WO2010136700A2

WO2010136700A2 - System for recharging a battery for powering an electric motor, and vehicle including such a system

Info

Publication number: WO2010136700A2
Application number: PCT/FR2010/050968
Authority: WO
Inventors: Emmanuel Godefroy; Dimitri Olszewski
Original assignee: Peugeot Citroën Automobiles SA
Priority date: 2009-05-25
Filing date: 2010-05-19
Publication date: 2010-12-02
Also published as: FR2945899B1; FR2945899A1; WO2010136700A3

Abstract

The invention relates to a system for recharging batteries for an automobile (1), including: an AC/DC converter (22); an AC electric motor (5) for driving the vehicle and connected to said AC/DC converter (22); a first battery (11) capable of powering or being recharged by the electric motor (5) via the AC/DC converter; a circuit (32) having an interface (31) for connecting to a public power grid and for conveying the current from the public power grid to the connection between the electric motor and the AC/DC converter; and a second battery for powering a grid onboard the vehicle. A step-down DC/DC converter (23) has a high-voltage terminal connected to the first battery (11) and a low-voltage terminal connected to the second battery.

Description

SYSTEM FOR RECHARGING A POWER SUPPLY BATTERY OF AN ELECTRIC MOTOR AND VEHICLE EQUIPPED WITH SUCH A SYSTEM

The invention relates to vehicles with an electric motor, such as electric traction vehicles or so-called hybrid vehicles, further comprising an internal combustion engine.

A hybrid traction vehicle comprises firstly an internal combustion engine and secondly an electric motor powered by a storage battery. Such a vehicle comprises a computer automatically managing the traction mode of the vehicle. When the battery is sufficiently charged, the computer gives priority to electric traction. When the vehicle exceeds a certain speed, the computer gives priority to the thermal traction. When the state of charge of the battery is insufficient, the computer gives priority to the thermal traction to move the vehicle and recharge the battery.

The battery is charged when the vehicle is driven by the engine. In this case, the heat engine drives the electric motor which then operates as a generator and charges the battery. Furthermore, it is also known to recharge the battery when the vehicle is stopped via a power supply network. Recharging by the electrical network thus limits the use of the engine during running. Less use of the engine is particularly advantageous for urban journeys to limit fuel consumption.

[0004] A known vehicle includes a battery charger connectable to the public electricity grid. This charger has an application input of a single-phase alternating voltage, for example 220 V. The charger further includes a single-phase rectifier bridge connected to this input to generate a rectified high voltage. The charger includes on the one hand an isolated DC / DC converter transforming the high voltage into low voltage and on the other hand a non-isolated DC / DC converter transforming the high voltage into another high voltage level. The charger thus has a low voltage output and a high output voltage. The vehicle has a low voltage battery (typically 13V) connected to the low voltage output. The low voltage battery supplies the vehicle's on-board network. The vehicle has high voltage batteries (of the order of 200V) connected to the high voltage output. The high voltage batteries power an electric motor driving the wheels of the vehicle and possibly other high voltage loads. When connected to the public electricity grid, the low voltage battery and the high voltage batteries are recharged. A DC / DC converter with galvanic isolation connects the low voltage network to the high voltage network.

[Ooo5] A diode bridge applies three-phase voltages on stator windings of the electric motor when it operates as a motor.

[0006] The internal combustion engine is selectively coupled to the electric motor when the electric motor is operating as a generator. Via the diode bridge, the electric motor can then recharge the high voltage batteries and the low voltage battery.

Although charging by the power network is performed for a very short life cycle of the vehicle, this circuit must be permanently embedded in the vehicle. Such a charging circuit to handle large electrical power, this circuit has a very large footprint and cost. In addition, the low voltage converter involves an independent and dedicated regulator, in particular to ensure adequate protection of the low voltage circuit. Such a regulator has a very important cost.

[Oooδ] The invention aims to solve one or more of these disadvantages. The invention thus relates to a motor vehicle battery recharging system, comprising an AC / DC converter; an AC motor for driving the vehicle connected to said AC / DC converter; a first battery capable of being supplied or recharged by the electric motor via the AC / DC converter; a circuit having a connection interface to a public electricity grid, conducting the power of the public electricity grid to the connection between the electric motor and the AC / DC converter; a second battery for powering an on-board network of the vehicle.

The charging system further comprises a DC / DC voltage-down converter having a high voltage terminal connected to said first battery and a low voltage terminal connected to the second battery.

[Ooio] According to one variant, the DC / DC converter is controlled so that the voltage level on the low voltage terminal is configurable.

According to another variant, the charging system comprises a further a switch adapted to open the circuit between the connection interface to the public grid and the connection between the electric motor and the converter and a control module able to detect a starting instruction of the vehicle and generating an opening command of the switch when a start command is detected.

According to another variant, said electric motor is a three-phase motor.

According to yet another variant, the AC / DC converter is a bridge operating selectively in inverter or rectifier.

According to another variant, the charging system comprises an internal combustion engine driving the vehicle and a clutch selectively coupling the internal combustion engine to the electric motor, the AC / DC converter being controlled to operate as a rectifier when the internal combustion engine drives the electric motor.

The invention also relates to a motor vehicle, comprising a charging system as defined above.

According to a variant, said connection interface to the public network is accessible from outside the vehicle.

Other features and advantages of the invention will become apparent from the description which is given below, for information only and not limiting, with reference to the accompanying drawings, in which Figure 1 is a representation. schematic of a motor vehicle battery charging system according to an exemplary implementation of the invention, Figure 2 specifies the electrical circuit between the network connection interface and the connection between the electric motor and the converter in the case of a single-phase public electricity network, Figure 3 specifies the electrical circuit between the network connection interface and the connection between the electric motor and the converter in the case of a three-phase public electricity network.

The invention provides a motor vehicle battery charging system. This system is equipped with a rechargeable high voltage battery via the public electricity grid. An AC / DC converter is interposed between an AC electric motor and the high voltage battery. The battery is capable of being supplied or recharged by the electric motor via the converter. A circuit has a connection interface with the public grid and conducts the network current to the connection between the electric motor and the converter. A DC / DC converter is interposed between the high voltage battery and a low voltage battery.

Such a charging system allows to use a pre-existing component to recharge the high voltage battery and the low voltage battery. The number of components, the size, weight and complexity of the electric circuit of the charging system are thus substantially reduced.

Figure 1 shows a battery charging system 1 according to one embodiment of the invention. The charging system 1 comprises an AC electric motor 5. The motor 5 is in this case a three-phase motor. The electric motor 5 is particularly intended to drive the wheels of the vehicle. This motor 5 can be selectively controlled to operate as a motor or generator. U, V and W lines are connected to stator windings of the motor 5. The charging system 1 further comprises an AC / DC converter 22. The converter 22 is controlled by a control circuit 42 to operate either as a rectifier or inverter. The converter 22 is interposed between the electric motor 5 and a DC network. The DC network includes a high voltage portion, including a battery 11. The accumulator battery 1 1 is adapted to be able to power the motor 5 in motor mode, or to accumulate electrical energy when the motor 5 operates as a generator. The DC network also includes a low voltage portion. A DC / DC converter 23 is interposed between the high voltage part and the low voltage part. The low voltage part of the continuous network comprises in particular a battery 12 intended to supply the on-board network, and charges 81 and 82 connected to this on-board network.

An interface 31 is intended to be connected to a single-phase public electricity network. This interface is accessible from outside the vehicle. The interface 31 may be a standardized socket for the public electricity grid. A circuit 32 connects the phases or the phase and the neutral of the electrical network to respective lines U, V and W.

The converter 22 can thus be used to recharge both the high voltage battery 1 1 and the low voltage battery 12 at the stop of the vehicle by connecting the interface 31 on the public power grid. Since the converter 22 retains its initial function of switching from the inverter mode to the rectifier mode during the operation of the vehicle, the recharging of the batteries 1 1 and 12 at a standstill is carried out without the need for a complex, heavy and bulky additional circuit.

The converter 22 may have a structure known in itself to those skilled in the art. The converter 22 may, for example, comprise a bridge having six pairs of diodes and transistors, ie six electronic switches, the switching of the transistors then being controlled by the control circuit 42.

A capacitor may be connected in parallel with the bridge to improve the ripple factor. The converter 22 is controlled by an inverter to transform the direct current supplied by the battery 1 1 AC three-phase current applied on lines U, V, W when a motor 5 is in motor mode. When the motor 5 is in generator mode, or when recharging by the electrical network, the converter

22 is controlled by a rectifier for converting the alternating current supplied by the motor 5 into direct charging current of the batteries 11 and 12.

The converter 23 is preferably galvanically isolated. The converter

23 operates as a step-down between the high voltage part and the lower part voltage of the vehicle's electrical network. The converter 23 may, for example, transform a voltage of the order of 200 V into a voltage of the order of 12 V. The converter 23 may be controlled to configure or regulate the voltage level on the low voltage part of the vehicle electrical network. .

A switch 21 is interconnected between the interface 31 and the lines U, V, W. The switch 21 is intended to selectively open the connection between the interface 31 and these lines. The switch 21 is controlled by a control circuit 41. The control circuit 41 opens the switch when it detects a starting instruction of the vehicle. Thus, the switch 21 is open if the vehicle starts while the interface 31 is inadvertently maintained connected to the public power grid. The switch 21 protects both the public electricity network and the vehicle electrical network. Switch 21 may also include protections. Switch 21 may include a three-contact relay or semiconductors. The control circuit 41 can automatically close the switch when a stopping position of the vehicle is detected and the interface 31 is connected to the public power grid.

In the illustrated charging system, the vehicle drive motor is of the hybrid type. An internal combustion engine 7 can thus be coupled in a manner known per se to the electric motor 5 via a clutch 6. When the internal combustion engine 7 is running, the converter 22 can be controlled in a rectifier mode in order to recharge the batteries 1 1 and 12. The selection of the drive by the electric motor 5 and / or by the internal combustion engine 7 can be carried out in a manner known per se as a function of the charge level of the battery 11 or the conditions of the rolling.

In the example shown, the interface 31 is intended to be connected to a single-phase public electrical network, for example to a voltage of 220 V. Figure 2 specifies the electrical circuit between the interface 31 of the network connection. and the connection between the electric motor 5 and the converter 22, in the case of a single-phase public electricity network. In this configuration, the interface 31 is connected to the switch 21 by a line p intended to be in connection with the phase of the public electricity network and a line n intended to be connected to the neutral of the network electric power. In this configuration again, the switch 21 is connected to each of the lines U, V, W by three separate power lines. Furthermore, provision is made downstream of the switch 21, a capacitor 50 between the unpowered line and the electrical line connected to the phase p of the single-phase network. The capacitor 50 can also be integrated in the switch 21.

The interface 31 may also be adapted to be connected to a three-phase public electrical network, for example a voltage of 380 V. FIG. 3 specifies the electrical circuit between the interface 31 of connection to the network and the connection between the electric motor 5 and the converter 22, in the case of a three-phase public electrical network. In this configuration, the interface 31 is connected to the switch 21 by three separate lines intended to be each connected to a phase of the three-phase public network, this configuration again, the switch 21 is connected by three separate lines to each of lines U, V, W. In this case, there is no need for the capacitor 50.

Claims

A motor vehicle battery charging system (1), comprising an AC / DC converter (22); an AC motor (5) for driving the vehicle connected to said AC / DC converter (22); a first battery (1 1) capable of being fed or recharged by the electric motor (5) via the AC / DC converter; a circuit (32) having a connection interface (31) to a public power grid, conducting power from the utility grid to the connection between the electric motor and the AC / DC converter; a second battery for powering an on-board network of the vehicle; characterized in that it further comprises a step-down DC / DC converter (23) having a high voltage terminal connected to said first battery (1 1) and a low voltage terminal connected to the second battery.

The charging system of claim 1, wherein the DC / DC converter (23) is controlled so that the voltage level on the low voltage terminal is configurable.

3. Recharging system according to claim 1 or 2, further comprising a switch (21) adapted to open the circuit (32) between the connection interface

(31) to the public electricity grid and the connection between the electric motor and the converter; and a control module (41) capable of detecting a start-up setpoint of the vehicle and generating an opening command of the switch (21) when a starting instruction is detected.

4. Refueling system according to any one of the preceding claims, wherein said electric motor (5) is a three-phase motor.

A recharging system according to any one of the preceding claims, wherein the AC / DC converter (22) is a bridge operating selectively in inverter or rectifier.

Recharging system according to claim 5, comprising an internal combustion engine (7) driving the vehicle and a clutch (6) selectively coupling the internal combustion engine to the electric motor (5), the AC / DC converter ( 22) being controlled to operate as a rectifier when the internal combustion engine drives the electric motor.

7. Motor vehicle, comprising a charging system according to any one of the preceding claims.

8. Motor vehicle according to claim 7, wherein said connection interface (31) to the public network is accessible from outside the vehicle.