Electrical drive system and energy storage apparatus therefor

Patent metadata

Field	Value
Publication number	US-10224856-B2
Application number	US-201715668175-A
Country	US
Kind code	B2
Filing date	Aug 3, 2017
Priority date	Jun 11, 2013
Publication date	Mar 5, 2019
Grant date	Mar 5, 2019

Abstract

A drive system may have at least one electric motor which can be fed via power electronics which can be connected via a DC circuit to a voltage source and an energy storage apparatus for buffering energy fed back from the electric motor. An energy storage apparatus for such a drive system may include at least one electrical storage block, a bidirectional DC/DC converter for connecting the named DC voltage circuit to the internal voltage circuit of the storage block and a control unit for controlling the DC/DC converter. The control unit may include output and feed control means for controlling the DC/DC converter. The DC/DC converter, the storage block and the control unit may be combined into an energy storage unit having a common housing in which the named components are received and at whose outer side two connections are provided for connecting to the DC voltage circuit.

First claim

The invention claimed is:

1. A travel drive system, comprising at least one electric motor fed via power electronics, the power electronics comprising a DC voltage circuit connecting the at least one electric motor to a voltage source, and at least one energy storage apparatus for buffering energy fed back from the electric motor, wherein said energy storage apparatus includes at least one electrical storage block, a DC/DC converter for the connection of the DC voltage circuit to an internal voltage circuit of said storage block, and a control apparatus for controlling the DC/DC converter, wherein the control apparatus is configured to control the DC/DC converter both for outputting of current from the storage block to the DC voltage circuit and for feeding of current from the DC voltage circuit into the storage block, wherein the DC/DC converter is bidirectional, and wherein the storage block, the DC/DC converter, and the control apparatus together form a plug-and-play module with outer side power connections for connection of the plug-and-play module to the DC voltage circuit of the power electronics.

2. The travel drive system of claim 1 , wherein the storage block, the DC/DC converter, and the control apparatus are accommodated in a common housing, and wherein two power connections are provided on an outer side of the common housing for connection to the DC voltage circuit of the power electronics.

3. The travel drive system of claim 1 , wherein a maximum voltage of the storage block is kept lower than a minimum voltage of the DC voltage circuit.

4. The travel drive system of claim 1 , wherein feeding of fed back energy of the electric motor into the energy storage apparatus and outputting of buffered energy from the energy storage apparatus to the DC voltage circuit both take place via the DC/DC converter of the energy storage apparatus.

5. A method for operating a travel drive system, comprising:
travelling a lifting gear of a lifting apparatus, wherein electrical energy is buffered in a work cycle of the lifting gear,
lowering or braking said lifting gear, and upon lowering or braking of said lifting gear, storing electrical energy in at least one electrical storage block of at least one energy storage apparatus, the energy storage apparatus further comprising a DC/DC converter;
raising the lifting gear with at least one electric motor, the electric motor fed via power electronics, the power electronics comprising a DC voltage circuit connecting the electric motor to a voltage source, wherein the DC voltage circuit is further connected to an internal voltage circuit of the storage block via the DC/DC converter; and
upon raising of the lifting gear, releasing the stored electrical energy from the storage block of the energy storage apparatus.

6. The method of claim 5 , wherein, when the electric motor brakes, electrical energy is fed from the electric motor into the DC voltage circuit and stored in a plurality of dual-layer capacitors of the storage block, and wherein, when the electric motor raises the lifting gear, the electrical energy is fed back from the plurality of dual-layer capacitors of the storage block to the electric motor.

7. A lifting apparatus comprising a travel drive system for travelling a lifting gear, said travel drive system having at least one electric motor fed via power electronics, the electric motor connected via a DC voltage circuit of the power electronics to a voltage source, and at least one energy storage apparatus for buffering energy fed back from the electric motor, wherein the energy storage apparatus includes at least one electrical storage block, a DC/DC converter for connection of the DC voltage circuit to an internal voltage circuit of said storage block, and a control apparatus for controlling the DC/DC converter, wherein the control apparatus is configured to control the DC/DC converter both for outputting of current from the storage block to the DC voltage circuit and for feeding of current from the DC voltage circuit into the storage block, wherein the DC/DC converter is bidirectional, and wherein the storage block, the DC/DC converter, and the control apparatus are combined to form an energy storage unit having power connections at an outer side thereof for connection of the energy storage unit to the DC voltage circuit of the power electronics.

8. The lifting apparatus of claim 7 , wherein said voltage source is a grid feeding said power electronics via said DC voltage circuit.

9. The lifting apparatus of claim 7 , wherein said voltage source is a generator driven by a combustion engine and feeding said power electronics via said DC voltage circuit.

10. The lifting apparatus of claim 7 , wherein the storage block, the DC/DC converter, and the control apparatus together form a plug-and-play module having a common housing in which the storage block, the DC/DC converter, and the control apparatus are received, the common housing having power connections at an outer side thereof, the power connections configured to be releasably connected to the DC voltage circuit of the power electronics.

11. The lifting apparatus of claim 7 , wherein the storage block comprises at least one dual-layer capacitor for energy storage.

12. The lifting apparatus of claim 10 , wherein the storage block and/or the DC/DC converter and/or the control apparatus are linked in the common housing to an internal cooling circuit which has coolant connections at the common housing for connection to an external cooling circuit.

13. The lifting apparatus of claim 12 , wherein the control apparatus is configured to control the internal cooling circuit and/or the external cooling circuit in dependence on a temperature of an electric component in the common housing and/or on an environmental temperature and/or on a temperature inside the common housing.

14. The lifting apparatus of claim 12 , wherein the coolant connections are configured as pluggable connections.

15. The lifting apparatus of claim 10 , wherein the common housing is configured as divisible and comprises a plurality of housing parts configured to be put together to form the common housing, and wherein different electric components of the energy storage unit, which are configured to be connected to one another by plug-in contacts, are accommodated in different housing parts of the plurality of housing parts.

16. The lifting apparatus of claim 15 , wherein the plug-in contacts, which are configured to automatically come into contact on the putting together of the housing parts, are provided at interfaces of the housing parts.

17. The lifting apparatus of claim 10 , wherein a warning signal device is provided for outputting a warning signal when the storage block is still charged with energy, and/or wherein a disconnect switch is provided for disconnecting the storage block and/or for deenergizing the power connections at the common housing.

18. The lifting apparatus of claim 7 , wherein a discharge circuit is provided for converting energy stored in the storage block into heat, the discharge circuit configured to be controlled by a control command from outside.

19. The lifting apparatus of claim 7 , wherein the control apparatus is configured to determine an energy index and to provide and/or transfer this energy index to a higher-ranking control, with the energy index representing energy available in the storage block.

20. The lifting apparatus of claim 7 , wherein the control apparatus is configured to, in response to a control signal from outside, convert def

Assignees

• Liebherr Components Biberach Gmbh
• Liebherr Components Biberch Gmbh

Inventors

• Schuster Wolfgang
• Fenker Oliver
• Welser Sven

Classifications

• H01M8/04858

  Electric variables · CPC title

• B60L11/1881

  Operations & Transport · mapped topic

• H02P27/06

  using DC to AC converters or inverters (H02P27/05 takes precedence) · CPC title

• H02P27/04 Primary

  using variable-frequency supply voltage, e.g. inverter or converter supply voltage · CPC title

• B60K6/28

  characterised by the electric energy storing means, e.g. batteries or capacitors · CPC title