WO2012013414A2

WO2012013414A2 - Charging system for an energy store

Info

Publication number: WO2012013414A2
Application number: PCT/EP2011/059887
Authority: WO
Inventors: Thomas Komma; Jürgen RUPP; Armin Schlereth; Stefan VÖLKEL
Original assignee: Siemens Aktiengesellschaft
Priority date: 2010-07-28
Filing date: 2011-06-15
Publication date: 2012-02-02
Also published as: WO2012013414A3; DE102010032491A1

Abstract

The invention relates to a charging system comprising an energy store (7) for storing electric energy and a charger (6) to be connected in a three phase manner for charging the energy store from a three-phase supply network (1, 2, 3), wherein the charger (6) has a power factor correction filter and the direct voltage output by the charger lies above the peak voltage of the supply network, and wherein the input voltage of the energy store lies in the range of the direct voltage output by the charger (6), wherein said charging system further comprises means (10, 20-23, 30, 31, 40, 41) for charging the energy store from a state of deep discharge to a state in which the charger (6) can be used to carry out further charging.

Description

description

The invention relates to a charging system for an energy store for storing electrical energy, in particular for use in electrically powered vehicles.

For electrically powered vehicles with energy storage (= accumulator, battery), a device for charging this memory is necessary. For future electrically powered vehicles, the energy storage devices will be able to absorb very large amounts of energy in order to provide an acceptable range for the electrically powered vehicles.

In order to be able to load these large amounts of energy into the energy storage device within an acceptable period of time, a high charging power is required in comparison to today's services in private households. Powerful, regulated rectifiers with power factor correction (PFC) filters are preferred. This procedural ^¬ ren requires at ordinary realization with backward nichtsper- in power semiconductors, that the voltage of the DC intermediate circuit is higher than the peak voltage of the storage send supply network. For the overall efficiency, it is again advantageous then to make an interpretation of Energiespei ^¬ chers to a voltage level above the peak voltage of the supply network. This eliminates the Notwen ^¬ speed additional electronics between the rectifier and the energy store.

The disadvantage here is that the charging device can not be used if the battery voltage drops, for example, in a deep discharge below the peak voltage. Then very high currents would flow through the anti-parallel diodes and destroy them if necessary. A deeply discharged in the manner described battery can be charged, for example, with an external auxiliary charger so far ^¬ again until the voltage is high enough. Then the charging can be continued with the regulated rectifier. But that is not on ^¬ consuming and the user of an electric vehicle practicable depending on the structure of the vehicle.

It is the object of the present invention to specify a charging system which avoids the mentioned disadvantage, that is, in particular allows charging even from a state of deep discharge. In particular, the efficiency in the charge of the energy storage in the normal state should not be deteriorated. Further, a charging method for a charge of the energy storage of a state of deep discharge ^¬ out to be specified.

This object is achieved by a charging system having the features of claim 1. Another solution consists in the method with the features of claim 10. The dependent claims relate to advantageous embodiments of the invention.

The charging system according to the invention for charging an energy storage ^¬ memory for storing electrical energy has a three-phase to be connected charger for charging the energy ^¬ giespeichers from a three-phase supply network. The charger has a power factor correction filter.

The output by the charger DC voltage is above the peak voltage of the supply network and the input ^¬ voltage of the energy storage in turn in the range of output from the charger DC voltage. The energy storage, for example, accumulator in an electrically operated ^¬ benen vehicle is preferably connected directly to the charger via voltage matching electronics.

In addition, according to the invention, means are provided which are deeper to ei ^¬ ner charging of the energy storage from a state Discharge serve and are designed. The energy storage is charged by the means into a state in which the charger is usable to perform another charge. The state of deep discharge is a state in which the input voltage of the energy store is verrin ^¬ siege such that charging with the charger is no longer possible without damaging the electronics.

For the invention it was recognized that it is advantageous to the charger, which together with the energy storage on high

Efficiency at high power is designed to set aside the means for auxiliary charging. This ensures that ei ^¬ ne recharging is possible without external aids in a deep discharge of the energy storage. In an electric car, for example, a recharge is possible even with deeply discharged battery, without the need for an external auxiliary charger must be provided.

The means are preferably configured to supply a DC voltage below the peak voltage of the supply network to the energy store. In other words, the means may deliver a voltage lower than the voltage that the charger can produce. The voltage can thereby be adapted to the reduced input voltage of the energy storage. Thereby, the flowing in Aufla ^¬-making currents are reduced and a more secure Ladebe ^¬ operating permits.

Preferred, but in no way limiting Ausführungsbei games for the invention will now be described with reference to the drawings. The features are shown schematically Darge and corresponding features are marked with the same Be ^¬ zugszeichen. Hereby show in detail

Figure 1 is a charger with a single-phase connected

Auxiliary charger,

2 shows a charger with a bridgeable buck converter as an auxiliary charging system, Figure 3 shows a charger with a variable connection to the phases of the supply network, and

Figure 4 shows a charger with a variable connection to the phases of the supply network with additional current limit.

Figure 1 shows a first embodiment of a Ladesys ^¬ system for a secondary battery 7. Figure 1 shows a low-voltage supply network, which comprises three phase lines 1, 2, 3 environmentally. Furthermore, the low-voltage power supply network comprises a neutral conductor 4 and the protective conductor 5.

A charger 6 is connected to the three phase lines 1, 2, 3 of the low-voltage supply network. The charging device 6 is shown only schematically. It has an Leis ^¬ factor correction filter. It is connected by connecting lines 8, 9 directly to the accumulator 7.

The DC voltage output by the charger 6 is higher than the peak voltage of the supply network and the A ^¬ output voltage of the battery 7 is again in the range of the DC voltage outputted from the charger. 6

In addition, an auxiliary charging device 10 is provided in the first embodiment. This single phase is connected, ie the input side to the third phase line 3 and connected to the Neut ^¬ ralleiter. 4 On the output side, the auxiliary charger 10 as well as the charger with the connecting lines 8, 9 is connected. The auxiliary charger 10 provides a DC voltage on the connection lines 8, 9, if necessary, ie with deeply discharged accumulator 7. This DC voltage is lower than the DC voltage that can be generated by the charger 6. The charger 6 has a Steue ^¬ tion device not shown in Figure 1, which controls, for example, the circuit of the power electronic switching elements in the rectifier of the charger. This control device also controls if the auxiliary charger 10. The control device may, for example, measuring means for determining the voltage of the accumulator 7 have. If the voltage of Akkumu ^¬ lators 7 falls, for example, a first determinable

Threshold, so there is a deep discharge. In this case, the controller ensures that not the charger 6, son ^¬ dern the auxiliary charger 10, a voltage on the connection ^¬ lines 8, 9 imprints. As a result, a charge of the accumulator 7 is made. If the voltage of the accumulator 7 reaches a second definable threshold value, which may also be equal to the first definable threshold value, the control device switches off the auxiliary charger 10 and the charger 6. The charging is then continued by the charger ^¬ device 6 with increased power and better efficiency than the auxiliary charger 10.

A particular advantage results in the described embodiment, if no three-phase power supply is available for charging. In this case, the controller causes the charging is carried out independently of the voltage level of Akkumu ^¬ lator 7 from the auxiliary charger 10. This ar ^¬ beitet with a better efficiency than the charger 6, when only a low-performance network connection is available.

A further possibility of the implementation shows a two ^¬ tes embodiment, which is shown in Figure 2. In the second embodiment, the components of Nie ^¬ derspannungs supply network, ie the phase lines 1 ... 3, the neutral conductor 4 and protective conductor 5 are also present. In addition, the charger 6 and the accumulator ^¬ tor 7 are again present, which are connected according to the first Ausführungsbei ^¬ game. The auxiliary charger 10 is not provided in the two ^¬ th embodiment.

In the second embodiment, an intermediate circuit capacitor 23 is provided parallel to the accumulator 7. In a first of the connecting lines 8 to the accumulator 7 is a first Switch 22 is provided for separating this connection. Furthermore, a series circuit ^¬ tion of a second switch 21 and a buck converter 20 is arranged parallel to the first switch. Both the first switch 22 and the series circuit are arranged electrically between the intermediate circuit capacitor 23 and the accumulator 7, ie the connection of the accumulator 7 and the intermediate circuit capacitor 23 via the first connection line 8 can be separated by the first switch 22 ,

In the second exemplary embodiment, the first switch 22 is closed and the second switch 21 is opened for a charging of the accumulator 7 by the charger, that is, in a non-low ^¬ discharged state. As a result, the charger 6 is connected directly to the accumulator 7, the intermediate-circuit capacitor 23 being connected in parallel.

In the event of a deep discharge of the accumulator 7, however, the first switch 22 is opened and the second switch 21 is closed. In this case, therefore, the accumulator 7 via the

Buck converter 20 is connected and is loaded via this. The charger 6 charges in this case, only the DC link capacitor 23. The buck converter 20 is controlled so that the voltage present at the accumulator 7 voltage is so reduced counter to the normal charging voltage that si ^¬ chere charge can take place.

Again, the control device controls the charger and the first and second switches 22, 21 and the buck converter 20. As in the first embodiment, it is useful if the controller can determine the voltage of the battery 7. If the voltage of Akkumu ^¬ lators 7 falls, for example, a first determinable

Threshold, so there is a deep discharge. In this case, the controller switches the first and second

Switch 22 so that the buck converter 20 is connected to the accumulator 7 and controls the buck converter 20 accordingly. When the voltage of the accumulator 7 reaches second definable threshold value, which may also be equal to the first definable threshold value, the control device switches off the ^buck converter 20. The charge is then continued without detour via the buck converter 20, which then typically has a better efficiency.

Another variant, different from the first exemplary embodiments, is shown with reference to FIG. In the third variant, the components of low-voltage supply network, ie the phase lines 1 ... 3, the Neutrallei ^¬ ter 4 and earth conductor 5 is also present. In addition, the charger 6 and the accumulator 7 are again present, which are connected according to the first embodiment.

In the third variant, the connection to the corresponding phase line 1... 3 of the supply network can be disconnected in at least one of the inputs of the charger 6, and a connection to the neutral conductor 4 of the supply network can be established. For this purpose, a first switching device 30 is provided in the third embodiment, with which the connection of all the phase lines 1 ... 3 to the charger 6 is interruptible together. Furthermore, a bridging of the first switching device 30 is provided for one of the phase lines 1... 3, in this example the third phase line 3. Another of the phase lines 1... 3, in this example the second phase line 2, is additionally connected to the neutral conductor 4. The connection to the neutral conductor 4 and the bridging can be separated together via a second switching device 31. In this case, because of the lower power that passes through the second switching device 31, these are made smaller than the first switching device 30th

In the third embodiment, a normal charge of the accumulator 7 is made by the first switching device 30 connects the charger 6 to the supply network and the second switching device 31 separates their respective connections. In the case of depth Charge of the accumulator 7, the switching state of the two switching devices 30, 31 is reversed. In this case, so the three-phase connection of the charger 6 is repealed. Instead ^¬ which is a single-phase connection of the charger 6 Siert realized. Due to the correspondingly reduced input voltage, a voltage reduced by a factor of 1.7 can also be generated on the connection lines 8, 9. As a result, therefore, a charge of the battery is possible, provided that the reduced by a factor of 1.7 voltage is permitted as the charging voltage.

The described embodiment assumes that the individual contacts of the first switching device 30 can only be switched together. If, on the other hand, the contacts can be switched individually, one of the contacts at the location of the

Bridging be used. In this case, the second switching device 31, instead of two-pole executed who ^¬ . A fourth embodiment indicates an improvement of the third embodiment. The fourth Ausführungsbei ^¬ game is shown in Figure 4 and includes the components of the third embodiment. It is again assumed that the individual contacts of the first switching device 30 can only be switched together.

In addition, a current limiting resistor 41 is provided in the bypass. This allows charging, even if the battery 7 is discharged very deeply and therefore its voltage has dropped well below the reduced by a factor of 1.7 voltage. In addition, in this embodiment parallel to the switching contact of the second switching device ^¬ 31 and the current limiting resistor 41, a third switching device 40 is provided. With the aid of the third switching device 40, in turn, the current limiting resistor 41 can be bridged. The control device will thus determine the voltage of the accumulator 7 in the fourth embodiment. If this is below a first load threshold value, which is expediently divided in Be ^¬ reaching the normal voltage of the battery 7 by 1.7, so a charge is made, where the Kontakt ^¬ te of the first and third switching means 30, 40 separated and the the second switching device 31 are connected. It is therefore made a charging with single-phase of the charger 6, wherein the maximum current flowing through the current limiting resistor 41 is reduced so much that damage to the electronic components is avoided. If the voltage of the battery 7 via the first load threshold value, the contacts of the third switching device 40 are connected ^¬. As a result, there is a function as in the third embodiment. It is therefore still a charge with single-phase of the charger 6 made, with a current limit is no longer provided.

If the voltage of the accumulator exceeds a second charging threshold, it is switched to the normal charging mode. Thus, the contacts of the first switching device 30 are connected and those of the second and third switching devices 31, 40 are disconnected. As a result, the charger is thus dreipha ^¬ sig connected and can work with provided power and efficiency.

Claims

claims

1. charging system, comprising:

- An energy store (7) for storing electrical

Energy,

a charger (6) to be connected in three phases for charging the energy store (7) from a three - phase supply network, the charger (6) having a power factor correction filter and the DC voltage output by the charger (6) above the peak voltage of the

Supply network is located, and wherein the input voltage of the energy store (7) in the range from the charger (6) from ^¬ given DC voltage,

- With means (10, 20 ... 23, 30, 31, 40, 41) for charging the energy store (7) from a state of deep discharge in a state in which the charger (6) is usable, ei ^¬ ne further To perform charging.

2. Charging system according to claim 1, wherein the means (10, 20 ... 23, 30, 31, 40, 41) are designed for charging, ei ^¬ ne DC voltage below the peak voltage of the supply network to the energy storage (7) to deliver ,

3. charging system according to claim 1 or 2, wherein the means (10, 20 ... 23, 30, 31, 40, 41) are designed for charging as a single phase connected to the supply network auxiliary charger (10) from ^¬ , wherein the auxiliary charger (10) on the output side to the input terminals (8, 9) of the energy store (7) are connected.

4. Charging system according to claim 1 or 2, comprising an intermediate circuit capacitor (23) between the energy store (7) and the charger (6) and in which the means (10,

20 ... 23, 30, 31, 40, 41) for charging a buck converter (20) between the energy store (7) and the intermediate circuit capacitor (23) and switch means (22) for elec ^¬ tronic bridging the buck converter.

5. charging system according to claim 1 or 2, configured such that for charging the energy store (7) from a state of deep discharge for at least one of the inputs of the charging device ^¬ (6) the connection with the corresponding phase

(1 ... 3) of the supply network separable and a connection to the neutral conductor (4) of the supply network can be produced.

6. charging system according to claim 5, wherein for at least one of the inputs of the charger (6), a current limiting resistor (41), which in particular by a switching means (40) can be bridged, is provided.

7. A method for charging an energy store (7) for storing electrical energy from a state of deep discharge, wherein the input voltage of the energy store (7) is lowered by the state of deep discharge, in which

- a to the reduced input voltage of the Energiespei ^¬ Chers (7) adapted dc voltage at the inputs (8, 9) of the energy store (7) is applied, and ^¬ the energy store (7) is loaded into the next thereby until its input voltage a achievable threshold,

- A further charge of the energy storage device (7) by a three-phase to be connected charger (6) for charging the energy storage device (7) is made from a three-phase supply network, wherein a power ^{factor correction} filter is used and by the charger (6) a DC voltage greater than that Peak voltage of the supply network is output and this DC voltage to the inputs (8, 9) of the energy storage (7) is applied.

8. The method according to claim 7, wherein the adapted DC voltage is generated by a single-phase connected auxiliary charger (10).

9. The method according to claim 7, wherein a DC link capacitor (23) between the energy store (7) and the charger (6) is used and the adapted DC voltage is generated by a step-down converter (20) between the energy store (7) and the DC link capacitor (23), wherein the step-down converter (20) is electrically bridged when the input voltage of the energy store (7) reaches the threshold value.

10. The method according to claim 7, wherein for charging the energy store (7) from a state of deep discharge for at least one of the inputs of the charger (6) the connection with the corresponding phase (1 ... 3) of the Versorgungsnet ^¬ zes is separated and a connection with the Neutrallei ^¬ ter (4) of the supply network is produced.