Charging and discharging system, vehicle-mounted circuit system and vehicle

Abstract

The utility model discloses a charging and discharging system, a vehicle-mounted circuit system and a vehicle. The charging and discharging system comprises a vehicle-mounted charger circuit and a first DC conversion circuit. The vehicle-mounted charger circuit is used for being connected with an alternating current charging port and a power battery of a vehicle. The first direct-current conversion circuit is used for being connected with a power battery; the vehicle-mounted charger circuit is further used for being connected with a load of a vehicle in an on-off mode. When the vehicle-mounted charger circuit is connected with a load, the vehicle-mounted charger circuit can be configured as follows: the power battery supplies power to the load through the vehicle-mounted charger circuit; the first direct-current conversion circuit is also used for being connected with a load in an on-off manner; and when the first direct current conversion circuit is conducted with the load, the first direct current conversion circuit can be configured as follows: the power battery supplies power to the load through the first direct current conversion circuit. And reliability and stability of power supply of the power battery to the load are improved.

Description

Technical Field

[0001] The present application relates to the field of electricity, and more specifically to a charging and discharging system, a vehicle-mounted circuit system, and a vehicle. Background Art

[0002] When the power battery of an electric vehicle outputs energy, it needs to be stepped down by a DC conversion circuit to supply power to the vehicle's low-voltage load. In the related art, the reliability and stability of the power battery supplying power to the low-voltage load is poor. Utility Model Content

[0003] The utility model is proposed to solve at least one of the above problems. According to the first aspect of the present application, a charging and discharging system is provided, the charging and discharging system comprising: an on-board charger circuit and a first DC conversion circuit; wherein the on-board charger circuit is used to connect to the AC charging port and the power battery of the vehicle; the first DC conversion circuit is used to connect to the power battery; wherein the on-board charger circuit is also used for a disconnectable connection with the load of the vehicle; when the on-board charger circuit is turned on with the load, the on-board charger circuit can be configured as: the power battery supplies power to the load through the on-board charger circuit; the first DC conversion circuit is also used for a disconnectable connection with the load; when the first DC conversion circuit is turned on with the load, the first DC conversion circuit can be configured as: the power battery supplies power to the load through the first DC conversion circuit.

[0004] In one embodiment of the present application, the load includes a battery, and the on-board charger circuit includes an inductor; when the on-board charger circuit is connected to the battery and the first DC conversion circuit is disconnected from the battery, the on-board charger circuit can also be configured to perform alternating charging and discharging between the battery and the inductor to heat the battery.

[0005] In one embodiment of the present application, the on-board charger circuit includes: a power factor correction circuit and a second DC conversion circuit; wherein the power factor correction circuit is used to connect to the AC charging port, and the second DC conversion circuit is used to connect to the power battery.

[0006] In one embodiment of the present application, the load includes a battery; the second DC conversion circuit includes a first bridge circuit and a second bridge circuit, the first bridge circuit is connected to the power factor correction circuit, and the second bridge circuit is connected to the power battery in a switchable manner; when the second bridge circuit is disconnected from the power battery and the on-board charger circuit is connected to the battery, the on-board charger circuit can also be configured as: the battery raises the bus voltage of the second bridge circuit through the on-board charger circuit.

[0007] In one embodiment of the present application, when the on-board charger circuit is disconnected from the load and connected to the AC charging port, the on-board charger circuit is configured as follows: the AC charging device connected to the AC charging port charges the power battery through the on-board charger circuit.

[0008] In one embodiment of the present application, the charging and discharging system further includes: a first switch component, and the power factor correction circuit is connected to the load in an on-off manner through the first switch component.

[0009] In one embodiment of the present application, the power factor correction circuit includes: a positive terminal and a negative terminal, the positive terminal is used to connect to the live terminal of the AC charging port, and the negative terminal is used to connect to the neutral terminal of the AC charging port; the first switch component includes: a first switch and a second switch; the positive terminal is connected to the positive pole of the load through the first switch, and the negative terminal is connected to the negative pole of the load through the second switch; when the first switch and the second switch are both closed, the power factor correction circuit is turned on to the load; when at least one of the first switch and the second switch is turned off, the power factor correction circuit is turned off to the load.

[0010] In one embodiment of the present application, the load includes a battery; the first DC conversion circuit includes a third bridge circuit and a fourth bridge circuit, the third bridge circuit is connected to the battery in an on-off manner, and the fourth bridge circuit is connected to the power battery in an on-off manner; when the fourth bridge circuit is disconnected from the power battery and the third bridge circuit is connected to the battery, the first DC conversion circuit can be configured as follows: the battery raises the bus voltage of the second bridge circuit through the first DC conversion circuit.

[0011] In one embodiment of the present application, the charging and discharging system further includes: a second switch component, and the first DC conversion circuit is connected to the load in an on-off manner through the second switch component.

[0012] In one embodiment of the present application, the first DC conversion circuit includes a third bridge circuit and a fourth bridge circuit, and the fourth bridge circuit is connected to the power battery; the second switch assembly includes: a third switch and a fourth switch; wherein the positive bus of the third bridge circuit is connected to the positive electrode of the load through the third switch, and the negative bus of the third bridge circuit is connected to the negative electrode of the load through the fourth switch; when the third switch and the fourth switch are both closed, the third bridge circuit is conducted with the load; when at least one of the third switch and the fourth switch is opened, the third bridge circuit is disconnected from the load.

[0013] According to the second aspect of the present application, a vehicle-mounted circuit system is also provided, which includes: a power battery, an AC charging port, a load, and any one of the above-mentioned charging and discharging systems; wherein the power battery is connected to the vehicle-mounted charger circuit, and the power battery is also connected to the first DC conversion circuit; the AC charging port is connected to the vehicle-mounted charger circuit; the load is connected to the vehicle-mounted charger circuit in a switchable manner, and the load is also connected to the first DC conversion circuit in a switchable manner.

[0014] According to a third aspect of the present application, a vehicle is also provided, comprising: any one of the above-mentioned on-board circuit systems.

[0015] According to the charging and discharging system, on-board circuit system and vehicle provided in the embodiments of the present application, in addition to being able to supply power to the load through the first DC conversion circuit, the power battery can also supply power to the load through the on-board charger circuit, so that the power battery can supply power to the load through two circuits, thereby improving the reliability and stability of the power battery supplying power to the load. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0017] Figure 1 A schematic diagram of a charging and discharging circuit according to an embodiment of the present utility model;

[0018] Figure 2 This is a schematic diagram of a power battery supplying power to a load according to an embodiment of the utility model;

[0019] Figure 3 This is a schematic diagram of a power factor correction circuit and a battery when they are turned on according to an embodiment of the utility model;

[0020] Figure 4 Based on Figure 3 The schematic diagram of the BUCK circuit configured by the topology diagram;

[0021] Figure 5 This is a schematic diagram of reverse boost pre-charging of a battery according to an embodiment of the present utility model. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solution and advantages of the utility model more obvious, the exemplary embodiments according to the utility model will be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the utility model, rather than all the embodiments of the utility model, and it should be understood that the utility model is not limited to the exemplary embodiments described here. Based on the embodiments of the utility model described in the utility model, all other embodiments obtained by those skilled in the art without creative work should fall within the protection scope of the utility model.

[0023] In the following description, a large number of specific details are given to provide a more thorough understanding of the utility model. However, it is obvious to those skilled in the art that the utility model can be implemented without one or more of these details. In other examples, in order to avoid confusion with the utility model, some technical features known in the art are not described.

[0024] It should be understood that the utility model can be implemented in different forms and should not be interpreted as being limited to the embodiments proposed herein. On the contrary, providing these embodiments will make the disclosure thorough and complete, and will fully convey the scope of the utility model to those skilled in the art.

[0025] In order to thoroughly understand the present invention, a detailed structure will be presented in the following description to illustrate the technical solution proposed by the present invention. The optional embodiments of the present invention are described in detail below, but in addition to these detailed descriptions, the present invention may also have other implementations.

[0026] In conjunction with the accompanying drawings, some embodiments of the present invention are described in detail below. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0027] With the promotion and popularization of new energy vehicles in the market, the number of electric vehicles in the market has increased dramatically. Electric vehicles use high-voltage power batteries as energy output. During the energy output process of power batteries, power conversion circuits are indispensable. As one of the important components of electric vehicles, the stability and safety of on-board charger circuits and DC conversion circuits (DC-DC) are becoming increasingly important. The on-board charger circuit is composed of a power factor correction circuit (PFC circuit), bus capacitors, primary circuits, secondary circuits, transformers, etc., and the DC conversion circuit is composed of a primary high-voltage circuit, a transformer, and a low-voltage primary circuit. The on-board charger circuit and the DC conversion circuit in the related art are two independent products. In the related art, the main function of the on-board charger circuit is to convert AC power into high-voltage DC power for AC charging scenarios of vehicles. The DC conversion circuit is used in all scenarios of vehicles. The DC conversion circuit module in the related art is single, and the DC conversion circuit module is damaged in some extreme environments. If the DC conversion circuit module is damaged, it will affect the operation of the entire vehicle, and in severe cases, it will cause serious safety risks. In the related art, dual DC conversion circuits are usually used, and two sets of completely independent DC conversion circuits are additionally set to ensure stability, but this also brings huge space occupation, cost increase, weight increase and other problems. The above technical problems existing in the related art can be solved by the technical solutions shown in some embodiments of the present application.

[0028] The present application embodiment provides a charging and discharging system, referring to Figure 1 and Figure 2 The charging and discharging system includes: an on-board charger circuit and a first DC conversion circuit; wherein the on-board charger circuit is used to connect to the vehicle's AC charging port and the power battery; the first DC conversion circuit is used to connect to the power battery; wherein the on-board charger circuit is also used for on-off connection with the vehicle's load; when the on-board charger circuit is turned on with the load, the on-board charger circuit can be configured as: the power battery supplies power to the load through the on-board charger circuit; the first DC conversion circuit is also used for on-off connection with the load; when the first DC conversion circuit is turned on with the load, the first DC conversion circuit can be configured as: the power battery supplies power to the load through the first DC conversion circuit.

[0029] In the above scheme, in addition to being able to supply power to the load through the first DC conversion circuit, the power battery can also supply power to the load through the on-board charger circuit, so that the power battery can supply power to the load through two circuits. Compared with the related art, it not only improves the reliability and stability of the power battery supplying power to the low-voltage load, but also reuses the on-board charger circuit to discharge the vehicle load, realizes the reuse of the on-board charger circuit, improves the utilization efficiency and integration of the device, and reduces the cost. The above structures are described in detail below in conjunction with the accompanying drawings.

[0030] When setting up the on-board charger circuit (OBC circuit), the on-board charger circuit is used to connect to the vehicle's AC charging port and the power battery. Specifically, any circuit that can convert the AC power input by the AC charging port into DC power and then charge the power battery can be used as the on-board charger circuit.

[0031] refer to Figure 1 and Figure 2 , the on-board charger circuit may include a power factor correction circuit and a second DC conversion circuit, and the on-board charger circuit is used to charge the vehicle's power battery using an AC charging device. Among them, the power factor correction circuit is used to connect to the vehicle's AC charging port, and the second DC conversion circuit is used to connect to the vehicle's power battery. Exemplarily, the power factor correction circuit is used for a disconnectable connection with the vehicle's AC charging port. Therefore, after the AC charging port is connected to the power battery through the on-board charger circuit, the AC charging device connected to the AC charging port can charge the power battery. During the charging process, the power factor correction circuit is used to rectify AC power into DC power, and the second DC conversion circuit is used to boost the DC power output by the power factor correction circuit and then charge the power battery.

[0032] When setting up a power factor correction circuit, refer to Figure 1 and Figure 2 , the power factor correction circuit may include a bridge circuit and an inductor, and may also include a positive terminal and a negative terminal, the positive terminal is used to connect to the live terminal of the AC charging port, and the negative terminal is used to connect to the neutral terminal of the AC charging port. Exemplarily, the bridge circuit may include three parallel bridge arms, and the number of inductors may be two. One end of each of the two inductors is connected to the positive terminal of the power factor correction circuit, and the positive terminal of the power factor correction circuit is used to connect to the live terminal of the AC charging port. The other ends of the two inductors are respectively connected to a midpoint of a bridge arm. The midpoint of the bridge arm of the bridge arm to which the inductor is not connected in the bridge circuit is directly connected to the negative terminal of the power factor correction circuit, and the negative terminal of the power factor correction circuit is used to connect to the neutral terminal of the AC charging port. Exemplarily, the power factor correction circuit may also include two bus capacitors, one of which is connected between the power factor correction circuit and the AC charging port, and the other is connected between the power factor correction circuit and the second DC conversion circuit. It should be understood that the above are only exemplary embodiments of several configurations of the power factor correction circuit. In addition to the configurations shown above, other configurations may also be used.

[0033] When setting the second DC conversion circuit, various methods can be used. For example, refer to Figure 1 and Figure 2, the second DC conversion circuit may include a first bridge circuit and a second bridge circuit. Among them, the first bridge circuit is connected to the power factor correction circuit. Specifically, the positive busbar of the first bridge circuit is connected to the positive busbar of the power factor correction circuit, and the negative busbar of the first bridge circuit is connected to the negative busbar of the power factor correction circuit. The second bridge circuit is connected to the power battery, and the power battery can be any type of battery pack on the vehicle. Exemplarily, the positive busbar of the second bridge circuit is connected to the positive pole of the power battery, and the negative busbar of the second bridge circuit is connected to the negative pole of the power battery. Exemplarily, the second bridge circuit can be connected to the power battery in a switchable manner, that is, the second bridge circuit can be connected to the power battery in a switchable manner through a switching device such as a contactor or a relay.

[0034] Exemplary, reference Figure 1 and Figure 2 , the second DC conversion circuit may also include a first transformer, the first bridge circuit is connected to the primary side of the first transformer, and the second bridge circuit is connected to the secondary side of the first transformer. Exemplarily, the first bridge circuit includes two bridge arms in parallel, wherein the midpoint of one bridge arm is connected to the positive pole of the primary side of the first transformer, and the midpoint of the other bridge arm is connected to the positive pole of the secondary side of the first transformer. Exemplarily, the second bridge circuit includes two bridge arms in parallel, wherein the midpoint of one bridge arm is connected to the positive pole of the secondary side of the first transformer, and the midpoint of the other bridge arm is connected to the negative pole of the secondary side of the first transformer. It should be understood that the above only exemplarily shows several configurations of the second DC conversion circuit, and other configurations may also be used.

[0035] When setting the first DC conversion circuit, refer to Figure 1 and Figure 2 , the first DC conversion circuit is used to connect to the power battery. That is, the first DC conversion circuit is also connected to the power battery. Exemplarily, the first DC conversion circuit can be connected to the power battery in a switchable manner. When the first DC conversion circuit is specifically set, multiple methods can be used. Exemplarily, the first DC conversion circuit may include a third bridge circuit and a fourth bridge circuit. Among them, the fourth bridge circuit is connected to the power battery, and the power battery can be any type of battery pack on the vehicle. Exemplarily, the positive busbar of the fourth bridge circuit is connected to the positive pole of the power battery, and the negative busbar of the fourth bridge circuit is connected to the negative pole of the power battery. Exemplarily, the fourth bridge circuit can be connected to the power battery in a switchable manner, that is, the fourth bridge circuit can be connected to the power battery in a switchable manner through switching devices such as contactors and relays. It should be understood that the above only exemplarily shows several settings of the first DC conversion circuit. In addition, other settings can also be used.

[0036] refer to Figure 1 and Figure 2, and the on-board charger circuit is also used for on-off connection with the load of the vehicle, and the first DC conversion circuit is also used for on-off connection with the load. That is, in addition to the on-off connection with the AC charging port, the on-board charger circuit is also connected to the load of the vehicle. The first DC conversion circuit is also connected to the load of the vehicle. The load can be any electrical device on the vehicle. Exemplarily, the load can be various types of electrical devices on the vehicle such as but not limited to motor controllers, vehicle controllers, vehicle terminals, motors, compressors, fans, batteries, etc.

[0037] The on-board charger circuit and the first DC conversion circuit can be configured with different functions by utilizing existing control algorithms. Figure 1 and Figure 2 When the on-board charger circuit is connected to the load, the on-board charger can be configured as follows: the power battery supplies power to the load through the on-board charger circuit, that is, the on-board charger circuit is reused as a DC step-down circuit for the power battery to supply power to the load. For example, when the first DC conversion circuit is connected to the load, the first DC conversion circuit can be configured as follows: the power battery supplies power to the load through the first DC conversion circuit, that is, the first DC conversion circuit is reused as a DC step-down circuit for the power battery to supply power to the load.

[0038] For example, when the vehicle is driving, Figure 1 , Figure 2 and Figure 5 , the on-board charger circuit can be turned on with the load (such as Figure 2 and Figure 5 The first DC conversion circuit is connected to the load (such as Figure 2 and Figure 5 Circuit 2 in the figure). At this time, the on-board charger circuit and the first DC conversion circuit perform rectification and voltage reduction synchronously, so that the high-voltage DC power output by the power battery is converted into low-voltage DC power to supply power to the vehicle loads such as but not limited to the battery and the vehicle system. Figure 3 and Figure 4 The on-board charger circuit and the power factor correction circuit and its inductor and capacitor form a BUCK circuit, which reduces the high voltage output of the power battery to a low voltage, and provides a redundant charging circuit for loads on the vehicle such as but not limited to the low-voltage power supply system. During operation, the voltage difference between the two second DC conversion circuits and the first DC conversion circuit can be adjusted so that the second DC conversion circuit and the first DC conversion circuit work periodically and alternately, thereby reducing the heat generated by each DC conversion circuit and reducing losses.

[0039] In the course of work, reference Figure 1 and Figure 2If the on-board charger circuit or the first DC conversion circuit fails, the faulty circuit can be physically disconnected to ensure power supply safety and further reduce the probability of battery power failure. It can be seen that the on-board charger circuit and the first DC conversion circuit are alternately disconnected and connected with the load, so that the DC conversion circuit connection can be confirmed without adding new circuits without affecting the operation of the entire vehicle, thereby ensuring the reliability of the connection.

[0040] Compared with the method of setting up an additional set of redundant DC conversion circuits in the related art, the power battery of the embodiment of the present application can supply power to the load through the on-board charger circuit in addition to the first DC conversion circuit, so that the power battery can supply power to the load through two circuits. Compared with the related art, it not only improves the reliability and stability of the power battery supplying power to the low-voltage load, but also reuses the on-board charger circuit to discharge the vehicle's load, realizes the reuse of the on-board charger circuit, improves the utilization efficiency and integration of the device, and reduces the cost. And there is no need to add a dual DC conversion circuit separately, so that the space and weight occupied by the DC conversion circuit can be reduced.

[0041] When realizing the on-off connection between the power factor correction circuit and the load, various methods can be used. For example, refer to Figure 1 The charging and discharging system may further include: a first switch component, through which the power factor correction circuit is connected to the load in an on-off manner. The first switch component is used to control the on-off between the power factor correction circuit and the load.

[0042] When setting the first switch component, various methods can be used. For example, refer to Figure 1 , the power factor correction circuit may include: a positive terminal and a negative terminal, the positive terminal is used to connect to the live terminal (L terminal) of the AC charging port, and the negative terminal is used to connect to the neutral terminal (N terminal) of the AC charging port. At this time, the first switch component may include: a first switch and a second switch. Figure 1 K1 in represents the first switch, such as Figure 1K2 in represents the second switch. The positive terminal is connected to the positive pole of the load through the first switch, and the negative terminal is connected to the negative pole of the load through the second switch. That is, by connecting the positive terminal of the power factor correction circuit to the positive pole of the load through the first switch, the conduction and disconnection between the positive terminal of the power factor correction circuit and the positive pole of the load can be controlled by the first switch. By connecting the negative terminal of the power factor correction circuit to the negative pole of the load through the second switch, the conduction and disconnection between the negative terminal of the power factor correction circuit and the negative pole of the load can be controlled by the second switch. Specifically, when the first switch and the second switch are both closed, the positive terminal of the power factor correction circuit and the positive pole of the load are turned on, and the negative terminal of the power factor correction circuit and the negative pole of the load are also turned on, then the power factor correction circuit is turned on with the load. When at least one of the first switch and the second switch is turned off, the power factor correction circuit is disconnected from the load. Specifically, when the first switch is opened and the second switch is closed, or when both the first switch and the second switch are opened, or when the second switch is opened and the first switch is closed, the power factor correction circuit is disconnected from the load.

[0043] It should be understood that the above is only an exemplary way of setting the first switch component, and other ways may be used. For example, the first switch component may only include the first switch described above, and the negative terminal of the power factor correction circuit is directly connected to the negative electrode of the load. Alternatively, the first switch component only includes the second switch described above, and the positive terminal of the power factor correction circuit is directly connected to the positive electrode of the load.

[0044] When realizing the on-off connection between the first DC conversion circuit and the load, various methods can be used. Figure 1 The charging and discharging system may further include: a second switch component, through which the first DC conversion circuit is connected to the load in an on-off manner. The on-off between the first DC conversion circuit and the load is controlled by the second switch component.

[0045] When setting the second switch component, various methods can be used. For example, refer to Figure 1 , the first DC conversion circuit includes a third bridge circuit and a fourth bridge circuit, and the fourth bridge circuit is connected to the power battery. In this case, the second switch component may include: a third switch and a fourth switch. Figure 1 K3 in represents the third switch, such as Figure 1K4 in represents the fourth switch. Among them, the positive busbar of the third bridge circuit is connected to the positive pole of the load through the third switch, and the negative busbar of the third bridge circuit is connected to the negative pole of the load through the fourth switch. That is, by connecting the positive busbar of the third bridge circuit to the positive pole of the load through the third switch, the conduction and disconnection between the positive busbar of the third bridge circuit and the positive pole of the load can be controlled by the third switch. By connecting the negative busbar of the third bridge circuit to the negative pole of the load through the fourth switch, the conduction and disconnection between the negative busbar of the third bridge circuit and the negative pole of the load can be controlled by the fourth switch. Specifically, when the third switch and the fourth switch are both closed, the positive busbar of the third bridge circuit and the positive pole of the load are conductive, and the negative busbar of the third bridge circuit and the negative pole of the load are also conductive, then the third bridge circuit is conductive with the load, so that the first DC conversion circuit can be conductive with the load. When the third switch and the fourth switch are both closed, the third bridge circuit is conductive with the load. When at least one of the third switch and the fourth switch is disconnected, the third bridge circuit is disconnected from the load. Specifically, when the third switch is disconnected and the fourth switch is closed, or the third switch and the fourth switch are both disconnected, or the fourth switch is disconnected and the third switch is closed, the third bridge circuit is disconnected from the load, and the first DC conversion circuit is disconnected from the load.

[0046] It should be understood that the above is only an exemplary way of setting the second switch assembly, and other ways may be used. For example, the second switch assembly may only include the third switch mentioned above, and the negative busbar of the third bridge circuit is directly connected to the negative electrode of the load. Alternatively, the second switch assembly only includes the fourth switch mentioned above, and the positive busbar of the third bridge circuit is directly connected to the positive electrode of the load.

[0047] In addition, the above-mentioned on-board charger circuit and the first DC conversion circuit can also be configured with other functions by utilizing existing control algorithms.

[0048] Exemplary, reference Figure 1 , Figure 2 , Figure 3 and Figure 4, the load may include a battery, and the on-board charger circuit may include an inductor. At this time, when the on-board charger circuit is turned on with the battery, and the first DC conversion circuit is disconnected from the battery, the on-board charger circuit can also be configured as follows: the battery and the inductor are alternately charged and discharged to heat the battery. When used, the battery has poor charging and discharging characteristics at low temperatures, and its filtering and surge absorption capabilities are greatly reduced. Its short-term large current discharge capability is poor, and it cannot meet the requirements under some extremely low temperature conditions. Even in extreme cases, the fuse cannot be blown in time after a short circuit occurs. In this embodiment, in a low temperature environment, the first DC conversion circuit can be disconnected from the battery, and the power battery can normally step down and supply power to the loads other than the battery on the vehicle through the first DC conversion circuit. The on-board charger circuit is turned on with the battery, and the on-board charger circuit is configured as follows: the battery and the inductor are alternately charged and discharged to heat the battery.

[0049] Exemplarily, when the load may include a battery, the on-board charger circuit may include a power factor correction circuit, and the power factor correction circuit may include an inductor. At this time, when the on-board charger circuit is turned on with the battery, and the first DC conversion circuit is disconnected from the battery, the power factor correction circuit can also be configured as: alternating charging and discharging between the battery and the inductor to heat the battery. When used, the battery has poor charging and discharging characteristics at low temperatures, greatly reduces the filtering and surge absorption capabilities, and has poor short-term large current discharge capabilities, which cannot meet the requirements of some extreme low temperature conditions. Even in extreme cases, the fuse cannot be blown in time after a short circuit occurs. In this embodiment, in a low temperature environment, the first DC conversion circuit can be disconnected from the battery, and the power battery can provide normal voltage reduction and power supply to the loads other than the battery on the vehicle through the first DC conversion circuit. The on-board charger circuit is turned on with the battery, and the on-board charger circuit is configured as: alternating charging and discharging between the battery and the inductor to heat the battery. Specifically, the inductor and the bridge circuit in the power factor correction circuit can be alternately configured as a boost circuit and a buck circuit, forming an alternating pulse oscillating current in the loop between the power factor correction circuit and the battery, performing pulse charge and discharge on the battery, and utilizing the internal resistance of the battery to generate heat to heat the battery to a normal operating temperature. Figure 3 and Figure 4 The above-mentioned boost circuit can be a BUCK circuit, and the above-mentioned buck circuit can be a BOOST circuit. The power factor correction circuit is alternately configured as a BUCK circuit and a BOOST circuit, and an alternating pulse oscillating current is formed in the loop between the power factor correction circuit and the battery to perform pulse charging and discharging on the battery.

[0050] Exemplary, reference Figure 1 and Figure 5, the load may include a battery. The second DC conversion circuit may include a first bridge circuit and a second bridge circuit, the first bridge circuit is connected to the power factor correction circuit, and the second bridge circuit is connected to the power battery in an on-off manner. When the second bridge circuit is disconnected from the power battery and the on-board charger circuit is connected to the battery, the on-board charger circuit can also be configured as follows: the battery raises the bus voltage of the second bridge circuit through the on-board charger circuit. During application, the second bridge circuit and the power battery may be connected by a connection that can be on and off, such as but not limited to a contactor or a relay. When the second bridge circuit is disconnected from the power battery, if it is necessary to close the second bridge circuit and the power battery. However, when the power battery has been discharging normally at high voltage, the on-board charger circuit can be connected to the battery, and the on-board charger circuit can be configured as follows: the battery raises the bus voltage of the second bridge circuit through the on-board charger circuit, so that the bus voltage of the second bridge circuit is as close to or equal to the voltage output by the power battery as possible, and the bus of the second bridge circuit is boosted and pre-charged, and then the switch between the bus of the second bridge circuit and the power battery is closed, so as to ensure that the pressure difference between the two ends of the switch such as but not limited to the contactor is small enough at the moment of closure, thereby completing the vehicle pre-charging process.

[0051] Exemplarily, when the on-board charger circuit is disconnected from the load and the on-board charger circuit is connected to the AC charging port, the on-board charger circuit can also be configured as follows: the AC charging device connected to the AC charging port charges the power battery through the on-board charger circuit. That is, when the power battery needs to be charged through the AC charging port, the on-board charger circuit can be disconnected from the load and the on-board charger circuit can be connected to the AC charging port. After the AC charging port is connected to the AC charging device, the AC charging device connected to the AC charging port charges the power battery through the on-board charger circuit to complete the charging process of the power battery.

[0052] Exemplary, reference Figure 1 and Figure 5, the load may also include a battery. The first DC conversion circuit may also include a third bridge circuit and a fourth bridge circuit, the third bridge circuit is connected to the battery in an on-off manner, and the fourth bridge circuit is connected to the power battery in an on-off manner. When the fourth bridge circuit is disconnected from the power battery and the third bridge circuit is connected to the battery, the first DC conversion circuit can be configured as follows: the battery raises the bus voltage of the second bridge circuit through the first DC conversion circuit. During application, the fourth bridge circuit and the power battery may be connected by a connection that can be on and off, such as but not limited to a contactor or a relay. When the fourth bridge circuit is disconnected from the power battery, if it is necessary to close the fourth bridge circuit and the power battery. However, when the power battery has been normally discharging high voltage to the outside, the third bridge circuit can be connected to the battery, so that the first DC conversion circuit can be connected to the battery, and the first DC conversion circuit can be configured as follows: the battery raises the bus voltage of the fourth bridge circuit through the first DC conversion circuit, so that the bus voltage of the fourth bridge circuit is as close to or equal to the voltage output by the power battery to the outside as possible, and the bus of the fourth bridge circuit is boosted and pre-charged, and then the switch between the bus of the fourth bridge circuit and the power battery is closed, so as to ensure that the pressure difference between the two ends of the switch such as but not limited to the contactor is small enough at the moment of closure, thereby completing the vehicle pre-charging process.

[0053] The above-mentioned devices have different working modes in different application scenarios. Figure 1 to Figure 5 , taking Table 1 as an example, the specific situations in various working modes are explained.

[0054] In the working mode, the first switch K1, the second switch K2, the third switch K3, and the fourth switch K4 are all closed, and the on-board charger circuit and the first DC conversion circuit are used to step down the high-voltage DC power output by the power battery and then supply power to the load.

[0055] In working mode 2, the first switch K1 and the second switch K2 are disconnected, the third switch K3 and the fourth switch K4 are closed, and the first DC conversion circuit is used to step down the high-voltage DC power output by the power battery and then supply power to the load. The on-board charger circuit is connected to the AC charging port, and the on-board charger circuit is used to convert the AC power input from the AC charging port into DC power and step up the voltage to charge the power battery.

[0056] In working mode three, the first switch K1 and the second switch K2 are disconnected, and the third switch K3 and the fourth switch K4 are closed. At this time, the on-board charger circuit may fail or may be suspended, and the first DC conversion circuit is used to step down the high-voltage DC power output by the power battery and then supply power to the load.

[0057] In working mode four, the first switch K1 and the second switch K2 are closed, and the third switch K3 and the fourth switch K4 are opened. At this time, the first DC conversion circuit may fail or may be suspended, and the on-board charger circuit is used to step down the high-voltage DC power output by the power battery and then supply power to the load.

[0058] In working mode five, the first switch K1 and the second switch K2 are closed, and the third switch K3 and the fourth switch K4 are opened. At this time, the first DC conversion circuit is disconnected from the battery, and the power battery can step down the voltage to supply power to other loads through the first DC conversion circuit. The on-board charger circuit is connected to the battery, and the on-board charger circuit can be alternately configured as a boost circuit and a buck circuit, so that the battery is alternately charged and discharged, which is used to heat the battery.

[0059] In working mode six, the first switch K1 and the second switch K2 are closed, and the third switch K3 and the fourth switch K4 are disconnected. When the second bridge circuit is disconnected from the power battery, if it is necessary to close the second bridge circuit and the power battery. However, when the power battery has been normally discharging high voltage to the outside, the on-board charger circuit can be connected to the battery, and the on-board charger circuit can be configured as follows: the battery raises the bus voltage of the second bridge circuit through the on-board charger circuit, so that the bus voltage of the second bridge circuit is as close to or equal to the voltage output by the power battery as possible, and the bus of the second bridge circuit is boosted and pre-charged, and then the switch between the bus of the second bridge circuit and the power battery is closed, so as to ensure that the voltage difference between the two ends of the switch such as but not limited to the contactor is small enough at the moment of closure, thereby completing the vehicle pre-charging process.

[0060] In working mode seven, the first switch K1 and the second switch K2 are disconnected, and the third switch K3 and the fourth switch K4 are closed. When the fourth bridge circuit is disconnected from the power battery, if it is necessary to close the fourth bridge circuit and the power battery. However, when the power battery has been normally discharging high voltage to the outside, the third bridge circuit can be connected to the battery to connect the first DC conversion circuit to the battery, and the first DC conversion circuit is configured as follows: the battery raises the bus voltage of the fourth bridge circuit through the first DC conversion circuit, so that the bus voltage of the fourth bridge circuit is as close to or equal to the voltage output by the power battery as possible, and the bus of the fourth bridge circuit is boosted and pre-charged, and then the switch between the bus of the fourth bridge circuit and the power battery is closed, so as to ensure that the pressure difference between the two ends of the switch such as but not limited to the contactor is small enough at the moment of closure, thereby completing the vehicle pre-charging process.

[0061] Table 1 - Working status of each device in different working modes

[0062]

[0063] In the various embodiments shown above, in addition to being able to supply power to the load through the first DC conversion circuit, the power battery can also supply power to the load through the on-board charger circuit, so that the power battery can supply power to the load through two circuits. Compared with the related art, the existing functional topology is used to realize the operation of the dual DC conversion circuit, which greatly reduces the situation where the vehicle is broken down due to the failure of the DC conversion circuit, improves the availability of the vehicle, and improves the reliability and stability of the power battery supplying power to the low-voltage load. At the same time, the switching of the working mode of the dual DC conversion circuit can also be used to reduce the impact caused by the long-term operation of each DC conversion circuit device and extend the service life of the DC conversion circuit module. In addition, the on-board charger circuit is reused to discharge the load of the vehicle, so as to realize the reuse of the on-board charger circuit, improve the utilization efficiency and integration of the device, and reduce the cost. There is no need to separately add a dual DC conversion circuit, so that the space occupation and weight occupation of the DC conversion circuit can be reduced.

[0064] In some of the above embodiments, by utilizing different existing control algorithms and a bidirectional on-board charger circuit, BUCK step-down rectification is achieved, and the DCDC step-down function is realized. Together with the original first DC conversion circuit, a dual DCDC application in some scenarios is formed, thereby achieving the requirements for low-voltage power supply safety in some scenarios.

[0065] In some of the above embodiments, on the basis of existing hardware, a switch component is added to disconnect the battery and the first DC conversion circuit at low temperatures, so that the power battery directly supplies the entire vehicle through the first DC conversion circuit. The battery uses the on-board charger circuit to achieve pulse heating charging, thereby ensuring the performance of the battery in some scenarios. It can also achieve safety isolation in the event of a fault, further ensuring the safety of vehicle use.

[0066] The present invention realizes the function of the dual DC conversion circuit in some safety scenarios by adding a switch component, using the existing control method, and switching the working mode in different scenarios, ensuring the safety and stability of the low-voltage power supply of the vehicle. The existing circuit can also be used to achieve battery heating, ensuring that the battery can work normally in a low-temperature environment and ensuring basic performance.

[0067] In addition, the embodiment of the present application also provides a vehicle-mounted circuit system, referring to Figure 1 to Figure 5, the vehicle circuit system includes: a power battery, an AC charging port, a load, and any one of the above-mentioned charging and discharging systems. Among them, the power battery is connected to the vehicle charger circuit. For example, the power battery is connected to the second DC conversion circuit in the vehicle charger circuit, and the power battery is also connected to the first DC conversion circuit; the AC charging port is connected to the vehicle charger circuit. For example, the AC charging port is connected to the power factor correction circuit in the vehicle charger circuit; the load is connected to the vehicle charger circuit in a switchable manner, and the load is also connected to the first DC conversion circuit in a switchable manner. The above-mentioned power battery can be any type of battery pack. The above-mentioned AC charging port can be any interface that can be electrically connected to an external charging gun. The above-mentioned load can be any power-consuming load on the vehicle. For example, the load can be various types of electrical devices on the vehicle such as but not limited to motor controllers, vehicle controllers, vehicle terminals, motors, compressors, fans, batteries, etc.

[0068] Furthermore, the present application embodiment also provides a vehicle, referring to Figure 1 to Figure 5 The vehicle includes: any one of the above-mentioned vehicle-mounted circuit systems. The vehicle may be, for example but not limited to, an electric vehicle, a hybrid vehicle, etc.

[0069] The utility model has been described through the above embodiments, but it should be understood that the above embodiments are only for the purpose of example and description, and are not intended to limit the utility model to the scope of the described embodiments. In addition, it can be understood by those skilled in the art that the utility model is not limited to the above embodiments, and more variations and modifications can be made according to the teachings of the utility model, and these variations and modifications all fall within the scope of protection claimed by the utility model. The protection scope of the utility model is defined by the attached claims and their equivalents.

Claims

1. A charging and discharging system, It is characterized in that include: On-board charger circuit, used to connect to the vehicle's AC charging port and power battery; A first DC conversion circuit, used to be connected to the power battery; The on-board charger circuit is also used for on-off connection with the load of the vehicle; when the on-board charger circuit is connected to the load, the on-board charger circuit can be configured as follows: the power battery supplies power to the load through the on-board charger circuit; The first DC conversion circuit is also used for an on-off connection with the load; when the first DC conversion circuit is connected to the load, the first DC conversion circuit can be configured as follows: the power battery supplies power to the load through the first DC conversion circuit.

2. The charging and discharging system according to claim 1, It is characterized in that The load includes a battery, and the on-board charger circuit includes an inductor; When the on-board charger circuit is connected to the battery and the first DC conversion circuit is disconnected from the battery, the on-board charger circuit can also be configured to alternately charge and discharge the battery and the inductor to heat the battery.

3. The charging and discharging system according to claim 1, It is characterized in that The on-board charger circuit comprises: a power factor correction circuit and a second DC conversion circuit; Wherein, the power factor correction circuit is used to connect to the AC charging port, and the second DC conversion circuit is used to connect to the power battery.

4. The charging and discharging system according to claim 3, It is characterized in that The load includes a storage battery; the second DC conversion circuit includes a first bridge circuit and a second bridge circuit, the first bridge circuit is connected to the power factor correction circuit, and the second bridge circuit is connected to the power battery in an on-off manner; When the second bridge circuit is disconnected from the power battery and the on-board charger circuit is connected to the storage battery, the on-board charger circuit can also be configured as follows: the storage battery raises the bus voltage of the second bridge circuit through the on-board charger circuit.

5. The charging and discharging system according to claim 3, It is characterized in that The power factor correction circuit is used for connecting to the AC charging port in an on-off manner; When the on-board charger circuit is disconnected from the load and connected to the AC charging port, the on-board charger circuit is configured such that the AC charging device connected to the AC charging port charges the power battery through the on-board charger circuit.

6. The charging and discharging system according to claim 3, It is characterized in that Also includes: A first switch component, the power factor correction circuit is connected to the load in an on-off manner through the first switch component.

7. The charging and discharging system according to claim 6, It is characterized in that The power factor correction circuit includes: a positive terminal and a negative terminal, the positive terminal is used to connect to the live terminal of the AC charging port, and the negative terminal is used to connect to the neutral terminal of the AC charging port; The first switch assembly includes: a first switch and a second switch; the positive terminal is connected to the positive electrode of the load through the first switch, and the negative terminal is connected to the negative electrode of the load through the second switch; When both the first switch and the second switch are closed, the power factor correction circuit is connected to the load; when at least one of the first switch and the second switch is opened, the power factor correction circuit is disconnected from the load.

8. The charging and discharging system according to claim 4, It is characterized in that The load includes a storage battery; the first DC conversion circuit includes a third bridge circuit and a fourth bridge circuit, the third bridge circuit is connected to the storage battery in an on-off manner, and the fourth bridge circuit is connected to the power battery in an on-off manner; When the fourth bridge circuit is disconnected from the power battery and the third bridge circuit is connected to the storage battery, the first DC conversion circuit can be configured as follows: the storage battery raises the bus voltage of the second bridge circuit through the first DC conversion circuit.

9. The charging and discharging system according to claim 1, It is characterized in that Also includes: A second switch component, the first DC conversion circuit is connected to the load in an on-off manner through the second switch component.

10. The charging and discharging system according to claim 9, It is characterized in that The first DC conversion circuit includes a third bridge circuit and a fourth bridge circuit, and the fourth bridge circuit is connected to the power battery; The second switch assembly includes: a third switch and a fourth switch; wherein the positive busbar of the third bridge circuit is connected to the positive electrode of the load through the third switch, and the negative busbar of the third bridge circuit is connected to the negative electrode of the load through the fourth switch; When the third switch and the fourth switch are both closed, the third bridge circuit is connected to the load; when at least one of the third switch and the fourth switch is opened, the third bridge circuit is disconnected from the load.

11. A vehicle circuit system, It is characterized in that include: The charging and discharging system according to any one of claims 1 to 10; A power battery connected to the on-board charger circuit and also connected to the first DC conversion circuit; An AC charging port connected to the on-board charger circuit; The load is connected to the on-board charger circuit in an on-off manner and is also connected to the first DC conversion circuit in an on-off manner.

12. A vehicle, It is characterized in that include: The vehicle-mounted circuit system as claimed in claim 11.

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