Battery charging device for electric vehicle or similar vehicle

Abstract

Device (1) for charging a battery of an electric vehicle or the like, comprising: an input stage (S IN) comprising at least one input circuit (C1, C2, C3) and at least one switch (SW1, SW2, SW3) that can be closed / opened; a power unit (POW); comprising at least one measuring device (PR); an interface unit (SYS) operably connected to the switches (SW1, SW2, SW3) and configured to send at least one closing / opening signal to the switches (SW1, SW2, SW3); wherein the interface unit (SYS) comprises a detection device (PC) operatively connected upstream of said switches (SW1, SW2, SW3) and configured to detect the presence of said voltage and to generate at least one presence / absence signal, the interface unit (SYS) being configured to convert the presence / absence signal into a closing / opening signal; a measuring device (PR) is connected downstream of the input circuits (C1, C2, C3).

Description

Technical Field

[0001] The invention relates to a device for charging a battery of an electric vehicle or the like. Background Art

[0002] As is known, electric vehicles utilize part of the chemical energy stored in one or more batteries (so-called "electric vehicle batteries", EVB) to convert into electrical energy and subsequently transfer the electrical energy to a motor unit for ground propulsion of the electric vehicle.

[0003] In order to be able to charge the battery regularly, electric vehicles are equipped with special devices already built into the vehicle, these special devices are called on-board chargers OBC.

[0004] Figure 1 An example of such a known arrangement is schematically shown.

[0005] refer to Figure 1 It can be seen that the known device is provided with an input stage S IN, which includes one or more input circuits C1, C2, C3 (for example, three input circuits), which can be connected to an external AC power supply line (for example, single-phase, two-phase or three-phase type) and passed through by the input alternating current.

[0006] In more detail, closable / openable switches SW1, SW2, SW3 (eg, relay type) are arranged on the input circuits C1, C2, C3, respectively, to connect or disconnect the input circuits themselves to the power line.

[0007] In addition, one of the input circuits C1 includes one or more auxiliary switches SW4, SW5 (for example, in the case where there are three input circuits C1, C2, C3, there are two auxiliary switches), which connect it to the other input circuits C2, C3 and are responsible for switching from a three-phase configuration to a single-phase configuration, or from a single-phase configuration to a three-phase configuration.

[0008] Next, the input stage S IN includes an input filter F IN1 、F IN2 、F IN3 , the input filter F IN1 、F IN2 、F IN3 They are arranged in the input circuits C1, C2, C3 respectively, downstream of the switches SW1, SW2, SW3 and the auxiliary switches SW4, SW5, and are responsible for filtering interference from the downstream to prevent the interference from reaching the power line.

[0009] In fact, once the switches SW1, SW2, SW3 and / or the auxiliary switches SW4, SW5 are crossed, the AC current enters the input filter F IN1 、F IN2 、F IN3 , then from the input filter F IN1 、F IN2 、F IN3 The output end is transported to the next component of the device.

[0010] In this respect, the device of known type is also equipped with a power unit POW operating at high voltage, which is arranged downstream of the input stage S IN and is configured to receive an alternating current from the input stage S IN at an input and to deliver a predefined direct current to the battery EVB at an output.

[0011] To achieve this purpose, a special power circuit is provided in the power unit POW, which includes, among other components, a power factor correction PFC device for correcting the current input waveform and a DC / DC converter device.

[0012] In addition, an output filter F is arranged downstream of the power unit POW. OUT , the output filter F OUT is configured to limit the effect of disturbances generated by the transitions on the output.

[0013] Therefore, once the output filter F OUT After being passed through, DC power can be delivered to the battery EVB.

[0014] It should be noted that, in order to fully exert its function, the power factor correction PFC device must be properly adjusted according to the instantaneous value and phase of the voltage at the input end of the power unit POW.

[0015] In fact, this allows a power factor correction PFC device to be advantageously used to correct the phase shift and the shape of the current with respect to the relevant voltage, thereby complying with international regulations.

[0016] In this sense, the known device comprises a command unit COM operatively situated between the input stage S IN and the power unit POW.

[0017] In this case, the command unit COM is provided with a resistor divider PR configured to measure the input voltage and its zero crossing points; thus, once these measurements have been made, the command unit COM can adjust the power factor correction PFC device accordingly.

[0018] Finally, the known device comprises an interface unit SYS connected to a control unit CNT of the electric vehicle and configured to send information to the control unit CNT regarding, for example, the values ​​of input voltage and current, electrical conversion efficiency, etc.

[0019] Unlike the power unit POW, the interface unit SYS operates at low voltage and is usually shielded; this prevents any electromagnetic interference generated by the high-voltage switches present in the power unit POW, propagating first to the command unit COM and then to the interface unit SYS, from being transmitted to the control unit CNT.

[0020] In addition, the interface unit SYS is connected to the switches SW1 , SW2 , SW3 , and is configured to control the opening and closing of the switches SW1 , SW2 , SW3 according to whether there is a voltage at the input terminal.

[0021] Furthermore, the interface unit SYS is also connected to the auxiliary switches SW4, SW5, and is configured to control the opening and closing of the auxiliary switches SW4, SW5 to switch from the three-phase configuration to the single-phase configuration, and vice versa.

[0022] In order to enable the interface unit SYS to do this, in a known arrangement a resistor divider PR is connected to the input circuit C1 , C2 , C3 upstream of each of the switches SW1 , SW2 , SW3 and the auxiliary switches SW4 , SW5 .

[0023] In fact, the above connection mode allows the resistor divider PR to be used not only for making the above measurements but also for regulating the closing / opening of the switches SW1 , SW2 , SW3 and the auxiliary switches SW4 , SW5 of the interface unit SYS.

[0024] Therefore, in the known arrangement, the resistor divider PR is configured to detect the presence of a voltage at the input terminal and, after detection, to generate a presence / absence signal which is sent to the interface unit SYS.

[0025] The interface unit SYS then switches this presence / absence signal into a closed / open signal, which is used to command or not command one or more of the switches SW1, SW2, SW3 and / or the auxiliary switches SW4, SW5 to close, and in doing so, allows AC current to flow to the power unit POW to be converted into DC power and thus delivered to the battery EVB.

[0026] However, this technological solution is not without problems.

[0027] In this regard, it must first be stated that the command unit COM must be placed close to the power unit POW in order to adjust the power factor correction PFC device.

[0028] However, switching at the high voltage present in the power unit POW may generate electromagnetic interference in the command unit COM, which propagates through the connections from the resistor divider PR to the upstream inputs of the switches SW1, SW2, SW3 and the auxiliary switches SW4, SW5, possibly causing severe disturbances to the input AC power.

[0029] Furthermore, it must be taken into account that the resistor divider PR is by definition a dissipative component and that, therefore, if current flows through it when it is not necessary, this results in considerable energy waste.

[0030] Taking this fact into account, it is of course easy to understand that connecting a resistor divider PR upstream of the switches SW1 , SW2 , SW3 and the auxiliary switches SW4 , SW5 is a rather inconvenient technical solution.

[0031] In fact, in this case, once the input stage S IN is connected to the supply line, the resistor divider PR is crossed by the alternating current, whether the switches SW1 , SW2 , SW3 and the auxiliary switches SW4 , SW5 are open or closed.

[0032] Obviously, this fact leads to unnecessary wastage of energy within the device and, as a direct consequence, to a reduction in the overall efficiency of the device.

[0033] Finally, it is also worth mentioning that the instantaneous voltage measured by the resistor divider PR upstream of the switches SW1 , SW2 , SW3 and the auxiliary switches SW4 , SW5 differs, in some cases significantly, from the voltage actually present at the input of the command unit COM.

[0034] This fact is mainly due to the input filter F IN1 、F IN2 、F IN3 The presence of and the resulting phase correction.

[0035] This difference therefore means that the value measured by the resistor divider PR must be appropriately corrected; this is usually done by programming the command unit COM so that the measured value matches the value actually present at the input of the command unit itself.

[0036] However, it is obvious that this is unlikely to return accurate results, especially if the voltage waveform is distorted. Summary of the invention

[0037] The main purpose of the present invention is to devise a device for charging the batteries of electric vehicles or similar vehicles which has an efficient, precise and accurate operation, capable of reducing energy dissipation and electromagnetic interference compared to the aforementioned prior art.

[0038] Another object of the present invention is to devise a device for charging the batteries of electric vehicles or similar vehicles that can overcome the above-mentioned drawbacks of the prior art within the framework of a simple, rational, easy and effective use and affordable solution.

[0039] The above-mentioned objects are achieved by such a device for charging a battery of an electric vehicle or the like. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Other features and advantages of the invention will become more apparent from the description of a preferred but not exclusive embodiment of a device for charging the battery of an electric vehicle or similar vehicle, which is illustrated by way of schematic but not limiting example in the accompanying drawings, in which:

[0041] Figure 1 A device of known type is schematically shown;

[0042] Figure 2 A device according to the invention is shown schematically. DETAILED DESCRIPTION

[0043] Specific reference Figure 2 , reference numeral 1 globally indicates a device for charging a battery of an electric vehicle or the like.

[0044] The device 1 for charging the battery of an electric vehicle or the like comprises at least one input stage S IN, which comprises at least one input circuit C1, C2, C3 connectable to at least one AC power line, and at least one switch SW1, SW2, SW3 positioned along the input circuit C1, C2, C3, which at least one switch SW1, SW2, SW3 is closable / openable to connect at least one input circuit C1, C2, C3 to the power line or to disconnect at least one input circuit C1, C2, C3 from the power line.

[0045] Preferably, the switches SW1 , SW2 , SW3 are bidirectional relay type switches.

[0046] Advantageously, the input stage S IN comprises at least one input filter F IN1 、F IN2 、F IN3 , the at least one input filter F IN1 、F IN2 、F IN3 Arranged downstream of the switches SW1 , SW2 , SW3 along the input circuit C1 , C2 , C3 .

[0047] As will become clearer in the remainder of this disclosure, the input filter F IN1 、F IN2 、FIN3 Suitable for filtering interference coming downstream of the input filter itself.

[0048] The device 1 then comprises at least one power unit POW arranged downstream of the input stage S IN and provided with an output connectable to at least one battery EVB of at least one electric vehicle.

[0049] Specifically, the power unit POW is adapted to receive alternating current at an input terminal and to transmit a predefined direct current at an output terminal to be sent to the battery EVB.

[0050] To this end, the power unit POW comprises at least one power factor correction PFC device.

[0051] Furthermore, the power unit POW may further include other components, such as at least one DC / DC converter (schematically shown in the figure) and / or one or more rectifiers (not shown in the figure).

[0052] In this regard it should be pointed out that the high voltage conversion taking place within the power unit POW may generate electromagnetic interference which may propagate upstream.

[0053] It is in this respect that, as expected, the input filter F IN1 、F IN2 、F IN3 The presence of can filter the interference from the power unit POW, ensuring that these interferences are eliminated before reaching the power line.

[0054] The arrangement then comprises at least one command unit COM operatively situated between the input stage SIN and the power unit POW and comprising at least one measuring device PR connected to the input circuit C1 , C2 , C3 .

[0055] In the present case, the measuring device PR is adapted to acquire at least one characteristic parameter of the voltage, the command unit COM being configured to adjust the power factor correction PFC device as a function of the acquired characteristic parameter.

[0056] In this case, the characteristic parameters correspond to the voltage value and its waveform.

[0057] In particular, the measuring device PR comprises at least one resistive voltage divider.

[0058] Specifically, the measuring device PR consists of a resistor divider.

[0059] According to the invention, a measuring device PR is connected downstream of the input circuit C1 , C2 , C3 .

[0060] To be precise, Figure 2As shown, the measuring device PR is connected to the input circuit C1, C2, C3, located at the input filter F IN1 、F IN2 、F IN3 downstream.

[0061] In this respect, it is important to point out that the above-described connection between the measuring device PR and the input circuits C1 , C2 , C3 allows a double benefit to be achieved.

[0062] Firstly, it ensures that any electromagnetic interference present in the command unit COM does not propagate upstream of the switches SW1 , SW2 , SW3 due to the proximity between the command unit COM and the power unit POW, thus avoiding the injection of interference into the network in compliance with electromagnetic compatibility regulations.

[0063] Secondly, the above connection also makes it possible to measure the voltage value actually corresponding to the input terminal of the power unit POW.

[0064] This means that, in this case, no correction of the measured values ​​is necessary.

[0065] Furthermore, this fact greatly simplifies the control of the power factor correction PFC device, making its correction more precise.

[0066] Conveniently, the device comprises at least one output filter F OUT , which is arranged downstream of the power unit POW.

[0067] Furthermore, the arrangement comprises at least one interface unit SYS, which is connected to at least one control unit CNT of the electric vehicle.

[0068] In this regard, the interface unit SYS is also connected to the command unit COM and is configured to send signals from the command unit COM to the control unit CNT, which signals contain information about, for example, electrical conversion parameters, such as input and output current, operating temperature, electrical conversion efficiency, etc.

[0069] Furthermore, the interface unit SYS is connected to the switches SW1 , SW2 , SW3 and is configured to send at least one closing / opening signal to the switches SW1 , SW2 , SW3 .

[0070] According to the present invention, the interface unit SYS includes at least one detection device PC, which is operably connected to the input circuits C1, C2, C3 and is located upstream of the switches SW1, SW2, SW3, and the detection device PC is configured to detect the presence of voltage and generate at least one presence / absence signal after detection, and the interface unit SYS is configured to convert the presence / absence signal into a closed / open signal.

[0071] This means, in practice, that the interface unit SYS closes / keeps closed the switches SW1 , SW2 , SW3 if the detection device PC detects the presence of a voltage upstream of the switches SW1 , SW2 , SW3 .

[0072] Otherwise, that is to say if the detection device PC detects the absence of voltage upstream of the switches SW1 , SW2 , SW3 , the interface unit SYS opens / keeps the switches itself open.

[0073] At this point it may be convenient to explain that Figure 2 In the preferred embodiment of the device 1 shown, the input stage S IN comprises:

[0074] At least a first input circuit C1 , at least a second input circuit C2 and at least a third input circuit C3 connected in parallel to the detection device PC; and

[0075] at least a first switch SW1 arranged along the first input circuit C1, at least a second switch SW2 arranged along the second input circuit C2, and at least a third switch SW3 arranged along the third input circuit C3, respectively; and

[0076] At least a first input filter F is arranged along the first input circuit C1 (located downstream of the first switch SW1) IN1 , at least a second input filter F arranged along the second input circuit C2 (located downstream of the second switch SW2) IN2 and at least a third input filter F arranged along the third input circuit C3 (located downstream of the third switch SW3) IN3 .

[0077] According to a preferred embodiment, the input stage S IN basically comprises three input circuits C1, C2, C3, three switches SW1, SW2, SW3 and three input filters F IN1 、F IN2 、F IN3 .

[0078] However, it cannot be excluded that the input stage S IN may include a different number of input circuits C1 , C2 , C3 , the input filter F IN1 、F IN2 、F IN3 And switches SW1, SW2, SW3.

[0079] For example, solutions may be envisaged in which the input stage S IN is provided with two input circuits, each provided with a switch and an input filter, or other solutions known to those skilled in the art.

[0080] However, it should be understood that what is described in the remainder of the present disclosure with respect to only one of the input circuits C1 , C2 , C3 (eg referring to the latter in the singular) is considered to be equally valid for any other input circuit C1 , C2 , C3 .

[0081] Similar considerations apply to switches SW1, SW2, SW3 and input filter F IN1 、F IN2 、F IN3 .

[0082] As an example and with reference to the preferred embodiment, if the detection device PC detects the presence of a voltage upstream of two of the three switches SW1 , SW2 , SW3 , the detection device PC will generate two presence signals and one absence signal, respectively.

[0083] The interface unit SYS converts the two presence signals into two closing signals to be sent to the above two switches SW1, SW2, and converts the absence signal into an opening signal to be sent to the remaining switch SW3.

[0084] This means that, normally, the interface unit SYS closes / keeps the switches SW1 , SW2 , SW3 closed, the detection device PC detects the presence of a voltage upstream of the switches SW1 , SW2 , SW3 and opens / keeps the other switches open.

[0085] Continue description Figure 2 In the preferred embodiment shown, it is convenient that the first input circuit C1 includes at least a first auxiliary switch SW4, which is connected upstream of the input end of the first switch SW1 and downstream of the output end of the second switch SW2, and is closable / openable to connect the first input circuit C1 to the second input circuit C2 or disconnect the first input circuit C1 from the second input circuit C2.

[0086] In addition, the first input circuit C1 also includes at least a second auxiliary switch SW5, which is connected upstream of the input end of the first switch SW1 and downstream of the output end of the third switch SW3, and is closable / openable to connect the first input circuit C1 to the third input circuit C3 or disconnect the first input circuit C1 from the third input circuit C3.

[0087] In this regard, the interface unit SYS is configured to send at least one closing / opening signal to the first and second auxiliary switches SW4 and SW5 to enable the first input circuit C1 to be connected / disconnected with the second input circuit C2 and with the third input circuit C3 .

[0088] In particular, if the detection device PC detects the presence of a voltage only upstream of the first input circuit C1 , the detection device PC generates a single presence signal which is automatically converted by the interface unit SYS into a closing signal for the first and second auxiliary switches SW4 , SW5 .

[0089] This means, in fact, that if the detection device PC detects the presence of a voltage only upstream of the first input circuit C1 , the interface unit SYS closes / keeps closed the first auxiliary switch SW4 and the second auxiliary switch SW5 .

[0090] Therefore, in this particular case, the interface unit SYS closes / keeps closed the first switch SW1 , the first auxiliary switch SW4 , and the second auxiliary switch SW5 .

[0091] For ease of explanation, this technical means allows single-phase power to be supplied to the device 1 in the absence of voltage on the second input circuit C2 and the third input circuit C3, thereby obtaining an output power greater than that obtained using only the first input circuit C1.

[0092] Preferably, the first auxiliary switch SW4 and the second auxiliary switch SW5 are bidirectional relay type switches.

[0093] In other words, the first auxiliary switch SW4 and the second auxiliary switch SW5 are very similar in function to the first switch SW1 , the second switch SW2 , and the third switch SW3 .

[0094] Usefully, the detection device PC comprises at least one capacitive spacer.

[0095] Specifically, the detection device PC consists of a capacitive voltage divider.

[0096] In this regard, it is important to point out that providing a capacitive voltage divider type detection device PC upstream of the switches SW1, SW2, SW3 for detecting the input voltage makes it possible to control the opening and closing of the switches SW1, SW2, SW3 in an absolutely advantageous manner while avoiding unnecessary energy consumption.

[0097] In fact, unlike resistor dividers, capacitor dividers are ideal non-dissipative components; therefore, capacitor dividers can be used for voltage sensing upstream of switches SW1, SW2, SW3 without incurring expensive energy waste.

[0098] In other words, the energy dissipated by using a capacitive voltage divider for voltage sensing is completely negligible compared to the energy dissipated by using a resistive voltage divider for this purpose.

[0099] It is therefore easy to understand that the fact that a capacitive voltage divider is provided enables the power consumption required for detecting the presence / absence of a voltage to be almost completely reduced.

[0100] It has been established in practice that the described invention achieves the intended objects.

[0101] In particular, it is emphasized that the special means of connecting a capacitive voltage divider upstream of the switch for detecting the input voltage makes it possible to control the opening and closing of the switch in a decidedly advantageous manner and at the same time reduce the energy consumption compared to the above-mentioned prior art.

[0102] Furthermore, it is emphasized that the special means of connecting the resistive divider downstream of the input filter ensures that any electromagnetic interference in the command unit cannot propagate upstream of the switch and, therefore, the alternating current at the input is not disturbed.

[0103] Furthermore, it is important to point out that the same method can also be used to measure the voltage value that actually corresponds to the input terminal of the command unit.

[0104] In this way, correction of these values ​​by special programming of the command unit is completely unnecessary and the adjustment of the power factor correction device proves to be simplified to a certain extent.

Claims

1. A device (1) for charging a battery of an electric vehicle or similar vehicle, comprising: at least one input stage (S IN), the at least one input stage (S IN) comprising at least one input circuit (C1, C2, C3) connectable to at least one AC power line and at least one switch (SW1, SW2, SW3) located along the input circuit (C1, C2, C3), the at least one switch (SW1, SW2, SW3) being closable / openable to connect / disconnect the at least one input circuit (C1, C2, C3) to / from the power line; at least one power unit (POW), arranged downstream of the input stage (S IN), the at least one power unit (POW) having an output terminal connectable to at least one battery (EVB) of at least one electric vehicle and comprising at least one power factor correction (PFC) device, the power unit (POW) being adapted to receive an alternating current at an input terminal and to output a predefined direct current at an output terminal, the direct current being delivered to the battery (EVB); at least one command unit (COM), the at least one command unit (COM) being operatively located between the input stage (SIN) and the power unit (POW), and the at least one command unit (COM) comprising at least one measuring device (PR), the at least one measuring device (PR) being connected to the input circuit (C1, C2, C3) and being suitable for acquiring at least one characteristic parameter of the voltage, the command unit (COM) being configured to adjust the power factor correction (PFC) device according to the acquired characteristic parameter; at least one interface unit (SYS), the at least one interface unit (SYS) being connected to at least one control unit (CNT) of the electric vehicle, the interface unit (SYS) being operatively connected to the switches (SW1, SW2, SW3) and being configured to send at least one closing / opening signal to the switches (SW1, SW2, SW3); It is characterized in that The interface unit (SYS) comprises at least one detection device (PC), the at least one detection device (PC) being operatively connected to the input circuit (C1, C2, C3), being located upstream of the switches (SW1, SW2, SW3), and the at least one detection device (PC) being configured to detect the presence of the voltage and, depending on the result of the detection, to generate at least one presence / absence signal, the interface unit (SYS) being configured to convert the presence / absence signal into the closing / opening signal; The measuring device (PR) is connected downstream of the input circuit (C1, C2, C3).

2. The device (1) according to claim 1, characterized in that The detection device (PC) comprises at least one capacitive voltage divider.

3. Device (1) according to one or more of the preceding claims, characterized in that The input stage (SIN) comprises at least one input filter (F IN1 、F IN2 、F IN3 ), the at least one input filter (F IN1 、F IN2 、F IN3 ) is arranged along the input circuit (C1, C2, C3) and is located downstream of the switch (SW1, SW2, SW3).

4. Device (1) according to one or more of the preceding claims, characterized in that The input stage (SIN) comprises: at least a first input circuit (C1), at least a second input circuit (C2) and at least a third input circuit (C3) connected in parallel to the detection device (PC); and at least a first switch (SW1) arranged along the first input circuit (C1), at least a second switch (SW2) arranged along the second input circuit (C2), and at least a third switch (SW3) arranged along the third input circuit (C3); At least a first input filter (F) arranged downstream of the first switch (SW1) along the first input circuit (C1) IN1 ), at least a second input filter (F) arranged downstream of the second switch (SW2) along the second input circuit (C2); IN2 ) and at least a third input filter (F) arranged downstream of the third switch (SW3) along the third input circuit (C3) IN3 ).

5. The device (1) according to claim 4, characterized in that The first input circuit (C1) comprises: at least a first auxiliary switch (SW4), the first auxiliary switch (SW4) being connected upstream of an input end of the first switch (SW1) and downstream of an output end of the second switch (SW2), and the first auxiliary switch (SW4) being closable / openable to connect / disconnect the first input circuit (C1) with the second input circuit (C2); and At least a second auxiliary switch (SW5), the second auxiliary switch (SW5) is connected upstream of the input end of the first switch (SW1) and downstream of the output end of the third switch (SW3), and the second auxiliary switch (SW5) is closable / disconnectable to connect / disconnect the first input circuit (C1) with the third input circuit (C3).

6. Device (1) according to one or more of the preceding claims, characterized in that The device (1) comprises at least one output filter (F OUT ), the output filter (F OUT ) is arranged downstream of the power unit (POW).

7. Device (1) according to one or more of the preceding claims, characterized in that The measuring device (PR) comprises at least one resistive voltage divider.

8. Device (1) according to one or more of the preceding claims, characterized in that At least one of the switches (SW1, SW2, SW3), the first auxiliary switch (SW4) and the second auxiliary switch (SW5) is of a bidirectional relay type.

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