VEHICLES OR THE LIKE

Technical Field

The present invention relates to an appliance for recharging batteries of electric vehicles or the like.

Background Art

As is well known, electric vehicles exploit, for ground propulsion, the conversion of part of the chemical energy stored in one or more batteries (so- called “electric vehicle batteries”, EVBs) into electrical energy and the subsequent transfer of the latter to an electric motor.

In order to enable periodic recharging of batteries, electric vehicles are provided with special appliances, already built into the car, which are called on-board chargers, OBCs.

An example of a recharging appliance A of known type is schematically shown in Figure 1.

With reference to this figure, it can be seen that known OBC appliances are provided with an input stage SIN1 comprising one or more input connections Cl, C2, C3 (e.g., three) which can be connected to an external AC power supply line (e.g., of the single-phase, two-phase or three-phase type) and traversable by the incoming AC current.

Then, the input stage SIN1 comprises input filters Fi _n which are connected to each input connection Cl, C2, C3.

It is also known in common OBCs to use two interconnected stages.

The first stage is the Power Factor Correction (PFC), with the aim of drawing from the grid as sinusoidal a current as possible and in phase with the input voltage, so as to absorb the maximum active power without, however, requiring absorption peaks from the grid.

The PFC generally provides a constant or adjustable and stabilized DC voltage at the next stage.

The second stage consists of a DC/DC converter, usually made but not necessarily by means of a circuit LLC, which, by taking the voltage supplied by the PFC, provides a DC voltage at the output, either variable or fixed according to the user’s requirements, while simultaneously achieving the necessary galvanic isolation between the line voltage and the output.

In addition, an output filter Four configured to limit noise generated by the conversion towards the output is arranged downstream of the DC/DC converter. Once flowing through the output filter Four the direct current can, therefore, be sent to the battery EVB.

In addition, in combination with the OBC appliance, which is connectable to an AC power supply line, the use on electric vehicles of a second input stage is known which is connectable to a DC charging station.

In particular, the use of rechargeable batteries at a DC voltage of 800V is becoming increasingly popular for rapid recharging of electric vehicles.

This leads to the increasing spread of charging stations capable of delivering 800V DC.

However, the presence on the national charging networks of numerous charging posts capable of delivering a DC nominal voltage of 400V makes it necessary to deploy additional devices, known as boosters, on electric vehicles capable of enabling charging of the vehicle battery at 800V through 400V charging posts to date already installed in considerable number.

As schematically shown in Figure 1, a second input stage SIN2 comprises two input connections C4 and C5 which can be connected to a DC voltage charging post. The charging post to which the second input stage SIN2 is connectable can be an 800V post or a post capable of delivering 400V.

In addition, the second input stage SIN2 comprises a booster BST configured to trigger when connected to a 400V charging post so as to provide the battery connected downstream with 800V charging voltage.

In order to be able to trip or not to trip the booster BST, the second input stage SIN2 is provided with a bypass circuit connected upstream and downstream of the booster BST and provided with a switch SW which can be controlled in two configurations.

In an initial 800V configuration, the switch SW is closed, resulting in bypassing the booster BST and, therefore, resulting in a direct connection between an 800V charging post and the battery EVB in the vehicle.

In a second 400V configuration, the switch SW is open and the booster BST is then operationally placed between a 400V charging post and the battery EBV of the vehicle. In such a case, the booster BST carries out a conversion of the 400V input voltage into an 800V output voltage towards the battery EVB.

This known solution, however, has some drawbacks.

In particular, in order to enable the electric vehicle to also connect to 400V charging posts, which are still widespread, the use of booster and, therefore, of an additional device on board the vehicle is necessary.

This inevitably entails a higher cost, as well as the need to set up more space on the electric or hybrid vehicle for the recharging appliances.

Description of the Invention

The main aim of the present invention is to devise an appliance for recharging batteries of electric vehicles or the like which allows reducing the overall costs. Another object of the present invention is to devise an appliance for recharging batteries of electric vehicles or the like which allows reducing the space occupied inside the vehicle.

Another object of the present invention is to devise an appliance for recharging batteries of electric vehicles or the like which allows the aforementioned drawbacks of the prior art to be overcome within the framework of a simple, rational, easy and effective to use as well as inexpensive solution.

The aforementioned objects are achieved by the present appliance for recharging batteries of electric vehicles or the like according to the characteristics given in claim 1.

Brief Description of the Drawings

Other characteristics and advantages of the present invention will become more apparent from the description of a preferred, but not exclusive, embodiment of an appliance for recharging batteries of electric vehicles or the like, illustrated by way of an indicative, yet non-limiting example, in the accompanying tables of drawings in which: Figure 1 is a general diagram showing a recharging appliance of known type, where the use of an additional booster device is provided to enable recharging on 400V posts;

Figure 2 is a general diagram showing the recharging appliance according to the invention.

Embodiments of the Invention

With particular reference to Figure 2, reference letter A’ globally denotes an appliance for recharging batteries of electric vehicles or the like.

The appliance A comprises an on-board charging device (OBC’) installed on board of an electric vehicle.

The charging device OBC’ comprises an input stage SIN’ comprising at least one input connection Cl, C2, C3, N connectable to an external AC power supply line (e.g., of the single-phase, two-phase or three-phase type).

Referring to the example in Figure 2, the input stage SIN’ comprises four input connections Cl, C2, C3, N connectable to the three phases and to the neutral of a three-phase AC line, respectively.

The use of such inputs for the connection to single-phase or two-phase lines cannot however be ruled out.

In addition, the charging device OBC’ comprises a power factor correction circuit PFC’ connected to the input stage SIN’.

When the input connections Cl, C2, C3, N are connected to an AC power supply line, the circuit PFC’ is configured to draw from the grid as sinusoidal a current as possible and in phase with the input voltage, so as to absorb the maximum active power without, however, requiring absorption peaks from the grid related to electrolytic capacitance. In this case, then, the circuit PFC provides for a constant or variable DC voltage and stabilized to the next stage.

In addition, the charging device OBC’ comprises a DC/DC converter circuit provided with an input connected to the power factor corrector circuit PFC and with an output connected to the battery EVB of the electric vehicle.

The DC/DC converter circuit is configured to draw the voltage supplied by the circuit PFC and to supply a DC voltage at output, at the same time making the necessary galvanic isolation between line voltage and output.

The DC/DC converter circuit is preferably made by means of a circuit LLC.

In addition, the input stage SIN’ comprises at least one additional input connection C4, C5 connected to the power factor corrector circuit PFC’ and connectable to at least one 400V or 800V DC voltage charging post.

With reference to the preferred embodiment shown in Figure 2, the input stage SIN’ comprises two additional input connections C4, C5 connected to at least one of the phases Cl and to the neutral N respectively, which are used for connection to an AC power supply line.

In addition, the power factor corrector circuit PFC’ is configured to operate in two modes: a first AC operating mode, when the input connections Cl, C2, C3, N of the input stage SIN’ are connected to an external AC power supply line, in which the power factor corrector circuit PFC’ operates as a conventional power factor corrector, thus for the correction of the ratio of the modulus of the active power vector to the modulus of the apparent power vector; a second 400V DC operating mode, when the additional input connections C4, C5 are connected to a 400V DC charging post, in which the power factor corrector circuit PFC’ operates as a booster, thus for the conversion of the 400V input voltage coming from the charging post to an 800V output voltage towards the battery EVB.

Advantageously, the two operating modes can be achieved with the same hardware of the power factor corrector circuit PFC’ .

Specifically, in order to operate in the two separate operating modes, the appliance A comprises at least one connecting circuit SW3, SW4, SW5, SW6 of the power factor corrector circuit PFC’ to the external AC power supply line or to the 400V DC charging post.

Preferably, the connecting circuit SW3, SW4, SW5, SW6 comprises: a plurality of switches SW6 made on the input connections Cl, C2, C3, N respectively for connecting/disconnecting the external AC power supply line to/from the power factor corrector circuit PFC’; a pair of switches SW3, SW4 made on the additional input connections C4, C5 respectively for connecting/disconnecting the 400V DC charging post to/from the input of the power factor corrector circuit PFC’.

Specifically, the connecting circuit SW3, SW4, SW5, SW6 is controllable in two configurations: a first AC configuration wherein the switches SW6 are closed and the switches SW3, SW4 are open and the power factor corrector circuit PFC’ is then connected to the external AC supply line; a second 400V DC voltage configuration wherein the switches SW6 are open and the switches SW3, SW4 are closed and the power factor corrector circuit PFC’ is then connected to the 400V DC voltage charging post.

The appliance A also comprises at least one bypass circuit SW1, SW2 of the DC/DC converter circuit, configured to bypass the DC/DC converter circuit when the power factor corrector circuit PFC’ operates in the second operating mode at 400V direct input voltage.

Thus, in this case, the power factor corrector circuit PFC’ operates as a booster and is directly connected to the 800V battery EVB.

Preferably, the bypass circuit comprises a pair of switches SW1, SW2 connected to the inputs and to the outputs of the DC/DC converter circuit and controllable in two configurations: a first configuration wherein the switches SW1, SW2 are open and the DC/DC converter circuit is then operationally located between the power factor corrector circuit PFC’ and the battery EVB; a second bypass configuration, when the power factor corrector circuit PFC’ operates in the second operating mode at 400V direct input voltage, wherein the switches SW1, SW2 are closed, resulting in bypassing the DC/DC converter circuit and, thus, resulting in direct connection between the power factor corrector circuit PFC’ and the battery EVB of the vehicle.

The appliance A’ is also provided with at least one input voltage sensing device at the input stage SIN’, operationally connected to the power factor corrector circuit PFC’. Therefore, in case the sensing device detects an AC voltage, then the power factor corrector circuit PFC’ is configured to operate in the first AC operating mode.

In case, however, the sensing device detects 400V DC voltage, then the power factor corrector circuit PFC’ is configured to operate in the second operating mode at 400V DC input voltage.

According to a preferred embodiment, the appliance A’ can also be connected to an 800V DC voltage charging post.

In such a case, the appliance A’ can be used for charging through 800V DC voltage charging posts.

According to the possible and preferred embodiment shown in Figure 2, the 800V DC voltage charging post can be connected to the appliance A’ by means of the same additional input connections C4, C5 as the input stage SIN’ .

Specifically, in such a case, the connecting circuit SW3, SW4, SW5, SW6 comprises at least one additional switch SW5 to bypass the power factor corrector circuit PFC’.

Conveniently, according to a preferred embodiment, in addition to the power factor corrector circuit PFC’ the additional switch SW5 is configured to bypass the DC/DC converter circuit as well.

Specifically, the additional switch SW5 is connected between at least one of the additional input connections C4 and the battery EVB, downstream of the DC/DC converter circuit.

Thus, when connected to an 800V charging post, high powers can be delivered directly to the battery EVB, bypassing both the power factor corrector circuit PFC’ and the DC/DC converter circuit.

Specifically, in this case, the connecting circuit SW3, SW4, SW5, SW6 and the bypass circuit SW1, SW2 are controllable in three configurations: a first AC configuration wherein the switches SW6 are closed and the switches SW1, SW2, SW3, SW4, SW5 are open and the power factor corrector circuit PFC’ is then connected to the external AC power supply line, while the DC/DC converter circuit is operationally located between the power factor corrector circuit PFC’ and the battery EVB; a second 400V DC voltage configuration wherein the switches SW5, SW6 are open and the switches SW1, SW2, SW3, SW4 are closed, and the power factor corrector circuit PFC’ is then connected to the 400V DC voltage charging post, while the DC/DC converter circuit is bypassed, resulting in a direct connection between the power factor corrector circuit PFC’ and the vehicle battery EVB; a third 800V DC voltage configuration wherein the switches SW4, SW6 are open and the switches SW3, SW5 are closed and the power factor corrector circuit PFC’ and the DC/DC converter circuit are bypassed, resulting in a direct connection between the 800V charging post and the vehicle battery EVB .

Conveniently, the input stage SIN’ may comprise at least one input filter, not shown in Figure 2, connected to each input connection Cl, C2, C3, N.

In addition, the appliance A’ may comprise at least one output filter FOUT connected downstream of the DC/DC converter circuit and upstream of the battery EVB. The output filter FOUT is configured to limit the noise generated by the conversion towards the battery EVB.

With references to the preferred embodiment shown in Figure 2, the bypass circuit SW1, SW2 is configured to also bypass the output filter FOUT along with the DC/DC converter circuit when the appliance is connected to a 400V or 800V post.

Moreover, in this case, the switches SW3 and SW5 are connected between the additional input connections C4, C5 and the battery EVB, downstream of the output filter FOUT.

Alternative embodiments cannot however be ruled out wherein the filter is not bypassed and is appropriately sized to filter the voltage signal during charging with 400V or 800V posts.

It should also be noted that with reference to 400V or 800V charging posts are meant all those charging posts wherein the nominal reference voltages are 400V and 800V, but wherein the actual output voltages may vary between different voltage values.

It has in practice been ascertained that the described invention achieves the intended objects.

In particular, the fact is emphasized that using the same power factor corrector circuit as a booster reduces the overall cost and dimensions of the appliance.