DC-DC CONVERTER

Abstract

The DC-DC converter (102) comprises: - a positive input terminal (PA) and a negative input terminal (NA); - a positive output terminal (PB) and a negative output terminal (NB); - several branches (Br1, Br2) each comprising a capacitor (C1, C2); - several interconnection circuits (I1, I2) respectively associated with branches (Br1, Br2) and each designed to alternatively: connect the associated branch (Br1, Br2) between the input terminals (PA, NA) to charge the capacitance (C1, C2) from the positive input terminal (PA) so that the capacitance (C1, C2) has a voltage (VC1, VC2), and connect, between the output terminals (PB, NB), the branch (Br1, Br2) associated with the continuation of the input terminals (PA, NA) so that the voltage of the capacitance (VC1, VC2) is added to a DC input voltage (VA) present between the input terminals (PA, NA), to discharge the capacitance (C1, C2) to the positive output terminal (PB);and - a control device (104) designed to control the interconnection circuits (I1, I2) in a phase-shifted manner. Figure for the abbreviation: Fig. 1;

Description

Title of the invention: DC-DC CONVERTER Technical field of the invention

[0001] The present invention relates to a DC-DC converter and a mobility device comprising such a DC-DC converter.

[0002] A mobility device is, for example, a motorized land vehicle, a train, an aircraft, or a drone. A motorized land vehicle is, for example, a car, a motorcycle, a motorized bicycle, or a motorized wheelchair. Technological background

[0003] A DC-DC converter comprising: is known from the prior art - a positive input terminal and a negative input terminal; - a positive output terminal and a negative output terminal; - a branch with a capacity; - an interconnection circuit designed to alternatively: • Connect the branch between the input terminals to charge the capacitor from the positive input terminal so that the capacitor exhibits a voltage, and • Connect the branch following the input terminals between the output terminals so that the capacitor voltage is added to a DC input voltage, to discharge the capacitor towards the positive output terminal; and - a control device designed to control the interconnection circuit.

[0004] Thus, in the first configuration, the capacitor can be charged by a DC input voltage source connected between the input terminals. In the second configuration, the voltage of the capacitor is added to that of the DC input voltage source to supply current to the positive output terminal, thereby regulating the DC output voltage present between the output terminals to a value higher than that of the DC input voltage.

[0005] Thus, current is supplied only when the interconnection circuit is in the second configuration and not in the first, which implies significant current oscillations.

[0006] It may therefore be desirable to provide a DC-DC converter which makes it possible to overcome at least some of the aforementioned problems and constraints. Summary of the invention

[0007] A DC-DC converter is therefore proposed comprising: - a positive input terminal and a negative input terminal; - a positive output terminal and a negative output terminal; - several branches, each with a capacity; - several interconnection circuits respectively associated with the branches and each designed to alternately: • Connect the associated branch between the input terminals to charge the capacitor from the positive input terminal so that the capacitor exhibits a voltage, and • Connect, between the output terminals, the branch associated with the sequence of input terminals so that the voltage across the capacitor adds to a DC input voltage present between the input terminals, to discharge the capacitor towards the positive output terminal; and - a control device designed to control interconnection circuits in a phase-shifted manner.

[0008] Thanks to the invention, since the interconnection circuits are controlled in a phase-shifted manner, when one of them is in the first configuration, another is in the second configuration and current is therefore supplied to the positive output terminal.

[0009] The invention may further include one or more of the following optional features, according to any technically possible combination.

[0010] Optionally, each branch includes an inductance in series with the capacitance of the branch in question.

[0011] Optionally also, for each interconnection circuit, each alternation between the two configurations is carried out at a frequency and according to a duty cycle, and in which the control device is designed, in order to control the DC output voltage, to keep the duty cycle constant but to change the frequency.

[0012] Optionally, the control device is also designed to maintain the alternating frequency above a resonance frequency of each of the branches.

[0013] Optionally also, each interconnection circuit includes two controllable switches connected to each other at a midpoint and together between the input terminals and two other switches connected to each other at a midpoint and together between the positive terminals, and the branch is connected between the midpoints.

[0014] Optionally, the other switches are diodes conducting towards the positive output terminal.

[0015] Optionally, the branches and interconnection circuits may be two, three, or four in number.

[0016] Optionally also, for each interconnection circuit, each alternation between the two configurations extends over a period, the latter having the same duration, and the periods are offset by the duration of the period divided by N, N being the number of branches and interconnection circuits.

[0017] A mobility device comprising a DC-DC converter according to the invention is also proposed. Brief description of the figures

[0018] The invention will be better understood with the aid of the following description, given solely by way of example and made with reference to the accompanying drawings in which: - [Fig. 1] is an electrical diagram of an electrical circuit comprising a DC-DC converter according to the invention, - Figure [Fig. 2] reproduces the electrical diagram of Figure [Fig. 1], in the case where two interconnection circuits are in a first configuration, - Figure 3 reproduces the electrical diagram of Figure 1, in the case where the two interconnection circuits are in a second configuration. - [Fig. 4] is a timing diagram illustrating an example of alternating configurations of the two interconnection circuits, and - [Fig.5] is a timing diagram illustrating an example of alternating configuration of three interconnection circuits. Detailed description of the invention

[0019] With reference to [Fig.1], an electrical circuit 100 according to the invention will now be described.

[0020] The electrical circuit 100 first includes a DC input voltage source SA designed to provide a DC input voltage VA.

[0021] The electrical circuit 100 further includes a load Z designed to be powered by a DC output voltage VB greater than the DC input voltage VA. The load Z may, for example, include another DC voltage source.

[0022] The electrical circuit 100 further includes a DC-DC converter 102 designed to convert the input DC voltage VA into the output DC voltage VB.

[0023] The DC-DC converter 102 thus includes, firstly, a positive input terminal PA and a negative input terminal NA between which the input DC voltage source SA is intended to be connected to provide the input DC voltage VA. Preferably, the DC-DC converter 102 includes an input capacitor CE between the input terminals PA and NA.

[0024] The DC-DC converter 102 further comprises a positive output terminal PB and a negative output terminal NB between which the load Z is intended to be connected to receive the DC output voltage VB. Preferably, the DC-DC converter 102 comprises an output capacitor CS between the output terminals PB and NB.

[0025] The DC-DC converter 102 further comprises several branches Brl, Br2, each comprising a capacitance Cl, C2. Preferably, each branch Brl, Br2 also comprises an inductance Ll, L2 in series with the capacitance Cl, C2 of that branch. This creates a resonance between the capacitance Cl, C2 and the inductance Ll, L2, at a resonance frequency Fl, F2: Fl = 1 / VL1 and F2 = 1 / VL2C2. The inductance Ll, L2 also allows current to flow through the capacitance Cl, C2. Preferably, the capacitances Cl, C2 have the same value, as do the inductances Ll, ​​L2.

[0026] The DC-DC converter 102 further comprises several interconnection circuits II, 12 respectively associated with branches Br1, Br2. Each of the interconnection circuits II, 12 is designed to alternatively connect the branch according to two configurations which will be detailed later.

[0027] For example, as in the illustrated example, each interconnection circuit II, 12 comprises two controllable switches Q1A, Q1B and Q2A, Q2B connected to each other at a midpoint M1, M2 and together between the input terminals PA, NA, and two switches connected to each other at a midpoint M'1, M'2 and together between the positive terminals PA, PB. These latter switches are, for example, as in the illustrated example, diodes D1A, D1B and D2A, D2B conducting towards the positive output terminal PB. The branch Br1, Br2 is then connected between the midpoints M1, M'1 and M2, M'2.

[0028] Each switch is preferably semiconductor, such as, for example, a metal-oxide gate field-effect transistor (MOSFET), a silicon metal-oxide gate field-effect transistor (Si MOSFET), a silicon carbide metal-oxide gate field-effect transistor (SiC MOSFET), an insulated gate bipolar transistor (IGBT), or a gallium nitride field-effect transistor (GaN FET).

[0029] The DC-DC converter 102 then includes a control device 104 designed to control the interconnection circuits II, 12 so that each alternates between its two configurations, in a phase-shifted manner as will be detailed later. For example, as in the illustrated example, the control device 104 is designed to control the controllable switches Q1A, Q1B and Q2A, Q2B.

[0030] With reference to [Fig. 2], the interconnection circuits II, 12 are shown in their first configuration. In this configuration, the interconnection circuit II, 12 connects the branch Brl, Br2 between the input terminals PA, NA to charge the capacitor Cl, C2 from the positive input terminal PA so that the capacitor Cl, C2 has a voltage VC1, VC2. For example, as in the illustrated example, the controllable switch Q1B is closed, while the controllable switch Q2b is open. Thus, the diode Dlc, D2C is conducting, while the diode D1d, D2d is reverse-biased.

[0031] With reference to [Fig. 3], the interconnection circuits II, 12 are shown in their second configuration. In this configuration, the interconnection circuit II, 12 connects the Brl, Br2 branch following the input terminals PA, NA so that the voltage VC1, VC2 of the capacitor Cl, C2 is added to the input voltage VA. Furthermore, the input terminals PA, NA and the Brl, Br2 branch are connected between the output terminals PB, NB to discharge the capacitor Cl, C2 to the positive output terminal PB.

[0032] With reference to [Fig. 4], the control device 104 is designed to control the interconnection circuits II, 12 to alternate each of them between the first and second configurations. This control is phase-shifted, meaning that the alternation in time between the two configurations is offset from one interconnection circuit II, 12 to the other. Thus, there are time intervals during which one of the interconnection circuits II, 12 is in the first configuration, while another of the interconnection circuits II, 12 is in the second configuration. This reduces current ripple at the output of the input voltage source SA and in the output capacitor CS.

[0033] For example, for each interconnection circuit II, 12, each alternation between the two configurations extends over a period PI, P2, the latter having the same duration P. During each period PI, P2, the interconnection circuit II, 12 under consideration is in the first configuration, then in the second configuration, according to a duty cycle, that is to say, the duration of each configuration in the period PI, P2. In the illustrated example, the duty cycle is 0.5. The configuration alternation is thus carried out at a frequency F equal to the inverse of the duration of the period P.

[0034] The control device 104 is for example designed, in order to control the output voltage VB, to keep the duty cycle constant but to modify the frequency F. The latter is preferably kept above the resonance frequency Fl, F2 of each of the branches Brl, Br2.

[0035] Thus, in the case of two interconnection circuits II, 12, as in the illustrated example, the periods PI, P2 are preferably offset by 180°, that is to say by half the duration of period P: P / 2.

[0036] With reference to [Fig.5], in the case of three interconnection circuits, the periods PI, P2, P3 are preferably offset by 120°, i.e. by one third of the duration of period P: P / 3.

[0037] Generally, in the case of N interconnection circuits, the periods PI...PN are preferably offset by 360° / N, that is, by the duration of period P divided by N.

[0038] In conclusion, it is clear that a DC-DC converter such as the one described above makes it possible to reduce current oscillations.

[0039] It should also be noted that the invention is not limited to the embodiments described above. It will indeed be apparent to those skilled in the art that various modifications can be made to the embodiments described above, in light of the information just disclosed to them.

[0040] In the detailed presentation of the invention given above, the terms used shall not be interpreted as limiting the invention to the embodiments set forth in this description, but shall be interpreted as including all equivalents which can be foreseen by a person skilled in the art by applying their general knowledge to the implementation of the teaching which has just been disclosed to them.

Claims

Demands

1. DC-DC converter (102) comprising: - a positive input terminal (PA) and a negative input terminal (NA); - a positive output terminal (PB) and a negative output terminal (NB); - several branches (Brl, Br2) each comprising a capacitance (Cl, C2);- several interconnection circuits (II, 12) respectively associated with the branches (Brl, Br2) and each designed to alternately: • connect the associated branch (Brl, Br2) between the input terminals (PA, NA) to charge the capacitance (Cl, C2) from the positive input terminal (PA) so that the capacitance (Cl, C2) has a voltage (VC1, VC2), and • connect, between the output terminals (PB, NB), the branch (Brl, Br2) associated with the continuation of the input terminals (PA, NA) so that the voltage of the capacitance (VC1, VC2) is added to a DC input voltage (VA) present between the input terminals (PA, NA), to discharge the capacitance (Cl, C2) to the positive output terminal (PB); and - a control device (104) designed to control the interconnection circuits (II, 12) in a phase-shifted manner.

2. DC-DC converter (102) according to claim 1, wherein each branch (Brl, Br2) has an inductance (Ll, L2) in series with the capacitance (Cl, C2) of the branch (Brl, Br2) considered.

3. DC-DC converter (102) according to claim 1 or 2, wherein, for each interconnection circuit (II, 12), each alternation between the two configurations is carried out at a frequency and according to a duty cycle, and wherein the control device (104) is designed, in order to control a DC output voltage (VB) present between the output terminals (PB, NB), to keep the duty cycle constant but to change the frequency.

4. DC-DC converter (102) according to claims 2 and 3 taken together, wherein the control device (104) is designed to maintain the alternating frequency above a resonance frequency of each of the branches (Brl, Br2).

5. DC-DC converter (102) according to any one of claims 1 to 4, wherein each interconnection circuit (II, 12) comprises two controllable switches (Q1A, Q1B, Q2a, Q2b) connected to each other at a midpoint (M1, M2) and together between the input terminals (PA, NA) and two other switches (D1A, D1B, D2A, D2B) connected to each other at a midpoint (M'1, M'2) and together between the positive terminals (PA, PB), and wherein the branch (Brl, Br2) is connected between the midpoints (M1, M'1, M2, M'2).

6. DC-DC converter (102) according to claim 5, wherein the other switches are diodes (D1A, D1B, D2A, D2B) conducting towards the positive output terminal (PB).

7. DC-DC converter (102) according to any one of claims 1 to 6, wherein the branches (Brl, Br2) and the interconnection circuits (II, 12) are two, three, or four in number.

8. DC-DC converter (102) according to any one of claims 1 to 7, wherein, for each interconnection circuit (II, 12), each alternation between the two configurations extends over a period (PI, P2; PI, P2, P3), the latter having the same duration (P), and wherein the periods (PI, P2; PI, P2, P3) are offset by the duration of period (P) divided by N, N being the number of branches (Brl, Br2) and interconnection circuits (II, 12).

9. Mobility device comprising a DC-DC converter (100) according to any one of claims 1 to 8.

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