Current detection and protection circuit of DC-DC direct charging device

Abstract

The utility model discloses a current detection and protection circuit of a DC-DC direct charging device, and relates to the technical field of current detection. The device comprises a detection module used for collecting a direct current signal and converting the direct current signal into a digital signal; the processing module processes the digital signal from the detection module through the isolation module and controls the output power; and the voltage stabilizing module provides a direct-current stabilized power supply for the detection module, the isolation module and the processing module. The current detection and protection circuit of the DC-DC direct charging device has the beneficial effects that the communication isolation circuit realizes digital communication electrical isolation between a high-voltage side and a low-voltage side; the detection module converts the high-voltage direct current into an accurate digital signal and transmits the accurate digital signal to the digital signal processing circuit; the processing module carries out digital processing and real-time analysis on the signals output by the sensing module, carries out output power control according to the power distribution condition of the direct charging system, judges overload and short circuit, and carries out protection control on faults.

Description

TECHNICAL FIELD

[0001] The utility model relates to current detection technical field especially a current detection and protection circuit of DC-DC direct charging device. BACKGROUND

[0002] In the DC-DC direct charging system of photovoltaic, the accurate detection of current is crucial. The current detection circuit can monitor the change of system current in real time, thereby distributing the output power of DC-DC direct charging system, controlling the efficiency of photovoltaic system in the most reasonable interval, and preventing the occurrence of faults such as overload and short circuit.

[0003] The utility model patent aims at providing a DC-DC current detection circuit with reasonable design, stable performance, high detection accuracy and isolation function to meet the actual needs of direct charging system. SUMMARY

[0004] This part aims to outline some aspects of the embodiments of the utility model and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this part and the abstract of the specification and the utility model name to avoid obscuring the purpose of this part, the abstract of the specification and the utility model name, and such simplifications or omissions cannot be used to limit the scope of the utility model.

[0005] Therefore, the problem to be solved by the utility model is how to detect current with isolation function and power output function.

[0006] To solve the above technical problems, the utility model provides the following technical scheme: a current detection and protection circuit of DC-DC direct charging device, comprising a detection module for collecting direct current signals and converting them into digital signals; a processing module for processing digital signals from the detection module through an isolation module and controlling output power; and a voltage stabilizing module for providing direct current stabilized power supply for the detection module, the isolation module and the processing module.

[0007] As a preferred scheme of the current detection and protection circuit of DC-DC direct charging device, the detection module comprises a linear Hall current sensor, the linear Hall current sensor collects linear voltage signals and sends them to the inverting input end of an operational amplifier through a VOUT pin, the output end of the operational amplifier is connected with a +IN pin of a digitizing chip, and the digitizing chip outputs digitized current digital signals through an ISP communication interface.

[0008] As a preferred scheme of the current detection and protection circuit of DC-DC direct charging device, a reference voltage adjusting resistor is arranged on the line from the linear Hall current sensor to the inverting input end of the operational amplifier.

[0009] As the preferred scheme of the current detection and protection circuit of the DC-DC direct charging device, the digital chip is further connected with an amplifier gain adjusting resistor.

[0010] As the preferred scheme of the current detection and protection circuit of the DC-DC direct charging device, an overvoltage protection diode is arranged on an input voltage line of the digital chip.

[0011] As the preferred scheme of the current detection and protection circuit of the DC-DC direct charging device, the isolation module comprises a high-voltage isolation power supply module and a digital signal isolation module; the high-voltage isolation power supply module comprises a high-voltage isolation power supply and a first low-dropout regulator, the high-voltage isolation power supply is used for 5V DC voltage isolation, and the high-voltage isolation power supply is further connected with a first filter capacitor and a second filter capacitor; and the first low-dropout regulator converts 5V power supply into 3.3V power supply.

[0012] As the preferred scheme of the current detection and protection circuit of the DC-DC direct charging device, the digital signal isolation module comprises a digital signal isolation module chip, which is used for isolating ISP digital signals from the digital chip from the processing module.

[0013] As the preferred scheme of the current detection and protection circuit of the DC-DC direct charging device, the processing module comprises a digital signal processor, which is used for analyzing ISP digital signals from the digital chip to obtain actual current of the direct charging system, and controlling output power of the direct charging system according to CMS load of the direct charging system through the first field effect tube and the second field effect tube.

[0014] As the preferred scheme of the current detection and protection circuit of the DC-DC direct charging device, the voltage stabilizing module supplies the digital signal processor and the second low-dropout regulator with 5V DC power supply after reducing the 5V DC power supply to 3.3V through a voltage reduction and voltage stabilization chip; and the second low-dropout regulator converts 3.3V into a reference voltage.

[0015] As the preferred scheme of the current detection and protection circuit of the DC-DC direct charging device, the voltage stabilizing module further supplies the high-voltage isolation power supply with 5V DC power supply through the second inductor.

[0016] The DC-DC direct charging device's current detection and protection circuit has the beneficial effects that: the communication isolation circuit realizes digital communication electrical isolation between the high-voltage side and the low-voltage side; the detection module converts the high-voltage direct current into accurate digital signals and transmits the digital signals to the digital signal processing circuit; the processing module performs digital processing and real-time analysis on the signals output by the sensing module, controls the output power according to the power distribution of the direct charging system, and judges overload and short circuit, and protects and controls the fault. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical scheme of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiment description, and obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained according to these drawings without creative labor. Among them:

[0018] Figure 1 The embodiment provided by the present application is a whole schematic diagram of the current detection and protection circuit of the DC-DC direct charging device;

[0019] Figure 2 The detection module circuit schematic diagram of the present application;

[0020] Figure 3 The isolation module circuit schematic diagram of the present application;

[0021] Figure 4 The processing module circuit schematic diagram of the present application;

[0022] Figure 5 The voltage stabilizing module circuit schematic diagram of the present application; DETAILED DESCRIPTION

[0023] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application will be described in detail below with reference to the drawings of the specification.

[0024] In the following description, many specific details are set forth in order to provide a thorough understanding of the present application, but the present application can also be implemented in other ways different from the description, and those skilled in the art can make similar generalization without departing from the connotation of the present application, therefore the present application is not limited by the specific embodiments disclosed below.

[0025] Second, the utility model in combination with the schematic diagram is described in detail, in the detailed description of the utility model embodiment, for the convenience of description, the section view of the device structure will be partially enlarged without the general proportion, and the schematic diagram is only an example, which should not limit the scope of the utility model protection here. In addition, the three-dimensional spatial dimensions of length, width and depth should be included in actual production.

[0026] Thirdly, the "one embodiment" or "embodiment" referred to herein means that the specific features, structures or characteristics can be included in at least one implementation of the utility model. "In one embodiment" appearing in different places in the specification does not mean the same embodiment, nor is it an embodiment that is independent of or selectively excludes other embodiments.

[0027] Embodiment 1, refer to Figures 1 to 5 The embodiment provides a current detection and protection circuit of a DC-DC direct charging device, which comprises a detection module 100, a processing module 300 and a voltage stabilizing module 400.

[0028] The communication isolation circuit realizes the digital communication electrical isolation between the high-voltage side and the low-voltage side; the detection module converts the high-voltage direct current into accurate digital signals and transmits the digital signals to the digital signal processing circuit; the processing module performs digital processing and real-time analysis on the signals output by the sensing module, controls the output power according to the power distribution of the direct charging system, judges the overload and short circuit, and protects and controls the fault.

[0029] Embodiment 2, refer to Figure 2 The second embodiment of the utility model is different from the first embodiment in that: the embodiment provides a detection module 100, the detection module 100 comprises a linear Hall current sensor U11, the linear Hall current sensor U11 collects a linear voltage signal, and a VOUT pin is transmitted to an inverting input end of an operational amplifier U12, an output end of the operational amplifier U12 is connected with a +IN pin of a digitizing chip U1, and the digitizing chip U1 outputs a digitized current digital signal through an ISP communication interface.

[0030] A reference voltage adjusting resistor R24 is arranged on a line from the linear Hall current sensor U11 to the inverting input end of the operational amplifier U12, and the maximum resistance is 50kΩ.

[0031] The digitizing chip U1 is also connected with an amplifier gain adjusting resistor R2.

[0032] The overvoltage protection diodes, namely D1 and D2, are arranged on the input voltage line of the digitization chip U1.

[0033] The 15th, 13th, 12th and 11th pins of the digitization chip U1 are used as the ISP communication interface to output the digitized current digital signal.

[0034] Embodiment 3, refer to Figure 3 The third embodiment of the utility model differs from the first two embodiments in that the embodiment provides an isolation module 200, the isolation module 200 comprising a high-voltage isolation power module 201 and a digital signal isolation module 202; the high-voltage isolation power module 201 comprising a high-voltage isolation power supply H2 and a first low-dropout regulator LDO1, the high-voltage isolation power supply H2 being used for 5V DC-DC voltage isolation, the high-voltage isolation power supply H2 further comprising a first filter capacitor C32 and a second filter capacitor C33, and the first low-dropout regulator LDO1 converting 5V power supply into 3.3V power supply.

[0035] The digital signal isolation module 202 comprises a digital signal isolation module chip U3, which is used for isolating the ISP digital signal from the digitization chip U1 from the processing module 300.

[0036] The high-voltage isolation power supply H2 realizes 5V DC-DC voltage isolation, the isolated voltage reaching 3kV, the current being 500mA, and the power supply power being 2.5W; the C32 and C33 serve as filter capacitors to reduce power supply ripple, R5 serves as a load to stabilize the output of H2, LDO1 serves as a low-dropout regulator to convert 5V power supply into stable 3.3V power supply, and U3 serves as a digital signal magnetic isolation circuit to isolate the ISP digital signal from U1 from the digital processing circuit, the isolation level being 3kV, and C25, C26, C27 and C28 serving as decoupling capacitors to enhance the working stability of U3 and avoid data transmission errors.

[0037] Embodiment 4, refer to Figure 4 The fourth embodiment of the utility model differs from the first three embodiments in that the embodiment provides a processing module 300, the processing module 300 comprising a digital signal processor MCU, which is used for analyzing the ISP digital signal from the digitization chip U1 to obtain the actual current of the direct charging system, and controlling the output power of the direct charging system through the first field effect tube Q1 and the second field effect tube Q2 according to the CMS load of the direct charging system.

[0038] The MCU is responsible for digital signal processing, and the digital current signal from the current sampling circuit is analyzed by the MCU to obtain the actual current of the direct charging system, and the dynamic charging power is adjusted according to the CMS load setting of the direct charging system, and the current change is judged, if the current reaches the overload threshold, the MCU controls the output power of the direct charging system through the field effect tubes Q1 and Q2, when the load signal from the CMS indicates that the current load is light, the MCU increases the current of the direct charging according to the configured load curve through Q2, and more power is distributed to the charging system, when the load signal from the CMS indicates that the current load is increased, the MCU reduces the current of the direct charging or stops the direct charging according to the configured load curve through Q2.

[0039] Embodiment 5, refer to Figure 5 The fifth embodiment of the utility model is different from the first four embodiments, which provides a voltage stabilizing module 400, the voltage stabilizing module 400 supplies the digital signal processor MCU and the second low dropout regulator U8 with 5V DC power after reducing the 5V DC power to 3.3V through the voltage reduction and voltage stabilization chip U10, and the second low dropout regulator U8 converts the 3.3V into a reference voltage.

[0040] The voltage stabilizing module 400 also supplies the high-voltage isolation power supply H2 with 5V DC power through the second inductor L2.

[0041] The high-voltage isolation power supply H2 realizes 5V-5V DC voltage isolation output, and provides the U1, U11 and U12 of the current collection circuit with stable voltage, ensuring the stable operation of the current collection circuit under 3kV high-voltage isolation.

[0042] It is important to note that the construction and arrangements of the application shown in the various exemplary embodiments are illustrative only. Although only a few embodiments have been described in detail in this disclosure, those skilled in the art who review this disclosure will readily appreciate that many modifications can be made to the embodiments without departing from the novel teachings and advantages of the subject matter described herein (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, locations, and the like). For example, the elements shown as integrally formed can be constructed of multiple parts or elements, the position of elements can be reversed or otherwise varied, and the nature or number of elements or positions can be modified or changed. Accordingly, all such modifications are intended to be included within the scope of the present inventive subject matter. The order or sequence of any process or method steps can be varied or re-sequenced without departing from the subject matter described herein. Any "open / closed" claims are intended to encompass the structure described herein, and not just the structure equivalent, but also the equivalent structure. Other substitutions, modifications, changes, and omissions can be made in the design, operating conditions, and arrangement of the exemplary embodiments without departing from the scope of the present inventive subject matter. Accordingly, the present inventive subject matter is not limited to particular embodiments described, but extends to any inventive subject matter within the scope of the appended claims.

[0043] Furthermore, in order to provide a concise description of exemplary embodiments, not all features of an actual implementation can be described (i.e., those pertaining to the best mode for carrying out the inventive subject matter currently under consideration, or those that are not relevant to the implementation of the inventive subject matter).

[0044] It is to be understood that the development of the exemplary embodiments of this application can not be limited to the particular implementation described above, but can include any number of variations, modifications, or equivalents to the described implementations. For example, the order of the steps can be varied, or some steps can be omitted, or some steps can be performed in parallel. It is further understood that the use of relational terms such as first and second, and the like, if any, are used solely to distinguish one from another entity or action without necessarily implying a required order of such entities or actions or the necessity of such entities or actions.

[0045] It should be noted that the above examples are intended to be illustrative only and not limiting of the technical solutions of the present application, and although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present application, and all should be included in the scope of the claims of the present application.

Claims

1. A current detection and protection circuit for a DC-DC direct charging device, characterized by: The application relates to a direct-current charging system, which comprises the following modules: a detection module (100) for collecting a direct-current signal and converting the direct-current signal into a digital signal; a processing module (300) for processing the digital signal from the detection module (100) through an isolation module (200) and controlling output power; a voltage stabilizing module (400) for providing a direct-current stabilized power supply for the detection module (100), the isolation module (200) and the processing module (300).

2. The current detection and protection circuit for DC-DC direct charging device according to claim 1, characterized in that: The detection module (100) comprises a linear Hall current sensor (U11) for collecting a linear voltage signal and transmitting the linear voltage signal to an inverting input end of an operational amplifier (U12) through a VOUT pin, wherein an output end of the operational amplifier (U12) is connected with a +IN pin of a digitizing chip (U1), and the digitizing chip (U1) outputs a digitized current digital signal through an ISP communication interface.

3. The current detection and protection circuit for DC-DC direct charging device according to claim 2, characterized in that: A reference voltage adjusting resistor (R24) is arranged on a line from the linear Hall current sensor (U11) to the inverting input end of the operational amplifier (U12).

4. The current detection and protection circuit for DC-DC direct charging device according to claim 3, characterized in that: The digitizing chip (U1) is also connected with an amplifier gain adjusting resistor (R2).

5. The current detection and protection circuit for DC-DC direct charging device according to claim 4, characterized in that: An overvoltage protection diode is arranged on an input voltage line of the digitizing chip (U1).

6. The current detection and protection circuit for a DC-DC direct charging device according to claim 5, wherein: The isolation module (200) comprises a high-voltage isolation power supply module (201) and a digital signal isolation module (202). The high-voltage isolation power supply module (201) comprises a high-voltage isolation power supply (H2) and a first low-dropout regulator (LDO1), the high-voltage isolation power supply (H2) is used for DC-DC voltage isolation of 5V, the high-voltage isolation power supply (H2) is also connected with a first filter capacitor (C32) and a second filter capacitor (C33), and the first low-dropout regulator (LDO1) converts 5V power supply into 3.3V power supply.

7. The current detection and protection circuit for a DC-DC direct charging device according to claim 6, characterized in that: The digital signal isolation module (202) comprises a digital signal isolation module chip (U3) for isolating ISP digital signals from the digitizing chip (U1) from the processing module (300).

8. The current detection and protection circuit of a DC-DC direct charging device according to any one of claims 1-7, characterized in that: The processing module (300) comprises a digital signal processor (MCU) for analyzing the ISP digital signals from the digitizing chip (U1) to obtain actual current of a direct charging system, and controlling output power of the direct charging system through a first field effect transistor (Q1) and a second field effect transistor (Q2) according to a CMS load of the direct charging system.

9. The current detection and protection circuit for a DC-DC direct charging device according to claim 8, wherein: The voltage stabilizing module (400) supplies 3.3V to the digital signal processor (MCU) and a second low-dropout regulator (U8) after reducing 5V direct-current power supply through a step-down voltage stabilizing chip (U10). The second low-dropout regulator (U8) converts 3.3V into a reference voltage.

10. The current detection and protection circuit for a DC-DC direct charging device according to claim 9, wherein: The voltage stabilizing module (400) also supplies 5V direct-current power supply to the high-voltage isolation power supply (H2) through a second inductor (L2).

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