Fusing protection circuit

Abstract

The utility model belongs to the field of electrical control, and particularly relates to a fusing protection circuit with an active fusing function and a passive fusing function. When a fault of'turn-off and non-turn-off 'caused by failure of a system switch occurs, the whole anti-icing and deicing system stops working in the traditional method. The circuit comprises an input interface, a fuse, an output interface and a current sampling circuit which are connected in series, the output end of the fuse is further connected with an energy absorption load through a power switch, and the power switch is controlled through a power switch control circuit. The fuse can be actively fused when a system switch fails and a fault of'turn-off but not-turn-off 'occurs, or passively fused to cut off a load under the condition of overload or short circuit of the load.

Description

Technical Field

[0001] The utility model belongs to the field of electrical control, and specifically relates to a fuse protection circuit with active fusing functions and passive fusing functions. The circuit can actively fuse when a system switch fails and a "should be closed but is not closed" fault occurs, or passively fuse when a load is overloaded or short-circuited, thereby cutting off the load. Background Art

[0002] Aircraft anti-icing systems are crucial for ensuring safe operation. Due to the power limitations of the aircraft's power system, the anti-icing system's power distribution features multiple independent switches controlling independent heating components within the protected area. Independent heating components cannot operate simultaneously, so the anti-icing system must ensure that the previously active heating component is reliably shut down before the next heating component can be activated.

[0003] When a system switch failure occurs, resulting in a "should-be-off" failure, the traditional approach is to shut down the entire anti-icing system. This mode is not conducive to the anti-icing system's mission. Therefore, measures must be taken to address this "should-be-off" failure and maximize the anti-icing system's ability to complete its mission. Utility Model Content

[0004] The purpose of this utility model is to design a fuse protection circuit with active and passive fusing functions. It can passively fuse and cut off the load when the load is overloaded or short-circuited. It can also actively fuse and cut off the load when the system switch fails and a "should be closed but is not closed" fault occurs, thereby ensuring that other loads in the system can work normally.

[0005] The utility model proposes a fuse protection circuit, which is used to actively fuse when a system switch fails, or passively fuse when the load is overloaded or short-circuited, thereby cutting off the load. The circuit includes an input interface, a fuse, an output interface, and a current sampling circuit connected in series. An energy absorbing load is also connected to the output end of the fuse through a power switch, and the power switch is controlled by a power switch control circuit.

[0006] Advantageously, the input interface and the output interface are formed by power electrical connectors and have an overload capacity of three times the rated current within at least 200ms.

[0007] Advantageously, the input interface and the output interface need to meet the medium pressure resistance requirements under low pressure conditions.

[0008] Advantageously, the input interface is connected to an input terminal of a power source, and the output interface outputs the power source.

[0009] Advantageously, the current sampling circuit selects a current sensor based on the Hall principle.

[0010] Advantageously, a MOSFET is selected as the power switch.

[0011] Advantageously, the energy absorbing load is selected as a transient voltage suppressor diode.

[0012] The utility model has the advantages of having active fusing function and passive fusing function, cutting off the load when a fault occurs, degrading the system and ensuring the mission reliability of the system to the greatest extent. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is the structural principle diagram of this protection circuit. DETAILED DESCRIPTION

[0014] join Figure 1 The power supply is introduced through the input interface, passes through the fuse, and is output to the subsequent power load through the output interface. The current sampling circuit is used to collect the output current of the power supply and transmit the sampled value to the upper controller. The power switch and energy absorption load are located after the fuse. The power switch control circuit is used to drive the power switch on and off.

[0015] When the downstream power load is "should be turned off but is not" or the upstream protection switch fails, a control signal is actively input to the power switch control circuit. The power switch control circuit controls the power switch to turn on, and current flows through the fuse, power switch and energy absorption load. The large current generated at this time causes the fuse to melt, thereby cutting off the power load and achieving protection.

[0016] The input and output interfaces are composed of power electrical connectors. While meeting the rated operating current of the downstream power load, they must also have an overload capacity of three times the rated current for at least 200ms. Furthermore, to ensure the circuits function properly throughout the aircraft's entire flight envelope, the power electrical connectors must also meet dielectric withstand voltage requirements under low-pressure conditions.

[0017] According to the loop current sampling accuracy requirements, the current sampling circuit selects a current sensor based on the Hall principle, which can ensure electrical isolation between the power end and the demodulation end, and prevent the demodulation end from being affected by the power end.

[0018] In order to ensure the real-time operation of the power switch, MOSFET is selected as the power switch.

[0019] To ensure reusability and miniaturization, the energy-absorbing load uses a transient voltage suppressor (TVS) diode. When the power switch turns on, the TVS diode breaks down, generating a short-term, high current that flows through the fuse, forcing the fuse to blow and shutting off power to the circuit. The energy-absorbing load and fuse must be selected based on their respective VI and I²T curves to ensure the energy-absorbing load is not damaged during the fusing process and that the fuse can be reliably opened.

[0020] The power switch control circuit is provided with an integration circuit, which can output a drive signal to drive the power switch to conduct only under the condition of AC component input, so as to avoid the circuit being operated by an unstable state level or fault level when the controller is powered on.

[0021] The current sampling circuit collects and reports the "should-be-off" fault condition, which serves as the basis for fault diagnosis and feedback. The power switch and energy-absorbing load force the fuse to blow, preventing further spread of the fault. The energy-absorbing load's transient overload capacity is also utilized, making it reusable.

Claims

1. A fuse protection circuit, which is used to actively fuse when a system switch fails, or passively fuse when a load is overloaded or short-circuited, thereby disconnecting the load, characterized by: The circuit includes an input interface, a fuse, an output interface and a current sampling circuit connected in series. An energy absorbing load is also connected to the output end of the fuse through a power switch, and the power switch is controlled by a power switch control circuit.

2. The fuse protection circuit according to claim 1, wherein: The input interface and the output interface are composed of power electrical connectors and have an overload capacity of 3 times the rated current within at least 200ms.

3. The fuse protection circuit according to claim 2, wherein: The input interface and output interface must meet the medium pressure resistance requirements under low pressure conditions.

4. The fuse protection circuit according to claim 3, wherein: The input interface is connected to the input end of the power supply, and the output interface outputs the power supply.

5. The fuse protection circuit according to claim 1, wherein: The current sampling circuit selects a current sensor based on the Hall principle.

6. The fuse protection circuit according to claim 1, wherein: Select MOSFET as the power switch.

7. The fuse protection circuit according to claim 1, wherein: Select transient voltage suppression diodes for energy absorbing loads.

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