CN107852086B

CN107852086B - Multi-phase inverter

Info

Publication number: CN107852086B
Application number: CN201680043954.8A
Authority: CN
Inventors: T.延拜因
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2015-07-28
Filing date: 2016-07-06
Publication date: 2020-03-03
Anticipated expiration: 2036-07-06
Also published as: DE102015214276A1; WO2017016828A1; CN107852086A; EP3329582A1

Abstract

The invention relates to a multiphase inverter (10) for controlling a multiphase consumer (50), comprising: a plurality of input terminals (25, 26, 27, 28) for connecting at least one first battery pack (21) and at least one second battery pack (22); and a plurality of phase outputs (51, 52, 53) for connecting the consumers (50), wherein each phase output (51, 52, 53) is assigned a bridge circuit (31, 32, 33) having an actuatable switch (S1, S2, S3, S4, S5; S6, S7, S8, S9, S10; S11, S12, S13, S14, S15), by means of which bridge circuit the phase outputs (51, 52, 53) can be connected to different input terminals (25, 26, 27, 28). Here, each bridge circuit (31, 32, 33) has: an input switch (S1; S6; S11) which is connected to the first input connection (25) and to the phase output (51, 52, 53); a plurality of node switches (S2, S3, S5; S7, S8, S10; S12, S13, S15) which are connected to the remaining input terminals (26, 27, 28) and to the nodes (41, 42, 43); and an output switch (S4; S9; S14) connected to the node (41, 42, 43) and to the phase output (51, 52, 53).

Description

Multi-phase inverter

Technical Field

The invention relates to a multiphase inverter for controlling a multiphase consumer, comprising: a plurality of input terminals for connecting at least one first battery pack and at least one second battery pack; and a plurality of phase outputs for connection to the electrical consumers.

Background

For controlling polyphase consumers, for example three-phase motors, it is known to use inverters. Such an Inverter is also called a converter (Inverter). The inverter enables the electrical consumers to be supplied with current from a direct voltage source, for example a battery.

Inverters are used in particular in motor vehicles for controlling three-phase motors. Inverters are also used, for example, for feeding the current generated in photovoltaic installations into existing power supply networks.

Inverters to which a plurality of battery packs, for example two battery packs, can be connected are known. In the case of a corresponding activation of the inverter, the load can be selectively fed by the first battery, by the second battery or by a series circuit of two batteries. Thereby, the electrical consumers can be supplied with voltages that are not equally high. Such inverters are also referred to as Multilevel converters (Multilevel-inverters).

Such an inverter is known from DE 102012012048 a 1. Here, the inverter includes: a plurality of input terminals to which two capacitors are connected; and three phase output terminals for connecting the alternating current motor. In this case, a bridge circuit having an actuatable switch is assigned to each of the three phase outputs, by means of which bridge circuit the respective phase output can be connected to a different input connection.

DE 102012212556 a1 discloses a circuit with a controllable switch and with two phase outputs. By corresponding manipulation of the switches, three different voltages can be set between the phase outputs.

An energy storage device with two phase outputs is known from DE 102013215572 a 1. The energy storage device has a plurality of multi-stage converters, which are also referred to as multi-stage converters.

DE 102011056135 a1 discloses an energy generating device having a generator and an inverter. The inverter is designed as a multi-stage inverter.

Disclosure of Invention

A multiphase inverter for operating a multiphase consumer is proposed. The inverter includes: a plurality of input terminals for connecting at least one first battery pack and at least one second battery pack; and a plurality of phase outputs for connection to the electrical consumers. In this case, a bridge circuit with controllable switches is assigned to each phase output, by means of which bridge circuit the phase outputs can be connected to different input terminals.

According to the invention, each bridge circuit has an input switch, a plurality of node switches and an output switch. The input switches of each bridge circuit are connected to the first input connection and to the phase outputs. The node switch of each bridge circuit is connected to one of the other input terminals and to a node. The output switches of each bridge circuit are connected to the nodes and to the phase outputs. Therefore, the phase output end can be selectively connected with the first input end wiring terminal and the node.

Preferably, three phase outputs are provided for connecting a three-phase consumer, for example an ac motor.

The switch at least comprises a transistor, a diode and a control unit. The diode is connected to the transistor in such a way that a current can flow in a predetermined direction even if the transistor is switched off. The transistor is preferably a bipolar transistor or an Insulated Gate Bipolar Transistor (IGBT).

Preferably, a first input terminal and a second input terminal for connecting a first battery pack are provided, and a third input terminal and a fourth input terminal for connecting a second battery pack are provided.

Advantageously, the inverter is configured such that: in the case of an open switch, the first and second input connection terminals are galvanically isolated from the third input connection terminal and from the fourth input connection terminal.

Each bridge circuit has, in particular, a primary node switch, which is connected to the second input connection and to a node. Thus, the primary node switch is connected to the first battery pack, as is the input terminal switch.

According to an advantageous embodiment of the invention, the primary node switches are designed as anti-parallel switches and each comprise two transistors, two diodes and a control unit. Here, the diode is connected to the transistor in such a way that no current can flow in any direction if the transistor is switched off.

Advantageously, the inverter is configured such that: if both battery packs are connected, the first battery pack is galvanically isolated from the second battery pack with the switch open.

Advantageously, the inverter according to the invention is used in an Electric Vehicle (EV), in particular for operating a three-phase electric machine, in a Hybrid Electric Vehicle (HEV), in a plug-in hybrid electric vehicle (PHEV) or in a photovoltaic system. The inverter according to the invention can in principle be used in all areas if two battery packs are to be connected.

THE ADVANTAGES OF THE PRESENT INVENTION

In the case of a corresponding activation of the inverter according to the invention, the connected consumers can be selectively fed by the first battery, by the second battery or by a series circuit of two batteries. Thereby, connected consumers can be supplied with voltages that are not as high. The inverter according to the invention thus has the functionality of a multi-stage converter.

In addition, the connected electrical loads can also be fed by a parallel circuit of two battery packs with corresponding activation of the inverter according to the invention. As a result, a higher current can be supplied to the connected consumers when the voltages are the same.

In the case of a parallel circuit of two battery packs for feeding a connected consumer, the voltage of the first battery pack is allowed to be greater than the voltage of the second battery pack. The electrical load is first of all fed only by the first battery pack, which has a higher voltage and thus also a higher charge state. The connected consumers are only fed by the two battery packs when the first battery pack is discharged to approximately the same extent as the state of charge of the two battery packs.

Therefore, in the case of such a parallel circuit of a first battery pack having a higher state of charge and a second battery pack having a lower state of charge, the first battery pack is first discharged to the extent that: until the state of charge of the two battery packs is approximately equalized. Then, both battery packs are discharged approximately equally. Therefore, when the connected load is fed by the parallel circuit of two battery packs, the state of charge is automatically equalized, which is also referred to as Balancing.

Drawings

Embodiments of the invention are further illustrated in the accompanying drawings and the description that follows.

Wherein:

fig. 1 shows a schematic diagram of a multiphase, in particular three-phase, inverter;

FIG. 2 shows a schematic diagram of switches from the inverter of FIG. 1; while

Fig. 3 shows a schematic diagram of a primary node switch from the inverter of fig. 1.

Detailed Description

In the following description of embodiments of the invention, identical or similar elements are denoted by identical reference numerals, wherein in individual cases a repeated description of these elements is omitted. The figures only schematically show the subject matter of the invention.

Fig. 1 shows a schematic illustration of a polyphase, in particular three-phase, inverter 10. The inverter 10 comprises a first input connection terminal 25, a second input connection terminal 26, a third input connection terminal 27 and a fourth input connection terminal 28.

The positive pole of the first battery pack 21 is connected to the first input terminal 25. The negative electrode of the first battery pack 21 is connected to the second input terminal 26. The positive pole of second battery pack 22 is connected to third input terminal 27. The negative pole of the second battery pack 22 is connected to a fourth input terminal 28.

The first battery pack 21 provides a first battery pack voltage UB1, which is attached between the first input connection terminal 25 and the second input connection terminal 26 as a first battery pack voltage UB 1. Second battery 22 provides a second battery voltage UB2, which second battery voltage UB2 is attached between third input connection terminal 27 and fourth input connection terminal 28.

Furthermore, the inverter 10 has a first phase output 51, a second phase output 52 and a third phase output 53. The load 50 is connected to the phase outputs 51, 52, 53. In the present case, the load 50 is implemented three-phase and has a first phase 61, a second phase 62 and a third phase 63. In this case, a first phase 61 is connected to the first phase output 51, a second phase 62 is connected to the second phase output 52, and a third phase 63 is connected to the third phase output 53.

The first phase 61 of the load 50 comprises a load, which in the present case is represented by a series circuit of an inductance and an ohmic load. The second phase 62 likewise comprises a load which is present as a series circuit of an inductance and an ohmic load. The third phase 63 also comprises a load which is present as a series circuit of an inductance and an ohmic load. The

phases

61, 62, 63 of the consumer 50 are grouped together and connected to one another at the star point 60.

A first output voltage U1 drops between the first phase output 51 and the star point 60. A second output voltage U2 drops between the second phase output 52 and the star point 60. A third output voltage U3 drops between the third phase output 53 and the star point 60.

The first phase output 51 is assigned the first bridge circuit 31. The second phase output 52 is assigned the second bridge circuit 32. The third phase output 53 is assigned a third bridge circuit 33.

The first bridge circuit 31 comprises a first input switch S1, which first input switch S1 is connected to the first input connection 25 and to the first phase output 51. The second bridge circuit 32 comprises a second input switch S6, which second input switch S6 is connected to the first input connection 25 and to the second phase output 52. The third bridge circuit 33 comprises a third input switch S11, which is connected to the first input terminal 25 and to the third phase output 53 via a third input switch S11.

The first bridge circuit 31 comprises a first primary node switch S2, which is connected to the second input connection 26 and to the first node 41 via a first primary node switch S2. The second bridge circuit 32 comprises a second stage node switch S7, which is connected to the second input connection 26 and to the second node 42 via a second stage node switch S7. The third bridge circuit 33 comprises a third stage node switch S12, which is connected to the second input connection 26 and to the third node 43 via a third stage node switch S12.

The first bridge circuit 31 comprises a first diode switch S3, which is connected to the third input connection terminal 27 and to the first node 41 via a first diode switch S3. The second bridge circuit 32 comprises a second secondary node switch S8, which is connected to the third input connection 27 and to the second node 42 via a second secondary node switch S8. The third bridge circuit 33 comprises a third secondary node switch S13, which is connected to the third input connection 27 and to the third node 43 via a third secondary node switch S13.

The first bridge circuit 31 comprises a first three-stage node switch S5, which is connected to the fourth input terminal 28 and to the first node 41 via a first three-stage node switch S5. The second bridge circuit 32 comprises a second three-stage node switch S10, which is connected to the fourth input terminal 28 and to the second node 42 via a second three-stage node switch S10. The third bridge circuit 33 comprises a third three-stage node switch S15, which is connected to the fourth input terminal 28 and to the third node 43 via a third three-stage node switch S15.

The first bridge circuit 31 comprises a first output switch S4, which first output switch S4 is connected to the first node 41 and to the first phase output 51. The second bridge circuit 32 comprises a second output switch S9, the second output switch S9 being connected to the second node 42 and to the second phase output 52. The third bridge circuit 33 comprises a third output switch S14, which is connected to the third node 43 and to the third phase output 53 via a third output switch S14.

With a corresponding actuation of the switches S1 to S15, the connected electrical consumer 50 can be fed selectively by the first battery pack 21, by the second battery pack 22, and by the series circuit of the first battery pack 21 and the second battery pack 22. Likewise, with a corresponding actuation of the switches S1 to S15, the load 50 can be fed by a parallel circuit of the first battery pack 21 and the second battery pack 22. In this case, alternating output voltages U1, U2, U3 are supplied to the load 50, the alternating output voltages U1, U2, U3 having a phase difference with respect to one another.

Shown in tables 1 to 4 below, respectively: in which position the switches S1 to S15 connect which output voltage U1, U2, U3 to the

phase

61, 62, 63 of the load 50.

For all tables 1 to 4 apply:

1 switch closure

Idle switch off

D switch is off, but current passes through diode 81 in parallel with the switch

Table 1: the electrical load 50 is fed exclusively by the first battery pack 21. Then the following applies: u = UB1

Table 2: the consumer 50 is fed only by the second battery pack 22. Then the following applies: u = UB2

Table 3: the electrical load 50 is supplied by a series circuit of the first battery pack 21 and the second battery pack 22. Then the following applies: u = UB1 + UB2

Table 4: the load 50 is fed by a parallel circuit of the first battery pack 21 and the second battery pack 22. There are a number of variants.

As long as first battery voltage UB1 is approximately equal to second battery voltage UB2, a true parallel circuit exists. Then the following applies:

U = UB1 = UB2。

if first battery voltage UB1 is significantly greater than second battery voltage UB2, then no current passes through diode 81. The electrical load 50 is fed exclusively by the first battery pack 21. Then the following applies:

U = UB1。

if first battery voltage UB1 is significantly lower than second battery voltage UB2, then the parallel circuit formed by first battery 21 and second battery 22 is not permitted. In this case, a control unit, not shown here, prevents a corresponding actuation of the switches S1 to S15 of the inverter 10.

Fig. 2 schematically shows the structures of the input terminal switches S1, S6, S11, the output terminal switches S4, S9, S14, the secondary node switches S3, S8, S13, and the tertiary node switches S5, S10, S15. The switches mentioned each comprise a transistor 80, which transistor 80 is in this case implemented as a bipolar transistor. The transistor 80 includes a base B, an emitter E, and a collector C. The transistor 80 may also be implemented as an Insulated Gate Bipolar Transistor (IGBT), and in this case comprises a gate instead of the base B.

A diode 81 is connected in parallel between the emitter E and the collector C. The base B is connected to the control unit 82. By corresponding actuation by means of the actuation unit 82, the transistor 80 can be switched off or on. The switch concerned is opened or closed correspondingly.

The primary node switches S2, S7, S12 are shown in FIG. 3. Unlike the switches shown in fig. 2, the primary node switches S2, S7, S12 include first and

second transistors

80, 80 and first and

second diodes

81, 81.

In the present case, the two transistors are implemented as bipolar transistors and comprise a base B, an emitter E and a collector C, respectively. The transistor 80 may also be implemented as an Insulated Gate Bipolar Transistor (IGBT), and in this case comprises a gate instead of the base B, respectively.

One of the two diodes 81 is connected in parallel between the emitter E and the collector C of each of the two transistors 80. The bases B of both transistors 80 are connected to a common control unit 82. Both transistors 80 are operated by a common operating unit 82.

The present invention is not limited to the embodiments described herein and the aspects emphasized therein. Rather, within the scope of protection specified by the claims, a plurality of variants are possible, which are within the scope of processing of the person skilled in the art.

Claims

1. Multiphase inverter (10) for operating a multiphase consumer (50), comprising:

a plurality of input terminals (25, 26, 27, 28) for connecting at least one first battery pack (21) and at least one second battery pack (22); and a plurality of phase outputs (51, 52, 53) for connecting consumers (50), wherein

A bridge circuit (31, 32, 33) having controllable switches (S1, S2, S3, S4, S5; S6, S7, S8, S9, S10; S11, S12, S13, S14, S15) is associated with each phase output (51, 52, 53), by means of which bridge circuit the phase outputs (51, 52, 53) can be connected to different input terminals (25, 26, 27, 28),

it is characterized in that the preparation method is characterized in that,

each bridge circuit (31, 32, 33) has:

an input switch (S1; S6; S11) which is connected to the first input connection (25) and to the phase output (51, 52, 53);

a plurality of node switches (S2, S3, S5; S7, S8, S10; S12, S13, S15) which are connected to the remaining input terminals (26, 27, 28) and to the nodes (41, 42, 43); and

an output switch (S4; S9; S14) connected to the node (41, 42, 43) and to the phase output (51, 52, 53).

2. The inverter (10) of claim 1,

three phase outputs (51, 52, 53) are provided for connecting a three-phase consumer (50).

3. The inverter (10) of claim 1 or 2,

the switches (S1, S2, S3, S4, S5; S6, S7, S8, S9, S10; S11, S12, S13, S14, S15) comprise at least a transistor (80), a diode (81) and a manipulation unit (82).

4. The inverter (10) of claim 1 or 2,

a first input connection terminal (25) and a second input connection terminal (26) are provided for connecting the first battery pack (21), and a third input connection terminal (27) and a fourth input connection terminal (28) are provided for connecting the second battery pack (22).

5. The inverter (10) of claim 4,

when switches (S1, S2, S3, S4, S5; S6, S7, S8, S9, S10; S11, S12, S13, S14, S15) are open, the first input connection terminal (25) and the second input connection terminal (26) are galvanically isolated from the third input connection terminal (27) and from the fourth input connection terminal (28).

6. The inverter (10) of claim 5,

each bridge circuit (31, 32, 33) has a primary node switch (S2; S7; S12) which is connected to the second input connection (26) and to the node (41, 42, 43).

7. The inverter (10) of claim 6,

the primary node switches (S2; S7; S12) are implemented as anti-parallel switches and each comprise two transistors (80), two diodes (81) and a control unit (82).

8. The inverter (10) of claim 4,

9. The inverter (10) of claim 8,

10. The inverter (10) of claim 1 or 2,

when switches (S1, S2, S3, S4, S5; S6, S7, S8, S9, S10; S11, S12, S13, S14, S15) are open, the first battery pack (21) is galvanically isolated from the second battery pack (22).

11. Use of an inverter (10) according to one of the preceding claims in an Electric Vehicle (EV), in a Hybrid Electric Vehicle (HEV), in a plug-in hybrid electric vehicle (PHEV) or in a photovoltaic installation.