Fault detection circuit, method and system

Abstract

The present application discloses a fault detection circuit, method and system. The fault detection circuit includes an access unit and an oscillation unit. The access unit is configured to connect the winding of a speed sensor to the oscillation unit. The oscillation unit is configured to generate or not generate an oscillation signal according to the state of the winding, so that it is determined whether the winding is broken according to the presence or absence of the oscillation signal. The fault detection circuit, method and system can automatically detect whether the winding of the speed sensor is broken when the vehicle is stationary, thereby improving the safety of the vehicle.

Description

Technical Field

[0001] The present application relates to the field of fault detection, and in particular to a fault detection circuit, method and system. Background Art

[0002] During the operation of high-speed trains, the onboard system must constantly obtain speed information through the speed sensors installed on the axles. However, the speed sensors can only obtain speed information after the axles are running, using the law of electromagnetic induction. However, this inevitably leads to a serious problem, that is, once the train has a disconnection problem or a short circuit problem in a static state, the problem point can only be discovered during the operation of the train. Without speed information, high-speed trains will not be able to operate normally, resulting in train delays, and even worse, causing safety hazards. Summary of the invention

[0003] The present application provides a fault detection circuit, method and system, which can automatically detect whether a winding of a speed sensor is broken when the vehicle is stationary, thereby improving the safety of the vehicle.

[0004] The present application provides a fault detection circuit, which is applied to a speed sensor.

[0005] The fault detection circuit comprises an access unit and an oscillation unit;

[0006] The connecting unit is configured to connect the winding of the speed sensor to the oscillation unit;

[0007] The oscillation unit is configured to generate or not generate an oscillation signal according to the state of the winding, so that whether the winding is broken can be determined based on the presence or absence of the oscillation signal.

[0008] In an exemplary embodiment, the circuit further includes an inverting amplification unit;

[0009] The inverting amplifier unit is configured to invert and amplify the oscillation signal and output the amplified signal.

[0010] In an exemplary embodiment, the circuit further includes an optical coupling isolation unit;

[0011] The optical coupling isolation unit is configured to isolate the circuit from other circuits.

[0012] In an exemplary embodiment, the oscillation unit includes a first NPN transistor, a second NPN transistor, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, a first capacitor, a second capacitor, a first diode, a second diode and a DC power supply;

[0013] The collector of the first NPN transistor is connected to the DC power supply through a fourth resistor; the base of the first NPN transistor is connected to the first end of the third resistor; the emitter of the first NPN transistor is connected to the anode of the first diode;

[0014] The second end of the third resistor is connected to the first end of the first resistor and the first end of the second resistor respectively; the second end of the second resistor is connected to the DC power supply; the cathode of the first diode is connected to the first end of the sixth resistor;

[0015] The collector of the second NPN transistor is connected to the DC power supply through the fifth resistor; the base of the second NPN transistor is connected to the first end of the seventh resistor; the emitter of the second NPN transistor is connected to the anode of the second diode;

[0016] The second end of the third resistor is connected to the first end of the eighth resistor and the first end of the ninth resistor respectively; the second end of the eighth resistor is connected to the DC power supply; the cathode of the second diode is connected to the first end of the sixth resistor;

[0017] The collector of the first NPN transistor and the base of the second NPN transistor are connected via the first capacitor; the second capacitor is connected in parallel with the ninth resistor;

[0018] The second end of the sixth resistor is connected to the second end of the ninth resistor;

[0019] The second end of the first resistor and the second end of the sixth resistor are input ends of the oscillation unit; the collector of the second NPN transistor and the second end of the ninth resistor are output ends of the oscillation unit.

[0020] In an exemplary embodiment, the access unit includes a tenth resistor, an eleventh resistor and a third diode;

[0021] The tenth resistor is connected in series with the eleventh resistor;

[0022] The tenth resistor and the eleventh resistor connected in series are connected in parallel with the third diode; the non-common end of the tenth resistor is connected to the anode of the third diode;

[0023] The first end of the tenth resistor and the second end of the tenth resistor are input ends of the access unit; the anode and cathode of the third diode are output ends of the access unit.

[0024] The present application provides a fault detection method, comprising:

[0025] Acquire an output signal of a fault detection circuit; wherein the fault detection circuit is a circuit according to any one of claims 1 to 5;

[0026] It is determined whether the winding of the speed sensor is broken according to the output signal.

[0027] In an exemplary embodiment, judging whether the winding is broken according to the output signal includes:

[0028] If the output signal is a square wave signal, it is determined that the winding is not broken.

[0029] In an exemplary embodiment, judging whether the winding is broken according to the output signal includes:

[0030] If the output signal is not a square wave signal, it is determined that the winding is broken.

[0031] In an exemplary embodiment, it further includes:

[0032] When the vehicle equipped with the speed sensor is in a driving state, the current driving speed of the vehicle is calculated according to the square wave signal.

[0033] The present application provides a fault detection system, which is applied to a speed sensor, comprising:

[0034] Including fault detection circuit and MCU;

[0035] The fault detection circuit is a circuit as described in any one of claims 1 to 5;

[0036] The MCU is configured to obtain an output signal of the fault detection circuit, and determine whether the winding of the speed sensor is broken according to the output signal.

[0037] This application includes the following advantages:

[0038] At least one embodiment of the present application can automatically detect whether a winding of a speed sensor is broken when the vehicle is stationary, thereby improving the safety of the vehicle.

[0039] In one implementation of the embodiment of the present application, the speed of the vehicle can be measured while the vehicle is in motion.

[0040] Of course, any product implementing the present application does not necessarily need to achieve all of the advantages described above at the same time.

[0041] Other features and advantages of the present application will be described in the following description, and partly become apparent from the description, or be understood by implementing the present application. Other advantages of the present application can be realized and obtained by the schemes described in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The accompanying drawings are used to provide an understanding of the technical solution of the present application and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the technical solution of the present application and do not constitute a limitation on the technical solution of the present application.

[0043] Figure 1 A schematic diagram of a fault detection circuit according to an embodiment of the present application;

[0044] Figure 2 A flowchart of a fault detection method according to an embodiment of the present application;

[0045] Figure 3 A schematic diagram of a fault detection system according to an embodiment of the present application;

[0046] Figure 4 A schematic diagram of an oscillating waveform shaping circuit according to an embodiment of the present application;

[0047] Figure 5 A schematic diagram of an access unit according to an embodiment of the present application;

[0048] Figure 6 is a schematic diagram of an oscillation unit according to an embodiment of the present application. DETAILED DESCRIPTION

[0049] Figure 1 is a schematic diagram of a fault detection circuit according to an embodiment of the present application, such as Figure 1 As shown, the fault detection circuit of this embodiment includes an access unit and an oscillation unit;

[0050] The connecting unit is configured to connect the winding of the speed sensor to the oscillation unit;

[0051] The oscillation unit is configured to generate or not generate an oscillation signal according to the state of the winding, so that whether the winding is broken can be determined based on the presence or absence of the oscillation signal.

[0052] In an exemplary embodiment, the circuit further includes an inverting amplification unit;

[0053] The inverting amplifier unit is configured to invert and amplify the oscillation signal and output the amplified signal.

[0054] In an exemplary embodiment, the circuit further includes an optical coupling isolation unit;

[0055] The optical coupling isolation unit is configured to isolate the circuit from other circuits.

[0056] In an exemplary embodiment, the oscillation unit includes a first NPN transistor, a second NPN transistor, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, a first capacitor, a second capacitor, a first diode, a second diode and a DC power supply;

[0057] The collector of the first NPN transistor is connected to the DC power supply through a fourth resistor; the base of the first NPN transistor is connected to the first end of the third resistor; the emitter of the first NPN transistor is connected to the anode of the first diode;

[0058] The second end of the third resistor is connected to the first end of the first resistor and the first end of the second resistor respectively; the second end of the second resistor is connected to the DC power supply; the cathode of the first diode is connected to the first end of the sixth resistor;

[0059] The collector of the second NPN transistor is connected to the DC power supply through the fifth resistor; the base of the second NPN transistor is connected to the first end of the seventh resistor; the emitter of the second NPN transistor is connected to the anode of the second diode;

[0060] The second end of the third resistor is connected to the first end of the eighth resistor and the first end of the ninth resistor respectively; the second end of the eighth resistor is connected to the DC power supply; the cathode of the second diode is connected to the first end of the sixth resistor;

[0061] The collector of the first NPN transistor and the base of the second NPN transistor are connected via the first capacitor; the second capacitor is connected in parallel with the ninth resistor;

[0062] The second end of the sixth resistor is connected to the second end of the ninth resistor;

[0063] The second end of the first resistor and the second end of the sixth resistor are input ends of the oscillation unit; the collector of the second NPN transistor and the second end of the ninth resistor are output ends of the oscillation unit.

[0064] In an exemplary embodiment, the access unit includes a tenth resistor, an eleventh resistor and a third diode;

[0065] The tenth resistor is connected in series with the eleventh resistor;

[0066] The tenth resistor and the eleventh resistor connected in series are connected in parallel with the third diode; the non-common end of the tenth resistor is connected to the anode of the third diode;

[0067] The first end of the tenth resistor and the second end of the tenth resistor are input ends of the access unit; the anode and cathode of the third diode are output ends of the access unit.

[0068] In an exemplary embodiment, the oscillation signal is a square wave signal.

[0069] In an exemplary embodiment, the inverting amplifier circuit may be any inverting amplifier circuit in the prior art.

[0070] The fault detection circuit of the embodiment of the present application can automatically detect whether the winding of the speed sensor is broken when the vehicle is stationary, thereby improving the safety of the vehicle.

[0071] Figure 2 is a schematic diagram of a fault detection method according to an embodiment of the present application, such as Figure 2 As shown, including steps S21-S22:

[0072] S21, obtaining an output signal of a fault detection circuit;

[0073] S22. Determine whether the winding of the speed sensor is broken according to the output signal.

[0074] In an exemplary embodiment, the fault detection circuit is the above-mentioned fault detection circuit;

[0075] In an exemplary embodiment, judging whether the winding is broken according to the output signal includes:

[0076] If the output signal is a square wave signal, it is determined that the winding is not broken.

[0077] In an exemplary embodiment, judging whether the winding is broken according to the output signal includes:

[0078] If the output signal is not a square wave signal, it is determined that the winding is broken.

[0079] In an exemplary embodiment, when a vehicle equipped with the speed sensor is in a driving state, the current driving speed of the vehicle can be calculated according to the square wave signal.

[0080] In an exemplary embodiment, the fault detection method of the present application is applied to an MCU (micro control unit) of a main control board of a vehicle equipped with a speed sensor.

[0081] The fault detection method of the embodiment of the present application can automatically detect whether the winding of the speed sensor is broken when the vehicle is stationary, thereby improving the safety of the vehicle.

[0082] Figure 3is a schematic diagram of a fault detection system according to an embodiment of the present application, such as Figure 3 As shown, the fault detection system of this embodiment includes a fault detection circuit and an MCU;

[0083] The fault detection circuit is the above-mentioned fault detection circuit;

[0084] The MCU is configured to obtain an output signal of the fault detection circuit, and determine whether the winding of the speed sensor is broken according to the output signal.

[0085] The MCU is a microcontroller unit of a main control board of a vehicle equipped with a speed sensor.

[0086] The fault detection system of the embodiment of the present application can automatically detect whether the winding of the speed sensor is broken when the vehicle is stationary, thereby improving the safety of the vehicle.

[0087] The fault detection circuit of the present application is described below using an oscillating waveform shaping circuit as a specific example.

[0088] Oscillating waveform shaping circuit (such as Figure 4 As shown in Figure 1), the winding of the speed sensor is connected to the oscillating waveform shaping circuit, and the output is a dynamic square wave. The circuit is divided into three levels. The first level is the access unit (as shown in Figure 1). Figure 5 As shown), the second stage is the oscillation unit (as Figure 6 As shown), the third stage is an inverting amplifier unit.

[0089] When the vehicle is at rest, the winding of the speed sensor is connected to the oscillating waveform shaping circuit in the form of a resistor.

[0090] When the vehicle is in a running state and the speed sensor is working normally, current flows through the winding of the speed sensor. At this time, the speed sensor is connected to the oscillating waveform shaping circuit in the form of a current source.

[0091] Among them, the working principle of the oscillation circuit is as follows:

[0092] (1) When one of TR1 and TR2 is turned on immediately after the power is turned on, the other is turned off. In this case, TR1 is turned on first.

[0093] (2) When TR1 is on and TR2 is off, the charging current of C1 is Figure 6 The solid arrow in the middle line flows in the direction of the charge. C1 is charged, causing the base voltage of TR2 to rise slowly.

[0094] (3) When the base voltage of TR2 exceeds the base voltage of TR1, TR2 is turned on and TR1 is turned off.

[0095] (4) As TR1 is disconnected, the collector voltage of TR1 rises linearly, and the base voltage of TR2 also rises linearly (thereby accelerating the connection action of TR2).

[0096] (5) When TR2 is turned on, the charge and discharge current of C1 will be Figure 6 The current flows in the direction of the dotted arrow, and the base voltage of TR2 decreases slowly.

[0097] (6) When the base voltage of TR2 is lower than the base voltage of TR1, TR2 is disconnected and TR1 is connected.

[0098] (7) As TR1 is turned on, the collector voltage of TR1 drops linearly, and the base voltage of TR2 also drops linearly (thereby accelerating the turning off action of TR2). Here, the state is the same as in (2) above.

[0099] (8) After that, by repeating the actions (2)-(7), the circuit is in an oscillation state.

[0100] (9) The charge and discharge current of C1 passes through R7 during both charging and discharging. Moreover, C2 is much higher than C1, so the charge and discharge current of C1 can be absorbed by the slight change of the charge of C2. Therefore, the oscillation frequency is roughly determined by the time constant of C1 and R7.

[0101] (10) When the winding of the speed sensor is broken, the base of TR1 will be pulled up to P15, TR1 will be always connected and TR2 will be always disconnected, and they cannot oscillate.

[0102] The present application describes multiple embodiments, but the description is exemplary rather than restrictive, and it is obvious to those skilled in the art that there may be more embodiments and implementations within the scope of the embodiments described in the present application. Although many possible feature combinations are shown in the drawings and discussed in the specific embodiments, many other combinations of the disclosed features are also possible. Unless specifically limited, any feature or element of any embodiment may be used in combination with any other feature or element in any other embodiment, or may replace any other feature or element in any other embodiment.

[0103] Any features shown and / or discussed in this application may be implemented alone or in any appropriate combination.

[0104] In addition, when describing representative embodiments, the specification may have presented the method and / or process as a specific sequence of steps. However, to the extent that the method or process does not rely on the specific order of steps described herein, the method or process should not be limited to the steps in the specific order described. As will be appreciated by those of ordinary skill in the art, other sequences of steps are also possible.

[0105] It will be appreciated by those skilled in the art that all or some of the steps, systems, and functional modules / units in the methods disclosed above may be implemented as software, firmware, hardware, and appropriate combinations thereof. In hardware implementations, the division between the functional modules / units mentioned in the above description does not necessarily correspond to the division of physical components; for example, a physical component may have multiple functions, or a function or step may be performed by several physical components in cooperation. Some or all components may be implemented as software executed by a processor, such as a digital signal processor or a microprocessor, or implemented as hardware, or implemented as an integrated circuit, such as an application-specific integrated circuit. Such software may be distributed on a computer-readable medium, which may include a computer storage medium (or non-transitory medium) and a communication medium (or temporary medium). As known to those skilled in the art, the term computer storage medium includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information (such as computer-readable instructions, data structures, program modules, or other data). Computer storage media include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tapes, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store the desired information and can be accessed by a computer. In addition, it is well known to those of ordinary skill in the art that communication media typically contain computer-readable instructions, data structures, program modules, or other data in a modulated data signal such as a carrier wave or other transport mechanism, and may include any information delivery media.

Claims

1. A fault detection circuit, applied to a speed sensor, characterized in that: The fault detection circuit comprises an access unit and an oscillation unit; The connecting unit is configured to connect the winding of the speed sensor to the oscillation unit; The oscillation unit is configured to generate or not generate an oscillation signal according to the state of the winding, so that whether the winding is broken is determined according to the presence or absence of the oscillation signal; The oscillation unit includes a first NPN transistor, a second NPN transistor, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, a first capacitor, a second capacitor, a first diode, a second diode and a DC power supply; The collector of the first NPN transistor is connected to the DC power supply through a fourth resistor; the base of the first NPN transistor is connected to the first end of the third resistor; the emitter of the first NPN transistor is connected to the anode of the first diode; The second end of the third resistor is connected to the first end of the first resistor and the first end of the second resistor respectively; the second end of the second resistor is connected to the DC power supply; the cathode of the first diode is connected to the first end of the sixth resistor; The collector of the second NPN transistor is connected to the DC power supply through the fifth resistor; the base of the second NPN transistor is connected to the first end of the seventh resistor; the emitter of the second NPN transistor is connected to the anode of the second diode; The second end of the third resistor is connected to the first end of the eighth resistor and the first end of the ninth resistor respectively; the second end of the eighth resistor is connected to the DC power supply; the cathode of the second diode is connected to the first end of the sixth resistor; The collector of the first NPN transistor and the base of the second NPN transistor are connected via the first capacitor; the second capacitor is connected in parallel with the ninth resistor; The second end of the sixth resistor is connected to the second end of the ninth resistor; The second end of the first resistor and the second end of the sixth resistor are input ends of the oscillation unit; the collector of the second NPN transistor and the second end of the ninth resistor are output ends of the oscillation unit; The access unit includes a tenth resistor, an eleventh resistor and a third diode; The tenth resistor is connected in series with the eleventh resistor; The tenth resistor and the eleventh resistor connected in series are connected in parallel with the third diode; the non-common end of the tenth resistor is connected to the anode of the third diode; The first end of the tenth resistor and the second end of the tenth resistor are input ends of the access unit; the anode and cathode of the third diode are output ends of the access unit.

2. The circuit according to claim 1, characterized in that The circuit also includes an inverting amplification unit; The inverting amplifier unit is configured to invert and amplify the oscillation signal and output the amplified signal.

3. The circuit according to claim 1, characterized in that The circuit also includes an optical coupling isolation unit; The optical coupling isolation unit is configured to isolate the circuit from other circuits.

4. A fault detection method, characterized in that: Acquire an output signal of a fault detection circuit; wherein the fault detection circuit is a circuit according to any one of claims 1 to 3; It is determined whether the winding of the speed sensor is broken according to the output signal.

5. The method according to claim 4, wherein judging whether the winding is broken according to the output signal comprises: If the output signal is a square wave signal, it is determined that the winding is not broken.

6. The method according to claim 4, wherein judging whether the winding is broken according to the output signal comprises: If the output signal is not a square wave signal, it is determined that the winding is broken.

7. The method of claim 5, further comprising: When the vehicle equipped with the speed sensor is in a driving state, the current driving speed of the vehicle is calculated according to the square wave signal.

8. A fault detection system, applied to a speed sensor, characterized in that: Including fault detection circuit and MCU; The fault detection circuit is a circuit as described in any one of claims 1 to 3; The MCU is configured to obtain an output signal of the fault detection circuit, and determine whether the winding of the speed sensor is broken according to the output signal.

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