DC-DC CONVERTER

Abstract

The DC-DC converter (102) comprises: - positive and negative input terminals (PA, NA); - positive and negative output terminals (PB, NB); - at least one set (E1, E2) of a capacitor (C1, C2) and a first inductor (L1, L2); - for each set (E1, E2), an interconnection circuit (I1, I2) comprising: a first upper switch (Q1A, Q2A) and a first lower switch (Q1B, Q2B), and an upstream switch (Q1C, Q2C) and a downstream switch (Q1D, Q2D), the capacitor (C1, C2) and the first inductor (L1, L2) of the set (E1, E2) being connected one after the other between the midpoints (M1, M2, M'1, M'2) of the switches.The upstream switch (Q1C, Q2C) and the downstream switch (Q1D, Q2D) are each bidirectional, and the DC-DC converter (102) further includes a control device (104) designed to regulate a DC output voltage (VB) between the output terminals (PB, NB) selectively above or below the DC input voltage (VA) by controlling each interconnection circuit (I1, I2). Figure for the abstract: 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, between the output terminals, the branch following the input terminals so that the capacitor voltage is added to a DC input voltage, to discharge the capacitor to 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, which makes it possible to regulate a DC output voltage present between the output terminals, only to a value greater than that of the DC input voltage.

[0005] 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

[0006] 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; - at least one set of a capacitor and a first inductance; - for each assembly, an interconnection circuit comprising: • a first upper switch and a first lower switch connected to each other the other at a first midpoint, the first upper switch being connected between the positive input terminal and the first midpoint and the first lower switch being connected between the first midpoint and the negative input terminal, and • an upstream switch and a downstream switch connected to each other at a second midpoint, the upstream switch being connected between the positive input terminal and the second midpoint and the downstream switch being connected between the second midpoint and the positive output terminal; the capacitor and the first inductor of the assembly being connected one after the other between the first midpoint and the second midpoint;the interconnection circuit being designed to take: • a first configuration, in which the lower switch and the first upstream switch are closed and the first upper switch and the downstream switch are open, to charge the capacitor from the positive input terminal, and • a second configuration, in which the first upper switch and the downstream switch are closed and the first lower switch and the upstream switch are open, to discharge the capacitor to the positive output terminal; characterized in that the upstream switch and the downstream switch are each bidirectional, and in that it further comprises a control device designed to regulate a DC output voltage between the output terminals selectively above or below the DC input voltage by controlling each interconnecting circuit to alternate between the first configuration and the second configuration.

[0007] Thanks to the invention, it is possible to regulate the DC output voltage to a level higher or lower than the DC input voltage.

[0008] The invention may further include one or more of the following optional features, according to any technically possible combination.

[0009] Optionally, the upstream switch and / or the downstream switch includes two transistors in series with a common source.

[0010] Optionally, the capacitor and the first inductor are also connected to each other at a third midpoint, the capacitor being connected between the second and third midpoints. Each assembly includes a second inductor. The interconnection circuit of each assembly further includes a second high switch and a second low switch connected to each other at a fourth midpoint, the second high switch being connected between the positive output terminal and the fourth midpoint, and the second low switch being connected between the first fourth midpoint and the negative output terminal. The capacitor and the second inductor of the assembly are connected to each other. following the other between the fourth midpoint and the second midpoint; the interconnection circuit being designed to take: - a third configuration, in which the lower switch and the first upstream switch are closed and the first upper switch and the downstream switch are open, to charge the capacitance from the positive output terminal; and - a fourth configuration, in which the first upper switch and the downstream switch are closed and the first lower switch and the upstream switch are open, to discharge the capacitance to the positive input terminal; and the control device is designed to control each interconnection circuit in order to regulate the DC input voltage selectively above or below the DC output voltage by controlling each interconnection circuit to alternate between the third and fourth configurations.

[0011] Optionally also, the DC-DC converter is with several assemblies and several associated interconnection circuits, and the control device is designed to control the interconnection circuits in a phase-shifted manner.

[0012] 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.

[0013] Optionally also, for each interconnection circuit, each alternation between the first and second configuration is carried out at a frequency and according to a duty cycle, and the control device is designed, in order to control the DC output voltage, to keep the duty cycle constant but to change the frequency.

[0014] Optionally also, the control device is designed to maintain the alternating frequency above a resonance frequency of the capacitor and the first inductor.

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

[0016] Optionally also, for each interconnection circuit, each alternation between the first and second 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 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: - Figure [1] is an electrical diagram of an electrical circuit comprising a DC-DC converter according to the invention, for converting a DC input voltage into a DC output voltage, - Figure [Fig. 2] illustrates a first configuration of a first interconnection circuit of the DC-DC converter of Figure [Fig. 1], when the DC output voltage is lower than the DC input voltage, - Figure 3 illustrates a second configuration of the first circuit of interconnection, when the DC output voltage is lower than the DC input voltage, - Figure 4 illustrates the first configuration of the first interconnection circuit, when the DC output voltage is greater than the DC input voltage. - Figure 5 illustrates the second configuration of the first circuit of interconnection, when the DC output voltage is greater than the DC input voltage, - [Fig. 6] is a chronogram illustrating an example of alternating configuration of the two interconnection circuits, - [Fig. 7] is a timing diagram illustrating an example of alternating configurations of three interconnecting circuits, and - Figure 8 is an electrical diagram of another DC-DC converter according to the invention, this time bidirectional. 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 at least one assembly El, E2 comprising a capacitor Cl, C2 and an inductor L1, L2 connected in series. This creates a resonance between the capacitor Cl, C2 and the inductor L1, L2, at a resonant frequency Fl, F2: Fl = 1 / VLICl and F2 = 1 / VL2C2. The inductor L1, L2 also limits the current flowing through the capacitor Cl, C2. For example, as in the illustrated example, the capacitor Cl, C2 and the first inductor L1, L2 are connected in series on a branch Br1, Br2.

[0026] Preferably, the capacitances Cl, C2 are of the same value, for example within 1%, as are the inductances L1, L2, which are of the same value, for example within 1%, from one set to another. For example, the values ​​of the capacitances Cl, C2 are between 10 nF and 100 pF. Again, for example, the values ​​of the inductances L1, L2 are between 100 nH and 100 pF.

[0027] The DC-DC converter 102 further comprises several interconnection circuits II, 12 respectively associated with the assemblies El, E2. Each of the interconnection circuits II, 12 is designed to alternatively connect the associated assembly El, E2 according to first and second configurations which will be detailed later.

[0028] 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. The controllable switch Q1A, Q2A is said to be high and is connected between the positive input terminal PA and the midpoint M1, M2. The controllable switch Q1B, Q2B is said to be low and is connected between the midpoint M1, M2 and the negative input terminal NA.

[0029] Again, for example, as in the illustrated example, each interconnection circuit II, 12 further comprises two switches Qlc, Q1d connected to each other at a midpoint M'1, M'2 and together between the positive terminals PA, PB. The controllable switch Qlc, Q2C is said to be upstream and is connected between the positive input terminal PA and the midpoint M'1, M'2. The controllable switch Q1D, Q2D is said to be downstream and is connected between the midpoint M'1, M'2 and the positive output terminal PB.

[0030] The assembly El, E2 is then connected between the midpoints M1, M'1 and M2, M'2, with the capacitor Cl, C2 and the inductor L1, L2 connected one after the other between these midpoints M1, M'1 and M2, M'2. In particular, when the capacitor Cl, C2 and the inductance L1, L2 are in series on the branch Br1, Br2, this means for example that this branch Br1, Br2 extends from the midpoint M1, M2 to the midpoint M'1, M'2, as in the illustrated example.

[0031] Each switch Q1A, Q1B, Q1C, Q2D, Q2A, Q2B, Q2C, Q2D preferably comprises at least one 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. (from the English "Gallium Nitride Field Effect Transistor" also designated by the acronym GaN FET).

[0032] The switches Qlc, QlDet, Q2C, and Q2D are bidirectional, meaning they can block current in both directions. To achieve this, each switch Qlc, QlDet, Q2C, and Q2D comprises, for example, two transistors Qlci, Qlc2, Q2ci, Q2C2, Q1di, Q1d2, Q2Di, and Q2d2 in series with a common source. Indeed, the transistors QlCi, Qlc2, Q2Ci, Q2C2, Q1di, Q1D2, Q2Di, and Q2d2 each have a freewheeling diode, as illustrated. By connecting them in pairs in series with a common source, the diodes are connected in opposition.

[0033] Thus, switch Qlc comprises a transistor QlCi and a transistor Q1C2 in series in that order from the positive input terminal PA to the midpoint M'1. Switch Q1D comprises a transistor QlDi and a transistor Q1D2 in series in that order from the midpoint M'1 to the positive output terminal PB. The same applies to switches Q2C and Q2D.

[0034] The DC-DC converter 102 then includes a control device 104 designed to regulate the DC output voltage VB selectively above or below the DC input voltage VA by controlling each interconnection circuit II, 12 to alternate between the first configuration and the second configuration.

[0035] For example, as in the illustrated example, the control device 104 is designed to control the various switches.

[0036] With reference to [Fig. 2], the interconnection circuit II is shown in the first configuration, when the output voltage VB is less than the voltage input VA. In this first configuration, the interconnect circuit II connects the entire El assembly, and in particular the Brl branch, between the input terminals PA and NA to charge the capacitor Cl from the positive input terminal PA so that the capacitor Cl has a voltage VC1. For example, as in the illustrated example, the lower switch Q1B and the upstream switch Qlc are closed, while the upper switch Q2b and the downstream switch Q1D are open. More precisely, for the upstream switch Qlc, at least transistor QlCi is closed, and for the downstream switch Q1D, at least switch Q1Di is open.

[0037] With reference to [Fig. 3], the interconnection circuit II is shown in the second configuration, again when the output voltage VB is less than the input voltage VA. In this second configuration, the interconnection circuit II connects the entire El assembly, in particular the Brl branch, following the input terminals PA and NA so that the voltage VC1 of the capacitor Cl is added to the input voltage VA. Furthermore, the input terminals PA and NA and the entire El assembly, in particular the Brl branch, are connected between the output terminals PB and NB to discharge the capacitor Cl to the positive output terminal PB. For example, as in the illustrated example, the lower switch Q1B and the upstream switch Qlc are open, while the upper switch Q2B and the downstream switch Q1D are closed. More specifically, for the upstream switch Qlc, at least transistor Qlc 2 is open and, for the downstream switch Q1d, at least switch Q1Di is closed.

[0038] With reference to [Fig.4], in the first configuration, when the output voltage VB is greater than the input voltage VA, for the upstream switch Qlc, at least transistor Qlc 1 is closed and, for the downstream switch Q1D, at least switch Q1D 2 is open.

[0039] With reference to [Fig.5], in the second configuration, when the output voltage VB is greater than the input voltage VA, or at least transistor Q1C2 is open and at least transistor Q1Di is closed.

[0040] The interconnection circuit 12 is designed to take the first and second configurations, similarly to the interconnection circuit II.

[0041] With reference to [Fig. 6], the control device 104 is designed to control the interconnection circuits II, 12 to alternate each of them between the first and second configurations, denoted respectively CONF1 and CONF2. This control is preferably phase-shifted, that is, the alternation in time between the first and second 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. Thus, this helps to reduce current ripple at the output of the input voltage source SA and in the output capacitor CS.

[0042] 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 period duration P.

[0043] The control device 104 is, for example, designed 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 sets El, E2.

[0044] 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.

[0045] With reference to [Fig.7], 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.

[0046] 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.

[0047] With reference to [Fig.8], in another embodiment, the DC-DC converter 102 can further be bidirectional, so as to transfer electrical power from the input terminals PA, NA to the output terminals PB, NP as described above, but also in the other direction.

[0048] For this purpose, each interconnection circuit II, 12 further comprises another upper switch Q' 1A, Q'2A and another lower switch Q' 1B, Q'2B connected to each other at a midpoint M'” 1, M'”2, the upper switch Q' 1A, Q'2A being connected between the positive output terminal PB and the midpoint M'”1, M'”2 and the lower switch Q' 1B, Q'2b being connected between the fourth midpoint M’”1, M’”2 and the negative output terminal NB.

[0049] The associated assembly El, E2 includes another inductance L'1, L'2, arranged so that the capacitance Cl, C2 and this inductance L'1, L'2 are connected one after the other between the midpoint M'"1, M'"2 and the midpoint M'1, M'2. For example, the inductance L'1, L'2 is connected between the midpoint M"1 and the midpoint M'"1.

[0050] Thus, when the switches Q' 1A, Q' 1B and Q'2A, Q'2B are open, the branch containing the inductance L' 1 is as non-existent and each interconnection circuit II, 12 is designed to take the first and second configurations described previously.

[0051] When switches Q1A, Q1B and Q2A, Q2B are open, the branch containing inductance L1 is as if non-existent and each interconnection circuit II, 12 is further designed to take third and fourth configurations, similar to the first and second configurations described previously, by exchanging switches Q1A, Q1B, Q2A, Q2B with switches Q'1A, Q'1B, Q'2A, Q'2B and inductance L1 with inductance L'1.

[0052] The control device 104 is further designed to control each interconnection circuit II, 12 in order to regulate the input DC voltage VA selectively above or below the output DC voltage VB by controlling each interconnection circuit II, 12 to alternate between the third configuration and the fourth configuration, in particular in a phase-shifted manner as described above.

[0053] In conclusion, it is clear that a DC-DC converter such as those described above makes it possible to regulate the output voltage to a level higher or lower than the input voltage and, in some embodiments, to reduce current oscillations.

[0054] 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.

[0055] 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

1. Claims 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); at least one set (El, E2) of a capacitance (Cl, C2) and a first inductance (Ll, L2); For each set (E1, E2), an interconnection circuit (II, 12) comprising: • a first upper switch (Q1a, Q2a) and a first lower switch (Q1b, Q2b) connected to each other at a first midpoint (M1, M2), the first upper switch (Q1a, Q2a) being connected between the positive input terminal (PA) and the first midpoint (M1, M2) and the first lower switch (Q1b, Q2b) being connected between the first midpoint (M1, M2) and the negative input terminal (NA), and • an upstream switch (Q1c, Q2C) and a downstream switch (Q1d, Q2d) connected to each other at a second midpoint (M'1, M'2), the upstream switch (Q1c, Q2C) being connected between the positive input terminal (PA) and the second midpoint (M'1, M'2) and the downstream switch (Q1d, Q2d) being connected between the second midpoint (M'1, M'2) and the positive output terminal (PB);the capacitance (Cl, C2) and the first inductance (Ll, L2) of the set (El, E2) being connected one after the other between the first midpoint (Ml, M2) and the second midpoint (M' 1, M'2); the interconnection circuit (II, 12) being designed to take: • a first configuration, in which the lower switch (QIb, Q2b) and the first upstream switch (Qlc, Q2C) are closed and the first upper switch (Q1A, Q2A) and the downstream switch (Q1D, Q2D) are open, to charge the capacitor (Cl, C2) from the positive input terminal (PA), and • a second configuration, in which the first upper switch (Q1A, Q2A) and the downstream switch (Q1d, Q2d) are closed and the first lower switch (Q1b, Q2b) and the upstream switch (Qlc, Q2C) are;

2.

3. open, to discharge the capacitance (Cl, C2) towards the positive output terminal (PB); characterized in that the upstream switch (Qlc, Q2C) and the downstream switch (Q1d, Q2d) are each bidirectional, and in that it further comprises a control device (104) designed to regulate a DC output voltage (VB) between the output terminals (PB, NB) selectively above or below a DC input voltage (VA) between the input terminals (PA, NA) by controlling each interconnection circuit (II, 12) to alternate between the first configuration and the second configuration. DC-DC converter (102) according to claim 1, wherein the upstream switch (Qlc, Q2C) and / or the downstream switch (Q1D, Q2d) comprises two transistors (Qlc i, Qlc 2, Q2c 1, Q2C 2) in series with common source. A DC-DC converter (102) according to claim 1 or 2, wherein the capacitor (C1, C2) and the first inductor (L1, L2) are connected to each other at a third midpoint (M'1, M'2), the capacitor (C1, C2) being connected between the second midpoint (M'1, M'2) and the third midpoint (M'1, M'2), wherein each set (E1, E2) comprises a second inductor (L'1, L'2), wherein the interconnection circuit (II, 12) of each set (E1, E2) further comprises a second high switch (Q'1A, Q'2A) and a second low switch (Q'1B, Q'2B) connected to each other at a fourth midpoint (M'1, M'2), the second high switch (Q'1A, Q'2A) being connected between the positive output terminal (PB) and the fourth midpoint (M”'1, M’”2) and the second bottom switch (Q’1B, Q’2B) being connected between the first fourth middle (M’”1, M’”2) and the negative output terminal (NB);the capacitor (Cl, C2) and the second inductor (L'1, L'2) of the assembly (El, E2) being connected one after the other between the fourth midpoint (M'”1, M'”2) and the second midpoint (M'1, M'2); the interconnection circuit (II, 12) being designed to take: • a third configuration, in which the lower switch (Q1B, Q2B) and the first upstream switch (Qlc, Q2C) are closed and the first upper switch (Q1A, Q2a) and the downstream switch (Q1D, Q2D) are open, to charge the capacitor (Cl, C2) from the positive output terminal (PB); and •; a fourth configuration, in which the first upper switch (Q1a, Q2a) and the lower switch (Q1D, Q2D) are closed and the first lower switch (Q1B, Q2B) and the upper switch (Qlc, Q2C) are open, to discharge the capacitance (Cl, C2) to the positive input terminal (PA); and in which the control device (104) is designed to control each interconnection circuit (II, 12) in order to regulate the DC input voltage (VA) selectively above or below the DC output voltage (VB) by controlling each interconnection circuit (II, 12) to alternate between the third and fourth configurations.

4. DC-DC converter (102) according to any one of claims 1 to 3, with several assemblies (El, E2) and several associated interconnection circuits (II, O2), wherein the control device (104) is designed to control the interconnection circuits (II, I2) in a phase-shifted manner.

5. DC-DC converter (102) according to claim 4, wherein, for each interconnection circuit (II, 12), each alternation between the first and second configuration is carried out at a frequency and according to a duty cycle, and wherein the control device (104) is designed, in order to control the DC output voltage (VB), to keep the duty cycle constant but to change the frequency.

6. DC-DC converter (102) according to claims 4 and 5 taken together, wherein the control device (104) is designed to maintain the alternating frequency above a resonance frequency of the capacitance (Cl, C2) and the first inductance (Ll, L2).

7. DC-DC converter (102) according to any one of claims 1 to 6, wherein the assemblies (El, E2) and the interconnection circuits (II, 12) are two, three, or four in number.

8. A DC-DC converter (102) according to any one of claims 1 to 7, wherein, for each interconnection circuit (II, 12), each half-cycle between the first and second configurations spans one 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 period duration 14 (P) divided by N, N being the number of 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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