Charging system

Abstract

A charging system has: a number of connections for connecting at least one electric energy store to be charged; a number n of at least three inverter bridges, each of which has a center tap; a number n of electric filters, wherein the input of each filter of the number n of filters is electrically connected to a respective corresponding center tap of an inverter bridge of the number of inverter bridges; a controllable assigning unit which is inserted between a respective output of a filter of the number n of filters and the number of connections and which is designed to electrically assign the output of each filter of the number n of filters to a respective corresponding connection of the number of connections depending on at least one actuation signal; and a control unit which is designed to generate the at least one actuation signal depending on a desired charge mode of the charging system.

Claims

1. A charging system, comprising: a number m of connections for connecting at least one electric energy accumulator to be charged; a number n of at least three inverter bridges, each of which comprises a center tap; a number n of electrical filters, wherein one input of a respective filter of the number n of filters is electrically connected to a respectively associated center tap of an inverter bridge of the number n of inverter bridges; a controllable assigning unit, which is interpolated between a respective output of one filter of the number n of filters and the number m of connections and is designed, depending upon at least one actuation signal, to electrically assign a respective output of one filter of the number n of filters to a respectively associated connection of the number m of connections; and a control unit, which is designed to generate the at least one actuation signal, in accordance with a desired charging mode of the charging system, wherein the charging system comprises modes of: (a) simultaneous charging of a plurality of electric energy accumulators with alternating current, (b) charging of at least one energy accumulator with alternating current, wherein a charging current in charging mode (b) is higher than a charging current in charging mode (a), (c) simultaneous charging of a plurality of electric energy accumulators with direct current, (d) charging of at least one electric energy accumulator with direct current, wherein a charging current in charging mode (d) is higher than a charging current in charging mode (c), and wherein the desired charging mode is selected from one of: (a), (b), (c), or (d).

2. The charging system according to claim 1, further comprising: an energy supply accumulator which is designed to electrically supply the number n of inverter bridges.

3. The charging system according to claim 1, wherein a respective filter of the number n of filters comprises at least one reactance coil and a capacitor.

4. The charging system according to claim 2, wherein the control unit is designed to generate the at least one actuation signal for the controllable assigning unit and further actuation signals for switching devices of the inverter bridges, such that the energy supply accumulator is charged by way of electrical energy which is made available on one or more connections of the number m of connections.

5. The charging system according to claim 2, wherein the control unit is designed to generate the at least one actuation signal for the controllable assigning unit and further actuation signals for switching devices of the inverter bridges, such that electrical energy which is stored in the energy supply accumulator is injected into an electricity supply grid, which is connected to one connection or a plurality of connections of the number m of connections.

6. The charging system according to claim 2, wherein the energy supply accumulator supplies a voltage at a level which is higher than the level of a voltage which is delivered by a charging energy accumulator.

7. The charging system according to claim 1, wherein the assigning unit comprises a number of actuatable switching devices.

8. The charging system according to claim 7, wherein the actuatable switching devices are contactors.

9. The charging system according to claim 4, wherein the control unit is designed to generate the at least one actuation signal for the controllable assigning unit and further actuation signals for switching devices of the inverter bridges, such that electrical energy which is stored in the energy supply accumulator is injected into an electricity supply grid, which is connected to one connection or a plurality of connections of the number m of connections.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows a block diagram of an outline layout of a charging system according to the invention.

(2) FIG. 2 shows a number of inverter bridges of the charging system represented in FIG. 1, according to a first embodiment.

(3) FIG. 3 shows a number of inverter bridges of the charging system represented in FIG. 1, according to a further embodiment.

(4) FIG. 4 shows a number of electrical filters of the charging system represented in FIG. 1.

(5) FIG. 5 shows a controllable assigning unit of the charging system represented in FIG. 1, according to a first embodiment.

(6) FIG. 6 shows a controllable assigning unit of the charging system represented in FIG. 1, according to a further embodiment.

(7) FIG. 7 shows the charging system in a first charging mode.

(8) FIG. 8 shows the charging system in a second charging mode.

(9) FIG. 9 shows the charging system in a third charging mode.

DETAILED DESCRIPTION OF THE DRAWINGS

(10) FIG. 1 shows a block diagram of an outline layout of a charging system 1. The charging system 1 can be a portable charging system which, for example, can be arranged in a motor vehicle, for example in the form of a private car.

(11) The charging system 1 comprises an optional electrical energy supply accumulator 3 in the form of a battery, which delivers an operating voltage of approximately 800 V.

(12) The charging system 1 further comprises a number m of connections 12_1, . . . , 12_m for the connection of electric energy accumulators 2 to be charged. The electric energy accumulators 2 can be, for example, batteries of at least partially electrically-propelled motor vehicles.

(13) One or more connections of the number m of connections 12_1, . . . , 12_m can also be connected to an electricity supply grid 21 wherein, in this case, electrical energy from the energy supply accumulator 3 can be injected into the electricity supply grid 21 or, conversely, electrical energy from the supply grid 21 can be injected into the energy supply accumulator 3.

(14) In the present exemplary case, two electric energy accumulators 2 are represented, which can simultaneously be charged by means of the charging system 1, as described in greater detail hereinafter. It is understood that, depending upon the dimensioning of the charging system 1, more than two electric energy accumulators 2 can also be charged simultaneously.

(15) For example, the charging system 1, in a first exemplary dimensioning stage, can comprise m=8 connections 12, of which four connections respectively can be combined in a plug-in connector.

(16) The charging system 1 further comprises an inverter unit 5 which, with reference to FIGS. 2 and 3, comprises a number n of at least three inverter bridges 5_1, . . . 5_n. In the forms of embodiment represented, the number n, for example, can be 6.

(17) With reference to FIG. 2, each of the inverter bridges 5_1, . . . , 5_n comprises two actuatable semiconductor switching devices 15, which are series-connected between poles 16 and 17. The semiconductor switching devices 15 are actuated by means of actuation signals C1 to Cp, wherein the actuation signals C1 to Cp are generated by a control unit 20. A positive intermediate circuit potential is present on pole 16, and a negative intermediate circuit potential is present on pole 17, wherein the potential difference between the two poles 16, 17 constitutes an intermediate circuit voltage VB, which is buffered by means of an intermediate circuit capacitor 4. This intermediate circuit voltage VB is that voltage which is output by the electrical energy accumulator 3 or the battery. In consequence, the respective inverter bridges 5_1, . . . 5_n are supplied from the energy supply accumulator 3.

(18) Alternatively or additionally to the supply of the inverter bridges 51, . . . , 5_n from the energy supply accumulator 3, the intermediate circuit voltage can also be generated by means of an unrepresented electric generator which, for example, can be driven by a combustion engine of a motor vehicle or private car.

(19) The inverter bridges 5_1, . . . , 5_n respectively comprise a center tap 10_1, . . . 10_n, which corresponds to an electrical connection point of the respective semiconductor switching devices 15.

(20) The inverter unit 5 represented in FIG. 3 comprises inverter bridges 51, . . . , 5_n, each having four actuatable semiconductor switching devices 15, which are series-connected between the poles 16 and 17. It is understood that any respective inverter bridge can also comprise more than four semiconductor switching devices.

(21) With reference to FIG. 4, the charging system 1 further comprises a filter unit 6 having a number n of electrical filters 6_1, . . . , 6_n. A respective electrical filter 6_1, . . . , 6_n comprises an input 131, . . . , 13_n. A respective input 13_1, . . . , 13_n is electrically connected to a respectively associated center tap 101, . . . , 10_n of one of the inverter bridges 5_1, . . . , 5_n. This means that the input 131 is connected to the center tap 101, the input 132 is connected to the center tap 10_2, etc.

(22) A respective filter 6_1, . . . , 6_n comprises two reactance coils 7 and a capacitor 14 in a PI topology.

(23) With reference to FIGS. 1, 5 and 6, the charging system 1 further comprises a controllable assigning unit 8 which is interpolated between the outputs 11_1, . . . , 11_n of the filters 6_1, . . . , 6_n and the connections 12_1, . . . , 12_m.

(24) The controllable assigning unit 8 is designed, according to a number k of actuation signals AS_1, . . . , AS_k, to electrically connect a respective output 11_1, . . . , 11_n of a filter 6_1, . . . , 6_n with one of the respectively associated connections 12_1, . . . , 12_m, in a manner which will be described in greater detail hereinafter. The number k can be equal to the number n, or equal to the number m, or different from n and m.

(25) The control unit 20 of the charging system 1 is designed to generate the actuation signals AS_1, . . . , AS_k in accordance with a desired charging mode of the charging system 1.

(26) With reference to FIGS. 5 and 6, the assigning unit 8 comprises a number of actuatable switching devices 9 in the form of contactors, which are actuated by the control unit 20 in accordance with a desired charging mode of the charging system 1, and which assume a charging mode-dependent circuit state.

(27) The circuit state of the actuatable switching devices 9 is appropriately set by means of the actuation signals AS_1, . . . , AS_k. The number k of actuation signals AS_1, . . . AS_k can be identical to the number of switching devices.

(28) By means of the charging system 1, in a first charging mode, for example, two electric energy accumulators 2 can be simultaneously charged with alternating current. The electric energy accumulators 2 can simultaneously be charged in three phases, can simultaneously be charged in a single phase or, in a mixed arrangement, one of the electric energy accumulators 2 can be charged in three phases, and the other electric energy accumulator 2 can be charged in a single phase.

(29) FIG. 7 shows a schematic representation of the charging system 1 in the first charging mode, with the corresponding circuit state of the switching devices 9 of the controllable assigning unit 8. The assigning unit and the switching devices 9 thereof, in the interests of greater clarity, are not represented here, but only the resulting electrical associations of filter outputs with the connections 12_1 to 12_6. In this case, for exemplary purposes, each of the filters 6_1 to 6_6 comprises only one reactance coil 7.

(30) The circuit states of the switching devices 9 of the controllable assigning unit 8 are selected such that the bridge arms 5_1 to 5_3 constitute a first three-phase inverter which, from the DC voltage supplied by the electrical energy supply accumulator 3, conventionally generates a three-phase AC charging voltage, which is outputted at the connections 12_1 to 12_3, and can be employed for the three-phase charging of a first electric energy accumulator 2. An optional connection 18 is further provided, which is connected to PE.

(31) The circuit states of the switching devices 9 of the controllable assigning unit 8 are further selected such that the bridge arms 5_4 to 5_6 constitute a second three-phase inverter which, from the DC voltage supplied by the electrical energy supply accumulator 3, conventionally generates a three-phase AC charging voltage, which is outputted at the connections 12_4 to 12_6, and can be employed for the three-phase charging of a second electric energy accumulator 2. An optional connection 19 is further provided, which is connected to PE.

(32) The connections 12_1, 12_2, 12_3 and 18 can be integrated in a plug-in connector. Correspondingly, the connections 12_4, 12_5, 12_6 and 19 can be integrated in a further plug-in connector.

(33) FIG. 8 shows a schematic representation of the charging system 1 in a second charging mode, with the corresponding circuit state of the switching devices 9 of the controllable assigning unit 8. The assigning unit and the switching devices 9 thereof, in the interests of greater clarity, are not represented here, but only the resulting electrical associations of filter outputs with the connections 12_1 to 12_3. In this case, for exemplary purposes, each of the filters 6_1 to 6_6 comprises only one reactance coil 7.

(34) In the second charging mode, a single electric energy accumulator 2 can be charged with alternating current, wherein a charging current is higher than a charging current in the first charging mode.

(35) In the second charging mode, two bridge arms respectively are connected via a corresponding filter to a common associated connection, i.e. are parallel-connected such that, in relation to the first charging mode, a higher charging current output is permitted. Accordingly, the bridge arms 5_1 and 5_4 are connected by means of their filters 6_1 or 6_4 to the connection 12_1, the bridge arms 5_2 and 5_5 are connected by means of their filters 6_2 or 6_5 to the connection 122, and the bridge arms 5_3 and 5_6 are connected by means of their filters 6_3 or 6_6 to the connection 12_3.

(36) FIG. 9 shows a schematic representation of the charging system 1 in a third charging mode, with a corresponding circuit state of the switching devices 9 of the controllable assigning unit 8. The assigning unit and the switching devices 9 thereof, in the interests of greater clarity, are not represented here, but only the resulting electrical associations of filter outputs with the connections 12_1 and 12_2. In this case, for exemplary purposes, each of the filters 6_1 to 6_6 comprises only one reactance coil 7.

(37) In the third charging mode, a single electric energy accumulator 2 can be charged with direct current to a maximum charging capacity.

(38) In the third charging mode, the upper semiconductor switching devices 15 of the three bridge arms 5_1, 5_2, 5_3 are permanently conducting, and the lower semiconductor switching devices 15 of the three bridge arms 5_1, 5_2, 5_3 are permanently non-conducting. Accordingly, the pole 16 or the positive intermediate circuit potential is electrically connected via the upper switching devices 15 of the three bridge arms 5_1, 5_2, 5_3 and the reactance coils 7 of the filters 6_1, 6_2 and 6_3 to the connection 12_1.

(39) Correspondingly, the upper semiconductor switching devices 15 of the three bridge arms 5_4, 5_5, 5_6 are permanently non-conducting, and the lower semiconductor switching devices 15 of the three bridge arms 5_4, 5_5, 5_6 are permanently conducting. Accordingly, the pole 17 or the negative intermediate circuit potential is electrically connected via the lower switching devices 15 of the three bridge arms 5_4, 5_5, 5_6 and the reactance coils 7 of the filters 6_4, 6_5 and 6_6 to the connection 12_2.

(40) If the power flux is reversed, the inverter unit 5 can also be employed for the recharging of the electrical energy supply accumulator 3. To this end, the control unit 20 can generate the actuation signals AS_1, . . . , AS_k for the controllable assigning unit 8 and the further actuation signals C1, . . . , Cp for the semiconductor switching devices 15, such that the energy supply accumulator 3 is charged by means of electrical energy which is made available on one or more of the connections 12_1, . . . , 12_m.

(41) The control unit 20 can be designed to generate all actuation signals such that a zero-current switching of the switching devices 9 of the assigning unit 8 is permitted, as a result of which the switching devices 9 can be dimensioned with a low switching capacity.

(42) Additionally, overload protection of the switching devices 9 can be achieved by means of integrated current measurement in the inverter bridges.

(43) The control unit 20 can be configured for communication with the energy supply accumulator 3 and all the connected electric energy accumulators 2, and can control the inverter unit 5 such that the required power (voltage and current) is delivered.

(44) According to the invention, by the parallel connection of bridge arms as required, an AC charging current can be increased, as a result of which a rapid charging of electric vehicle energy accumulators is permitted. Correspondingly, by the parallel connection of bridge arms, a DC charging current can be increased.

(45) The charging system according to the invention further permits the recharging of the energy supply accumulator 3 using a conventional three-phase industrial socket connection.