Power supply system and tracked vehicle

Abstract

In a power supply system comprising an electric generator, a DC intermediate circuit, at least one rechargeable electrical energy storage, which is connected to the DC intermediate circuit, a rectifier via which the electrical generator is connectable to the DC intermediate circuit, and at least a first inverter, the DC side of which is supplied with direct current from the DC intermediate circuit and the AC side of which is connectable to an electrical load, and further comprising a control device which regulates the generator in dependence on the load of the electrical load, it is provided that the control device is designed to switch between a first and a second operating mode of the power supply system, wherein in the first operating mode the electrical energy generated by the electrical generator is supplied via the rectifier to the DC intermediate circuit, and in the second operating mode the generator is connected to the load in parallel with the inverter.

Claims

1. A power supply system comprising: an electric generator, a DC intermediate circuit, at least one rechargeable electrical energy storage, which is connected to the DC intermediate circuit, a rectifier via which the electrical generator is connectable to the DC intermediate circuit, and at least a first inverter having a DC side and an AC side, the DC side of which is supplied with direct current from the DC intermediate circuit and the AC side of which is connectable to an electrical load, and the system further comprising: a control device which regulates the electrical generator in dependence on the electrical load, characterized in that the control device is designed to switch between a first operating mode and a second operating mode of the power supply system, wherein, in the first operating mode, electrical energy generated by the electrical generator is entirely supplied via the rectifier to the DC intermediate circuit, and wherein, in the second operating mode, the generator is connected to the electrical load in parallel with the inverter.

2. The power supply system according to claim 1, characterized in that the control device is designed to switch from the first operating mode to the second operating mode, when a limit value of the electrical load is exceeded.

3. The power supply system according to claim 1, characterized in that the rectifier is designed as a bidirectional power converter, with which the control device cooperates such that the bidirectional power converter in the first operating mode is operable as a rectifier and in the second operating mode the bidirectional power converter is operable as a second inverter with a DC side and an AC side, the AC side of the second inverter being connectable to the electrical load in parallel to the first inverter.

4. The power supply system according to claim 1, characterized in that the rectifier and the first inverter are connected in parallel between the DC side and the AC side and that the electrical generator via a first switching device is connectable to an AC side of the rectifier and that between the AC side of the rectifier and the AC side of the first inverter, a second switching means is provided.

5. The power supply system according to claim 1, characterized in that the generator is configured to be driven by an internal combustion engine.

6. The power supply system according to claim 5, characterized in that a thermoelectric generator is connectable with the DC intermediate circuit.

7. The power supply system according to claim 6, characterized in that heat energy of exhaust gas from the internal combustion engine is supplied to the thermoelectric generator.

8. The power supply system according to claim 1, characterized in that a photovoltaic system is connectable with the DC intermediate circuit.

9. The power supply system according to claim 1, characterized in that the control device is designed to monitor the electrical load and, based thereon, the control device is configured to regulate voltage, current and/or frequency of the power supply system.

10. The power supply system according to claim 4, characterized in that the generator, the rectifier and the first inverter are connected via a common matching transformer to a line, via which the electrical load is configured to be supplied with electrical energy and to which, with an interposition of a third switching device, a power supply network is connectable.

11. The power supply system according to claim 10, characterized in that the electrical load is connectable to the line with the interposition of a fourth switching device.

12. The power supply system according to claim 11, characterized in that an AC side of the rectifier between the first switching device and the second switching device is connectable to the line via a line connection that is connected in parallel to a matching transformer, wherein a line connection has a fifth switching device, and wherein the line connection on a load side is separable from the matching transformer by the fourth switching device.

13. A tracked vehicle comprising a crawler chassis, a power supply system according to claim 1, an electric drive for the crawler chassis powered by the power supply system, a transport platform, and a power electronics circuit having at least one three-phase AC terminal for external loads, the transport platform being adapted to receive the power supply system.

14. The power supply system according to claim 1, wherein the electrical load is supplied via the inverter with electrical energy from the DC intermediate circuit.

15. The power supply system according to claim 8, wherein the photovoltaic system is connectable with the DC intermediate circuit by means of a DC-DC converter.

Description

(1) The invention will be explained in more detail with reference to an embodiment schematically illustrated in the drawing.

(2) FIG. 1 shows a perspective view of a tracked vehicle according to the invention,

(3) FIG. 2 shows a side view of the tracked vehicle according to FIG. 1,

(4) FIG. 3 shows a front view of the tracked vehicle according to FIG. 1 and

(5) FIG. 4 shows a schematic representation of a power supply system according to the invention.

(6) FIGS. 1 to 3 show a tracked vehicle 1 with a crawler chassis 2, the crawler chassis 2 comprising two parallel drive chains 3. An unspecified electric motor provides the drive of the drive chains 3. The crawler chassis 2 carries a rigid frame 4, which has a transport platform 5 extending substantially over the entire length of the tracked vehicle 1. The frame 4 is provided at the front and the rear of the vehicle 1 with laterally extendable frame members 6, at the free ends of which support feet 7 are each arranged, which are extendable in the direction of the arrow 8 against the ground.

(7) On the frame 4, a crane structure is further arranged, comprising a boom 9 with three boom arms 10 pivotally mounted relative to each other. Furthermore, the frame 4 carries a lifting device 11 for roll-off containers.

(8) To supply the electric drive of the crawler chassis 2, the vehicle 1 comprises two electrical energy storages 12 (FIG. 2). The electrical energy storage devices 12 feed a power electronics circuit 13 with at least one three-phase alternating current connection for external consumers.

(9) The transport platform 5 is designed such that it can carry a schematically indicated power supply system 14. The power supply system 14 has, for example, a diesel engine and has suitable carrying hooks or the like, in order to be picked up by the loading crane 9 and lifted onto the transport platform 5 or set down from the same. The power supply system 14 has connections, not shown, via which the power supply system 14 can be connected to a charging electronics of the electrical energy storage 12 to charge them.

(10) FIG. 4 shows a schematic representation of a power supply system 14 according to the invention. The power supply system 14 includes a bidirectional power converter 15 and an inverter 16, which are connected to a DC intermediate circuit 17. The DC intermediate circuit 17 is connected to an electrical energy storage 18, a thermoelectric generator 19 and, via a DC-DC converter 20, to a photovoltaic system 21. By a connection, not shown, the DC intermediate circuit can also be connected to an electrical energy storage 12 of the tracked vehicle 1.

(11) On the AC side, the power supply system 14 has a generator 22 which is connected via a first switching unit 23 to the power converter 15 and, in addition via a second switching unit 24, to the inverter 16 and the load 25.

(12) The AC side of the power converter 15 and the inverter 16 is connected via a matching transformer 26 to a line 27, via which the load 25 is supplied with electrical energy with the interposition of a fourth switching device 30. Furthermore, an external power supply grid 28 can be connected to the line 27 with the interposition of a third switching device 29. A line connection 31 functioning as a bypass line, which has a fifth switching device 32, connects the AC side of the power converter 15 between the first switching device 23 and the second switching device 24 to the line 27, the line connection 31 being connected between the switching device 30 and the load 25.

(13) In operation, the power supply system 14 operates as follows. In the first operating mode, when the load required by the load 25 is not higher than average, the first switching unit 23 is closed and the generator 22 is connected to the electrical energy storage 18 via the power converter 15 operated as a rectifier and supplies it with current. The second switching unit 24 is open. As soon as the electrical energy storage 18 is fully charged, the generator 22 switches off. The load 25 is supplied with power by the DC intermediate circuit and possibly by the electrical energy storage 18, the thermoelectric generator 19 and the photovoltaic system 21 via the inverter 16.

(14) If the energy required by the load is greater than the DC intermediate circuit 17 can provide, also the second switching unit 24 is closed and the power supply system switches to the second mode of operation, so that the generator 22 is connected directly, parallel to the DC intermediate circuit 17, with the load 25. Furthermore, in this state, the power converter 15 can be operated as an inverter, so that the DC intermediate circuit 17 feeds the load 25 both via the inverter 16 and via the power converter 15. As a result, the output power provided to the load 25 can be more than doubled.

(15) As soon as the load becomes smaller, the control device opens the second switching unit 24 and the generator 22 again feeds the electrical energy storage 18 (first operating mode).

(16) In addition, energy is generated by the photovoltaic system 21 and the thermoelectric generator 19 and introduced into the DC intermediate circuit.

(17) The switching between the two operating modes is performed by a control device, not shown, which also controls the generator in response to the load of the electrical load.

(18) By the possibility of switching between the first and the second operating mode, it is possible to simultaneously cover an optimum efficiency of the generator 22 in normal operation (first operating mode) and a high output power in the second operating mode.

(19) In order to synchronize the generator 22, when starting, with the frequency of the external power supply grid 28 or with the frequency of the inverter 16, the power converter 15 can be used as an electric brake. For this purpose, the second switching device 24 is initially opened, while the first switching device 23 is closed, and the generator 22 is connected to the load 25 after synchronization by closing the second switching device 24.

(20) Furthermore, the inverter 16 may be formed as a bidirectional power converter. This makes it possible to supply the DC intermediate circuit 17 from the external power supply grid 28 with direct current and thereby to charge the energy storage 18. This allows operation of the power supply system 14 as an uninterruptible power supply (UPS) to ensure the supply of the load 25 from the DC intermediate circuit and/or from the generator 22 in case of failure in the external power grid 28. For this purpose, the load is first supplied by the power supply network 28 with the switching devices 29 and 30 being closed, wherein, if desired, the DC intermediate circuit 17 together with the energy storage device 18 can be charged via the rectifier 15 at the same time. The switching devices 23 and 24 are open in this case. If the external power supply falls below a critical point and no longer provides sufficient energy, the switching device 29 is opened and the power supply system 14 is set to the isolated operation mode by having the DC intermediate circuit 17 supply the load 25 via the inverter 16.

(21) In the mentioned operation as an uninterruptible power supply one can also proceed so that excess energy from the DC intermediate circuit 17 is fed back into the power grid 28, e.g. if a connected photovoltaic system 21 supplies sufficient energy.

(22) Furthermore, a pure generator operation is possible with the power supply system 14 when the DC intermediate circuit 17 fails or the energy storage 18 is empty. In this case, the generator 22 is started with the switching devices 23, 24 and 30 being open and set to the target frequency and target voltage. Thereafter, the switching devices 23, 24 and 30 and possibly the switching devices associated to the matching transformer 26 are closed, so that the load 25 is supplied with energy. By putting the power converter 15 into operation, the AC power supplied by the generator can be kept stable, wherein the power converter 15 can be put into operation either before or after the closing of the switching device 30.

(23) Optionally, a bypass function can be realized by having the generator 22 supply the load 25 as described above, if necessary while maintaining the power converter 15 stable, however not via the matching transformer 26, but rather via the line connection 31. In this case, the switching device 30 is open and the switching devices 29 and the switching devices associated to the matching transformer 26 are closed, so that the energy storage 18 is charged via the power converter 18 (operated as a rectifier) from the power grid 28.