase alternator. Such an alternator should deliver the highest possible current even at its normal operating speed. This requirement is best met by a three-phase alternator connected in a triangle (delta). Furthermore, such an alternator should be as small as possible, since it can easily be accommodated in the engine compartment of a motor vehicle or on the chassis of a railroad car. | can. For this purpose, a good degree of efficiency is required at as many speeds as possible during operation, so that the temperature does not rise too high despite the small size. This requirement contradicts the fact that Y-switched three-phase alternators have their maximum efficiency in the lower speed range, whereas those switched in a triangle have their maximum efficiency in the upper speed range.

With the known three-phase alternators are so in the construction and design, only compromises are always possible: either you get a current that is large enough even at low speeds

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is to charge a battery, but then has to be with the normal Operating speeds only a relatively low current available. Or you can do without the battery when it is low Speeds and can then draw a large current at the operating speeds.

It is an object of the invention to overcome the disadvantages of the known Avoid alternators. In particular, it's a job of the invention to create a three-phase alternator for vehicles which, with good utilization of the active copper and iron Already deliver a sufficient charge current for a battery at low speeds and at the same time at normal operating numbers can deliver a large current.

According to the invention, this is achieved in a generator mentioned at the beginning by a changeover switch, which switches the output winding in one switching position in star connection and in another switching position in delta connection, as well as by a control device that controls the changeover switch depending on an operating parameter of the three-phase generator. The control unit is set so that it switches the output winding in the star in the rest position and at low speeds so that it can already deliver sufficient current to the battery. After switching, however, this winding is connected in a delta and can then deliver a current that is approx. 75% greater than with the star connection at the operating speeds for which the generator is designed.

There are various alternatives for operating the control unit: which each have top and drawbacks and therefore each can be used according to requirements, possibly also in combination.

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One alternative is characterized in that the load current is used as the operating parameter, so that when exceeded a certain load current the changeover switch from star to Delta connection is reversed. This has the advantage that the changeover switch at low load currents, i.e. when idling, is not operated at all and is therefore subject to little wear. A certain disadvantage, however, is that that just when a load is switched on, the changeover switch is also actuated, with brief voltage and load peaks can arise.

Another alternative is characterized in that, so that the changeover switch is switched over from star to delta connection upon exceeding a certain frequency is used as loading% operating parameters, the output frequency of the generator. For this purpose, z. B. a speed-dependent switch of the type used in large numbers in single-phase AC motors to switch the auxiliary phase. However, purely electrical solutions are also possible, e.g. B. with components (inductors, capacitances) that have a frequency-dependent "resistance.

The frequency-dependent control has the advantage that the three-phase generator is immediately ready to deliver a large current above a certain speed. On the other hand is with her " the disadvantage that with speed changes every time the set switching frequency is run through - and that can happen with one Automobile very often be the case - the toggle switch is pressed; this is therefore subject to more rapid wear.

In a further embodiment of the invention, the generator is with Advantageously designed so that the control device has a semiconductor switch, in particular a switching transistor and a voltage-dependent Contains resistance with non-linear characteristics, in particular a Zener diode. I am such a device

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operates securely and requires very little space, so it is straight can be built into the generator. As a semiconductor switch, for. B. also a {thyristor can be used.

Another embodiment of the invention is characterized by means of a device for briefly interrupting the excitation current at the moment of switching from star to delta connection or the other way around. Does this go there? Switching process without current or almost without current in front of you and the switch can be dimensioned smaller.

Further details and advantageous developments of the invention result from the embodiment described below and shown in the drawing.

Show it: .

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Robert Bosch GmbH --jt "Br" 8670 "

Stuttgart "July 15, 1966 Rb / SI

Fig *. 1 shows the circuit of a three-phase generator with a

Switching _{device according to the invention 4} I ¹ Ig ₁₅ 2 and 3 Schaubzllder gum explaining the Schaltimg according to Fig «U

In fig * 1, a three-phase alternator 10 with one off three single windings 11,12,13 "existing three-phase Auagängswieklung and an excitation winding 14 shown. The connections of the three phase windings K 11, 12, 13 are in the usual way of describing »and that has the phase wiok» lung Ii the Phaaenansohluss UX * the Phaenwlcklung 12 die Phase connections pf, and the phase winding 13 the connections

The one one-phase windings 11, -12.13 are electrically connected via the contacts of a switch indicated by 15 »This switch has a solenoid 16 is actuated ₈ of the four change-over '17.18 _S 19» 20, and indeed will, upon actuation of the solenoid 16 first the changeover contact 20 and only then the changeover contacts 17 to 19 are set in motion

The connection X iat with the switching arm of the changeover contact 19, the connection t with the S & naltarm of the changeover contact 18 and -dor connection T, with the switching arm of the Uraachaltlrontakta 17 firmly connected ^ These «switching arms are in the rest position of the three-phase generator 10, so in the tension-free decorative tape des Slektroinagneb'en 16., each connected to a contact a! the contacts a aler three switching c-τυη bars 17 * 18,19 are in with each other

* h \ ru the JSlekt.magnet 16 at tor o ^ .io.n ^ oeetnt, so keep an fl; .e üchaltarme jewuLlo on alnen K.oiv -. <iki; Ό. ΒγΓμ, ι 'JfiiiS.chaltlfC-nfcakt' l ^f ) Li-f, diex; ev iCop.ia! Rt b -ai-; · 1; -.- τα An.i h-'ifi V, b «i.-tu (Π> ·: <: h 11 ί.Κπν, ί., _: Ί _; ι ίβ .jit the Λίί-ch iiL [i, '/' Ma-! hv-.i lifu-it.nU; Lmil, .iU τ. VI iulf, Ί> i, i in · OC.h i-Uli U Verbuildbi! i4,! il :: LH! ^F , .U .. '), J Ui ' ii ", ilffii." Ru-) .; tt'ili Mi. i Mir ί '.

Ii - ■! 2-.il ·> iiu - .. '. Η'αίϊ-.ίΐΜΐΊ "(Mf. R -ι · ι · - :. <·' ■ '- ' i ■ -. ·. ·: !. v'u f * l.- ·· ') ■ i T ^<;:. i have i'alb'3t luüI <let ieue · · ϊί οί <π iaa; .-; ^"1!.'! i ^^ a ϊ '^ \: ι \' -oiira-

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1S38351

Robert. Boson GmbH ° "E ₀ Ke * 8670

Stuttgart I5.?o1966 Rb / Sl

of the electromagnet 16 in ! delta connection «

la the connections U ₉ V ₉ Y / is a with 23 toeseielia®t © r. Three-phase "Brüeksngleiehrlchter connected ,, of a G-leichstromneta · - fed _f äosaen PluaLeitojsg, with 24 'and its aa let © connected © Mlsiueleitung 25 foeseicamst SINCL. In addition, the anode of one of three rectifiers 26 aage s oiilo ss en ρ aersii cathodes are connected to each of the di® "connections? U ,, ¥ r _{; W and at which a direct current is taken to feed the excitation winding 14. This direct current} If you turn a voltage regulator, known as 27, sr type stettert ₅ so that the span between lines 24 and 25 remains approximately constant. its other terminal is connected to the field winding 14, the other terminal of which is in turn connected to the switching arm of the switching contacts SO? the other two contacts of this changeover contact are connected to ground

On the line tohi connection. 7 / the primary coil of a current converter 28 is switched _{on to the rectifier 23 and 26 Ρ} a bridge rectifier 29 is connected to the secondary coil of the rectifier tied together.! The positive output of this rectifier is connected via a connection A to the one electrode of a capacitor 33 and one connection of a po'hentiomöber 34 '! the different view of this potentiometer is sov / le- the other .electrode of the capacitor 3 '*> are ' with. der jSilivmalelfcung 25 yerbundon- «The tap of the i? otenti.ometerf; 34 int connected with the IC, vi; hod © .einor Zenördioda 55 , lie in .0 --v vor lie ^ ο π den Sciialtung ain apannuniiöabhfiii-riser Nir'-zvfitei id «f / ^ fe _Q ^ - © An -.?.-j died-- · Zo - η. ·)>'ill ode Int: an ili.v: Barria flo'.r ΐ .-.'. ιη.Ί L ^ , m'ü 32 αηίΓ ⁵ .ο ⁽ ίΙι "i-osuiiti, deep! ·

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Robert Bosch GmbH R ₀ No. = 8670

Stuttgart $ 1 * 7 »1966 Rb / Sl

sen collector with one terminal of the electromagnet 16 and the anode of a rectifier 36 is connected. The other connection of the electromagnet 16 and the cathode of the rectifier 36 are connected to the positive line 34 «,

The circuit according to Hg _4-1 works as follows «When the generator 10 is idle and at low speeds, the electromagnet is de-energized and the changeover contacts 1T ₄ Ie ,, 19 are in the position shown * so that the three phase windings 11;» Are connected in Y 12,13 * If now the current flowing through the primary winding of the current transformer 28 load current a certain ^, at the tap of the potentiometer 34 adjustable value exceeds _9, the voltage at the output of the rectifier 29 is so large that the zener diode 35 'which at low voltages was closed begins conduct "au and a base current in the transistor 32 flows ■ * a result, this transistor becomes conductive and a current flows from the positive wire 24 through the electromagnet 16 _e the collector and the emitter of the transistor 32 to the negative line 25, the electromagnet 16 is therefore excited and switches over. Here, the changeover is first operated and gebr-- in its center position ⁿ ht _s in which it interrupts the connection of the field winding 14 to earth, so that the generator is eStregt / or their voltage drops "Thereupon, then the change-over 17 to 19aus their position a brought b in the position and at the same time the Umschal is tkontakt 20 brought to its upper position _s so that the field winding 14 can be energized again, "the phase windings 11 to 13 are now connected in a triangle, that is, its output voltage is at first small, however, they can deliver a higher phase current. With the aid of the voltage regulator 27, the current through the field winding 14 is now increased until the desired voltage is again between the lines 24 and 25.

The capacitor 33 is advantageously dimensioned so large (Z ₁₅ B ₀

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Robert Bosch GmbH ■ R ₆ No. 8670

Stuttgart 15 * 7 * 1966 Rb / Sl

that during the interruption of the excitation currentB uni the after * »;

following decrease of the phase tetrome. the voltage between the <

Point A and the Mlnusleitung 25 only 'decreases 30 that the;

Switching! State of the transistor 32 is retained until the Pha-. senstrom in the current transformer 28 has again reached its old value «. ■

Outside it is advantageously possible, in series with the resistor 34 between this and the point A, to .schalt a further.Widerstand, which is switched on at low speeds, but is short-circuited when switching over the switch 15. One gets a .Schalthysterese for the transistor 34 "ie" it switches only at a relatively large Phasenötrom to _three: delta connection and to aurück again "to Y only when a smaller Phasenetrom 3chaltung * Likewise, also in place dea switching transistor 34 and the Zener diode 35, a Schmitt trigger used weräen i _{wherein the hysteresis can be easily adjusted kanne

If 3? Ahrzeuges the speed of the alternator 10 below a certain value decreases during standstill of, the 'load current is lowered through the primary winding of the current transformer 28 so fätark from that the voltage at the rectifier 29 is no longer sufficient _y to keep conducting the Zener diode 35 . The transistor 32 is, that is, blocked again and the current through the electromagnet 16 is interrupted. This creates an inductive counter-voltage at the electromagnet 16 _S, which causes a current through the rectifier 36 and thereby prevents damage to the transistor 32. When the electromagnet 16 is then de-energized, the switchover contact 20 opens first, so that the field winding 14 is de-energized again and Switching position a brought back, whereby: at the same time the reversing contact 20 also returned to its lower switching position. The phase windings 11 to 13 are then switched back to Y and can also be switched to low

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BATH ORIGINAL

¹ '- ■ ■ C ₅ , 9 ^

Robert Boach GmbH R ₀ No. ₀ 8670

Stuttgart 15o7n1966 Eb / Sl

pay another current that ZoB _{9 is} sufficient to charge a »battery not shown» connected to lines 24,25 »

The use of a current transformer 28 is particularly appropriate for larger three-phase alternators "because the losses in such a current transformer are very low. In the case of smaller Liohtmaschinen it is sufficient to arrange a resistor 37 in the negative line 25 through which the load current flows" and the one with A marked point at the point A "of the negative line 25 at the output of the rectifier 23" The mode of operation of the circuit is then the same, but current converter 28 and rectifier 29 can be omitted * The voltage drop across resistor 37 results in losses ₉ which are often undesirable _a

In L? Ig ₀ 2 of the phase current of the alternator 10 for various circuit types let illustrated with 40 the curve is referred to. indicates the phase current as a function of the speed for Y-switching «With 41 is the curve which indicates the phase current as a puncture of the speed for delta connection ₅ As can be seen borrowed with Y-connection, the phase current in the normal speed range is significantly lower than with Delta connection. » The invention e- "gives the thick, drawn-out Stromkurvö, which combines the advantages of both circuits aarten

In Pig ", 3 and the efficiency curves 42 (with Y connection) and 43 (with delta connection) are shown" As can be seen, curve 42 has _{its maximum at a lower speed n 2} , while curve 43 has its maximum at a higher speed Has maximum, which has about the word η ₂ o By the invention, both effect maxima are 'exploited _v which is shown by the bold curve' .. Since the heat losses are significantly lower in a device according to the invention, the generator can be used werdon. "

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Claims (8)

Robert Bosch GmbH, Stuttgart November 8, 1968 Rb / Sz Expectations u) Three-phase generator that can be driven with variable speed, in particular Three-phase alternator for vehicles, with a three-phase output which, preferably via a Rectifier, a consumer, in particular a battery, can be connected downstream, characterized by a changeover switch (15), itfelcher the output balance in a switching position in star connection and in another switch position in delta connection, s> as by a control device (32 to 35) » which controls the changeover switch (15) depending on an operating parameter of the three-phase generator (10). 2. Three-phase generator according to claim 1, characterized in that the load current is used as the operating parameter, so that at Exceeding a certain! »Branch current of the switch (15) is switched from star to delta connection. 3- three-phase generator according to claim 1 or 2, characterized in that that the output frequency of the generator is used as the operating parameter, so that "when a certain Frequency of the changeover switch (15) is switched from star to delta connection » - 2 - 909840/0678 Documents (Art. 7 j $ l Abs. 2..Nt., 1.S.aU3.defl amendment;} «! '!. v. 4. ü. 19S7) BATH ORIGINAL 4 ·. Alternator after. Claim 2, characterized in that that the control unit (32 "to 35) is connected to the output of a current transformer (28) in the circuit of a generator phase connected. 5. Three-phase generator according to claim 2, characterized in that that the control device (32 to 35) is connected to a resistor (37) which is in a rectifier (23) is connected to the generator (10) DC circuit (24, 25). 6. Three-phase generator according to one of claims 1 to 5 _5, characterized in that the control device (32 to 35) contains a semiconductor switch, in particular a switching transistor (32) and a voltage-dependent resistor with non-linear characteristics, in particular a Zener diode (35). 7 three-phase generator according to claim 6, characterized in that it is marked that the changeover switch is designed as a contactor (15), wherein the semiconductor switch (32) the current in the contactor coil (16) controls, and that a rectifier (36) is arranged parallel to the contactor coil, which has opposite polarity is like the semiconductor switch (32). 8. Three-phase generator according to one of claims 1 to 7 »^ characterized in that the control device (32 to 35) is set to a current value which corresponds to the intersection of the current characteristics (40, 41) corresponds to delta and star operation, 909840/0678
BATH ORIGINAL so that the switch (15) ″ reversed at this current value will. 9 «Three-phase generator according to one of claims 1 to L ^ t exier field winding, which is fed via a voltage regulator eil regf? 8trom, characterized by a Einrieirtnag (20) for brief interruption of the excitation current in the ÄU4-.oiblick ■ switching from star to Delta connection or Wi , .reverses. 909840/0678
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