Arrangement for propelling a hybrid rail vehicle

Abstract

The invention relates to an arrangement for driving a hybrid rail vehicle, in which the rail vehicle comprises a DC link (DC), a first converter (VQS1), a second converter (PWR1), and a battery arrangement (BAT1, BAT2). The first converter (VQS1) is connected to an energy source (OL) on its input side and to the DC link (DC) on its output side. The first converter (VQS1) can be switched such that energy from the first energy source (OL) is fed into the DC link (DC). The second converter (PWR1) is connected to the DC link (DC) on its input side and to traction motors (FM1) of the rail vehicle on its output side. The second converter (PWR1) can be switched such that energy from the DC link (DC) is fed to the traction motors (FM1) to drive the rail vehicle.The battery arrangement (BAT1, BAT2) is connected in parallel and directly to the DC intermediate circuit (ZK), so that energy from the battery arrangement (BAT1, BAT2) goes directly into the DC intermediate circuit (ZK).

Description

The invention relates to an arrangement for driving a hybrid rail vehicle which draws drive energy from a DC voltage intermediate circuit.FIG. 3 shows an associated drive principle on a known hybrid rail vehicle.An electrical energy supply feeds alternating current via an overhead line OL or via a contact wire into a primary winding PW of a transformer TR which is arranged in the rail vehicle.The primary winding PW of the transformer TR is coupled to a first secondary winding SW1 of the transformer TR to convert the supplied alternating current.The first secondary winding SW 1 is connected on the output side to a first four-quadrant chopper VQS 1, which is operated as an AC-DC converter.The first four-quadrant actuator VQS 1 ensures that the alternating current supplied to it is converted into a direct current and this subsequently reaches a direct voltage intermediate circuit ZK via a suction circuit SK connected in parallel with the first four-quadrant actuator VQS 1.The primary winding PW of the transformer TR is coupled to a second secondary winding SW2 of the transformer TR to also convert supplied alternating current.The second secondary winding SW 2 is connected on the output side to a second four-quadrant chopper VQS 2, which is operated as an AC-DC converter.The second four-quadrant controller VQS2 ensures that the alternating current supplied to it is converted into a direct current and this subsequently reaches the DC voltage intermediate circuit ZK via the suction circuit SK, which is likewise connected in parallel with the second four-quadrant controller VQS2.The suction circuit SK comprises a coil L and a capacitor C connected in series and forming a filter. The suction circuit SK filters out twice the mains frequency of the overhead line-based supply in the DC voltage intermediate circuit ZK.The DC voltage intermediate circuit ZK is also connected to a battery BAT connected in parallel with it, which battery likewise feeds direct current into the DC voltage intermediate circuit ZK or draws direct current from there via associated choke coils DS and via a downstream DC-DC converter DCDCW.The DC voltage intermediate circuit ZK is connected on the output side via two pulse inverters PWR 1, PWR 2 connected in parallel with traction motors FM 1, FMn. The pulse inverters PWR 1, PWR 2 convert direct current or direct voltage of the direct voltage intermediate circuit ZK into alternating current, which then reaches the traction motors FM 1, FMn of the rail vehicle in order to rub the latter.The pulse inverters PWR1, PWR2 regulate slip and torque of the driven wheels.The DC voltage intermediate circuit ZK is also connected on the output side via an auxiliary operating converter HBU to a further transformer Aux-Trafo. The auxiliary-mode converter HBU converts DC voltage of the DC voltage intermediate circuit ZK into AC voltage or AC current, which then reaches auxiliary modes of the rail vehicle via the further transformer Aux transformer.The auxiliary-mode converter HBU supplies, for example, a three-phase alternating-current on-board power supply system using the further transformer Aux-Trafo, which is also referred to as auxiliary-mode transformer.A mains return current of the DC voltage intermediate circuit ZK, of the common phase SK, of the two four-quadrant actuators VQS 1, VQS 2, of the battery BAT, of the two pulse inverters PWR 1, PWR 2 and of the auxiliary-operated transformer Aux-Trafo is combined via a bus line SL and subsequently transmitted to a rail SCH.Via the four-quadrant controller VQS 1, VQS 2, a control of an intermediate circuit voltage and of an associated power factor in the AC supply takes place.The battery BAT is a battery system consisting of a plurality of parallel strings.The two four-quadrant controllers VQS 1, VQS 2 operate as active rectifiers via the overhead line during grid-based operation and regulate the intermediate circuit voltage and the power factor in the overhead line grid OL as a function of an incoming power in the DC intermediate circuit ZK and an extracted power from the DC intermediate circuit ZK. The charging power into the battery is controlled by the DC-DC converter DCDCW.In addition, the DC voltage intermediate circuit ZK can be supplied with additional energy (i.e. "boosted") from the battery BAT via the DC-DC converter DCDCW, which is operated as a boost converter, in order to enable an increased power extraction briefly compared to the power supply of the two four-quadrant converters VQS 1, VQS 2 into the DC voltage intermediate circuit ZK.In the battery-based operation of the rail vehicle, the two four-quadrant actuators VQS 1, VQS 2 are switched off. The DC-DC converter DCDCW now regulates the voltage in the DC voltage intermediate circuit ZK with the participation of the battery BAT, and the DC-DC converter DCDCW is operated as a step-up converter.During electrical braking or recuperation, the DC-DC converter DCDCW operates as a step-down converter in order to bring released energy from the DC voltage intermediate circuit ZK into the battery BAT or in order to charge it.In the DC voltage intermediate circuit ZK, a high-resistance center ground EA is realized via two parallel-connected resistors R. The voltage to ground at the battery is obtained via the DC-DC converter DCDCW.In summary, the hybrid rail vehicle uses two power sources to be driven, namely the battery BAT and the AC-based overhead line OL. Both feed energy into the intermediate circuit ZK, wherein the battery BAT is also used during regenerative or regenerative braking in order to absorb energy which is released or to temporarily store it.The DC-DC converter DCDCW is necessary in the hybrid operation to set a predetermined voltage between the DC link ZK and the battery BAT. In general, a constant voltage of 1.5 kV to 4 kV is set in the DC voltage intermediate circuit.The DC-DC converter DCDCW consists of transistors, diodes and inductances and must be designed for connecting the battery BAT to the DC voltage intermediate circuit ZK for full charging and discharging power of the battery BAT.The necessary use of the DC-DC converter DCDCW entails the following disadvantages:additional losses arise which reduce the range of the rail vehicle during battery-assisted operation,additional cooling requirements are required,only limited and thus valuable installation space is required,the rail vehicle has additional weight, andIn total, manufacturing and maintenance costs of the rail vehicle increase.It is therefore the object of the present invention to specify an improved arrangement for driving a hybrid rail vehicle which draws drive energy from a DC voltage intermediate circuit, which arrangement overcomes the disadvantages mentioned above.This object is achieved by the features of claim 1. Advantageous further developments are specified in the dependent patent claims.The invention relates to an arrangement for driving a hybrid rail vehicle, in which the rail vehicle has a DC voltage intermediate circuit, a first converter, a second converter and a battery arrangement.The first converter is connected or connectable on the input side to an energy source and on the output side to the DC voltage intermediate circuit. It can be switched in such a way that energy of the first energy source reaches the DC voltage intermediate circuit.The second converter is connected on the input side to the DC voltage intermediate circuit and on the output side to traction motors of the rail vehicle or can be connected. It can be switched in such a way that energy from the DC voltage intermediate circuit reaches the traction motors in order to drive the rail vehicle via the latter.The battery arrangement is connected in parallel and directly (i.e. without the involvement of an additional converter) to the DC voltage intermediate circuit, so that energy from the battery arrangement reaches directly into the DC voltage intermediate circuit.The battery arrangement has a first and a second battery which are connected in series to one another and form a series circuit.A first end of the series circuit is connected to the DC voltage intermediate circuit, while a second end of the series circuit is connected to a compensation potential, which is preferably formed by a collecting line, for a return current.The compensation potential preferably connects the two converters, the battery arrangement and the DC voltage intermediate circuit to one another.In grid operation, the return current flows back to a rail on which the rail vehicle is travelling via the first converter, which is also referred to here as the feeding converter, and possibly via further components (for example a transformer connected to the first converter).The DC voltage intermediate circuit has no direct connection to the rail; only via the high-resistance center ground described below is a connection ground=ground=rail realized.The connection between the two batteries is connected to ground via a high-resistance resistor, so that a high-resistance center point grounding is realized.In a preferred development, the energy source is AC-based. For example, corresponding energy is formed or made available with the aid of an overhead line or a contact wire or with the aid of a diesel engine-generator combination.In a preferred development, the energy source is DC-based. For example, corresponding energy is made available to the DC voltage intermediate circuit by means of an overhead line or a contact wire via a converter.In a preferred development, in the case of an AC-based energy source, the energy source is connected to the first converter via a transformer.In a preferred development, the first converter is a four-quadrant chopper which converts an alternating current supplied to it into a direct current for the DC voltage intermediate circuit.In a preferred development, the second converter is a pulse inverter which converts a direct current supplied to it from the DC voltage intermediate circuit into an alternating current for the traction motors.In a preferred development, by operating the battery arrangement at the DC voltage intermediate circuit, a battery charging current in AC-based operation is regulated by the first converter and by the second converter during recuperation.Due to the present invention, a DC-DC converter required up to now for connecting the battery to the DC voltage intermediate circuit is no longer required.Due to the present invention, a previously required suction circuit or filter, which would be connected in parallel to the DC voltage intermediate circuit, is no longer absolutely required.The present invention avoids the above-mentioned disadvantages:(Heat) losses are avoided, which leads to the range of the hybrid rail vehicle being increased during battery-based operation.Furthermore, the present invention saves valuable installation space, avoids additional weight, and saves manufacturing and maintenance costs of the rail vehicle.The present invention enables simple dimensioning of required components:The constant voltage in the DC voltage intermediate circuit of a rail vehicle with overhead line feed (primary energy feed) is typically 1.5 kV to 4 kV. These voltages make possible a reasonable design of four-quadrant actuator, pulse inverter and traction motor.Lower voltages in the DC voltage intermediate circuit would lead, according to the known prior art, to an over-dimensioning of four-quadrant actuators, pulse inverters and traction motors at the required traction powers.This is avoided by the present invention despite the integration of a traction battery, so that the meaningful design of four-quadrant actuators, pulse inverters and traction motors can be maintained.By the present invention, an original insulation configuration of the battery of, for example, 1 kV can be maintained. Without the high-resistance center ground described above, an adapted battery system having an insulation design of 2 kV would be necessary, which would lead to increased installation space requirement, lower energy density of the battery or of the energy store and increased costs.The invention is explained in more detail below with the aid of a drawing. The following shows: FIG. 1 shows an exemplary embodiment of the invention, FIG. 2 shows a detailed explanation of voltages at the battery with reference to FIG. 1, and FIG. 3 shows the prior art described in the introduction.FIG. 1 shows an embodiment of the invention on the basis of a hybrid rail vehicle which uses energy from an AC overhead line and from a battery for driving.An electrical energy supply feeds alternating current via an overhead line OL or via a contact wire into a primary winding PW of a transformer TR which is arranged in the rail vehicle.The primary winding PW of the transformer TR is coupled to a first secondary winding SW1 of the transformer TR to convert the supplied alternating current.The first secondary winding SW 1 is connected on the output side to a first four-quadrant chopper VQS 1, which is operated as an AC-DC converter.The first four-quadrant chopper VQS 1 ensures that the alternating current supplied to it is converted into a direct current and this subsequently reaches a direct voltage intermediate circuit ZK.The primary winding PW of the transformer TR is coupled to a second secondary winding SW2 of the transformer TR to also convert supplied alternating current.The second secondary winding SW 2 is connected on the output side to a second four-quadrant chopper VQS 2, which is operated as an AC-DC converter.The second four-quadrant chopper VQS 2 ensures that the alternating current supplied to it is converted into a direct current and this subsequently reaches the DC voltage intermediate circuit ZK.The DC voltage intermediate circuit ZK is connected to a battery arrangement connected in parallel, which has two batteries BAT 1, BAT 2.The two batteries BAT 1, BAT 2 are connected in series to one another and form a series circuit.The DC voltage intermediate circuit ZK is connected on the output side via two pulse inverters PWR 1, PWR 2 connected in parallel with traction motors FM 1, FMn. The pulse inverters PWR 1, PWR 2 convert direct current of the DC intermediate circuit ZK into alternating current, which then reaches the traction motors FM 1, FMn of the rail vehicle in order to rub the latter.The pulse inverters PWR1, PWR2 regulate slip and torque of the driven wheels.The DC voltage intermediate circuit ZK is also connected on the output side via an auxiliary operating converter HBU to a further transformer Aux-Trafo. The auxiliary-mode converter HBU converts direct current of the DC voltage intermediate circuit ZK into alternating current, which then reaches auxiliary modes of the rail vehicle via the further transformer Aux transformer in a manner adapted to the auxiliary modes of the rail vehicle.The auxiliary-mode converter HBU supplies, for example, a three-phase alternating-current on-board power supply system using the further transformer Aux-Trafo, which is also referred to as auxiliary-mode transformer.A first end of the battery series circuit is connected to the DC voltage intermediate circuit ZK, while a second end of the series circuit is connected to a compensation potential for a reverse current.The compensation potential connects the two four-quadrant actuators VQS 1, VQS 2, the battery arrangement, the DC voltage intermediate circuit ZK and the two pulse inverters PWR 1, PWR 2 to one another in the form of a bus line SL.A return current, which is caused by these elements, is formed via the collecting line SL. In grid operation, the return current flows back via the converters VQS 1, VQS 2 and via the transformer TR connected to the converters to a rail SCH on which the rail vehicle is traveling.The connection between the two batteries BAT 1, BAT 2 is grounded via a high-resistance resistor RW (order of magnitude of several kilo-ohms), so that a high-resistance center ground EA is realized.The four-quadrant controllers VQS 1, VQS 2 are used to regulate an intermediate circuit voltage. An associated power factor in the AC supply is adjusted by the four-quadrant converters VQS 1, VQS 2.The two four-quadrant controllers VQS 1, VQS 2 operate as active rectifiers via the overhead line during grid-based operation and regulate a charging power for the batteries BAT 1 and BAT 2 as a function of an incoming power in the DC voltage intermediate circuit ZK and an extracted power from the DC voltage intermediate circuit ZK.In addition, the DC voltage intermediate circuit ZK can be supplied with additional energy (i.e. "boosted") from the battery arrangement in order to enable an increased power extraction for a short time compared to the power supply of the DC voltage intermediate circuit ZK.In the battery-based operation of the rail vehicle, the two four-quadrant actuators VQS 1, VQS 2 are switched off.In summary, the hybrid rail vehicle uses two energy sources to be driven - namely the batteries BAT 1 and BAT 2 or the AC-based overhead line OL. Both feed energy into the intermediate circuit ZK, wherein the batteries BAT 1, BAT 2 are also used during regenerative or regenerative braking in order to absorb energy which is released or to temporarily store it.The pulse inverters PWR 1, PWR 2 supply the traction motors FM and regulate slip and torque.The auxiliary converter (HBU) supplies the three-phase alternating current on-board power supply via the auxiliary transformer (Aux-Transformer).FIG. 2 shows a detailed explanation with respect to voltages at the batteries BAT 1 and BAT 2 with reference to FIG. 1.The series or series connection of the two batteries BAT 1, BAT 2 produces a maximum total voltage at their external terminals of 1 kV+1 kV=2 kV.This voltage is sufficient to operate the battery arrangement, consisting of the two batteries BAT 1, BAT 2, directly at the DC voltage intermediate circuit ZK and to achieve a reasonable design of the elements four-quadrant chopper VQS 1, VQS 2, the pulse-controlled inverters PWR 1, PWR 2, the auxiliary variable-speed converter HBU and the traction motors FM 1, FM 2.The two batteries BAT 1, BAT 2 are furthermore insulated from ground only for 1 kV; a high-resistance ground connection or center ground EA is realized at the center point of the series or series connection.Thus, the battery BAT1 is max. 1 kV to ground, while in the case of battery BAT2'-1 kV is to ground, so that an original insulation configuration for 1 kV can be maintained for the battery arrangement.Without the center ground EA at the center of the series circuit, an adapted battery arrangement with an insulation configuration for 2 kV would be necessary in comparison with the known prior art.To minimize fault currents in the battery arrangement during ground fault, an additional resistor (on the order of several kilo-ohms) is inserted as part of the center ground EA.The "high-resistance center ground" EA thus produced permits a simple ground fault in the DC voltage intermediate circuit ZK.In the DC voltage intermediate circuit ZK, comparable resistance conditions to earth prevail as a result of the high-resistance center ground of the battery arrangement as in the prior art described at the beginning.By operating the battery arrangement at the DC voltage intermediate circuit ZK and by eliminating the DC-DC converter required hitherto, a battery charging current in AC-based operation is regulated by the four-quadrant controllers VQS 1, VQS 2 and by the pulse inverters PWR 1, PWR 2 during recuperation.The voltage in the DC voltage intermediate circuit ZK corresponds to the above-mentioned battery terminal voltage both during charging and during discharging.In the event of the optional absence of an absorption circuit, the battery arrangement receives a pulsating intermediate circuit power from the two four-quadrant actuators VQS 1, VQS 2.

Claims

Arrangement for driving a hybrid rail vehicle, - in which a rail vehicle has a DC voltage intermediate circuit (ZK), a first converter (VQS1), a second converter (PWR1) and a battery arrangement (BAT1, BAT2), - in which the first converter (VQS1) can be connected on the input side to an energy source (OL) and is connected on the output side to the DC voltage intermediate circuit (ZK), and the first converter (VQS1) can be switched in such a way that energy of the first energy source (OL) reaches the DC voltage intermediate circuit (ZK), in which the second converter (PWR1) is connected on the input side to the DC voltage intermediate circuit (ZK) and can be connected on the output side to traction motors (FM1) of the rail vehicle, and the second converter (PWR1) can be switched in such a way that energy from the DC voltage intermediate circuit (ZK) reaches the traction motors (FM1) in order to drive the rail vehicle via the latter, - in which the battery arrangement (BAT1, BAT2) is connected in parallel and directly to the DC voltage intermediate circuit (ZK), such that energy from the battery arrangement (BAT1, BAT2) reaches directly into the DC voltage intermediate circuit (ZK).Arrangement according to Claim 1, - in which the battery arrangement (BAT1, BAT2) has a first battery (BAT1) and a second battery (BAT2), which are connected in series to one another and form a series circuit, - in which a first end of the series circuit is connected to the DC voltage intermediate circuit (ZK), while a second end of the series circuit is connected to a compensation potential for a reverse current.Arrangement according to Claim 2, in which the compensation potential connects the two converters (VQS1, PWR1), the battery arrangement (BAT1, BAT2) and the DC voltage intermediate circuit (ZK) to one another, the reverse current being caused by these elements.Arrangement according to Claim 2 or 3, in which a connection between the two batteries (BAT1, BAT2) is connected to ground via a high-resistance resistor in order to realize a high-resistance centre ground.Arrangement according to one of the preceding claims, in which the energy source is AC-based, wherein corresponding energy is provided with the aid of an overhead line (OL) or a contact wire or with the aid of a diesel engine-generator combination.Arrangement according to Claim 5, in which the energy source is connected to the first converter (VQS1) via a transformer (TR).Arrangement according to Claim 6, in which the first converter (VQS1) is a four-quadrant chopper which converts an alternating current supplied to it into a direct current for the DC voltage intermediate circuit (ZK).Arrangement according to one of Claims 5 to 7, in which the second converter (PWR1) is a pulse inverter which converts a direct current supplied to it from the DC voltage intermediate circuit (ZK) into an alternating current for the traction motors (FM1).Arrangement according to one of Claims 6 to 8, in which, by the operation of the battery arrangement (BAT1, BAT2) at the DC voltage intermediate circuit (ZK), a battery charging current in AC-based operation is regulated by the first converter (VQS1) and by the second converter (PWR1) during recuperation.Arrangement according to one of the preceding claims, in which the energy source is DC-based, wherein corresponding energy is provided with the aid of an overhead line (OL) or a contact wire and the energy source has a potential separation between overhead line (OL) and DC voltage intermediate circuit.Rail vehicle having an arrangement according to one of Claims 1 to 10.

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