DE1000508B - Pendulum inverter with contacts working in parallel - Google Patents

Description

GERMAN

Pendulum inverters are known to consist of a chopper and a subsequent transformer. The chopper delivers to the transformer an alternating current with a trapezoidal curve shape with steep edges. As a result, the harmonic content is of the generated alternating current is very high. This is very disadvantageous in some cases, e.g. B. if an all-current receiver or all-current battery receiver optionally from an accumulator wants to operate a pendulum inverter. Then the heating current branch is connected to that of the pendulum inverter supplied, high-harmonic alternating current, which results in strong hum.

The invention overcomes this disadvantage. It refers to a pendulum inverter, consisting of a chopper and a transformer, with contacts working in parallel at times, of which the one contact is directly connected to the transformer winding, while the other contact is connected to this winding via a resistor or a choke. According to the invention Resistance or the throttle between the two contacts dimensioned like this and the contact arrangement like this hit that one contact closes the circuit so much later or opens it so much earlier that the generated alternating voltage is approximately sinusoidal. Work when applying the invention so at times two contacts in parallel.

It is known to provide a chopper with contacts working in parallel in order to generate the current to distribute two contacts, but here1> ei is not the achievement of a sinusoidal alternating current intended and not achieved either. This is because there are both contacts in the known chopper each connected to the transformer winding via a choke, as it is practically impossible to achieve that both contacts close and open at the same time. So it will generally be first only one contact can be closed. In order to avoid that this one contact is immediately full Absorbs current, a choke is connected upstream to slow down the increase in current. Since not to be foreseen is which of the two contacts closes or opens first, there must be one before each contact Throttle can be switched. In the case of the invention, on the other hand, the times of contact closure or -Opening so far apart that this time interval is already outside the tolerance limits. That's why a throttle is only switched in front of the contact that closes first.

The circuit used in the invention, in which the one contact via a resistor and the other contact is connected to the transformer winding without resistance is known per se.

Pendulum inverter with parallel
working contacts

Applicant: Telefunken G. mb H.,
Berlin NW 87, Sickingenstr. 71

Hans Haupt, Hanover,
has been named as the inventor

In the known circuits, however, the contact closings take place with a very short time Shift so that no large losses can occur in the resistor. Here is not thought of the possibility of achieving an approximately sinusoidal curve shape. In the inventive If necessary, the losses can be dimensioned by using a throttle keep a resistance low.

Fig. Ι and 2 show two embodiments of the invention;

Fig. 3 shows the waveform of the current achieved. In Fig. Ι a resistor R is connected between the contacts α and b and between c and d. The contacts are set so that first the contact α and then the contact b closes. The same applies to contacts c and d, which belong to the other half-wave of the alternating current.

In Fig. 2 the resistances between the con ^ clocks replaced by throttles.

Fig. 3 shows the current curve during a half-cycle of the alternating current. In During the time from 1 to 2, only one contact is closed. The current rise is due to the resistance or the throttle slows down. From time 2 when the second contact is closed, the current rises faster again until it has reached the maximum value. At time 3 the the latter contact reopened. Because of the contact lying in front of the other, then only effective contact Resistance, the current drops slowly. At time 4 this other contact is also opened, so that now the current drops more steeply.

This curve shape is only effective if the load is predominantly real. This is true if the heating circuit of an all-current receiver is directly connected to the secondary winding of the transformer

is connected. A rectifier with a charging capacitor can be connected to the same transformer Connect to generate anode voltage. This circuit is because of the charging capacitor only the upper part of the curve is decisive, because it is known that the charging capacitor is only charged then takes place intermittently when the supplied voltage exceeds the voltage of the charging capacitor.

On the secondary side of the transformer T in Fig. Ι is a capacitor C of z. B. 0.2 μ ¥ connected in parallel, which is used to tune the secondary coil to the frequency of the pendulum inverter. The series connection of filaments H and possibly a series resistor W is shown as a load.

Claims (2)

PATENT CLAIMS: i. Pendulum inverter, consisting of a chopper and a transformer, with at times contacts working in parallel, one of which has a contact via a resistor or a Choke and the other contact directly without resistance or choke with the transformer winding is connected, characterized in that the resistor or the throttle between the two contacts is dimensioned and the contact arrangement is made so that the immediately contact connected to the transformer winding closes the circuit so much later or opens it so much earlier that the generated AC voltage is approximately sinusoidal. 2. Pendulum inverter according to claim 1, characterized by using it to supply alternating current to the heating current branch of an all-current receiver or all-current battery receiver from an accumulator. Considered publications:
German patent specification No. 715 336. 1 sheet of drawings © 609 740/169 12.56