Method for controlling a bidierectional electrical charger

Abstract

Method for controlling (120) a bidirectional charger (1) comprising a bidirectional AC-DC converter (130) connected via a DC Bus (150) to a bidirectional DC-DC converter (140), said charger being connected both to an electric battery (110) and to an AC power grid (100), and said charger (1) being designed to work in charging (G2V) and in discharging (V2G) mode of said battery (110).

Description

Description Title of the invention: Method for controlling a bidirectional electric charger. [1] The present invention relates to a method for controlling a bidirectional electric accumulator battery charger. [2] A conventional electric storage battery charger is unidirectional in the sense that it only allows electric storage batteries to be recharged from an external power supply network, commonly referred to as the charging direction or forward direction. [3] Such a unidirectional electric storage battery charger generally comprises a power factor correction stage, also known by its English abbreviation PFC, and a direct-to-direct conversion stage, more generally called a DC-DC stage. [4] However, it is useful that battery chargers can also deliver the accumulated electricity to an external electrical network, as a current source, or replace a network and operate as a voltage source to which loads are connected; we then speak of bidirectional chargers and in the context of motor vehicles used V2X, for Vehicle to everything or V2G for Vehicle to Grid. The supply of current by the electric storage battery to the external network is called the discharge direction, or indirect direction. [5] We know in particular of bidirectional chargers, such as that in the document FR3014260 Al, which describes a resonant DC-DC charger of the LC series type. However, such an assembly does not allow changing the type of energy conversion because its gain is always less than 1. [6] A bidirectional (or reversible) charger for high power density applications is also known, as shown in Figures 1 to 3 of the prior art, which implements a full-bridge resonant LLC type DC-DC converter and a Vienna topology AC-DC converter. [7] Generally speaking a bidirectional charger 1, with reference to figures 1 to 3 of prior art, is connected on the one hand to the battery 110 of the motor vehicle and on the other hand is intended to be able to be connected to an alternating electrical network 100. [8] This bidirectional charger 1 includes a bidirectional AC-DC converter 130 connected by a continuous bus 150, called DC bus 150, to a DC-DC converter bidirectional 140. These two converters 130,140 are controlled by a control device, also called controller 120. [9] The bidirectional AC-DC converter 130 shown in Figure 2 comprises a Vienna topology known from the prior art.

[0010] The Vienna topology, also called the 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] As shown in Figure 2, the main components of the three-level bidirectional Vienna rectifier topology are three amplification inductors 131, three phase branches 132, three power bridge branches 135 and two capacitors 133, 134 on the DC side.

[0012] Each phase branch 132 consists of two MOSFETs that ensure bidirectional operation of the AC-DC converter. Each power bridge branch 135 consists of two inverted series switches that allow bidirectional current flow.

[0013] The full-bridge resonant DC-DC LLC converter 140, according to Figure 3, comprises a full switching bridge 11 generating a square signal or current exciting an LLC circuit 12, composed of a series capacitor Cr and two inductors, a series inductor Lr and an inductor Lm in parallel with the primary winding of a transformer 13. The LLC circuit 12 then produces a resonant sinusoidal current in the transformer 13 which is rectified by the rectifier bridge 14, then transmitted to the battery 16, connected in parallel to a smoothing capacitor not shown. The voltage across this smoothing capacitor is referenced Vbat because it is equal to the voltage across the battery 16. The converter 11 is connected at the input (in the charging mode) to a DC bus of voltage VDC represented by a capacitor in Figure 1.In other words, in charge mode, the complete bridge 11 is powered by this continuous voltage bus VDC. The complete bridge 11 comprises four bidirectional switching cells SI to S4, the rectifier bridge 14 (in charge mode) is also a complete bridge comprising four bidirectional switching cells S5 to S8.

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

[0015] The resonant tank consists of a series capacitor Cr, a series inductance Lr, a magnetizing parallel inductance Lm.

[0016] Cl is the DC bus capacitor, VDC is the DC bus voltage, Vbat is the battery voltage, and P is the converter power.

[0017] The resonant tank is directly connected to a high frequency transformer which provides galvanic isolation of the charger.

[0018] For LLC 140 resonant DC-DC converters, the most commonly implemented modulation strategy is Pulse Frequency Modulation, commonly known as Pulse Frequency Modulation (PFM). It involves varying the switching frequency of the MOSFET control signals with a fixed duty cycle.

[0019] In G2V mode, the full-bridge power MOSFETs on the primary side of the transformer are driven in complement with a duty cycle of 0.5 ignoring the dead time, where the full-bridge MOSFETs on the secondary side are open (OFF).

[0020] In V2G mode, the secondary side full bridge MOSFETs are driven and the primary side full bridge MOSFETs are open.

[0021] A PFM control strategy based on a gain inversion method has been developed in FRI 856534 ensuring a more stable response to DC disturbances at the DC-DC input.

[0022] The switching frequency feasibility zone is between 60 and 200 kHz to ensure the so-called Z VS (Zero Voltage Switching) condition. This frequency feasibility condition is a problem in minimizing the costs related to software implementation (especially related to the operation of the FPGA) and hardware (concerning the charger sizing) in the electric vehicle charger.

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

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

[0025] Figures 4a and 4b represent the switching frequencies obtained from the gain inversion method described in FRI 856534, respectively in G2V and V2G modes with respect to battery voltage and power variations.

[0026] It is noted that in each figure 4a and 4b there is an operating zone 20, 20' where the control frequency is saturated at 200 kHz, which is the maximum authorized switching frequency.

[0027] In G2V mode, there is a small area of ​​frequency saturation when operating in the low battery voltage and low power region.

[0028] In V2G mode, there is a significant frequency saturation zone.

[0029] Operation in the saturation zone generates low efficiency and causes a significant error in regulating the DC bus voltage with the PFM strategy.

[0030] Also there is a need to find a solution to allow the DC bus voltage of a bidirectional charger to be regulated even when the LLC converter is saturated at frequencies above 200KHz, thus avoiding a loss of DC bus regulation.

[0031] To this end, a method is proposed for regulating a bidirectional charger comprising a bidirectional AC-DC converter connected by a DC bus to a bidirectional DC-DC converter, said charger being connected on the one hand to an electric battery and on the other hand to an alternating electrical network, said charger being adapted to operate in charging and discharging of said battery.

[0032] The method comprises a step of determining an operating zone of the bidirectional DC-DC converter, chosen from a saturated zone and an unsaturated zone, as a function of the operating mode of the charger, in charge or in discharge, as a function of the battery voltage and as a function of the battery power; the method implements a set of steps of regulating the DC bus voltage comprising: - if the vehicle operates in discharge mode and if the DC-DC converter is in a saturated zone, regulation by modulation by phase change, more generally known by its English name of Phase Shift Modulation, abbreviated PSM; - if the vehicle is operating in charge mode (G2V) and if the DC-DC converter is in a saturated zone, the output of the DC-DC bus regulator is added to the power demand in order to carry out a power correction; - if the vehicle operates in charge (G2V) or discharge (V2G) mode and if the DC-DC converter is in an unsaturated zone, regulation of the DC bus by pulse frequency modulation (PFM) including: - A sub-step of calculating a feedforward switching frequency obtained by inverting the gain as a function of the power of the DC-DC converter, the battery voltage and a reference value of the DC bus voltage; - A sub-step of calculating a regulation value of a proportional-integral regulator, depending on the difference between the DC bus voltage and the DC bus reference value; - a sub-step of summing the regulation value calculated with the feedforward switching frequency, so as to cancel the DC bus voltage error; - DC bus regulation including the addition of power demand to the DC bus regulator output. The method also implements a set of steps for regulating network currents by Pulse Width Modulation, known as ML1 or generally known by its English name of Pulse Wide Modulation, abbreviated PWM, including: - A step of calculating an input parameter to generate reference currents, calculated so that: o If the charger is operating in charging mode and if the DC-DC converter is in a saturated zone, the input parameter is the sum of the charger power demand with the regulation value calculated for the DC bus regulation; o Otherwise, the input parameter is the value of the charger's power demand; - A step for generating setpoint currents as a function of the measured phase voltages and the calculated input parameter; and - A current regulation step adapted to define duty cycles according to the setpoint currents; and - A step of regulating the network currents by pulse width modulation ML! as a function of said duty cycles, providing control signals for the bidirectional AC-DC converter.

[0033] This allows the charger to be controlled taking into account the switching frequency saturation zones of the bidirectional DC-DC converter without loss of DC bus regulation.

[0034] Advantageously, when the charger is operating in charge mode and when the DC-DC converter is in a saturated zone, the reference voltage of the DC bus is variable, depending on the measured battery voltage.

[0035] In fact, the variation in the setpoint current leading to the generation of an output power greater than the maximum power, the reference of the DC bus is varied according to the battery voltage.

[0036] In particular, said reference voltage is chosen from a predetermined map. This allows a rapid calculation of the reference voltage of the DC bus in the case of charging mode with DC-DC converter in saturated zone.

[0037] In particular, phase change modulation regulation includes: - A sub-step of calculating a feedforward phase shift obtained by inverting the gain as a function of the power of the DC-DC converter, the battery voltage and the reference value of the DC bus voltage; - A sub-step of calculating a phase regulation value by a proportional-integral regulator, depending on the difference between the DC bus voltage and the DC bus reference value; - a sub-step of summing the phase regulation value calculated with the feedforward phase shift.

[0038] The invention also relates to a device for regulating a bidirectional charger comprising a bidirectional AC-DC converter connected by a DC bus to a bidirectional DC-DC converter, said charger being connected on the one hand to an electric battery and on the other hand to an alternating electrical network, said charger being adapted to operate in charging and discharging said battery; The device comprising means for determining an operating zone of the bidirectional DC-DC converter, chosen from a saturated zone and an unsaturated zone, as a function of the operating mode of the charger, in charge or in discharge, as a function of the battery voltage and as a function of the battery power; the device comprising means for implementing a set of steps for regulating the DC bus voltage comprising: - if the vehicle operates in discharge mode and if the DC-DC converter is in a saturated zone, regulation by phase change modulation PSM, - if the vehicle is operating in G2V charging mode and if the DC-DC converter is in a saturated zone, the output of the DC-DC bus regulator is added to the power demand in order to carry out a power correction; - if the vehicle operates in G2V charge or V2G discharge mode and if the DC-DC converter is in an unsaturated zone, regulation of the continuous bus by PFM pulse frequency modulation including: - A sub-step of calculating a feedforward switching frequency obtained by inverting the gain as a function of the power of the DC-DC converter, the battery voltage and a reference value of the DC bus voltage; - A sub-step of calculating a regulation value of a proportional-integral regulator, depending on the difference between the DC bus voltage and DC bus reference value; - a sub-step of summing the regulation value calculated with the feedforward switching frequency, so as to cancel the DC bus voltage error; The device also comprising means for implementing a set of steps for regulating the network currents by pulse width modulation PWM comprising: - A step of calculating an input parameter to generate reference currents, calculated so that: o If the charger is operating in charge mode and if the DC-DC converter is in a saturated zone, the input parameter is the sum of the charger power demand with the regulation value calculated for the DC bus regulation; o Smon, the input parameter is the value of the charger power demand; - A step for generating setpoint currents as a function of the measured phase voltages and the calculated input parameter; and - A current regulation step adapted to define duty cycles according to the setpoint currents; and - A step of regulating the network currents by pulse width modulation PWM as a function of said duty cycles, providing control signals for the bidirectional AC-DC converter.

[0039] The control device can be an on-board computer, a processor, a microprocessor, an FPGA, a “System on a Chip” (SoC) to name a system embedded on a single integrated circuit, or a microcontroller.

[0040] The invention also relates to an electrical system comprising a bidirectional charger comprising a bidirectional AC-DC converter connected by a DC bus to a bidirectional DC-DC converter, said charger being connected on the one hand to an electric battery and on the other hand to a network. alternating electric power, said charger being adapted to operate in charging and discharging said battery, the electrical system also comprising a regulating device as described previously.

[0041] The invention also relates to an electric motor vehicle comprising an electrical system as described above.

[0042] Other features and advantages of the invention will emerge from reading the description given below of a particular embodiment of the invention, given for informational purposes but not as a limitation, with reference to the appended drawings in which:

[0043] [Fig. 1] is a schematic representation of a bidirectional charger known from the prior art;

[0044] [Fig. 2] is a schematic view of a bidirectional AC-DC converter of a charger according to Fig. 1;

[0045] [Fig. 3] is a schematic view of a bidirectional DC-DC converter of a charger according to Fig. 1;

[0046] [Fig. 4a] and [Fig. 4b] are representations of the switching frequencies of the bidirectional DC-DC converter of Figure 3 as a function of the battery voltage and the charger power of Figure 1;

[0047] [Fig. 5] is a schematic representation of a so-called pulse frequency modulation regulation of the DC-DC converter of Figure 3;

[0048] [Fig. 6] is a schematic representation of a so-called phase-shift modulation regulation of the DC-DC converter of Figure 3;

[0049] [Fig. 7] is a schematic representation of a so-called pulse width modulation regulation of the AC-DC converter of Figure 2;

[0050] [Fig. 8] is a schematic representation of another so-called pulse width modulation regulation of the AC-DC converter of Fig. 2; and

[0051] [Fig. 9] is a representation of a map of the reference voltage of the direct bus Vdc ref depending on the battery voltage Vbat.

[0052] The invention proposes to control a bidirectional charger 1 according to figures 1 to 3 of prior art and as explained previously.

[0053] For this purpose, in its nominal operation, the converter is controlled using two independent control strategies:

[0054] 1- the DC-DC LLC converter stage to regulate the DC bus

[0055] 2- the AC-DC converter with Vienna topology stage to regulate the network currents.

[0056] In a preliminary step, the method implements a step of determining an operating zone of the bidirectional DC-DC converter (140), chosen from a saturated zone (20, 20') and an unsaturated zone, as a function of the operating mode of the charger (1), in charge or in discharge, as a function of the battery voltage (Vbat) and as a function of the power (P) of the battery.

[0057] In particular with reference to figures 4a and 4b, it is determined, taking into account the desired operating mode, whether the DC-DC converter will work in its saturated zone or not.

[0058] Depending on this determination, the process will proceed as follows: 1) When the charger is operating in load (G2V) a. If the DC-DC converter is in a saturated zone i. The DC bus regulation is performed by the control strategy of the AC-DC converter, as shown in Figure 8. The DC bus regulation is added to the power demand to generate the new current setpoint. Then the PWM strategy of the AC-DC converter will regulate the grid current and the DC bus voltage, like a cascade control; ii. The regulation of the grid currents is performed according to the DC bus regulator, as described below; b. If the DC-DC converter is not in a saturated zone i. The DC bus regulation is performed by a PFM method; ii. The regulation of the grid currents is performed by a PWM regulation; 2) When the charger is operating in discharge mode a. If the DC-DC converter is in a saturated zone i. The DC bus regulation is carried out by the PSM method; ii. The network current regulation is carried out by PWM regulation; b. If the DC-DC converter is not in a saturated zone i. The regulation of the DC bus is carried out by a PFM method; ii. The regulation of network currents is carried out by a PWM regulation.

[0059] All these regulations are described in more detail below.

[0060] With regard to the DC-DC LLC converter stage, the LLC converter is controlled by implementing a PFM strategy, based on gain inversion.

[0061] This PFM strategy, with reference to Figure 5, is employed here when the charger is operating in G2V charge mode, if the LLC DCDC converter is in an unsaturated zone, and in V2G discharge mode if the LLC DCDC converter is in an unsaturated zone.

[0062] This approach involves regulating the DC bus voltage V dc by varying the switching frequency f.

[0063] Thus, a feedforward switching frequency f0 is calculated (51) obtained by inverting the gain as a function of the converter power P and the battery voltage V. bat and the DC bus voltage reference V dCre ^..

[0064] It is added 53 to an output of the PI Proportional-Integral controller 52, AF to cancel the DC bus voltage error.

[0065] This PI 52 controller receives as input the error between the battery voltage V batand the DC bus voltage reference V dCre ^.

[0066] However, the accuracy of the DC bus voltage regulation is lost when the operating point is in the saturation zones of both operating modes, G2V load and V2G discharge, because the switching frequency is saturated at 200 kHz, which is the maximum permissible switching frequency.

[0067] When the charger operates in discharge mode and in a saturated zone, we then implement, with reference to Figure 6, a PSM approach, as described in the scientific publication HA 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 Technology and Applications (CCTA), 2021, pp. 1154-1159, doi: 10.1109 / CCTA48906.2021.9659000.

[0068] PSM regulation includes:

[0069] Calculation 61 of a feedforward phase shift 60 obtained by inverting the gain as a function of the power of the DC-DC converter 140, the battery voltage Vbat and the reference value of the DC bus voltage VDCref;

[0070] Calculation 62 of a phase regulation value by a PI proportional integral regulator, depending on the difference between the DC bus voltage and the DC bus reference value;

[0071] And the summation 63 of the phase regulation value calculated with the feedforward phase shift

[0072] At the level of the AC-DC conversion stage with Vienna topology, the AC-DC converter is controlled in particular on the basis of the control law disclosed in the prior art application FR3061819 AL

[0073] With reference to figures 7 and 8, a generation step 71, 81 of the reference currents i is implemented. xr ^ for the AC-DC control strategy, with x G [1,3], x indicating the electrical phase.

[0074] The setpoint currents i x r ^ are calculated in two ways depending on the charger's operating mode and the DCDC operating zone.

[0075] To this end, an input parameter is defined to generate reference currents, calculated such that:

[0076] If the charger is operating in G2V charging mode and the DC-DC converter is in a saturated zone, the input parameter is the sum of 80 of the charger's power demand P re f with the regulation value calculated for the regulation of the continuous bus as shown in Figure 8.

[0077] Thus, the output of the DC bus regulator represents a power correction that allows the new current setpoint to be generated.

[0078] In other words, in G2V charging mode and in a saturated zone, a frequency correction is not implemented but a power correction. Thus, the PWM strategy of the AC-DC converter will regulate the network current and the DC bus voltage, by analogy with a cascade control.

[0079] Otherwise, the input parameter is the value of the charger power demand P re f, as shown in Figure 7.

[0080] Thus, the setpoint currents i x r ^ , i x e ^ are generated based on the measurement of the phase voltage U™y S (x, y representing two phases different) and the input parameter.

[0081] A current regulation step 82 is then implemented to define the necessary duty cycles D, D* for controlling the sinusoidal network currents.

[0082] These duty cycles D, D* are calculated based on the generated setpoint currents i x r , i x r ^ and depending on the measurement of phase current i™ es and the measurement of the phase voltage U X y S .

[0083] A strategy is then implemented by ML1 or PWM 73, to generate the MOSFET control signals according to the calculated duty cycles D.

[0084] This PWM thus makes it possible to generate the Sx regulation signals for the network currents, these Sx regulation signals controlling the bidirectional AC-DC converter 130.

[0085] In this strategy, however, it is assumed that the DC bus voltage at the output of the PFC AC-DC converter stage is constant, since the LLC DC-DC converter controls it.

[0086] However in G2V charge mode and if the DC-DC converter is in a saturated zone, or the input parameter is a function of the power demand of the charger P re f and the calculated regulation value for the DC bus regulation, the variation of the setpoint current, however, results in the generation of an output power greater than the maximum power.

[0087] Also, in order to avoid this problem, the reference of the continuous bus Vdc ref is modified on the basis of a predetermined mapping, which gives the reference of the continuous bus Vd C ref depending on the battery voltage Vbat. An example of variation of the Vdc continuous bus reference ref versus battery voltage is shown in Figure 9.

Claims

Claims

1. Method for regulating a bidirectional charger (1) comprising a bidirectional AC-DC converter (130) connected by a DC bus (150) to a bidirectional DC-DC converter (140), said charger being connected on the one hand to an electric battery (110) and on the other hand to an AC electrical network (100), said charger (1) being adapted to operate in charging (G2V) and discharging (V2G, V2X) of said battery (110); The method comprising a step of determining an operating zone of the bidirectional DC-DC converter (140), chosen from a saturated zone (20, 20') and an unsaturated zone, as a function of the operating mode of the charger (1), in charge or in discharge, as a function of the battery voltage (Vbat) and as a function of the power (P) of the battery; The method implements a set of steps for regulating the voltage of the DC bus (150) comprising: - if the vehicle operates in discharge mode (V2G) and if the DC-DC converter is in a saturated zone, regulation by phase change modulation (PSM); - if the vehicle is operating in charge mode (G2V) and if the DC-DC converter is in a saturated zone, the output of the DC-DC bus regulator is added to the power demand in order to carry out a power correction; - if the vehicle operates in charge (G2V) or discharge (V2G) mode and if the DC-DC converter is in an unsaturated zone, regulation of the DC bus by pulse frequency modulation (PFM) including: - A sub-step of calculating (51) a feedforward switching frequency (fO) obtained by inverting the gain as a function of the power of the DC-DC converter (140), the battery voltage (Vbat) and a reference value of the DC bus voltage (Voc ref ) ; - A sub-step of calculation (52) of a regulation value of a proportional integral (PI) regulator, function of the difference between the DC bus voltage and the DC bus reference value; - a sub-step of summing (53) the regulation value calculated with the feedforward switching frequency, so as to cancel the DC bus voltage error; The method also implementing a set of steps for regulating the network currents (100) by PWM comprising: - A step of calculating an input parameter to generate reference currents, calculated so that: o If the charger operates in charge mode (G2 V) and if the DC-DC converter is in a saturated zone, the input parameter is the sum (80) of the charger's power demand (P ref) with the calculated regulation value for the DC bus regulation; o Otherwise, the input parameter is the value of the charger power demand - A step of generating (71, 81) setpoint currents as a function of the measured phase voltages and the calculated input parameter; and - A current regulation step (82) adapted to define duty cycles (D*) as a function of the setpoint currents; and - A step of regulating (73) the network currents by pulse width modulation (73) as a function of said duty cycles (D*), providing control signals for the bidirectional AC-DC converter (130).

2. Method according to claim 1, characterized in that when the charger (1) operates in charge mode (G2V) and when the DC-DC converter is in a saturated zone, the reference voltage of the DC bus (Voc ref) is variable, depending on the measured battery voltage (Vbat).

3. Method according to claim 2, characterized in that said reference voltage is chosen from a predetermined map.

4. Method according to any one of claims 1 to 3 characterized in that the regulation by phase change modulation (PSM) comprises: - A sub-step of calculating (61) a feedforward phase shift (tetaO) obtained by inverting the gain as a function of the power of the DC-DC converter (140), the battery voltage (Vbat) and the reference value of the DC bus voltage (VDCref); - A sub-step of calculating (62) a phase regulation value by a proportional integral (PI) regulator, a function of the difference between the DC bus voltage and the DC bus reference value; - a summation sub-step (63) of the phase regulation value calculated with the feedforward phase shift.

5. Device (120) for regulating a bidirectional charger (1) comprising a bidirectional AC-DC converter (130) connected by a DC bus (150) to a bidirectional DC-DC converter (140), said charger being connected on the one hand to an electric battery (110) and on the other hand to an alternating electrical network (100), said charger (1) being adapted to operate in charging (G2V) and discharging (V2G, V2X) of said battery (110); The device (120) comprising means for determining an operating zone of the bidirectional DC-DC converter (140), chosen from a saturated zone (20, 20') and an unsaturated zone, as a function of the operating mode of the charger (1), in charge or in discharge, as a function of the battery voltage (Vbat) and as a function of the power (P) of the battery; The device (120) comprising means for implementing a set of steps for regulating the voltage of the DC bus (150) comprising: - if the vehicle operates in discharge mode (V2G) and if the DC-DC converter is in a saturated zone, regulation by phase change modulation PSM, - if the vehicle is operating in charge mode (G2V) and if the DC-DC converter is in a saturated zone, the output of the DC-DC bus regulator is added to the power demand in order to carry out a power correction; - if the vehicle operates in charge (G2V) or discharge (V2G) mode and if the DC-DC converter is in an unsaturated zone, regulation of the DC bus by pulse frequency modulation (PFM) including: - A sub-step of calculating (51) a feedforward switching frequency (fO) obtained by inverting the gain as a function of the power of the DC-DC converter (140), the battery voltage (Vbat) and a reference value of the DC bus voltage (Voc ref ) ; - A sub-step of calculating (52) a regulation value of a proportional integral (PI) regulator, a function of the difference between the DC bus voltage and the DC bus reference value; - a sub-step of summing (53) the regulation value calculated with the feedforward switching frequency, so as to cancel the DC bus voltage error; The device (120) also comprising means for implementing a set of steps for regulating the network currents (100) by pulse width modulation (PWM) comprising: - A step of calculating an input parameter to generate reference currents, calculated so that: o If the charger operates in charge mode (G2 V) and if the DC-DC converter is in a saturated zone, the input parameter is the sum (80) of the charger's power demand (P re f) with the regulation value calculated for the DC bus regulation; o Otherwise, the input parameter is the value of the charger power demand (P re f); - A step of generating (71, 81) setpoint currents as a function of the measured phase voltages and the calculated input parameter; and - A current regulation step (82) adapted to define duty cycles (D*) as a function of the setpoint currents; and - A step of regulating (73) the network currents by pulse width modulation (73) as a function of said duty cycles (D*), providing control signals for the bidirectional AC-DC converter (130).

6. Electrical system comprising a bidirectional charger (1) comprising a bidirectional AC-DC converter (130) connected by a DC bus (150) to a bidirectional DC-DC converter (140), said charger being connected on the one hand to an electric battery (110) and on the other hand to an AC electrical network (100), said charger (1) being adapted to operate in charging (G2V) and discharging (V2G, V2X) of said battery (110), the electrical system also comprising a regulation device according to claim 5.

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

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