Aircraft power system line insulation detection circuit and method

Abstract

The application provides an aircraft power supply system line insulation detection circuit and a detection method. The aircraft power supply system line insulation detection circuit comprises at least one semiconductor electronic switch, a direct-current test power supply and a current detector. Any semiconductor electronic switch is located at a positive electrode end of a power supply circuit or a load device circuit. A negative electrode of the direct-current test power supply is connected with a pyrotechnic test interface of a pyrotechnic ignition circuit output negative end. A positive electrode of the direct-current test power supply is connected with a shell. The current detector is located between the direct-current test power supply and the pyrotechnic test interface of the pyrotechnic ignition circuit output negative end or between the direct-current test power supply and the shell. The technical scheme of the application can solve the technical problem that the aircraft power supply system device circuit needs to be disconnected when the aircraft power supply system line insulation is detected in the prior art.

Description

Technical Field

[0001] This invention relates to the field of aircraft electrical technology, and in particular to an insulation detection circuit and method for aircraft power system circuits. Background Technology

[0002] The power lines of aircraft electrical systems typically employ a two-wire design, meaning the power return line is not routed through the aircraft casing. This design prevents direct electrical connection between the power lines and the equipment or aircraft casing. The equipment and aircraft casings are electrically connected to form an equipotential body as close to ideal as possible. This serves two purposes: firstly, it allows the casing to act as a shield for the internal electrical system wiring, helping to eliminate the effects of external radiated interference; secondly, it utilizes the casing's equipotential body as a common site for dissipating interference signals, which is beneficial for electromagnetic compatibility between devices. If the insulation between the equipment power lines and the casing deteriorates or a direct electrical connection exists, it not only increases the risk of short circuits and reduces the reliability of the electrical system, but also makes it easier for interference signals present in the casing to be introduced. Therefore, testing the insulation performance of the aircraft power lines to the casing is a crucial step in confirming the condition of the aircraft power lines.

[0003] The common method for testing the insulation performance between the power supply line and the housing is to use an insulation meter to measure the insulation resistance between the circuit checkpoint and the housing. By applying a test voltage between the circuit checkpoint and the housing, the measured current under the applied test voltage corresponds to the circuit resistance, thus determining the insulation status of the line to the housing. Conventional methods in the prior art generally disconnect the power supply equipment from the circuit. The circuit checkpoint is easily accessible from the disconnected line end, allowing the insulation measuring instrument to be connected for measurement. However, implementing this conventional method requires disconnecting the relevant equipment. This is not feasible when the aircraft's electrical equipment is fully assembled. Even if the above test can be performed during final assembly before the relevant circuits of the equipment are connected, the opportunity to check the insulation resistance is still lost later. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art.

[0005] According to one aspect of the present invention, an insulation detection circuit for an aircraft power system is provided. The aircraft power system insulation detection circuit includes: at least one semiconductor electronic switch, a DC test power supply, and a current detector. Any semiconductor electronic switch is located at the positive terminal of the power supply circuit or the load device circuit. The negative terminal of the DC test power supply is connected to the pyrotechnic test interface at the negative output terminal of the pyrotechnic ignition circuit. The positive terminal of the DC test power supply is connected to the housing. The current detector is located between the DC test power supply and the pyrotechnic test interface at the negative output terminal of the pyrotechnic ignition circuit or between the DC test power supply and the housing.

[0006] Furthermore, semiconductor-type electronic switches employ MOSFET switching transistors.

[0007] Furthermore, the casing can be an equipment casing or an aircraft casing.

[0008] According to another aspect of the present invention, an aircraft power system is provided, the aircraft power system comprising: a bus power supply, multiple power circuits, multiple load device circuits, a pyrotechnic ignition circuit, and a pyrotechnic and line insulation detection circuit, wherein any power circuit, any load device circuit and the pyrotechnic ignition circuit are powered by the bus power supply, the pyrotechnic is ignited under the control of the pyrotechnic ignition circuit, and the line insulation detection circuit adopts the aircraft power system line insulation detection circuit as described above.

[0009] Furthermore, the ignition circuit for pyrotechnic devices includes an ignition relay switch for pyrotechnic devices, which is connected to the positive line of the bus power supply, and the pyrotechnic device is connected to the negative line of the bus power supply.

[0010] Furthermore, the ignition circuit for the pyrotechnic device includes a first semiconductor-type electronic switch for the pyrotechnic device and a second semiconductor-type electronic switch for the pyrotechnic device. The first semiconductor-type electronic switch for the pyrotechnic device is connected to the positive line of the bus power supply, and the second semiconductor-type electronic switch for the pyrotechnic device is connected to the negative line of the bus power supply and the pyrotechnic device, respectively.

[0011] Furthermore, the voltage of the DC test power supply in the line insulation detection circuit does not exceed the short-time maximum voltage that the aircraft power system can withstand.

[0012] Furthermore, at least one load device circuit has a bridging resistor between the positive and negative power supply ports.

[0013] According to another aspect of the present invention, a method for detecting the insulation of a power system circuit in an aircraft is provided, wherein the method employs the aircraft power system circuit insulation detection circuit described above for detecting the insulation of the circuit.

[0014] Furthermore, the method for detecting the insulation of the aircraft power system circuit includes: after the delay control period ends, performing circuit insulation detection using the aircraft power system circuit insulation detection circuit described above.

[0015] This invention provides a circuit and method for detecting insulation in an aircraft power system circuit. The circuit utilizes a semiconductor electronic switch at the positive terminal of at least one power circuit or load device circuit, and connects an insulation test power supply to the pyrotechnic test interface at the negative output terminal of the pyrotechnic ignition circuit. Without disconnecting the aircraft power system circuit (i.e., without changing the circuit state), and without adding additional circuitry, the circuit detects the insulation status between the power line and the casing simultaneously by designing the pyrotechnic ignition control detection function interface and determining the timing of pyrotechnic circuit detection. Compared to existing technologies, this invention solves the problem of needing to disconnect the aircraft power system circuit during insulation testing. Attached Figure Description

[0016] The accompanying drawings, which form part of this specification, are provided to further illustrate embodiments of the invention and, together with the textual description, explain the principles of the invention. It is obvious that the drawings described below are merely some embodiments of the invention, and those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0017] Figure 1 A schematic diagram of an aircraft power system according to a specific embodiment of the present invention is shown;

[0018] Figure 2 A schematic diagram of an aircraft power system according to another specific embodiment of the present invention is shown;

[0019] Figure 3 A schematic diagram of an aircraft power system in the prior art is shown. Detailed Implementation

[0020] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0022] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0023] like Figure 1 As shown, according to a specific embodiment of the present invention, an insulation detection circuit for an aircraft power system is provided. The insulation detection circuit for an aircraft power system includes: at least one semiconductor electronic switch, a DC test power supply, and a current detector. Any semiconductor electronic switch is located at the positive terminal of the power supply circuit or the load device circuit. The negative terminal of the DC test power supply is connected to the pyrotechnic test interface at the negative output terminal of the pyrotechnic ignition circuit. The positive terminal of the DC test power supply is connected to the housing. The current detector is located between the DC test power supply and the pyrotechnic test interface at the negative output terminal of the pyrotechnic ignition circuit or between the DC test power supply and the housing.

[0024] This configuration provides an insulation detection circuit for an aircraft power system. This circuit utilizes a semiconductor electronic switch at the positive terminal of at least one power circuit or load device circuit, and connects an insulation test power supply to the pyrotechnic test interface at the negative output terminal of the pyrotechnic ignition circuit. Without disconnecting the aircraft power system equipment circuit (i.e., without changing the power system circuit state), and without adding additional circuitry, it detects the insulation status between the power line and the casing simultaneously by utilizing the design of the pyrotechnic ignition control detection function interface and the timing of pyrotechnic circuit detection. Compared to existing technologies, this invention solves the technical problem of needing to disconnect the aircraft power system equipment circuit when performing insulation detection.

[0025] Furthermore, in this invention, the semiconductor electronic switch can be a MOSFET switch. In this invention, if a parasitic diode exists within the semiconductor electronic switch such as the MOSFET switch, the circuit exhibits unidirectional conduction characteristics when the gate is not driven. This invention utilizes this characteristic to achieve insulation detection, using the parasitic diode in the MOSFET switch within the DC power supply system equipment to form a detection circuit without adding any additional circuit components.

[0026] Furthermore, in this invention, the housing can be configured as an equipment housing or an aircraft housing, depending on the actual testing requirements.

[0027] According to another aspect of the present invention, an aircraft power system is provided, the aircraft power system comprising: a bus power supply, multiple power circuits, multiple load device circuits, a pyrotechnic ignition circuit, and a pyrotechnic and line insulation detection circuit, wherein any power circuit, any load device circuit and the pyrotechnic ignition circuit are powered by the bus power supply, the pyrotechnic is ignited by the pyrotechnic ignition circuit, and the line insulation detection circuit adopts the aircraft power system line insulation detection circuit as described above.

[0028] This configuration provides an aircraft power system that, by configuring the aircraft power system circuit insulation detection circuit as described above, can detect the insulation status between the power line and the casing simultaneously with the insulation wire detection of the ignition circuit of the pyrotechnics, without adding additional circuits, and without disconnecting the circuit of the aircraft power system equipment.

[0029] like Figure 3 As shown, a prior art aircraft power system is presented, in Figure 3 In this diagram, bus + and bus - represent the positive and negative lines of the bus power supply, respectively. The bus power supply is the common power distribution terminal for all electrical equipment on the aircraft. Multiple power sources can exist in the system, for example... Figure 3 Power supplies 1 and 2 are shown. Multiple load devices may exist in the system circuit, for example... Figure 3 The load devices shown are 0, 1, and 2. The number of power supplies and load devices listed above is merely an example and is not limited to this. Switches control the circuit connection between the power supply and bus +, and between the load devices and bus +. Power supply on / off control of the devices is achieved by controlling the on / off connection of the circuit between the bus power supply and the devices. Traditionally, relays or contactors are used as switching devices to achieve power supply control. Generally, the switch control device is designed on one end of the power supply, while no control is set on the other end. Typically, the switch is located at the positive terminal of the power supply, while the negative terminal (i.e., the power return terminal) is directly connected in parallel to the bus power return terminal, such as... Figure 3 Switches K0-K4. Figure 3 The two test interfaces directly lead out to the busbar + and busbar - respectively. During insulation testing, two test devices apply DC test voltages respectively. If there is a short circuit to the casing or a drop in insulation in the line connected to busbar + or busbar -, this method can be used to check. The switching devices K0-K4 mentioned above are relay-type products, which need to be tested at both ends of busbar + and busbar - to achieve insulation test coverage of the power supply line. That is, the existing technology requires the design of dedicated test interfaces, such as directly leading out the positive and negative lines of the busbar power supply, to realize the insulation detection of the line.

[0030] The aircraft power system employing the present invention, such as Figure 1 As shown, by utilizing the opportunity of performing insulation testing between the pyrotechnic ignition circuit and the housing at the pyrotechnic test interface, the insulation testing circuit measures the insulation resistance between the negative output terminal of the pyrotechnic ignition circuit and the housing at the pyrotechnic test interface, which is equivalent to measuring the insulation resistance between the negative line of the bus power supply and the housing. Since the circuit's on / off control is achieved using semiconductor electronic switching devices such as MOSFETs, and parasitic diodes exist in these devices, a loop condition is established. Regardless of the voltage polarity between the pyrotechnic test interface and the housing, any decrease in insulation to the housing on any connection line of the positive or negative bus power supply in the aircraft power system will result in an increase in the test current. That is, in this invention, there is no need to design a dedicated test interface; insulation testing of the entire system's power circuit can be achieved simply by using the pyrotechnic test interface during pyrotechnic testing. Simultaneously, by utilizing the characteristics of the body diode in the electronic switching devices and changing the polarity of the applied test voltage between the circuit check point and the housing, this invention can be adapted to power system circuits controlled by electronic switching circuits. By selecting appropriate test voltage access points for different power supply control circuit schemes of the power system, the line insulation detection of this invention can be applied to most circuits except for circuits of physically isolated devices such as relays that sample both positive and negative poles, thus having a certain degree of versatility.

[0031] like Figure 1 As shown in the figure, in a specific embodiment of the present invention, the pyrotechnic ignition circuit includes a pyrotechnic ignition relay switch, which is connected to the positive line of the bus power supply, and the pyrotechnic is connected to the negative line of the bus power supply.

[0032] like Figure 2 As shown, in another specific embodiment of the present invention, the pyrotechnic ignition circuit includes a first pyrotechnic semiconductor electronic switch and a second pyrotechnic semiconductor electronic switch. The first pyrotechnic semiconductor electronic switch is connected to the positive line of the bus power supply, and the second pyrotechnic semiconductor electronic switch is connected to both the negative line of the bus power supply and the pyrotechnic device. In this invention, if the pyrotechnic ignition circuit adopts a dual-control method with positive and negative lines to achieve pyrotechnic ignition control during system application, the pyrotechnic ignition can be controlled by the first and second pyrotechnic semiconductor electronic switches.

[0033] Furthermore, in this invention, the voltage of the DC test power supply in the line insulation detection circuit does not exceed the short-time maximum voltage that the aircraft power system can withstand. Based on the rated operating voltage specifications of the power system under test, the detection voltage that can be applied to the power port circuit is set, generally not exceeding the short-time maximum voltage that the power system can withstand. As a specific embodiment of this invention, the rated voltage of the power system's bus power supply is a DC 28V power supply, and correspondingly, a DC 50V voltage can be used to perform insulation detection on the system circuit. Selecting a reasonable test voltage ensures the safety of the test and enables rapid detection of the overall insulation performance of the system.

[0034] Furthermore, in this invention, at least one load device circuit has a bridging resistor between its positive and negative power supply ports. This bridging resistor is located within the equipment controlling the aircraft bus power supply and is primarily used for sampling the equipment bus power supply signal.

[0035] Based on general measurement methods, the aircraft power system of this invention utilizes the single-phase conduction characteristics of the parasitic diode in the MOSFET switch and the circuit conditions of the bridging detection resistor between the two poles of the load device power supply to simultaneously perform insulation testing of the ignition circuit of pyrotechnic devices and determine the insulation performance of the entire system power network to the shell.

[0036] According to another aspect of the present invention, a method for detecting the insulation of a power system circuit in an aircraft is provided, wherein the method employs the aircraft power system circuit insulation detection circuit described above for detecting the insulation of the circuit.

[0037] By employing this configuration, the aircraft power system circuit insulation testing method can detect the insulation status between the power lines and the casing simultaneously with the insulation testing of the pyrotechnic ignition circuit, without interrupting the power system equipment circuits or adding additional circuits. When the insulation performance of any device power circuit connected to the bus power supply deteriorates to the casing, an abnormal detection current can be measured at the testing equipment, thereby determining the insulation status of the entire power system to the casing. This aircraft power system circuit insulation testing method is simple to operate and easily automated.

[0038] Furthermore, in this invention, the method for detecting the insulation of the aircraft power system circuit includes: after the delay control period ends, performing circuit insulation detection using the aircraft power system circuit insulation detection circuit described above.

[0039] Considering that filter circuits are often installed at the ports in the system circuit, and that capacitance exists between the positive and negative terminals of the power supply or between the positive and negative terminals and the casing, a delay control period needs to be set when performing line insulation testing with power on. During this delay control period, the line insulation test results are not read to avoid the influence of capacitor charging on the test results. After the delay control period ends, the line insulation test data is read, and the circuit status is judged based on the data results to determine whether it meets the requirements. The length of the delay control period depends on the capacitance between the positive and negative lines of the bus power supply. Therefore, the delay time can be adjusted according to the circuit conditions during the initial tests of the system to ultimately determine a relatively fixed delay control duration. This delay control period can serve as an indicator of the consistency status of the system circuit. If the capacitance value in the power system circuit changes significantly, the measured sampling current representing the insulation resistance will also change significantly within the determined delay control period. This can indirectly indicate whether the power system circuit has experienced changes in its circuit parameter characteristics.

[0040] This invention avoids the influence of capacitor charging on insulation detection during the initial power-on phase by setting a power-on delay. Furthermore, through preliminary debugging, the delay control period can be used as a parameter for determining the consistency of the power system circuit state.

[0041] In a specific embodiment of the present invention, the insulation detection method for aircraft power system circuits of the present invention can be used to identify insulation problems at the power supply terminals of products such as controllers, guidance systems, and fuel pumps during the final assembly stage.

[0042] In summary, this invention provides an insulation detection circuit and method for aircraft power system circuits. This circuit utilizes a semiconductor electronic switch at the positive terminal of at least one power circuit or load device circuit, and connects an insulation test power supply to the pyrotechnic test interface at the negative output terminal of the pyrotechnic ignition circuit. Without disconnecting the aircraft power system equipment circuit (i.e., without changing the power system circuit state), and without adding additional circuitry, it employs the design of the pyrotechnic ignition control detection function interface and the timing of pyrotechnic circuit detection to simultaneously detect the insulation of the pyrotechnic ignition circuit and the insulation state between the power line and the casing. Compared to existing technologies, this invention solves the technical problem of needing to disconnect the aircraft power system equipment circuit during insulation detection.

[0043] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0044] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An insulation detection circuit for an aircraft power system, characterized in that, The aircraft power system circuit insulation detection circuit includes: at least one semiconductor electronic switch, a DC test power supply, and a current detector. Any semiconductor electronic switch is located at the positive terminal of the power supply circuit or the load device circuit. The negative terminal of the DC test power supply is connected to the pyrotechnic test interface at the negative output terminal of the pyrotechnic ignition circuit. The positive terminal of the DC test power supply is connected to the housing. The current detector is located between the DC test power supply and the pyrotechnic test interface at the negative output terminal of the pyrotechnic ignition circuit, or between the DC test power supply and the housing.

2. The aircraft power system circuit insulation detection circuit according to claim 1, characterized in that, The semiconductor electronic switch uses a MOSFET switching transistor.

3. The aircraft power system circuit insulation detection circuit according to claim 1, characterized in that, The casing is either an equipment casing or an aircraft casing.

4. An aircraft power system, characterized in that, The aircraft power system includes: a bus power supply, multiple power circuits, multiple load device circuits, a pyrotechnic ignition circuit, and a pyrotechnic and line insulation detection circuit. Each power circuit, each load device circuit, and the pyrotechnic ignition circuit is powered by the bus power supply. The pyrotechnic is ignited by the pyrotechnic ignition circuit. The line insulation detection circuit adopts the aircraft power system line insulation detection circuit as described in any one of claims 1 to 3.

5. The aircraft power system according to claim 4, characterized in that, The pyrotechnic ignition circuit includes a pyrotechnic ignition relay switch, which is connected to the positive line of the bus power supply, and the pyrotechnic is connected to the negative line of the bus power supply.

6. The aircraft power system according to claim 4, characterized in that, The pyrotechnic ignition circuit includes a first pyrotechnic semiconductor electronic switch and a second pyrotechnic semiconductor electronic switch. The first pyrotechnic semiconductor electronic switch is connected to the positive line of the bus power supply, and the second pyrotechnic semiconductor electronic switch is connected to the negative line of the bus power supply and the pyrotechnic device, respectively.

7. The aircraft power system according to any one of claims 4 to 6, characterized in that, The voltage of the DC test power supply in the line insulation detection circuit does not exceed the short-time maximum voltage that the aircraft power system can withstand.

8. The aircraft power system according to any one of claims 4 to 6, characterized in that, At least one load device circuit has a bridging resistor between the positive and negative power supply ports.

9. A method for detecting the insulation of an aircraft power system circuit, characterized in that, The method for detecting the insulation of the aircraft power system circuits uses the aircraft power system circuit insulation detection circuit as described in any one of claims 1 to 3 to perform circuit insulation detection.

10. The method for detecting the insulation of aircraft power system circuits according to claim 9, characterized in that, The method for detecting the insulation of the aircraft power system circuits includes: performing circuit insulation detection after the delay control period ends.

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