Electrical energy supply devices for three-phase and single-phase circuits, associated auxiliary energy conversion systems and electric vehicles

Abstract

To propose a supply device while limiting cost, weight, volume, and energy loss in use.SOLUTION: A supply device (20) is for supplying electric energy for a three-phase circuit and a single-phase circuit. The supply device has a rectifier (60) converting first AC voltage into second DC voltage, and having two input terminals (72) for the first voltage and two output terminals (74) for the second voltage, an inverter configured so as to convert the second voltage into three third three-phase voltage, and having an input terminal (92) for the second voltage and three output terminals (94) for the three third voltage, and a neutral terminal (66) connected to the output terminals of the inverter respectively through a capacitor (110).SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an electrical energy supply device for three-phase and single-phase circuits. [Background technology]

[0002] The invention likewise relates to an electric vehicle, in particular on railways, equipped with such a supply device.

[0003] The invention also relates to an electric vehicle, in particular on railways, equipped with such an energy conversion system.

[0004] The present invention relates to the field of transport, in particular to the field of rail transport, and in particular to the electricity supply of electric vehicles such as locomotives, rail cars, subways, trams and electric buses.

[0005] Electric vehicles, particularly on railroads, are typically provided with auxiliary three-phase electrical loads (such as air compressors, heating / ventilation / air conditioning (HVAC) systems, or electric traction system ventilation). In this application, the term "auxiliary electrical loads" specifically refers to auxiliary electrical loads other than the vehicle's traction motors. To supply such three-phase auxiliary loads, an inverter is typically used, which delivers electrical energy directly to the three-phase electrical loads to operate them.

[0006] Conventionally, inverters are connected to an AC voltage source using a converter such as a rectifier coupled to a filter capacitor to convert the AC voltage into a DC voltage for the inverter. In such cases, the supply device is formed by both the rectifier coupled to the filter capacitor and the inverter.

[0007] Furthermore, there is a need for a supply device that supplies an AC voltage having an average value that is less than the average value of the voltage delivered by the inverter to single-phase auxiliary loads such as heating for the driver's cab, single-phase outlets (e.g., 230V) available to passengers, kitchens, and washrooms, so that each single-phase auxiliary load between the neutral terminal and the inverter output terminals can be supplied with an intermediate voltage between the voltages of each of the phases, i.e., the intermediate voltage between the inverter output terminals. Summary of the Invention [Problem to be solved by the invention]

[0008] An existing solution to achieve this is to form a neutral terminal by connecting the capacitors of the output filter of the supply device in a wye configuration to each of the inverter's output terminals, and to connect the neutral terminal to the inverter's output terminals via a transformer in a staggered configuration. However, such a device requires transformer windings that have significant mass and involve considerable energy losses.

[0009] The object of the present invention is to propose such a supply device while limiting its cost, mass, volume and energy losses during use.

[0010] To that end, one object of the present invention is an electrical energy supply device for three-phase and single-phase circuits. [Means for solving the problem]

[0011] The supply device comprises a rectifier configured to convert a first AC voltage into a second DC voltage, the rectifier having two input terminals for the first voltage and a second output terminal for the second voltage, and two switching arms connected in parallel between the output terminals of the rectifier, each switching arm having two switching half-arms connected in series between the output terminals of the rectifier and connected to each other at midpoints, the midpoints respectively connected to input terminals of the rectifier, the switching half-arms respectively connected to the input terminals of the rectifier, the switching half-arms comprising at least one controllable switch and / or diode.

[0012] The supply device comprises a filter capacitor connected across the output terminals of the rectifier, an inverter configured to convert the second voltage into three third three-phase voltages, the inverter having two input terminals for the second voltages, the two input terminals respectively connected to the two output terminals of the rectifier, three output terminals for the three third voltages, and a neutral terminal connected to each of the output terminals of the inverter via a capacitor.

[0013] The neutral terminal is likewise connected via an inductor to one of the input terminals of the rectifier, the output terminal of the inverter being intended to be connected to a three-phase circuit, and the neutral terminal being intended to be connected to a single-phase circuit.

[0014] According to other advantageous aspects, the delivery device according to the invention comprises one or more of the following characteristics, in any technically possible combination: The rectifier has only two switching arms. - each switching half arm comprises at least one controllable switch, and the supply device comprises a rectifier control module configured to control the rectifier switches, the rectifier control module being configured to control the rectifier switches via a periodic control signal having a duty cycle of approximately 50%; - each switching half arm comprises at least one controllable switch, and the supply device comprises a rectifier control module configured to control the rectifier switches, the rectifier control module being configured to control the rectifier switches via periodic control signals having a frequency at least 20 times greater than the frequency of the third voltage; each switching half arm comprises at least one diode, and the frequency of the first AC voltage is at least 20 times greater than the frequency of the third voltage; the inverter further comprises three switching arms connected in parallel between the input terminals of the inverter, each switching arm comprising two switching half-arms connected in series between the input terminals of the inverter and connected to each other at midpoints, each midpoint being connected to a respective output terminal of the inverter via a filter inductor, each switching half-arm comprising at least one controllable switch and a control module configured to control the switches of the inverter. Each switch comprises a controllable switching semiconductor element and a diode connected in anti-parallel with the switching semiconductor element.

[0015] A further object of the invention is an energy conversion system for electric vehicles, in particular on railways, comprising at least one three-phase electric load, at least one single-phase load, an electric energy supply system for at least one three-phase and one single-phase load, and an AC voltage providing system, the supply device being as described above, the AC voltage providing system being connected to the input terminals of the rectifier of the supply device, each three-phase electric load being connected to the output terminals of the inverter of the supply device, and each single-phase load being connected between the neutral terminal of the supply device and one of the output terminals of the inverter of the supply device.

[0016] According to another advantageous aspect, the energy conversion system according to the invention comprises the following features: The AC voltage providing system comprises an AC voltage generating module and a transformer.

[0017] A further object of the invention is an electric vehicle, in particular on railways, comprising an energy conversion system as described above.

[0018] These features and advantages of the invention will become apparent upon reading the following description, given by way of non-limiting example, with reference to the accompanying drawings, in which: [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a circuit diagram showing an electric transport vehicle, such as a rail vehicle, comprising an electrical conversion system, the electrical conversion system comprising, inter alia, an AC voltage providing system and a supply device according to the invention; [Figure 2] 2 is a more detailed circuit diagram showing the supply device of FIG. 1 and an AC voltage providing system in a specific case. DETAILED DESCRIPTION OF THE INVENTION

[0020] FIG. 1 shows an electric vehicle 10 , in particular on a railway, such as a train or tram, which is equipped with an energy conversion system 15 .

[0021] The energy conversion system 15 comprises an AC voltage providing system 18 which is connected to a supply device 20 which supplies electrical energy to a three-phase circuit 24 and a single-phase circuit 26 of the energy conversion system 15 .

[0022] FIG. 2 shows one type of AC voltage providing system and supply device 20 in more detail.

[0023] In the embodiment of FIG. 2, the AC voltage providing system 18 comprises an AC voltage generating module 30 connected to a transformer 32 .

[0024] According to the example of FIG. 2, the generation module 30 comprises a converter 40, such as a single-phase inverter, for converting a DC voltage into an AC voltage.

[0025] Converter 40 is a DC overhead line voltage step-down or step-up converter configured to convert the DC voltage delivered by the third rail or by the surface supply of DC power into an AC voltage that is delivered to transformer 32 .

[0026] According to the illustrated example, the converter 40 comprises two first input terminals 42 connected to a DC voltage source (not shown), two first output terminals 44 connected to the transformer 32, and two first switching arms 46 connected in parallel between the first input terminals 42. The converter 40 further comprises a capacitor 47 connected in parallel with the two first switching arms 46 to the two first input terminals 42.

[0027] Each first switching arm 46 has two first switching half arms 48 connected in series between the first input terminals 42 and connected to each other at first intermediate points 50, each of which is connected to a first output terminal 44.

[0028] Each first switching half arm 48 includes one or more first switches 52, which are connected in series if warranted. In the example of Figure 2, each first switching half arm 48 includes a single first switch 52.

[0029] In a variant not shown, each first switching half arm 48 includes N switching half branches connected in parallel, where N is an integer greater than or equal to 2, and each switching half branch includes at least one first switch 52. Thus, each first switching half arm 48 includes at least N switches 52.

[0030] The converter 40 further comprises a first control module (not shown), which is configured to control the first switch 52 .

[0031] Each first switch 52 comprises, for example, a controllable switching semiconductor element 54 and a diode 56 connected in anti-parallel with the controllable switching semiconductor element 54 .

[0032] Furthermore, depending on the controllable switching semiconductor component 54, the diode 56 may form an inherent part of the controllable switching semiconductor component 54 or may be absent in the case of a bidirectional controllable switching semiconductor component 54.

[0033] As is known per se, each controllable switching semiconductor element 54 comprises two conducting electrodes carrying a power supply current and one or two control electrodes, and each controllable switching semiconductor element 54 is controllable via the control electrodes of the semiconductor element between an "on" state, in which current flows between the conducting electrodes, and an "off" state, in which no current flows between the conducting electrodes. For this purpose, a diode 56 is connected between the conducting electrodes, thereby allowing current to flow in the reverse direction.

[0034] The first control module is configured to control the first switch 52 via a periodic first control signal, such as a square wave signal.

[0035] The duty cycle of a square wave signal is the ratio of the duration that the signal is in a high state to the duration that the signal is in a low state.

[0036] For example, each of the first control signals has a duty cycle of approximately 50% or less.

[0037] The transformer 32 is known per se and comprises one or more primary windings connected to the first output terminal 44 and a secondary winding connected to the supply device 20. The transformer is configured to transform the AC voltage intensity emitted by the generating module 30 based on a turns ratio equal to the ratio between the number of turns of the secondary winding and the number of turns of the primary winding.

[0038] In one variant not shown, the AC voltage supply system 18 comprises a pantograph in contact with the overhead lines that provide the AC overhead voltage and thereby connect to the power grid and to a transformer.

[0039] The pantograph can deliver AC voltage emitted by the power grid to a primary winding of a transformer, the transformer being configured to reduce the magnitude of the AC voltage based on a turns ratio and to deliver the reduced magnitude AC voltage through a secondary winding.

[0040] The supply device 20 is configured to supply a three-phase voltage to a three-phase circuit 24 and an AC voltage to a single-phase circuit 26 from the AC voltage provided by the AC voltage providing system 18 .

[0041] The supply device 20 comprises a rectifier 60 , a filter capacitor 62 and an inverter 64 connected to the rectifier 60 , the inverter being connected to the three-phase circuit 24 .

[0042] The supply device 20 further comprises a neutral terminal 66 connected to the single-phase circuit 26 .

[0043] The rectifier 60 is configured to convert the AC voltage provided by the AC voltage providing system 18 into a DC voltage.

[0044] The rectifier 60 comprises two second input terminals 72 connected to the AC voltage providing system 18, and subsequently to the second winding of the transformer 32, a second output terminal 74 configured to deliver a DC voltage, and two second switching arms 76 connected in parallel between the second output terminals 74.

[0045] In particular, the rectifier 60 includes only two second switching arms 76 .

[0046] Each second switching arm 76 has two second switching half arms 78 connected in series between the second output terminals and connected to each other at second intermediate points 80, each of which is connected to a second input terminal 72.

[0047] In one variant not shown, one of the intermediate points 80 is connected to the corresponding second input terminal 72 via an inductor.

[0048] Each second switching half arm 78 includes at least one second switch 82. For example, the second switching half arms 78 are similar to the first switching half arms 48.

[0049] The rectifier 60 further comprises a second control module (not shown), which is configured to control the second switch. In one variant, the second control module is integrated with the first control module.

[0050] For example, the second switches 82 are similar to the first switches 52 , and each second switch comprises a controllable switching semiconductor element 54 and a diode 56 connected in anti-parallel to the controllable switching semiconductor element 54 .

[0051] The second control module is configured to control the second switch 82 via a periodic second control signal, such as a square wave signal.

[0052] Preferably, each of the second control signals has a duty cycle of approximately 50% or less.

[0053] In one variant not shown, each second switching half arm 78 comprises at least one diode that is naturally controlled based on the alternating voltage across the second input terminals 72 and the minimum current required to naturally switch the diode. In such a case, the rectifier control module is not present and the alternating operation of the transformer 32 ensures that the diode switches with a 50% duty cycle.

[0054] The filter capacitor 62 is connected across the second output terminal 74 .

[0055] The inverter 64 is a three-phase inverter known per se, which is configured to convert the DC voltage delivered across the second output terminals 74 into three third three-phase voltages.

[0056] The three three-phase voltages are three sinusoidal AC voltages with the same frequency and amplitude, and each of the three phase voltages is shifted in phase with each other by 2π / 3 radians.

[0057] The inverter 64 has two third input terminals 92 respectively connected to the two second output terminals 74 , and three third output terminals 94 connected to the three-phase circuit 24 .

[0058] Typically, the inverter 64 further includes three third switching arms 96 connected in parallel between the third input terminals 92 .

[0059] Each third switching arm 96 has two third switching half arms 98 connected in series between the third input terminals 92 and connected to each other at third intermediate points 100, each of which is connected to a third output terminal 94.

[0060] Each third switching half arm includes at least one third switch 102. For example, the third switching half arm 98 may be similar to the first switching half arm 48 and / or the second switching half arm 78.

[0061] The inverter 64 further comprises a third control module (not shown), which is configured to control the third switch 102. In one variant, the third control module is integrated with the first control module and / or the second control module.

[0062] For example, the third switches 102 are similar to the first switches 52 , and each third switch comprises a controllable switching semiconductor element 54 and a diode 56 connected in anti-parallel to the controllable switching semiconductor element 54 .

[0063] Furthermore, each of the third intermediate points 100 is connected to the third output terminal 94 via a sinusoidal three-phase filter inductor 106 .

[0064] The third control module is configured to control the third switch 102 via a periodic third control signal, such as a square wave signal.

[0065] For example, each of the third control signals has a duty cycle resulting from a sinusoidal modulation signal and a sawtooth carrier signal, the period of which is much greater than the period of the sinusoidal modulation signal.

[0066] For example, the three-phase voltage delivered by the third output terminals 94 has a frequency of 50 Hz or 60 Hz.

[0067] Additionally, each of the second control signals has a frequency at least 20 times greater than the frequency of the three-phase voltage delivered by the third output terminals 94. For example, therefore, each of the second control signals has a frequency greater than 1 kHz.

[0068] When each second switching half arm 78 includes at least one diode, the frequency of the first AC voltage is at least 20 times greater than the frequency of the third voltage.

[0069] The neutral terminal 66 is connected to each of the third output terminals 94 via capacitors 110, which belong to a sinusoidal three-phase filter and are connected in a wye configuration, so that the neutral terminal 66 is connected to the center of the wye configuration.

[0070] Additionally, the neutral terminal 66 is connected to one of the second input terminals 72 of the rectifier 60 via an inductor 120 .

[0071] For example, the neutral terminal 66 is connected to one of the second input terminals 72 by one of the second intermediate terminals 80 .

[0072] Therefore, the voltage magnitude between the neutral terminal 66 and one of the third output terminals 94 is lower than the voltage magnitude between the two third output terminals 94 .

[0073] The mean square of the AC voltage is called the effective voltage.

[0074] For example, the effective voltage between the neutral terminal 66 and one of the output terminals 94, i.e., the voltage between the two third output terminals 94 divided by √3, is 230V, and the effective voltage between the two third output terminals 94 is 400V.

[0075] According to the example in FIG. 1, a three-phase circuit 24, such as an air compressor, HVAC system, or traction system ventilation, is connected to each of the third output terminals 94.

[0076] According to the example in FIG. 1, the single-phase circuit 26 includes a single-phase load 140 connected between the neutral terminal 66 and one of the third output terminals 94 .

[0077] For example, load 140 may be the driver's cab heating, a single phase output (eg, 230V) available to passengers, a kitchen, and a washroom.

[0078] In one variant not shown, the three-phase circuit 24 and the single-phase circuit 26 are combined into a single circuit connected to the third output terminal 94 and the neutral terminal 66 .

[0079] In such a case, the supply device 20 is able to supply electrical energy to a three-phase circuit at a three-phase voltage and to a single-phase circuit at an AC voltage whose effective value is lower than that of the three-phase voltage.

[0080] The supply device 20 allows AC voltage to be delivered to the neutral terminal 66 by limiting the weight and volume of the device as well as the cost of materials used and energy losses during use.

[0081] This is because the supply device 20 uses the already existing second switching arm 76 in the rectifier 60, thereby forming a midpoint corresponding to the second midpoint 80. Therefore, no further switching arms need to be added to have such a midpoint, which in particular allows reducing the number of controllable switching semiconductor components used and thus the material used to control such switching arms. [Explanation of symbols]

[0082] 10 electric vehicle, 15 energy conversion system, 18 AC voltage supply system, 20 electrical energy supply device, 24 three-phase circuit, 26 single-phase circuit, 30 AC voltage generation module, 32 transformer, 52 first switch, controllable switch, 54 bidirectional controllable switching semiconductor component, 56 diode, 60 rectifier, 62 filter capacitor, 64 inverter, 66 neutral terminal, 72 second input terminal, 74 second output terminal, 76 second switching arm, 78 second switching half arm, 80 second intermediate terminal, second intermediate point, 82 second switch, controllable switch, 92 third input terminal, 94 third output terminal, 96 third switching arm, 98 third switching half arm, 100 third intermediate point, 102 third switch, controllable switch, 106 sinusoidal three-phase filter inductor, 110 capacitor, 120 inductor, 130 three-phase electrical load, 140 single-phase electrical load

Claims

1. An electrical energy supply device (20) for a three-phase circuit (24) and a single-phase circuit (26), comprising: a rectifier (60) configured to convert a first AC voltage into a second DC voltage, + two input terminals (72) for said first AC voltage and two output terminals (74) for said second DC voltage, a rectifier comprising: an inverter (64) configured to convert the second DC voltage into three third three-phase voltages, the inverter comprising two input terminals (92) for the second DC voltage, the two input terminals being respectively connected to the two output terminals (74) of the rectifier (60), and three output terminals (94) for the three third three-phase voltages; a neutral terminal (66) connected to each of said output terminals (94) of said inverter (64) via a capacitor (110); Equipped with the output terminal (94) of the inverter (64) is intended to be connected to the three-phase circuit (24) and the neutral terminal (66) is intended to be connected to the single-phase circuit (26); the rectifier (60) further comprises only two switching arms (76); The two switching arms (76) are connected in parallel between the output terminals (74) of the rectifier (60), Each of the switching arms (76) comprises two switching half arms (78) connected in series between the output terminals (74) of the rectifier (60) and connected to each other at a midpoint (80); The intermediate points (80) are respectively connected to the input terminals (72) of the rectifier (60); each of said switching half arms (78) includes at least one first controllable switch (82); the electrical energy supply device comprising a control module of the rectifier (60) configured to control the first controllable switch (82) of the rectifier (60); the control module of the rectifier (60) is configured to control the first controllable switch (82) of the rectifier (60) via a periodic control signal having a duty cycle of approximately 50% and at least 20 times greater than the frequency of the third three-phase voltage; The electrical energy supply device is characterized in that the neutral terminal (66) is further connected to one of the input terminals (72) of the rectifier (60) via an inductor (120).

2. 2. The electrical energy supply device of claim 1, further comprising a filter capacitor (62) connected across the output terminals (74) of the rectifier (60).

3. The inverter (64) three switching arms (96) connected in parallel between the input terminals (92) of the inverter (64), each of the switching arms (96) comprising two switching half arms (98) connected in series between the input terminals (92) of the inverter (64) and connected to each other at intermediate points (100), each intermediate point (100) being respectively connected to the output terminals (94) of the inverter (64) via a filter inductor (106), each of the switching half arms (98) comprising at least one second controllable switch (102); a control module of said inverter (64) configured to control said second controllable switch (102) of said inverter; 3. The electrical energy supply device according to claim 1, further comprising:

4. 3. The electrical energy supply device according to claim 1, wherein each of the first controllable switches (82) comprises a controllable switching semiconductor element (54) and a diode (56) connected in anti-parallel with the controllable switching semiconductor element.

5. An electrical energy supply device as described in Claim 3, characterized in that each of the second controllable switches (102) comprises a controllable switching semiconductor element (54) and a diode (56) connected in anti-parallel to the controllable switching semiconductor element.

6. An energy conversion system (15) for an electric vehicle (10), comprising at least one three-phase electrical load (130), at least one single-phase electrical load (140), an electrical energy supply device (20) for at least one of the three-phase electrical load and the single-phase electrical load (140), and an AC voltage providing system (18); The electrical energy supply device (20) is an electrical energy supply device according to any one of claims 1 to 5, an inverter (64) for inverters (64) of the electrical energy supply device (20); a power supply system (18) for supplying three-phase electrical loads (130) for each of the three-phase electrical loads (130) for each of the three-phase electrical loads (130) for each of the single-phase electrical loads (14 ...

7. The energy conversion system according to claim 6, characterized in that the AC voltage providing system (18) comprises an AC voltage generating module (30) and a transformer (32).

8. An electric vehicle (10) comprising an energy conversion system (15), 8. An electric vehicle, characterized in that the energy conversion system (15) is an energy conversion system according to claim 6 or 7.

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