Plant for brush manufacturing and use of a feed-in / return converter for operating a plant for brush manufacturing

Abstract

A brush manufacturing system with an AC voltage connection (2) and several electrical devices, characterized in that the system (1) has a first DC intermediate circuit (4) with a first DC voltage (VDC1) and a second DC intermediate circuit (5) with a second DC voltage (VDC2), wherein the first DC voltage (VDC1) is greater than the second DC voltage (VDC2), and that at least one electrical device is operated on the first DC intermediate circuit (4) and at least one electrical device is operated on the second DC intermediate circuit (5).

Description

[0001] The invention relates to a system for brush manufacturing with several electrical operating devices.

[0002] A brush manufacturing plant can comprise one or more brush machines. These typically have several functional units, such as a dividing disc, a tamping unit, an injection molding machine, a heating system, conveyors, and other components, which can vary depending on the type of brushes being produced. Each of these functional units can include several electrical components, such as drive motors, actuators, controllers, and sensors. The individual electrical components can operate independently of their assignment to a specific functional unit.

[0003] The system typically operates on a three-phase AC power grid (three-phase network), connected to the grid via an isolation transformer. The isolation transformer can be designed for various input AC voltages and generate an operating AC voltage that is independent of the input AC voltage. Furthermore, the system is galvanically isolated from the grid.

[0004] The electrical equipment is usually operated at the operating AC voltage, whereby any other operating voltage that may be required is generated by the equipment itself or an associated voltage converter.

[0005] However, this can lead to high distortion reactive power in the system, which is converted into heat in the isolation transformer. This means that the energy drawn from the grid is greater than would actually be needed.

[0006] The object of the invention is to create a system of the aforementioned type that can be operated more energy-efficiently.

[0007] This problem is solved by a system with the features of claim 1.

[0008] According to the invention, the system comprises a first DC intermediate circuit with a first DC voltage and a second DC intermediate circuit with a second DC voltage, wherein the first DC voltage is greater than the second DC voltage. According to the invention, at least one electrical device is operated on the first DC intermediate circuit and at least one electrical device is operated on the second DC intermediate circuit.

[0009] The advantage is that an isolation transformer is no longer needed to provide an operating AC voltage and can be completely omitted.

[0010] Within the individual electrical devices, rectifiers and / or voltage converters are no longer necessary, resulting in less power loss and reduced heat generation. The elimination of certain components also enables more cost-effective manufacturing and installation of the system.

[0011] This results in significantly lower heat losses, which in turn allows for a reduction in control cabinet temperature. The reduced heat generation also enables a longer service life for the electrical components.

[0012] Another advantage is that there is less wiring effort required, and smaller conductor cross-sections are possible due to the lower apparent and / or reactive power.

[0013] This results in overall energy savings through improved efficiency and increased efficiency, as well as cost savings.

[0014] In one configuration, the system has an AC voltage connection and an active infeed converter (AIC) connected to the AC voltage connection, which provides the first DC voltage for the first DC intermediate circuit. The system also has a DC-DC converter that provides the second DC voltage for the second DC intermediate circuit.

[0015] The AIC has a compact design and is significantly smaller than a transformer of the same power rating. The system, at least the power supply, can therefore be designed more compactly and also more cost-effectively.

[0016] Another advantage of an AIC is its ability to feed back into the grid. This can, for example, eliminate the need for a braking chopper. It also facilitates the integration of a photovoltaic system into a building, as the AIC allows excess solar power to be fed back into the grid.

[0017] The entire system forms a DC intermediate circuit. Within this circuit, regenerative energy generated at one point can be used by power supplies and other electrical equipment within the same or even a different DC intermediate circuit.

[0018] Another advantage is that the AIC can compensate for voltage fluctuations, such as those caused by inrush currents in soft networks or general voltage fluctuations.

[0019] Short network interruptions can be buffered by a high DC link capacity.

[0020] A brush manufacturing plant typically has many electrical components that are arranged and operated side by side. Therefore, it is particularly advantageous if all these electrical components are each operated on one of the two DC intermediate circuits. In this way, a significant increase in electrical efficiency can be achieved.

[0021] It is also possible to combine several plants into a kind of micro-grid and operate them on a single AIC. Thus, one AIC may suffice for large plants or multiple interconnected plants.

[0022] In one design, the DC-DC converter is connected to the first DC voltage as its input voltage. In this way, the second DC voltage is generated from the first. This has the advantage that the DC-DC converter can be designed to be very efficient.

[0023] It is particularly advantageous if the DC-DC converter for generating the second DC voltage is located inside the AIC.

[0024] In one version, the AIC features an active power factor correction (PFC) unit. This compensates for any reactive power that may occur, ensuring that the AIC only draws active power from the AC grid. This power factor correction guarantees trouble-free operation.

[0025] In one embodiment, the AIC features a voltage boost converter for generating the initial DC voltage, either as an alternative or in addition to the PFC. This initial DC voltage is higher than the input AC voltage. This allows the DC voltage in the intermediate circuit to be higher than the AC voltage supplied by the mains. This, for example, permits higher motor speeds in motors with voltage-dependent speed. It can also reduce current at the same power output, thus enabling the use of smaller conductor cross-sections.

[0026] In a brush stuffing machine with a separating plate, the maximum speed depends, for example, on the maximum rotational speed. The higher voltage allows for a higher rotational speed and therefore a faster stuffing process.

[0027] In one version, the first DC voltage is between 600 VDC and 800 VDC, in particular 750 VDC.

[0028] In one version, the input AC voltage is between 220 VAC and 480 VAC. The input AC voltage can also be a three-phase AC voltage, particularly three-phase current.

[0029] In one version, the second DC voltage is a low voltage. For example, the second DC voltage is between 20VDC and 50VDC, particularly 24VDC.

[0030] In one embodiment, the system has at least one frequency-controlled drive as an electrical operating device, which is operated via a frequency converter on the first DC intermediate circuit, in particular wherein the frequency converter is assigned to one frequency-controlled drive or several frequency-controlled drives.

[0031] The frequency converter can be a DC / AC converter, which eliminates the need for an internal rectifier compared to a normally required AC / AC converter.

[0032] It is also possible to operate several identical frequency-controlled drives on one frequency converter.

[0033] In one embodiment, the system has at least one servo drive as an electrical operating device, which is operated via a servo controller on the first DC intermediate circuit, in particular wherein the servo controller is assigned to one servo drive or several servo drives.

[0034] Here too, a rectifier that would otherwise be necessary in the servo controller can be omitted, which increases efficiency and reduces power loss.

[0035] In one configuration, the system includes at least one lighting unit and / or at least one programmable logic controller and / or low-voltage drives as electrical equipment, which are operated on the second DC intermediate circuit. In this way, a common second DC voltage is available, so that individual power supplies for the individual electrical equipment can be eliminated.

[0036] In addition to the aforementioned electrical equipment, numerous other components and electrical equipment can be operated on the first DC intermediate circuit and / or the second DC intermediate circuit.

[0037] The invention also includes the use of an active-infeed converter (AIC) for operating a brush manufacturing plant, characterized in that the AIC is connected to an operating AC voltage and the AIC provides a first DC voltage for a first DC intermediate circuit and a second DC voltage for a second DC intermediate circuit, and that at least one electrical device of the plant is operated on the first DC intermediate circuit and at least one electrical device of the plant is operated on the second DC intermediate circuit.

[0038] In one configuration, every electrical device in the system is operated on one of the two DC intermediate circuits. This means that no electrical device within the system has a direct connection to the AC mains voltage. The advantage of this is that an AIC with power factor correction achieves maximum possible efficiency, since all power is fed back to the AIC and can be balanced there by the PFC.

[0039] The invention is explained in more detail below with reference to an exemplary embodiment and the accompanying drawings.

[0040] It shows: Fig. 1: a symbolic representation of a brush machine with a DC power supply, Fig. 2: a schematic block diagram of a brush manufacturing plant with a feed-in / regenerative converter and two DC intermediate circuits, and Fig. 3: a schematic block diagram of the feed-in / feed-back converter of the Fig. 1.

[0041] The Fig. Figure 2 shows a schematic block diagram of a brush manufacturing system 1 according to the invention. The system has an AC voltage connection 2 for connecting the system 1 to a mains AC voltage VAC. This mains AC voltage VAC is generally a three-phase AC voltage, or three-phase current, and is between 220 VAC and 480 VAC.

[0042] The system also includes an active infeed converter (AIC) which is connected to the AC voltage connection 2.

[0043] The AIC 3 provides on the output side a first DC intermediate circuit 4 with a first DC voltage VDC1 and a second DC intermediate circuit 5 with a second DC voltage VDC2.

[0044] In this example, the first DC voltage VDC1 of the first DC intermediate circuit 4 is 750 volts, the second DC voltage VDC2 of the second DC intermediate circuit 5 is 24 volts.

[0045] The system includes at least one servo drive 6 as an electrical component, which is operated via a servo controller 7 on the first DC intermediate circuit 4. The servo controller 7 can be assigned to one or more servo drives 6.

[0046] The system 1 includes at least one frequency-controlled drive 8 as electrical equipment, which is operated via a frequency converter 9 on the first DC intermediate circuit 4. The frequency converter 9 can be assigned to one or more frequency-controlled drives 8. The frequency converter 9 is designed as a DC / AC converter to generate an AC voltage for the frequency-controlled drive 8 from the first DC voltage VDC1.

[0047] The system 1 further comprises at least one system lighting 11 and / or at least one programmable logic controller 10 and / or low-voltage drives 12 as electrical equipment, which are operated on the second DC intermediate circuit 5. These small loads thus do not require rectifiers but possibly only a voltage regulator, which can be operated directly with the second DC voltage VDC2.

[0048] The system can, in one configuration, also include one or more three-phase synchronous motors 13, which are operated directly on the AC mains voltage VAC. The three-phase synchronous motor 13 is in the Fig. 1. Shown by dotted lines to illustrate the separate execution.

[0049] The Fig. Figure 3 shows a block diagram of the AIC 3. Fig.2. The AIC 3 has an AC voltage input 2, a first DC voltage output 14, and a second DC voltage output 15. The AIC has a voltage boost converter 16, which generates a first DC voltage VDC1 from the input AC voltage and provides it at the first DC voltage output 14. The voltage boost converter 16 may include an active rectifier stage. This first DC voltage VDC1 can be higher than the input AC voltage, for example, in the range between 600 VDC and 800 VDC. The AIC further has a DC-DC converter 17, which is internally connected to the first DC voltage VDC1 and generates a second DC voltage VDC2 from it, which is lower than the first DC voltage VDC1. The second DC voltage VDC2 is preferably a low voltage, for example, in the range between 18 VDC and 30 VDC.

[0050] Furthermore, the AIC 3 features an active power factor correction (PFC). This PFC can virtually eliminate distortion reactive power that arises in the two DC intermediate circuits.

[0051] Plant 1 can therefore be operated much more energy-efficiently. A transformer can be omitted, making the plant more compact and also more cost-effective. Reference symbol list 1 Annex 2 AC voltage connections 3 feed-in to regenerative converters, AIC 4 first DC intermediate circuit 5 second DC intermediate circuit 6 servo drive 7 servo controllers 8 frequency-controlled drives 9 frequency converters 10 programmable logic controllers 11 Plant lighting 12 low-voltage drives 13 three-phase synchronous motors 14 first DC output 15 second DC output 16 voltage boost converters 17 DC / DC converters 18 Power Factor Correction (PFC) AC mains voltage VDC1 first DC voltage VDC2 second DC voltage

Claims

[1] Brush manufacturing plant with multiple electrical equipment, characterized by , that the system (1) has a first DC intermediate circuit (4) with a first DC voltage (VDC1) and a second DC intermediate circuit (5) with a second DC voltage (VDC2), wherein the first DC voltage (VDC1) is greater than the second DC voltage (VDC2), and that at least one electrical device is operated on the first DC intermediate circuit (4) and at least one electrical device is operated on the second DC intermediate circuit (5). [2] Plant according to claim 1, characterized by, that the system (1) has an AC voltage connection (2) and an active-infeed converter (3), AIC (Active-Infeed-Converter) connected to the AC voltage connection (2) and providing the first DC voltage (VDC1) for the first DC intermediate circuit (4) and that the system (1) has a DC voltage converter (17) providing the second DC voltage (VDC2) for the second DC intermediate circuit (5). [3] Plant according to claim 2, characterized by , that the DC-DC converter (17) is connected to the first DC voltage (VDC1) as the input voltage and generates the second DC voltage (VDC2) from the first DC voltage (VDC1), in particular wherein the DC-DC converter (17) is arranged inside the AIC (3). [4] Plant according to claim 2 or 3, characterized by, that the AIC (3) has an active power factor correction (PFC) unit (18), and / or that the AIC (3) has a voltage boost converter (16) for generating the first DC voltage (VDC1), wherein the first DC voltage (VDC1) is greater than the input AC voltage (VAC). [5] Plant according to any of the preceding claims, characterized by , that the second DC voltage (VDC2) is a low voltage and / or that the first DC voltage (VDC1) is between 600VDC and 800VDC, in particular 750VDC and / or that the second DC voltage (VDC2) is between 20VDC and 50VDC, in particular 24VDC, and / or that the input AC voltage is between 220VAC and 480VAC, in particular wherein the input AC voltage (VAC) is a three-phase AC voltage. [6] Plant according to any of the preceding claims, characterized by, that the system (1) has at least one frequency-controlled drive (8) as electrical equipment which is operated via a frequency converter (9) on the first DC intermediate circuit (4), in particular wherein the frequency converter (9) is assigned to the one frequency-controlled drive (8) or several frequency-controlled drives. [7] Plant according to any of the preceding claims, characterized by that the system has at least one servo drive (6) as an electrical operating device which is operated via a servo controller (7) on the first DC intermediate circuit (4), in particular wherein the servo controller (7) is assigned to one servo drive (6) or several servo drives. [8] Plant according to any of the preceding claims, characterized by, that the installation (1) has at least one installation lighting (11) and / or at least one programmable logic controller (10) and / or low-voltage drives (12) as electrical equipment which are operated on the second DC intermediate circuit (5). [9] Use of an active infeed converter (3) AIC (Active-Infeed-Converter) for operating a brush manufacturing plant (1), characterized by , that the AIC (3) is connected to an operating AC voltage (VAC) and the AIC (3) provides a first DC voltage (VDC1) for a first DC intermediate circuit (4) and a second DC voltage (VDC2) for a second DC intermediate circuit (5), and that at least one electrical device of the installation is operated on the first DC intermediate circuit (4) and at least one electrical device of the installation (1) is operated on the second DC intermediate circuit (5). [10] Use according to claim 9, characterized by, that each electrical device of the system (1) is operated on one of the two DC intermediate circuits (4, 5).

Images