EP3143684A1

EP3143684A1 - Converter comprising redundant switch-fuse combinations and method for selective triggering of the fuse in the event of switch failure

Info

Publication number: EP3143684A1
Application number: EP15725288.3A
Authority: EP
Inventors: Rainer LEHNERT; Markus Pfeifer
Original assignee: Siemens AG
Current assignee: Siemens AG
Priority date: 2014-07-09
Filing date: 2015-05-20
Publication date: 2017-03-22
Also published as: BR112017000204A2; WO2016005092A1; CA2954477A1; CN106797173A; US20170197509A1; DE102015206627A1

Abstract

The invention relates to a converter (1) comprising an intermediate circuit (3) for providing a DC voltage (10) between a positive conductor (11) and a negative conductor (12), a phase conductor (8, 9) for receiving and/or output of an AC voltage, and a half-bridge circuit (17) comprising a first switch arrangement (18) for connecting the positive conductor (11) to the phase conductor (8, 9) and a second switch arrangement (19) for connecting the negative conductor (12) to the phase conductor (8, 9). In case of a defect of a semiconductor switch (20, 21) of the converter (1), the converter (1) is to be able to protect itself and continue to operate. For this purpose, the first switch arrangement (18) and the second switch arrangement (19) respectively have a parallel connection made of multiple switching branches (Z) and, in each switching branch (Z), one of the semiconductor switches (20, 21) is provided with an intrinsic safety fuse (22) switched in series to the contact gap of the semiconductor switch (20, 21).

Description

description

The invention relates to an inverter, to a vehicle having the converter according to the invention, and to a method for operating the converter. The converter has a DC intermediate circuit whose positive line and negative line are connected via a half-bridge circuit with an AC voltage phase conductor. The half-bridge circuit is formed on the basis of semiconductor switches.

Such semiconductor switches may require the interruption of the operation of the inverter in case of a defect, so that the half-bridge circuit can be repaired. However, this is not always possible, for example during a flight ei ^¬ nes aircraft whose propeller is driven by an electric motor, which in turn is powered by the inverter. But semiconductor switch for such an electrically powered aircraft are exposed to a much more intense cosmic radiation. This increases the likelihood of failure or destruction of one or more of the semiconductor switches. In such a defect, it is unpredictable, which state a defective semiconductor switch occupies. In the case of an IGBT (insulated gate bipolar transistor), a MOSFET (metal-oxide semiconductor field effect transistor) or a diode as a respective semiconductor switch, it can happen that the semiconductor switch becomes conductive or alloyed in the event of a fault and another fault ^¬ case remains non-conductive or permanently open. The defective semiconductor switch can then no longer be converted by a control signal in another state. In order to adequately respond to the defective state, very rapid detection and activation is required in order, if appropriate, to use the semiconductor solid-state switch, which is permanently electrically conductive, with the help of further switches from the system. separate. This type of protective device increases the number of components and increases the required installation space. Particularly in the case of contactors or relays for disconnecting semiconductor switches, the additional expense is undesirably high. However, if no protective measures are available, uncontrollable equalizing currents occur in the event of a fault. Said Koen ^¬ nen due to a defective semiconductor switch which is traversed by a short-circuit current, more semiconductors and for the drive to be total destroyed.

The invention has for its object to react quickly and robustly to a defect in one of the semiconductor switch of the inverter during operation of an inverter. The problem is solved by the subject matters of the independent Pa ^¬ tentansprüche. Advantageous developments of the inven ^¬ tion are given by the features of the dependent claims. The invention comprises a converter with a DC link for providing a DC voltage between a positive line and a negative line. The converter further comprises at least one phase conductor for receiving and / or outputting an alternating voltage. The invention is described below with reference to a single phase conductor which

Explanations also apply to other phase conductors. The phase conductor is connected via a half-bridge circuit to the plus line and the minus line. The Halbbrü ^¬ bridge circuit has a first switch means for connects the positive conductor to the phase conductor and a second

Switch arrangement for connecting the negative lead to the phase conductor. These switch arrangements are also referred to as high-side and low-side. In a known manner, a received alternating voltage are rectified or generated an alternating ^¬ voltage from the DC voltage of the intermediate circuit in the phase and output by alternate switching of the first switch arrangement and the second switch arrangement. To be able to nevertheless ensure continue to operate the inverter at a defective semiconductor switch in the half-bridge circuit, the invention provides that the first shawl ^¬ teranordnung and the second switching device has in each case a parallel circuit of a plurality of switching branches, wherein each branch circuit is a semiconductor switch with its own, in Row to the switching path of the semiconductor switch ge ^¬ switched fuse is provided. In the event that the inverter has a plurality of phase conductors, correspondingly each phase conductor is connected via a half-bridge circuit of the type described to the plus line and the minus line.

The invention has the advantage that, when a defective semiconductor switch when it is shorted, that is permanently and / or uncontrollably is electrically conductive, it is switched without effect through the fuse of the defective semiconductor switch by the melt Siche ^¬ tion blowing when a short-circuit current flows over the defective semiconductor switch. The converter can then continue to be operated with the other semiconductor switches from the at least one parallel switching branch. To trigger the fuse, not even detecting the defective semiconductor switch is necessary.

In the converter according to the invention, each semiconductor switch can be formed, for example, on the basis of an IGBT or egg ^¬ nes MOSFET or a diode. In the case of the abovementioned semiconductor switches, the switching path is the drain-source path or the collector-emitter path.

The converter according to the invention is in particular a 2-level converter. The invention also includes developments, the characteristics of which provide additional advantages. According to a development, a control device of the converter is designed to control the control inputs of the semiconductor switches, that is, the respective gate or the base, at the same time in each of the switch arrangements.

This has the advantage that the operation of the converter is continuously continued on the basis of the remaining semiconductor switches with a defect ei ^¬ nes the semiconductor switch. As already stated, can be rectified by the half-bridge circuit, an AC voltage or the DC voltage of the DC ^link in an AC voltage who ^¬ the. For this purpose, the first and the second switch arrangement must be alternately switched in each case. According to a development, this ensures that the first switch ^arrangement and the second switch arrangement are operated at different time intervals in an electrically conductive state. Is here in a time interval of a ^half-¬ conductor switch is damaged, so that it has shorted, then the next time interval in which the other scarf ^¬ teranordnung is operated, causing a short circuit between the positive line and the negative line through which the fuse of the defective semiconductor switch is released ^¬ . At the next time interval, in which again the first switch arrangement is turned on, it can then continue to function without the defective semiconductor switch.

According to a further development, it is ensured that the

Fuse of the defective semiconductor switch is destroyed by the short circuit and not the fuses of those semiconductor switch of the other switch assembly over which the short-circuit current (divided into partial streams) also flows. In this development, each fuse is designed to trigger only at a tripping current with a current equivalent to the short-circuit current between the positive and negative line, if this short-circuit current exclusively on the Fuse flows. This ensures that the fuse of the defective semiconductor ^switch triggers ^¬ . Since the short-circuit current in the other switch arrangement is divided among a plurality of semiconductor switches, their fuses do not trigger in this design of the fuses.

The inventive, self-locking inverter is particularly advantageous to use in vehicles, as they may not break their journey under certain circumstances in case of a defect of a semiconductor switch.

Accordingly, the invention also includes a vehicle with an electric drive motor for driving the vehicle for a drive, wherein the drive motor is coupled via an inverter with an electric generator. In this case, the converter represents an embodiment of the converter according to the invention. In the case of the vehicle according to the invention, there is the advantage that it does not have to interrupt its travel immediately in the event of a defect of a semiconductor switch.

According to a further development of the vehicle is formed as a plane from ^¬, particularly as a fixed wing aircraft. The drive ^¬ motor drives in this case the propeller of the aircraft or (in the case of a rotary wing aircraft) a rotor of the aircraft. Another development provides that the vehicle is designed as a power ^¬ venture, for example, as a passenger car or truck. During the running of the invention ^shown SEN motor vehicle, the drive motor can continue to operate for the wheels of the vehicle here as well, even if there is a defect in a semiconductor switch.

A further development provides that the drive motor, the converter and the generator are interconnected free of contactors. As a result, the vehicle is particularly compact and lightweight. A reduction of the installation space and the weight results according to a development also by the drive motor and the generator each having only a single multi-phase winding system. In other words, no redundant three-phase windings are provided, as are necessary, for example, when two inverters are operated in parallel to provide redundancy.

Finally, the invention also includes a method for operating an embodiment of the converter according to the invention. By means of the method, a defective semiconductor switch ^¬ which persists permanently in an electrically conductive state, made ineffective. In operation of the converter, while the inverter is receiving a first AC voltage of a predetermined frequency, for example from a generator, and generating a second AC voltage having an adjustable frequency, for example, to output to a drive motor, the following is done. At the switch arrangement of the half-bridge circuit, in which the defective semiconductor switch is arranged, a STEU ^¬ ersignal for opening all semiconductor switches is generated. The defective semiconductor switch will not respond to the signal. All other functional semiconductor switches respond to the control signal by changing to a non-conductive state. At the other switch arrangement of the half-bridge circuit, a signal for closing all semiconductor switches is generated. Thereby, the positive line and the negative line of the intermediate circuit on the defective semiconductor terschalter be the one hand and at least two other semiconducting ^¬ terschalter the other switch arrangement on the other hand short-circuited. As a result, a short-circuit current flows between the positive line and the negative line, the short-circuit current flows completely through the defective semiconductor switch. In the other switch arrangement, the short-circuit current is split between the at least two further semiconductor switches. As a result, the fuse of the defective semiconductor switch is triggered. The procedure is automatically romantic performed during operation of the converter without here ^¬ ^¬ necessary laundri re at a detection of the defective semiconductor switch. The invention also includes developments of the method according to the invention having features as they have already been described in connection with the developments of the inverter according to the invention. For this reason, the corresponding developments of the method according to the invention are not described here again.

In the following an embodiment of the invention is described. 1 shows a schematic representation of an embodiment of the converter according to the invention,

2 shows a schematic representation of part of the Um ^¬ judge of FIG 1, while an embodiment of the method according to the invention is carried out, and

3 shows a schematic representation of an embodiment of the vehicle according to the invention.

The exemplary embodiment explained below is a preferred embodiment of the invention. In the embodiment described components of the embodiment respectively represent individual, regardless to be viewed from each other characteristics of the invention, further forming the OF INVENTION ^¬ dung each independently of each other and thus individually or are to be considered part of the invention other than the combination shown. Furthermore, the described embodiment is also by further of the already described features of the invention

supplemented. In the figures, functionally identical elements are each provided with the same reference numerals.

1 shows a converter 1 which has a rectifier 2, an intermediate circuit 3, an inverter 4 and a control device 5. Via the converter 1, a voltage source 6 (for example an electric generator) and an electrical consumer 7 (for example an electric motor) can be coupled together. The voltage source 6 can be connected to the rectifier 2 via phase lines 8. The consumer 7 may be connected via phase lines 9 to the inverter 4. AC voltages of different phases can be transmitted in each case via the phase lines 8, 9.

From the AC voltages of the phase lines 8, a DC voltage 10 can be generated by the rectifier 2, which is fed into the DC link 3. The intermediate ^¬ circle 3 may have a positive line 11 and a minus line 12, between which the DC voltage 10 is applied. The positive line 11 and the negative line 13 may be coupled via a battery 13 and an intermediate circuit capacitor 14, through which a ^{DC link} capacitor C ^{bereitge ¬} is. The plus line 11 and the minus line 12 respectively couple the rectifier 2 and the inverter 4.

The plus line 11, the minus line 12 and the phase lines 8, 9 may each be provided, for example, by a wire or a bus bar. During operation of the converter 1, the converter 1 converts the alternating voltages in the phase conductors 8 into alternating voltages which are supplied to the load 7 via the phase conductors 9. The inverter 1 is hereby secured as a redundant inverter against a defect. Nevertheless, the voltage source 6 requires as a generator only a single generator winding system 15 in the stator. The consumer 7 needs as an electrical machine ne only a single motor winding system 16 in the stator. In the event of a defect, it is not necessary to switch the power flow using contactors. The redundancy may also be provided with a single link capacitor 14 and a single battery 13.

The rectifier 2 and the inverter 4 each have half bridges 17, each of which interconnects or connects the plus line 12 and the minus line 13 to another one of the phase lines 9. For clarity, only three of the half-bridges are provided with a reference numeral.

Each half bridge 17 can have two switch arrangements 18, 19. The switch assembly 18 is also known as a high-side

Circuit, the switch assembly 19 as a low-side circuit, referred to. At each half-bridge 17, the switch ^arrangement 18 connects the positive line 12 to the respective phase line 9. The switch arrangement 19 connects the negative line 13 to the same phase line 9. Alternating ^{switching of} the switch arrangements 18, 19 in the rectifier 2 becomes known per se Way from an AC voltage of the phase conductor 8, the DC voltage 10 is generated. By alternately switching the switch assemblies 18, 19 in the inverter 4 is in a conventional manner from the

DC voltage 10 in each case a phase conductor 9 impressed or generated an AC voltage.

For controlling the switch arrangements 18, 19 of the half bridges 17, control terminals G of the switch arrangements 18, 29 can be coupled to the control device 5. The control device 5 can be completely or partially integrated in the switch assemblies 18, 19. It may be partially or wholly provided as a separate control unit.

The rectifier 2 and the inverter 4 may have the same circuit topology, ie they may be of identical construction. To provide the said redundancy have in the

Rectifier 2 and the inverter 4, the switch assemblies 18, 19 each have a plurality of semiconductor switches 20, 21 on. Each semiconductor switch 20, 21 is a separate Schmelzsiche ^¬ tion 22 connected in series. In each switch assembly 18, 19 so a parallel circuit of several series scarf ^¬ lines or switching branches Z is provided, each switching branch Z is formed on the basis of a semiconductor switch 20, 21 and a fuse 22. Each semiconductor switch 20, 21 may be configured, for example, as an IGBT or MOSFET.

For the further explanation of the exemplary embodiment, reference is made to FIG. 2 and it is assumed that one of the semiconductor switches 20 of the inverter 4 is defective. The defective semiconductor switch 20 will hereinafter be referred to as a defective semiconductor switch 23. Due to the defect, the defective semiconductor switch 23 is continuously electrically conductive, that is, in the illustrated example, the positive lead 12 is permanently electrically connected or short-circuited to a phase conductor 9.

In the inverter 1, a method by which the associated with the defective semiconductor scarf ^¬ ter 23 fuse is triggered or melted 24 so that is caused by the fuse 24, an electrical disconnection or electrical insulation is given by its topology. As a result, the positive line 12 is then electrically separated from the phase conductor 9 in the example, although the defective semiconductor switch 23 is permanently electrically conductive. A detection of the defective semiconductor 23 is eliminated.

In the method of the non-defective semiconductor switches 21, so the semiconductor switch in that the switch assembly 19 in which not the defective semiconductor switch 23 is, the defective semiconductor scarf ^¬ ter 23 via its fuse 24 from the intermediate circuit 3 is disconnected by switching. By closing the semiconductor switch 21, that is by switching the semiconductor switch 21 in the electrically conductive state (ON), the positive line 12 with the Minuslei ^¬ tion 13 via the defective semiconductor switch 23 in the permanently conductive state (DEF) on the one hand and the semiconductor switch 21 on the other electrically shorted. It flows through a short-circuit current I.

The remaining semiconductor switches 20 of the switch assembly 18, in which the defective semiconductor switch 23 is located, are switched to an electrically blocking state (OFF), that is to say in an opened state. As a result, the short-circuit current I is completely routed via the fuse 24 and the defective semiconductor switch 23. In the switch arrangement 19, the short-circuit current I divides as partial current 1/2 onto the semiconductor switches 21. This prevents their fuses 22 melt or trigger. The fuses 22 of each semiconductor switch 20, 21 is thus not designed for the rated current, but for the short-circuit current I. So that the short-circuit current I divides the two semiconductor switches 21 as a partial current 1/2, the semiconductor switches 21 are driven simultaneously. For this purpose, the semiconductor switches 21 and also the semicon ^¬ terschalter 20 via their control terminals, that is their gate or their base, connected via a common control line 25. In FIG. 1 it is indicated by means of omission points at the control connections G and by corresponding outlet points on the control device 5, how each of the control lines 25 can be controlled by the control device 5.

In the case of a defective semiconductor switch 23, the operation of the converter 1 continues normally. The broken one

(all-alloyed) semiconductor switch 23 connects the positive point of the intermediate circuit voltage 10 to a phase line 9. Will now be the semiconductor switches 21, the negative point connect the negative line 12 with the same phase line 9, driven, so there is a saturated short circuit of the intermediate circuit voltage 10. The short-circuit current I is divided across the two switched semiconductor switches 21 and their

Fuses 22 on. However, the complete short-circuit current I flows through the defective (all-alloyed) semiconductor switch 23 and its fuse 24, which thus triggers. The defective semiconductor switch 23 is thus taken out of service, that is, its switching branch Z is in an electrically non-conductive, open state. The parallel to the defective semiconductor switch 23 switched semiconductor switch 20 (in the example, only another semiconductor switch 20 is connected in parallel) continue to switch the proportion of the intermediate circuit voltage.

Applications are in addition to an electrically powered aircraft (ePlane) and electrically driven Kraftfahrzeu ^¬ gene (eCar) and a drive converter with increased redundancy requirement and / or a SIL level (SIL - safety integrity level according to international standard IEC 61508 / IEC 61511 ).

FIG 3 illustrates this as the inverter 1 for ^¬ adhesive may be provided in an aircraft 26th Instead of the aircraft 26, the inverter may also be provided in another vehicle, eg a motor vehicle.

3 shows a fixed wing aircraft 26, in which a Pro ^¬ peller 27 can be driven by the consumer 7. The propeller 27 is rotated by a shaft 28 through the consumer 7. In the example, the consumer 7 is an electric drive motor, that is to say an electric machine which is operated during engine operation. The energy for the on ^¬ drove the propeller 27 can be obtained by an internal combustion engine 29, which is, for example, may be a gasoline engine or a diesel engine. The internal combustion engine 29 may be 6 to ^¬ drive the voltage source via a shaft 30, which for this purpose designed as an electric generator is. As an electric generator, an electric machine may be provided in the generator mode. In this case, a rotational speed of the shaft 30 is independent of a rotational speed of the shaft 28. For this purpose, the AC voltage generated by the voltage source 6 is converted in the described manner via the converter 1 into AC voltage, which via the AC voltage phase conductor 9 in the consumer 7 can be fed. In this case, a switching frequency of the switch arrangements 18, 19 is set by the control device 5 as a function of a desired rotational speed of the propeller 27. The target rotation ^¬ number can be set or predetermined in this case, for example, by a pilot by means of a (not shown) operating element. Overall, the example shows how the invention can provide a 2-level inverter with fuses.

Reference sign list

1 inverter

2 rectifiers

3 DC link

4 inverters

5 control device

6 voltage source

7 consumers

8, 9 phase line

10 DC voltage

11 plus line

12 negative lead

13 battery

14 DC link capacitor

15 generator winding system

16 motor winding system

17 half-bridges

18, 19 switch arrangement

20, 21 semiconductor switches

22 fuse

23 Defective semiconductor switch

24 fuse

25 control line

26 aircraft

27 propellers

28 wave

29 internal combustion engine

30 wave

G control connection

I short-circuit current

12 partial flow

Z switching branch

Claims

claims

1. Inverter (1) with

an intermediate circuit for providing a direct voltage between a positive line and a negative line

a phase line (8, 9) for receiving and / or outputting an alternating voltage,

- A half-bridge circuit (17) having a first switch arrangement (18) for connecting the positive line (11) with the

Phase line (8, 9) and a second switch arrangement (19) for connecting the negative line (12) to the phase line (8, 9),

characterized in that

the first switch arrangement (18) and the second switch arrangement (19) each have a parallel connection of a plurality of switching branches (Z) and in each switching branch (Z) a semiconductor switch (20, 21) with its own, in series with the switching path of the semiconductor switch (20, 21) switched fuse (22) is provided.

2. Inverter (1) according to claim 1, wherein a control device (5) is adapted to control at each switch arrangement (18, 19) each control inputs of the semiconductor switches (20, 21) at the same time.

3. converter (1) according to one of the preceding claims, wherein the control device (5) is adapted to Erzeu ^¬ conditions of the AC voltage from the DC voltage (10) or for generating the DC voltage (10) from the AC voltage, the first switch assembly (18 ) and the second ^{Schalteranord ¬} tion (19) to operate at different time intervals in an electrically conductive state.

4. Inverter (1) according to one of the preceding claims, wherein each semiconductor switch (20, 21) is formed by an IGBT or a MOSFET or a diode.

5. converter (1) according to any one of the preceding claims, wherein each fuse (22) is adapted to each trigger only at a tripping current with a current that a short-circuit current (I) between the positive line (11) and the negative line (12) corresponds, if this short-circuit current (I) only via the fuse

(22) flows.

6. Vehicle (26) with an electric drive motor (7) for driving the vehicle (26) for a drive, wherein the on ^¬ drive motor (7) via an inverter (1) according to one of the preceding claims with an electric generator (6). is coupled.

7. vehicle (26) according to claim 6, wherein the drive motor

(7), the inverter (1) and the generator (6) are interconnected free of contactors.

8. Vehicle (26) according to claim 6 or 7, wherein the drive motor (7) and the generator (6) each only a single

Multi-phase winding system (15, 16).

9. Vehicle (26) according to any one of claims 6 to 8, wherein the vehicle (26) as an aircraft (26), in particular fixed wing aircraft, or designed as a motor vehicle.

10. A method for operating an inverter (1) according to one of claims 1 to 5, to a defective semiconductor switch

(23), which remains permanently in an electrically conductive state (DEF), to render ineffective, wherein in the operation of the

Inverter (1), while receiving a first AC voltage with a predetermined frequency and generates a second AC voltage with adjustable frequency, at the switch assembly (18), in which the defective semiconductor switch (23) is arranged, a control signal for opening all semiconductor switches ^¬ ( 20) is generated, and at the other switch arrangement (19) of the same half-bridge circuit (17) generates a control signal for closing all the semiconductor scarf (21) and thereby the plus line (11) and the minus line (12) are short-circuited via the defective semiconductor switch (23) and at least two further of the semiconductor switches (21) of the other switch arrangement (19) and thereby the fuse (24) of the defective semiconductor switch (23) is triggered.