Circuit and device for direct current pre-charging test

Abstract

The utility model relates to a circuit and a device used for a direct current pre-charging test, the circuit comprises a charging and discharging control circuit, the charging and discharging control circuit comprises a capacitor module, an intelligent direct current voltmeter and a second contactor, the capacitor module is used for simulating a direct current bus capacitor load, and the intelligent direct current voltmeter is used for controlling the intelligent direct current voltmeter. The intelligent direct current voltmeter is connected with the capacitor module in parallel, one end of the second contactor is connected with the pre-charging resistor, and the other end of the second contactor is connected with the capacitor module. Function conversion control of three modes of direct charging, pre-charging and discharging is realized through the change-over switch, the operation is convenient, safe and reliable, and the working efficiency is improved; circuits and devices are integrated in the box body and are controlled by an external change-over switch, so that the operation safety is improved; and simple and reliable electrical switch control is adopted, so that the direct current pre-charging test function of the battery management control system is realized on the basis of low cost.

Description

Technical Field

[0001] This utility model relates to the field of DC precharge testing technology, specifically to a circuit and device for DC precharge testing. Background Technology

[0002] Currently, when verifying the DC precharge function of a battery management unit (BMU), the lack of a suitable DC bus capacitor to simulate the load makes it impossible to effectively reproduce and verify the precharge function. Directly using inverter products for testing may lead to precharge function defects due to design flaws, potentially causing equipment failure during use, resulting in testing disruptions and wasted resources. The market lacks dedicated equipment for verifying the DC precharge function of BMUs. The common practice is to temporarily set up a test environment and complete the test by connecting series capacitors. However, this approach is not only time-consuming and labor-intensive, but also requires introducing impedance and adding switches to control the circuit state for both the charging and discharging processes, increasing complexity and workload. Utility Model Content

[0003] To address the aforementioned problems, this utility model provides a circuit for DC precharge testing, including a charge / discharge control circuit. The charge / discharge control circuit includes a capacitor module, a smart DC voltmeter, and a second contactor. The capacitor module is used to simulate a DC bus capacitor load. The smart DC voltmeter is connected in parallel with the capacitor module. One end of the second contactor is connected to a precharge resistor, and the other end is connected to the capacitor module.

[0004] Based on the above scheme, a power supply control circuit is also included. The power supply control circuit includes a changeover switch, a DC power supply and a contactor coil. One end of the changeover switch is connected to the contactor coil and the other end is connected to the DC power supply. The changeover switch is used to switch between three working modes: direct charging, pre-charging and discharging.

[0005] Based on the above scheme, a DC voltage acquisition and control circuit is also included. The DC voltage acquisition and control circuit includes an electronic timer, and the intelligent DC voltmeter also includes control contacts, which control the start and stop of the electronic timer.

[0006] Based on the above scheme, the charging and discharging control circuit further includes a first contactor, a third contactor, a discharge resistor, and a first fuse. One end of the first contactor is connected to the first fuse, and the other end is connected to the capacitor module. One end of the third contactor is connected to the capacitor module, and the other end is connected to the discharge resistor.

[0007] Based on the above scheme, the power supply control circuit also includes an LED indicator light, which is connected in parallel with the contactor coil and is used to display the operating mode of the circuit.

[0008] Based on the above scheme, the contactor coil includes a first contactor coil, a second contactor coil, and a third contactor coil. The first contactor coil, the second contactor coil, and the third contactor coil are respectively connected to a switching switch, and the switching switch controls the contactor coil to be energized and de-energized.

[0009] This application also provides a device for DC precharge testing, which uses the circuit for DC precharge testing described above. The front panel of the device integrates a switch, indicator lights, an intelligent DC voltmeter display unit, a timer display unit, a timer reset button, and a precharge voltage measurement port.

[0010] Based on the above scheme, the device adopts a 19-inch chassis shell, the front panel is equipped with tabs, the side panel of the chassis is equipped with embedded handles, and the rear panel integrates a capacitor capacity expansion port and an AC power supply socket with switch and light.

[0011] Based on the above scheme, the capacitor module includes an electrolytic capacitor, a fixing screw, and a supporting and clamping bakelite board, with the electrolytic capacitor and the fixing screw located between the supporting and clamping bakelite board.

[0012] Compared with the prior art, the beneficial effects of this utility model are as follows: It achieves functional switching control between direct charging, pre-charging, and discharging modes through a selector switch, making operation convenient, safe, and reliable, and improving work efficiency; the circuits and components are integrated inside the housing and controlled by an external selector switch, thereby improving operational safety; a smart DC voltmeter monitors the pre-charging voltage and outputs upper and lower voltage limits to control the electronic timer, realizing the timing function of the pre-charging process, enabling real-time monitoring of the pre-charging status and facilitating the detection of test anomalies; and it employs simple and reliable electrical switch control, achieving the DC pre-charging test function of the battery management control system at a low cost. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the charging and discharging control circuit structure of this utility model;

[0014] Figure 2 This is a schematic diagram of the power supply control circuit structure of this utility model;

[0015] Figure 3 This is a schematic diagram of the DC voltage acquisition and control circuit structure of this utility model;

[0016] Figure 4 This is a schematic diagram of the front panel structure of the device of this utility model;

[0017] Figure 5 This is a schematic diagram of the rear panel structure of the device of this utility model;

[0018] Figure 6This is a schematic diagram of the capacitor module structure of this utility model. Detailed Implementation

[0019] The present invention will be further described below with reference to the accompanying drawings:

[0020] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in this utility model can be understood according to the specific circumstances.

[0021] This application provides a device for DC precharge testing, which is used as a supporting experimental device for DC precharge simulation verification of laboratory battery management control devices. It can effectively improve work efficiency and safety, and has the ability to expand the capacity.

[0022] The core of the device is a circuit for DC precharge testing. The circuit includes a charge and discharge control circuit, which includes a capacitor module, a smart DC voltmeter, and a second contactor KM2. The capacitor module is used to simulate a DC bus capacitive load. In one embodiment, the capacitor module is a large-capacity capacitor module composed of multiple electrolytic capacitors (DC450V 4700uF), connected in a 4-series-3-parallel configuration, with a total withstand voltage of up to 1800V and a capacity of 3525uF, used to simulate a DC bus capacitive load in actual applications.

[0023] Furthermore, to enhance the adaptability and scalability of the device, the rear panel of the DC precharge test device integrates a capacitor capacity expansion port 8, which supports adjusting the capacitor capacity according to different precharge bus capacity requirements.

[0024] like Figure 1 The intelligent DC voltmeter is connected in parallel with the capacitor module, enabling real-time monitoring of the pre-charge voltage and providing upper and lower voltage limit output control. The second contactor KM2 is connected at one end to the pre-charge resistor R2 and at the other end to the capacitor module, controlling the current path during pre-charging. The first contactor KM1 is connected at one end to the first fuse F1 and at the other end to the capacitor module; F1 ensures safe operation in working mode. The third contactor KM3 is connected at one end to the capacitor module and at the other end to the discharge resistor R1, helping to release energy from the capacitor in discharge mode.

[0025] Furthermore, the charge and discharge control circuit also includes a second fuse F2, one end of which is connected to the first contactor and the second contactor respectively, and the other end is connected to the third contactor.

[0026] Preferably, the discharge resistor R1 is a high-power aluminum-cased resistor to ensure the safe release of energy from the capacitor.

[0027] The circuit also includes a power supply control circuit and a DC voltage acquisition and control circuit. The power supply control circuit includes a changeover switch K1, a DC power supply and a contactor coil. One end of the changeover switch is connected to the contactor coil and the other end is connected to the DC power supply. The changeover switch is used to switch between three working modes: direct charging, pre-charging and discharging.

[0028] like Figure 2 As shown, the AC / DC switching power supply converts alternating current (AC) to 24V direct current (DC), providing a stable power supply for the high-voltage DC contactor coil. The contactor coil includes a first contactor coil, a second contactor coil, and a third contactor coil, each controlling the operation of its corresponding contactor. These coils are connected to a changeover switch, which controls the energizing state. LED indicator lights are connected in parallel with the contactor coils to display the current operating mode (direct charging, pre-charging, or discharging). Specifically, the LED indicator lights include a first LED indicator LED1, a second LED indicator LED2, and a third LED indicator LED3, which are connected in parallel with the first, second, and third contactor coils, respectively.

[0029] Furthermore, the power supply control circuit also includes a circuit breaker QF1, which is a 1P+N single-pole wide-range miniature circuit breaker, that is, a small circuit breaker with single-pole and neutral line protection, which can prevent damage to internal components caused by abnormal external power supply; in an emergency, the power supply to the entire device can be quickly cut off by manual operation, thereby improving the safety of the system.

[0030] The DC voltage acquisition and control circuit includes an electronic timer for recording the cumulative time of the pre-charge process. The intelligent DC voltmeter also includes control contacts, which control the start and stop of the electronic timer. When pre-charging begins, KM1 is energized, control contact Kv1-1 closes, and the electronic timer starts counting; when the voltage reaches the preset value, control contact Kv1-2 opens, and the electronic timer stops counting.

[0031] like Figure 3 As shown, the electronic timer is connected in sequence to the first control contact Kv1-1 and the second control contact Kv1-2 to form a circuit; at the same time, the electronic timer is also connected to the zeroing button K2. When K2 is closed, the electronic timer is zeroed.

[0032] The device for DC precharge testing provided in this application employs the circuit for DC precharge testing described above, such as... Figure 4 and Figure 5As shown, the device uses a 19-inch chassis shell, which is easy to integrate into a server rack. The front panel is equipped with tabs, and the side is equipped with recessed handles 7 for easy handling and moving of equipment.

[0033] The front panel of the device integrates a selector switch 6, indicator lights 5, a smart DC voltmeter display unit 1, a timer display unit 3, a timer reset button 4, and a precharge voltage measurement port 2. The selector switch is used to select direct charging, precharge, discharging mode, or stop working mode; three LED indicators show the status of the current working mode; the smart DC voltmeter display unit displays the voltage in real time, and the timer display unit displays the accumulated precharge time; the timer reset button is used to reset the timer; the precharge voltage measurement port provides external monitoring of the voltage signal through a safety 4mm banana plug.

[0034] Furthermore, the precharge voltage measurement port 2 includes two ports, DC+ and DC-. During the precharge process, these two ports are used to connect to an external power supply or load to charge or discharge the capacitor module. At the same time, these two ports also serve as access points for voltage sampling, allowing the smart DC voltmeter to monitor the voltage changes across the capacitor module in real time.

[0035] The rear panel integrates a capacitor capacity expansion port 8 and an AC power supply socket with switch and indicator light 9. The capacitor capacity expansion port supports adjusting the capacitor capacity according to different pre-charge bus capacity requirements; the AC power supply socket with switch and indicator light can provide working power to the entire test device and has an indicator light to show whether the socket is powered on, ensuring normal operation of the equipment.

[0036] like Figure 6 As shown, the capacitor module includes an electrolytic capacitor 10, a fixing screw 11, and a supporting and clamping bakelite board 12. The electrolytic capacitor and the fixing screw are located between the supporting and clamping bakelite board to ensure stable installation of the electrolytic capacitor.

[0037] Furthermore, this application can be expressed by the formula T=RC*Ln[(V bat -V0) / (V bat -V pre Calculate the theoretical pre-charge time and verify it by comparing it with the actual time. Where R is the resistance value of the pre-charge resistor, C represents the total capacitance value of the DC bus that needs to be pre-charged, and V... bat V0 is the initial voltage across the capacitor when charging begins. pre The target precharge voltage is the voltage level that the capacitor is expected to reach during the precharge process.

[0038] The following is the specific workflow of the device in this application:

[0039] Pre-charge mode: Before formal charging, the capacitor module is slowly charged via a pre-charging resistor to avoid instantaneous high current surges. Select "Pre-charge" mode via the switch on the front panel. At this time, the high-voltage DC contactor (second contactor) closes, connecting the pre-charging resistor to the circuit and initiating pre-charging of the capacitor module. A smart DC voltmeter monitors the voltage across the capacitor in real time and displays it on the smart DC voltmeter display unit on the front panel. The control contacts inside the smart DC voltmeter close, triggering the electronic timer to start timing. When the capacitor voltage reaches the preset target voltage V... pre Then, the pre-charge operation is stopped. At this time, the control contacts of the intelligent DC voltmeter open, the electronic timer stops timing, and records the time of the entire pre-charge process.

[0040] Direct charging mode: Select "Direct Charging" mode via the switch on the front panel. At this time, the high-voltage DC contactor (first contactor) closes, directly connecting to the power supply to charge the capacitor module. The intelligent DC voltmeter monitors the voltage across the capacitor in real time and displays it on the intelligent DC voltmeter display unit on the front panel. Since direct charging mode usually does not require precise time control, the electronic timer will not start. When the capacitor voltage reaches the set target voltage, the power supply will be manually or automatically cut off to end the charging process.

[0041] Discharge Mode: After pre-charging or direct charging is completed, the energy stored in the capacitor is safely released. Select the "Discharge" mode by switching on the front panel. At this time, the high-voltage DC contactor (third contactor) closes, connecting the discharge resistor to the circuit and starting to discharge the capacitor module. The intelligent DC voltmeter continues to monitor the voltage across the capacitor and displays it on the intelligent DC voltmeter display unit on the front panel. After the discharge is completed, manually or automatically disconnect the discharge circuit to end the discharge process.

[0042] The foregoing has shown and described the basic principles and main features of this utility model. It is obvious to those skilled in the art that this utility model is not limited to the details of the above exemplary embodiments. Therefore, the embodiments should be regarded as exemplary and non-limiting. The scope of this utility model is defined by the appended claims rather than the foregoing description. Therefore, it is intended to include all changes that fall within the meaning and scope of the equivalents of the claims within this utility model.

[0043] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A circuit for direct current pre-charge testing, characterized by, The device includes a charge / discharge control circuit, which comprises a capacitor module, a smart DC voltmeter, and a second contactor. The capacitor module is used to simulate a DC bus capacitor load. The smart DC voltmeter is connected in parallel with the capacitor module. One end of the second contactor is connected to a pre-charge resistor, and the other end is connected to the capacitor module.

2. A circuit for DC pre-charge testing according to claim 1, characterized in that, It also includes a power supply control circuit, which includes a changeover switch, a DC power supply and a contactor coil. One end of the changeover switch is connected to the contactor coil and the other end is connected to the DC power supply. The changeover switch is used to switch between three working modes: direct charging, pre-charging and discharging.

3. A circuit for DC pre-charge testing according to claim 1, wherein, It also includes a DC voltage acquisition and control circuit, which includes an electronic timer. The intelligent DC voltmeter also includes control contacts that control the start and stop of the electronic timer.

4. The circuit for DC pre-charge testing of claim 1, wherein, The charging and discharging control circuit further includes a first contactor, a third contactor, a discharge resistor, and a first fuse. One end of the first contactor is connected to the first fuse, and the other end is connected to the capacitor module. One end of the third contactor is connected to the capacitor module, and the other end is connected to the discharge resistor.

5. A circuit for DC pre-charge testing according to claim 2, wherein, The power supply control circuit also includes an LED indicator light, which is connected in parallel with the contactor coil and is used to display the circuit's operating mode.

6. A circuit for DC pre-charge testing according to claim 2, wherein, The contactor coil includes a first contactor coil, a second contactor coil, and a third contactor coil. The first contactor coil, the second contactor coil, and the third contactor coil are respectively connected to a switching switch, and the switching switch controls the contactor coil to be energized or de-energized.

7. An apparatus for direct current pre-charge testing, characterized by, The circuit for DC precharge testing as described in any one of claims 1-6 is used, and the front panel of the device integrates a switching switch (6), an indicator light (5), an intelligent DC voltmeter display unit (1), a timer display unit (3), a timer reset button (4), and a precharge voltage measurement port (2).

8. A device for DC pre-charge testing according to claim 7, characterized in that, The device uses a 19-inch chassis shell, the front panel is equipped with tabs, the side panel of the chassis is equipped with an embedded handle (7), and the rear panel integrates a capacitor capacity expansion port (8) and an AC power supply socket with switch and light (9).

9. A device for DC pre-charge testing as defined in claim 7, wherein, The capacitor module includes an electrolytic capacitor (10), a fixing screw (11), and a supporting and clamping bakelite board (12), with the electrolytic capacitor (10) and the fixing screw (11) located between the supporting and clamping bakelite board (12).

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