FR3081266A1 - SYSTEM AND METHOD FOR NON-CONTACT ELECTRIC POWER TRANSFER BETWEEN A DEVICE ATTACHED TO THE GROUND AND A VEHICLE - Google Patents

Abstract

A non-contact power transfer system between a ground fixed power supply device (DISP) comprising a first converter (20) for coupling to a DC voltage source (10) and supplying a first resonant circuit (30) comprising at least one primary coil (L30), and a vehicle (VEH) comprising a second converter (50) for coupling to the onboard power grid (70) and connected to a second resonant circuit (80) comprising at least one secondary coil (L80), said system being able to transfer an electrical power by induction between the two coils forming a magnetic coupler and comprising a first processing unit (UT40) capable of driving the switching cells (CEL21, CEL22, CEL23, CEL24) of the first power supply (20) and a second processing unit (UT90) capable of driving the switching cells (CEL51, CEL52, CEL53, CEL54) of the second power supply (50). Each processing unit is configured to regulate the non-zero phase shift (φE, φS) between the current and the voltage across one of the resonant circuits and to regulate the switching frequency of the switching cells of the power converter supplying the resonant circuit. in order to follow a regulation instruction.

Description

System and method for contactless electrical power transfer between a device fixed to the ground and a vehicle

The present invention relates to the charging of a motor vehicle, in particular the contactless charging of an electric or hybrid vehicle.

It relates more particularly to a system and method for contactless charging of a motor vehicle battery. This is to allow a transfer of energy from the ground to an electric or hybrid vehicle rolling from one or a set of primary coil (s) disposed on the ground, and one or a set of secondary coil (s) on-board in the vehicle and connected to the power network of the vehicle through a conversion stage enabling energy management to be ensured and control of power transmission. Thereafter, in order to simplify the explanations, the contactless charging system comprises a coil in the primary and a coil in the secondary.

When the vehicle is traveling on an electric road with induction power transmission, several primary coils integrated into the road are activated and deactivated successively according to the progress of the vehicle on the road.

In order to be able to transmit energy by induction, it is necessary to magnetize the air gap separating the two coils.

The charging power can range from ten kW to more than one hundred kW.

As the powers used are high with regard to the sizes of coils compatible with a motor vehicle, it is necessary to minimize the constraints imposed on the components of the system, in particular the electrical constraints (voltage and / or current) in the passive components (coils and capacitors of resonant circuits).

Generally a resonant circuit with a high quality factor is used to minimize losses in the system, whether it be those by switching semiconductors or even losses by conduction in these same semiconductors or in resonant circuits.

Several methods of controlling switching power supplies comprising transistors supplying the primary and secondary coils make it possible to minimize the losses by switching of the transistors, in particular a switching mode of switching type with zero voltage known by a person skilled in the art under the terms "Anglosaxons". Zero Voltage Switching »ZVS or soft switching, ie at a frequency higher than the resonance frequency with losses when the transistors are blocked.

In this regard, reference may be made to the document FR3043505 which describes a contactless charging system SYS1 of the battery of a vehicle traveling from the ground comprising a resonant circuit of the series-series type implementing zero voltage switching ZVS at zero phase shift between current and voltage, that is to say that the switching of the transistors is controlled so that the switching takes place when the voltage across the drain and the source and the current at the drain of a transistor for example field effect are zero. Switching losses are very low.

Figure 1 shows the SYS1 system comprising a power supply device DISP1 and a motor vehicle VEH1.

The device DISP1 comprises a source of direct electrical voltage 1 connected to a converter 2 comprising switching cells CEL2a, CEL2b, CEL2c and CEL2d produced from transistors T2 and diodes D2.

The outputs of the converter 2 are connected to a compensated resonant circuit 3 of the series-series type comprising a capacitor C3 connected in series with a coil L3.

The vehicle VEH1 comprises a compensated resonant circuit 4 of the series-series type comprising a capacitor C4 connected in series with a coil L4 connected to a converter 5 comprising switching cells CEL5a, CEL5b, CEL5c and CEL5d produced from transistors T5 and diodes D5.

The outputs of the converter are connected to the terminals of a battery 7. A filtering capacitor 6 is connected to the terminals of the battery 7.

When charging the battery 7, the vehicle VEH1 is placed above the device DISP1 located in the ground so that the coils L3 and L4 are opposite one another so that the electrical power contained in the source 1 of the device DISP1 can be transferred to the battery 7 of the vehicle VEH1. The distance between the two coils can be up to 30 cm.

An axis (A) is defined between the two coils L3 and L4 and is equidistant from each of the coils.

The coils L3 and L4 form a magnetic coupler.

The structures on the one hand of the converter 2 and the resonant circuit 3 and, on the other hand of the converter 5 and the resonant circuit 4, are symmetrical with respect to the axis (A).

Bidirectional power transfer is possible.

In operation, the converters 2 and 5 are controlled so that the phase shifts between current and voltage across the terminals of the resonant circuits 3 and 4 are of zero value, and the switching frequency of cells CEL2a to CEL2d and CEL5a to CEL5d is varied in the case of a synchronous rectification to reach the operating point for the power called up by the load.

The symmetrical structure and the same control of the switching power supplies 2 and 5 make it possible to obtain a voltage across the terminals of circuits 3 and 4 equal to a multiplicative factor.

The command allows switching of the switching power supplies 2 and 5 when the currents across the terminals of circuits 3 and 4 are canceled, and ensures soft switching. The power factors are equal to 1 at the input and at the output, which minimizes the losses.

However, the operating mode of the system requires having low values for the resonant capacitors C3 and C4.

This implies very high voltages to be supported by said capacitors.

For example, for a SYS1 system with a power of 20 kW, the capacitors C3 and C4 must support a high voltage, which can go beyond 4 kV, in particular when the coil L4 of the vehicle is strongly offset from the coil L3 arranged on the ground. This restricts the range of offset values between the coils L4 and L3 in which the transfer of energy between the vehicle VEH1 and the device DISP1 fixed to the ground can take place without damaging the capacitors C3 and C4, that is to say the voltage across the resonant capacitors remains below the threshold voltage of each of the capacitors C3 and C4.

These constraints limit the range of variation of magnetic coupling possible, and therefore the tolerance to off-center between the device on the ground and the vehicle.

Reference may be made to document FR2962264 which describes a contactless charging system using a pulse train taking into account signals from a transmitter device on the ground to automatically detect an adequate position of the vehicle and thus initiate charging. It does not deal with the operation of the system for charging and dialogue during the entire charge is necessary between the device on the ground and the vehicle. This is hardly compatible with an application for charging a rolling vehicle.

Document US2006 / 082323 discloses a conversion stage connected to an inductive power transfer system intended to adapt the voltage of the battery to be charged applied to its terminals. This document does not disclose any battery discharge function and no optimization of the dimensioning of the magnetic coupler.

Document WO2011 / 146661 presents a system of energy transfer by reversible inductive coupling. The object of this document is the detection of foreign objects in the air gap between the two coils forming a magnetic coupler in order to limit the transfer power in this case.

The document US2015 / 244176 describes a symmetrical and bidirectional inductive transfer system. It does not specify the steering of the system.

Document W02010 / 104803 discloses a wireless charging system for electric portable devices allowing bidirectional energy transfer by implementing a coil dedicated to each direction of energy transfer.

The document WO200310531 1 describes a wireless charging system for electric portable devices allowing an exchange of energy between the batteries of two electric portable devices by coupling to an initially transmitting plate.

The charging systems described in these documents do not make it possible to reduce the high voltage or current constraints of the compensated resonant circuit, that is to say the high voltages across the capacitors of the resonant circuits. In addition, the charging systems implement a dialogue between the device on the ground and the mobile device incorporated in the charging system to control the charging voltage at the terminals of the battery throughout the duration of the charging, which is incompatible. for operation with a moving vehicle.

The object of the invention is to overcome these drawbacks.

In view of the above, the invention provides a method of contactless power transfer between a fixed ground power supply device comprising a first power converter coupled to a DC voltage source and to a first resonant circuit comprising a first capacitor, and a vehicle comprising a second power converter coupled to an on-board power network and connected to a second resonant circuit comprising a second capacitor.

According to a characteristic of the method according to the invention, during a power transfer step, the phase shift between the current and the voltage across one of the resonant circuits is regulated and in that the frequency of switching of the switching cells of the other power converter so as to follow a regulation setpoint.

Advantageously, the first and second power converters comprise switching cells each comprising a transistor switching at zero voltage at a determined frequency.

By zero-voltage switching is meant a near-zero voltage relative to the zero-voltage switching type switching mode known to those skilled in the art under the term "Zero Voltage Switching" ZVS or soft switching.

Preferably, the first and second converters are reversible and able to transfer electrical power from the DC voltage source to the on-board power network or from said on-board power network to said DC voltage source.

According to a first embodiment, during the power transfer step, the switching frequency of the first power converter is regulated at a fixed frequency and the phase shift of the second power converter is regulated so that the transmitted power is equal to the target power.

According to a second implementation mode, during the power transfer step, the phase shift of the first power converter is regulated to a fixed value so that the voltage across each of the capacitors is less than their threshold value and the switching frequency of the second power converter is regulated so that the transmitted power is equal to the set power.

According to a third mode of implementation, during the power transfer step, the switching frequency of the second power converter is regulated at a fixed frequency and the phase shift of the first power converter is regulated so that the transmitted power is equal to the target power.

According to a fourth embodiment, during the power transfer step, the phase shift of the second power converter is regulated to a fixed value so that the voltage across each of the capacitors is less than a threshold value and the switching frequency of the first power converter is regulated so that the transmitted power is equal to the set power.

According to a fifth mode of implementation, during the power transfer step, the switching frequency of the first power converter is regulated at a fixed frequency and the phase shift of the second power converter is regulated so as to follow the setpoint of regulation requiring that the voltage across the second resonant circuit is equal to the voltage across the first resonant circuit to within a multiplicative factor.

According to a sixth embodiment, during the power transfer step, the phase shift of the first power converter is regulated to a fixed value so that the voltage across each of the capacitors is less than their threshold value and the switching frequency of the second power converter is regulated so as to follow the regulation instruction imposing that the voltage across the terminals of the second resonant circuit is equal to the voltage across the terminals of the first resonant circuit to within a multiplicative factor.

The invention also relates to a contactless power transfer system between a fixed electrical power supply device on the ground comprising a first converter intended to be coupled to a DC voltage source and supplying a first resonant circuit comprising at least one coil. primary, and a vehicle comprising a second converter intended to be coupled to the on-board power network and connected to a second resonant circuit comprising at least one secondary coil, said system being capable of transferring electrical power by induction between the two coils forming a coupler magnetic and comprising a first processing unit capable of driving the switching cells of the first power supply and a second processing unit capable of driving the switching cells of the second power supply.

According to a characteristic of the system according to the invention, each processing unit is configured to regulate a non-zero phase shift between the current and the voltage across one of the resonant circuits and to regulate the switching frequency of the switching cells of the converter of power supplying the resonant circuit so as to follow a regulation setpoint.

Advantageously, each switching cell comprises a transistor and a capacitor, a first terminal of which is connected to the source of the transistor and a second terminal of which is connected to the drain of the transistor.

According to another characteristic of the system according to the invention, the first and second converters have a symmetrical structure with respect to a median axis separating the primary and secondary coils of the magnetic coupler.

Other objects, characteristics and advantages of the invention will appear on reading the following description, given solely by way of non-limiting example, and made with reference to the appended drawings in which:

- Figure 1, which has already been mentioned, illustrates a charging device according to the prior art;

- Figure 2 is a schematic view of an electric road with energy transmission by induction according to the invention;

- Figure 3 is a schematic view of a contactless charging system according to the invention;

- Figure 4 is a time diagram illustrating a transistor switching sequence over a period;

- Figure 5 is a time diagram illustrating the switching instants of switching cells;

FIG. 6 illustrates a first embodiment of the contactless charging system according to the invention;

FIG. 7 illustrates a second embodiment of the contactless charging system according to the invention;

FIG. 8 illustrates a third embodiment of the contactless charging system according to the invention;

FIG. 9 illustrates a fourth embodiment of the contactless charging system according to the invention;

FIG. 10 illustrates a fifth embodiment of the contactless charging system according to the invention; and

FIG. 11 illustrates a sixth embodiment of the contactless charging system according to the invention.

Reference will firstly be made to FIG. 2 which represents a block diagram of an electric road with transmission of energy by induction in accordance with the invention on which are fixed devices of electrical supply DISP1, DISP2 and DISP3 fixed to the ground and each incorporating at least one primary coil L, and an electric or hybrid vehicle VEH incorporating at least one secondary coil L80 connected to the vehicle power network.

In order to simplify the explanations, it is assumed below that the fixed electrical supply devices incorporate a primary coil L and the vehicle incorporates a secondary coil L80.

The devices DISP1, DISP2 and DISP3 are supplied by a source 10 of direct voltage.

Source 10 can include a reversible DC voltage source, that is, it can supply energy or store energy.

When the electric or hybrid VEH vehicle in motion is located above one of the devices DISP1, DISP2 or DISP3, this is activated and the corresponding coil L is supplied to transmit electrical power to the vehicle VEH, for example as shown here, the DISP2 device powers the VEH vehicle.

When the vehicle has moved a sufficient distance to be above another fixed device, the latter is activated and the previously activated device changes operating mode so as to no longer deliver electrical power to the vehicle VEH.

First, reference is made to FIG. 3 which illustrates an embodiment of a contactless SYS charging system according to the invention.

The SYS system includes a fixed power supply device DISP fixed to the ground similar to the devices DISP1, DISP2 and DISP3 and the vehicle VEH.

The fixed device DISP comprises a first power converter 20 connected to a DC voltage source 10, preferably reversible, and to a first resonant circuit 30, first means for measuring current Mil and a first computer 40.

The converter 20 comprises two arms BR21 and BR22 each comprising two switching cells of identical constitution and two connection terminals B201 and B202. Each of the cells includes a transistor, for example an NMOS type field effect transistor. However, the use of other transistor technologies is also possible, for example bipolar transistors, or transistors with high electron mobility.

Each switching cell further comprises a capacitor, a first terminal of which is connected to the drain of the transistor and a second terminal of which is connected to the source of the transistor and a diode of which the anode is connected to the source and the cathode is connected to the drain of the transistor. .

The arm BR21 comprises two switching cells CEL21 and CEL23 respectively comprising a transistor T21 and T23, a diode D21 and D23, and a capacitor C21 and C23 arranged as described above.

According to another embodiment, each switching cell includes an NMOS transistor comprising a diode mounted in antiparallel to the transistor, the anode of which is connected to the source and the cathode is connected to the drain of the transistor known to those skilled in the art under the Anglo-Saxon name "body diode".

The drain of transistor T21 is connected to terminal B201 and the source of transistor T21 is connected to the drain of transistor T23.

The source of transistor T23 is connected to terminal B202.

The arm BR22 comprises two switching cells CEL22 and CEL24 respectively comprising a transistor T22 and T24, a diode D22 and D24, and a capacitor C22 and C24 arranged as described above.

The drain of transistor T22 is connected to terminal B201 and the source of transistor T22 is connected to the drain of transistor T24.

The source of transistor T24 is connected to terminal B202.

The positive terminal of the voltage source 10 is connected to the terminal B201 and the negative terminal is connected to the terminal B202.

The first resonant circuit 30 comprises a first capacitor C30, a first terminal of which is connected by means Mil to the common node between the source of the transistor T21 and the drain of the transistor T23, and a second terminal is connected to a first terminal d 'a primary coil L30 identical to the coil L. A second terminal of the coil L30 is connected to the common node between the source of the transistor T22 and the drain of the transistor T24.

The transistors T21, T22, T23 and T24 are controlled by first control means MP40 incorporated in the first computer 40.

A current is flowing through the capacitor C30 and a voltage ue is noted at the terminals of the circuit 30. Let (pE be a first phase shift between the current ise and the voltage eu.

The computer 40 includes the control means 40, first wireless communication means MC40 and a first processing unit UT40.

The computer 40 is for example an automobile computer.

The UT40 processing unit is configured to control the MP40 control means according to the instructions received by the MC40 communication means and the MIL measurement means.

For example, the processing unit UT40 is produced from a computer, but it can be any on-board device making it possible to implement the means MP40, MC40 and MIL

The means Mil are configured to measure the value and the sign of the current Îe and to transmit the measured values to the unit UT40.

The processing unit UT40 is further configured to determine the phase shift (pE by measuring the time between the zero crossing (sign change) of the current Îe and the next rising edge of the control signal from cells CEL21 and CEL24.

If the source 10 includes a reversible DC voltage source, the unit UT40 is also configured to determine the maximum power PmaxlO admissible by the source and to draw up a power setpoint PconslO for charging the source 10.

The VEH vehicle comprises a second power converter 50 connected to a filter 60, a power network 70 intended to manage the power supply of the vehicle and comprising a connection terminal of positive polarity and a connection terminal of negative polarity , a second resonant circuit 80, second current measurement means MI2, a second computer 90 and means MB for monitoring the network 70.

The network 70 may include a battery.

The second converter 50 comprises two arms BR51 and BR52 each comprising two switching cells of constitution identical to the switching cells described above and two connection terminals B501 and B502.

The arm BR51 comprises two switching cells CEL51 and CEL53 respectively comprising a transistor T51 and T53, a diode D51 and D53, and a capacitor C51 and C53 arranged as described above.

The drain of transistor T51 is connected to terminal B501 and the source of transistor T51 is connected to the drain of transistor T53.

The source of transistor T53 is connected to terminal B502.

The arm BR52 comprises two switching cells CEL52 and CEL54 respectively comprising a transistor T52 and T54, a diode D52 and D54, and a capacitor C52 and C54 arranged as described above.

The drain of transistor T52 is connected to terminal B501 and the source of transistor T52 is connected to the drain of transistor T54.

The source of transistor T54 is connected to terminal B502.

The filter 60 comprises a capacitor C60, a first terminal of which is connected to the terminal B501 and a second terminal of which is connected to the terminal B502.

The positive terminal of network 70 is connected to terminal B501 and the negative terminal is connected to terminal B502. There is a voltage Vs across the network 70.

The second resonant circuit 80 comprises a second capacitor C80, a first terminal of which is connected via the means MI2 to the common node between the source of the transistor T52 and the drain of the transistor T54, and a second terminal is connected to a first terminal d 'a secondary coil L80 identical to the coil L. A second terminal of the coil L80 is connected to the common node between the source of the transistor T51 and the drain of the transistor T53.

The transistors T51, T52, T33 and T54 are controlled by second control means MP90 incorporated in the second computer 90.

A current is flows through the capacitor C80 and there is a voltage us at the terminals of circuit 80. Let tps be a second phase shift between the current is and the voltage us.

The computer 90 includes the control means MP90, second wireless communication means MC90 and a second processing unit UT90.

The computer 90 is for example an automobile computer. This is any computer that can be loaded into a vehicle.

The UT90 processing unit is configured to control the MP90 control means according to the instructions received by the MC90 communication means and the MI2 measurement means.

For example, the processing unit UT90 is produced from a computer, but it can be any on-board device making it possible to implement the means MP90, MC90 and MI2.

The MI2 means are configured to measure the value and sign of the current is and transmit the measured values to the UT90 unit.

The means MB are configured to receive a power setpoint emitted by the network 70, and to transmit the power setpoint to the unit UT90.

If the network comprises an electrical energy storage means, for example a battery, the means MB are further configured to read the state of the battery, in particular the temperature of the battery, the current and the voltage across the terminals of the drums.

The processing unit UT90 is further configured to determine the phase shift tps by measuring the time between the zero crossing (sign change) of the current is and the next rising edge of the control signal from cells CEL52 and CEL53, determining the maximum power Pmax70 admissible by the network 70 on board the VEH vehicle and develop a power setpoint Pcons70 for supplying the network 70.

The coils L30 and L80 form a magnetic coupler, the value of the coupling coefficient of which depends on the misalignment of the coil L80 with respect to the coil L30, that is to say the vehicle VEH with respect to the DISP device.

The structures on the one hand of the converter 20 and the resonant circuit 30 and, on the other hand of the converter 50 and the resonant circuit 80, are symmetrical with respect to a median axis of the magnetic coupler (M).

The capacitors C21 to C24 and C51 to C54 are of identical capacity, for example 10 nF and support a voltage equal to that of the DC source 10. The diodes D21 to D24 and D51 to D54 are preferably identical, and the transistors T21 to T24 and T51 to T54 are preferably identical.

This symmetrical structure on the one hand of the converter 20 and the resonant circuit 30 and, on the other hand of the converter 50 and the resonant circuit 80 makes it possible to control the converters 20 and 50 symmetrically.

In addition, this symmetrical structure allows a bidirectional power transfer within the SYS system, that is to say that according to the control of the converters 20 and 50, the source 10 can supply the network 70 or if the source 10 comprises a source. reversible DC voltage and the network 70 includes a DC voltage source, for example a battery, it can charge the voltage source 10.

Each processing unit UT40 and UT90 is configured to regulate the phase shift between the current and the voltage across one of the resonant circuits 30 and 80 and regulate the switching frequency of the switching cells of the power converter supplying the resonant circuit of so as to follow a regulation instruction.

In what follows, it is assumed that the source 10 feeds the network 70.

In operation, the transfer of power between the source 10 and the network 70 is regulated by regulating the phase shift (ps when the switching frequency of cells CEL21 to CEL24 is regulated in a fixed manner, by regulating the phase shift φε when the switching frequency of cells CEL51 to CEL54 is regulated in a fixed manner, so as to follow a regulation instruction.

Different modes of implementing the SYS system are described in the following.

The regulation setpoint includes a setpoint power or requires that the voltages across the first and second resonant circuits be equal to a multiplicative factor.

The multiplying factor M1 is equal to the transformation ratio of the magnetic coupler.

The converter 20 operates at an advantageously chosen frequency F20, of period T20, for example, 85 kHz.

The switching cells CEL21 and CEL24 are driven in phase opposition with respect to the cells CEL22 and CEL23, that is to say that when the transistors T21 and T24 are on, the transistors T22 and T23 are blocked.

Likewise, the switching cells CEL51 and CEL54 are driven in phase opposition with respect to the cells CEL52 and CEL53.

Reference is made to FIG. 4 which illustrates over a period T20 the evolution of the current Ie and the voltage Oe according to the state of the transistors T21 to T24.

State 1 designates the on state of the transistor and state 0 designates the off state of the transistor.

Of course, the converter 50 operates in a similar manner.

Reference is made to FIG. 5 which schematically represents at the switching instants INSTC1 and INSTC2 of the period T20 the voltage VT21 between the drain and the source of the transistor T21 and the drain current IT21 at the drain of the transistor T21, and the voltage VT22 between the drain and the source of transistor T22 and the drain current IT21 at the drain of transistor T22.

It is observed that the switching of the transistors T21 and T22 at the instants INSTC1 and INSTC2 takes place when the voltages VT21 and VT22 are zero.

At instant INSTC1 the current Îe charges the capacitors C21 and C24, and the capacitors C22 and C23 discharge.

At instant INSTC2 the current Îe charges the capacitors C22 and C23, and the capacitors C21 and C24 discharge.

The voltage signals between the drain and the source and the intensity signals at the drain of the transistors T23, T24 and T51 to T54 are similar to those of the transistors T21 and T22.

The capacitors C21 to C24 and C51 to C54 are dimensioned so as to ensure smooth switching operation of the transistors. This operation is known to the skilled person under the term "Zero Voltage Switching", ZVS.

The capacitors C21 to C24 and C51 to C54 make it possible to very greatly reduce the losses on blocking of the transistors, while the ignition of the transistors is done at zero voltage at the switching frequency F20 of the transistors by diverting the current in the capacitors C21 to C24 and C51 to C54 during the switching phases of the transistors of the switching power supplies 20 and 50.

Transistors T21 to T24 and T51 to T54 switch at zero voltage at the determined frequency F20.

Reference is made to FIG. 6 which represents a first mode of implementation of the SYS system, in which the computer 90 regulates the transfer of power between the source 10 and the network 70 by adjusting the phase shift tps so that the transferred power enters the DISP device and the VEH vehicle is equal to the set power Pcons70.

In a first step 1, the measurement means MB receive a power instruction emitted by the on-board power network 70 or if the power network 70 comprises a battery, read the parameters of the battery, in particular the temperature, the intensity and the battery voltage, and transmit these values to the processing unit UT90 which in particular determines the maximum permissible current is Imax70 for supplying the network 70 as a function of these values, calculates the maximum charge power Pmax70 admissible by the network 70 and develops a regulation setpoint comprising a setpoint power Pcons70 of a value less than or equal to the power Pmax70.

In a step 2, the unit UT90 sends a charge start signal to the device DISP via the communication means MC90 and controls the cells CEL51 to CEL54 so that the transistors T51 to T54 are blocked.

The converter 50 functions as a diode rectifier.

The communication means MC40 transmit the signal to the processing unit UT40 which, on receipt of the signal, controls the transistors of the switching cells CEL21 to CEL24 at the frequency F20 so that the coil L30 is supplied.

In a power transfer step 3, after the signal has been sent by the means MC90, the unit UT40 regulates the switching frequency of the first power converter 20 at the fixed frequency F20 and the unit UT90 regulates the phase shift tps of the second power converter 50 so that the transmitted power is equal to the set power Pcons70.

At the end of the charge, in step 4, the UT90 unit controls the cells CEL51 to CEL 54 so that tps is equal to 90 °, that is to say that only reactive power is exchanged. The UT40 unit recognizes this phase shift configuration and controls the transistors T21 to T24 so that they are blocked. The charge stops.

During the power transfer step, the power demand of the network 70 can vary, therefore the power Pcons70 varies during the power transfer step. At all times the UT90 unit determines the power Pcons70 and adjusts the phase shift tps so that the transferred power is equal to the power Pcons70.

Referring to FIG. 7 which represents a second mode of implementation of the SYS system, in which the computer 40 regulates the transfer of power between the source 10 and the on-board power network 70 by adjusting the switching frequency of the converter 50 so that the transferred power is equal to the set power Pcons70.

In a first step 10 similar to step 1, the measurement means MB receive a power instruction emitted by the on-board power network 70 or if the power network 70 comprises a battery, read the parameters of the battery, in particular the temperature, current and voltage of the battery, and transmit these values to the processing unit UT90 which in particular determines the maximum permissible current is Imax70 of supply from the network 70 based on these values, calculates the maximum charging power Pmax70 admissible by the network 70 and develops a regulation setpoint comprising a setpoint power Pcons70 of value less than or equal to the power Pmax70.

In a step 11 analogous to step 2, the unit UT90 sends a start of charge signal to the device DISP via the communication means MC90 and drives the cells CEL51 to CEL54 so that the transistors T51 to T54 are blocked.

The converter 50 functions as a diode rectifier.

The communication means MC40 transmit the signal to the processing unit UT40 which, on receipt of the signal, controls the transistors of the switching cells CEL21 to CEL24 at the frequency F20 so that the coil L30 is supplied.

In a power transfer step 12, after the signal has been sent by the means MC90, the unit UT40 regulates the phase shift φε of the first power converter to a fixed value so that the voltage across each of the capacitors of the circuits resonants 30 and 80 is less than their threshold value (maximum voltage supported by the capacitors) and the unit UT90 regulates the switching frequency of the second power converter so that the transmitted power is equal to the set power Pcons70.

During this step, the converter 20 operates at the same frequency as the converter 50.

At the end of the charge, in step 13 analogous to step 4 described above, the unit UT90 controls the cells CEL51 to CEL54 so that φε is equal to 90 °, that is to say that only reactive power is exchanged. The UT40 unit recognizes this phase shift configuration and controls the transistors T21 to T24 so that they are blocked. The charge stops.

During the power transfer step, the power demand of the network 70 can vary, therefore the power Pcons70 varies during the power transfer step. At all times, the unit UT90 determines the power Pcons70 and adjusts the switching of the transistors CEL51 to CEL 54 so that the load power is equal to the power Pcons70.

Reference is made to FIG. 8 which represents a third mode of implementation of the SYS system, in which the computer 40 regulates the transfer of power between the source 10 and the power network 70 by adjusting the phase shift (pE so that the transferred power is equal to the set power Pcons70.

In a first step 20 analogous to step 1, the measurement means MB receive a power instruction sent by the on-board power network 70 or if the power network 70 comprises a battery, read the parameters of the battery, in particular the temperature, current and voltage of the battery, and transmit these values to the processing unit UT90 which in particular determines the maximum permissible current is Imax70 of supply from the network 70 based on these values, calculates the maximum charging power Pmax70 admissible by the network 70 and develops a regulation setpoint comprising a setpoint power Pcons70 of value less than or equal to the power Pmax70.

In a step 21 the unit UT90 sends a charge start signal comprising the power setpoint Pcons70 to the device DISP via the communication means MC90 and controls the cells CEL51 to CEL54 so that the transistors T51 to T54 are blocked .

The converter 50 functions as a diode rectifier.

The MC40 communication means transmit the signal to the processing unit UT40.

In a power transfer step 22, the unit UT90 regulates the switching frequency of the second power converter 50 at a fixed frequency F20 and the unit UT40 regulates the phase shift φε of the first power converter 20 so that the transmitted power is equal to the set power Pcons70.

At the end of the charge, in step 23 similar to step 4 described above, the unit UT90 controls the cells CEL51 to CEL 54 so that φε is equal to 90 °, that is to say that only reactive power is exchanged. The UT40 unit recognizes this phase shift configuration and controls the transistors T21 to T24 so that they are blocked. The charge stops.

During the power transfer step, the power demand of the network 70 can vary, therefore the power Pcons70 varies. At each instant of the charge, the UT90 unit determines the power Pcons70 and sends the updated Pcons70 setpoint to the unit UT40. This information is transmitted at regular intervals, for example every 100 milliseconds by the VEH vehicle to the DISP device.

Reference is made to FIG. 9 which represents a fourth embodiment of the SYS system, in which the computer 40 regulates the transfer of power between the source 10 and the power network 70 by adjusting the switching frequency of the converter 20 of so that the transferred power is equal to a set power Pcons70.

In a first step 30 analogous to step 1, the measurement means MB receive a power instruction sent by the on-board power network 70 or if the power network 70 comprises a battery, read the parameters of the battery, in particular the temperature, current and voltage of the battery, and transmit these values to the processing unit UT90 which in particular determines the maximum permissible current is Imax70 of supply from the network 70 based on these values, calculates the maximum charging power Pmax70 admissible by the network 70 and develops a regulation setpoint comprising a setpoint power Pcons70 of value less than or equal to the power Pmax70.

In a step 31 similar to step 21, the unit UT90 sends a charge start signal comprising the power setpoint Pcons70 to the device DISP via the communication means MC90 and controls the cells CEL51 to CEL54 so that transistors T51 to T54 are blocked.

The converter 50 functions as a diode rectifier.

The MC40 communication means transmit the signal to the processing unit UT40.

In a power transfer step 32, the unit UT90 regulates the phase shift tps of the second power converter 50 to a fixed value so that the voltage across each of the capacitors C30 and C80 is less than their threshold value and l the unit UT40 regulates the switching frequency of the first power converter 20 so that the transmitted power is equal to the reference power Pcons70.

At the end of the charge, in step 33 similar to step 4 described above, the unit UT90 controls the cells CEL51 to CEL 54 so that tps is equal to 90 °, that is to say that only reactive power is exchanged. The UT40 unit recognizes this phase shift configuration and controls the transistors T21 to T24 so that they are blocked. The charge stops.

During the power transfer step, the power demand of the network 70 can vary, therefore the power Pcons70 varies. At each instant of the charge, the UT90 unit determines the power Pcons70 and sends the updated Pcons70 setpoint to the unit UT40. This information is transmitted at regular intervals, for example every 100 milliseconds by the VEH vehicle to the DISP device.

Reference is made to FIG. 10 which represents a fifth mode of implementation of the SYS system, in which the computer 90 regulates the transfer of power between the source 10 and the network 70 by adjusting the phase shift tps so that the voltages ue and us are equal to the multiplicative factor MI, or else us is equal to a predetermined value.

In a first step 40, the processing unit UT90 receives the value of the voltage ue via the means MC40 and MC90 equal to the value of the voltage of the source 10.

In a step 41, the unit UT90 sends a charge start signal to the device DISP comprising the voltage value of the source 10 equal to ue via the communication means MC90 and controls the cells CEL51 to CEL54 so that transistors T51 to T54 are blocked.

The converter 50 operates like a conventional diode rectifier.

The MC40 communication means transmit the signal to the processing unit UT40 which, on reception of the signal, controls the transistors of the switching cells CEL21 to CEL24 at the frequency F20 so that the coil L30 is supplied.

In a power transfer step 42, after the signal has been transmitted by the means MC90, the unit UT40 regulates the switching frequency of the first power converter 20 at the frequency

F20 fixed and the unit UT90 regulates the phase shift (ps of the second power converter 50 so as to follow the regulation instruction imposing that the voltage ns at the terminals of the second resonant circuit 80 is equal to the voltage oe at the terminals of the first resonant circuit 30 to the nearest multiplying factor M.

In this stage, the phase shift (pE is equal to the phase shift (ps to a tolerance close to the offset between the circuits 30 and 80 and the switching frequency of cells CEL51 to CEL 54 is equal to the frequency F20.

At the end of the charge, in step 43 analogous to step 4 described above, the unit UT90 controls the cells CEL51 to CEL 54 so that (ps is equal to 90 °, that is to say that only reactive power is exchanged. The UT40 unit recognizes this phase shift configuration and controls the transistors T21 to T24 so that they are blocked. The charge stops.

Reference is made to FIG. 11 which represents a sixth mode of implementation of the SYS system, in which the computer 90 regulates the transfer of power between the source 10 and the on-board power network 70 by adjusting the switching frequency of the converter 50 so that the voltages oe and ns are equal to the nearest multiplicative ratio Ml.

In a first step 50 analogous to step 40 described above, the processing unit UT90 receives by means of the means MC40 and MC90 the value of the voltage of the source 10 which is equal to the voltage oe.

In a step 51 analogous to step 41, the unit UT90 sends a charge start signal to the device DISP comprising the voltage value of the source 10 equal to the value of the voltage oe via the communication means MC90 and drives cells CEL51 to CEL54 so that transistors T51 to T54 are blocked.

The converter 50 operates like a conventional diode rectifier.

The MC90 communication means transmit the signal to the processing unit UT90 which, on receipt of the signal, controls the transistors of the switching cells CEL51 to CEL54 at the frequency F20 so that the coil L80 is supplied.

In a power transfer step 52, after the signal has been sent by the means MC90, the unit UT40 regulates the phase shift (pE of the first power converter 20 to a fixed value so that the voltage across each of the capacitors C30 and C80 is less than their threshold value and the unit UT90 regulates the switching frequency of the second power converter 50 so as to follow the regulation instruction imposing that the voltage ns across the terminals of the second resonant circuit 80 is equal to the voltage oe across the first resonant circuit 30 to the nearest multiplicative factor M.

At the end of the charge, in step 53 similar to step 4 described above, the unit UT90 controls the cells CEL51 to CEL54 so that tps is equal to 90 °, that is to say that only reactive power is exchanged. The UT40 unit recognizes this phase shift configuration and controls the transistors T21 to T24 so that they are blocked. The charge stops.

Depending on the mode of implementation, the imposed phase shift and frequency values vary within a respectively phase shift or frequency range in which the switching of the transistors is carried out at zero voltage and in ZVS mode.

The parameters of the resonant circuits 30 and 80 and the frequency F20 are chosen so that, according to the value of the multiplicative ratio M1, the voltage across the terminals of the capacitors C30 and C80 are less than their threshold voltage.

The transfer of power between the DISP device and the VEH vehicle takes place with phase shifts which can be non-zero and which vary according to the value of the coupling coefficient, that is to say according to the offset of the VEH vehicle with respect to to the DISP device on the ground.

Non-harmful phase shifts reduce the voltage across the capacitors of the resonant circuits by increasing the capacitance of the capacitors and reducing the impedance of the inductances in the resonant circuits. The range of variation of the switching frequency can be reduced to ensure copying and to choose the frequency F20.

The voltages are now distributed between the resonant capacitors and the transistors.

Non-harmful phase shifts do not compensate for all of the reactive power of the resonant circuits.

The symmetry of the structure of the converters as well as the use of the capacitors connected in parallel with the transistors allow operation in ZVS mode and soft switching over the entire operating range of the SYS system despite phase-shifted signals.

Consequently, the energy efficiency of the transfer of power between the source 10 disposed on the ground and the battery 70 of the vehicle VEH is improved and the radiated electromagnetic spectrum is very reduced.

In addition, due to the symmetry of the converters, energy transfer from the VEH vehicle to the DISP device is possible.

There is no permanent dialogue between the DISP device and the VEH vehicle, which facilitates the charging of the traveling VEH vehicle where great dynamic responsiveness is required. According to the modes of implementation described above, only an exchange between the units UT40 and UT90 is necessary before the start of the charge or a punctual exchange at each update of the power setpoint is necessary.

Advantageously, in the first four modes of implementation described above, the power transfer is regulated according to the power demand of the network 70. It is not necessary to add an additional power converter to regulate the power supplied by the converter 50.

In the fifth and sixth embodiments described above, the phase shift of the first converter is equal to the phase shift of the second converter. Consequently, the output voltage of the converter 50 varies little and facilitates the production of a DC / DC voltage converter connected at the output of the converter 50.

According to another embodiment of the resonant circuits 30 and 80, the capacitor and the inductor can be connected in parallel or can comprise one or more capacitors and inductors connected together. It will be necessary to ensure that the structure of the resonant circuits 30 and 80 is identical, that is to say that in the case of a resonant circuit 30 comprising a capacitor connected in parallel to an inductor, the resonant circuit 80 comprises a capacitor connected in parallel to an inductor.

In addition, zero voltage switching makes it possible to limit electromagnetic emissions.

According to other embodiments, the DC voltage source 10 comprises a reversible DC voltage source.

In these embodiments, the transfer of electrical power can take place bidirectionally between the DC voltage source 10 and the on-board power network 70.

The SYS system can also transfer electrical power from the network 70 to the source 10 comprising a reversible DC voltage source by regulating the power transfer according to one of the first four modes of implementation described above in which the unit 40 determines the maximum load power admissible by the source 10 and develops the regulation setpoint comprising a setpoint power less than or equal to the maximum power admissible by the source 10 or according to one of the fifth and sixth embodiments described previously in which the unit UT40 regulates the converter 20 so that the voltage oe across the first resonant circuit 30 is equal to the voltage ns across the second resonant circuit 80 to within a multiplicative factor.

Claims (12)

1. A method of contactless power transfer between a fixed ground power supply device (DISP) comprising a first power converter (20) coupled to a source (10) of direct voltage and to a first resonant circuit (30) comprising a first capacitor (C30), and a vehicle (VEH) comprising a second power converter (50) coupled to an on-board power network (70) and connected to a second resonant circuit (80) comprising a second capacitor (C80) , characterized in that during a power transfer step (3, 12, 22, 32, 42, 52) a non-zero phase shift (φε, (ps) is regulated between the current and the voltage (υε, us) at the terminals of one of the resonant circuits and in that the switching frequency of the switching cells of the other power converter is regulated so as to follow a regulation setpoint. 2. Method according to claim 1, in which the first and second power converters comprise switching cells (CEL21, CEL22, CEL23, CEL24, CEL51, CEL52, CEL53, CEL 54) each comprising a transistor (T21, T22, T23 , T24, T51, T52, T53, T54) switching at zero voltage at a determined frequency (F20). 3. Method according to one of claims 1 and 2, wherein the first and second converters are reversible and capable of transferring electrical power from the source (10) of direct voltage to the on-board power network or from said power network on board to said DC voltage source. 4. The method of claim 3, wherein during the power transfer step (3), the switching frequency of the first power converter (20) is regulated at a fixed frequency (F20) and the phase shift (cps) is regulated. ) of the second power converter (50) so that the transmitted power is equal to the set power (Pcons70). 5. Method according to claim 3, wherein during the power transfer step (12), the phase shift (çe) of the first power converter (20) is regulated to a fixed value so that the voltage across each capacitors (C30, C80) is less than their threshold value and the switching frequency of the second power converter is regulated so that the transmitted power is equal to the set power (Pcons70). 6. Method according to claim 3, wherein during the power transfer step (22), the switching frequency of the second power converter (50) is regulated at a fixed frequency (F20) and the phase shift is regulated (çe ) of the first power converter (20) so that the transmitted power is equal to the set power (Pcons70). 7. The method of claim 3, wherein during the power transfer step (32), the phase shift (cps) of the second power converter (50) is regulated to a fixed value so that the voltage across each capacitors (C30, C80) is less than their threshold value and the switching frequency of the first power converter (20) is regulated so that the transmitted power is equal to the reference power (Pcons70). 8. The method of claim 3, wherein during the power transfer step (42), the switching frequency of the first power converter (20) is regulated at a fixed frequency (F20) and the phase shift (cps) is regulated. ) of the second power converter (50) so as to follow the regulation instruction imposing that the voltage (ns) across the second resonant circuit (80) is equal to the voltage (de) across the first resonant circuit (30) to within a multiplicative factor (Ml). 9. The method of claim 3, wherein during the power transfer step (52), the phase shift (φε) of the first power converter (20) is regulated to a fixed value so that the voltage across each capacitors (C30, C80) is less than their threshold value and the switching frequency of the second power converter (50) is regulated so as to follow the regulation instruction imposing that the voltage (us) at the terminals of the second resonant circuit (80) is equal to the voltage (ue) at the terminals of the first resonant circuit (30) to a multiplicative factor (Ml). 10. Contactless power transfer system between a fixed ground power supply device (DISP) comprising a first converter (20) intended to be coupled to a DC voltage source (10) and supplying a first resonant circuit (30 ) comprising at least one primary coil (L30), and a vehicle (VEH) comprising a second converter (50) intended to be coupled to the on-board power network (70) and connected to a second resonant circuit (80) comprising at least one secondary coil (L80), said system being capable of transferring electrical power by induction between the two coils forming a magnetic coupler and comprising a first processing unit (UT40) capable of driving the switching cells (CEL21, CEL22, CEL23, CEL24 ) of the first power supply (20) and a second processing unit (UT90) capable of driving the switching cells (CEL51, CEL52, CEL53, CEL 54) of the second power supply (50 ), characterized in that each processing unit is configured to regulate a non-zero phase shift (φε, (ps) between the current and the voltage across one of the resonant circuits and regulate the switching frequency of the switching cells of the power converter supplying the resonant circuit so as to follow a regulation setpoint. 11. The system as claimed in claim 10, in which each switching cell (CEL21, CEL22, CEL23, CEL24, CEL51, CEL52, CEL53, CEL 54) comprises a transistor (T21, T22, T23, T24, T51, T52, T53, T54) and a capacitor (C21, C22, C23, C24, C51, C52, C53, C54), a first terminal of which is connected to the source of the transistor and a second terminal of which is connected to the drain of the transistor. 12. System according to one of claims 10 to 11, wherein the first and second converters have a symmetrical structure with respect to a median axis (M) separating the primary coils and secondary coils (L30, L80) of the magnetic coupler.