Method for controlling bi-directional charger

Abstract

A method (120) for controlling a bi-directional charger (1) comprising a bi-directional AC-DC converter (130) connected to a bi-directional DC-DC converter (140) via a DC bus (150), said charger being connected both to a battery (110) and to an AC grid (100), said charger (1) being designed to operate by charging (G2V) and discharging (V2G) said battery (110).

Description

Technical Field

[0001] The present invention relates to a method for controlling a bidirectional battery charger. Background Art

[0002] Conventional battery chargers are unidirectional, which only allow the battery to be charged from an external power supply network, which is usually referred to as the charging direction or forward direction.

[0003] Such unidirectional battery chargers generally comprise a power factor correction stage (also referred to by its abbreviation PFC) and a DC-DC conversion stage (more generally referred to as a DC-DC stage).

[0004] However, it is advantageous that the battery charger can also deliver the stored power to an external grid as a current source, or replace the grid and operate as a voltage source to a connected load; this is referred to as a bidirectional charger, and in the context of motor vehicles, as V2X (for Vehicle to Everything) or V2G (for Vehicle to Grid). The supply of current from the battery to the external grid is called the discharge direction or reverse direction.

[0005] In particular, bidirectional chargers are known, such as the bidirectional charger in document FR3014260 A1, which describes an LC series resonant DC-DC charger. However, such a connection does not change the type of energy conversion, since its gain is always less than 1.

[0006] Bidirectional (or reversible) chargers for high power density applications are also known, such as the prior art Figures 1 to 3 As shown, a resonant full-bridge DC-DC LLC converter and a Vienna topology AC-DC converter are implemented.

[0007] Generally speaking, referring to the prior art Figures 1 to 3 , the bidirectional charger 1 is connected to both the battery 110 of the motor vehicle and can be connected to the AC power grid 100 .

[0008] The bidirectional charger 1 comprises a bidirectional AC-DC converter 130 linked to a bidirectional DC-DC converter 140 via a DC bus 150. The two converters 130, 140 are controlled by a control system 120 (also referred to as a controller).

[0009] Figure 2 The illustrated bidirectional AC-DC converter 130 includes a Vienna topology known in the art.

[0010] The Vienna topology (also called Vienna rectifier circuit) is one of the most commonly used three-phase power factor correctors (also called PFC, power factor correction) for high power applications.

[0011] like Figure 2As shown, the main elements of the topology of the three-level bidirectional Vienna rectifier are three amplifying inductors 131 , three phase branches 132 , three power bridge arms 135 and two DC link capacitors 133 , 134 .

[0012] Each phase leg 132 is composed of two MOSFETs to ensure bidirectional operation of the AC-DC converter. Each power bridge arm 135 is composed of two inverted series switches to allow bidirectional current flow.

[0013] according to Figure 3 The resonant full-bridge DC-DC LLC converter 140 includes a full-switching bridge 11 that generates a square wave signal or current to excite an LLC circuit 12, which is composed of a series capacitor Cr and two inductors, namely a series inductor Lr and an inductor Lm connected in parallel with the primary winding of a transformer 13. The LLC circuit 12 then generates a resonant sinusoidal current in the transformer 13, which is rectified by a rectifier bridge 14 and then transmitted to a battery 16, which is connected in parallel with a smoothing capacitor (not shown). The voltage across the terminals of the smoothing capacitor is called V bat , because it is equal to the voltage across the terminals of the battery 16. The input of the converter 11 (in charging mode) is connected to a voltage V DC The DC bus, which Figure 1 In other words, in the charging mode, the full bridge 11 is composed of a capacitor with a voltage of V DC The full bridge 11 includes four bidirectional switch units S1 to S4; the rectifier bridge 14 (in charging mode) is also a full bridge including four bidirectional switch units S5 to S8.

[0014] in other words, Figure 3 The illustrated bidirectional resonant DC-DC LLC converter 140 is composed of two full bridges separated by a transformer with a turns ratio equal to n and an interface between the battery voltage and the high voltage of the DC bus.

[0015] The resonant cavity is composed of a series capacitor Cr, a series inductor Lr and a magnetizing shunt inductor Lm.

[0016] C1 is the capacitor of the DC bus, V DC is the DC bus voltage, V bat is the voltage of the battery, and P is the power of the converter.

[0017] The resonant cavity is directly linked to a high-frequency transformer, which provides galvanic isolation for the charger.

[0018] The most commonly implemented modulation strategy for the resonant DC-DC LLC converter 140 is pulse frequency modulation, abbreviated as PFM. It consists in varying the switching frequency of the MOSFET control signal at a fixed duty cycle.

[0019] In the G2V mode, the power MOSFETs of the full bridge on the primary side of the transformer are additionally controlled with a duty cycle of 0.5, ignoring the dead time of the MOSFETs of the full bridge on the secondary side being turned OFF.

[0020] In V2G mode, the MOSFETs of the full bridge on the secondary side are controlled, while the MOSFETs of the full bridge on the primary side are in the off state.

[0021] Document FR1856534 develops a PFM control strategy based on a gain inversion method, ensuring a more stable response to DC current disturbances at the DC-DC input.

[0022] The feasible range of switching frequency is between 60 and 200 kHz to guarantee the so-called ZVS (zero voltage switching) condition. This frequency feasibility condition poses a problem for minimizing the costs associated with the implementation of software (particularly associated with the operation of the FPGA) and hardware (associated with the size of the charger) in the electric vehicle charger.

[0023] However, when the on-board battery charger adopts the PFM strategy for wide input / output range applications in G2V and V2G modes, a wider switching frequency range is required to meet the system voltage gain requirements in both charging directions.

[0024] This wider switching frequency range results in a loss of soft-switching operation, which reduces conversion efficiency and control performance.

[0025] Figure 4a and Figure 4b The switching frequency obtained using the gain inversion method described in document FR1856534 in G2V and V2G modes is shown relative to the variation of the voltage and power of the battery, respectively.

[0026] It is worth noting that Figure 4a and Figure 4b Both contain an operating region 20 , 20 ′, in which the control frequency saturates at 200 kHz, which is the maximum allowed switching frequency.

[0027] In the G2V mode, the size of the frequency saturation region is smaller during operation in the battery low voltage region and the low power region.

[0028] In V2G mode, there is a considerable frequency saturation region.

[0029] Operation in the saturation region results in low efficiency and can cause severe control errors of the DC bus voltage when using a PFM strategy.

[0030] Therefore, a solution needs to be found that can control the DC bus voltage of the bidirectional charger even if the LLC converter is saturated at frequencies above 200kHz, thus avoiding the DC bus from getting out of control. Summary of the invention

[0031] To this end, a method for controlling a bidirectional charger is proposed, the bidirectional charger including a bidirectional AC-DC converter connected to the bidirectional DC-DC converter via a DC bus, the charger being connected to both a battery and an AC grid, the charger being designed to work by charging and discharging the battery.

[0032] The method comprises the following steps: determining the operation region of the bidirectional DC-DC converter by selecting from a saturation region and a non-saturation region according to whether the operation mode of the charger is charging or discharging, according to the battery voltage, and according to the power of the battery;

[0033] The method implements a set of steps for controlling the voltage of the DC bus, the steps comprising:

[0034] - if the vehicle is operated in discharge mode and if the DC-DC converter is in the saturation region, phase shift modulation (abbreviated as PSM) control is adopted;

[0035] - if the vehicle is operating in charging mode (G2V) and if the DC-DC converter is in the saturation region, adding the output of the DC-DC DC bus controller to the power demand to perform power correction;

[0036] - If the vehicle is operated in a charging mode (G2V) or a discharging mode (V2G), and if the DC-DC converter is in a non-saturated region, pulse frequency modulation (PFM) control of the DC bus is performed, including:

[0037] - a sub-step of calculating a feedforward switching frequency obtained by gain inversion according to reference values ​​of the power of the DC-DC converter, the battery voltage and the voltage of the DC bus;

[0038] - A sub-step of calculating a control value of a proportional-integral controller according to a difference between the voltage of the DC bus and a reference value of the DC bus;

[0039] - A sub-step of adding the calculated control value to the feed-forward switching frequency to offset the voltage error of the DC bus;

[0040] - controlling the DC bus, including adding the power demand to the output of a DC bus controller.

[0041] The method also implements a set of steps for pulse width modulation (abbreviated as PWM) control of the network current, which steps include:

[0042] - Steps to calculate the input parameters to generate the reference current, calculated as follows:

[0043] o if the charger is operated in charging mode and if the DC-DC converter is in the saturation region, the input parameter is the sum of the power demand of the charger and the control value calculated for controlling the DC bus;

[0044] oOtherwise, the input parameter is the value of the power requirement of the charger;

[0045] - a step of generating a setpoint current as a function of the measured phase voltages and the calculated input parameters; and

[0046] - a step of controlling the current according to these set point currents adapted to define the duty cycle; and

[0047] - A step of performing pulse width modulation (PWM) control on the network currents according to the duty cycle, thereby providing a control signal for the bidirectional AC-DC converter.

[0048] Therefore, the charger can be controlled while taking into account the switching frequency saturation region of the bidirectional DC-DC converter without losing control of the DC bus.

[0049] Advantageously, when the charger operates in charging mode and the DC-DC converter is in the saturation region, the reference voltage of the DC bus is variable, depending on the measured battery voltage.

[0050] Specifically, since a change in the set point current may result in an output power higher than the maximum power being generated, the reference voltage of the DC bus may vary according to the battery voltage.

[0051] Specifically, the reference voltage is selected from a predetermined mapping. This allows the DC bus reference voltage to be quickly calculated in a charging mode when the DC-DC converter is in a saturation region.

[0052] Specifically, the phase shift modulation control includes:

[0053] - A sub-step of calculating a feed-forward phase shift obtained by gain inversion according to reference values ​​of the power of the DC-DC converter, the battery voltage and the voltage of the DC bus;

[0054] - a sub-step of calculating a phase control value by a proportional-integral controller according to a difference between the voltage of the DC bus and a reference value of the DC bus;

[0055] - A sub-step of adding the calculated phase control value to the feed-forward phase shift.

[0056] The invention also relates to a device for controlling a bidirectional charger, the bidirectional charger comprising a bidirectional AC-DC converter connected to the bidirectional DC-DC converter via a DC bus, the charger being connected both to a battery and to an AC grid, the charger being designed to work by charging and discharging the battery;

[0057] The device includes means for determining the operating region of the bidirectional DC-DC converter by selecting from a saturation region and a non-saturation region according to whether the operating mode of the charger is charging or discharging, according to the battery voltage, and according to the power of the battery;

[0058] The apparatus comprises means for implementing a set of steps for controlling the voltage of the DC bus, the steps comprising:

[0059] - if the vehicle is operated in discharge mode and if the DC-DC converter is in saturation region, adopting phase shift modulation PSM control;

[0060] - if the vehicle is operated in charging mode G2V and if the DC-DC converter is in the saturation region, adding the output of the DC-DC DC bus controller to the power demand to perform a power correction;

[0061] - If the vehicle is operated in a charging mode G2V or a discharging mode V2G, and if the DC-DC converter is in a non-saturated region, performing pulse frequency modulation PFM control on the DC bus, including:

[0062] - a sub-step of calculating a feedforward switching frequency obtained by gain inversion according to reference values ​​of the power of the DC-DC converter, the battery voltage and the voltage of the DC bus;

[0063] - A sub-step of calculating a control value of a proportional-integral controller according to a difference between the voltage of the DC bus and a reference value of the DC bus;

[0064] - A sub-step of adding the calculated control value to the feed-forward switching frequency to offset the voltage error of the DC bus;

[0065] The device also includes means for implementing a set of steps for pulse width modulation (PWM) control of the network current, the steps comprising:

[0066] - Steps to calculate the input parameters to generate the reference current, calculated as follows:

[0067] o if the charger is operated in charging mode and if the DC-DC converter is in the saturation region, the input parameter is the sum of the power demand of the charger and the control value calculated for controlling the DC bus;

[0068] oOtherwise, the input parameter is the value of the power requirement of the charger;

[0069] - a step of generating a setpoint current as a function of the measured phase voltages and the calculated input parameters; and

[0070] - a step of controlling the current according to these set point currents adapted to define the duty cycle; and

[0071] - A step of performing pulse width modulation (PWM) control on the network currents according to the duty cycle, thereby providing a control signal for the bidirectional AC-DC converter.

[0072] The control device may be an onboard computer, a processor, a microprocessor, an FPGA, a system on a chip (SoC) (standing for system embedded on a single integrated circuit), or a microcontroller.

[0073] The present invention also relates to an electrical system comprising a bidirectional charger comprising a bidirectional AC-DC converter connected to the bidirectional DC-DC converter via a DC bus, the charger being connected both to a battery and to an AC power grid, the charger being designed to operate by charging and discharging the battery; the electrical system also comprises a control device as described above.

[0074] The present invention also relates to an electric vehicle comprising the electrical system as described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0075] Other characteristics and advantages of the invention will become apparent on reading the description given below of a particular embodiment of the invention, provided by way of non-limiting illustration, with reference to the accompanying drawings, in which:

[0076] [ Figure 1 ] is a schematic representation of a bidirectional charger known in the prior art;

[0077] [ Figure 2 ] is based on Figure 1 A schematic diagram of a bidirectional AC-DC converter of a charger;

[0078] [ Figure 3 ] is based on Figure 1 A schematic diagram of a bidirectional DC-DC converter of a charger;

[0079] [FIG. 4A] and [FIG. 4B] are Figure 3The switching frequency of the bidirectional DC-DC converter is Figure 1 Representation of the functional relationship between battery voltage and charger power;

[0080] [ Figure 5 ]yes Figure 3 Schematic representation of the so-called pulse frequency modulation control of a DC-DC converter;

[0081] [ Figure 6 ]yes Figure 3 Schematic representation of the so-called phase-shift modulation control of a DC-DC converter;

[0082] [ Figure 7 ]yes Figure 2 Schematic representation of the so-called pulse width modulation control of an AC-DC converter;

[0083] [ Figure 8 ]yes Figure 2 A schematic representation of another so-called pulse width modulation control of an AC-DC converter; and

[0084] [ Fig. 9 ] is the DC bus reference voltage V dc ref The mapping representation with the battery voltage Vbat. DETAILED DESCRIPTION

[0085] The present invention proposes according to the prior art Figures 1 to 3 And the bidirectional charger 1 is controlled as described above.

[0086] To this end, in normal operation, two independent control strategies are used to control the converter:

[0087] 1- DC-DC LLC converter stage for controlling the DC bus

[0088] 2-AC-DC converter stage with Vienna topology for controlling the network current.

[0089] In a preliminary step, the method implements the following steps: determining the operation area of ​​the bidirectional DC-DC converter (140) by selecting from a saturation area (20, 20') and a non-saturation area according to whether the operation mode of the charger (1) is charging or discharging, according to the battery voltage (Vbat) and according to the power (P) of the battery.

[0090] Especially reference Figure 4a and Figure 4b , considering the desired operating mode, it is determined whether the DC-DC converter will operate in its saturation region.

[0091] Based on this determination, the method will proceed as follows:

[0092] 1) When the charger is operating at the charging capacity (G2V)

[0093] a. If the DC-DC converter is in the saturation region

[0094] i. Use strategies for controlling AC-DC converters to control the DC bus, such as Figure 8 As shown. The control of the DC bus is added to the power demand to generate a new current set point. The PWM strategy of the AC-DC converter will then adjust the network current and DC bus voltage, just like cascade control;

[0095] ii. Controlling the network current according to the DC bus controller, as described below;

[0096] b. If the DC-DC converter is not in the saturation region

[0097] i. Use PFM method to control DC bus;

[0098] ii. Use PWM control to control the network current;

[0099] 2) When the charger is operating at discharge capacity

[0100] a. If the DC-DC converter is in the saturation region

[0101] i. Use the PSM method to control the DC bus;

[0102] ii. Use PWM control to control the network current;

[0103] b. If the DC-DC converter is not in the saturation region

[0104] i. Use PFM method to control DC bus;

[0105] ii. Use PWM control to control the network current.

[0106] All of these controls are described in more detail below.

[0107] As for the DC-DC LLC converter stage, the LLC converter is controlled by implementing a gain inversion based PFM strategy.

[0108] refer to Figure 5 , this PFM strategy is adopted when the charger operates in the charging mode G2V if the DC-DC LLC converter is in the non-saturation region, and in the discharging mode V2G if the DC-DC LLC converter is in the non-saturation region.

[0109] The method comprises controlling the voltage V of the DC bus by varying the switching frequency f dc .

[0110] Therefore, according to the converter power P, battery voltage V bat and the DC bus voltage reference Calculation 51 The “feed-forward” switching frequency f obtained by gain inversion 0 .

[0111] The frequency is added 53 to the output ΔF of the proportional-integral PI controller 52 to cancel the voltage error of the DC bus.

[0112] The input terminal of the PI controller 52 receives the battery voltage V bat The voltage reference to the DC bus The error between .

[0113] However, when the operating point is in the saturation region 20 of both operating modes during charging G2V and discharging V2G, the control accuracy of the DC bus voltage is lost because the switching frequency is saturated at 200 kHz, which is the maximum switching frequency allowed.

[0114] When the charger is operating in discharge mode and is in the saturation region, the PSM method will be implemented, referring to Figure 6 , as described in the following scientific publication: H.A. Attar, M. Ghanes, M. Hamida, and M. Taleb, “Control strategies design and comparison of DC-DC LLC converter in V2X mode for electric vehicle charger application,” 2021 IEEE Conference on Control Techniques and Applications (CCTA), 2021, pp. 1154-1159, doi:10.1109 / CCTA48906.2021.9659000.

[0115] PSM control includes:

[0116] The feedforward phase shift θ obtained by gain inversion is calculated 61 based on the power of the DC-DC converter 140, the battery voltage Vbat and the reference value VDCref of the voltage of the DC bus. 0 ;

[0117] calculating 62 a phase control value through a proportional-integral (PI) controller according to a difference between a voltage of the DC bus and a reference value of the DC bus;

[0118] And the calculated phase control value Δ θ 63 is added to the feedforward phase shift.

[0119] At the AC-DC conversion stage with Vienna topology, the AC-DC converter is controlled based in particular on the control law disclosed in prior art application FR 3 061 819 A1.

[0120] refer to Figure 7 and Figure 8 , implements the generation of set point currents for AC-DC control strategies Steps 71 and 81, wherein x∈[1,3], x represents the electrical phase.

[0121] The set point current is calculated in two ways depending on the charger operation mode and the DCDC operation area.

[0122] To do this, define the input parameters for generating the reference current, calculated as follows:

[0123] If the charger is operated in charging mode G2V and if the DC-DC converter is in the saturation region, the input parameter is the power demand P of the charger. ref and the sum 80 of the calculated control values ​​for controlling the DC bus, such as Figure 8 shown.

[0124] The output of the DC bus controller therefore represents a power correction, allowing a new current set point to be generated.

[0125] In other words, in G2V charging mode and saturation region, frequency correction is not implemented but power correction is implemented. Therefore, the PWM strategy of the AC-DC converter will control the network current and DC bus voltage similar to cascade control.

[0126] Otherwise, the input parameter is the charger power demand P ref The value of Figure 7 shown.

[0127] Therefore, according to the phase voltage The measured values ​​and input parameters (x, y represent two different phases) generate the set point current

[0128] A step 82 of controlling the current is then implemented, allowing definition of the duty cycle D, D* required to control the sinusoidal network current.

[0129] These duty cycles D, D* are based on the generated set point current And according to the phase current The measured values ​​and phase voltage The measured value is calculated.

[0130] The PWM strategy 73 is then implemented to generate a control signal for the MOSFET according to the calculated duty cycle D.

[0131] Therefore, the PWM is used to generate control signals Sx of the network current, which control signals Sx control the bidirectional AC-DC converter 130 .

[0132] However, in this strategy, it is assumed that the DC bus voltage at the output of the AC-DC PFC converter stage is constant because the DC-DC LLC converter controls it.

[0133] However, in charging mode G2V and if the DC-DC converter is in the saturation region, or the input parameters depend on the power demand P of the charger ref and the calculated control value for controlling the DC bus, a change in the set point current will still result in an output power higher than the maximum power being produced.

[0134] Therefore, to avoid this problem, the reference V of the DC bus is modified based on a predetermined mapping. dc ref The predetermined mapping provides a reference V for the DC bus according to the battery voltage Vbat. dc ref .

[0135] The DC bus reference V dc ref An example of a change relative to the battery voltage is Fig. 9 shown.

Claims

1. A method for controlling a bidirectional charger (1), the method comprising a bidirectional AC-DC converter (130) connected to a bidirectional DC-DC converter (140) via a DC bus (150), the charger being connected to both a battery (110) and an AC grid (100), the charger (1) being designed to operate by charging (G2V) and discharging (V2G, V2X) the battery (110); The method comprises the following steps: Determining the operation area of ​​the bidirectional DC-DC converter (140) by selecting from a saturation area (20, 20') and a non-saturation area according to whether the operation mode of the charger (1) is charging or discharging, according to the battery voltage (Vbat) and according to the power (P) of the battery; The method implements a set of steps for controlling the voltage of the DC bus (150), the steps comprising: - if the vehicle is operated in discharge mode (V2G) and if the DC-DC converter is in saturation region, phase shift modulation (PSM) control is adopted; - if the vehicle is operating in charging mode (G2V) and if the DC-DC converter is in the saturation region, adding the output of the DC-DC DC bus controller to the power demand to perform power correction; - If the vehicle is operated in a charging mode (G2V) or a discharging mode (V2G), and if the DC-DC converter is in a non-saturated region, pulse frequency modulation (PFM) control of the DC bus is performed, including: - According to the power of the DC-DC converter (140), the battery voltage (Vbat) and the reference value of the voltage of the DC bus (V DC ref ) to calculate the feedforward switching frequency (f0) obtained by gain inversion sub-step (51); - a sub-step (52) of calculating a control value of a proportional-integral (PI) controller as a function of the difference between the voltage of the DC bus and a reference value of the DC bus; - A sub-step (53) of adding the calculated control value to the feedforward switching frequency to cancel the voltage error of the DC bus; The method also implements a set of steps for PWM control of the network current (100), the steps comprising: - Steps to calculate the input parameters to generate the reference current, calculated as follows: o If the charger is operating in charging mode (G2V) and if the DC-DC converter is in the saturation region, the input parameter is the charger power demand (P ref ) and a sum (80) of a calculated control value for controlling the DC bus; oOtherwise, the input parameter is the power requirement of the charger (P ref ) value; - a step (71, 81) of generating a setpoint current as a function of the measured phase voltages and the calculated input parameters; and - a step (82) of current control of a current suitable for defining a duty cycle (D*) according to these setpoint currents; and - A step (73) of pulse width modulation control (73) of these network currents according to said duty cycle (D*), thereby providing a control signal for the bidirectional AC-DC converter (130).

2. The method according to claim 1, characterized in that When the charger (1) operates in the charging mode (G2V) and the DC-DC converter is in the saturation region, the reference voltage (V DC ref ) is variable, depending on the measured battery voltage (Vbat).

3. The method according to claim 2, characterized in that The reference voltage is selected from a predetermined map.

4. The method according to any one of claims 1 to 3, characterized in that The phase shift modulation (PSM) control includes: - a sub-step (61) of calculating a feedforward phase shift (teta0) obtained by gain inversion according to the power of the DC-DC converter (140), the battery voltage (Vbat) and a reference value (VDCref) of the voltage of the DC bus; - a sub-step (62) of calculating a phase control value by a proportional integral (PI) controller according to the difference between the voltage of the DC bus and a reference value of the DC bus; - A sub-step (63) of adding the calculated phase control value to the feed-forward phase shift.

5. A device (120) for controlling a bidirectional charger (1), comprising a bidirectional AC-DC converter (130) connected to a bidirectional DC-DC converter (140) via a DC bus (150), the charger being connected both to a battery (110) and to an AC grid (100), the charger (1) being designed to operate by charging (G2V) and discharging (V2G, V2X) the battery (110); The device (120) comprises means for determining the operating region of the bidirectional DC-DC converter (140) by selecting from a saturated region (20, 20') and a non-saturated region according to whether the operating mode of the charger (1) is charging or discharging, according to the battery voltage (Vbat) and according to the power (P) of the battery; The apparatus (120) comprises means for implementing a set of steps for controlling the voltage of the DC bus (150), the steps comprising: - if the vehicle is operated in discharge mode (V2G) and if the DC-DC converter is in saturation region, phase shift modulation (PSM) control is adopted; - if the vehicle is operating in charging mode (G2V) and if the DC-DC converter is in the saturation region, adding the output of the DC-DC DC bus controller to the power demand to perform power correction; - If the vehicle is operated in a charging mode (G2V) or a discharging mode (V2G), and if the DC-DC converter is in a non-saturated region, pulse frequency modulation (PFM) control of the DC bus is performed, including: - According to the power of the DC-DC converter (140), the battery voltage (Vbat) and the reference value of the DC bus voltage (V DC ref ) to calculate the feedforward switching frequency (f0) obtained by gain inversion sub-step (51); - a sub-step (52) of calculating a control value of a proportional-integral (PI) controller as a function of the difference between the voltage of the DC bus and a reference value of the DC bus; - A sub-step (53) of adding the calculated control value to the feedforward switching frequency to cancel the voltage error of the DC bus; The device (120) also includes means for implementing a set of steps for pulse width modulation (PWM) control of the network current (100), the steps comprising: - Steps to calculate the input parameters to generate the reference current, calculated as follows: o If the charger is operating in charging mode (G2V) and if the DC-DC converter is in the saturation region, the input parameter is the charger power demand (P ref ) and a sum (80) of a calculated control value for controlling the DC bus; oOtherwise, the input parameter is the power requirement of the charger (P ref ) value; - a step (71, 81) of generating a setpoint current as a function of the measured phase voltages and the calculated input parameters; and - a step (82) of current control of a current suitable for defining a duty cycle (D*) according to these setpoint currents; and - a step (73) of pulse width modulation control (73) of these network currents according to the duty cycle (D*), thereby providing the bidirectional AC-DC converter (130) Provides control signals.

6. An electrical system comprising a bidirectional charger (1), the bidirectional charger comprising a bidirectional AC-DC converter (130) connected to a bidirectional DC-DC converter (140) via a DC bus (150), the charger being connected to both a battery (110) and an AC grid (100), the charger (1) being designed to operate by charging (G2V) and discharging (V2G, V2X) the battery (110); the electrical system further comprising a control device according to claim 5.

7. An electric vehicle comprising the electrical system according to claim 6.

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