Method for reducing noise in a vehicle's traction circuit power supply system, and associated vehicle traction circuit power supply system

Abstract

Method for reducing noise in a vehicle traction circuit power supply system, and associated vehicle traction circuit power supply system. The invention relates to a method and a power supply system for a vehicle traction circuit, the traction circuit comprising a traction motor (4) and a main inverter (18) adapted to deliver an alternating voltage to supply the traction motor (4), the power supply system (2) comprising a self-contained electrical power source (6) providing a first direct current electrical voltage (V1), connected to a voltage boost converter (8) adapted to deliver a second direct current electrical voltage (V2) to the main inverter.The system includes a control block (24) configured to determine a value for the second DC electrical voltage based on a vehicle operating parameter, either vehicle speed (Vveh) or electrical power (Pcons) consumed or delivered by said traction motor, and to control said voltage boost converter (8) to deliver the determined second DC electrical voltage (V2). Figure 1 for abbreviations.

Description

Title of the invention: Method for reducing noise in a vehicle traction circuit power supply system, and associated vehicle traction circuit power supply system

[0001] The present invention relates to a method for reducing noise in a vehicle traction circuit power supply system and an associated vehicle traction circuit power supply system.

[0002] The invention is in the field of vehicle traction drive, in particular railway vehicles.

[0003] Traction circuit power supply systems are known which include an autonomous electrical power source providing a first direct current electrical voltage, such an electrical power source being for example a battery or a fuel cell, adapted to supply this electrical power to a traction motor via an inverter adapted to deliver an alternating voltage to power the traction motor.

[0004] In some practical cases, it is necessary to add to the power supply system a voltage step-up converter, also called a boost converter or step-up chopper, adapted to deliver at output a second DC electrical voltage higher than the first DC electrical voltage, this second DC electrical voltage allowing nominal operation of the inverter and / or the motor.

[0005] For example, in the case of railway applications, the first DC electrical voltage is less than or equal to 1000 Volts, and the second DC electrical voltage is on the order of 1500 Volts.

[0006] Such a voltage boost converter includes an inductance which produces an electrically based tonal noise, which is particularly troublesome in the case of a passenger transport vehicle, for example a railway vehicle, and more particularly in the case where a plurality of such voltage boost converters are required.

[0007] Noise reduction methods for inductances are known in the prior art, in particular methods for breaking the periodic patterns of the electric current, which are sources of tonal noise.

[0008] The invention relates to a method for reducing noise in a traction circuit power supply system comprising a voltage boost converter. When the vehicle is a passenger transport vehicle, One of the objectives is to reduce the inconvenience caused to passengers by the noise from the electrical power supply system of the traction circuit.

[0009] To this end, the invention proposes, according to one aspect, a method for reducing noise in a traction circuit power supply system of a vehicle, the traction circuit comprising a traction motor and a main inverter adapted to deliver an alternating voltage to power the traction motor, the power supply system comprising an autonomous electrical power source providing a first direct current electrical voltage, connected to a voltage boost converter adapted to deliver a second direct current electrical voltage higher than the first direct current electrical voltage, said voltage boost converter being connected to the input of the main inverter.This method involves determining a value for the second DC electrical voltage, based on a vehicle operating parameter such as vehicle speed or electrical power consumed or delivered by said traction motor, and controlling said voltage boost converter to deliver the determined second DC electrical voltage.

[0010] Advantageously, the method of the invention makes it possible to obtain a reduction in noise as a function of a vehicle operating parameter among the speed of the vehicle and the electrical power consumed or delivered by the traction motor, which makes it possible to increase passenger comfort, in particular at low speed and when stopped in a station.

[0011] The noise reduction method according to the invention may also have one or more of the characteristics below, taken independently or according to all technically feasible combinations.

[0012] The determination involves comparing said vehicle operating parameter to an operating threshold. When the vehicle operating parameter is above the operating threshold, the second DC voltage is set to a nominal voltage value. When the vehicle operating parameter is below the operating threshold, a value for the second DC voltage is calculated based on said operating parameter, so as to reduce the difference between the values ​​of the second DC voltage and the first DC voltage.

[0013] When the vehicle operating parameter is below the operating threshold, the value of the second voltage decreases linearly with respect to the nominal voltage value, according to the vehicle operating parameter until the difference between the values ​​of the second DC electrical voltage and the first DC electrical voltage is zero.

[0014] The vehicle operating parameter is the vehicle speed and said operating threshold is a speed threshold between 20 and 100km / h.

[0015] The operating threshold is an upper operating threshold, the method further comprising a comparison of the vehicle operating parameter to a lower operating threshold, and a zeroing of the difference between the values ​​of the second DC electrical voltage and the first DC electrical voltage when the vehicle operating parameter is less than or equal to the lower operating threshold.

[0016] According to another aspect, the invention relates to a traction circuit power supply system of a noise reduction vehicle, the traction circuit comprising a traction motor and a main inverter adapted to deliver an alternating voltage to power the traction motor, the power supply system comprising a self-contained electrical power source providing a first direct current electrical voltage, connected to a voltage boost converter adapted to deliver a second direct current electrical voltage higher than the first direct current electrical voltage, said voltage boost converter being connected to the main inverter.This system includes a control block configured to determine a value for the second DC electrical voltage based on a vehicle operating parameter such as vehicle speed or electrical power consumed or delivered by said traction motor, and to control said voltage boost converter to deliver the determined second DC electrical voltage.

[0017] Advantageously, this system is configured to implement the noise reduction process, according to all its envisaged variants.

[0018] The traction circuit power supply system of a noise reduction vehicle according to the invention may also have one or more of the following features, taken independently or in any technically feasible combination.

[0019] The voltage boost converter includes an inductor, and two transistor circuits connected to one terminal of said inductor.

[0020] Each of said transistor circuits comprises a power transistor and a diode connected in parallel with said transistor.

[0021] The control block is configured to control, when the operating parameter of the vehicle is below the operating threshold, a value of the second voltage decreasing linearly with respect to the nominal voltage value, according to the operating parameter of the vehicle, until the difference between the values ​​of the second DC electrical voltage and the first DC electrical voltage is zero.

[0022] According to another aspect, the invention relates to a vehicle, in particular a railway vehicle, comprising a traction circuit power supply system for a noise-reducing vehicle as described above.

[0023] Other features and advantages of the invention will become apparent from the description given below, by way of example and not limitation, with reference to the accompanying figures, among which:

[0024] [Fig-1] [Fig.1] is a block diagram of a circuit power supply system traction of a noise-reducing vehicle according to an embodiment;

[0025] [Fig.2] [Fig.2] is a flowchart of the main steps of a process of noise reduction according to an embodiment;

[0026] [Fig.3] [Fig.3] schematically illustrates graphs of the evolution of speeds and tensions over time in an application case.

[0027] The invention will be described below in the case of a railway-type vehicle, for example a train, a metro, a tram.

[0028] Fig. 1 schematically illustrates an electrical power supply system 2 of a vehicle 5. The electrical power supply system 2 provides electricity to a traction motor 4 of the vehicle 5, adapted to drive wheels not shown.

[0029] The power supply system 2 includes a self-contained electrical power source 6, which is for example a battery of accumulators or a fuel cell.

[0030] The electrical power source 6 is adapted to deliver a first electrical voltage VI, which is continuous, and of substantially constant value.

[0031] For example, the first electrical voltage VI delivered is in the order of 800V to 1000V.

[0032] System 2 further includes a voltage step-up converter 8, also known as a boost converter or boost chopper, which is adapted to deliver a second DC electrical voltage V2 higher than the first DC electrical voltage VL

[0033] The value of the second DC electrical voltage V2 is adjustable by control within a certain predefined range. In one embodiment, the adjustment of the second voltage V2, delivered by the boost converter, is carried out via the control of the boost converter's duty cycle (a), which relates the voltages VI and V2 by the following relationship:

[0034] £2=_L V l l-«

[0035] The boost converter 8 has two input terminals, connected to the output terminals of the electrical power source 6.

[0036] This boost converter 8 conventionally comprises an inductor 10, two transistor circuits 12, 14, each of these circuits respectively comprising a transistor 12a, 14a and a diode 12b, 14b. For example, each transistor is of the insulated-gate bipolar type or IGBT, and more generally a power transistor. The transistor circuits 12, 14 are connected in series, with one output terminal of the inductor 10 being connected to a connection point located between the two transistor circuits 12, 14. Thus, each transistor circuit 12, 14 is connected to an output terminal of the inductor 10 by one of its output terminals, the circuits 12, 14 being connected in parallel to a capacitor 16 by another of their output terminals.

[0037] The power supply system 2 is connected to a main inverter 18, also called a traction inverter, the structure of which is not described in detail. The main inverter 18 is connected to the output terminals of the voltage boost converter 8, and is adapted to generate an alternating voltage from the second DC electrical voltage V2 at the input, to power the motor 4.

[0038] The main inverter 18 and the motor 4 form a traction circuit for the vehicle 5.

[0039] In the illustrated example, the motor 4 is three-phase, the main inverter 18 is adapted to provide three phases of electrical power to the motor.

[0040] Alternatively, a different number of phases is conceivable.

[0041] The system 2 is furthermore, in the example illustrated in [Fig.1], connected to a secondary inverter 20, adapted to provide an alternating electrical voltage to a set of auxiliary loads 22 of the vehicle 5, these auxiliary loads including for example an interior lighting system of the vehicle, an interior heating and air conditioning system etc.

[0042] Finally, the system 2 also includes a control block 24, which is configured to implement a noise reduction method. In particular, the control block 24 calculates the value of the second DC electrical voltage V2 and commands the delivery of this second DC electrical voltage V2 to the voltage boost converter 8.

[0043] The control block 24 receives as input the value of the first electrical voltage VI, the vehicle speed Vveh, measured for example by a sensor and transmitted to the control block, and / or the electrical power, denoted Pcons, consumed or delivered by the motor 4 for the vehicle's traction. For example, the power Pcons is the power consumed or delivered by the inverter 18. Hereafter, the traction power will be referred to as the power Pcons (in absolute value) consumed or delivered.

[0044] In one embodiment, the control block 24 comprises an electronic memory 26 and a microprocessor 28; the memory comprises instructions software which, when executed on the microprocessor 28, performs a noise reduction process as described below with reference to [Fig.2].

[0045] The control block 24 implements a determination 40 of the value of the second electrical voltage V2 as a function of a vehicle operating parameter, which is either the vehicle speed Vveh or the vehicle traction power Pcons. It should be noted that the power Pcons and the speed Vveh are related to the power consumed or delivered by the voltage boost converter 8.

[0046] In one embodiment, the chosen operating parameter is the speed of the vehicle.

[0047] Next, the control block 24 implements a control 42 of the voltage boost converter 8 to deliver the second determined electrical voltage V2.

[0048] The determination step 40 includes a substep 44 for acquiring a vehicle operating parameter, which is the vehicle speed Vveh and / or the power Pcons consumed or delivered by the vehicle's traction. In addition, the first electrical voltage VI is also obtained; this is, for example, a measurement.

[0049] Then, during a comparison substep 46, the operating parameter is compared to a predetermined operating threshold, for example the vehicle speed is compared to a predetermined speed threshold Speed_th, for example between 20km / h and 100km / h, and more particularly between 30km / h and 40km / h in one embodiment.

[0050] If the vehicle speed is greater than the speed threshold Speed_th, the comparison substep 46 is followed by a substep 48 of assigning to the second voltage V2 a predetermined nominal voltage value, which is for example the nominal operating value of the main inverter 18. For example, the nominal value is on the order of 1500V.

[0051] If the vehicle speed is below the speed threshold Speed_th, the comparison substep 46 is followed by a substep 50 that calculates a value for the second voltage V2 as a function of the first voltage VI and the vehicle speed Vveh, this voltage value being lower than the nominal voltage value. For example, the value of the second voltage decreases linearly between the nominal voltage value and the first voltage VL

[0052] Thus, during a vehicle traction phase at a speed exceeding the speed threshold, the voltage boost converter 8 delivers a second constant voltage V2 equal to the nominal voltage value. The duty cycle of the voltage boost converter 8 is constant, and the difference between the value of the second voltage V2 and the value of the first voltage V1 is constant.

[0053] During a braking or starting phase, if the vehicle speed is less than or equal to the speed threshold Speed_th, the second voltage V2 is less than the nominal voltage value.

[0054] For example, in one embodiment, the value of the second voltage V2 decreases linearly with speed up to a minimum speed Vmin, the difference between the second voltage value V2 and the first voltage value V1 being equal to 0 for this speed Vmin.

[0055] Advantageously, the noise generated by the inductance 10 of the voltage boost converter 8 is reduced, because the noise amplitude depends on the difference between the output voltage (i.e. the second electrical voltage V2) and the input voltage (i.e. the first electrical voltage VI), and this noise amplitude is zero when this difference reaches the value zero.

[0056] Alternatively, the vehicle operating parameter taken into consideration is the power consumed or delivered by the traction motor, and power thresholds are used in substeps 46, 48 and 50 to calculate the voltage V2. For example, the voltage V2 will be at its nominal value, on the order of 1500V, when the traction power is high, and the value of the second voltage V2 can be decreased linearly between the nominal value and the first voltage VI, when the traction power is reduced.

[0057] Thus, more generally, the process implements a vehicle operating parameter (vehicle speed or power consumed or delivered by the traction motor), which is compared to an operating threshold (speed threshold or power threshold).

[0058] In one embodiment, during the comparison 46, the vehicle speed is compared to a first upper speed threshold and a second lower speed threshold, and if it is lower than the lower speed threshold, the difference between the second voltage value V2 and the first voltage value VI is set to 0. If the vehicle speed is between the first speed threshold and the second speed threshold, a calculation of the value of the second voltage is implemented, as indicated above.

[0059] Similarly, if the operating parameter used is the traction power of the vehicle, this operating parameter is compared respectively to a first operating threshold (e.g. first power threshold) higher and to a second operating threshold (e.g. power threshold) higher.

[0060] Fig. 3 schematically illustrates the operation described above when the chosen operating parameter is the vehicle speed, by means of the parallel representation of the time evolution graphs of the vehicle speed (graph G1), of the first voltage VI and second voltage V2 (graphs F2, G2) and of the operating state of the voltage boost converter (graph G3).

[0061] Graphs Gl, F2, G2 and G3 are represented in parallel, with the time axes on the abscissa being concordant.

[0062] During a first time period, between a first instant (instant 0) and an instant tb the vehicle travels at maximum speed Vmax, the second voltage V2 is at the nominal value Vnominai e, the voltage boost converter is in operation (mode “ON”).

[0063] During a second time period, between the time instant ti and the time instant t2, the speed of the vehicle decreases between Vmax and the speed threshold noted VT h, but as long as the speed threshold VT h is not reached, the second voltage V2 is maintained at the nominal voltage value.

[0064] As soon as the vehicle speed reaches and falls below the speed threshold VT h, during a third time period between time t2 and time t3, the second voltage (graph G2) decreases until it reaches the first voltage VI, which is constant. The boost converter is still operating (in "ON" mode) during the third time period. At time t3, the vehicle speed is equal to a minimum speed Vmin.

[0065] During a fourth time period, between time instant t3 and time instant t4, the vehicle continues braking between speed Vmin and zero. During this fourth period, the voltage difference between the second voltage V2 and the first voltage VI is zero, and the boost converter is not operating (mode “OFF”).

[0066] The vehicle remains stationary, the voltage difference between the second voltage V2 and the first voltage VI is zero, and the voltage boost converter is not in operation (mode “OFF”) for a fifth time period between time t4 and time t5.

[0067] During a sixth time period, between time t5 and time t6, the vehicle restarts, its speed increases from 0 to Vmin, but the voltage difference between the second voltage V2 and the first voltage VI remains zero, and the voltage boost converter is not in operation (mode “OFF”).

[0068] During a seventh time period, between time t6 and time t7, the value of the second voltage V2 is increased linearly as a function of the speed of the vehicle which increases up to the speed threshold VT h- The voltage boost converter is in operation (mode “ON”) during the seventh time period.

[0069] Finally, during an eighth time period between time t7 and time t8, the speed of the vehicle continues to increase up to the maximum speed Vmax, but the second voltage value V2 remains at the nominal voltage value Vnominaie, the voltage boost converter being in operation (mode “ON”).

[0070] Thus, advantageously, the second electrical voltage V2 supplied is lower than the nominal value only during phases in which the speed of the vehicle is below the speed threshold, which makes it possible to reduce the noise of the voltage boost converter while maintaining a satisfactory operating level of the motor 4.

[0071] When the voltage boost converter is not in operation (in "OFF" mode), the power source 6 can continue to supply the main inverter (or traction inverter) 18 and the secondary inverter 20 through diode 12b, without receiving a control signal from block 24.

[0072] According to one variant, the voltage boost converter is kept in operation (mode “ON”) during all time periods, including between time t3 and time t6, because despite the zero difference between the second voltage V2 and the first voltage VI, controlled by the control block 24, braking energy is recovered from the motor 4 to be stored in the source 6. Transistor 12a is kept for this purpose in a permanent conductive state, and transistor 14a in a non-conductive state.

Claims

Demands

1. A method for reducing noise in a vehicle traction circuit power supply system, the traction circuit comprising a traction motor (4) and a main inverter (18) adapted to deliver an alternating voltage to supply the traction motor (4), the power supply system (2) comprising a self-contained electrical power source (6) providing a first direct current electrical voltage (VI), connected to a voltage boost converter (8) adapted to deliver a second direct current electrical voltage (V2) greater than the first direct current electrical voltage (VI), said voltage boost converter (8) being connected to the input of the main inverter (18), characterized in that it comprises a determination (40) of a value of the second direct current electrical voltage (V2),depending on a vehicle operating parameter such as vehicle speed or electrical power consumed or delivered by said traction motor, and a control (42) of said voltage boost converter to deliver the second determined DC electrical voltage (V2).

2. A method according to claim 1, wherein said determination (40) comprises a comparison (46) of said vehicle operating parameter to an operating threshold, and when the vehicle operating parameter is above the operating threshold, the second DC electrical voltage is fixed (48) at a nominal voltage value, when the vehicle operating parameter is below the operating threshold, a value of the second DC electrical voltage (V2) is calculated (50) as a function of said operating parameter, so as to reduce a difference between the values ​​of the second DC electrical voltage and the first DC electrical voltage.

3. A method according to claim 2, wherein, when the vehicle operating parameter is below the operating threshold, the value of the second voltage decreases linearly with respect to the nominal voltage value, as a function of the vehicle operating parameter, until the difference between values of the second DC electrical voltage and the first DC electrical voltage is zero.

4. A method according to any one of claims 2 or 3, wherein said vehicle operating parameter is the vehicle speed and said operating threshold is a speed threshold between 20 and 100 km / h.

5. A method according to any one of claims 2 to 4, wherein said operating threshold is an upper operating threshold, the method further comprising a comparison of the vehicle operating parameter to a lower operating threshold (Vmin), and a zeroing of the difference between the values ​​of the second DC electrical voltage and the first DC electrical voltage when the vehicle operating parameter is less than or equal to the lower operating threshold.

6. Traction circuit power supply system of a noise-reducing vehicle, the traction circuit comprising a traction motor (4) and a main inverter (18) adapted to deliver an alternating voltage to power the traction motor (4), the power supply system comprising a self-contained electrical power source (6) providing a first direct current electrical voltage (VI), connected to a voltage boost converter (8) adapted to deliver a second direct current electrical voltage (V2) higher than the first direct current electrical voltage, said voltage boost converter (8) being connected to the main inverter (18),characterized in that it comprises a control block (24) configured to determine a value of the second DC electrical voltage as a function of a vehicle operating parameter such as vehicle speed or electrical power consumed or delivered by said traction motor, and to control said voltage boost converter (8) to deliver the determined second DC electrical voltage.

7. System according to claim 6, wherein said voltage boost converter comprises an inductor (10), and two transistor circuits (12, 14) connected to one terminal of said inductor.

8. System according to claim 7, wherein each of said transistor circuits (12, 14) comprises a power transistor (12a, 14a) and a diode (12b, 14b) connected in parallel with said transistor.

9. System according to any one of claims 6 to 8, wherein the control block (24) is configured to control, when the vehicle operating parameter is below an operating threshold, a value of the second voltage decreasing linearly with respect to the nominal voltage value, depending on the vehicle operating parameter, until the difference between the values ​​of the second DC electrical voltage and the first DC electrical voltage is zero.

10. Vehicle, in particular a railway vehicle, comprising a motor and a traction circuit power supply system of a noise-reducing vehicle conforming to claims 6 to 9.

Images