CIRCUIT ARRANGEMENT AND METHOD FOR OPERATING A CIRCUIT ARRANGEMENT

Abstract

A circuit arrangement for generating a three-phase rotating field at least at an electrical consumer including at least one mains voltage input including a single-phase alternating current, a first phase strand connected to the mains voltage input and the electrical consumer, whose transported voltage includes a first outer conductor, a second phase strand, whose transported voltage corresponds to a second outer conductor, an energy storage, a switching element, through which the energy storage can be connected via a third phase strand for generating a third outer conductor, and a control unit that can detect at least one trigger point of the first phase strand and the switching element can be actuated at least at a detected trigger point of the first outer conductor of the first phase strand to close or open the third phase strand and to generate the third outer conductor.

Claims

1. A circuit arrangement for generating a three-phase rotating field at least at an electrical consumer comprising: at least one mains voltage input comprising a single-phase alternating current, at least one first phase strand connected to the mains voltage input and the electrical consumer, whose transported voltage comprises a first outer conductor, at least one second phase strand connected to the mains voltage input and the electrical consumer, whose transported voltage corresponds to a second outer conductor 120 offset from the first outer conductor, at least one energy storage, which is connected to the mains voltage input and in which at least temporary electrical energy is able to be stored, at least one switching element through which the energy storage is able to be connected via a third phase strand with the electrical consumer for generating a third outer conductor, and at least one control unit by means of which at least one trigger point of the first phase strand is able to be detected and the switching element is able to be actuated at least at a detected trigger point of the first outer conductor of the first phase strand to close or open the third phase strand and to generate the third outer conductor.

2. The circuit arrangement according to claim 1, wherein the control unit comprises at least one sensor means, at least one calculating unit and/or at least one signal generator controllable by the calculating unit, by which a signal for opening or closing the switching element is able to be generated and passed and/or sent to the switching element.

3. The circuit arrangement according to claim 2, wherein the at least one sensor means comprises a synchronization circuit by which at least one positive/negative transition at the mains voltage input is able to be detected.

4. The circuit arrangement according to claim 2, wherein the calculating unit comprises a CPU and/or if the signal generator controllable by the calculating unit comprises a sinoidal pulse width modulation, wherein the calculating unit has an algorithm stored in the calculating unit for driving the signal generator, which comprises a sine function or relies on tables stored in the calculating unit.

5. The circuit arrangement according to claim 1, wherein the switching element has an output stage with at least one driver.

6. The circuit arrangement) according to claim 1, wherein the energy storage comprises at least one energy storage means and/or the energy storage comprises at least one transformer.

7. The circuit arrangement according to claim 6, wherein the energy storage comprises at least one rectifier arranged between the first phase strand and energy storage means and/or between the second phase strand and energy storage means.

8. The circuit arrangement according to claim 1, further comprising at least one measuring means arranged between the at least one switching element and the electrical consumer.

9. A method of operating a circuit arrangement for generating a three-phase rotating field according to claim 1, comprising the steps: commissioning of the circuit arrangement by switching on or connecting the mains voltage input; possibly charging the energy storage device through the mains voltage input; detecting a suitable trigger point at least on the first outer conductor of the first phase strand by the by the sensor means of the control unit; calculating an opening time of the switching element, in which a third outer conductor offset by 240 from the first outer conductor is able to be generated by the energy of the energy store, by the calculating unit of the control unit and by opening or closing the switching element by a signal generator of the control unit on reaching the opening or closing time.

10. The method according to claim 9, further comprising the steps: depositing a run-up current in the calculating unit and/or detecting the run-up current by the measuring means; limiting the run-up current by the control unit.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The drawing shows:

[0045] FIG. 1 is a schematic, electrical circuit diagram of a first embodiment of the circuit arrangement;

[0046] FIG. 2 is a schematic, electrical circuit diagram of a second embodiment of the circuit arrangement;

[0047] FIG. 3 is a schematic flow diagram of the method according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0048] FIGS. 1 and 2 each show an electrical circuit diagram of embodiments of a circuit arrangement provide the reference numeral 2. The circuit arrangement 2 is used to generate a three-phase rotating field. This is generated on an electrical consumer 4, such as an induction motor.

[0049] In the exemplary embodiments shown in the figures, the circuit arrangement 2 comprises a mains voltage input 6. From the mains voltage input 6, a first phase strand (=u1) 8 leads to the electrical consumer 4. In the first phase strand 8, the voltage carried in the first phase strand 8 comprises a first outer conductor L1. In addition, the circuit arrangement 2 comprises a second phase strand (=v1) 10 connected to the mains voltage input 6 and the electrical consumer 4, whose transported voltage comprises a second outer conductor offset by 120 from the first outer conductor of the first phase strand 8.

[0050] In addition, the circuit arrangement 2 comprises an energy storage 12, which is connected to the mains voltage input 6 and in which at least for a short time electrical energy can be stored.

[0051] In addition, the circuit arrangement 2 in the exemplary embodiments shown in FIGS. 1 and 2 in each case comprises a switching element 14, by means of which the energy storage 12 can be connected to the electrical consumer 4 via a third phase strand 16.

[0052] In addition, in the embodiments shown in FIGS. 1 and 2, the circuit arrangement 2 comprises a control unit 18, by which at least one fixed trigger point of the first phase strand 8 is detected and the switching element 14 is controllable with least one detected trigger point on the first outer conductor of the first phase strand 8 for closing of the third phase strand 16 and for generating a third outer conductor.

[0053] The two exemplary embodiments of the circuit arrangement 2 according to FIGS. 1 and 2 are common in each case in that the control unit 18 in each case comprises a sensor means 20. The sensor means 20 comprises in the embodiments shown in the figures, a synchronization circuit 22, such as a trigger, through which at least one positive/negative transition at least on the first outer conductor of the first phase strand 8 can be detected.

[0054] In addition, the control units 18 each comprise a calculating unit 24 and a signal generator 26 that can be controlled by the calculating unit 24.

[0055] Through the signal generator 26, a signal for opening or closing of the switching element 14 can be generated and can be conducted and/or transmitted to the switching element 14. The signal generator 26 may be, for example, a pulse-width modulation generator.

[0056] The computing units 24 of the control units 18 may comprise a CPU in which an algorithm or a table 28 can be stored.

[0057] FIG. 1 shows a first exemplary embodiment of the circuit arrangement 2, in which the energy storage 12 comprises an energy storage means 30 connected to the first phase strand 8. Between the energy storage means 30 and the first phase strand 8, a rectifier 32, such as diode, is arranged. As a result, the energy storage means 30 of the energy storage 12 of the first embodiment is always charged with electrical energy when the first phase strand 8 is located in an outer conductor deviating from a zero phase.

[0058] In addition, in the exemplary embodiment shown in FIG. 1, a measuring means 34 is provided which is connected to the calculating unit 24.

[0059] FIG. 2 shows an exemplary embodiment of the circuit arrangement 2, in which the energy storage 12 comprises two energy storage means 30 and two rectifiers 32. As a result, an operating voltage of +/310V is generated and temporarily stored by this D2 two-pulse doubler circuit.

[0060] In addition, the exemplary embodiment according to FIG. 2 comprises an output stage 36, which can be functionally assigned to the switching element 14 and can be converted into high-power and voltage-high signals by the weak control signals of the calculating unit 24.

[0061] FIG. 3 shows a schematic flow diagram of the mode of operation of the circuit arrangement 2. With the aid of the circuit arrangements 2 of FIGS. 1 and 2, the method is described below:

[0062] In a first step 100, the circuit arrangement 2 is put into operation. This takes place by switching on or connecting the mains voltage input 6.

[0063] In a subsequent step 101, the energy storage 12 is charged by the mains voltage. This takes place in each case as long as the respective outer conductors are not in their zero crossing.

[0064] In a further step 102, a negative/positive transition, such as zero crossing of the mains voltage is detected by the sensor means 20 of the control unit 18.

[0065] Following this, in a step 103, a closing and opening time of the switching element 14 is calculated by the computing unit 24, at which a third outer conductor offset by 240 with respect to the first outer conductor L1 can be generated by the energy of the energy store 12. Upon reaching this closing or opening time, the switching element 14 is closed or opened, which takes place by the signal generator 26 of the control unit 18.

[0066] The features of the invention disclosed in the foregoing description, in the claims and in the drawing, may be essential both individually and in any combination in the realization of the invention in its various embodiments.

REFERENCE LIST

[0067] 2 circuit arrangement [0068] 4 electrical consumers [0069] 6 mains voltage input [0070] 8 first phase strand [0071] 10 second phase strand [0072] 12 energy store [0073] 14 switching element [0074] 16 third phase strand [0075] 18 control unit [0076] 20 sensor means [0077] 22 synchronization circuit [0078] 24 calculating unit [0079] 26 signal generator [0080] 28 table [0081] 30 energy storage means [0082] 32 rectifier [0083] 34 measuring means [0084] 36 output stage