Electrical circuit state monitoring unit and device

Abstract

The electrical circuit state monitoring unit comprises a frequency mixer unit, a filtering unit, an excitation voltage generator, an isolation transformer, an AC signal source and a clock signal source. The excitation voltage generator is connected with a tested circuit, a primary winding of the isolation transformer is connected in parallel with the excitation voltage generator, and a secondary winding is connected in parallel with an AC signal source. The input end of the clock signal source is connected in series between the isolation transformer and the AC signal source, and the output end is connected with the mixer unit which is connected with the filtering unit. The indication of the state of the system wire and the EMC filter can be provided in advance before the electrical circuit breaks down and the normal operation of the whole electrical system is influenced, so that the fault prevention of the electrical system can be realized.

Description

Technical Field

[0001] The utility model relates to the technical field of electronic circuits, and in particular to an electrical circuit state monitoring unit and a device. Background Art

[0002] The rapid advancement of technology in modern vehicles, particularly aircraft and automobiles, has led to unprecedented complexity and sophistication in their internal circuit systems. These electrical systems, comprising vast networks of wires, form the core of the vehicle's electronic architecture, ensuring the proper functioning of every function, from signal transmission to power control. However, the integrity of these wires and their insulation is severely challenged by harsh operating environments characterized by extreme temperature fluctuations, constant mechanical vibration, and potential chemical corrosion.

[0003] The aging or damage of insulating materials can directly lead to electrical faults such as short circuits between conductors and arc discharges, which in turn affect the stability and safety of the entire system and reduce the reliability and service life of the vehicle. Traditional maintenance strategies, namely regular inspections based on time periods and passive repairs after faults, can identify and solve existing problems to a certain extent, but their limitations are becoming increasingly prominent. First, the inspection cycle under this model is often longer than the actual fault occurrence cycle, making it difficult to monitor potential risks in real time; second, for electrical problems that are highly hidden and difficult to detect in the early stages, regular inspections may miss the best time to intervene, and the problem may not be discovered until it escalates into a major accident, at which point the repair cost and safety risks are greatly increased. In addition, existing technologies are often unable to simultaneously monitor line faults while the electrical system is in use and during power outages, which greatly reduces the reliability and efficiency of monitoring. Utility Model Content

[0004] The purpose of the embodiments of the present utility model is to provide an electrical circuit status monitoring unit and device to provide an indication of the status of the system conductors and filters before the electrical circuit fails and affects the normal operation of the entire electrical system, thereby preventing electrical system failures.

[0005] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0006] An electrical circuit status monitoring unit includes a mixer unit, a filter unit, an excitation voltage generator, an isolation transformer, an AC signal source, and a clock signal source; the excitation voltage generator is connected to a circuit under test, the primary winding of the isolation transformer is connected in parallel to the excitation voltage generator, and the secondary winding is connected in parallel to the AC signal source; the input end of the clock signal source is connected in series between the isolation transformer and the AC signal source, and the output end is connected to the mixer unit, which is connected to the filter unit.

[0007] Furthermore, the excitation voltage generator is arranged in series between the circuit under test and the supporting structure.

[0008] Furthermore, a measuring resistor is arranged in series between the excitation voltage generator and the supporting structure.

[0009] Furthermore, the isolation device is arranged in parallel with the measuring resistor; the isolation device is also connected to the mixer unit.

[0010] Furthermore, the isolation device is specifically an isolation operational amplifier or a transformer with an isolation function.

[0011] Furthermore, the mixer unit includes a first mixer and a second mixer, and the output end of the clock signal source is connected to the first mixer and the second mixer respectively.

[0012] Furthermore, the filtering unit includes a first low-pass filter and a second low-pass filter; the first low-pass filter is connected in series with the first mixer; and the second low-pass filter is connected in series with the second mixer.

[0013] Furthermore, the signal frequency of the AC signal source is the same as the voltage frequency generated by the excitation voltage generator.

[0014] Furthermore, a capacitor is provided between the excitation voltage generator and the circuit under test; the circuit under test includes a conductor or an EMC filter capacitor.

[0015] An electrical circuit state monitoring device comprises the electrical circuit state monitoring unit.

[0016] Compared with the prior art, the present invention has the following technical effects:

[0017] Preventive maintenance: It can provide an indication of the status of system conductors and EMC filters in advance before electrical circuit faults occur and affect the normal operation of the entire electrical system, helping to prevent electrical system faults.

[0018] Continuous monitoring capability: It can monitor the electrical system in both online (energized) and offline (de-energized) states, realizing continuous monitoring of the electrical system status and improving the reliability and efficiency of monitoring.

[0019] Improved accuracy: By measuring the resistance and capacitance between the circuit under test and the load-bearing structure, the in-phase (Ii) and quadrature (Iq) currents are used to analyze the condition of conductors and EMC filters. This method is more accurate and can detect potential electrical problems in a timely manner.

[0020] Wide applicability: Suitable for electrical system monitoring in vehicles such as automobiles and aircraft, helping to improve the overall reliability and safety of vehicles.

[0021] Non-intrusive monitoring: The electrical system is monitored through electrical isolation, avoiding interference or safety hazards that may be caused by direct electrical connection.

[0022] Easy to integrate: The monitoring unit is designed to be easily integrated into existing electrical systems, eliminating the need for large-scale modifications to the original system and reducing implementation difficulty and cost.

[0023] In summary, the present invention can effectively improve the reliability and safety of the electrical system of a vehicle and reduce the maintenance costs and safety risks caused by electrical failures. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0025] Figure 1 is a schematic diagram of an electrical circuit status monitoring unit according to this embodiment;

[0026] Among them, 1. Circuit under test; 2. Isolation transformer; 3. AC signal source; 4. Clock signal source; 5. First low-pass filter; 6. Second low-pass filter; 7. First mixer; 8. Second mixer; 9. Isolation device; 10. Measuring resistor; 11. Carrying structure; 12. Excitation voltage generator; 13. Capacitor. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0028] The electrical line status monitoring unit provided in this embodiment can provide an indication of the status of each wire (and possible EMC (electromagnetic compatibility) filter) in the electrical system of an automobile, aircraft, or other means of transportation before the line (and possible EMC (electromagnetic compatibility) filter) fails and affects the normal operation of the electrical system.

[0029] In some specific embodiments, the status of the electrical system wires and any EMC filters is checked by measuring the resistance and capacitance of the electrical system wires relative to the electrical system's supporting structure 11 (typically a metal frame, which also includes but is not limited to the housing supporting the electrical system and the main frame of the vehicle carrying the electrical system). Specifically, the measurement is performed using high-frequency alternating current. In this embodiment, this measurement can be performed both online (energized) and offline (de-energized) for the electrical system, thereby enabling continuous monitoring of the electrical system's status.

[0030] Figure 1 This is a schematic diagram of the electrical circuit status monitoring unit in this embodiment. This unit can monitor both direct current (DC) and alternating current (AC) circuits in the system. Specifically, it performs analysis by measuring the resistance (R) and capacitance (C) between the circuit under test 1 and the support structure 11.

[0031] In this embodiment, the supporting structure 11 includes but is not limited to the supporting structure 11 of the vehicle, metal frame, frame and other structures. The supporting structure 11 is a necessary structure for the electrical system to be carried in a car, spacecraft or other vehicle and realize its function.

[0032] In some specific implementations, electrical isolation needs to be implemented between the electrical circuit status monitoring unit and the circuit under test 1 and the supporting structure 11 to ensure that there is no direct electrical connection path between the electrical circuit status monitoring unit and the circuit under test 1 and the supporting structure 11.

[0033] like Figure 1 As shown, an excitation voltage generator 12 is provided to apply a sinusoidal voltage to the circuit under test 1 and the supporting structure 11 to drive the operation of the electrical circuit state monitoring unit. One end of the excitation voltage generator 12 is connected to the circuit under test 1, and the other end is connected to the supporting structure 11. In this embodiment, an isolation transformer 2 is provided to isolate the excitation voltage generator 12, thereby achieving electrical isolation of the above-mentioned electrical circuit state monitoring unit.

[0034] In some specific embodiments, the primary winding of the isolation transformer 2 is connected in parallel with the excitation voltage generator 12, and the secondary winding is connected in parallel with an AC signal source 3 with the same frequency as the excitation voltage generator 12; to ensure that the operating frequency of the isolation transformer 2 is the same as the frequency of the sinusoidal voltage generated by the excitation voltage generator 12.

[0035] The current flowing in the secondary winding of the isolation transformer 2 is proportional to the voltage thereof and inversely proportional to the total reactance and resistance between the circuit under test 1 and the supporting structure 11. In some specific embodiments, the total reactance between the circuit under test 1 and the supporting structure 11 is determined by the characteristics of the circuit under test 1, the insulation state of the circuit under test 1, and the EMC filter capacitor (if any).

[0036] Therefore, the current flowing through the secondary winding measures the reactance and resistance of the circuit under test 1 relative to the metal frame, allowing the health of the circuit under test 1 and any EMC filters present to be determined. Furthermore, the current flowing through the secondary winding depends on the parameters of the isolation transformer 2; these parameters are typically fixed and known for a specific transformer, and can therefore be considered constant during the measurement process, unaffected by time.

[0037] In some possible embodiments, in order to measure the current that changes with the capacitance of the circuit under test 1 relative to the supporting structure 11 and the resistance between the circuit under test 1 and the supporting structure 11, a measuring resistor 10 is arranged between the excitation voltage generator 12 and the supporting structure 11, and a device (isolating device 9) capable of isolating the voltage across the measuring resistor 10 is arranged at both ends of the measuring resistor 10 to isolate the voltage across the measuring resistor 10.

[0038] In some possible implementations, the isolation device 9 includes an isolation operational amplifier connected in parallel across the measuring resistor 10 .

[0039] In some possible implementations, the isolation device 9 may also be a transformer with an isolation function connected in parallel across the measuring resistor 10 .

[0040] In some specific embodiments, the current flowing between the circuit under test 1 and the supporting structure 11 has a phase difference with respect to the excitation voltage applied between the circuit under test 1 and the supporting structure 11. This current can be analyzed by measuring its two components: a component (Ii) that is in phase with the excitation voltage and a component (Iq) that is orthogonal to the excitation voltage.

[0041] The in-phase current (Ii) is proportional to the excitation voltage and inversely proportional to the resistance between the circuit under test 1 and the load-bearing structure 11. The quadrature current (Iq) is proportional to the excitation voltage and inversely proportional to the reactance between the conductor under test and the load-bearing structure 11. Therefore, by measuring Ii, the resistance of the conductor under test and the load-bearing structure 11 can be determined; by measuring Iq, the state of the dielectric and EMC filter (if any) of the circuit under test 1 can be determined.

[0042] The current I flowing between the circuit under test 1 and the carrier structure 11 generates a voltage drop Vcdt across the measuring resistor 10R, i.e., Vcdt = R * I. I can be decomposed into two components, Ii and Iq. Therefore, Vcdt can also be decomposed into an in-phase component and quadrature components, Vi and Vq. To obtain the two components of the voltage drop, a first mixer 7 and a second mixer 8 are connected in series with the device used to isolate the voltage across the measuring resistor 10. The first mixer 7 and the second mixer 8 are connected in parallel, and a first low-pass filter 5 and a second low-pass filter 6 are provided at the outputs of the first mixer 7 and the second mixer 8, respectively. The two mixers receive the isolation voltage (corresponding to the isolation voltage of Vcdt) output by the isolation device 9 at their inputs.

[0043] This embodiment also provides a clock signal source 4 on the secondary winding of the isolation transformer 2. This clock signal source 4 splits the sinusoidal signal input from the secondary winding into two paths, one with a phase difference of 0° and the other with a phase difference of 90°. These signals are fed into a first mixer 7 and a second mixer 8, respectively. A square wave signal (0°) in phase with the excitation voltage is fed into the first mixer 7 for detecting Vi, while a signal with a phase difference of 90° from the excitation voltage is fed into the second mixer 8 for detecting Vq. Two low-pass filters allow only the DC component to pass, blocking the AC component.

[0044] In some possible implementations, both the first mixer 7 and the second mixer 8 may be replaced by multipliers.

[0045] In some possible implementations, a capacitor 13 is provided between the excitation voltage generator 12 and the circuit under test 1. If the circuit under test 1 transmits direct current, the isolation transformer 2 or, if present, the isolation transformer connected in parallel with the measuring resistor 10 may saturate, resulting in reduced transformer efficiency, increased transformer losses and overheating, or an unexpected voltage generated in the secondary winding. To avoid potential transformer saturation, capacitor 13 is used to filter the DC component of the DC current or to provide the current with a certain AC component through other means to ensure proper operation of the transformer.

[0046] By measuring Vi, the resistance of the conductor under test and the load-bearing structure 11 can be determined; by measuring Vq, the health of the dielectric and / or EMC filter of the line under test can be determined. These two values, Vi and Vq, are the "signatures" of the circuit; changes in these values ​​indicate abnormal conditions in the cable and / or its connected equipment.

[0047] The above description is only a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention are included in the scope of protection of the present invention.

Claims

1. An electrical line status monitoring unit, characterized in that: The invention comprises a mixer unit, a filter unit, an excitation voltage generator (12), an isolation transformer (2), an AC signal source (3) and a clock signal source (4); the excitation voltage generator (12) is connected to the circuit under test, the primary winding of the isolation transformer (2) is connected in parallel to the excitation voltage generator (12), and the secondary winding is connected in parallel to the AC signal source (3); the input end of the clock signal source (4) is connected in series between the isolation transformer (2) and the AC signal source (3), and the output end is connected to the mixer unit, and the mixer unit is connected to the filter unit.

2. An electrical line status monitoring unit according to claim 1, characterized in that: The excitation voltage generator (12) is arranged in series between the circuit under test (1) and the bearing structure (11).

3. An electrical line status monitoring unit according to claim 2, characterized in that: The measuring resistor (10) is arranged in series between the excitation voltage generator (12) and the supporting structure (11).

4. An electrical line status monitoring unit according to claim 2, characterized in that: The isolation device (9) is arranged in parallel with the measuring resistor (10); the isolation device (9) is also connected to the mixer unit.

5. An electrical line status monitoring unit according to claim 4, characterized in that: The isolation device (9) is specifically an isolation operational amplifier or a transformer with an isolation function.

6. The electrical line status monitoring unit according to claim 1, characterized in that: The mixer unit comprises a first mixer (7) and a second mixer (8), and the output end of the clock signal source (4) is connected to the first mixer (7) and the second mixer (8) respectively.

7. An electrical line status monitoring unit according to claim 6, characterized in that: The filtering unit comprises a first low-pass filter (5) and a second low-pass filter (6); the first low-pass filter (5) is connected in series with the first mixer (7); and the second low-pass filter (6) is connected in series with the second mixer (8).

8. The electrical line status monitoring unit according to claim 1, characterized in that: The signal frequency of the AC signal source (3) is the same as the voltage frequency generated by the excitation voltage generator (12).

9. The electrical line status monitoring unit according to claim 1, characterized in that: A capacitor (13) is provided between the excitation voltage generator (12) and the circuit under test (1); the circuit under test (1) includes a conductor or an EMC filter capacitor.

10. An electrical line status monitoring device, characterized in that: The device comprises an electrical line status monitoring unit according to any one of claims 1 to 9.

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