System with synchronous linear motor and method for operating a system

Abstract

A system with synchronous linear motor and method for operating a system, wherein a mobile part is movably arranged along a conveying path and stator windings of the synchronous linear motor are arranged along the conveying path, wherein the mobile part has a permanent magnet arrangement, the permanent magnets of which are operatively connected to the stator windings, wherein the respective stator winding is electrically fed from the AC voltage-side connection of a respective inverter, wherein the DC voltage-side connections of the inverters are connected in parallel to one another and to a first series circuit formed from a resistor R and two first controllable switches, wherein a second series circuit can be connected in parallel to the series circuit, which second series circuit has at least one energy store and a controllable switch.

Description

[0001] System with synchronous linear motor and method for operating a system

[0002] Description:

[0003] The invention relates to a system with a synchronous linear motor and a method for operating a system.

[0004] It is generally known that a synchronous motor has permanent magnets arranged so that they can be moved relative to the stator winding of the synchronous motor.

[0005] The invention is therefore based on the objective of designing and safely operating a synchronous motor.

[0006] According to the invention, the problem is solved in the system with synchronous linear motor according to the features specified in claim 1 and in the method according to the features specified in claim 13.

[0007] Key features of the invention in the system with synchronous linear motor are that a mobile unit is movably arranged along a conveyor path and stator windings of the synchronous linear motor are arranged along the conveyor path, wherein the mobile unit has a permanent magnet arrangement whose permanent magnets are in operative connection with the stator windings, wherein the respective stator winding is electrically supplied from the AC-side connection of a respective inverter, wherein the DC-side connections of the inverters are connected in parallel to each other and to a first series circuit, which is formed from a resistor R and two first controllable switches, wherein a second series circuit can be connected in parallel to the series circuit, which has at least one energy storage device and one controllable switch.

[0008] ISI \ EIDOPAT 10.11.2025 A key advantage is that braking is simple and safe to implement. This is because only one resistor or resistor array is needed for all inverters. Depending on the position of the mobile device, different inverters generate regenerative energy, meaning that the current to be converted into heat by the resistor is generated by different inverters over time.

[0009] Furthermore, controlling the first controllable switches is safely feasible, since if one of the switches is welded shut, the other switch can still interrupt the current.

[0010] In an advantageous embodiment, the second series circuit additionally includes a fuse or another controllable switch. The advantage here is that safety is further increased. In particular, the use of an additional controllable switch provides further controllable safety, thus enabling redundant interruption of the current.

[0011] In an advantageous embodiment, the DC-side connection of an AC / DC converter, particularly a rectifier, is electrically connected in parallel to the series circuit. The advantage here is that the intermediate circuit thus formed can be supplied by the AC / DC converter, particularly the rectifier, and from this supply the inverters, which, however, exchange energy via the intermediate circuit during generator operation, which can be discharged through the resistor.

[0012] In an advantageous embodiment, a voltage converter is electrically supplied from the DC-side connection of the AC / DC converter, particularly the rectifier. This voltage converter can be supplied from a three-phase power supply network and also provides a low voltage, particularly 24 volts. A key advantage is that in the event of a power outage or if the DC link is disconnected from the AC / DC converter, the voltage converter can still be supplied from the DC link. This is significantly enhanced by the energy storage device.

[0013] In an advantageous embodiment, a third series circuit is connected in parallel to the series circuit. This third circuit comprises a second resistor R and two further controllable switches. The advantage here is that if the first series circuit fails, the third series circuit is available to maintain operation. In another advantageous embodiment, each first controllable switch comprises a first individual switch and a second individual switch mechanically coupled to the first individual switch for synchronous switching. The first resistor R is connected in series with the first individual switch of the first controllable switch and with the first individual switch of the second controllable switch. The advantage here is that the current loop passing through the second individual switches allows monitoring of the connection of the resistor R to the intermediate circuit.

[0014] In an advantageous embodiment, a series circuit formed from the second single switch of the first controllable switch and the second single switch of the second controllable switch makes two inputs of a safety controller electrically connectable. The advantage here is that monitoring the function of the first controllable switch can be carried out in a simple manner, thus ensuring safe operation.

[0015] In an advantageous embodiment, the second individual switches are open when the first individual switches are closed, and vice versa. It is advantageous that the respective first individual switch is mechanically coupled to the respective second individual switch, and therefore both individual switches of a given controllable switch are switched simultaneously.

[0016] In an advantageous embodiment, the permanent magnet assembly of the handset is always operatively connected to several stator windings. The advantage here is that the handset covers several stator windings, and thus the generator-produced current is driven by the respective stator windings it covers.

[0017] In an advantageous embodiment, the vertical projection of the permanent magnet arrangement of the handset into a horizontal plane includes the vertical projections of several stator windings into this horizontal plane. It is advantageous that not just one, but several stator windings supply a generator-generated current to the intermediate circuit, and that only one resistor or resistor arrangement is available for conversion, shared by all inverters. In an advantageous embodiment, the energy storage device comprises a DC / DC converter and a battery and / or double-layer capacitor, in particular an ultracapacitor, wherein the DC / DC converter is connected to the intermediate circuit via the second series connection at its first DC-side terminal and is electrically connected to the battery and / or double-layer capacitor, in particular an ultracapacitor, at its second DC-side terminal.An advantage of this is that the electrical power flow between the energy storage device and the energy storage unit can be controlled via the DC / DC converter. The DC / DC converter is designed to be suitable for this purpose.

[0018] In an advantageous embodiment, a first voltage converter can be supplied from the parallel connection of the DC-side terminals of the inverters. This first voltage converter provides a low voltage, in particular a supply voltage of 24 volts, to a control unit and / or the inverters. The first voltage converter can also be supplied from a three-phase power supply network, which feeds the AC-side terminal of the AC / DC converter, in particular the rectifier. An advantage of this configuration is that a stable supply to the control unit and other control electronics, such as the inverter control electronics, is ensured, since in the event of a failure of the three-phase power supply network, a backup supply from the intermediate circuit, which is buffered by the energy storage device, is also possible. Even with a depleted energy storage device, a supply in generator mode is still possible.

[0019] In an advantageous embodiment, a second voltage converter is connected in parallel to the first. The first voltage converter can be supplied from the parallel DC-side connections of the inverters, providing a low voltage, in particular a supply voltage of 24 volts, to a control unit and / or the inverters. The first voltage converter can also be supplied from a three-phase power supply network, which feeds the AC-side connection of the AC / DC converter, in particular the rectifier. An advantage of this configuration is the increased reliability, as the failure of one of the voltage converters allows the other to perform its function as a backup.Key features of the method for operating the aforementioned system are that, in a first step, the inverters are operated in controlled mode, with the controllable semiconductor switches of the inverters being controlled by pulse-width modulation, and an energy storage device being connected in parallel to the parallel DC-side connections of the inverters, and the DC-side connection of the AC / DC converter, in particular the rectifier, being connected in parallel to the parallel DC-side connections of the inverters. In a second step, a resistor R, particularly for discharging, is connected in parallel to the parallel DC-side connections of the inverters. An advantage of this method is that only one resistor is required for all inverters, thus minimizing the required effort.

[0020] In a preferred embodiment, controlled operation continues in the second process step, particularly as long as sufficient voltage is present. An advantage here is that safe braking with the highest possible braking force can be achieved.

[0021] In an advantageous embodiment, before the second process step, the energy storage device is disconnected from the DC-side connections of the inverters, and the DC-side connection of the AC / DC converter is also disconnected from the DC-side connections of the inverters. The advantage of this is that the resistor is protected from overload and as much energy as possible is retained, meaning that only excess energy is dissipated.

[0022] Further advantages arise from the dependent claims. The invention is not limited to the combination of features in the claims. For those skilled in the art, further meaningful combinations of claims and / or individual claim features and / or features of the description and / or the figures will become apparent, particularly from the problem statement and / or the problem arising from a comparison with the prior art. The invention will now be explained in more detail with reference to a schematic diagram.

[0023] Figure 1 shows the electrical circuit diagram of the stationary part of a synchronous linear motor according to the invention.

[0024] As shown in the figure, the synchronous linear motor has stator windings M arranged one behind the other along the conveyor path.

[0025] A mobile unit along this conveyor route, in particular a rail-guided unit, has a permanent magnet arrangement, wherein the permanent magnets are arranged one behind the other in the conveying direction, in particular and are evenly spaced apart from each other.

[0026] The stator windings are each supplied with an alternating current, which is supplied from one of the inverters 14 assigned to the respective stator winding.

[0027] Thus, a stator winding is electrically connected and supplied to the respective AC-side connection of the respective inverter.

[0028] The DC-side connections of all inverters 14 are connected in parallel to each other, these parallel-connected connections are also connected in parallel to the DC-side connection of an AC / DC converter 3, in particular a rectifier, and are connected via a series circuit formed from its controllable switch 11 and a controllable interrupter 12 or a fuse to an energy storage device 13, in particular a battery or double-layer capacitor, such as an ultracap.

[0029] The AC-side connection of the AC / DC converter 3 is supplied via a mains filter 2 from a three-phase power supply network 1.

[0030] The mains filter has inductors, such as chokes, and capacitors that are connected between the phase lines of the three-phase power supply network 1 at a star point.

[0031] At the DC-side connection of the AC / DC converter 3, in particular rectifier, a unipolar intermediate circuit voltage is provided, the upper intermediate circuit potential DC+ and the lower intermediate circuit potential DC- of which are also led to a voltage converter 4, which also provides a low voltage, such as 24 volts, which electrically supplies a control unit 5 and a safety control unit 6 as well as the control electronics of the inverters 14.

[0032] The voltage converter 4 is also connected to and supplied by the AC-side connection of the AC / DC converter 3. Specifically, the voltage converter 4 is comprised of two individual voltage converters connected in parallel, ensuring that even if one of the individual voltage converters fails, the low voltage is still available.

[0033] If the three-phase power supply network 1 fails, the voltage converter 4 can still be supplied from the DC link voltage, since the energy storage device 13 maintains the DC link voltage for a period of time.

[0034] The inverters 14 are operated in controlled mode, whereby a higher-level speed controller specifies target speeds to those inverters that supply the stator windings M in operative connection with the permanent magnets of the handset, to which these inverters then regulate themselves. A linear position sensor arranged along the conveyor track detects the linear position of the handset, and from this, the stator windings M currently in operative connection are determined.

[0035] In controlled operation, acceleration or deceleration of the mobile device is possible. The controllable semiconductor switches, which are arranged in half-bridges of the respective inverter 14, are controlled by pulse-width modulation.

[0036] If, during controlled operation, an emergency stop signal is activated during braking, for example for safety reasons, the first individual switches of the controllable switches (9, 10) are closed, thus activating a short circuit and / or discharge via the resistor R. Prior to this, the energy storage device 13 is disconnected and the supply of electrical power from the three-phase power supply network 1 to the DC link is stopped. However, due to line inductances and capacitances, the DC link voltage does not drop instantaneously, but continuously, and in particular steadily. Therefore, according to the invention, even if the DC link is short-circuited or the energy storage device 13 is discharged, controlled operation continues and the controllable semiconductor switches are controlled by pulse-width modulation as long as the respective signal electronics of the inverter are still supplied with sufficient electrical voltage. This results in improved braking performance.

[0037] The single resistor R is connected in series with the two controllable switches 9 and 10, and this series circuit is supplied by the DC link voltage. Therefore, when the controllable switches 9 and 10 are closed, the entire DC link voltage is applied to resistor R. The resistor has a very low resistance, specifically less than 10 ohms, and in particular less than 2 ohms.

[0038] Increased safety is achieved by connecting the two switches 9 and 10 in series. Both switches 9 and 10 must function flawlessly to ensure reliable switching.

[0039] Switches 9 and 10 are controlled by a safety controller 6, which receives a control signal, in particular a release signal or controller lock, from the controller 5 via a signal line 8.

[0040] The intermediate circuit voltage is measured in the AC / DC converter 3, in particular the rectifier, and / or in the voltage converter 4.

[0041] As soon as the intermediate circuit voltage exceeds a threshold value, the energy storage device 13 is charged, for which the controllable switch 11 and the controllable interrupter 12 receive a release signal to close from the AC / DC converter 3, in particular the rectifier, and / or from the voltage converter 4. The second controllable switch 12, on the other hand, receives its release signal from the safety controller 5.

[0042] Preferably, the first controllable switch 11 receives the enable signal from the AC / DC converter 3, in particular rectifier, and / or from the voltage converter 4.

[0043] The controllable interrupter 12 is controlled by the safety controller 6. However, if a fuse is used instead of the controllable interrupter 12, no enable signal or the like is necessary. The two controllable switches 9 and 10 are preferably each designed as double switches, in particular double relays, so that the safety controller 6 can detect, by means of a current loop which is passed through the two controllable switches (9, 10) and can therefore be broken by both the first and the second of the two controllable switches (9, 10), whether at least one of the two switches (9, 10) is open.

[0044] The double switch is designed in such a way that the two individual switches of the respective double switch (9, 10) operate in opposite directions to each other and therefore the breaking of the current loop is synchronously coupled with the connection of the resistor R to the intermediate circuit.

[0045] Therefore, if the safety controller 6 activates the two controllable switches 9 and 10 to connect the resistor R to the intermediate circuit, the current loop will be broken if there is no fault.

[0046] If the safety controller 6 wants to control the two controllable switches 9 and 10 in such a way as to disconnect the resistor R from the intermediate circuit, the current loop will no longer be interrupted by the two controllable switches 9 and 10 if no fault is present. The safety controller 6 has two inputs which are connected to each other via the current loop, i.e., they are short-circuited. Thus, the safety controller 6 can detect a break in the current loop.

[0047] The first controllable switch 9 also has two mechanically coupled, electrically isolated individual switches. The two individual switches of the first controllable switch 9 are therefore always actuated simultaneously. The second controllable switch 10 has two mechanically coupled, electrically isolated individual switches. The two individual switches of the second controllable switch 10 are therefore always actuated simultaneously.

[0048] The current loop passes through both a first of the individual switches of the first controllable switch 9 and a first of the individual switches of the first controllable switch 10.

[0049] The resistor R is connected in series with the second single switch of the first controllable switch 9 and the second single switch of the second controllable switch 10. If one of the two second single switches of the controllable switches (9, 10) fails, the discharge of the intermediate circuit is also stopped.

[0050] Increased safety can be achieved through the redundant design of the controllable switches (9, 10). The control of the switches (9, 10) is also safety-oriented, in that the safety controller 6 only activates the two switches (9, 10) when a corresponding enable signal is transmitted from the controller 5 via the signal line 8.

[0051] When the synchronous linear motor is to brake the handset, the energy storage device 13 is first disconnected from the DC link by opening the controllable switch 11 and the interrupter 12. In addition, the supply of electrical power from the AC power supply network 1 is stopped, in particular by stopping the operation of the AC / DC converter 3, specifically by disconnecting the DC-side connection of the AC / DC converter 3. Then the resistor R is connected to the DC link and discharges it.

[0052] According to the invention, the handset is always in operative connection with all stator windings whose vertical projection in the rail direction overlaps with the vertical projection of the permanent magnets of the handset, so that when braking, the generator-generated current is diverted from not just one but several stator windings into the intermediate circuit and supplied to the resistor R.

[0053] In further embodiments according to the invention, a third series circuit is connected in parallel to the series circuit, which has a second resistor R and in turn two further controllable switches, so that if one of the two resistors R fails, at least the other resistor carries out the discharge of the intermediate circuit - albeit with an increased time constant.

[0054] Reference symbol list

[0055] 1 Three-phase power supply network

[0056] 2 mains filters

[0057] 3 AC / DC converters, in particular rectifiers

[0058] 4 voltage converters

[0059] 5 Control

[0060] 6 Safety control

[0061] 7 Emergency stop signal

[0062] 8 Signal line

[0063] 9 controllable switches, in particular contactors

[0064] 10 controllable switches, in particular contactors

[0065] 11 controllable switches

[0066] 12 controllable interrupter or fuse

[0067] 13 Energy storage

[0068] 14 inverters

[0069] R resistance

[0070] M Stator windings

[0071] DC+ upper intermediate circuit potential

[0072] DC lower intermediate circuit potential

Claims

1. Patent claims:

1. A system with a synchronous linear motor, wherein a mobile unit is movably arranged along a conveyor section and stator windings of the synchronous linear motor are arranged along the conveyor section, wherein the mobile unit has a permanent magnet arrangement whose permanent magnets are in operative connection with the stator windings, wherein the respective stator winding is electrically supplied from the AC-side connection of a respective inverter, wherein the DC-side connections of the inverters are connected in parallel to each other and to a first series circuit, which consists of a resistor R and two first controllable switches, wherein a second series circuit can be connected in parallel to the series circuit, which has at least one energy storage device and one controllable switch.

2. System according to claim 1, characterized in that the second series circuit additionally has a fuse or a further controllable switch.

3. System according to one of the preceding claims, characterized in that the DC-side connection of an AC / DC converter, in particular rectifier, is electrically connected in parallel to the series connection.

4. System according to one of the preceding claims, characterized in that a voltage converter is electrically supplied from the DC-side connection of the AC / DC converter, in particular rectifier, which on the one hand can also be supplied from a three-phase power supply network and on the other hand provides a low voltage, in particular 24 volts.

5. System according to one of the preceding claims, characterized in that a third series circuit is connected in parallel to the series circuit, which has a second resistor R and in turn two second controllable switches.

6. System according to one of the preceding claims, characterized in that each first controllable switch has a first single switch and a second single switch mechanically coupled to the first single switch for synchronous switching, wherein the first resistor R is connected in series with the first single switch of the first controllable switch and with the first single switch of the second controllable switch. - 14 - 7. System according to one of the preceding claims, characterized in that the energy storage device comprises a DC / DC converter and an accumulator and / or double-layer capacitor, in particular an ultracapacitor, wherein the DC / DC converter is connected to the intermediate circuit via the second series connection with its first DC-side connection and is electrically connected to the accumulator and / or double-layer capacitor, in particular an ultracapacitor, with its second DC-side connection, in particular wherein the electrical power flow between the energy storage device and the energy storage device is controllable by means of the DC / DC converter.

8. System according to one of the preceding claims, characterized in that a series circuit formed from the second single switch of the first controllable switch and the second single switch of the second controllable switch makes two inputs of a safety controller electrically connectable to each other.

9. System according to one of the preceding claims, characterized in that the second individual switches are open when the first individual switches are closed, in particular and vice versa.

10. System according to one of the preceding claims, characterized in that the permanent magnet arrangement of the handset is always in operative connection with several stator windings and / or the perpendicular projection of the permanent magnet arrangement of the handset into a horizontal plane comprises the perpendicular projections of several stator windings into this horizontal plane. - 15 - 11. System according to one of the preceding claims, characterized in that a first voltage converter can be supplied from the parallel connection of the DC-side terminals of the inverters, which provides a low voltage, in particular a supply voltage of 24 volts, to a control system and / or the inverters, wherein the first voltage converter can additionally be supplied from a three-phase power supply network, which feeds the AC-side terminal of the AC / DC converter, in particular rectifier.

12. System according to one of the preceding claims, characterized in that a second voltage converter is connected in parallel to the first voltage converter, wherein a first voltage converter can be supplied from the parallel connection of the DC-side terminals of the inverters, which provides a low voltage, in particular a supply voltage of 24 volts, to a control system and / or the inverters, wherein the first voltage converter can additionally be supplied from a three-phase power supply network, which feeds the AC-side terminal of the AC / DC converter, in particular rectifier. - 16 - 13. Method for operating a plant, in particular according to one of the preceding claims, characterized in that in a first method step the inverters are operated in controlled operation, wherein the controllable semiconductor switches of the inverters are controlled by pulse width modulation and an energy storage device is connected in parallel to the parallel connection of the DC-side terminals of the inverters and the DC-side terminal of the AC / DC converter, in particular rectifier, is connected in parallel to the parallel connection of the DC-side terminals of the inverters, in a second method step the resistor R, in particular for discharging, is connected in parallel to the DC-side terminals of the inverters connected in parallel to each other.

14. Method according to one of the preceding claims, characterized in that in the second method step the controlled operation is continued, in particular as long as sufficient voltage is present.

15. Method according to one of the preceding claims, characterized in that, prior to the second method step, the energy storage device is disconnected from the DC-side connections of the inverters and the DC-side connection of the AC / DC converter is also disconnected from the DC-side connections of the inverters.

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