Solid state circuit breaker

Abstract

The utility model relates to a solid-state circuit breaker, which is characterized by comprising an input end connected to an anode and a cathode of a power supply; the isolating switch is connected in series in the main loop and is connected to the positive pole of the power supply; the power electronic switch is connected in series in the main loop and is connected in series with the isolating switch; and a controller configured to receive an input voltage of the power supply, a voltage to ground of a positive electrode of the power supply, and a downstream resistance to ground value of the downstream resistance to ground of the downstream resistance to ground, and control whether to disable the power electronic switch. Therefore, upstream insulation impedance abnormity can be recognized in advance, whether the electronic power switch is forbidden or not is controlled, the cost is low, and potential safety hazards can be avoided.

Description

Technical Field

[0001] This utility model relates to a solid-state circuit breaker, and more specifically, to a DC solid-state circuit breaker capable of performing insulation detection. Background Technology

[0002] For IT systems, by detecting the insulation resistance of the power supply line to the protective earth (PE), construction personnel or intelligent power supply equipment can promptly detect and avoid potential electrical safety problems (electric shock accidents or electrical fires) caused by insulation aging, moisture, mechanical damage, etc.

[0003] With the widespread application of power electronic equipment, solid-state circuit breakers capable of short-circuit protection at the μs (microsecond) level are increasingly being used in power supply and distribution systems. However, conventional DC solid-state circuit breakers either lack insulation detection capabilities or perform insulation detection by connecting a relay circuit in series with ground. The insulation of the relay connected in series with ground must be considered, which often results in relatively high costs.

[0004] Therefore, a simple and low-cost solution for insulation testing of DC solid-state circuit breakers is needed. Utility Model Content

[0005] This utility model relates to a solid-state circuit breaker, characterized in that it includes: an input terminal connected to the positive and negative terminals of a power supply; a disconnecting switch connected in series in the main circuit and connected to the positive terminal of the power supply; a power electronic switch connected in series in the main circuit and connected in series with the disconnecting switch; and a controller configured to receive the input voltage of the power supply, the voltage to ground of the positive terminal of the power supply, and the downstream resistance value to ground of the downstream resistor, and to control whether to disable the power electronic switch.

[0006] In one example, the voltage to ground of the positive terminal of the power supply includes: a first voltage to ground in the open state of the solid-state circuit breaker and a second voltage to ground in the standby state of the solid-state circuit breaker.

[0007] In one example, the controller is also configured to: determine the upstream insulation impedance based on the voltage division relationship between the power supply input voltage, the first voltage to ground, the second voltage to ground, and the downstream resistance to ground; and determine an upstream insulation impedance anomaly when the upstream insulation impedance is below a threshold.

[0008] In one example, the controller is also configured to disable the power electronic switch when an abnormality in the upstream insulation impedance is determined.

[0009] In one example, the downstream-to-ground resistor is an equivalent downstream-to-ground resistor downstream of the disconnecting switch and upstream of the power electronic switch.

[0010] In one example, in the open state of the solid-state circuit breaker, the disconnecting switch is open and the power electronic switch is open; and in the standby state of the solid-state circuit breaker, the disconnecting switch is closed and the power electronic switch is open.

[0011] In one example, the solid-state circuit breaker disables the power electronic switch by not closing it.

[0012] In one example, the downstream-to-ground resistor is an equivalent downstream-to-ground resistor downstream of the power electronic switch.

[0013] In one example, in the open state of the solid-state circuit breaker, the power electronic switch is open, and in the standby state of the solid-state circuit breaker, the disconnecting switch is closed, and the power electronic switch is closed.

[0014] In one example, the solid-state circuit breaker disables the power electronic switch by disconnecting it.

[0015] In one example, the solid-state circuit breaker further includes a detector configured to detect the input voltage of the power supply, a first voltage to ground and a second voltage to ground, and / or an equivalent downstream resistance to ground, and send the information to a controller.

[0016] In one example, the downstream-to-ground resistor is connected downstream of the disconnect switch and between the positive terminal of the power supply and ground.

[0017] In one example, the upstream insulation impedance includes the positive terminal insulation impedance of the power source to ground and the negative terminal insulation impedance of the power source to ground.

[0018] According to the embodiments of this utility model, by utilizing the inherent isolating switch of the solid-state circuit breaker and the inherent equivalent resistance value in the circuit, and by adding only one power line to the PE sampling circuit, upstream insulation impedance anomalies can be identified in advance, which is low-cost and can avoid safety hazards. Attached Figure Description

[0019] The above and other aspects, features, and advantages of specific embodiments of the present invention will become clearer from the following description taken in conjunction with the accompanying drawings, in which:

[0020] Figure 1 This is a diagram illustrating a schematic structure of a solid-state circuit breaker according to an embodiment of the present invention;

[0021] Figure 2 A schematic diagram of a solid-state circuit breaker in the open state according to an embodiment of the present invention is shown;

[0022] Figure 3A schematic diagram of a solid-state circuit breaker in standby mode according to an embodiment of the present invention is shown.

[0023] Figure 4 This is a schematic diagram showing a solid-state circuit breaker according to another embodiment of the present invention;

[0024] Figure 5 A schematic diagram of a solid-state circuit breaker in the open state according to another embodiment of the present invention is shown; and

[0025] Figure 6 A schematic diagram of a solid-state circuit breaker in standby mode according to another embodiment of the present invention is shown. Detailed Implementation

[0026] Before proceeding with the detailed description below, it may be advantageous to define certain words and phrases used throughout this invention. The terms “comprising” and “including” and their derivatives mean, but are not limited to, any of the following. The term “controller” or “control unit” means any device, system, or part thereof that controls at least one operation. Such a controller may be implemented in hardware, or a combination of hardware and software and / or firmware. For example, a controller may include, for instance, an application-specific integrated circuit (ASIC), a general-purpose or special-purpose central processing unit (CPU), a digital signal processor (DSP), and programmable logic devices such as a field-programmable gate array (FPGA). A controller may be manufactured as a single printed circuit board (PCB) or distributed across several interconnected PCBs. A controller may include other processing circuitry; for example, a controller may include two processing circuits such as an FPGA and a CPU interconnected on a PCB. The functionality associated with any particular controller may be centralized or distributed, either local or remote. The phrase “at least one,” when used with a list of items, means that different combinations of one or more of the listed items may be used, and perhaps only one item from the list is required. For example, "at least one of A, B, and C" includes any one of the following combinations: A, B, C, A and B, A and C, B and C, A and B and C. Furthermore, in the description of this utility model, the terms "first," "second," etc., are used only for distinguishing descriptions and should not be construed as indicating or implying relative importance or order. In embodiments of this disclosure, unless otherwise expressly stated, "connection" does not necessarily mean "direct connection" or "direct contact," but only requires electrical connection.

[0027] Definitions of other specific words and phrases are provided throughout this invention. Those skilled in the art will understand that, in many, if not most, cases, such definitions apply to the prior and future use of the words and phrases thus defined.

[0028] The various embodiments of the present invention described below with reference to the accompanying drawings are for illustrative purposes only and should not be construed as limiting the scope of the present invention in any way. Those skilled in the art will understand that the principles of the present invention can be implemented in any suitably arranged system or device. In some cases, the actions described in the present invention can be performed in different orders and still achieve the desired result. Furthermore, the processes depicted in the drawings do not necessarily require the specific order or sequential sequence shown to achieve the desired result. In certain embodiments, multitasking and parallel processing may be advantageous.

[0029] The text and accompanying drawings are provided by way of example only to aid in understanding the present invention. They should not be construed as limiting the scope of the appended claims in any way. Although certain embodiments and examples have been provided, it will be clear to those skilled in the art, based on the content of the present invention, that changes can be made to the illustrated embodiments and examples without departing from the scope of the present invention.

[0030] Currently, there are three commonly used methods for testing insulation impedance.

[0031] The first method is the signal injection method. This method injects a detection signal of a specific frequency (usually a low-frequency AC signal) and amplitude into the DC system, and then calculates the insulation resistance by detecting the current and voltage response of this signal in the system. However, this method requires an additional signal injection device, increasing the complexity and cost of the system; the injected signal may also interfere with other sensitive devices in the system.

[0032] The second method is capacitive reactance measurement. This method utilizes the capacitive reactance characteristic of the insulating medium in a DC system under AC signals. When the DC system is well-insulated, the capacitance and capacitive reactance of the positive and negative terminals to ground are relatively stable. The change in insulation impedance is determined by measuring the change in the capacitive reactance of the positive and negative terminals to ground. However, the measurement results are easily interfered with by other capacitive components in the system (such as the distributed capacitance of cables, the filter capacitance of equipment, etc.), requiring precise measuring instruments and a complex calibration process to ensure measurement accuracy.

[0033] The third method is leakage current detection. This method directly detects the leakage current between the positive and negative terminals of the DC system and ground. By installing a high-precision leakage current sensor, leakage current will be generated when the insulation resistance decreases. The sensor detects the change in the magnitude of the leakage current, thereby inferring the insulation impedance. However, this method can only indirectly reflect the insulation impedance and cannot accurately measure the value of the insulation impedance; moreover, when there are multiple leakage current sources or interference currents in the system, it may lead to misjudgment.

[0034] Figure 1 This is a diagram illustrating a schematic structure of a solid-state circuit breaker 100 according to an embodiment of the present invention.

[0035] like Figure 1 As shown, the solid-state circuit breaker 100 may include a disconnecting switch S, power electronic switches Q1 and Q2, and a controller (not shown).

[0036] In addition, solid-state circuit breakers also include: input terminals, which are connected to the positive and negative terminals of the power supply.

[0037] The disconnector switch S can be connected in series in the main circuit and can be connected to a power source; for example, the first terminal of the disconnector switch S can be connected to the positive terminal (P) of the power source. Power electronic switches Q1 and Q2 are also connected in series in the main circuit and can be connected in series with the disconnector switch; for example, the first terminal of the power electronic switches Q1 and Q2 can be connected to the second terminal of the disconnector switch S. The controller can be configured to receive the input voltage of the power source, the voltage to ground of the positive terminal of the power source, and the downstream resistance to ground value of the downstream resistor R1, and control whether to disable the power electronic switches.

[0038] According to the embodiments of this utility model, by utilizing the inherent isolating switch S of the solid-state circuit breaker and the inherent equivalent resistance value in the circuit, and by adding only one power line (P and N) to the PE sampling circuit, upstream insulation impedance anomalies can be identified in advance and the power electronic switch can be controlled to be disabled. This method is low-cost and can avoid safety hazards.

[0039] Although Figure 1 One end of the downstream-to-ground resistor R1 is shown as being between the disconnecting switch S and the power electronic switch Q1Q2, that is, as an equivalent downstream-to-ground resistor downstream of the disconnecting switch S and upstream of the power electronic switch Q1Q2. However, the embodiments of this utility model are not limited thereto.

[0040] In another example, the downstream resistor to ground R1 can also be downstream of the power electronic switch Q1Q2, that is, the equivalent downstream resistor to ground downstream of the power electronic switch Q1Q2.

[0041] Furthermore, in another example, the solid-state circuit breaker 100 may additionally include a separate downstream-to-ground resistor R1. Similarly, in the case of including a separate downstream-to-ground resistor R1, although in Figure 1 The diagram shows one end of the downstream ground resistor R1 configured to connect between the disconnecting switch S and the power electronic switch Q1Q2; however, the embodiments of this invention are not limited thereto. One end of the downstream ground resistor R1 can also be connected downstream of the power electronic switch Q1Q2, i.e., the second terminal of the power electronic switch Q1Q2, and the other end of the downstream ground resistor R1 can be connected to PE.

[0042] Furthermore, an inductor L can be connected in series between the second terminal of the disconnecting switch S and the first terminal of the power electronic switch Q1Q2. However, the embodiments of this utility model are not limited thereto.

[0043] Therefore, as another example, one end of the downstream ground resistor R1 can be connected between the disconnecting switch S and the inductor L (e.g., Figure 1 (as shown), or between the inductor L and the first terminal of the power electronic switch Q1Q2 (not shown).

[0044] Therefore, according to the embodiments of this utility model, by utilizing the inherent disconnecting switch S of the solid-state circuit breaker and adding only a ground resistor R1 and one power line (P and N) to the PE sampling circuit, upstream insulation impedance anomalies can be identified in advance, which is low-cost and can avoid safety hazards.

[0045] Hereinafter, embodiments of the present invention will be described using MOSFETs as examples of solid-state circuit breakers. However, those skilled in the art will recognize that the present invention is not limited thereto, and any other suitable device may be used as a solid-state circuit breaker.

[0046] Hereinafter, the embodiments of this utility model will be described with the example that the downstream resistor to ground R1 is an equivalent downstream resistor to ground. The case where the downstream resistor to ground R1 is a separately connected element is similar to the case where it is an equivalent downstream resistor to ground, and will not be described again here.

[0047] like Figure 1 As shown, the input voltage of the power supply can be represented as Vin, the voltage of the positive terminal of the power supply to ground can be represented as Vpe, the downstream resistance value of the downstream resistor to ground R1 can be represented as R1, and the upstream insulation impedance includes the insulation impedance of the positive terminal of the power supply to ground Rp and the insulation impedance of the negative terminal of the power supply to ground Rn.

[0048] In one example, the insulation resistances Rp and Rn can represent the equivalent insulation resistances of the positive and negative power supply lines of the DC input to ground (PE), respectively.

[0049] According to an embodiment of this utility model, the resistance value R1 of the downstream resistor to ground is known or can be obtained by measurement. The input voltage Vin and the voltage to ground of the positive terminal of the power supply Vpe can also be obtained by measurement. Therefore, by using the resistance value R1, the input voltage Vin, and Vpe measured under different states of the solid-state circuit breaker, the insulation impedances Rp and Rn can be calculated using the voltage divider relationship. By comparing the calculated Rp and Rn with threshold values, it can be determined whether the upstream insulation impedance is abnormal.

[0050] In one example, a solid-state circuit breaker can have an open state and a standby state. Therefore, the voltage to ground Vpe of the positive terminal of the power supply can include: a first voltage to ground Vpe1 in the open state of the solid-state circuit breaker and a second voltage to ground Vpe2 in the standby state of the solid-state circuit breaker.

[0051] In one example, the controller of a solid-state circuit breaker can calculate the upstream insulation impedances Rp and Rn based on the input voltage Vin of the power supply, the first voltage to ground Vpe1, the second voltage to ground Vpe2, and the resistance value R1 of the downstream resistor to ground, and determine that the upstream insulation impedance is abnormal when the upstream insulation impedances Rp and Rn are below a threshold.

[0052] In one example, a solid-state circuit breaker can disable the power electronic switch by not closing it, i.e., keeping the power electronic switch in an open state to prevent fault propagation downstream. Additionally, the isolating switch S can also be disconnected.

[0053] In one example, a solid-state circuit breaker can disable the power electronic switch by disconnecting it to prevent the fault from propagating downstream. Additionally, the isolating switch S can also be disconnected.

[0054] In one example, the solid-state circuit breaker may further include: a detector (not shown) configured to detect the input voltage Vin of the power supply and the voltage Vpe of the positive terminal of the power supply to ground, namely a first voltage Vpe1 and a second voltage Vpe2, and send them to the controller.

[0055] In addition, in one example, the detector can also detect the downstream-to-ground resistance value R1 of the downstream-to-ground resistor and send it to the controller.

[0056] Further reference will be made thereafter. Figures 2 to 6 This invention provides a detailed description of a DC solid-state circuit breaker capable of performing insulation detection according to an embodiment of the present invention.

[0057] Figure 2 A schematic diagram of a solid-state circuit breaker 100 in the open state according to an embodiment of the present invention is shown.

[0058] like Figure 2 As shown, when the solid-state circuit breaker 100 is in the open state, the isolating switch S is open, and the power electronic switches Q1 and Q2 are also open. At this time, the first voltage to ground Vpe1 is measured, and the following equation 1 can be obtained.

[0059]

[0060] Figure 3 A schematic diagram of a solid-state circuit breaker 100 in standby mode according to an embodiment of the present invention is shown.

[0061] like Figure 3 As shown, when the solid-state circuit breaker 100 is in standby mode, the disconnecting switch S is closed and the power electronic switches Q1 and Q2 are open. At this time, the second voltage to ground Vpe2 is measured, and the following equation 2 can be obtained.

[0062]

[0063] Since R1, Vin, Vpe1, and Vpe2 are known, the upstream insulation resistances Rp and Rn can be obtained by combining Equations 1 and 2, as shown in Equations 3 and 4 below.

[0064]

[0065] The thresholds for Rp and Rn can be set according to the system configuration. If, after each power-on, the detected / calculated Rp or Rn value is lower than the preset threshold after closing the isolating switch S, it can be determined that the upstream insulation impedance is abnormal.

[0066] When an abnormality in upstream insulation resistance is detected, an alarm can be reported, and the power electronic switch can be disabled. This prevents the fault from propagating further down to the next level by keeping the power electronic switch open.

[0067] exist Figure 3 In the scenario shown, the solid-state circuit breaker can disable the power electronic switch by not closing it, i.e., keeping the power electronic switch in an open state to prevent the fault from propagating downstream. Furthermore, the disconnector switch S can also be disconnected.

[0068] It should be noted that the relationships shown in Equations 1 to 4 are only simplified calculations. However, those skilled in the art should understand that downstream of the disconnector S, there are also voltages between each pair of the P-line, N-line, and ground (PE) of the power supply. Therefore, in practical applications, the voltages and / or equivalent impedances between each pair of the P-line, N-line, and PE-line downstream of the disconnector S can be considered simultaneously, and the upstream insulation impedances Rp and Rn can be calculated based on voltage division relationships similar to those in Equations 1 to 4.

[0069] Figure 4 This is a schematic diagram showing a solid-state circuit breaker 400 according to another embodiment of the present invention.

[0070] Figure 4 Solid-state circuit breaker 400 and Figure 1 The difference in the solid-state circuit breaker 100 is that the downstream-to-ground resistor R1 is downstream of the power electronic switch Q1Q2, that is, the downstream-to-ground resistor R1 is the equivalent downstream-to-ground resistor downstream of the power electronic switch Q1Q2.

[0071] Furthermore, in the case where the solid-state circuit breaker 100 additionally includes a separate downstream-to-ground resistor R1, one end of the downstream-to-ground resistor R1 is connected to the second terminal of the power electronic switch Q1Q2, and the other end of the downstream-to-ground resistor R1 is connected to PE.

[0072] References Figures 1 to 3 Similarly, the description of the solid-state circuit breaker 100 is as follows: Figure 4 In this embodiment of the invention, the downstream resistance to ground of the downstream resistor R1 is known, and the input voltage Vin and the voltage to ground of the positive terminal of the power supply Vpe can be obtained by measurement. Therefore, by using the resistance value R1, the input voltage Vin, and Vpe measured under different states of the solid-state circuit breaker, the insulation impedances Rp and Rn can be calculated. By comparing the calculated Rp and Rn with threshold values, it can be determined whether the upstream insulation impedance is abnormal.

[0073] Figure 5 A schematic diagram of a solid-state circuit breaker 400 in the open state according to another embodiment of the present invention is shown.

[0074] like Figure 5 As shown, when the solid-state circuit breaker 400 is in the open state, the power electronic switches Q1 and Q2 are open. At this time, as shown in the reference... Figure 2 Similarly, the first voltage to ground, Vpe1, is measured, and Equation 1 can be obtained.

[0075] At this time, the isolating switch S can be either open or closed.

[0076] Figure 6 A schematic diagram of a solid-state circuit breaker 400 in standby mode according to another embodiment of the present invention is shown.

[0077] like Figure 6 As shown, when the solid-state circuit breaker 400 is in standby mode, the disconnecting switch S is closed, and the power electronic switches Q1 and Q2 are also closed. At this time, the second voltage to ground Vpe2 is measured, and Equation 2 can be obtained.

[0078] Since R1, Vin, Vpe1, and Vpe2 are known, the upstream insulation resistances Rp and Rn can be obtained by combining Equations 1 and 2, as shown in Equations 3 and 4 above.

[0079] Similarly, in practical applications, the voltage and / or equivalent impedance between each pair of the P-line, N-line, and PE-line downstream of the disconnecting switch S and the power electronic switch Q1Q2 can be considered simultaneously, and the upstream insulation impedances Rp and Rn can be calculated based on voltage division relationships similar to those in Equations 1 to 4.

[0080] Similarly, the thresholds for Rp and Rn can be set according to the system configuration. If, after each power-on, the detected / calculated Rp or Rn value is lower than the preset threshold after closing the isolating switch S, it can be determined that the upstream insulation impedance is abnormal.

[0081] When an abnormality in upstream insulation resistance is detected, an alarm can be reported, and the power electronic switch can be disabled. This prevents the fault from propagating further down to the next level by keeping the power electronic switch open.

[0082] exist Figure 6 In the scenario shown, the solid-state circuit breaker can disable the power electronic switch by disconnecting it to prevent the fault from propagating downstream. Additionally, the disconnector S can also be disconnected.

[0083] Therefore, the insulation detection scheme for the DC solid-state circuit breaker according to this embodiment of the invention utilizes the inherent disconnecting switch of the DC solid-state circuit breaker to identify upstream insulation impedance anomalies in advance during standby mode, thus avoiding safety hazards. Furthermore, the insulation detection scheme for the DC solid-state circuit breaker according to this embodiment of the invention relies on the inherent disconnecting switch of a conventional solid-state circuit breaker, adding only a downstream ground resistor and a power line-PE sampling circuit, resulting in low cost.

[0084] Although the present invention has been described with reference to exemplary embodiments, various changes and modifications may be suggested to those skilled in the art. The present invention is intended to cover such changes and modifications that fall within the scope of the appended claims.

[0085] Any description in this invention should not be construed as implying that any particular element, step, or function is an essential element that must be included within the scope of the claims. The scope of the patent subject matter is defined only by the claims.

Claims

1. A solid-state circuit breaker, characterized in that, include: The input terminal is connected to the positive and negative terminals of the power supply. The disconnecting switch is connected in series in the main circuit and connected to the positive terminal of the power supply; The power electronic switch is connected in series in the main circuit and in series with the disconnecting switch; as well as The controller is configured to receive the input voltage of the power supply, the voltage to ground of the positive terminal of the power supply, and the downstream resistance to ground value of the downstream resistor to ground, and to control whether to disable the power electronic switch.

2. The solid-state circuit breaker according to claim 1, characterized in that, The voltage to ground of the positive terminal of the power supply includes: a first voltage to ground in the open state of the solid-state circuit breaker and a second voltage to ground in the standby state of the solid-state circuit breaker.

3. The solid-state circuit breaker according to claim 2, characterized in that, The controller is also configured to: Based on the voltage division relationship between the power supply input voltage, the first voltage to ground, the second voltage to ground, and the downstream resistance to ground, the upstream insulation impedance is determined; and When the upstream insulation impedance is lower than the threshold, the upstream insulation impedance is determined to be abnormal.

4. The solid-state circuit breaker according to claim 3, characterized in that, The controller is also configured to disable the power electronic switch when an abnormal upstream insulation impedance is detected.

5. The solid-state circuit breaker according to claim 2, characterized in that, The downstream-to-ground resistor is an equivalent downstream-to-ground resistor downstream of the disconnecting switch and upstream of the power electronic switch.

6. The solid-state circuit breaker according to claim 5, characterized in that, In the open state of the solid-state circuit breaker, the disconnecting switch is open, and the power electronic switch is open, and In the standby state of the solid-state circuit breaker, the disconnecting switch is closed and the power electronic switch is open.

7. The solid-state circuit breaker according to claim 6, characterized in that, The solid-state circuit breaker disables the power electronic switch by not closing it.

8. The solid-state circuit breaker according to claim 2, characterized in that, The downstream-to-ground resistor is an equivalent downstream-to-ground resistor downstream of the power electronic switch.

9. The solid-state circuit breaker according to claim 8, characterized in that, In the open state of the solid-state circuit breaker, the power electronic switch is open, and In the standby state of the solid-state circuit breaker, the disconnecting switch is closed, and the power electronic switch is closed.

10. The solid-state circuit breaker according to claim 9, characterized in that, The solid-state circuit breaker disables the power electronic switch by disconnecting it.

11. The solid-state circuit breaker according to claim 2, characterized in that, Also includes: The detector is configured to detect the input voltage of the power supply, the first voltage to ground and the second voltage to ground, and / or the downstream resistance to ground value, and send them to the controller.

12. The solid-state circuit breaker according to claim 1, characterized in that, The downstream ground resistor is connected downstream of the disconnect switch and between the positive terminal of the power supply and ground.

13. The solid-state circuit breaker according to claim 3, characterized in that, The upstream insulation impedance includes the positive terminal insulation impedance of the power supply to ground and the negative terminal insulation impedance of the power supply to ground.

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