EP2697095A2

EP2697095A2 - Energy supply

Info

Publication number: EP2697095A2
Application number: EP12726762.3A
Authority: EP
Inventors: Rolf Fischperer; Michael Meinert; Peter Eckert
Original assignee: Siemens AG
Current assignee: Siemens AG
Priority date: 2011-05-31
Filing date: 2012-05-23
Publication date: 2014-02-19
Also published as: DE102011076787A1; WO2012163741A2; WO2012163741A3

Abstract

The invention relates to a stationary energy store for temporarily storing electric energy in a stationary energy supply network for a vehicle that can be electrically driven, comprising a stationary storage unit, a first buck converter for charging the stationary storage unit, a first boost converter for discharging the stationary storage unit, a second boost converter for charging the stationary storage unit, and a second buck converter for discharging the stationary storage unit. An energy system comprises the stationary energy store and the vehicle that can be electrically driven, wherein the vehicle comprises a mobile energy store for storing electric drive energy, and the mobile energy store comprises a mobile storage unit configured to be charged from the stationary storage unit. The invention further relates to a method therefor and a corresponding computer program product.

Description

description

The invention relates to a stationary energy store having the features of claim 1 and to an energy system having the features of claim 6.

State of the art

An electrically drivable vehicle, in particular a Li ^¬ nienfahrzeug such as a train, a tram or a bus is permanently or temporarily connected to a power grid. The vehicle has a mobile energy storage, which is rechargeable from the power grid, and caches the electrical energy that can be used later for driving the vehicle. In this case, the mobile energy storage can be charged in the so-called recuperator while the vehicle is decelerating.

EP 0968873 Al suggests to exchange electrical energy between ei ^¬ nem first braking the vehicle and a second, accelerating the vehicle, both of which are electrically connected to a power grid.

EP 1 864 849 A1 describes a system in which a stationary energy store outside the vehicle and a mobile energy store are provided on board the vehicle, wherein the mobile energy store is set up to be charged from the stationary energy store.

In "A Supercapacitor-Based Energy Storage Substation for volume days Compensation in Weak Transportation Networks", IEEE Transactions on Power Delivery, vol 19, no. 2, April 2009, Alfred Rufer, David hotelier and Philippe Barra ^¬ de describe a technique for Caching of electrical energy in a network-based traffic system. The known stationary or mobile energy storage for storing normally include an accumulator or a capacitor, in particular a double-layer Kondensa ^¬ gate, and the stored energy in the energy storage is dependent on a voltage of the energy store.

Particularly in an embodiment in which the vehicle is connected to the energy supply network only during short phases, for example at predetermined stops, rapid energy transfer from the stationary energy store to the mobile energy store is required. The power supply network can be fed from another electrical supply network. The voltage of a fully charged stationary energy storage would normally exceed the voltage prevailing in the power supply voltage, which is why the stationary electrical energy storage is charged only to a voltage that does not exceed the voltage of the electrical supply network. The invention is therefore based on the object a host ^¬ nomic utilization of a major portion of the electrical storage capacity of the stationary energy storage for enabling ^¬ union without the need for a high-performance power supply is needed.

The invention solves this problem by means of a stationary energy storage with the features of claim 1 and an energy system with the features of claim 6. Unteransprü ^¬ che give preferred embodiments again.

Disclosure of the invention

A stationary energy store for the temporary storage of electrical energy in a stationary power supply network for an electrically drivable vehicle comprises a stationary storage device, a first buck converter for charging the stationary storage device, a first boost converter for discharging the stationary storage device. Position, a second boost converter for charging the stationary storage device and a second buck converter for discharging the stationary storage device. According to the invention, the stationary storage device can be charged from the supply network to a voltage which is above the voltage of the supply network and which can furthermore be discharged into the constant-voltage power supply network, while the voltage of the stationary storage device is below the voltage of the energy supply network , An electric storage capable ^¬ ness of the stationary storage device can thus be used to optimize and an energy exchange can be accelerated. Auxiliary and protective elements of the stationary energy storage can be used in all operating conditions, so that the stationary energy storage can require little additional manufacturing and operating costs. The additional ^step- up or step-down converters can correspond to known setters, so that a new development of the setting divider can be dispensable.

The stationary storage device of the stationary energy store can be charged and discharged in a short time between voltage limits, which are independent of the voltage of the power supply network. So it suffice even a rela ^¬ tively low voltage and a relatively low power of the supply network to charge the stationary energy storage. Thereby, a connection of the stationary energy storage to the supply network can be done easily and inexpensively. In this case, the first and the second step-up converter as well as the first and second step-down converter each comprise an actuating element and a control throttle, wherein the Stelldros ^¬ least at least two of the setting divider are identical to each other. It can also be the control chokes of three or all four setting divider identical to each other. As a result, a component cost can be reduced, which cost advantages, ge ^¬ increased reliability and a reduced space can be achieved. The stationary energy store may be configured to discharge the energy stored in the stationary storage device into the vehicle. As a result, a supply of the vehicle with electrical energy, in particular during a time-limited charging process, be optimized.

The stationary energy store may further comprise a control device, which is set up to charge or discharge the stationary storage device in different operating states. In a first operating state, the stationary memory device is charged by means of the first buck converter from the power supply network to a voltage which is below a voltage of the power supply network. In a second operating state, the stationary storage device is charged by means of the second boost converter from the power grid to a voltage higher than the voltage of the Energieversorgungsnet ^¬ zes. In a third operating state, the stationary memory device is discharged by means of the second buck converter to provide a voltage in the power supply network that is below the voltage of the stationary memory device, and in a fourth operating state, the stationary memory device is discharged by the first boost converter to a voltage provide in the power grid, which is above the voltage of the stationary storage device.

The time required for charging or discharging each energy storage can be different in the various operating conditions and be determined by the given data of the components involved, in particular rated current and rated voltage. In particular, the energy supply network can have a low efficiency, which leads to comparatively long charging times for the stationary energy store, wherein the discharging of the stationary storage into the mobile energy storage, nevertheless, only a comparatively short It may take time if the energy stores are rated for high performance.

By means of the control device, the described elements of the stationary ele- energy storage device in accordance with the un ^¬ terschiedlichen operating states are controlled. Thereby may be achieved an improved, more flexible and more particularly to auto ^¬ mated treatment of the different operating states. By converting the voltages using the boost and buck converters, excessive current flow can be prevented.

In one embodiment, the power supply network carries a substantially constant voltage. The voltage of the energy supply network may be subject to smaller fluctuations and certain disturbances may be superimposed, as a result of which the energy supply network is not yet operated with different voltages or with a specifically varying voltage. A design of the power supply network and a dimensioning of components, in particular in the stationary energy storage and on board the vehicle can be facilitated by the substantially constant voltage.

In one embodiment, the power supply network leads a DC voltage fed from a rectifier. The rectifier can be fed from the electrical supply network. To deny a base load of the power supply network, the DC voltage fed from the rectifier can be sufficient. The stationary energy storage can help to cover a peak load, which can arise at ^¬ example, the rapid transfer of electrical energy in the vehicle or in several vehicles simultaneously. According to another aspect, a power system includes the stationary energy storage device and the electric automobile described, the vehicle having a mobile Ener ^¬ giespeicher for storing electrical drive energy environmentally summarizes and the mobile energy storage comprises a mobile storage device which is adapted to be charged from the statio ^¬ nary storage device. The energy system according to the invention can provide improved from utilization ^¬ a storage capacity of one or both energy ^¬ memory. A charging time of the mobile energy storage device can be reduced according to the energy system according to the invention.

In one embodiment, the second buck converter is adapted to charge the mobile storage device from the statio nary ^¬ storage device, wherein the second downconverter is arranged on board the vehicle. In this embodiment, a change in the voltage of the power supply network can be made possible, while the voltage of the stationary energy storage exceeds the usual nominal voltage of the power supply network. By providing the low ^¬ converter functionality for discharging the stationary energy storage device or charging the mobile energy accumulator from ^¬ finally on board the vehicle a redundant imple mentation ^¬ of the buck converter can be avoided, whereby cost savings may result. The mobile energy storage device may have a third boost converter for charging the mobile storage device. As a result, a constant voltage can be removed from the mobile energy store, even if the vehicle or the mobile energy store is not connected to the energy supply network.

The energy system may include an electrical connection device for establishing an at least temporary electrical connection between the vehicle and the power supply network. The connection device may comprise, for example, a high-voltage line with sliding contact and / or a track contact. The connection device can do this be configured to produce the electrical connection, for example, only at a stop of the vehicle.

According to a further aspect, the invention comprises a method for charging a mobile electrical energy store with a mobile storage device comprising a stationary electrical energy store with a stationary storage device, the method comprising steps of charging the stationary storage device by means of a first step-down converter from a power supply network Voltage of the stationary memory device is under the voltage of the power supply network, the charging of the stationary memory device by means of a first boost converter from the power grid, the voltage of the stationary memory device is above the voltage of the power supply network, discharging the statio ^¬ nary memory device by means of a second buck converter in order to provide a voltage in the power supply network which is below the voltage of the stationary storage device and the discharge of the s tationary storage means by means of a second boost converter to provide a voltage in the power supply network, which is above the voltage of the stationary storage device comprises.

The method can be advantageously carried out above ^¬ be written stationary energy storage or the NEN-described ^¬ power system by means of. According to yet another aspect of the invention, a computer program product comprises program code means for performing the described method when the method is executed on a processing device or stored on a computer-readable data memory.

Brief description of the figures The invention will now be described in more detail with reference to the attached figures, in which:

1 shows a circuit diagram of an energy system;

2 shows voltage diagrams on the energy system from FIG. 1;

3 shows a circuit diagram of a variation of the energy system

FIG. 1;

4 shows a circuit diagram of a further variation of the energy system from FIG. 1;

5 shows a circuit diagram of yet another variation of the energy system of FIG. 1; and

6 shows a flowchart of a method for controlling the

Energy system of FIG 1 represents.

Description of embodiments

1 shows a circuit diagram of a power system 100. The power system 100 includes a stationary energy storage (SES) 105 and a vehicle 110 with a mobile power ^¬ memory (MES) 115. The stationary energy storage 105 and the vehicle 110 are by means of a power supply system 120 connected to each other , The power grid 120 may include a high voltage power line, such as a catenary or bus bar, that is contacted with a sliding contact 125 attached to the vehicle 110. It may also be provided a track contact, which is contacted by an electrically conductive wheel 130 or a corresponding sliding contact of the vehicle 110.

The power supply network 120 is usually a DC power supply network whose nominal voltage can be, for example, 400 V. The power grid 120 is primarily powered by a rectifier 135, which is operated, for example, with three-phase alternating current from an AC power supply network. A main switch 140 connects the stationary energy storage 105 to the power supply network 120. From the main switch 140, a positive voltage passes through a precharging device 145 to a mains choke 150. The precharging device 145 and the mains choke 150 have the task of electrical interference between the power supply network 120 and the remaining components of the stationary energy storage 105 to decouple. A backup capacitor 155 extends from the mains choke 150 to an electrically negative terminal of the main switch 140 and serves to smooth the high voltage applied to it ^¬ .

An adjusting throttle 160 is ver ^¬ connected with four actuators 165, that two step-up converter ( "step-up converter") and two step-down converter ( "step-down converter") are formed. Each of the actuators 165 is symbolically represented by an NPN transistor which includes a freewheeling diode from its emitter to its collector. However, any other switching means for the actuator 165 may be used, such as a FET transistor. The Hochsetzstel ^¬ ler and buck converter have the task of controlling a charging or discharging a stationary memory device 170. The stationary storage device 170 may comprise an accumulator or a capacitor, in particular a double-layer capacitor.

The first buck converter 175 for charging the stationary storage device 170 from the power supply network 120 is formed by the positioning choke 160 and the upper left positioning element 165.

The first step-up converter 180 for discharging the stationary storage device 170 into the power supply network 120 is formed by the positioning choke 160 and the lower-left positioning element 165.

The second boost converter 185 for charging the stationary storage device 170 from the power supply network 120 is formed by the control throttle 160 and the lower right Stell ^¬ element 165.

The second step-down converter 190 for discharging the stationary memory device 170 into the power supply network 120 is formed by the positioning choke 160 and the upper-right positioning element 165.

A current through the control throttle 160 is protected by means of an optional fuse 195. An optional backup ^¬ device 200 is connected in parallel to the stationary storage device 170 and limits the stationary SpeI ^¬ chereinrichtung 170 secures electrically against overvoltage. In the embodiment illustrated in FIG. 1, all setting dividers 175 to 190 are constructed with the same adjusting throttle 160. In other embodiments, a plurality of actuating throttles 160 may be provided, which are assigned in each case in each case one or more of the setting divider 175 to 190.

All control elements 165 can be controlled by means of a control device 210. The controller 210 may be configured to prevent a competing operation of boost converters 175 to 190, as the same parking restrictor 160 umfas ^¬ sen. Usually, the control device 210 controls the sta ^¬ tionary energy storage 105 in one of four different operating conditions, which are briefly explained below.

In the first operating state, the stationary spoke pure ^¬ device is charged from the power supply network 120 170, wherein the voltage of the stationary storage device 170 is less than or equal to the voltage of the power supply network 120th Charging is done in this case by means of the f ^¬ th step-down converter 175th In the second operating state, the stationary spoke pure ^¬ direction is loaded from the power supply network 120 170, wherein the voltage of the stationary storage device 170 is greater than or equal to the voltage of the power supply network 120th The charging takes place in this case by means of the second boost converter 185. During charging, preferably the first buck converter 175 is permanently turned on.

In the third operating state, the stationary storage device 170 is discharged into the energy supply network 120, wherein the voltage of the stationary storage device 170 is greater than or equal to the voltage of the energy supply network 120. The unloading takes place in this case by means of the second buck converter 190.

In the fourth operating state, the stationary spoke pure ^¬ direction is discharged into the power supply network 120 170, wherein the voltage of the stationary storage device 170 is less than or equal to the voltage of the power supply network 120th The unloading is carried out in this case by means of the f ^¬ th boost converter 180. During discharge of the second buck converter 190 is preferential ^¬ as permanent durchgesteu ^¬ ert. By means of said operating conditions, the stationary

Memory means 170 may be alternatively charged from the power grid 120 or discharged into the power grid 120, wherein the voltage of the stationary memory means 170 may each be in a range which is both greater and smaller than the voltage of the grid 120 includes. Apart from disturbances, parasitic effects and load-related variations, the voltage of the power supply network 120 may be kept substantially constant.

The energy supply network 120 may be connected to the stationary energy storage 105 by means of one of seven different connections 220 to 245. It usually comes use only one of the connections, which will be explained below.

The first connection 215 extends to the rectifier 135. This makes it possible for the vehicle 110 even with electrical

Power supply when the stationary energy storage 105 is not available. If the main switch 140 is closed, the mains choke 150 of the stationary energy store 105 can have a smoothing effect on the voltage in the energy supply network 120.

The second link 220 extends to a point between the main switch 140 and the precharging device 145. Thereby, it is possible to charge the stationary Speichereinrich- tung 170 by opening the Hauptaschalters 140 to interrup ^¬ chen.

The third link 225 extends to a point between the precharging device 145 and the choke 150. In this variant, the charging function of the stationary Energiespei ^¬ Chers 105 from the power supply system 120 by opening the switch of the precharging device shown can be interrupted 145th The fourth link 230 extends to a point between the choke 150 and the two left actuators 165. If the vehicle 110 power taken from the electric power supply network ^¬ 120 so doing, the choke 150 is bypassed.

The fifth connection 235 extends to a point between the two left adjusting elements 165 and the associated end of the adjusting throttle 160. As a result, the first buck converter 175 can be bypassed when the vehicle 110 takes energy from the power supply network 120.

The sixth connection 240 extends to the other end of the control throttle 160, with the two right-hand control elements 165 is connected. This variant is only useful if the nominal voltage of the vehicle 110 or 265 is not greater than the voltage of the stationary memory in the defi ^¬ ned state as empty, since the voltage in the vehicle 110 in this case only as large as that of the stationary storage device 170 may be because the boost converter 180 is not effective.

The seventh connection 245 extends to a point between the two right-hand control elements 165 and the stationary one

Memory device 170. In this variant, the restrictions specified with regard to the sixth connection 240 apply, however, the energy removal from the stationary energy store 105 is also possible if none of the setting divider 175 to 190 is available on the part of the stationary energy store 105.

In general, it may be useful to determine the energy flow in its direction from the stationary energy store 105 to the mobile energy store 115 by means of a freewheeling diode (not shown in FIG. 1).

It is understood that, depending on the selected binding Ver ^¬ 215-245 components that fill no more function ER may be omitted, for example, the boost converter 180 in link 240 or 245th

The mobile energy storage 115 of the vehicle 110 is verbun ^¬ by means of a vehicle main switch 250 and a vehicle mains choke 255 with the positive sliding contact 125. An intermediate circuit capacitor 260 is parallel to the mobile energy accumulator 115. The main switch 250, the choke 255 and capacitor 260 are not the owing here ^¬ detected charging concept, but are for the vehicle for providing a defined voltage for the traction motors and auxiliary operating devices, even when operating on a conventional catenary or track. In a similar manner as the stationary energy storage 105 includes of mobile energy storage, a mobile storage device having a parallel connected backup device 270 against overvoltage, wherein the mobile storage device via a third step-down converter 275 or a third boost converter 280 can be charged from the Energieversor ^¬ supply network 120,115,265,265. For this purpose, a control throttle 285 is provided, which forms the setting dividers 275 and 280 in conjunction with Stellelemen ^¬ th 290. Here too, the setting dividers 275 and 280 can alternatively be constructed with dedicated adjusting throttles.

The connection of the control inductor 285 with the control elements 290 is effected by a fuse 295. Functionally, the structure of the illustrated mobile energy storage 115 substantially corresponds to the structure of the stationary described above

Energy storage 105. A control device for controlling the adjusting elements 290 is not shown for clarity. The mobile energy store 115 can be charged in a first operating state by means of the third step-down converter 275, the voltage of the mobile energy store 265 being less than or equal to the voltage of the energy supply network 120 or the energy store 170, without the network stations 175 to 190 of the stationary store Energy storage 105 may be needed. In a second operating state, the mobile energy storage 265 may be discharged by the third boost converter 280 to apply power to the traction motors and

Auxiliary services or the stationary energy storage.

The stored in the mobile energy accumulator 265, electrical energy is preferably for driving the vehicle 110 turns ^¬ ver. In a further embodiment, the mobile energy storage 265 may also be provided during braking of the vehicle

Vehicle 110 to charge. In still another embodiment, the stationary energy storage 105 may also be charged during braking of the vehicle 110. 2 shows voltage diagrams on the energy system 100 from FIG. 1. A left-hand diagram shows a time profile of the voltage U_SES of the stationary memory device 170. A right-hand diagram shows a time profile of the voltage U_SES at the stationary memory device 170 and a time profile of the voltage U_MES corresponding thereto the mobile memory device 265. To the right, respectively times and upwards voltages are applied.

The left graph of Figure 2 shows high a charging curve ^¬ the stationary energy storage device 170. In a first temporal portion Tl in which the voltage U_SES the stati ^¬ onären memory device 170 is smaller than the voltage U_n the power supply system 120 is, the charging of the stationary storage means 170 in the above with reference to FIG 1 described first operating state via the first buck converter 175 the voltage U_SES the stationary storage device 170 exceeds the voltage u_n the power supply system 120, so in a period T2, the stationary SpeI ^¬ chereinrichtung 170 in the second operating state by means of the second boost converter 185 further charged.

The right-hand diagram of FIG. 2 shows a discharge curve of the stationary storage device 170 and a corresponding charging curve of the mobile storage device 265. The curves are based on a charging process of the mobile storage device 265 from the stationary storage device 170. For this, the stationary storage device shall be charged to 170 ^¬ next, for example, under the operating conditions described with Be ^¬ train on the left diagram. In a third time period T3, in which the voltage U_SES of the stationary memory device 170 is greater than a voltage U_MES of the mobile memory device 265, the unloading of the stationary memory device 170 takes place in the mobile memory device 265 in buck converter mode, for example in the third operating state by means of the second buck converter 190. If the voltage U_SES of the stationary memory device 170 falls below the voltage U_MES of the mobile memory device 265, so during a fourth period T4, the mobile ^¬ memory device 265 from the stationary memory device 170 further charged in boost converter operation, for example in the fourth operating state by means of the first boost converter 180th

The temporal course of voltages is shown for illustrative reasons in each case linear, but in fact can be set non-linear gradients, since the power supply ^¬ content with the square of the voltage or decreases.

FIG. 3 shows a circuit diagram of a variation of the energy system 100 from FIG. 1. Essentially, the illustrated energy system 100 differs from the energy system 100 from FIG. 1 in that the upper right control element 165 is missing and thus the second step-down converter 190 is not present. The connections 215 to 245 are not shown and can thus be supplemented as described above with reference to FIG.

The functionality of the second buck converter 190 in drit ^¬ th operation state in which the stationary energy storage is unloaded 170 in the power supply system 120 or via the power supply system 120 to the mobile storage device 265, takes place in the illustrated variation means of the third step-down converter 275 on board the vehicle 110th

FIG. 4 shows a circuit diagram of a further variation of the energy system 100 from FIG. 1.

Is described in a similar manner as described above with reference to Figure 3, the energy system 100 is changed to the effect ^¬ changed from FIG 1 that the third step-down converter 275 on board the vehicle zeugs 110 is omitted. The function of the third step-down converter 275, for example, during the third Betriebszu ^¬ stands is taken over here by the second downconverter 190 in the stationary energy storage 105th To control the control of the third operating state the part of the stationary energy ^¬ memory 105, operating parameters from the vehicle 110, in particular with respect to the mobile energy accumulator 265 may be transmitted to the stationary energy storage 105 that are there placed the control is based. In addition, in the embodiment of FIG. 4, compared to that of FIG. 1, instead of the connection 215, the connection 235 has been selected.

5 shows a circuit diagram of yet another variation of the energy system 100 from FIG. 1. In the illustrated variation, both the first buck converter 175 and the second buck converter 190 are dispensed with. A blocking diode 505 is arranged in the forward direction between the stationary energy storage 105 and the mobile energy storage 115. The

Blocking diode 505 may be disposed at any point of the energy flow, for instance in stationary Ener ^¬ giespeicher 105, the mobile energy accumulator 115, on board the vehicle 110 or in the area of power supply network 120. The embodiment of the energy system 100 illustrated in FIG 5 may be, for Charging the mobile energy storage 115 can be used from the stationary energy storage 105, as long as the voltage of the power supply network 120 U_N is smaller than a minimum voltage U_SES the stationary storage device 170.

6 shows a flowchart of a method 600 for STEU ^¬ s of the energy system 100 of FIG 1. The method 600 can also be used for controlling the power system 100, one of the variants of Figures 3 to fifth For this purpose, if necessary, adjustments are required, which are described above with reference to the corresponding variants. In a first step 605, the stationary memory device 170 is charged from the power supply network 120 by means of the first buck converter 175, the voltage U_SES of the stationary memory device 170 being below the voltage U_N of the power supply network 120. This

Step corresponds to the first operating state described above with reference to FIG.

In a following step 610, the stationary storage device 170 is charged from the energy supply network 120 by means of the second boost converter 185, the voltage U_SES of the stationary storage device 170 being above the voltage U_N of the energy supply network 120. The ^¬ ser step corresponds to the second operating state.

In a further step 615 the stationary SpeI ^¬ chereinrichtung 170 is discharged by the second down converter 190 to provide a voltage U_n in the power supply system 120, which is below the voltage U_SES the stationary storage device 170th This step corresponds to the third operating state.

Finally, in a step 620 the stationary SpeI ^¬ chereinrichtung 170 is discharged by the first up converter 180 to provide a voltage U_n in the power supply system 120, which is above the voltage U_SES the stationary storage device 170th This step corresponds to the fourth operating state. Transitions between steps 605-620 are typically in the order described, returning to step 605 after step 620. In principle, however, other transitions are possible if necessary, as indicated in Figure 6 by the arrows.

Claims

claims

A stationary energy store (105) for temporary storage of electrical energy in a stationary energy supply network (120) for an electrically driven vehicle (110), wherein the energy store (105) comprises the following elements:

a stationary storage device (170);

- A first buck converter (175) for charging the stationary memory device (170);

a first boost converter (180) for discharging the stationary storage device (170),

a second boost converter (185) for charging the stationary storage device (170),

a second buck converter (190) for discharging the stationary memory device (170),

- wherein the first and second step-up converter (180, 185) or step-down converter (175, 190) each comprise an actuating element (165) and a control inductor (160) and the actuating throttles (160) of at least two of the setting dividers (175-190) are identical to each other.

2. Stationary energy storage (105) of claim 1, WO-in stationary energy storage (105) to be directed ^¬ is to unload in the stationary storage device (170) energy stored in the vehicle (110). 3. stationary energy storage (105) according to any one of the preceding claims, further comprising a control device (210) which is adapted to the sta ^¬ tionary storage device (105) alternatively

- By means of the first buck converter (175) from the power grid (120) to a voltage

To charge (U_SES), which is below a voltage (U_N) of the power grid (120); - To charge by means of the second boost converter (185) from the power supply network (120) to a voltage (U_SES), which is above the voltage (U_N) of the power supply network (120);

- to de ^¬ load by means of the second buck converter (190) to provide a voltage (U_N) in the power supply network (120), which is below the voltage (U_SES) of the stationary memory device (170); or

- by means of the first boost converter (180) to Entla ^¬ to provide a voltage (U_n) in the power supply ^¬ network (120), which is above the voltage (U_SES) of stationary storage means (170).

Stationary energy storage device (105) according to any one of the preceding claims, wherein the power supply ^¬ network (120) a constant voltage (U_n) leads.

Stationary energy store (105) according to any one of the preceding claims, wherein the power supply ^¬ network (120) from a rectifier (135) is fed ^¬ fed DC voltage. 6. Energy system (100), comprising a stationary energy store (105) and an electrically driven vehicle (110) according to one of the preceding claims, wherein the vehicle (110) comprises a mobile energy storage device (115) for storing electrical drive energy and the mobile Energy storage (115) a mobile

Storage means (265) adapted to be charged from the stationary storage means (170).

The power system (100) of claim 6, wherein the second buck converter (190) is configured to charge the mobile memory device (265) from the stationary storage device (170) and the second buck converter (190). Setting divider (190) on board the vehicle (110) angeord ^¬ net is.

8. Energy system (100) according to claim 6 or 7, wherein the mobile energy store (265) comprises a third step-up converter (280) for charging the mobile storage device (265).

9. energy system (100) according to any one of claims 6 to 8, further comprising an electrical connection means (125) for establishing an at least temporary electrical connection between the vehicle (110) and the power grid (120).