DE19754264A1 - Electrical torque converter with variable conversion ratio - Google Patents

Abstract

The torque converter has generator rotors (G1,G2) positioned on a drive input shaft coaxial to a generator armature (N2) combined with a motor armature (M3) mounted on a drive output shaft and provided with a short-circuit winding lying in the magnetic field of the drive rotor and the stator supported by the torque converter housing. The stator magnetic field is provided by an electromagnet supplied with an induced voltage of variable intensity.

Description

The invention relates to an electric converter and its regulations.

0. Specialty

Electric converters are generally known and are already being built.

The simplest type of electric converter consists of a generator that is rotated by an engine and an electric motor that turns the output.

A major disadvantage of this principle is that the efficiency of the Transmission as a product of generator efficiency and engine efficiency is bad and by two separate machines the installation space and the weight and price becomes too high.

In German patent application P 29 28 770 there is a single anchor to avoid these disadvantages the output shaft is provided, which is both the generator armature and the motor armature. When the The drive shaft, which excites the generator armature, induces it in this one current. The anchor is non-rotatable firmly on the output shaft and its windings are also from the magnetic field of the stator (stator) permeated.

To regulate the principle, two possibilities are shown, that with real torque conversion and with Coupling either only regulating the current in the rotor winding or in the stator winding provide.

In the first representation, the armature winding and the stator winding are connected in series with the intermediate collector for torque conversion ( FIG. 2c). Since a large current flows through the collector with a high conversion factor, this is overwhelmed or at least subject to high wear.

In the second illustration, an induction rotating field is controlled in the stand. The control of such However, the field of rotation for the services in question is likely to be very complex.

In the German patent application P 197 12 083, torque and speed control alone is known the relative strengths of the excitation magnetic field on the drive rotor and the magnetic field of the driven rotor intended. Such a regulation is possible without great effort.

The present patent application requests protection for a special structure of the in P 197 12 083 described electrical converter.

This structure and its function is described with reference to FIGS. 1-9. Two different concepts are presented.

1. Construction concepts

The two concepts work with two exciters in which the magnetic poles are not reoriented (DC excitation or permanent magnets). The realization possibility for this concept is in Chapter 3 justified.

FIG. 1 shows the circuit diagram of the arrangement of FIG. 2.

The externally excited, generator-acting rotor magnets G1 and G2 are fixed to the drive shaft, whose magnetic field strengths B ₁ and B ₂ can be regulated via the adjusting resistors W1 and W2. G1 induces the voltage U1 and the current I1 in the winding N1 fixed to the housing. N1 is short-circuited with the winding N _gest .

The reactance X1 is kept small with an adjustable capacitor C1.

Do you want z. B. always let the reactance X1 be 0 at every drive speed Received resonance.

This is possible for C1 = 1 / ω 2 | an _* L (explanations in Chapter 2).

G2 induces the voltage U2 and the current I2 in the winding N2 fixed to the output shaft. N2 is with shorted the rotor magnet M3.

With the capacitor C2 z. B. for a low speed difference between the drive shaft and Output shaft generates resonance.  

In Chapter 3 it will be shown that no frequency control is necessary for this arrangement, but that a motor force is always generated on the driven rotor between N _gest and M3.

Fig. 2 shows the basic structure of the first, improved transmission concept.

The drive shaft 101 has two rotors 102 , 103 with the excitation windings 104 , 105 , which are fed with direct current via slip rings 106 , 107 . The current strength of each excitation winding can be changed independently of one another via the control loops 109 , 110 , and the magnetic field B1 generated by the first excitation winding 104 and the second excitation winding 105 generated by the magnetic field B2 can be set as desired.

B1 magnetic field induced in the frame 112 in the winding 113 _died with N grinding a current of the voltage U. The winding 113 is short- _circuited to a winding 114 with k _* N loops which generates a magnetic field B _Gest in the frame 112 .

The output rotor 121 with the short-circuit windings 122 is arranged on the output shaft 120 . The short-circuit windings 122 are penetrated both by the second magnetic field B2 of the drive rotor and by the magnetic field B _{Gest of} the frame.

By adjusting the magnetic field B1 and the magnetic field B2, the torque and Gear ratio from input to output shaft can be changed continuously.

Fig. 3 shows a second approach for an improved transmission.

A pole ring with permanent magnets 131 is used in the drive rotor instead of the solution of FIG. 2, in which the voltage in the frame winding 130 is induced by an externally excited electromagnet ( 104 in FIG. 3). The adjustment at a given drive speed takes place by shifting the frame windings 130 , as a result of which the covering area or, in the formula for the induced voltage U = B _* l _* r _* ω, the length l is changed.

2. Torques on the gear shafts 2.1 Torque on the drive shaft

The torque M _on the drive shaft is composed

• a) the generator torque M ₁ between the drive rotor G1 and the frame winding N1 and
• b) the generator torque M ₂ between the input rotor G2 and the output rotor winding N2.

thats why

(2.1.1) M _an = M ₁ + M ₂

With

(2.1.2) M ₁ = r _{1 *} B _{1 *} l _{1 *} I ₁

Likewise

(2.1.3) M ₂ = r _{2 *} B _{2 *} l _{2 *} I ₂

With
r _1,2 = radius of the magnetic field gap 1 between the drive rotor and the frame and the magnetic field gap 2 between the drive rotor and the driven rotor
B _1,2 = magnetic field strength on the drive rotor in G1 or G2
l _1,2 = conductor length of the frame or output rotor in the magnetic field of the drive rotor
I _1,2 = current in N1 and Ngest or in N2 and M3

While the sizes r _1,2 and l _1,2 (in FIG. 2), B _1,2 (in FIG. 3) are given by design and B _1,2 or l _1,2 by setting the excitation currents or the Coverage area are freely selectable, I ₁ and I _{2 are} functions of different values.

It is

(2.1.4) U ₁ = l _{1 *} B _{1 *} ω _{an *} r _{1 *} sin (ω _* t)

With
ω _an = drive frequency = 2 _* π _* f = 2 _* π _* n _{an *} N _pol
f = frequency
n _on = drive speed p. sec
N _pol = number of pole pairs on the drive rotor
Then I ₁ becomes

With
R ₁ = ohmic resistance of the frame winding

L ₁ = inductance of the rack winding
C1 = adjustable capacitor

By controlling the capacitor C1 as a function of the drive speed n _an , X ₁ can be kept very small and constant.

When controlling C1 to C1 = 1 / ω 2 | an _* L ₁ , so that resonance is achieved at every drive speed, X ₁ always becomes zero.

For further analysis, we assume that

with K ₁ = value selectable via the capacitor. This turns (2.1.5) into

M1 thus becomes from (2.1.2)

with: 1 / √2 = AC factor
The strength B _{gest of} the magnetic field generated by I ₁ in N _gest becomes

With
N _gest = number of windings in the frame
µ _gest = permeability
l _Sp = coil length
You sit down

then applies

It is

(2.1.10) U ₂ = l _{2 *} B _{2 *} (ω _an -ω _ab ) _* r _{2 *} sin (ω _* t)

With
ω _an -ω _ab = difference frequency = 2 _* π _* f = 2 _* π _* (n _an -n _ab ) _* N _pol
f = frequency
n _on = drive speed p. sec
n _ab = output speed p. sec
N _pol = number of pole pairs on the drive rotor
Then I ₂ becomes

With
R ₂ = ohmic resistance of the output rotor winding
X ₂ = reactance of the output rotor winding

For the further analysis it is assumed that C2 will not be used. X ₂ thus becomes

X ₂ = I _{2 *} (ω _an -ω _ab )

with L ₂ = inductance of the output rotor winding
This turns (2.1.11) into

The torque M ₂ thus becomes

with 1 / √2 = AC factor
You sit down

Then it will be

2.2 Torque on the output shaft

The torque M _ab on the output shaft is composed of the direct torque M2 from the drive shaft and the torque from the frame

(2.2.1) M _ab = M ₂ + M _Gest

It is

(2.2.2) M _Gest = r _{Gest *} B _{Gest *} l _{Gest *} I ₂

With
r _Gest = radius of the magnetic field gap between the frame and the driven rotor
B _Gest = magnetic field strength on the frame
l _Gest = conductor length of the output rotor in the magnetic field of the frame
I ₂ = current in the conductor of the output rotor
and M2 is as given in equation (2.1.13).

It follows from (2.1.9), (2.1.12) and (2.2.2)

With

thats why

Then applies to the output torque

3. Control of the magnetic fields

The magnetic field in the rack upon rotation of the drive shaft to be tracked with reference to FIGS. 4-8. Then a voltage is induced in each induction loop 113 , the strands of which are penetrated by the magnetic field of two opposite poles, which leads to a current and thus to the formation of a magnetic field of the type shown. (For the sake of explanation, a lead of the voltage before the current is not taken into account.) A magnetic field B _{Gest of} the orientation shown is created in the induction loops 114 , but with the k-fold strength of the magnetic field generated in the induction loops 113 . No voltage is induced in the induction loops, the strands of which lie over the same pole.

With reference to FIG. 5, it is then clear how the magnetic field in the frame rotates with the magnetic field of the drive rotor.

Each of positions 1-4 is opposite to the previous one by shifting the poles of the Drive rotor opposite the induction loops by half a width of the induction loop differently. Between 1 and 2, the poles formed by the induction loops jump one Induction loop continues, between 2 and 3 they do not change and between 3 and 4 they change again an induction loop further.

If an induction loop 122 of the output rotor lies over the poles of the drive rotor, as shown in FIG. 6, and over the loops 114 of the frame, then a voltage is induced in the induction loop 122 by the poles of the drive rotor, the current of which in the position shown is that shown Poles S generated on the output rotor. The same applies to loops in which a current is induced in the opposite direction and which therefore enclose a north pole.

Fig. 7 shows that the magnetic poles in the driven rotor also run uniformly to the magnetic poles of the drive rotor.

As before, the poles 104 , 105 on the drive rotor are shifted by half a winding width between the windings 122 on the driven rotor between two images.

Starting from the bottom, between the first and second images and the third and fourth images, each pole generated by the currents induced in the loops 122 (by the relative movement of the drive rotor poles 104 , 105 to the loops 122 ) remains on the driven rotor, but the next loops that previously did not produce a magnetic pole orientation now create a magnetic pole.

Between the second and third image, the original magnetic poles go out and the next remain get.

The poles in the frame and in the driven rotor run erratically, but uniformly and parallel to the poles of the drive shaft.  

3.3 Effect of the stator magnetic field on the driven rotor

Fig. 8 shows the interaction of the poles in the frame and on the driven rotor. It is clear that since all the poles on the drive rotor, driven rotor and in the frame rotate uniformly with the poles on the drive rotor, the poles are always in the same position to one another. Therefore, the poles in the frame always have a driving effect on the poles on the drive rotor.

Fig. 8 shows for 3 different speed ratios of the output shaft to the drive shaft, the Polstellungen of driving slide to the frame.

On the far left is the output shaft, in the middle you have a gear ratio of 1: 2.5 on the far right you have a gear ratio of 1: 1.25.

It can be seen that the poles in the frame push against the poles at any transmission ratio the output shaft act.

4th example

An example gearbox is intended to show curves over the output speed at constant input speed 2400 RPM are demonstrated.

Interpretation:

Pole pairs on drive rotors: 8th axial length N1 0.12 m axial length N2 0.2 m axial length Ngest = axial length M3 0.2 m Winding N1 10th Winding N2 7 Winding M3 7 Winding Ngest 11 r1 0.03 m r2 = rgest 0.15 m

Calculation:

l ₁ 2.4 m l ₂ 2.8 m l _M3 2.8 m l _gest 4.4 m

It is assumed: µ = 6.25 _*

10 ^-4

The inductance L ₂ results

of the driven rotor: L ₂

= 0.00122 _d and K

= 0.0223

The line strengths and resistances are chosen so that K ₁ = 1, R ₁ = 1 and R ₂ = 0.5.

The capacitor C1 is regulated so that resonance is achieved at any speed. The capacitor C2 is dispensed with.
Then ω _an = 2 _* π _* n _{an *} N _pol = 2 _* π _* 40 _* 8 = 2010.
For ω _ab = 0: B _gest = K _{1 *} K _{gest *} B _{1 *} ω _{an *} r _{1 *} l _{1 *} 1 / √2 = B _{1 *} 2.28

With B1 = 0.9166 and B2 = 0.3106, M1 = 98 Nm, M2 = 154 Nm and MG = 1614 Nm
M _an = M ₁ + M ₂ = 252 Nm
and
M _ab = M ₂ + M _Gest = 1768 Nm

The following diagrams show the calculated torque curves over the speed ratio and the associated B1 and B2 for the assumed gearbox.

It can be seen that, although the design sizes were by no means optimal, the concept is very good satisfactory results can be expected.

Claims (6)

1. Electric torque converter with drive rotors (G1, G2; 102 , 103 ; 131 ) driven by a drive shaft ( 101 ), which coaxial with a generator armature N2; 121 and is connected to this rotatably connected motor armature M3, and a housing-fixed stand part (N2; 112 ; 130 ), which forms an electric motor together with the motor armature and in which generator armature (N2; 121 , 122 ), and motor armature (M3; 122 ) are connected to a common armature, the winding of which is a short-circuit winding, both from the magnetic field (B2) of a drive rotor (G2; 103 , 105 ) and from the magnetic field (B _gest ) of the stator (N _gest ; 112 , 114 ); is penetrated and in which the penetration of the armature by the magnetic fields (B2 and / or B _gest ) can be changed, characterized in that in the stator part (N2; 112 ; 130 ) the magnetic field (B _gest ) is generated by an electromagnet, the AC voltage is induced by the rotation of the input or output shaft relative to the stator and by adjusting the magnetic field strength (B1) of the inducing magnet (G1; 104 ) or the overlap length of the inducing magnet ( 131 ) with the windings in the frame ( 130 ) in it Thickness can be adjusted. 2. Electrical torque converter under claim 1, characterized in that on the drive shaft two generator rotors (G1, G2; 102 , 103 ) are fixed, of which the first the current in the windings (N1, N _gest ; 113 , 114 ; 130 ) induced in the frame and the second induced the current in the windings (N2, M3; 122 ) on the output rotor and the poles on the generator rotors of permanent magnets ( 131 ), in which the overlap length is changed, or of DC magnets ( 104 , 105 ) where the excitation current is changed. 3. Electrical torque converter under claim 1, 2, characterized in that the short-circuit winding (N1, N _gest ; 113 , 114 ; 130 ) is provided in the frame with an adjustable capacitor C1. 4. Electrical torque converter under claim 3, characterized, that the capacitor C1 is changed depending on the frequency of the alternating current so that the reactance of the rack windings assumes a desired value. 5. Electric torque converter under claim 1-4, characterized in that the control of the transmission at the desired input and output speed and the desired input and output torque by adjusting the current strength I1 of the frame magnet with the magnetic field B _gest and the current strength I2 in the output rotor and these current intensities at given speeds are regulated by setting the excitation currents of the inducing electromagnets G1, G2 or the covering length of the inducing permanent magnets ( 131 ). 6. Electrical torque converter under claim 1-5, characterized in that depending on the phase shift ϕ of the alternating currents of the stator can be rotated by a einen dependent angle ϕ that the magnetic field B _{gest of} the frame acts on the driven rotor motor.