POWER SUPPLY SYSTEM INCLUDING A FUEL CELL

Abstract

The invention relates to an electrical power supply system (100), in particular configured to be mounted in a vehicle, comprising: a fuel cell (110); a battery (112), in particular configured to power said vehicle; an interleaved DCDC voltage converter (114) configured to power said battery (112) from said fuel cell (110); a compressor (116) configured to deliver a compressed oxidizing gas to said fuel cell (110); an inverter (118) configured to power said compressor (116); said interleaved DCDC voltage converter (114) comprising a plurality of parallel branches, called "one-way branches" (114m), each comprising a one-way boost converter (50) configured to power said battery (112) from the fuel cell (110);and at least one parallel branch, called the "bidirectional branch" (114b), comprising a bidirectional boost converter (60) and a diode (70) whose anode is connected to the fuel cell (110) and whose cathode is connected to a first terminal (61) of the bidirectional converter (60). Figure 2;

Description

Title of the invention: ELECTRICAL POWER SYSTEM COMPRISING A FUEL CELL

[0001] The invention relates to an electrical power supply system comprising a fuel cell, in particular configured to be installed in a vehicle. The invention further comprises a method for supplying electrical power to electrical equipment using the system according to the invention.

[0002] An acceleration in the development of electrical power systems comprising a fuel cell is expected, particularly for heavy mobility, due to their absence of greenhouse gas emissions. However, a barrier to their development lies in their complexity of implementation, particularly as an on-board system, for example in a vehicle.

[0003] An electrical power supply system is known comprising a fuel cell embedded in a vehicle, as illustrated in [Fig.l]. In particular, the electrical power supply system 1 delivers a voltage of 100kW to a motor M driving the vehicle. The electrical power supply system 1 comprises a fuel cell 2 which produces electrical energy. The fuel cell 2 typically operates at a power of approximately 110kW, with a voltage of 300V and a current of 360A. The voltage delivered by the fuel cell 2 is not high enough to directly power a first battery 3, which has a voltage of 800V at its terminals for example. The electrical power supply system 1 therefore comprises a monodirectional DCDC step-up converter 4 of 110kW, delivering a current of approximately 125A to the first battery 3 at a voltage of approximately 800V. The first battery 3 powers the motor M which drives the vehicle.A first inverter 5 converts the direct voltage delivered by the first battery 3 into an alternating voltage enabling the motor M to be driven. In particular, the motor M is three-phase and has a power of 100 kW. In addition to driving the vehicle, the first battery 3 can provide the electrical power supply to components of the electrical power system 1 and to auxiliary components of the vehicle. Thus, the electrical power system 1 further comprises a compressor 6 which delivers an oxidizing gas, such as air or oxygen from the air, to the fuel cell. The compressor 6 also draws its energy from the first battery 3 thanks to a second inverter 7 which converts the direct voltage delivered by the first battery into an alternating voltage driving the compressor 6 to be driven, via a motor (not shown). The compressor 6 has a power of 10 kW in particular.The second inverter 7 has for example a power of 10kW, and operates in particular at a voltage of 800V and a . current of 12.5A. The power supply system 1 may comprise a DCDC converter 8 converting the high voltage of the first battery 3 into a low or medium voltage, for example 12V, for a second battery 9. For example, the DCDC converter 8 operates at 2.4kW, and in particular receives a current of 3A from the first battery 3 and delivers a current of 21 OA to the second battery 9. The second battery 9 delivers its output voltage to a distribution box 10. This distributes the energy to the auxiliary components of the vehicle.

[0004] By being connected directly to the first battery 3, the second inverter 7 must withstand the voltage of 800V delivered by the first battery 3. The components of the second inverter 7, in particular its switches, must withstand such a voltage level, which makes the second inverter 7 heavier and more expensive. However, when starting the electrical power system, the compressor 6 must be able to receive its electrical power supply independently of the fuel cell 2, because the compressor 6 serves to initiate the production of energy by the fuel cell 2 by delivering the oxidizing gas to it. It is therefore also essential that the compressor 6 can be powered by the first battery at least during the start-up phase of the electrical power system.

[0005] An electrical power supply system comprising a fuel cell is therefore sought which allows the compressor to be powered less expensively and independently of the fuel cell at least during a start-up phase of the electrical power supply system.

[0006] To this end, the invention proposes an electrical power supply system, in particular configured to be installed in a vehicle, comprising: - a fuel cell; - a battery, in particular configured to drive said vehicle; - an interleaved DCDC voltage converter configured to power said battery from said fuel cell; - a compressor configured to deliver a compressed oxidizing gas to said fuel cell; - an inverter configured to power said compressor; said interleaved DCDC voltage converter comprising a plurality of parallel branches, called “monodirectional branches”, each comprising a monodirectional boost converter configured to power said battery from the fuel cell; and at least one parallel branch, called “bidirectional branch”, comprising a bidirectional boost converter and a diode whose anode is connected to the fuel cell and whose cathode is connected to a first terminal of the bidirectional converter;

[0007] said inverter being further connected between the diode and the first terminal of the bidirectional boost converter so as to receive a current from said fuel cell or from said battery for powering said compressor.

[0008] Thus, by connecting the inverter powering the compressor between the interleaved DCDC converter and the fuel cell, the voltage across the inverter is equal to the voltage across the fuel cell, except for the diode voltage. Since the voltage of the fuel cell is lower than that across the battery, the inverter can then operate at a lower voltage than in the prior art illustrated in [Fig.l], for example at a voltage between 300 and 400V. This reduces the weight and cost of the inverter compared to the power supply system 1 of the prior art. Furthermore, by providing at least one bidirectional branch in the interleaved DCDC converter, the inverter can receive a current from the battery, the diode making it possible to avoid a loopback of the current to the fuel cell.This makes it possible to power the compressor from the battery via the inverter, independently of the fuel cell, in particular at least during a start-up phase of the power supply system. Furthermore, during nominal operation of the power supply system, the current supplying the battery from the fuel cell flows in particular via the one-way branches, the two-way branch then also being able to contribute to the power supply of the battery.

[0009] According to one embodiment, the interleaved DCDC voltage converter comprises between 10 and 30% of bidirectional branches.

[0010] According to one embodiment, the first terminal of the bidirectional converter is configured to be connected to an auxiliary component, for powering said component when said power supply system is started.

[0011] According to one embodiment, the monodirectional and bidirectional converters comprise switches, said switches being configured to be controlled with the same duty cycle.

[0012] According to one embodiment, the monodirectional and bidirectional converters comprise switches, the switches of the monodirectional converters being configured to be controlled with a first duty cycle, and the switches of the bidirectional converter being configured to be controlled with a second duty cycle.

[0013] The invention further relates to a method for supplying electrical power to electrical equipment, said electrical equipment being in particular intended to drive a vehicle, comprising the use of an electrical power supply system according to the invention.

[0014] According to one embodiment, a start-up of the electrical power supply system comprises: • the delivery to the inverter of a current from the battery via the bidirectional converter; • controlling the inverter to power said compressor so as to initiate the production of electrical energy by said fuel cell; • when the voltage of said fuel cell becomes greater than the sum of the voltage at the first terminal of the bidirectional converter and the threshold voltage of the diode, the diode is switched on so as to deliver to the inverter a current from said fuel cell for supplying the compressor.

[0015] According to a variant, the method comprises after starting the electrical power supply system: • controlling the electrical power supply system so that the current delivered by the fuel cell in the bidirectional branch becomes greater than a threshold; • when said current delivered by the fuel cell in the bidirectional branch is greater than said threshold, the compressor is powered only from at least a first part of the current delivered by the fuel cell in the bidirectional branch.

[0016] According to a variant, the method further comprises, when said current delivered by the fuel cell is greater than said threshold, supplying the battery via the bidirectional converter with at least a second part of the current delivered by the fuel cell in the bidirectional branch.

[0017] According to a variant, the starting of the electrical power supply system comprises, in parallel with the delivery to the inverter of a current from the battery via the bidirectional converter, the delivery of a current from the battery via the bidirectional converter to an auxiliary component of the electrical equipment connected to the first terminal of the bidirectional converter.

[0018] According to one embodiment, the monodirectional and bidirectional converters comprising switches configured to be respectively controlled with a first and a second duty cycle, the method comprises supercharging the fuel cell of the electrical power supply system, said supercharging comprising: • when the diode is in a conducting state, controlling the bidirectional converter so that the voltage at the first terminal of the bidirectional converter increases until the voltage across the diode is lower than the threshold voltage of the diode; • the inverter receiving current only from the battery; • inverter control to increase compressor flow.

[0019] Other features and advantages of the present invention will become more apparent from reading the following description in relation to the following appended figures:

[0020] [Fig.l]: [Fig.l], already described, illustrates an example of an electrical power supply system according to the prior art;

[0021] [Fig.2]: [Fig.2] illustrates an example of an electrical power supply system according to the invention;

[0022] [Fig.3]: [Fig.3] represents the power supply system of [Fig.2] associated with other electrical components.

[0023] [Fig. 2] represents an example of an electrical power supply system 100 according to the invention. The electrical power supply system 100 is notably configured to be installed in a vehicle, for example a land motor vehicle such as a heavy goods vehicle, or an aircraft or other vehicle.

[0024] The electrical power system 100 comprises a fuel cell 110. For example, the fuel cell 110 comprises a plurality of cells. The fuel cell 110 can operate at a power of 110kW and deliver a voltage of approximately 300V for a current of approximately 360A. The electrical power system 100 further comprises a battery 112, which is in particular configured to power a motor driving the vehicle. The battery 112 is in particular a high-voltage battery delivering, for example, a voltage of approximately 800V. The electrical power system 100 further comprises an interleaved DCDC converter 114, which operates, for example, at a power of 100kW. The DCDC voltage converter 114 supplies the battery 112 from the fuel cell 110. For this purpose, the interleaved DCDC converter 114 delivers in particular to the battery 112 a voltage of 800V and a current of 125A.

[0025] The electrical power supply system 100 comprises a compressor 116 which delivers a compressed oxidizing gas to said fuel cell 110. The oxidizing gas comprises, for example, oxygen. In particular, in a manner known per se, the fuel cell 110 also receives a fuel such as hydrogen, and produces electricity from the oxidizing gas and the fuel. The fuel cell 110 is, for example, a hydrogen fuel cell with a proton exchange membrane. It operates in particular at a power of 100 kW, or even greater than 100 kW, for example 100 kW. An inverter 118 supplies the compressor 116. In particular, the inverter 118 delivers an alternating voltage to a motor 117 which drives the compressor 116.

[0026] The interleaved DCDC voltage converter 114 comprises several parallel branches 114m, 114b. The parallel branches 114m, 114b are in particular configured to convert a voltage between input terminals E0, E1, E2 and output terminals SI, S2 of the interleaved DCDC voltage converter 114. The interleaved DCDC converter 114 comprises branches 114m, called “monodirectional branches”, which each comprise a monodirectional boost converter 50 which supplies the battery 112 from the fuel cell 110. At least one of the parallel branches forms a branch 114b called “bidirectional branch”. The bidirectional branch 114b comprises a bidirectional boost converter 60 and a diode 70 whose anode is connected to the fuel cell 110 and the cathode to a first terminal 61 of the bidirectional converter 60.

[0027] The inverter 118 is connected between the diode 70 and the first terminal 61 of the bidirectional boost converter 60 so as to receive a current from the fuel cell 110 or from the battery 112 for powering the compressor 116. Thus, the voltage VL at the terminals of the fuel cell 110 is in particular equal to the sum of the voltage VD at the terminals of the diode 70 and the voltage VOND at the terminals of the inverter 118. The inverter 118 can therefore operate at a lower voltage than in the prior art illustrated in [Fig.l], for example between 300 and 400V. This reduces the weight and cost of the inverter 118 compared to the electrical power supply system 1 of the prior art. In particular, the voltage VOND across the inverter 118 is equal to the voltage between the first terminal 61 of the bidirectional converter 60 and a common terminal COM of the bidirectional converter 60.

[0028] Furthermore, due to its assembly, the diode 70 makes it possible to make the power supply of the compressor 116 dependent or independent of the fuel cell 110. Thus, for example, during a start-up phase of the power supply system 100, the voltage VL at the terminals of the fuel cell 110 being initially zero, the diode 70 is blocked. The bidirectional converter 60 of the bidirectional branch 114b of the DCDC converter 114 can then deliver to the inverter 118 a current from the battery 112 to power the compressor 116. The diode 70 only becomes conductive when the voltage VL at the terminals of the fuel cell 110 is sufficiently high so that the voltage VD at the terminals of the diode 70 becomes greater than its threshold voltage.Thus, the compressor 116 can then be powered by the fuel cell 110, in particular in a nominal operation of the electrical power supply system 100, in particular after the start-up phase of the electrical power supply system 100. By virtue of its assembly, the diode 70 only allows the circulation of a current from the fuel cell 110 to the bidirectional converter 60 or to the inverter 118; and thus prevents the looping back of a current in the fuel cell 110.

[0029] One or more auxiliary components 115 may be connected to the first terminal 61 of the bidirectional converter 60, in particular via an input terminal E2 of the interleaved DCDC converter 114. The auxiliary components 115 may be components of the vehicle comprising the electrical power supply system 100, which are preferably powered up before the supply of electrical energy by the fuel cell 110.

[0030] The proportion of bidirectional branches 114b relative to the monodirectional branches 114m is notably determined by the power required by the com presser 116 in the start-up phase or a boost phase of the power supply system 100. The proportion of bidirectional branches 114b may also be a function of the power required by the auxiliary components 115. For example, the interleaved DCDC voltage converter 114 comprises between 10 and 30% of bidirectional branches 114b.

[0031] In particular, in each monodirectional branch 114m, a first input terminal 51 of the monodirectional converter 50 is connected to a positive terminal of the fuel cell 110; and a second output terminal 52 is connected to a positive terminal of the battery 112. In particular, respective negative terminals of the fuel cell 110 and of the battery 112 are connected to a common terminal COM of the monodirectional converter 50. In particular, each monodirectional converter 50 forms a boost converter configured to deliver to the battery 112 a higher voltage VH from the voltage VL coming from the fuel cell 110. For this purpose, the monodirectional converter 50 may comprise an inductance Lm connected between the first terminal 51 of the monodirectional converter 50 and the midpoint of an arm.The arm comprises in particular a switch Tm connected between the midpoint and the common terminal COM; and a diode Dm whose anode is connected to the midpoint of the arm and the cathode to the second output terminal 52. Capacitors Cml, Cm2 can be respectively connected between the first terminal 51 of the unidirectional converter 50 and the common terminal COM, and between the second terminal 52 and the common terminal COM.

[0032] In particular, in the bidirectional branch 114b, the first input terminal 61 of the bidirectional converter 60 is connected to the cathode of the diode 70; and the anode of the diode 70 is connected to the positive terminal of the fuel cell 110. Furthermore, the first terminal 61 of the bidirectional converter 60 is in particular connected to a positive terminal of the inverter 118. A second output terminal 62 of the bidirectional converter 60 can be connected to the positive terminal of the battery 112. In particular, the respective negative terminals of the fuel cell 110 and the battery 112 are connected to the common terminal COM of the bidirectional converter 60.

[0033] In particular, the bidirectional converter 60 forms a boost converter configured to deliver to the battery 112 a current from the fuel cell 110, the battery 112 having a voltage VH higher than the voltage VL of the fuel cell 110. Due to its bidirectional nature, the bidirectional converter 60 can further deliver to the inverter 118 a current from the battery 112, the battery 112 having a voltage VH higher than the voltage VOND of the inverter 118.

[0034] The bidirectional converter 60 may comprise an inductor Lb connected between the first terminal 61 of the bidirectional converter 60 and the midpoint of a arm. The arm comprises in particular a first switch Tbl connected between the midpoint and the common terminal COM; and a second switch Tb2 connected between the midpoint of the arm and the second output terminal 62 of the bidirectional converter 60. In a manner known per se, the switches Tbl, Tb2 may be in parallel with a respective diode configured to allow current flow during opening phases of the switches Tbl, Tb2. Capacitors Cbl, Cb2 may be respectively connected between the first terminal 61 of the bidirectional converter 60 and the common terminal COM, and between the second terminal 62 and the common terminal COM. The monodirectional converters 50 and bidirectional converter 60 may have configurations other than those illustrated in the figures.

[0035] A start-up phase of the electrical power supply system 100 will now be described in the following.

[0036] The power supply system 100 may have been previously shut down, such that the voltage across the fuel cell 110 is zero. However, the battery 112 is preferably at least partially charged.

[0037] The start-up of the power supply system 100 comprises the delivery to the inverter 118 of a current from the battery 112 via the bidirectional converter 60. The bidirectional converter 60 converts in particular the voltage VH of the battery 112 into a lower voltage VOND delivered to the inverter 118. For this purpose, the switches Tbl, Tb2 of the bidirectional converter 60 can be controlled with a duty cycle. In particular, the bidirectional converter 60 is regulated to deliver to the inverter 118 a voltage of value between 300 and 400V. In particular, the diode 70 of the bidirectional branch 114b is then in a blocking state, thus preventing the flow of a current from or to the fuel cell 110.

[0038] The inverter 118 is then controlled to power the compressor 116, in particular via the motor 117. The compressor 116 initiates the production of electrical energy by the fuel cell 110, in particular by supplying the fuel cell 110 with oxidizing gas. Thus, the compressor 116 is powered independently of the fuel cell 110 and can then start the fuel cell 110.

[0039] The voltage VL of the fuel cell 110 increases until it is greater than the sum of the voltage VOND at the first terminal 61 of the bidirectional converter 60 and the threshold voltage of the diode 70. The diode 70 then enters a conducting state. A current from the fuel cell 110 can then be delivered to the inverter 118 to power the compressor 116, in particular via the motor 117. Thus, when the fuel cell 110 has sufficient voltage at its terminals, it can deliver a current to the inverter 118 so as to at least partially power the compressor 116.

[0040] During the start-up of the power supply system 100, the monodirectional converters 50 can operate in parallel with the bidirectional converter 60, in particular to supply the battery 112 with a current from the fuel cell 110.

[0041] At the end of this start-up phase, the electrical power supply system 100 can be controlled so that the fuel cell 110 delivers a current, at least a portion of which supplies the inverter 118 via the bidirectional branch 114b. The current delivered by the fuel cell 110 can supply only the bidirectional branch 114b in the case where the monodirectional converters 50 are all inactive. Alternatively, the current delivered by the fuel cell 110 can be distributed between the bidirectional branch 114b and the monodirectional branches 114m, controlled to ensure an electrical conversion to the battery 112. The electrical power supply system 100 can be controlled so that the fuel cell 110 delivers a total current such that the portion of current supplying the bidirectional branch 114b is higher than a current threshold.In particular, the interleaved DCDC converter 114 determines the current extracted from the fuel cell 110. In particular, the switches of the monodirectional boost converters 50 and / or the bidirectional boost converter 60 are controlled for this purpose. The current determined by the interleaved DCDC converter 114 can in particular only be delivered on the condition that the supply of oxidizing gas and fuel to the cell is sufficient, or that the operating state of the fuel cell 110 allows it. For example, the flow rate of oxidizing gas delivered by the compressor 116 and / or that of fuel, in particular hydrogen, is then adjusted. When the current delivered to the bidirectional branch 114b by the fuel cell 110 is greater than the current threshold, the supply of the compressor 116 is carried out solely from the fuel cell 110.In other words, the current delivered by the fuel cell 110 satisfies the current demands of the inverter 118, so that the current from the battery 112 to the inverter 118 is cancelled. The current threshold is preferably determined as a function of a nominal operating current of the inverter 118. Thus, after the start-up phase, the compressor 116 can be powered solely by the fuel cell 110 once the threshold is reached.

[0042] Beyond this threshold, the bidirectional converter 60 no longer has to supply the inverter 118 from the battery 112. The bidirectional converter 60 can then convert, in parallel with the monodirectional converters 50, energy delivered by the fuel cell 110 to the battery 112. The bidirectional converter 60 can therefore support the monodirectional converters 50 during nominal operation of the electrical power supply system 100.

[0043] When an auxiliary component 115 is connected to the first terminal 61 of the bidirectional converter 60, the start-up phase may comprise the delivery to the auxiliary component 115 of a current from the battery 112 via the bidirectional converter 60. Preferably, the current threshold is then determined to allow sufficient current in the inverter 118 and the auxiliary component 115.

[0044] The switches Tm, Tbl, Tb2 of the monodirectional converters 50 and bidirectional converters 60 may be controlled with the same duty cycle, the first switch Tbl of the bidirectional converter 60 being controlled in phase with the switches Tm of the monodirectional converters, the second switch Tb2 being controlled in phase opposition. The electrical power supply system 100 may then comprise a single control unit delivering the same duty cycle to all the converters 50, 60 of the interleaved DCDC converter 100.

[0045] Alternatively, the switches Tm, Tbl, Tb2 of the monodirectional converters 50 and bidirectional converters 60 may be controlled with different duty cycles. Thus, the switches Tm of the monodirectional converters 50 may be configured to be controlled with a first duty cycle, the switches Tbl, Tb2 of the bidirectional converters 60 being configured to be controlled with a second duty cycle. Such differentiated control of the duty cycles does not prevent the first and second duty cycles from having identical values, in particular in nominal operation of the electrical power system. In such a configuration, a boosting phase of the fuel cell 110 may be implemented in the electrical power system 100.

[0046] The supercharging of the fuel cell 110 comprises an increase in the flow rate of oxidizing gas to increase the electrical energy delivered by the fuel cell 110. In particular, the power supply system 100 is initially in nominal operation, in which the diode 70 of the bidirectional branch 114b is in an on state. The bidirectional converter 60 is then controlled so that the voltage VOND at the first terminal 61 of the bidirectional converter 60 increases. The voltage VOND at the first terminal 61, i.e. the voltage VOND of the inverter 118, increases until the voltage VD across the diode 70 is lower than the threshold voltage of the diode 70. The diode 70 then enters a blocking state. The inverter 118 receives current only from the battery 112. The inverter 118 can then be controlled to increase the flow rate of the compressor 116.

[0047] In nominal operation of the power supply system 100, the branches 114m, 114b of the interleaved DCDC converter 114 do not necessarily all operate in parallel. Some branches 114m, 114b may be inactive depending on the optimal efficiency of the interleaved DCDC converter 114 for a given torque of fuel cell voltage VL and battery voltage VH.

[0048] The inductances Lm, Lb of the monodirectional converters 114m and bidirectional converters 114b may be coupled together to improve the integration of the power supply system 100. Furthermore, the inductances Lm, Lb may be configured so that their conduction mode is continuous at the operating points of the power supply system 100.

[0049] The electrical power supply system 100 may be associated with other electrical components for a power supply of a vehicle, for example as illustrated in [Fig. 3], in which the motor 117 actuating the compressor 116 is not shown. The battery 112 is in particular connected to an inverter 120 controlling the actuation of a motor M which drives the vehicle. The battery 112 may also be connected to a DCDC converter 122 converting the high voltage of the battery 112 into a low or medium voltage, for example 12V. This low or medium voltage is delivered to a battery 124, which in turn supplies a distribution box 126 distributing the electrical energy to auxiliary components of the vehicle. Thanks to the interleaved DCDC converter 14, a power PI can flow from the battery 112 to the inverter 118, in particular in a start-up or boosting phase of the electrical power supply system 100.The power PI is for example 100kW. Furthermore, in particular in a nominal operation of the electrical power supply system 100, the interleaved DCDC converter 114 can deliver a power P2 from the fuel cell 110 to the battery 112. The power P2 is for example 100kW.

[0050] In the interleaved DCDC voltage converter 114, both the monodirectional branches 114m and the bidirectional branch 114b can be used to power the battery 112. This makes it possible to optimize the sizing of the voltage converter 114 compared to a converter in which the branches powering the inverter from the battery would only be dedicated to this function.

[0051] In particular, the voltage VOND of the inverter 118, the voltage VL of the fuel cell, the voltage VH of the battery are referenced relative to the same common terminal COM. In other words, said terminal COM is common to the inverter 118, the fuel cell 110, the battery 112 and in particular the monodirectional converters 50, and forms their low level potential.

[0052] Each monodirectional converter 50 and / or each bidirectional converter 60 may comprise a current sensor 130, in particular at its first terminal 51, 61.

[0053] The interleaved DCDC converter 114 is easily modular, the number of unidirectional branches 114m and the number of bidirectional branches 114b being able to be adapted according to the power requirements. In addition, by being located in the bidirectional branch 114b, the diode 70 only sees the current flowing in this branch 114b and not the current delivered at the output of the fuel cell 110. The current flowing in the bidirectional branch 114b being lower than the current delivered at the output of the fuel cell 110, the losses in the diode 70 are lower than if it were positioned at the output of the fuel cell 110. For example, the current flowing in the diode 70 is between 10 and 30% of the current delivered at the output of the fuel cell 110. In particular, the current flowing in the diode 70 is between 10 and 50A.

[0054] The bidirectional branch 114b and the monodirectional branches 114m are integrated into the interleaved DCDC converter 114. This forms in particular a single electrical equipment contained in a box having the terminals E0, El, E3, SI, S2 as interfaces. Thus, when assembling the electrical power supply system 100, the number of different components to be connected is limited.

Claims

Claims

1. Electrical power supply system (100), in particular configured to be embedded in a vehicle, comprising: • a fuel cell (110); • a battery (112), in particular configured to drive said vehicle; • an interleaved DCDC voltage converter (114) configured to power said battery (112) from said fuel cell (110); • a compressor (116) configured to deliver a compressed oxidizing gas to said fuel cell (110); • an inverter (118) configured to power said compressor (116); said interleaved DCDC voltage converter (114) comprising a plurality of parallel branches, called “monodirectional branches” (114m), each comprising a monodirectional boost converter (50) configured to power said battery (112) from the fuel cell (110);and at least one parallel branch, called a "bidirectional branch" (114b), comprising a bidirectional boost converter (60) and a diode (70) whose anode is connected to the fuel cell (110) and whose cathode is connected to a first terminal (61) of the bidirectional converter (60); said inverter (118) being further connected between the diode (70) and the first terminal (61) of the bidirectional boost converter (60) so as to receive a current from said fuel cell (110) or from said battery (112) for powering said compressor (116).;

2. The power supply system (100) of claim 1, wherein the interleaved DCDC voltage converter (114) comprises between 10 and 30% bidirectional branches (114b).

3. Power supply system (100) according to claim 1 or 2, wherein the first terminal (61) of the bidirectional converter (60) is configured to be connected to an auxiliary component (115), for powering said component upon start-up of said power supply system (100).

4. Power supply system (100) according to one of the claims previous, in which the monodirectional (50) and bidirectional (60) converters comprise switches (Tm, Tbl, Tb2), said switches (Tm, Tbl, Tb2) being configured to be controlled with the same duty cycle.

5. Power supply system (100) according to one of claims 1 to 3, wherein the monodirectional (50) and bidirectional (60) converters comprise switches (Tm, Tbl, Tb2), the switches (Tm) of the monodirectional converters (50) being configured to be controlled with a first duty cycle, and the switches (Tbl, Tb2) of the bidirectional converter (60) being configured to be controlled with a second duty cycle.

6. Method for supplying electrical power to electrical equipment, said electrical equipment being intended in particular to drive a vehicle, comprising the use of an electrical power supply system (100) according to one of the preceding claims.

7. Method for powering electrical equipment according to the preceding claim, wherein starting the electrical power supply system (100) comprises: • delivering to the inverter (118) a current from the battery (112) via the bidirectional converter (60); • controlling the inverter (118) to power said compressor (116) so as to initiate the production of electrical energy by said fuel cell (110); • when the voltage (VL) of said fuel cell (110) becomes greater than the sum of the voltage (VOND) at the first terminal (61) of the bidirectional converter (60) and the threshold voltage of the diode (70), turning on the diode (70) so as to deliver to the inverter (118) a current from said fuel cell (110) for powering the compressor (116).

8. Method according to the preceding claim, comprising after starting the electrical power supply system (100): • controlling the electrical power supply system (100) so that the current delivered by the fuel cell (110) in the bidirectional branch (114b) becomes greater than a threshold; • when said current delivered by the fuel cell (110) in the bidirectional branch (114b) is greater than said threshold, the power supply of the compressor (116) only from at least a first part of the current delivered by the fuel cell (110) in the bidirectional branch (114b).

9. Method according to the preceding claim, further comprising: when said current delivered by the fuel cell (110) in the bidirectional branch (114b) is greater than said threshold, supplying the battery (112) via the bidirectional converter (60) with at least a second part of the current delivered by the fuel cell (110) in the bidirectional branch (114b).

10. Method according to one of claims 7 to 9, wherein the starting of the electrical power system (100) comprises, in parallel with the delivery to the inverter (118) of a current from the battery (112) via the bidirectional converter (60), the delivery of a current from the battery (112) via the bidirectional converter (60) to an auxiliary component (115) of the electrical equipment connected to the first terminal (61) of the bidirectional converter (60).

11. Method according to one of claims 6 to 10, the monodirectional (50) and bidirectional (60) converters comprising switches (Tm, Tbl, Tb2) configured to be respectively controlled with a first and a second duty cycle, the method comprising a supercharging of the fuel cell (110) of the electrical power supply system (100), said supercharging comprising: • when the diode (70) is in a conducting state, the control of the bidirectional converter (60) so that the voltage (VOND) at the first terminal (61) of the bidirectional converter (60) increases until the voltage (VD) at the terminals of the diode (70) is lower than the threshold voltage of the diode (70); • the reception by the inverter (118) of a current only from the battery (112); • the control of the inverter (118) so as to increase the flow rate of the compressor (116).

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