A pre-charging system, method and module

Abstract

The present invention relates to the field of charging, and specifically discloses a pre-charging system, which includes a vehicle end and a main relay, wherein the vehicle end is connected to the output end of the main relay, and the pre-charging system also includes a control unit and a pre-charging switching unit, wherein the control unit controls the operation of the main relay and the pre-charging switching unit, the output end of the pre-charging switching unit is connected to the vehicle end, and before closing the main relay, the pre-charging switching unit pre-charges the vehicle end in advance, and when the voltage value of the vehicle end capacitor reaches a constant value, the pre-charging switching unit stops working. In this embodiment, the vehicle end capacitor is pre-charged by the pre-charging switching unit, and when the voltage value of the vehicle end capacitor reaches a constant value, the pre-charging switching unit stops working, the main relay is closed, and the electric vehicle is charged. At this time, the vehicle end capacitor will not generate a large impact current, and will not cause the relay to stick, thereby extending the service life of the relay.

Description

Technical Field

[0001] The present invention relates to the field of electric vehicle charging, and in particular to a pre-charging system, method and module. Background Art

[0002] With the continuous development of new energy industry, the construction progress of charging piles has accelerated, and the market share of AC charging piles has become higher and higher. At the same time, there are more and more problems, one of which is the problem of relay adhesion. When the AC charging pile is charging, it directly closes the main relay. Due to the capacitance at the vehicle end, there is a large impact current at the moment of closing, which accelerates the carbonization of the relay contacts, causing the relay to stick, greatly shortening the service life of the relay. Summary of the invention

[0003] The present invention provides a pre-charging system to solve the problem in the prior art that directly closing the main relay during charging of an AC charging pile may cause the relay to stick, greatly shortening the service life of the relay.

[0004] The technical solution adopted by the present invention is:

[0005] A pre-charging system comprises a vehicle end and a main relay, wherein the vehicle end is connected to an output end of the main relay, and further comprises:

[0006] A control unit, wherein the control unit controls the operation of the main relay and the pre-charging switching unit;

[0007] A pre-charging switching unit, wherein the output end of the pre-charging switching unit is connected to the vehicle end. Before closing the main relay, the pre-charging switching unit pre-charges the vehicle end. When the voltage value of the vehicle end capacitor reaches a constant value, the pre-charging switching unit stops working.

[0008] Furthermore, the pre-charging system includes an AC voltage sampling unit, and the AC voltage sampling unit is respectively connected to the pre-charging switching unit and the power supply end.

[0009] Further, the pre-charging switching unit includes a single-pole double-position relay K1, a double-pole single-position relay K2 and a single-pole single-position relay K3, the third end of the single-pole double-position relay K1 is connected to the power supply end, the fourth end of the single-pole double-position relay K1 is connected to the fifth end of the double-pole single-position relay K2, the sixth end of the double-pole single-position relay K2 and the fourth end of the double-pole single-position relay K2 are connected to the vehicle end, the third end of the double-pole single-position relay K2 is connected to the fourth end of the single-pole single-position relay K3, and the third end of the single-pole single-position relay K3 is connected to the fifth end of the single-pole double-position relay K1.

[0010] Furthermore, the pre-charging switching unit also includes a rectifier bridge, the fourth end of the single-pole double-position relay K1 is connected to the fifth end of the double-pole single-position relay K2 via a diode D1 in the rectifier bridge, and the third end of the double-pole single-position relay K2 is connected to the fourth end of the single-pole single-position relay K3 via a diode D3 in the rectifier bridge.

[0011] Furthermore, the pre-charging system also includes a voltage transformer, and the third end of the single-pole double-position relay K1 is connected to the power supply end via the voltage sensor.

[0012] Further, when the pre-charging switching unit is not working, the third end of the single-pole double-position relay K1 is connected to the fifth end of the single-pole double-position relay K1, and the double-pole single-position relay K2 and the single-pole single-position relay K3 are disconnected; when the pre-charging switching unit is working, the third end of the single-pole double-position relay K1 is connected to the fourth end of the single-pole double-position relay K1, and the double-pole single-position relay K2 and the single-pole single-position relay K3 are closed.

[0013] The present invention provides a pre-charging method to solve the problem in the prior art that directly closing a main relay during charging of an AC charging pile may cause relay adhesion, greatly shortening the service life of the relay.

[0014] A pre-charging method, comprising:

[0015] When a charging signal is obtained, the third terminal of the single-pole double-position relay K1 is controlled to be connected to the fifth terminal of the single-pole double-position relay K1, and the double-pole single-position relay K2 and the single-pole single-position relay K3 are closed;

[0016] Get the AC voltage sampling value;

[0017] When the voltage value across the sampling resistor R1 is a constant value within the set range, it is determined whether the voltage value across the sampling resistor R1 is within the set range;

[0018] Get the AC voltage value of the main circuit;

[0019] Determine whether the direction of the main circuit AC voltage is consistent with the direction of the vehicle-end capacitor voltage;

[0020] If the voltage value across the sampling resistor R1 is within the set range and the direction of the main circuit AC voltage is consistent with the direction of the vehicle-end capacitor voltage, the third end of the single-pole double-position relay K1 is controlled to disconnect the fifth end of the single-pole double-position relay K1, the double-pole single-position relay K2 and the single-pole single-position relay K3 are disconnected and the main relay is allowed to close.

[0021] Furthermore, the voltage setting range calculation formula of the sampling resistor R1 is:

[0022] Ub=(Ua*R1) / (R1+Rx),

[0023] Among them, Ub is the calculated voltage value across the sampling resistor R1, Ua is the voltage value at the power supply end, R1 is the sampling resistor, Rx is the discharge resistor at the vehicle end, and the value range of Rx is 51KΩ~2MΩ.

[0024] Furthermore, if the voltage value across the sampling resistor R1 is within the set range and the direction of the main circuit AC voltage is inconsistent with the direction of the vehicle-end capacitor voltage, the main relay is closed when the direction of the main circuit AC voltage is consistent with the direction of the vehicle-end capacitor voltage.

[0025] In order to solve the problem in the prior art that directly closing the main relay during charging of an AC charging pile may cause the relay to stick, greatly shortening the service life of the relay, the present invention provides a pre-charging module.

[0026] A pre-charging module, comprising:

[0027] An acquisition unit, the acquisition unit is used to acquire a charging signal and an AC voltage sampling value;

[0028] The judging unit judges whether the voltage value at both ends of the sampling resistor R1 is within the set range when the voltage value at both ends of the sampling resistor R1 is a constant value within the set range, and judges whether the direction of the main circuit AC voltage is consistent with the direction of the vehicle-end capacitor voltage;

[0029] The control unit, when obtaining the charging signal, controls the third end of the single-pole double-position relay K1 to connect to the fifth end of the single-pole double-position relay K1, and the double-pole single-position relay K2 and the single-pole single-position relay K3 are closed; when the voltage value at both ends of the sampling resistor R1 is within the set range and the direction of the main circuit AC voltage is consistent with the direction of the vehicle-end capacitor voltage, the third end of the single-pole double-position relay K1 is controlled to disconnect the fifth end of the single-pole double-position relay K1, the double-pole single-position relay K2 and the single-pole single-position relay K3 are disconnected and the main relay is allowed to close.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] The pre-charging system provided by the present invention includes a control unit and a pre-charging switching unit. The control unit controls the operation of a main relay and the pre-charging switching unit. The vehicle-end capacitor is pre-charged through the pre-charging switching unit before closing the main relay. When the voltage value of the vehicle-end capacitor reaches a constant value, the pre-charging switching unit stops working, and then the main relay is closed to charge the vehicle end. The present invention solves the problem that when the main relay is directly closed, the instantaneous impact current at the time of closing will accelerate the carbonization of the relay contacts and cause the relay to stick due to the presence of capacitors at the vehicle end. The present invention can extend the service life of the main relay. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0033] Figure 1 A functional block diagram of a pre-charging system provided by an embodiment of the present invention;

[0034] Figure 2 A circuit diagram of a pre-charge switching unit provided in an embodiment of the present invention;

[0035] Figure 3 A flowchart of a pre-charging method provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0036] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0037] Figure 1 A principle block diagram of a pre-charging system provided by an embodiment of the present invention is shown, the pre-charging system includes a vehicle end and a main relay, the vehicle end is connected to the output end of the main relay, the pre-charging system also includes a control unit and a pre-charging switching unit, wherein the control unit controls the operation of the main relay and the pre-charging switching unit, the output end of the pre-charging switching unit is connected to the vehicle end, before closing the main relay, the pre-charging switching unit pre-charges the vehicle end, when the voltage value of the vehicle end capacitor reaches a constant value, the pre-charging switching unit stops working, the present embodiment pre-charges the vehicle end capacitor through the pre-charging switching unit, when the voltage value of the vehicle end capacitor reaches a constant value, the pre-charging switching unit stops working, the main relay is closed, and the electric vehicle is charged, at this time, the vehicle end capacitor will not generate a large impact current, will not cause the relay to stick, thereby extending the service life of the relay.

[0038] It should be noted that the constant value in this embodiment is not a fixed value. For different types of electric vehicles, the vehicle-end capacitor voltage value is different. The above-mentioned vehicle-end capacitor voltage value reaches a constant value refers to the voltage value at both ends of a certain model of capacitor after charging is completed.

[0039] Furthermore, the pre-charging system includes an AC voltage sampling unit, which is respectively connected to the pre-charging switching unit and the power supply end. In this embodiment, the vehicle-end capacitor voltage value and the power supply end voltage value are collected by the AC voltage collection unit, and the collected voltage value is transmitted to the control unit.

[0040] Furthermore, if Figure 2 As shown, the pre-charging switching unit includes a single-pole double-position relay K1, a rectifier bridge, a double-pole single-position relay K2 and a single-pole single-position relay K3, the third end of the single-pole double-position relay K1 is connected to the power supply end, the fourth end of the single-pole double-position relay K1 is connected to the anode of the diode D1 in the rectifier bridge, the fifth end of the single-pole double-position relay K1 is connected to the third end of the single-pole single-position relay K3, the fourth end of the single-pole single-position relay K3 is connected to the cathode of the diode D3 in the rectifier bridge, the cathode of the diode D1 in the rectifier bridge is connected to the fifth end of the double-pole single-position relay K2, the sixth end of the double-pole single-position relay K2 and the fourth end of the double-pole single-position relay K2 are connected to the vehicle end, and the anode of the diode D3 in the rectifier bridge is connected to the third end of the double-pole single-position relay K2.

[0041] Specifically, Figure 2 As shown, when charging is required, the control unit drives the third end of the single-pole double-position relay K1 to connect to the fourth end, and the double-pole single-position relay K2 and the single-pole single-position relay K3 are closed. At this time, the AC power is output to the vehicle end through the voltage sensor and the rectifier bridge to pre-charge the vehicle end capacitor;

[0042] When the pre-charging is finished, the control unit drives the third end of the single-pole double-position relay K1 to connect to the fifth end, the double-pole single-position relay K2 and the single-pole single-position relay K3 are disconnected, and the power supply end no longer pre-charges the vehicle end.

[0043] Furthermore, the pre-charging system also includes a voltage transformer. The third end of the single-pole double-position relay K1 is connected to the power supply end via the voltage sensor. In this embodiment, the AC voltage is converted into a low voltage through the voltage transformer, so that the vehicle-end capacitor can be charged conveniently.

[0044] This embodiment also provides a pre-charging method, using the above-mentioned pre-charging system, specifically, the pre-charging method includes:

[0045] When a charging signal is obtained, the third terminal of the single-pole double-position relay K1 is controlled to be connected to the fifth terminal of the single-pole double-position relay K1, and the double-pole single-position relay K2 and the single-pole single-position relay K3 are closed;

[0046] Get the voltage value across the sampling resistor R1;

[0047] When the voltage value across the sampling resistor R1 is a constant value within the set range, it is determined whether the voltage value across the sampling resistor R1 is within the set range;

[0048] Get the AC voltage value of the main circuit;

[0049] Determine whether the direction of the main circuit AC voltage is consistent with the direction of the vehicle-end capacitor voltage;

[0050] If the voltage value across the sampling resistor R1 is within the set range and the direction of the main circuit AC voltage is consistent with the direction of the vehicle-end capacitor voltage, the third end of the single-pole double-position relay K1 is controlled to disconnect the fifth end of the single-pole double-position relay K1, the double-pole single-position relay K2 and the single-pole single-position relay K3 are disconnected and the main relay is allowed to close.

[0051] Furthermore, the voltage setting range calculation formula of the sampling resistor R1 is:

[0052] Ub=(Ua*R1) / (R1+Rx),

[0053] Among them, Ub is the calculated voltage value across the sampling resistor R1, Ua is the voltage value at the power supply end, R1 is the sampling resistor, Rx is the discharge resistor at the vehicle end, and the value range of Rx is 51KΩ~2MΩ.

[0054] It should be noted that different types of vehicles have different resistance values ​​of the discharge resistor Rx at the vehicle end. Therefore, after collecting the vehicle-end discharge resistors of many electric vehicles on the market, this embodiment obtains that the value range of Rx is 51KΩ~2MΩ. Therefore, by substituting the value range of the vehicle-end discharge resistor Rx into the above calculation formula, a reasonable range of the voltage value across the sampling resistor R1 can be obtained.

[0055] Furthermore, if the voltage value across the sampling resistor R1 is within the set range and the direction of the main circuit AC voltage is inconsistent with the direction of the vehicle-end capacitor voltage, the main relay is closed when the direction of the main circuit AC voltage is consistent with the direction of the vehicle-end capacitor voltage.

[0056] This embodiment further provides a pre-charging module, which applies the above-mentioned pre-charging system. Specifically, the pre-charging module includes:

[0057] An acquisition unit, the acquisition unit is used to acquire a charging signal and an AC voltage sampling value;

[0058] A judgment unit, when the voltage value across the sampling resistor R1 is a constant value within a set range, judges whether the voltage value across the sampling resistor R1 is within the set range, and judges whether the direction of the main circuit AC voltage is consistent with the direction of the vehicle-end capacitor voltage;

[0059] The control unit, when obtaining the charging signal, controls the third end of the single-pole double-position relay K1 to connect to the fifth end of the single-pole double-position relay K1, and the double-pole single-position relay K2 and the single-pole single-position relay K3 are closed; when the voltage value at both ends of the sampling resistor R1 is within the set range and the direction of the main circuit AC voltage is consistent with the direction of the vehicle-end capacitor voltage, the third end of the single-pole double-position relay K1 is controlled to disconnect the fifth end of the single-pole double-position relay K1, the double-pole single-position relay K2 and the single-pole single-position relay K3 are disconnected and the main relay is allowed to close.

[0060] To sum up, the pre-charging system provided in this embodiment pre-charges the vehicle-end capacitor through the pre-charging switching unit before closing the main relay. When the voltage value of the vehicle-end capacitor reaches a constant value, the pre-charging switching unit stops working, and then the main relay is closed to charge the vehicle end. The present invention solves the problem of directly closing the main relay. Due to the presence of capacitors at the vehicle end, the instantaneous impact current of closing will accelerate the carbonization of the relay contacts and cause the relay to stick. The present invention can extend the service life of the main relay. In addition, the present invention requires small space and low cost. It only needs to add 3 small relays and a rectifier bridge, which can all be welded on the circuit board, greatly saving the space of the charging pile.

[0061] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, segment or portion of code that includes one or more executable instructions for implementing the steps of a specific logical function or process, and the scope of the preferred embodiments of the present invention includes alternative implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in the reverse order depending on the functions involved, which should be understood by those skilled in the art to which the embodiments of the present invention belong.

[0062] A person skilled in the art may understand that all or part of the steps in the above-mentioned embodiment method may be completed by instructing related hardware through a program, and the program may be stored in a computer-readable storage medium, which, when executed, includes one or a combination of the steps of the method embodiment.

[0063] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0064] The above embodiments are only descriptions of the preferred implementation modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary engineering and technical personnel in the field should fall within the protection scope determined by the claims of the present invention.

Claims

1. A pre-charging method, characterized in that: A pre-charging system is applied, the pre-charging system includes a pre-charging switching unit, the pre-charging switching unit includes a single-pole double-throw relay K1, a rectifier bridge, a double-pole single-throw relay K2 and a single-pole single-throw relay K3, the third end of the single-pole double-throw relay K1 is connected to the power supply end, the fourth end of the single-pole double-throw relay K1 is connected to the anode of the diode D1 in the rectifier bridge, the fifth end of the single-pole double-throw relay K1 is connected to the third end of the single-pole single-throw relay K3, the fourth end of the single-pole single-throw relay K3 is connected to the cathode of the diode D3 in the rectifier bridge, the cathode of the diode D1 in the rectifier bridge is connected to the fifth end of the double-pole single-throw relay K2, the sixth end of the double-pole single-throw relay K2 and the fourth end of the double-pole single-throw relay K2 are connected to the vehicle end, the anode of the diode D3 in the rectifier bridge is connected to the third end of the double-pole single-throw relay K2, and the pre-charging method includes: When a charging signal is obtained, the third terminal of the single-pole double-throw relay K1 is controlled to be connected to the fifth terminal of the single-pole double-throw relay K1, and the double-pole single-throw relay K2 and the single-pole single-throw relay K3 are closed; Get the voltage value across the sampling resistor R1; When the voltage value across the sampling resistor R1 is a constant value, it is determined whether the voltage value across the sampling resistor R1 is within a set range; Get the AC voltage value of the main circuit; Determine whether the direction of the main circuit AC voltage is consistent with the direction of the vehicle-end capacitor voltage; If the voltage value across the sampling resistor R1 is within the set range and the direction of the main circuit AC voltage is consistent with the direction of the vehicle-end capacitor voltage, the third terminal of the single-pole double-throw relay K1 is controlled to disconnect the fifth terminal of the single-pole double-throw relay K1, the double-pole single-throw relay K2 and the single-pole single-throw relay K3 are disconnected and the main relay is allowed to close.

2. A pre-charging method according to claim 1, characterized in that, The pre-charging system includes a vehicle end and a main relay, wherein the vehicle end is connected to an output end of the main relay, and further includes: A control unit, wherein the control unit controls the operation of the main relay and the pre-charging switching unit; A pre-charging switching unit, wherein the output end of the pre-charging switching unit is connected to the vehicle end. Before closing the main relay, the pre-charging switching unit pre-charges the vehicle end. When the voltage value of the vehicle end capacitor reaches a constant value, the pre-charging switching unit stops working.

3. A pre-charging method according to claim 1, characterized in that, The pre-charging system comprises an AC voltage sampling unit, and the AC voltage sampling unit is respectively connected to the pre-charging switching unit and the power supply end.

4. A pre-charging method according to claim 1, characterized in that: The third end of the single-pole double-throw relay K1 is connected to the power supply end, the fourth end of the single-pole double-throw relay K1 is connected to the fifth end of the double-pole single-throw relay K2, the sixth end of the double-pole single-throw relay K2 and the fourth end of the double-pole single-throw relay K2 are connected to the vehicle end, the third end of the double-pole single-throw relay K2 is connected to the fourth end of the single-pole single-throw relay K3, and the third end of the single-pole single-throw relay K3 is connected to the fifth end of the single-pole double-throw relay K1.

5. A pre-charging method according to claim 1, characterized in that: The pre-charging switching unit also includes a rectifier bridge, the fourth end of the single-pole double-throw relay K1 is connected to the fifth end of the double-pole single-throw relay K2 via a diode D1 in the rectifier bridge, and the third end of the double-pole single-throw relay K2 is connected to the fourth end of the single-pole single-throw relay K3 via a diode D3 in the rectifier bridge.

6. A pre-charging method according to claim 1, characterized in that: The pre-charging system further includes a voltage transformer, and the third end of the single-pole double-throw relay K1 is connected to a power supply end via the voltage transformer.

7. A pre-charging method according to claim 1, characterized in that: When the pre-charging switching unit is not working, the third end of the single-pole double-throw relay K1 is connected to the fifth end of the single-pole double-throw relay K1, and the double-pole single-throw relay K2 is disconnected from the single-pole single-throw relay K3; When the pre-charging switching unit is working, the third end of the single-pole double-throw relay K1 is connected to the fifth end of the single-pole double-throw relay K1, and the double-pole single-throw relay K2 and the single-pole single-throw relay K3 are closed.

8. A pre-charging method according to claim 1, characterized in that: The voltage setting range calculation formula across the sampling resistor R1 is: Ub=(Ua*R1) / (R1+Rx), Among them, Ub is the calculated voltage value across the sampling resistor R1, Ua is the voltage value at the power supply end, R1 is the sampling resistor, Rx is the discharge resistor at the vehicle end, and the value range of Rx is 51KΩ~2MΩ.

9. A pre-charging method according to claim 1, characterized in that: If the voltage across the sampling resistor R1 is within the set range and the direction of the main circuit AC voltage is inconsistent with the vehicle-end capacitor voltage, the main relay is closed when the direction of the main circuit AC voltage is consistent with the vehicle-end capacitor voltage.

10. A pre-charging module, characterized in that: A pre-charging system is applied, the pre-charging system includes a pre-charging switching unit, the pre-charging switching unit includes a single-pole double-throw relay K1, a rectifier bridge, a double-pole single-throw relay K2 and a single-pole single-throw relay K3, the third end of the single-pole double-throw relay K1 is connected to the power supply end, the fourth end of the single-pole double-throw relay K1 is connected to the anode of the diode D1 in the rectifier bridge, the fifth end of the single-pole double-throw relay K1 is connected to the third end of the single-pole single-throw relay K3, the fourth end of the single-pole single-throw relay K3 is connected to the cathode of the diode D3 in the rectifier bridge, the cathode of the diode D1 in the rectifier bridge is connected to the fifth end of the double-pole single-throw relay K2, the sixth end of the double-pole single-throw relay K2 and the fourth end of the double-pole single-throw relay K2 are connected to the vehicle end, the anode of the diode D3 in the rectifier bridge is connected to the third end of the double-pole single-throw relay K2, and the pre-charging module includes: An acquisition unit, the acquisition unit is used to acquire a charging signal and an AC voltage sampling value; A judgment unit, when the voltage value at both ends of the sampling resistor R1 is a constant value, judges whether the voltage value at both ends of the sampling resistor R1 is within a set range, and judges whether the direction of the main circuit AC voltage is consistent with the direction of the vehicle-end capacitor voltage; The control unit, when obtaining the charging signal, controls the third end of the single-pole double-throw relay K1 to connect to the fifth end of the single-pole double-throw relay K1, and the double-pole single-throw relay K2 and the single-pole single-throw relay K3 are closed; when the voltage value at both ends of the sampling resistor R1 is within the set range and the direction of the main circuit AC voltage is consistent with the direction of the vehicle-end capacitor voltage, the third end of the single-pole double-throw relay K1 is controlled to disconnect the fifth end of the single-pole double-throw relay K1, the double-pole single-throw relay K2 and the single-pole single-throw relay K3 are disconnected and the main relay is allowed to close.

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