Direct-current power distribution circuit with capacitive load and power distribution system

Abstract

The utility model provides a kind of DC power distribution circuit with capacitive load, it includes DC power supply, power distribution switch circuit and power distribution load, wherein power distribution switch circuit includes switch tube, control module and freewheeling device.DC power supply carries out power distribution, and power distribution switch circuit includes initial working state, intermediate working state and final working state, when power distribution switch circuit is in initial working state, the on-duty ratio of switch tube is first duty cycle;When power distribution switch circuit is in intermediate working state, the on-duty ratio of switch tube is second duty cycle;When power distribution switch circuit is in final working state, the on-duty ratio of switch tube is third duty cycle;Wherein third duty cycle is greater than second duty cycle, and second duty cycle is greater than first duty cycle, and third duty cycle is 100%.The utility model also provides a kind of power distribution system.

Description

Technical Field

[0001] This utility model relates to the field of circuits, and in particular to a DC power distribution circuit and distribution system with capacitive load. Background Technology

[0002] like Figure 1 As shown, Figure 1 For existing high-voltage DC power distribution circuits, since the capacitive loads in the power distribution generally have large-capacity input capacitors, a very large inrush current will be generated on the line when mechanical relay switches are used directly for power distribution.

[0003] To reduce the aforementioned inrush current, a resistor is typically connected in parallel across the relay switch. This allows the high-voltage DC power supply to charge the load capacitor first through the resistor. When the load capacitor voltage approaches the high-voltage DC power supply voltage, the relay switch is activated, completing the power distribution operation.

[0004] The above method can effectively reduce the inrush current, but when charging the load capacitor, the power consumption of the resistor corresponding to the relay switch is large, resulting in a large power distribution loss in the entire power distribution circuit.

[0005] Therefore, it is necessary to provide a DC power distribution circuit and system with capacitive load to solve the above-mentioned technical problems. Utility Model Content

[0006] This utility model provides a DC power distribution circuit and system with capacitive load, which effectively solves the technical problems of large starting inrush current and large distribution loss in existing power distribution circuits.

[0007] This utility model provides a DC power distribution circuit with a capacitive load, comprising: DC power supply, used to provide distribution current; A power distribution switch circuit for controlling the power distribution current and outputting the power distribution current to a power distribution load; and at least one power distribution load; The power distribution switch circuit includes: A switching transistor, used to disconnect or connect the power distribution switch circuit; A control module, connected to the switching transistor, is used to control the duty cycle of the switching transistor; and A freewheeling device is used to control the freewheeling current of the power distribution switch circuit; When the DC power supply is distributing power, the power distribution switch circuit includes an initial operating state, an intermediate operating state, and a final operating state. When the power distribution switch circuit is in the initial operating state, the duty cycle of the switching transistor is a first duty cycle; when the power distribution switch circuit is in the intermediate operating state, the duty cycle of the switching transistor is a second duty cycle; when the power distribution switch circuit is in the final operating state, the duty cycle of the switching transistor is a third duty cycle; wherein the third duty cycle is greater than the second duty cycle, the second duty cycle is greater than the first duty cycle, and the third duty cycle is 100%.

[0008] In the DC power distribution circuit of this utility model, the power distribution switch circuit includes multiple intermediate working states. The duty cycle of the switch in the intermediate working state with a longer power distribution time is greater than the duty cycle of the switch in the intermediate working state with a shorter power distribution time.

[0009] In the DC power distribution circuit described in this utility model, the first duty cycle is 1%-20%.

[0010] In the DC power distribution circuit of this utility model, the freewheeling device includes a freewheeling inductor and a freewheeling diode. The switching transistor includes an input terminal, an output terminal, and a control terminal. The input terminal of the switching transistor is connected to the positive terminal of the DC power supply. The output terminal of the switching transistor is connected to the first terminal of the freewheeling inductor. The control terminal of the switching transistor is connected to the control module. The second terminal of the freewheeling inductor is connected to the first terminal of the power distribution load. The positive terminal of the freewheeling diode is connected to the first terminal of the freewheeling inductor. The negative terminal of the freewheeling diode is connected to the second terminal of the power distribution load and the negative terminal of the DC power supply, respectively.

[0011] In the DC power distribution circuit described in this utility model, the power distribution load is a capacitive power distribution load.

[0012] In the DC power distribution circuit described in this utility model, the DC power supply further includes a voltage stabilizing capacitor, one end of which is connected to the positive terminal of the DC power supply, and the other end of which is connected to the negative terminal of the DC power supply.

[0013] In the DC power distribution circuit of this utility model, the power distribution switch circuit further includes an electronic fuse, which is connected in series with the freewheeling inductor.

[0014] In the DC power distribution circuit of this utility model, the power distribution switch circuit further includes a detection module for detecting the distribution current, distribution voltage and distribution temperature of the distribution load.

[0015] In the DC power distribution circuit described in this utility model, the DC power supply is a high-voltage DC power supply of 150V-1500V.

[0016] This utility model also provides a power distribution system with a DC power distribution circuit having capacitive loads, wherein the power distribution system includes a DC power supply, multiple power distribution switch circuits and multiple power distribution loads, wherein each power distribution switch circuit corresponds to one power distribution load; the DC power supply performs power distribution operations to the corresponding power distribution loads through the power distribution switch circuits.

[0017] Compared with the prior art, the advantages of this utility model are as follows: This utility model performs power distribution operation on capacitive loads through a power distribution switch circuit. The power distribution switch is set to an initial working state with a low duty cycle, an intermediate working state with a medium duty cycle, and a final working state with a 100% duty cycle. During the entire power distribution start-up process, the duty cycle of the switching transistor in the power distribution switch circuit gradually increases until it reaches 100%, which can effectively reduce the working current in the initial working state and reduce the device loss in the final working state. It effectively solves the technical problems of large starting inrush current and large power distribution loss in existing power distribution circuits. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of an existing high-voltage DC power distribution circuit; Figure 2 This is a schematic diagram of a specific embodiment of the DC power distribution circuit with capacitive load of this utility model. Detailed Implementation

[0019] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present utility model.

[0020] In the diagram, units with similar structures are represented by the same labels.

[0021] Please refer to Figure 2 , Figure 2 This is a schematic diagram of a specific embodiment of the DC power distribution circuit with capacitive load of this utility model. The DC power distribution circuit 20 of this embodiment includes a DC power supply 21, a power distribution switch circuit 22, and at least one power distribution load 23; wherein the DC power supply 21 is used to provide power distribution current, the power distribution switch circuit 22 is used to control the power distribution current, and output the power distribution current to the power distribution load 23.

[0022] The power distribution switch circuit 22 specifically includes a switching transistor 221, a control module 222, and a freewheeling device 223; the switching transistor 221 is used to disconnect or connect the power distribution switch circuit 22; the control module 222 is connected to the switching transistor 221 and is used to control the duty cycle of the switching transistor 221; the freewheeling device 223 is used to control the freewheeling current of the power distribution switch circuit 22.

[0023] Specifically, the freewheeling device 223 includes a freewheeling inductor 2231 and a freewheeling diode 2232. The switching transistor 221 includes an input terminal, an output terminal, and a control terminal. The input terminal of the switching transistor 221 is connected to the positive terminal of the DC power supply 21. The output terminal of the switching transistor 221 is connected to the first terminal of the freewheeling inductor 2231. The control terminal of the switching transistor 221 is connected to the control module 222. The second terminal of the freewheeling inductor 2231 is connected to the first terminal of the power distribution load 23. The positive terminal of the freewheeling diode 2232 is connected to the first terminal of the freewheeling inductor 2231. The negative terminal of the freewheeling diode 2232 is connected to the second terminal of the power distribution load 23 and the negative terminal of the DC power supply 21, respectively.

[0024] In this embodiment, the power distribution load 23 is a capacitive power distribution load, and the DC power supply 21 is a high-voltage DC power supply of 150V-1500V.

[0025] The power distribution switch circuit 22 of this embodiment includes an initial operating state when the DC power supply 21 starts distributing power (at which time the charge of the load capacitor is zero), an intermediate operating state (the charge of the load capacitor gradually increases), and a final operating state (the charge of the load capacitor is at its maximum, and the voltage across the load capacitor is approximately equal to the voltage of the DC power supply 21). In the initial operating state, the duty cycle of the switch transistor 221 is the first duty cycle; in the intermediate operating state, the duty cycle is the second duty cycle; and in the final operating state, the duty cycle is the third duty cycle.

[0026] The third duty cycle is greater than the second duty cycle, and the second duty cycle is greater than the first duty cycle. In this embodiment, in order to reduce the switching drive loss of the switching transistor 221, the third duty cycle is 100%. When the DC power supply 21 distributes power, the user can set the first duty cycle of the switching transistor 221 according to the distribution current that the distribution switch circuit 22 can accept, so that the initial distribution current of the distribution switch circuit 22 will not be too large. The first duty cycle can generally be set to 1%-20%. Under this conduction duty cycle, the distribution current will not be greater than the preset distribution current setting value (inrush current value).

[0027] Preferably, the power distribution switch circuit 22 of this embodiment may further include multiple intermediate operating states, wherein the duty cycle of the switch 221 in the intermediate operating state with a longer power distribution time is greater than the duty cycle of the switch 221 in the intermediate operating state with a shorter power distribution time. As the power distribution current charges the load capacitor, the voltage difference between the load capacitor and the DC power supply 21 will become smaller and smaller, thus the power distribution current will also become smaller and smaller. Therefore, the power distribution current can be appropriately increased by increasing the duty cycle of the switch 221. Specifically, if four intermediate operating states are set, they can be set according to the power distribution time sequence: the initial operating state with a 10% duty cycle, the first intermediate operating state with a 20% duty cycle, the second intermediate operating state with a 40% duty cycle, the third intermediate operating state with a 60% duty cycle, the fourth intermediate operating state with an 80% duty cycle, and the final operating state with a 100% duty cycle. The switching of the above operating states can be evenly switched according to the power distribution time, or it can be switched according to the magnitude of the current power distribution current to ensure that the current power distribution current is not too large.

[0028] Furthermore, in order to avoid excessive distribution current caused by control failure of the power distribution switch circuit 22, an electronic fuse 224 can also be provided on the power distribution switch circuit 22, which is connected in series with the freewheeling inductor 2231.

[0029] Furthermore, the DC power supply 21 also includes a voltage regulator capacitor 211. One end of the voltage regulator capacitor 211 is connected to the positive terminal of the DC power supply 21, and the other end of the voltage regulator capacitor 211 is connected to the negative terminal of the DC power supply 21. The voltage regulator capacitor 211 can effectively ensure the stability of the output voltage of the DC power supply 21.

[0030] In addition, the power distribution switch circuit 22 is also equipped with a detection module (not shown in the figure) for detecting the power distribution current, power distribution voltage and power distribution temperature of the power distribution load 23. This detection module can have communication function and can report the detected power distribution current, power distribution voltage and power distribution temperature in real time to realize intelligent power distribution and power distribution health management.

[0031] When the DC power supply 21 of the DC power distribution circuit 20 of this utility model starts distributing power to the load 23, the distribution switch circuit 22 is initially in the start-up state. The control module 222 sets the duty cycle of the switch transistor 221 to the first duty cycle. At this time, the voltage difference between the load capacitor and the DC power supply 21 is relatively large. To avoid a large inrush current on the large switching circuit, the first duty cycle is set relatively small, and the voltage of the load capacitor rises slowly. After a set time, when the voltage of the load capacitor rises to the first voltage setting value, or when the distribution current of the switching circuit is less than the distribution current setting value, the distribution switch circuit 22 switches to the intermediate working state. The control module 222 sets the duty cycle of the switch transistor 221 to the second duty cycle. As the voltage difference between the load capacitor and the DC power supply 21 decreases, the duty cycle of the switch transistor 221 continuously increases in order to maintain the distribution current on the switching circuit, and the voltage of the load capacitor also continuously increases. After a set time, when the voltage of the load capacitor rises to the second voltage setting value (which is equivalent to the voltage of the DC power supply 21), or when the distribution current of the switching circuit is less than the distribution current setting value (which is the final distribution current), the power distribution switch circuit 22 switches to its final operating state. The control module 222 sets the duty cycle of the switch transistor 221 to 100%. At this time, the voltage of the load capacitor is equivalent to the DC power supply voltage, and no large inrush current is generated. Moreover, the switch transistor 221 is in the normally open state, which can stably output the distribution current to the load 23, effectively reducing the distribution loss of the power distribution switch circuit 22. Users can set the switching conditions of the power distribution switch circuit 22 based on time, the voltage of the load capacitor, and / or the distribution current. However, all switching conditions are designed to ensure that the distribution current of the power distribution switch circuit 22 does not exceed the distribution current setting value. This completes the operation of the DC power distribution circuit 20 distributing power to the load 23 in this embodiment.

[0032] This utility model also relates to a power distribution system that uses the aforementioned DC power distribution circuit with capacitive loads. The power distribution system includes a DC power supply, multiple distribution switch circuits, and multiple distribution loads, with each distribution switch circuit corresponding one-to-one with a distribution load. The DC power supply distributes power to the corresponding distribution loads through the distribution switch circuits. The specific working principle of the power distribution system in this embodiment is the same as or similar to the working principle of the specific embodiment of the DC power distribution circuit described above; please refer to the relevant description of the specific embodiment of the DC power distribution circuit described above for details.

[0033] The power distribution system and DC power distribution circuit of this utility model distribute power to capacitive loads through a power distribution switch circuit. The power distribution switch is set to an initial working state with a low duty cycle, an intermediate working state with a medium duty cycle, and a final working state with a 100% duty cycle. During the entire power distribution start-up process, the duty cycle of the switching transistor in the power distribution switch circuit gradually increases until it reaches 100%, which can effectively reduce the operating current in the initial working state and reduce the device losses in the final working state. This effectively solves the technical problems of large starting inrush current and large power distribution losses in existing power distribution circuits.

[0034] In summary, although the present invention has been disclosed above with reference to preferred embodiments, the above preferred embodiments are not intended to limit the present invention. Those skilled in the art can make various modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the scope defined in the claims.

Claims

1. A DC power distribution circuit with a capacitive load, characterized in that, include: DC power supply, used to provide distribution current; A power distribution switch circuit is used to control the power distribution current and output the power distribution current to the power distribution load; and at least one power distribution load; The power distribution switch circuit includes: A switching transistor, used to disconnect or connect the power distribution switch circuit; A control module, connected to the switching transistor, is used to control the duty cycle of the switching transistor; and A freewheeling device is used to control the freewheeling current of the power distribution switch circuit; When the DC power supply is distributing power, the power distribution switch circuit includes an initial operating state, an intermediate operating state, and a final operating state. When the power distribution switch circuit is in the initial operating state, the duty cycle of the switching transistor is a first duty cycle; when the power distribution switch circuit is in the intermediate operating state, the duty cycle of the switching transistor is a second duty cycle; when the power distribution switch circuit is in the final operating state, the duty cycle of the switching transistor is a third duty cycle; wherein the third duty cycle is greater than the second duty cycle, the second duty cycle is greater than the first duty cycle, and the third duty cycle is 100%.

2. The DC power distribution circuit with capacitive load according to claim 1, characterized in that, The power distribution switch circuit includes multiple intermediate operating states. The duty cycle of the switch in the intermediate operating state with a longer power distribution time is greater than the duty cycle of the switch in the intermediate operating state with a shorter power distribution time.

3. The DC power distribution circuit with capacitive load according to claim 1, characterized in that, The first duty cycle is 1%-20%.

4. The DC power distribution circuit with capacitive load according to claim 1, characterized in that, The freewheeling device includes a freewheeling inductor and a freewheeling diode. The switching transistor includes an input terminal, an output terminal, and a control terminal. The input terminal of the switching transistor is connected to the positive terminal of the DC power supply. The output terminal of the switching transistor is connected to the first terminal of the freewheeling inductor. The control terminal of the switching transistor is connected to the control module. The second terminal of the freewheeling inductor is connected to the first terminal of the power distribution load. The positive terminal of the freewheeling diode is connected to the first terminal of the freewheeling inductor. The negative terminal of the freewheeling diode is connected to the second terminal of the power distribution load and the negative terminal of the DC power supply, respectively.

5. The DC power distribution circuit with capacitive load according to claim 1, characterized in that, The power distribution load is a capacitive power distribution load.

6. The DC power distribution circuit with capacitive load according to claim 1, characterized in that, The DC power supply also includes a voltage-stabilizing capacitor, one end of which is connected to the positive terminal of the DC power supply, and the other end of which is connected to the negative terminal of the DC power supply.

7. The DC power distribution circuit with capacitive load according to claim 4, characterized in that, The power distribution switch circuit also includes an electronic fuse, which is connected in series with the freewheeling inductor.

8. The DC power distribution circuit with capacitive load according to claim 1, characterized in that, The power distribution switch circuit also includes a detection module for detecting the power distribution current, power distribution voltage, and power distribution temperature of the power distribution load.

9. The DC power distribution circuit with capacitive load according to claim 1, characterized in that, The DC power supply is a high-voltage DC power supply of 150V-1500V.

10. A power distribution system using a DC power distribution circuit with a capacitive load as described in any one of claims 1-9, characterized in that, The power distribution system includes a DC power supply, multiple power distribution switch circuits, and multiple power distribution loads, with each power distribution switch circuit corresponding to one of the power distribution loads; the DC power supply performs power distribution operations to the corresponding power distribution loads through the power distribution switch circuits.

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