Pre-charging circuit for electric automobile

Abstract

The utility model discloses an electric vehicle pre-charging circuit, and relates to the technical field of power electronics, the circuit comprises a power battery, a pre-charging resistor R1, a plurality of pre-charging modules and a plurality of electric devices; the pre-charging modules are connected with the electric equipment in a one-to-one correspondence manner; the pre-charging module comprises a main switch, a pre-charging switch and a pre-charging capacitor; wherein the positive electrode output end of the power battery is connected with the first end of the pre-charging switch in each pre-charging module through the pre-charging resistor R1; the positive electrode output end of the power battery is also connected with the first end of the main switch in each pre-charging module; in the pre-charging module, the second end of the pre-charging switch and the second end of the main switch are both connected with the first end of the pre-charging capacitor; the second end of the pre-charging capacitor is connected with the negative electrode output end of the power battery; and the electric equipment is connected in parallel with the two ends of the pre-charging capacitor. According to the technical scheme, the cost is reduced, the integration level is higher, and the occupied volume is greatly reduced.

Description

Technical Field

[0001] The present application relates to the field of power electronics technology, and in particular to a pre-charging circuit for an electric vehicle. Background Art

[0002] With the increasing attention paid to environmental protection and sustainable development around the world, electric vehicles, as a clean energy means of transportation, have received widespread attention and promotion. In electric vehicles, power batteries, as an energy source, can provide direct current for various electrical equipment in electric vehicles, such as motor controllers, DC / AC converters, and electric air conditioners. However, there are only internal resistance and line resistance of the power battery in the high-voltage circuit of the power battery. When the electric vehicle is powered on at high voltage, due to the support capacitor at the back end, the capacitor voltage cannot change suddenly. The support capacitor is equivalent to a short circuit at the moment of power-on, which will generate a surge current of up to several thousand amperes, which will cause damage to these electrical equipment and the melting and adhesion of related contactor contacts. Therefore, in order to protect power battery packs, relays, support capacitors and other equipment from large current shocks when powered on, a high-voltage pre-charging circuit is designed on the electric vehicle. The voltage of the electrical equipment is slowly increased through the pre-charging circuit, which can greatly improve the system safety and ensure the stable operation of the system; and if there is no pre-charging circuit to limit the surge shock current, it will also cause a deep and large current discharge of the power battery at the moment of power-on, which is not good for the life of the power battery itself.

[0003] At present, there are various designs of pre-charging circuits for electric vehicles on the market, but most of them adopt this method: each electrical device is equipped with a corresponding pre-charging circuit, and each pre-charging circuit is independently set and distributed in different positions. When a certain electrical device is powered on, the corresponding pre-charging circuit is controlled to start. However, this method is costly because each pre-charging circuit needs to be equipped with a corresponding pre-charging resistor and anti-reverse diode, and more components will also take up more space, making the circuit larger.

[0004] However, with the continuous development of electric vehicle technology, the market has put forward higher requirements on the cost-effectiveness and volume occupancy of pre-charging circuits. The pre-charging circuits currently on the market can no longer meet the requirements of modern electric vehicles for economy, lightness and small size. Therefore, how to design a pre-charging circuit that reduces both cost and volume has become an urgent problem to be solved in the current field of electric vehicle technology. Utility Model Content

[0005] In order to solve the above-mentioned problem of high cost and large volume of electric vehicle pre-charging circuit, the present application provides an electric vehicle pre-charging circuit.

[0006] In a first aspect, the present application provides a pre-charge circuit for an electric vehicle, adopting the following technical solution: The pre-charge circuit for an electric vehicle includes a power battery, a pre-charge resistor R1, a plurality of pre-charge modules, and a plurality of electrical devices; the pre-charge modules and the electrical devices are connected in one-to-one correspondence;

[0007] The pre-charge module includes a main switch, a pre-charge switch, and a pre-charge capacitor; wherein, the positive output terminal of the power battery is connected to the first end of the pre-charge switch in each pre-charge module through the pre-charge resistor R1; the positive output terminal of the power battery is also connected to the first end of the main switch in each pre-charge module;

[0008] In the pre-charge module, the second end of the pre-charge switch and the second end of the main switch are both connected to the first end of the pre-charge capacitor; the second end of the pre-charge capacitor is connected to the negative output terminal of the power battery; the electrical device is connected in parallel across the two ends of the pre-charge capacitor.

[0009] By adopting the above technical solution, by arranging a plurality of pre-charge modules together, and one end of each pre-charge module is connected to the positive output terminal of the power battery through the pre-charge resistor R1, and the other end is connected to the negative output terminal of the power battery; the pre-charge modules of each electrical device share a pre-charge resistor R1, which not only reduces the cost, but also has a higher integration degree and greatly reduces the occupied volume.

[0010] In a specific feasible implementation, the pre-charge circuit for an electric vehicle further includes an anti-reverse diode D; the anti-reverse diode D is connected between the positive output terminal of the power battery and the pre-charge resistor R1, the positive electrode of the anti-reverse diode D is connected to the positive output terminal of the power battery, and the negative electrode is connected to the pre-charge resistor R1; the positive electrode of the anti-reverse diode D is also connected to the first end of the main switch in each pre-charge module;

[0011] By adopting the above technical solution, by adding the diode D in the circuit, and the diode D is arranged at the input end of each pre-charge module, so that each pre-charge module also shares an anti-reverse diode D, with a lower cost and improved circuit safety.

[0012] In a specific feasible implementation, the pre-charge circuit for an electric vehicle further includes a controller and a multi-channel voltage acquisition module; the voltage acquisition module is connected to the pre-charge module in one-to-one correspondence; the controller is respectively connected to the pre-charge module and the voltage acquisition module;

[0013] The controller is configured to receive the power-on instruction of the electrical device, and control the pre-charge switch in the corresponding pre-charge module to close to charge the corresponding pre-charge capacitor, and is also configured to detect the voltage value of the pre-charge capacitor through the voltage acquisition module. When the voltage value of the pre-charge capacitor reaches a preset value, the pre-charge switch is disconnected, and the corresponding main switch is closed to supply power to the corresponding electrical device by the power battery.

[0014] By adopting the above technical solution, the controller is used to receive instructions and uniformly control and manage the pre-charging modules of each branch, thereby improving the circuit reliability.

[0015] In a specific feasible implementation, the voltage acquisition module includes a plurality of resistors connected in series, and the voltage acquisition module is connected in parallel across the corresponding pre-charging capacitor.

[0016] In a specific feasible implementation, the electric vehicle pre-charging circuit further includes a current acquisition module; the current acquisition module is connected in series in the power battery loop, one end of the current acquisition module is connected to the negative output terminal of the power battery, and the other end is respectively connected to each electrical device and each pre-charging capacitor; the current acquisition module is also connected to the controller, so that the controller can obtain the power battery loop current through the current acquisition module.

[0017] By adopting the above technical solution, a current acquisition module is added to the circuit, and the controller can obtain the current value of the power battery loop in real time, so as to judge whether there is a short circuit situation. When a short circuit occurs, the switch in the corresponding pre-charging module can be controlled to disconnect in time to ensure the safety of the system and avoid damage to multiple electrical devices.

[0018] In a specific feasible implementation, the current acquisition module includes one or more resistors connected in series;

[0019] The controller is connected to both ends of the current acquisition module; the controller obtains the power battery loop current by collecting the voltage value across both ends of the current acquisition module and the resistance value of the current acquisition module.

[0020] In a specific feasible implementation, both the pre-charging switch and the main switch adopt relays.

[0021] In a second aspect, an embodiment of the present application provides an electric vehicle, including the electric vehicle pre-charging circuit described in the first aspect or any feasible implementation of the first aspect.

[0022] One or more technical solutions provided in the embodiments of the present application have at least the following technical effects or advantages:

[0023] 1. By arranging a plurality of pre-charging modules together, and one end of each pre-charging module is connected to the positive output terminal of the power battery through a pre-charging resistor R1, and the other end is connected to the negative output terminal of the power battery; the pre-charging modules of each electrical device share a pre-charging resistor R1, which not only reduces the cost, but also has a higher integration degree and greatly reduces the occupied volume. Description of the Drawings

[0024] Figure 1 It is a schematic diagram of the overall structure of the pre-charging circuit of an electric vehicle in an embodiment of the present application.

[0025] Explanation of the reference numerals in the drawings:

[0026] 1. Pre-charging module; 2. Controller; 3. Voltage acquisition module; 4. Current acquisition module. Specific embodiments

[0027] To make the purpose, technical solutions and advantages of the present application clearer, the following will further describe the embodiments of the present application in detail with reference to the drawings.

[0028] An embodiment of the present application provides a pre-charging circuit for an electric vehicle, as Figure 1 shown, the pre-charging circuit of the electric vehicle includes a power battery, a pre-charging resistor R1, a plurality of pre-charging modules 1 and a plurality of electrical devices; the pre-charging modules 1 and the electrical devices are connected in one-to-one correspondence;

[0029] The pre-charging module 1 includes a main switch, a pre-charging switch and a pre-charging capacitor; wherein, the positive output terminal BAT+ of the power battery is connected to the first end of the pre-charging switch in each of the pre-charging modules 1 through the pre-charging resistor R1; the positive output terminal BAT+ of the power battery is also connected to the first end of the main switch in each of the pre-charging modules 1;

[0030] In the pre-charging module 1, the second end of the pre-charging switch and the second end of the main switch are both connected to the first end of the pre-charging capacitor; the second end of the pre-charging capacitor is connected to the negative output terminal BAT- of the power battery; the electrical device is connected in parallel across the two ends of the pre-charging capacitor.

[0031] According to the technical solution of the present application, by arranging a plurality of pre-charging modules 1 together, and one end of each pre-charging module 1 is connected to the positive output terminal of the power battery through the pre-charging resistor R1, and the other end is connected to the negative output terminal of the power battery; the pre-charging modules 1 of each electrical device share a pre-charging resistor R1, which not only reduces the cost, but also has a higher integration degree and greatly reduces the occupied volume.

[0032] In a possible implementation manner, as Figure 1 shown, the pre-charging circuit of the electric vehicle further includes an anti-reverse diode D; the anti-reverse diode D is connected between the positive output terminal of the power battery and the pre-charging resistor R1, the positive electrode of the anti-reverse diode D is connected to the positive output terminal of the power battery, and the negative electrode is connected to the pre-charging resistor R1; the positive electrode of the anti-reverse diode D is also connected to the first end of the main switch in each of the pre-charging modules 1.

[0033] By adding a diode D to the circuit and setting the diode D at the input end of each pre-charge module 1, each pre-charge module 1 also shares an anti-reverse diode D, which has a lower cost and improves the circuit safety; and through such a setting, a common slow-recovery diode with a small package, low current-carrying capacity, and low cost can be selected for the diode D. Under the same package, the anti-surge current capacity of the slow-recovery diode is generally stronger than that of the fast-recovery diode.

[0034] In a possible implementation manner, as Figure 1 shown, the pre-charge circuit of the electric vehicle further includes a controller 2 and a multi-channel voltage acquisition module 3; the voltage acquisition module 3 is connected to the pre-charge module 1 in one-to-one correspondence; that is, one voltage acquisition module 3 corresponds to one pre-charge module 1; the controller 2 is respectively connected to the pre-charge module 1 and the voltage acquisition module 3;

[0035] The controller 2 is configured to receive a power-on instruction of the electrical device, control the closing of the pre-charge switch in the corresponding pre-charge module 1 to charge the corresponding pre-charge capacitor, and is further configured to detect the voltage value of the pre-charge capacitor through the voltage acquisition module 3. When the voltage value of the pre-charge capacitor reaches a preset value, the pre-charge switch is disconnected, and the corresponding main switch is closed to supply power to the corresponding electrical device by the power battery;

[0036] Specifically, the controller 2 is connected to the main switch and the pre-charge switch in each pre-charge module 1.

[0037] By adopting the controller 2 to receive instructions and uniformly control and manage the pre-charge modules 1 of each branch, the circuit reliability is improved.

[0038] In a possible implementation manner, as Figure 1 shown, the voltage acquisition module 3 includes a plurality of serially connected resistors, and the voltage acquisition module 3 is connected in parallel across the corresponding pre-charge capacitor; since the resistor has a maximum withstand voltage requirement and the voltage in the loop is too large, a plurality of serially connected resistors can be selected for the voltage acquisition module 3, and the specific number can be set by those skilled in the art.

[0039] Specifically, one end of the voltage acquisition module 3 is connected to the first end of the corresponding pre-charge capacitor, and the other end is connected to the negative output terminal BAT- of the power battery; the controller 2 is connected to the middle node between two adjacent resistors in the corresponding voltage acquisition module 3. Using the voltage division principle of the resistor, the controller 2 detects the voltage value of this middle node. When the voltage value reaches the preset value and remains unchanged, it indicates that the pre-charge capacitor is full at this time. The controller 2 can then disconnect the pre-charge switch and close the corresponding main switch to perform the normal charging process.

[0040] In a possible implementation manner, as Figure 1 shown, the pre-charge circuit of the electric vehicle further includes a current acquisition module 4;

[0041] The current acquisition module (4) is connected in series in the power battery circuit. One end of the current acquisition module 4 is connected to the negative output end of the power battery, and the other end is respectively connected to each electrical device and each pre-charge capacitor; the current acquisition module 4 is also connected to the controller 2, so that the controller 2 can obtain the power battery circuit current through the current acquisition module 4.

[0042] By adding the current acquisition module 4 in the circuit and obtaining the current value of the power battery circuit in real time through the controller 2, the circuit condition can be grasped in real time, whether there is a short circuit can be judged, and when a short circuit occurs, the switch in the corresponding pre-charge module 1 can be controlled to disconnect in time to ensure the safety of the system and avoid damage to multiple electrical devices.

[0043] In a possible implementation manner, as Figure 1 shown, the current acquisition module 4 includes one or more resistors connected in series;

[0044] The controller 2 is connected to both ends of the current acquisition module 4; the controller 2 obtains the power battery circuit current by collecting the voltage value at both ends of the current acquisition module 4 and the resistance value of the current acquisition module 4.

[0045] Exemplarily, as Figure 1 shown, the figure shows the case where the current acquisition module 4 only includes one resistor R4. Those skilled in the art can adjust the specific resistance of the current acquisition module 4 according to the actual situation.

[0046] In a possible implementation manner, as Figure 1 shown, both the pre-charge switch and the main switch are relays.

[0047] An embodiment of the present application provides an electric vehicle, including the electric vehicle pre-charge circuit described in the above embodiment or any one of the possible implementation manners.

[0048] The above are all the preferred embodiments of the present application. The protection scope of the present application is not limited hereby. Therefore, all equivalent changes made according to the structure, shape, and principle of the present application should be covered within the protection scope of the present application.

Claims

1. An electric vehicle precharging circuit, characterized in that: It comprises a power battery, a pre-charging resistor R1, a plurality of pre-charging modules (1) and a plurality of electrical appliances; the pre-charging modules (1) and the electrical appliances are connected in a one-to-one correspondence; The pre-charging module (1) comprises a main switch, a pre-charging switch and a pre-charging capacitor; wherein the positive output end of the power battery is connected to the first end of the pre-charging switch in each of the pre-charging modules (1) via the pre-charging resistor R1; the positive output end of the power battery is also connected to the first end of the main switch in each of the pre-charging modules (1); In the pre-charging module (1), the second end of the pre-charging switch and the second end of the main switch are both connected to the first end of the pre-charging capacitor; the second end of the pre-charging capacitor is connected to the negative output end of the power battery; and the electrical equipment is connected in parallel to both ends of the pre-charging capacitor.

2. The electric vehicle precharging circuit according to claim 1, characterized in that: It also includes an anti-reverse diode D; The anti-reverse diode D is connected between the positive output terminal of the power battery and the pre-charging resistor R1, the positive electrode of the anti-reverse diode D is connected to the positive output terminal of the power battery, and the negative electrode is connected to the pre-charging resistor R1; the positive electrode of the anti-reverse diode D is also connected to the first end of the main switch in each pre-charging module (1).

3. The electric vehicle precharging circuit according to claim 1, characterized in that: It also includes a controller (2) and a multi-channel voltage acquisition module (3); the voltage acquisition module (3) is connected to the pre-charging module (1) in a one-to-one correspondence; the controller (2) is connected to the pre-charging module (1) and the voltage acquisition module (3) respectively; The controller (2) is used to receive a power-on instruction of an electrical device and control the pre-charging switch in the corresponding pre-charging module (1) to close so as to charge the corresponding pre-charging capacitor. The controller (2) is also used to detect the voltage value of the pre-charging capacitor through the voltage acquisition module (3). When the voltage value of the pre-charging capacitor reaches a preset value, the pre-charging switch is disconnected and the corresponding main switch is closed so that the power battery can supply power to the corresponding electrical device.

4. The electric vehicle precharging circuit according to claim 3, characterized in that: The voltage acquisition module (3) comprises a plurality of resistors connected in series, and the voltage acquisition module (3) is connected in parallel to both ends of a corresponding pre-charge capacitor.

5. The electric vehicle precharging circuit according to claim 3, characterized in that: It also includes a current acquisition module (4); The current acquisition module (4) is connected in series in the power battery circuit, one end of the current acquisition module (4) is connected to the negative output end of the power battery, and the other end is respectively connected to each electrical device and each pre-charge capacitor; the current acquisition module (4) is also connected to the controller (2) so that the controller (2) obtains the power battery circuit current through the current acquisition module (4).

6. The electric vehicle precharging circuit according to claim 5, characterized in that: The current acquisition module (4) comprises one or more resistors connected in series; The controller (2) is connected to two ends of the current acquisition module (4); the controller (2) obtains the power battery loop current by acquiring voltage values ​​at two ends of the current acquisition module (4) and a resistance value of the current acquisition module (4).

7. The electric vehicle precharging circuit according to claim 1, characterized in that: The pre-charging switch and the main switch both adopt relays.

8. An electric vehicle, characterized in that: The electric vehicle pre-charging circuit comprises the electric vehicle pre-charging circuit according to any one of claims 1 to 7.

Images