An aviation emergency battery SOH detection system and method

Abstract

The present invention belongs to the technical field of aviation power supply system, and discloses an aviation emergency battery SOH detection system and method, which generates a short-term large-rate constant current to detect the voltage change of the battery through hardware circuit design, so as to quickly calculate the internal resistance of the battery and obtain the SOH of the battery. The method has a fast detection time and can be completed without a large amount of discharge of the battery, which can effectively improve the detection efficiency and reduce the detection cost.

Description

Technical Field

[0001] The present invention belongs to the technical field of emergency battery subsystems in aviation power supply systems, and in particular relates to an aviation emergency battery SOH detection system and method. Background Art

[0002] The main purpose of aviation emergency batteries is to serve as auxiliary power or emergency power to supply power to important electrical equipment when the main power supply of the aircraft is not working or fails. Its importance is self-evident. Therefore, it is necessary to monitor the health status of aviation emergency batteries regularly. The health status or state of the battery can be expressed by SOH (State of Health). There are internal resistance method, capacity method and other methods to detect battery SOH. The capacity method judges SOH by discharging the battery and comparing the current battery power with the battery power when it leaves the factory. This detection method is suitable for working conditions with frequent charging and discharging, such as the power battery of electric vehicles and the battery of mobile communication equipment. These devices are usually charged and discharged every day or every few days, which is convenient for detection. However, the aviation emergency battery is unloaded under normal aircraft conditions and does not need to be cyclically charged and discharged. It is only discharged when the main power supply is abnormal. It takes a long time to estimate SOH using the capacity detection method, and there are few working conditions on the emergency battery. Therefore, it is not suitable to use the capacity method to measure the SOH of aircraft emergency batteries. In summary, a reliable and rapid method for detecting the SOH of aviation emergency batteries is needed.

[0003] In order to quickly detect the SOH of an aircraft emergency battery, the present invention proposes a method for detecting the SOH of an aircraft emergency battery by measuring the internal resistance of the battery. The method has a fast detection time and can be completed without a large amount of discharge of the battery. It can effectively improve the detection efficiency and reduce the detection cost. Summary of the invention

[0004] The present invention provides an aviation emergency battery SOH detection system and method, which can quickly detect the aviation emergency battery SOH without affecting the normal dispatch of the aircraft and without the need for complete discharge.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] An aviation emergency battery SOH detection system, comprising:

[0007] A power circuit consisting of a MOSFET, a thick film resistor and a shunt connected in series;

[0008] An operational amplifier, used for collecting the current of the power circuit;

[0009] a timing circuit; and a constant current control module, which is mainly used to adjust the current and receive the signals transmitted by the operational amplifier and the timing circuit.

[0010] As a further technical solution of the present invention, two parallel-connected MOSFETs are arranged in the power circuit.

[0011] As a further technical solution of the present invention, the MOSFETT operates in a variable resistance region.

[0012] As a further technical solution of the present invention, the thick film resistor is used to disperse heat.

[0013] An aviation emergency battery SOH detection method, using the above detection system, comprises the following steps:

[0014] Step 1: When testing is required, first close the battery positive circuit breaker to ensure that there are no other switching devices in the power circuit except MOSFET;

[0015] Step 2: The external input detection command starts the timing circuit, and the preset reference voltage is added to the positive input terminal of the operational amplifier at the front end of the MOSFET gate;

[0016] Step 3: MOSFET starts working, the power circuit is connected, and current begins to flow;

[0017] Step 4: While the power circuit is working, the shunt in the power loop starts to collect the loop current, converts the current signal into a voltage signal, and outputs it after amplification by the operational amplifier;

[0018] Step 5: Compare the voltage signal corresponding to the current signal collected above with the reference voltage preset in step 2, and always stably control the output current at a preset value;

[0019] Step 6: Drive the MOSFET according to the result of the comparison in step 5. At this time, the MOSFET works in the variable resistance area. The resistance of the MOSFET is controlled by the change of the driving voltage, thereby stabilizing the current of the control loop.

[0020] Step 7: Monitor the battery voltage in real time. When a high-rate constant current value is generated, the voltage will have a significant difference. The internal resistance of the battery can be calculated through the change in voltage and the value of the constant current, thereby inferring the battery's SOH.

[0021] As a further technical solution of the present invention, in step 2, the reference voltage is provided by the timing circuit.

[0022] As a further technical solution of the present invention, it also includes a timing step, in which the high-rate discharge time is controlled by a timing circuit, and the constant current power circuit is automatically powered off after the test is completed.

[0023] As a further technical solution of the present invention, in step 6, the resistance of MOSFET is controlled by changing the driving voltage as follows: if the collected value is larger than the reference value, MOSFET is controlled to increase its resistance; if the collected value is smaller than the reference value, MOSFET is controlled to decrease its resistance, so that the power circuit obtains a constant current value.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1. This method can quickly detect the SOH of aviation emergency batteries without affecting the normal dispatch of the aircraft and without the need for complete discharge. It has fast detection speed and low detection cost. It is suitable for SOH detection of emergency batteries and improves the reliability of aviation power supply systems.

[0026] 2. A design method for controlling the generation of a constant current source using the variable resistance area of ​​MOSFET. Two MOSFETs are connected in parallel to control the constant current source circuit, and a thick film resistor is connected in series to the power circuit. These two parts of the circuit are used to disperse the heat generated by the power circuit and improve the circuit stability.

[0027] 3. At the same time, current collection and amplification are designed in the control circuit, and the constant current source is controlled to stabilize the output by comparing with a reference voltage input.

[0028] 4. A timing circuit is designed at the control input end to ensure that the power circuit is immediately powered off after the detection is completed to prevent over-discharge of the battery and continuous heating of the device.

[0029] 5. The present invention realizes a method for quickly obtaining the SOH of an aviation emergency battery by detecting the internal resistance of the battery, thereby improving the detection efficiency of the SOH of the emergency battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic block diagram of the SOH detection principle of the present invention. DETAILED DESCRIPTION

[0031] 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 described embodiments 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 creative work are within the scope of protection of the present invention.

[0032] First, see Figure 1 The present invention provides an aviation emergency battery SOH detection system, which comprises:

[0033] A power circuit consisting of a MOSFET, a thick film resistor and a shunt connected in series;

[0034] An operational amplifier, used for collecting the current of the power circuit;

[0035] A timing circuit; and a constant current control module, which is mainly used to adjust the current and receive the signal transmitted by the operational amplifier and the timing circuit. The constant current control module controls the constant current output by continuously comparing the input reference voltage and the voltage signal converted by the collected current.

[0036] The constant current control module compares the reference voltage value with the voltage value corresponding to the collected current. If the collected value is larger than the reference value, the MOSFET is controlled to increase its resistance; if the collected value is smaller than the reference value, the MOSFET is controlled to reduce its resistance, thereby obtaining a constant current value.

[0037] In this embodiment, two parallel MOSFETs are provided in the power circuit, and the MOSFETT works in the variable resistance region. A plurality of thick film resistors are provided to disperse heat.

[0038] There is a corresponding relationship between the health status of the battery and the internal resistance. When the battery is tested at the factory, the corresponding relationship between the internal resistance and SOH will be obtained. During subsequent use, the battery SOH can be estimated by detecting the internal resistance.

[0039] This solution uses hardware circuit design to generate a short-term high-rate constant current to detect the voltage change of the battery, so that the internal resistance of the battery can be quickly calculated, and then the SOH of the battery can be obtained. The specific implementation method is as follows:

[0040] 1. Generate a constant current source by controlling MOSFET to work in the variable resistance area; the MOSFET variable resistance area is equivalent to the amplification area of ​​MOSFET. In the variable resistance area, the gate voltage of MOSFET controls the source leakage current, so the resistance value can be controlled. In the variable resistance area, when the gate voltage increases, the source leakage current increases significantly, the resistance value decreases, and the output voltage decreases. When the gate voltage decreases, the source leakage current decreases, the resistance value increases, and the output voltage rises. Therefore, this design uses this feature of MOSFET to control the generation of constant current.

[0041] 2. Due to the high-rate discharge during discharge, the power circuit devices will generate a lot of heat. In order to reduce the heat generation of MOSFET, a thick-film resistor is connected in series in the constant current source circuit to disperse the power on the MOSFET, reduce the consequences of device damage due to severe heat generation, and improve the reliability of the circuit.

[0042] 3. The sampling resistor converts the current signal of the power circuit into a voltage signal. Since the sampling resistor is very small, the converted voltage value is also very low, which is not conducive to the processing of the subsequent control circuit. Therefore, this tiny voltage signal is amplified by the operational amplifier, and then compared with the set reference value and output as the drive of the MOSFET, thereby generating a stable constant current source.

[0043] 4. To measure the internal resistance, you only need to measure the voltage drop on the battery after the constant current source is generated. Due to the high-rate discharge, the heat loss of the power circuit components is large, and long-term discharge may damage the components. Therefore, long-term discharge is not required. This solution controls the high-rate discharge time through a timing circuit, and the constant current power circuit is automatically powered off after the test is completed.

[0044] Secondly, the aviation emergency battery needs to be regularly monitored for its health status to ensure the flight safety of the aircraft. The present invention provides an aviation emergency battery SOH detection method, which includes the following steps:

[0045] Step 1: When testing is required, first close the battery positive circuit breaker to ensure that there are no other switching devices in the power circuit except MOSFET;

[0046] Step 2: The external input detection command starts the timing circuit, and the preset reference voltage is added to the positive input terminal of the operational amplifier at the front end of the MOSFET gate;

[0047] Step 3: MOSFET starts working, the power circuit is connected, and current begins to flow;

[0048] Step 4: While the power circuit is working, the shunt in the power loop starts to collect the loop current, converts the current signal into a voltage signal, and outputs it after amplification by the operational amplifier;

[0049] Step 5: Compare the voltage signal corresponding to the current signal collected above with the reference voltage preset in step 2, and always stably control the output current at a preset value;

[0050] Step 6: Drive the MOSFET based on the comparison result in step 5. At this time, the MOSFET works in the variable resistance area. The resistance of the MOSFET is controlled by the change of the driving voltage, so as to stabilize the current of the control loop. Specifically, if the collected value is larger than the reference value, the MOSFET is controlled to increase its resistance; if the collected value is smaller than the reference value, the MOSFET is controlled to reduce its resistance, so that the power circuit obtains a constant current value.

[0051] Step 7: Monitor the battery voltage in real time. When a high-rate constant current value is generated, the voltage will have a significant difference. The internal resistance of the battery can be calculated through the change in voltage and the value of the constant current, thereby inferring the battery's SOH.

[0052] The timing step controls the high-rate discharge time through the timing circuit, and the constant current power circuit is automatically powered off after the test is completed. The above detection process only takes a few seconds to complete. Through the setting of the timing circuit, after 10 seconds, the timing ends, the MOSFET drive voltage immediately drops to 0, the MOSFET stops working, the power circuit is disconnected, and the battery internal resistance inspection is completed.

[0053] So far, the purpose of the present invention has been achieved.

[0054] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

Claims

1. An aviation emergency battery SOH detection system, characterized in that ,include: A power circuit consisting of a MOSFET, a thick film resistor and a shunt connected in series; An operational amplifier, used for collecting the current of the power circuit; Timing circuit; And a constant current control module, which is mainly used to adjust the current and receive the signals transmitted by the operational amplifier and the timing circuit.

2. The aviation emergency battery SOH detection system according to claim 1 is characterized in that: Two parallel-connected MOSFETs are arranged in the power circuit.

3. The aviation emergency battery SOH detection system according to claim 2 is characterized in that: The MOSFET T operates in a variable resistance region.

4. The aviation emergency battery SOH detection system according to claim 3 is characterized in that: The thick film resistors are used to dissipate heat.

5. A method for detecting SOH of an aviation emergency battery, using the detection system of claim 4, characterized in that: The steps include: Step 1: When testing is required, first close the battery positive circuit breaker to ensure that there are no other switching devices in the power circuit except MOSFET; Step 2: The external input detection command starts the timing circuit, and the preset reference voltage is added to the positive input terminal of the operational amplifier at the front end of the MOSFET gate; Step 3: MOSFET starts working, the power circuit is connected, and current begins to flow; Step 4: While the power circuit is working, the shunt in the power loop starts to collect the loop current, converts the current signal into a voltage signal, and outputs it after amplification by the operational amplifier; Step 5: Compare the voltage signal corresponding to the current signal collected above with the reference voltage preset in step 2, and always stably control the output current at a preset value; Step 6: Drive the MOSFET according to the result of the comparison in step 5. At this time, the MOSFET works in the variable resistance area. The resistance of the MOSFET is controlled by the change of the driving voltage, thereby stabilizing the current of the control loop. Step 7: Monitor the battery voltage in real time. When a high-rate constant current value is generated, the voltage will have a significant difference. The internal resistance of the battery can be calculated through the change in voltage and the value of the constant current, thereby inferring the battery's SOH.

6. The aviation emergency battery SOH detection method according to claim 5, characterized in that: In the step 2, a reference voltage is provided by the timing circuit.

7. The aviation emergency battery SOH detection method according to claim 6 is characterized in that: It also includes a timing step, in which the high-rate discharge time is controlled by a timing circuit, and the constant current power circuit is automatically powered off after the test is completed.

8. The aviation emergency battery SOH detection method according to claim 7, characterized in that: In step 6, the resistance of MOSFET is controlled by changing the driving voltage. Specifically, if the collected value is larger than the reference value, MOSFET is controlled to increase its resistance; if the collected value is smaller than the reference value, MOSFET is controlled to decrease its resistance, so that the power circuit obtains a constant current value.

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