FR3044177A1 - BATTERY CHARGER ON BOARD IN A MOTOR VEHICLE EQUIPPED WITH AT LEAST ONE ELECTRIC MOTOR - Google Patents

Abstract

On-board battery charger in a motor vehicle having at least one electric motor, the charger comprising an input filter (2), a rectifier (3), the inductances of the electric machine (4), an inverter (5) , the charger being connected to a power supply network (1) via the input filter (2), and to a battery (6) via the inverter (5). The charger comprises a switching device (7) arranged between the power supply network (1) and the input filter (2), upstream of the rectifier (3), the switching device (7) comprising a device section (8), a current sensing element (9), and a control member (10), the control member (10) being adapted to control the disconnecting member (8) according to minus a current measurement of the current sensing element (9) and at least one current threshold.

Description

On-board battery charger in a motor vehicle having at least one electric motor. The technical field of the invention is battery chargers embedded in motor vehicles, and more specifically such chargers without galvanic isolation between the battery and the power supply network.

The topologies of chargers without galvanic isolation make it possible to charge the batteries on a single-phase or three-phase network without isolation transformer.

Single-phase or three-phase power systems typically include Type A or Type B circuit breakers to protect the user in the event of a load circuit failure that may lead to a voltage build-up across the chassis. These circuit breakers detect and cut currents with a DC component.

Moreover, the state of the art relating to charging stations at the global level shows that, in some countries, an adequate level of differential circuit breaker is not used in or upstream of the charging stations used to recharge the charging stations. vehicles with an on-board charger with this kind of topology.

The document FR2987515 describes an on-board charger for an electric or hybrid vehicle, comprising means for measuring a DC component of a leakage current, means for comparing this measurement with a minimum threshold, and means for breaking the load. of the vehicle, or of degraded mode of this charge, when this threshold is crossed. Cutting the load uses the opening of the charger's rectifier switches.

Such a charger does not allow a fault current failure by the charger switches, unsuited to also protect the customer in case of currents greater than 100 A. Fault currents up to several thousand amp transiently, these switches may have a failure mode induced by the uncontrolled short-circuit current.

The document EP2595170 describes a power cut-off system in particular for charging an electric vehicle, the system being provided with a transformer making it possible to analyze different levels of leakage current. Times are associated with each threshold exceeded and can cut off the power in case of leakage current dangerous to the user. Contactors are used but this document does not mention polarity for these contactors or fuses. The system described comprises only an electrically controlled circuit, the breaking capacity of which is not suitable for high currents greater than 100 A.

There is therefore a need for an on-board charger of a motor vehicle capable of interrupting the circulation of short-circuit currents between two phases of power supply.

An object of the invention is a battery charger embedded in a motor vehicle equipped with at least one electric motor, the charger comprising an input filter, a rectifier, the inductances of the electric motor, an inverter, the charger being connected to a power supply network via the input filter, and to a battery via the inverter.

The charger comprises a cutoff member disposed between the power supply network and the input filter upstream of the rectifier. The cut-off member comprises a disconnecting member, a current sensing element, and a control member, the control member being able to control the disconnecting member as a function of at least one current measurement of the current. current sensing element and at least one current threshold. The current sensing element may comprise a sensor capable of determining a common mode current, a sensor capable of determining an earth current and at least one sensor capable of determining at least one differential current. The disconnecting member may comprise at least one fuse or magnetothermic circuit breaker. The disconnecting member may comprise at least one input contactor capable of interrupting a direct current under direct voltage and an alternating current under AC voltage. The disconnecting member may comprise at least one input contactor able to interrupt an alternating current under AC voltage.

The charger may include battery switches capable of decoupling the battery from the charger based on comparing at least one differential current measurement to a threshold.

The input contactors of the disconnecting member may be polarized contactors with a preferred DC cut-off direction. The disconnecting member may comprise at least one precharging branch connected in parallel with an input contactor, each preloading branch comprising a relay and a resistor connected in series, the preloading relays being able to be closed beforehand. closing the input contactors so as to limit the current initially admitted in the charger. Other objects, features and advantages of the invention will become apparent on reading the following description, given solely by way of nonlimiting example and with reference to the appended drawings in which: FIG. 1 illustrates the main elements of a battery charger installed in a motor vehicle, and - Figure 2 illustrates the main elements of a cut-off device integrated into a battery charger on board a motor vehicle, and - Figure 3 illustrates the main elements of a charger. embedded battery in a motor vehicle according to a second embodiment.

FIG. 1 illustrates a battery charger embedded in a motor vehicle, comprising an input filter 2, a rectifier 3, the inductances of the electric machine 4, an inverter 5 and a battery 6.

A three-phase power supply network 1 is connected to the input filter 2.

The input filter 2 comprises a first capacitor C1 connected by an armature to the first phase of the three-phase supply network, a second capacitor C2 connected by an armature to the second phase of the three-phase supply network, a third connected capacitor C3. by an armature in the third phase of the three-phase supply network, the other armatures of the capacitors C1, C2, C3 being connected together.

The rectifier 3 comprises three input phases each connected to the corresponding phase of the power supply network via the input filter 2.

The first phase is connected to a terminal of a third switch 13 and to the cathode of a sixth diode D6, the anode of a third diode D3 being connected to the other terminal of the third switch 13.

Similarly, the second phase is connected to a terminal of a first switch II and to the cathode of a fourth diode D4, the anode of a first diode DI being connected to the other terminal of the first switch II.

Finally, the third phase is connected to a terminal of a second switch 12 and to the cathode of a fifth diode D5, the anode of a second diode D2 being connected to the other terminal of the second switch 12.

The cathode of the first diode D1, the cathode of the second diode D2 and the cathode of the third diode D3 are connected together to a first output of the rectifier. The anode of the fourth diode D4 is connected to a terminal of a fourth switch 14. The anode of the fifth diode D5 is connected to a terminal of a fifth switch 15. The anode of the sixth diode D6 is connected to a terminal of a sixth switch 16. The other terminals of the fourth switch 14, the fifth switch 15 and the sixth switch 16 are connected together to a second output of the rectifier.

The first output of the rectifier is connected to the three inductors L1, L2, L3 of the three-phase electric motor.

The first phase of the three-phase motor including the first inductor L1 is connected to a first phase of the inverter 5.

The second phase of the three-phase motor comprising the second inductor L2 is connected to a second phase of the inverter 5.

The third phase of the three-phase motor comprising the third inductor L3 is connected to a third phase of the inverter 5.

The first phase of the inverter 5 is connected to the anode of a first diode DO1 and to a terminal of a first switch 101, as well as to the cathode of a second diode D02 and to a terminal of a second switch 102. The first switch 101 and the first diode DO1 are connected in parallel. The second switch 102 and the second diode D02 are also connected in parallel.

Similarly, the second phase of the inverter is connected to the anode of a third diode D03 and to a terminal of a third switch 103, and to the cathode of a fourth diode D04 and to a terminal a fourth switch 104. The third switch 103 and the third diode D03 are connected in parallel. The fourth switch 104 and the fourth diode D04 are also connected in parallel.

Finally, the third phase of the inverter is connected to the anode of a fifth diode D05 and to a terminal of a fifth switch 105, and to the cathode of a sixth diode D06 and to a terminal of a sixth switch 106. The fifth switch 105 and the fifth diode D05 are connected in parallel. The sixth switch 106 and the sixth diode D06 are also connected in parallel.

The cathode of the first diode DO1, the other terminal of the first switch 101, the cathode of the third diode D03, the other terminal of the third switch 103, the cathode of the fifth diode D05 and the other terminal of the fifth switch 105 are connected together to a first output of the inverter. The anode of the second diode D02, the other terminal of the second switch 102, the anode of the fourth diode D04, the other terminal of the fourth switch 104, the anode of the sixth diode D06 and the other terminal of the sixth switch 106 are connected together with the second output of the rectifier 3 to a second output of the inverter 5.

The outputs of the inverter 5 are connected to the terminals of a battery 6.

In FIG. 1, it can be seen that a cut-off device 7 is arranged between the power supply network 1 and the input filter 2, upstream of the rectifier 3.

FIG. 2 illustrates in more detail the structure of the cut-off member 7. The cut-off member 7 comprises a cut-off member 8, a current detection member 9, and a control member 10. The cut-off member 8 comprises at least one contactor 8a, 8b, 8c, 8d capable of interrupting a direct current under DC voltage and / or alternating current under AC voltage, and at least one fuse or magnetothermal circuit breaker 8e, 8f, 8g, 8h. The disconnector comprises a contactor and a fuse / circuit breaker per power supply phase. Thus for a two-phase power supply, the disconnector comprises two contactors and two fuses / circuit breakers. For a three-phase supply with neutral, as shown in Figure 2, the disconnector comprises four contactors and four fuses / circuit breakers. The current sensing element 9 comprises a sensor able to determine a common mode current 9a and sensors able to determine the differential currents 9c, 9d, 9e, 9f. The sensor 9a can also be replaced by a sensor capable of determining a ground current 9b. The control member 10 is able to control the contactors 8a, 8b, 8c, 8d input of the disconnector 8 according to the measurements received from the sensors 9a, 9b, 9c, 9d, 9e, 9f of the current sensing element 9.

The contactors and the fuses are sized according to the failure currents that the breaking device 8 must be able to interrupt.

Thus, the fuses are sized with a current opening template less than the contactor cutout template. For example, the contactors are dimensioned to cut a component in current and DC voltage operating effectively for currents below 400 A, and the fuses are sized to cut currents greater than 300A. The contactor with DC breaking capacity is in both directions or in one direction of current. The fuses are also dimensioned so that, for currents of amplitude greater than the breaking current of the contactors, the opening time of the fuses is less than 200 ms.

The contactors are dimensioned with an AC and DC opening mask so that the sum of the detection delay and the opening delay is less than 200ms for currents of amplitude less than the breaking current of the contactors.

According to a particular embodiment, the contactors of the disconnector 8 are single direction DC polarized contactors.

A polarized contactor with a preferred continuous DC cutoff direction is a contactor used to cut the AC component of a current as well as the DC component when it corresponds to the preferred cutoff direction.

In other words, these contactors are biased in a preferred current direction to be able to open a circuit traversed by a differential mode current comprising a DC component in voltage and current.

Applied to the sectioning member 8, the polarized contactors with a preferred cut-off direction are positioned on each phase in the same direction of polarization. Such a configuration makes it possible to interrupt an undesirable current, for example a short-circuit, flowing between two phases by the opening of a single contactor.

For example, referring to Figure 2, a short circuit current with DC component flowing from the first phase to the second phase can be stopped by the opening of the contactor 8b disposed on the second phase. Once the current is canceled, it controls the opening of the contactor 8a of the first phase.

According to another embodiment illustrated in FIG. 3, the battery charger comprises a control means 11 of the rectifier, a control and monitoring means 12 of the battery able to communicate together via a CAN network 13 In this embodiment, the battery charger is also provided with a breaking device 7 and battery contactors 14a, 14b able to decouple the battery 6 of the inverter 5 from the battery charger and able to be controlled by the control and monitoring means 12 of the battery.

Thus, the second embodiment comprises input contactors 8a, 8b, 8c, 8d capable of interrupting only an alternating current exceeding a predetermined threshold for each of the supply phases in a manner similar to the first embodiment. The fuses make it possible to interrupt the very strong currents which can put the contactors 8a, 8b, 8c, 8d of entry in default.

However, the breaking of the DC currents is ensured by the contactors 14a, 14b of battery. The contactors 4a, 14b are controlled by the control and monitoring means 12 of the battery according to a control signal received from a comparator of the value of at least one differential current at a threshold.

The comparator of the differential currents emits a control signal depending on the result of the comparison to the control and monitoring means 12 of the battery via a dedicated link or via the CAN bus.

In this embodiment, the contactors are much more compact. The control of the contactors is coordinated with the battery contactors which allow to disconnect the battery 6 at high voltage.

This coordinated opening of these actuators makes it possible to greatly reduce the size, the price and the volume of the contactors of the breaking device 7.

This second embodiment coordinates the contactors 8a, 8b, 8c, 8d input fuses whose size is judiciously chosen. Thus, the input contactors 8a, 8b, 8c, 8d are capable of opening the currents up to a certain value (equal to their breaking capacity). In case of a fault inducing very strong currents, the opening takes place by the fuses.

In addition to the embodiments described above, each power supply phase can comprise, at the level of the cut-off device 7, a precharging branch comprising, connected in series, a relay and a resistor, the precharging branch being connected in parallel with the corresponding contactor 8a, 8b, 8c, 8d.

At start-up, the input contactors 8a, 8b, 8c, 8d are open. When authorizing connection to the power supply, the preload contactors are first closed. The current is then limited by the precharging resistors. At the end of a first delay (typically equal to one second), the input contactors 8a, 8b, 8c, 8d are also closed. After a second delay (typically equal to 0.1 seconds), the preload contactors are open

Claims (8)

1. On-board battery charger in a motor vehicle equipped with at least one electric motor, the charger comprising an input filter (2), a rectifier (3), the inductances of the electric motor (4), an inverter (5). ), the charger being connected to a power supply network (1) via the input filter (2), and to a battery (6) via the inverter (5), characterized by the fact that it comprises a cut-off member (7) arranged between the power supply network (1) and the input filter (2) upstream of the rectifier (3), the breaking device (7) comprising a disconnecting member (8), a current sensing member (9), and a control member (10), the control member (10) being adapted to control the disconnecting member (8) as a function of at least one current measurement of the current sensing element (9) and at least one current threshold. 2. The charger of claim 1, wherein the current sensing element (9) comprises a sensor capable of determining a common mode current (9a), a sensor capable of determining a ground current (9b) and at least one a sensor capable of determining at least one differential current (9c, 9d, 9e, 9f). 3. Charger according to any one of the preceding claims, wherein the disconnecting member (8) comprises at least one fuse or magnetothermic circuit breaker (8e, 8f, 8g, 8h). 4. The charger of claim 3, wherein the disconnecting member (8) comprises at least one input contactor (8a, 8b, 8c, 8d) capable of interrupting a direct current under direct voltage and an alternating current under voltage. alternative. 5. The charger of claim 3, wherein the disconnecting member (8) comprises at least one input contactor (8a, 8b, 8c, 8d) capable of interrupting an alternating current under AC voltage. 6. The charger of claim 5 together claim 2, comprising battery contacts (14a, 14b) adapted to decouple the battery from the charger based on the comparison of at least one differential current measurement at a threshold. 7. Charger according to any one of claims 4 or 5, wherein the contactors (8a, 8b, 8c, 8d) of the input of the disconnector member (8) are polarized contactors with a preferred cut-off direction in component keep on going. 8. A charger according to any one of the preceding claims, wherein the disconnecting member (8) comprises at least one preload branch connected in parallel with an input contactor (8a, 8b, 8c, 8d), each preloading branch comprising a relay and a resistor connected in series, the preload relays being able to be closed prior to the closing of the input contactors (8a, 8b, 8c, 8d) so as to limit the current initially admitted into the charger.