spinning machine

Abstract

Spinning machine comprising a plurality of work stations with electric drives, in particular DC motors, and at least two DC voltage sources with voltages U1 and U2, each forming a DC voltage network N1 and N2. At least three DC voltage rails for powering a plurality of drives, in particular DC motors, are connected to the at least two DC voltage sources in such a way that a first DC voltage rail is in operative connection with a first DC voltage source, a second DC voltage rail is in operative connection with a second DC voltage source, and a third DC voltage rail is in operative connection with the first DC voltage source and the second DC voltage source. The current collectors of the plurality of drives, in particular DC motors, are optionally connected to the first DC voltage rail and the third DC voltage rail, or to the second DC voltage rail and the third DC voltage rail. The two DC voltage networks N1 and N2 are in operative connection with a voltage equalization device to compensate for voltage differences in the two DC voltage networks N1 and N2.

Description

Technical Field

[0001] The present invention relates to a spinning machine with multiple workstations, each workstation having an electric drive, particularly a DC motor, the electric drive having at least two DC voltage sources having voltages U1 and U2, each forming a DC voltage network N1 and N2; wherein at least three DC voltage rails are connected to at least two DC voltage sources to power the multiple drives (particularly the DC motors) in such a way that a first DC voltage rail is electrically connected to a first DC voltage source, a second DC voltage rail is electrically connected to a second DC voltage source, and a third DC voltage rail is electrically connected to both the first and second DC voltage sources, and wherein the current collectors of the multiple drives (particularly the DC motors) are optionally connected to the first and third DC voltage rails or to the second and third DC voltage rails. Background Technology

[0002] EP 1927686 A2 discloses a spinning machine with an electric drive and a power supply device for motors with DC and AC voltage sources. At least one transformer is connected to an AC voltage grid. Because a large number of very different motors are used in spinning machines, special attention must be paid to the individual needs of the different motors and their power distribution within the machine when designing the power supply. Therefore, the patent proposes designing the energy supply within the spinning machine in such a way that the existence of ideal voltage conditions depends on the type of motor and its location within the machine. For this purpose, two rectifier groups are connected to two secondary transformer windings, each of which is connected to two DC voltage rails, one of which is common to both rectifier groups, making three DC voltage rails available. Various DC voltages exist between the rails, particularly 270 volts DC and 540 volts DC. With this described energy supply concept, different voltages can be supplied to the motors in the spinning machine, allowing them to operate with very high efficiency. In particular, 540 volts DC can be supplied to motors driving various functional units in the spinning machine (e.g., drafting rollers or ring spinning machine lift drives). In particular, other motors (such as those provided to drive spindles) can operate at 270 volts DC. Other motors remain connected to the AC voltage grid, such as 400 volts DC. For example, these motors drive doffing machines or suction systems. Higher-level controllers are connected to the 540 volt DC voltage grid at 24 volts DC via voltage converters.

[0003] In the event of a power grid failure or significant voltage drop, the corresponding speed setting is reduced and transmitted to all drives via the bus. Motors connected to the bus enter generator mode, in which the energy stored in the rotating mass is converted into electrical energy due to the reduced speed and fed to all electrical devices in a common intermediate circuit.

[0004] Under asymmetrical load conditions, there is a problem, for example, when a single spindle is not operating or when there is a voltage drop. When the voltage drops, the current increases, and there is a risk that the power supply may become insufficient. This is something to prevent. Summary of the Invention

[0005] Therefore, the object of this invention is to provide a consistent voltage for all electrical devices.

[0006] This objective is achieved by a spinning machine having the features of claim 1.

[0007] According to the invention, a spinning machine has multiple workstations, each equipped with an electric drive, particularly a DC motor. At least two DC voltage sources for voltages U1 and U2 each form DC voltage networks N1 and N2. At least three DC voltage rails are connected to at least two DC voltage sources to power the multiple drives (particularly DC motors). A first DC voltage rail is connected to a first DC voltage source, a second DC voltage rail is connected to a second DC voltage source, and a third DC voltage rail is operatively connected to both the first and second DC voltage sources. The two DC voltage networks N1 and N2 are preferably polarized differently, for example, such that a voltage U1 of +270 volts exists in DC voltage network N1, and a voltage U2 of -270 volts exists in DC voltage network N2. Current collectors for the multiple drives (particularly DC motors) are optionally connected to the first and third DC voltage rails, or to the second and third DC voltage rails. The two DC voltage networks N1 and N2 are electrically operatively connected to a voltage equalization device to compensate for the voltage difference between the two DC voltage networks N1 and N2. The voltage equalization device ensures that even if a voltage drop occurs in the DC voltage network, or if a single electrical appliance (e.g., a spindle) is not operating, for example, due to maintenance, there is essentially the same amount of voltage in the two DC voltage networks N1 and N2. Therefore, the voltage equalization device increases the voltage in the DC voltage network with the lower voltage by drawing energy from the other DC voltage network with the higher voltage. This energy transfer continues until the difference between the two voltage levels approaches zero. The sum of the voltages in the two DC voltage networks N1 and N2 remains essentially constant. Therefore, asymmetrical loads on DC voltage networks N1 and N2 do not occur.

[0008] It is particularly advantageous if the frequency converters act as voltage equalizers distributed to each of the DC voltage networks N1 and N2, and the frequency converters are connected to the isolation transformers on the output side. The two frequency converters and the isolation transformers compensate for the unbalanced voltages U1 and U2 in the two DC voltage networks N1 and N2. The corresponding outputs of the frequency converters are connected to the output side of the isolation transformer instead of the motor cables. This allows the two voltages U1 and U2 to be balanced. If one of the two voltages becomes too high, the voltage equalizer transfers energy from U1 to U2, and vice versa. This creates a floating center point with approximately the same voltage in the two intermediate circuits. Voltage U1 is applied to one of the frequency converters, while voltage U2 is applied to the other. The voltage equalizers regulate differently. The higher voltage decreases, while the lower voltage increases. Alternatively, the higher voltage decreases, while the lower voltage increases by the same amount. Therefore, the sum of U1 and U2 remains constant.

[0009] It is also advantageous if the spinning machine has workstations with DC motors on both sides, and a DC voltage network N1 or N2 is allocated to each workstation or drive (especially the DC motor) on one side. A spinning machine with workstations with drives (especially DC motors) arranged on both longitudinal sides is particularly efficient in terms of its space requirements within the spinning mill. Ring spinning machines are typically designed as double-sided spinning machines. However, other spinning machines exist, such as some air-jet spinning machines, which are designed as single-sided spinning machines. The invention is also applicable to such spinning machines. According to the invention, in a particularly advantageous embodiment, the two DC voltage networks of the spinning machine can be arranged such that DC voltage network N1 is allocated to the workstation on one side of the machine, while DC voltage network N2 is allocated to the workstation on the other side of the machine. Voltage equalization occurs between the two sides of the machine. This is advantageous if different yarns are spun on the two sides of the machine, and different maintenance cycles (e.g., changing bobbins) are performed accordingly. The load on the two sides of the machine thus varies over time. Therefore, balancing the two DC voltage networks N1 and N2 is advantageous in terms of consistency.

[0010] It is particularly advantageous to divide the spinning machine into sections, with multiple workstations arranged in each section; and in each case, to alternately distribute DC voltage networks N1 or N2 to adjacent sections. Most known spinning machines are divided into sections. Several workstations are grouped together according to their arrangement on the spinning machine. These workstations in the corresponding sections can also operate jointly in terms of power supply and control. Spinning machines typically have multiple sections. For example, in each section, 24 workstations are combined on each side of the machine. According to an advantageous embodiment of the invention, if DC voltage networks N1 and N2 are alternately fed to adjacent sections, positive and negative DC voltages U1 or U2 are alternately applied to the motors of the workstations in the corresponding sections along the longitudinal direction of the spinning machine. Thus, in terms of voltage supply, the spinning machine is divided in the longitudinal direction. Therefore, uneven operation of the motors in the various workstations of the sections can be compensated for in terms of power supply.

[0011] It is also advantageous if the spinning machine has workstations on both sides and is further divided into sections, with multiple workstations arranged in each section, and DC voltage networks N1 and N2 are alternately distributed to opposite sides and adjacent sections. In this particularly advantageous embodiment, not only is there an alternation in adjacent sections, but the workstations on opposite sides of the machine within a section are also connected to different DC voltage networks N1 and N2. This makes the different voltages that may occur in the various workstations more balanced. Therefore, the spinning machine can operate in a more balanced manner with respect to its voltage supply.

[0012] It is particularly advantageous to connect additional drives (especially DC motors) to the first and second DC voltage rails. By connecting additional drives to the first and second DC voltage rails, the drives (especially DC motors) can operate on the spinning machine at a different voltage U3. Therefore, optimized power supply for the motors can be achieved according to the motor's task in the spinning machine. For example, motors of the same type gripping the first and third, or second and third DC voltage rails, can operate at 270 volts, while these additional drives connected to the first and second DC voltage rails can operate at U3 = 540 volts. For example, these drives (especially DC motors) operating at higher voltages can be used for drafting systems and lifting devices, while motors optimized for lower voltage operation can be used for spindle drives.

[0013] It is also advantageous if at least one inverter with at least one AC motor and / or a DC voltage transformer for an additional voltage U4 are arranged on both sides of the DC voltage rail. In addition to supplying the DC motor, the voltage supply also allows for the supply of AC voltage to the AC motor. Alternatively or additionally, a DC voltage transformer can be provided for an additional DC voltage. This is possible due to the advantageous arrangement of the inverter and / or the DC voltage transformer on both sides of the DC voltage rail. For example, the AC motor can be used in a doffing machine to change bobbins or for suction in a spinning machine. For example, the additional DC voltage of the DC voltage transformer could be 24 volts and could be used to power the machine's controller.

[0014] If the isolation transformer is a high-frequency transformer, it is particularly advantageous. High-frequency transformers have the advantages of high conversion efficiency and small size.

[0015] It is also advantageous if the frequency converter has a braking resistor to limit voltage peaks. Overvoltages from the DC voltage grid N1 or N2 are reduced via the braking resistor. This ensures the safety of the entire system.

[0016] Furthermore, it is advantageous if the two DC voltage rails N1 and N2 have symmetrical resistors to obtain the base levels of DC voltage rails N1 and N2. Providing symmetrical resistors to compensate for the base levels prevents intermediate circuit drift, for example, when the machine is turned on. This reduces voltage peaks. Electrolytic capacitors are arranged in series between two of the three DC voltage rails to distribute the voltage. To ensure uniform voltage distribution, symmetrical resistors are connected in parallel and also in series with the electrolytic capacitors.

[0017] It is also advantageous if the two DC voltage grids N1 and N2 are polarized in opposite directions. To power the machine, positive and negative voltages alternate, for example, U1 = +270 volts and U2 = -270 volts. This ensures, for example, that if a fault occurs on one side of the machine, a constant average voltage remains and a floating neutral point can be maintained.

[0018] The spinning machine is designed according to the above description, and the mentioned features may exist individually or in any combination.

[0019] In addition to the DC motors described above, or other DC motors described above, AC motors connected to the DC voltage rail via an inverter can also be used. Attached Figure Description

[0020] Further advantages of the invention are described in the following embodiments. In the accompanying drawings:

[0021] Figure 1 This is a voltage supply diagram according to the invention for use in spinning machines.

[0022] Figure 2This is a diagram of a voltage equalization device.

[0023] Figure 3 It is a diagram showing the alternative voltage distribution in a spinning machine, and

[0024] Figure 4 This is another alternative voltage distribution diagram in a spinning machine. Detailed Implementation

[0025] In the following description of the alternative embodiments shown, the same reference numerals are used for features that are identical in design and / or operating mode to those shown in the other figures. Unless otherwise stated, the design and / or operating mode of these features correspond to the design and / or operating mode of features described elsewhere. For clarity, in some cases, reference numerals are used only for similar components.

[0026] Figure 1 This is a voltage supply diagram according to the invention for a spinning machine, such as a ring spinning machine, an air-jet spinning machine, or a rotor spinning machine.

[0027] The spinning machine is connected to a primary three-phase AC voltage source 1, for example, each with 400 volts. A 540-volt DC voltage U3 is generated in the DC grid N3 via a feeder unit 2. On the output side of the feeder unit 2, a first DC voltage rail 3 is arranged on the first DC voltage source 2.1 and a second DC voltage rail 4 is arranged on the second DC voltage source 2.2. Two electrolytic capacitors 5 and 6 are connected in series between the two DC voltage rails 3 and 4. A third DC voltage rail 7, located between the two electrolytic capacitors 5 and 6, divides the voltage U3 between the two DC voltage rails 3 and 4. Thus, a voltage U1 = +270 volts is applied in the first DC voltage grid N1 between the first DC voltage rail 3 and the third DC voltage rail 7. A voltage also exists between the second DC voltage rail 4 and the third DC voltage rail 7, where U2 = -270 volts is present in the second DC voltage grid N2. The purpose is to ensure that the two 270-volt voltages are substantially the same in magnitude and that there is no uneven voltage in the two DC voltage grids N1 and N2, even with an unbalanced load, thereby maintaining the same basic level. Therefore, the two symmetrical resistors 8 and 9, which are connected in series, are arranged in parallel with the two electrolytic capacitors 5 and 6.

[0028] A third DC voltage grid N3 with 540 volts is applied between the first DC voltage rail 3 and the second DC voltage rail 4. Electrical equipment that is more efficient at higher voltages is connected to this DC voltage grid N3. For this purpose, for example, a DC motor 10 can be provided for the drafting system of a spinning machine and for lifting devices for the ring rail or spindle rail. Another DC motor 11 can be used, for example, for the machine's suction device. Each motor is protected by fuses 12 and 13. Further protection against overload of the DC voltage grid N3 is provided by a thermal switch 14, which disconnects the two DC voltage rails 3 and 4 in the DC voltage grid N3 from the voltage supply in the event of overheating.

[0029] DC voltage transformer 15 is arranged in another line of the two DC voltage rails 3 and 4 of the DC voltage network N3. DC voltage transformer 15 converts 540 volts DC voltage to 24 volts DC voltage. This lower 24 volts DC voltage is available via fuse 16, for example, for machine control purposes. An inverter for connection to an AC motor may also be provided in addition to DC voltage transformer 15 or in addition to DC voltage transformer 15.

[0030] Thermal switch 17 also protects the two DC voltage networks N1 and N2 from thermal overload. A positive voltage U1 = +270 volts exists in the first DC voltage network N1, while a negative voltage U2 = -270 volts exists in the second DC voltage network N2. To keep the two DC voltage networks N1 and N2 at essentially the same voltage level, even when using electrical equipment with different loads, voltage equalization device 18 is connected to the three DC voltage rails 3, 4, and 7. Voltage equalization device 18 will... Figure 2 A more detailed description is provided below.

[0031] Multiple DC motors 19 for the spindle drive of a spinning machine are connected to two DC voltage grids N1 and N2. Alternatively, or in addition to the DC motors 19, AC motors connected to DC voltage rails 3, 4, and 7 can also be used with an inverter.

[0032] Voltage is supplied via connection element 20 and DC voltage bus 21. DC voltage bus 21 is used to distribute the voltage supply to the DC motors 19 along the spinning machine. The spinning machine has two sides 22 and 23. Multiple sections 24' to 24n are provided on each side 22 and 23. Spindles or DC motors 19 are grouped in individual sections 24' to 24n. For example, ten spindles and DC motors 19 may be provided per section 24, 24' to 24n.

[0033] As from Figure 1As shown in the diagram, DC voltage networks N1 and N2, with voltages U1 and U2, are alternately distributed on machine side 22 from segment 24' to segment 24m. Similarly, on the other machine side 23, DC voltage networks N1 and N2 are alternately supplied with voltages U1 and U2 to each segment 24'' to segment 24n. Additionally, the opposing segments 24' and 24'' to segments 24m and 24n are alternately distributed to DC voltage networks N1 and N2 with voltages U1 and U2. A significant advantage of this is that DC voltage networks N1 and N2 will bear substantially uniform loads. Events occurring on a single DC motor 19 and causing voltage drops must be frequently distributed to a single machine side 22 or 23. Accordingly, even if, for example, one machine side 22 or 23 fails, the other machine side 23 or 22 utilizes both DC voltage networks N1 and N2 evenly. This essentially prevents voltage spikes in one of the DC voltage networks N1 or N2.

[0034] Figure 2 A diagram showing a more detailed explanation of the voltage equalization device 18 is provided. The voltage equalization device 18 is connected to two DC voltage networks N1 and N2. (As shown from...) Figure 1 As can be seen, the DC voltage grid N1, with a positive voltage U1 = +270 volts, is located between the first DC voltage rail 3 and the third DC voltage rail 7. The second DC voltage grid N2, with a negative voltage U2 = -270 volts, is located between the second DC voltage rail 4 and the third DC voltage rail 7. The 540 volt voltage between DC voltage rail 3 and the second DC voltage rail 4 is correspondingly divided by two capacitors 5 and 6. Symmetrical resistors 8 and 9 ensure that the divided voltage is symmetrical.

[0035] The voltage equalization device 18 has two frequency converters 25 and 26. On the output side, the two frequency converters 25 and 26 are connected to a high-frequency isolation transformer 27. To prevent overload of the two frequency converters 25 and 26, braking resistors 28 and 29 are distributed to each of the frequency converters 25 and 26. This compensates for the two voltages U1 and U2 of the two DC voltage networks N1 and N2. If one of the two voltages U1 or U2 is higher than the other voltage U2 or U1, the voltage is reduced and the other voltage is increased. This balances the two voltages, allowing the spinning machine to operate in a very stable manner.

[0036] Figure 3 A diagram showing the alternative load distribution in a spinning machine is presented. Based on... Figure 1 In the voltage distribution, the voltage distribution in a single segment 24' to 24n alternates with respect to DC voltage grids N1 and N2 or voltages U1 and U2; and according to Figure 3In this embodiment, the voltage distribution is alternately allocated to the workstations or sections 24' to 24n on both sides 22 and 23 of the spinning machine. Therefore, sections 24' to 24m are connected to a DC voltage network N2 with a voltage U2 = -270 volts. Sections 24'' to 24n are supplied with a voltage U1 = +270 volts from DC voltage network N1. Such a voltage distribution is advantageous if it can be assumed that different loads are expected on both sides 22 and 23, which would result in voltage fluctuations applied to the two DC voltage networks N1 and N2 and must be compensated for by the voltage equalization device 18.

[0037] Figure 4 This is an alternative load distribution diagram for the spinning machine. Here, opposite sections 24' to 24n have the same voltages U1 and U2. Correspondingly, sections 24' and 24'' are connected to a DC voltage network N1 with voltage U1 = +270 volts. Adjacent sections 24m and 24n are connected to a DC voltage network N2 with voltage U2 = -270 volts. Similar to... Figure 1 The load distribution is alternating, occurring within a single segment 24' to 24n. However, opposing segments 24' to 24n are connected to the same DC voltage grid N1 or N2. This has the same characteristics as those from... Figure 1 It has similar advantages to voltage distribution, but offers additional advantages in terms of wiring for spinning machines.

[0038] This invention is not limited to the embodiments shown and described. Modifications within the scope of the claims are possible, and combinations of features are also possible, even if these features are shown and described in different embodiments.

[0039] List of reference numerals

[0040] 1 AC voltage source

[0041] 2. Power supply unit

[0042] 2.1 First DC Voltage Source

[0043] 2.2 Second DC Voltage Source

[0044] 3 First DC voltage rail

[0045] 4. Second DC voltage rail

[0046] 5. Electrolytic capacitors

[0047] 6. Electrolytic capacitors

[0048] 7 Third DC voltage rail

[0049] 8 Symmetrical Resistors

[0050] 9 Symmetrical Resistors

[0051] 10 DC motors

[0052] 11 DC motors

[0053] 12. Fuse

[0054] 13. Fuse

[0055] 14 Thermal switch

[0056] 15 DC voltage transformers

[0057] 16. Fuse

[0058] 17 Thermal Switch

[0059] 18. Voltage equalization device

[0060] 19 DC motors

[0061] 20 Connecting elements

[0062] 21 DC bus

[0063] 22. Side of the machine

[0064] 23. The side of the machine

[0065] 24 sections

[0066] 25. Frequency converter

[0067] 26. Frequency converter

[0068] 27 High-frequency isolation transformer

[0069] 28 Braking Resistor

[0070] 29 Braking Resistor

[0071] U1 voltage

[0072] U2 voltage

[0073] U3 voltage

[0074] U4 voltage

[0075] N1 DC voltage network

[0076] N2 DC voltage network

[0077] N3 DC voltage grid.

Claims

1. A spinning machine, - It has multiple workstations, which are equipped with electric drives, specifically DC motors (10, 11, 19). - Equipped with at least two DC voltage sources (2.1, 2.2), wherein the at least two DC voltage sources (2.1, 2.2) have voltages U1 and U2, - Each of the at least two DC voltage sources (2.1, 2.2) forms a DC voltage network N1 and N2. - Wherein at least three DC voltage rails (3, 4, 7) for powering multiple drives, particularly the DC motors (10, 11, 19), are connected to the at least two DC voltage sources (2.1, 2.2) in the following manner: o The connection between the first DC voltage rail (3) and the first DC voltage source (2.1) for operation. o The connection between the second DC voltage rail (4) and the second DC voltage source (2.2) for operation, and o The connection between the third DC voltage rail (7) and the first DC voltage source (2.1) and the second DC voltage source (2.2) for operation. - and wherein the current collectors of a plurality of said drives are optionally connected to the first DC voltage rail (3) and the third DC voltage rail (7), or connected to the second DC voltage rail (4) and the third DC voltage rail (7), said drives, in particular said DC motor (19), are characterized in that, Two DC voltage networks N1 and N2 are operatively connected to a voltage equalization device (18) to compensate for the voltage difference in the two DC voltage networks N1 and N2.

2. The spinning machine according to the preceding claims, characterized in that, The frequency converters (25, 26) are distributed to each of the DC voltage networks N1 and N2 as the voltage equalization device (18), and the frequency converters (25, 26) are connected to the isolation transformer (27) on the output side.

3. The spinning machine according to one or more of the preceding claims, characterized in that, The spinning machine has workstations on both sides, and a DC voltage network N1 or N2 is distributed to the workstation on one side (22, 23).

4. The spinning machine according to one or more of the preceding claims, characterized in that, The spinning machine is divided into sections (24' to 24n), each of which is equipped with multiple workstations, and a DC voltage network N1 or N2 is alternately distributed to the adjacent sections (24' to 24n).

5. The spinning machine according to one or more of the preceding claims, characterized in that, The spinning machine has workstations on both sides and is further divided into sections (24' to 24n), each of which has multiple workstations arranged, and a DC voltage network N1 and N2 are alternately distributed to the opposite side (22, 23) and the adjacent section (24' to 24n).

6. The spinning machine according to one or more of the preceding claims, characterized in that, Additional drives, particularly DC motors (10, 11), are connected to the first DC voltage rail (3) and the second DC voltage rail (4).

7. The spinning machine according to one or more of the preceding claims, characterized in that, At least one inverter with at least one AC motor and / or a DC voltage transformer (15) for an additional voltage U4 are arranged on both of the DC voltage rails (3, 4, 7).

8. The spinning machine according to one or more of the preceding claims, characterized in that, The isolation transformer (27) is a high-frequency transformer.

9. The spinning machine according to one or more of the preceding claims, characterized in that, The frequency converters (25, 26) have braking resistors (28, 29) to limit voltage peaks.

10. The spinning machine according to one or more of the preceding claims, characterized in that, The two DC voltage networks N1 and N2 have symmetrical resistors (8, 9) to obtain the basic levels of the DC voltage networks N1 and N2.

11. The spinning machine according to one or more of the preceding claims, characterized in that, The two DC voltage networks N1 and N2 are polarized in opposite directions.

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