A new energy vehicle disengagement mechanism control circuit with fault diagnosis function

Abstract

The present invention discloses a control circuit of a disengaging mechanism of a new energy vehicle with a fault diagnosis function, including a single-chip microcomputer MCU, a buffer Buffer, a field effect tube Q1, an AND gate U1, an op amp OPA, a comparator Comp1 and a comparator Comp2, wherein the sampling end of the single-chip microcomputer MCU is electrically connected to the output end of the op amp OPA, and a sampling resistor R1 is connected between the positive input end and the negative input end of the op amp OPA. Compared with the first scheme, the control circuit of a disengaging mechanism of a new energy vehicle with a fault diagnosis function disclosed by the present invention adds a fault diagnosis circuit, and when a fault occurs, the single-chip microcomputer can be used for fault detection and protection, and the fault status is recorded; compared with the second scheme, the electromagnetic valve control chip is not used, and only low-cost chips such as op amps, comparators, and AND gates are used to realize the control of the disengaging mechanism.

Description

Technical Field

[0001] The invention belongs to the technical field of control of a disengagement mechanism of a new energy vehicle, and in particular relates to a control circuit of a disengagement mechanism of a new energy vehicle with a fault diagnosis function. Background Art

[0002] The disengagement mechanism is used to open and close between the motor and the wheels of new energy hybrid vehicles. When the motor is needed to work, the disengagement mechanism is controlled to enter a closed state and connect to the wheels. When the motor is not needed to work, the disengagement mechanism is controlled to enter a disengaged state and disconnect from the wheels.

[0003] The actuator of the disengagement mechanism is an electromagnet. The disengagement mechanism control module is mounted in the motor controller. The PWM wave (proportional integral control) emitted by the single-chip microcomputer is used to adjust the current on the electromagnet to keep it in a constant current state, ensuring that the magnetic force is constant and can work normally. In the prior art:

[0004] For option 1, Figure 2 As shown, there is a disconnection mechanism between point A and point B. The MCU samples the current through the operational amplifier and sampling resistor, and then outputs the PWM wave through proportional integral control to control the opening and closing of the Mosfet to achieve constant current control. The control circuit does not add a fault diagnosis circuit. If point A or point B is short-circuited to the ground or short-circuited to the power supply, fault protection and fault status recording cannot be performed.

[0005] For option 2, Figure 3 As shown, the control circuit uses a solenoid valve control chip to control the disengagement mechanism. The MCU and the chip output instructions through communication, and the chip controls the disengagement mechanism according to the instructions. The chip has its own fault diagnosis and protection functions. However, the solenoid valve control chips on the current market have the characteristics of weak output load capacity or a large number of output channels (for example, the chip in the figure only uses 1 channel instead of 4 output channels), resulting in functional redundancy in the application of the disengagement mechanism and high prices.

[0006] Therefore, further improvements are made to the above problems. Summary of the invention

[0007] The main purpose of the present invention is to provide a new energy vehicle disengagement mechanism control circuit with a fault diagnosis function. Compared with Scheme 1, the present invention adds a fault diagnosis circuit. When a fault occurs, fault detection and protection can be performed through a single-chip microcomputer, and the fault status can be recorded; compared with Scheme 2, the solenoid valve control chip is not used, and only low-cost chips such as operational amplifiers, comparators, and AND gates are used to realize the control of the disengagement mechanism.

[0008] To achieve the above purpose, the present invention provides a new energy vehicle disengagement mechanism control circuit with a fault diagnosis function, including a single-chip microcomputer MCU, a buffer Buffer, a field effect transistor Q1, an AND gate U1, an operational amplifier OPA, a comparator Comp1 and a comparator Comp2, wherein:

[0009] The sampling end of the single-chip computer MCU is electrically connected to the output end of the operational amplifier OPA, a sampling resistor R1 is connected between the positive input end and the negative input end of the operational amplifier OPA, the positive input end of the operational amplifier OPA is connected to the power supply end VBAT through the disconnection mechanism U2 and the diode D1 in sequence, and the negative input end of the operational amplifier OPA is grounded through the field effect transistor Q1, the end of the disconnection mechanism U2 close to the CIA resistor R1 is set as point B, and the end of the disconnection mechanism U2 close to the diode D1 is set as point A;

[0010] The output end of the single-chip microcomputer MCU is electrically connected to the input end of the buffer Buffer, and the output end of the buffer Buffer is electrically connected to the gate of the field effect transistor Q1; the output end of the AND gate U1 is electrically connected to the enable end of the buffer Buffer through the diode D3;

[0011] The positive input terminal of the comparator Comp1 is connected to point B and the negative input terminal of the comparator Comp1 is connected to a first reference voltage (Ref1), one path of the output terminal (Out1) of the comparator Comp1 is electrically connected to the first input terminal of the single-chip microcomputer MCU and the other path is electrically connected to the first input terminal of the AND gate U1, and the second input terminal of the AND gate U1 is connected to the single-chip microcomputer MCU (MCU EN);

[0012] The positive input terminal of the comparator Comp2 is electrically connected to the output terminal of the operational amplifier OPA and the negative input terminal of the comparator Comp2 is connected to the second reference voltage (Ref2). The output terminal (Out2) of the comparator Comp2 is electrically connected to the second input terminal of the microcontroller MCU in one path and is electrically connected to the enable terminal of the buffer Buffer through the diode D4 in another path.

[0013] As a further preferred technical solution of the above technical solution, when the disengagement mechanism U2 is in a non-working state (MCU EN=0), wherein:

[0014] In normal state and fault state, the single-chip microcomputer MCU detects the short circuit to ground (STG) and the open circuit fault (OL) by detecting the level of the output terminal Out1 of the comparator Comp1 and the level of the output terminal Out2 of the comparator Comp2. At this time, if a fault is detected, the MCU EN signal of the single-chip microcomputer MCU keeps outputting at a low level to ensure that the disconnection mechanism U2 does not work; if no fault is detected, the MCU EN signal outputs a high level and sends a PWM switch signal to control the opening and closing of the field effect tube Q1, thereby controlling the operation of the disconnection mechanism U2.

[0015] As a further preferred technical solution of the above technical solution, when the disengagement mechanism U2 is in working state (MCUEN=1), wherein:

[0016] In the normal state and the fault state, the single-chip microcomputer MCU detects the level of the output terminal Out1 of the comparator Comp1, the level of the output terminal Out2 of the comparator Comp2 and the sampled current value (through the sampling resistor R1), and the single-chip microcomputer MCU first enables the MCU EN signal, and then sends out a PWM switch signal, and at the same time samples the current of the disconnection mechanism U2 in real time through the operational amplifier OPA and the sampling resistor R1, and the single-chip microcomputer MCU controls the field effect tube Q1 to switch according to the PWM wave sent by the MCU, so that the current is stabilized at the working current of the disconnection mechanism U2;

[0017] In order to detect faults in real time, the sampling signal ADC and the voltage at point B need to be compared with the reference threshold through a comparator. The detection logic is as follows: when a short power fault occurs at point B, Out1 or Out2 outputs a high level, and the buffer Buffer is immediately closed, and the field effect transistor Q1 is disconnected; when the second fault occurs (other faults in Table 2), since the ADC sampling current value is 0, which is different from the normal working current, the fault is distinguished.

[0018] As a further preferred technical solution of the above technical solution, a diode D2 is connected between point A and the negative input terminal of the operational amplifier OPA, and the output terminal and the negative input terminal of the operational amplifier OPA are connected.

[0019] As a further preferred technical solution of the above technical solution, the enable terminal of the buffer Buffer is also grounded through a resistor. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The invention discloses a control circuit diagram of a disengagement mechanism of a new energy vehicle with a fault diagnosis function.

[0021] Figure 2 It is the circuit diagram of the existing MCU controlled disengagement mechanism.

[0022] Figure 3 The invention is a circuit diagram of an existing electromagnetic valve chip controlled disengagement mechanism. DETAILED DESCRIPTION

[0023] The following description is used to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are only examples, and those skilled in the art can think of other obvious variations. The basic principles of the present invention defined in the following description can be applied to other embodiments, variations, improvements, equivalents, and other technical solutions that do not deviate from the spirit and scope of the present invention.

[0024] In the preferred embodiment of the present invention, those skilled in the art should note that the disengagement mechanism and the like involved in the present invention may be regarded as prior art.

[0025] Preferred embodiments.

[0026] The present invention discloses a new energy vehicle disengagement mechanism control circuit with a fault diagnosis function, comprising a single chip microcomputer MCU, a buffer Buffer, a field effect transistor Q1, an AND gate U1, an operational amplifier OPA, a comparator Comp1 and a comparator Comp2, wherein:

[0027] The sampling end of the single-chip computer MCU is electrically connected to the output end of the operational amplifier OPA, a sampling resistor R1 is connected between the positive input end and the negative input end of the operational amplifier OPA, the positive input end of the operational amplifier OPA is connected to the power supply end VBAT through the disconnection mechanism U2 and the diode D1 in sequence, and the negative input end of the operational amplifier OPA is grounded through the field effect transistor Q1, the end of the disconnection mechanism U2 close to the CIA resistor R1 is set as point B, and the end of the disconnection mechanism U2 close to the diode D1 is set as point A;

[0028] The output end of the single-chip microcomputer MCU is electrically connected to the input end of the buffer Buffer, and the output end of the buffer Buffer is electrically connected to the gate of the field effect transistor Q1; the output end of the AND gate U1 is electrically connected to the enable end of the buffer Buffer through the diode D3;

[0029] The positive input terminal of the comparator Comp1 is connected to point B and the negative input terminal of the comparator Comp1 is connected to a first reference voltage (Ref1), one path of the output terminal (Out1) of the comparator Comp1 is electrically connected to the first input terminal of the single-chip microcomputer MCU and the other path is electrically connected to the first input terminal of the AND gate U1, and the second input terminal of the AND gate U1 is connected to the single-chip microcomputer MCU (MCU EN);

[0030] The positive input terminal of the comparator Comp2 is electrically connected to the output terminal of the operational amplifier OPA and the negative input terminal of the comparator Comp2 is connected to the second reference voltage (Ref2). The output terminal (Out2) of the comparator Comp2 is electrically connected to the second input terminal of the microcontroller MCU in one path and is electrically connected to the enable terminal of the buffer Buffer through the diode D4 in another path.

[0031] Specifically, when the disengagement mechanism U2 is in a non-operating state (MCU EN=0), wherein:

[0032] In normal state and fault state, the single-chip microcomputer MCU detects the short circuit to ground (STG) and the open circuit fault (OL) by detecting the level of the output terminal Out1 of the comparator Comp1 and the level of the output terminal Out2 of the comparator Comp2. At this time, if a fault is detected, the MCU EN signal of the single-chip microcomputer MCU keeps outputting at a low level to ensure that the disconnection mechanism U2 does not work; if no fault is detected, the MCU EN signal outputs a high level and sends a PWM switch signal to control the opening and closing of the field effect tube Q1, thereby controlling the operation of the disconnection mechanism U2.

[0033] More specifically, when the disengagement mechanism U2 is in the working state (MCU EN=1), wherein:

[0034] In the normal state and the fault state, the single-chip microcomputer MCU detects the level of the output terminal Out1 of the comparator Comp1, the level of the output terminal Out2 of the comparator Comp2 and the sampled current value (through the sampling resistor R1), and the single-chip microcomputer MCU first enables the MCU EN signal, and then sends out a PWM switch signal, and at the same time samples the current of the disconnection mechanism U2 in real time through the operational amplifier OPA and the sampling resistor R1, and the single-chip microcomputer MCU controls the field effect tube Q1 to switch according to the PWM wave sent by the MCU, so that the current is stabilized at the working current of the disconnection mechanism U2;

[0035] In order to detect faults in real time, the sampling signal ADC and the voltage at point B need to be compared with the reference threshold through a comparator. The detection logic is as follows: when a short power fault occurs at point B, Out1 or Out2 outputs a high level, and the buffer Buffer is immediately closed, and the field effect transistor Q1 is disconnected; when the second fault occurs (other faults in Table 2), since the ADC sampling current value is 0, which is different from the normal working current, the fault is distinguished.

[0036] Furthermore, a diode D2 is connected between point A and the negative input terminal of the operational amplifier OPA, and the output terminal of the operational amplifier OPA is connected to the negative input terminal.

[0037] Furthermore, an enable terminal of the buffer Buffer is also grounded through a resistor.

[0038] For the present invention, the control circuit architecture of the disengagement mechanism described in the present invention is as follows Figure 1 As shown in the figure: MCU samples the current through the operational amplifier and sampling resistor, and then controls the output PWM wave through the proportional integral algorithm to control the opening and closing of the Mosfet (field effect tube Q1), thereby realizing constant current control of the disconnection mechanism. Fault detection and protection are then carried out through separate devices such as comparators, AND gates, and buffers.

[0039] A short-circuit power failure at point A or point B of the release mechanism may occur in its non-working state (MCU EN=0) or working state (MCU EN=1); if it occurs in the working state, it can be divided into two states: Q1 (MOSFET) is on or off.

[0040] As shown in Table 1, when the disconnect mechanism does not work, that is, MCU EN is at a low level, in normal and faulty states, the levels of OUT1 and OUT2 detected by the MCU port can detect short circuit to ground (STG) and open circuit fault (OL), but cannot detect short circuit to power supply fault (STP) at point A or point B. At this time, if a fault is detected, the MCU EN signal keeps outputting at a low level to ensure that the disconnect mechanism does not work; if no fault is detected, the MCU EN outputs a high level and sends out a PWM wave to control the disconnect mechanism to work.

[0041] Table 1 Fault status detection when the release mechanism is not working

[0042]

[0043] As shown in Table 2, when the disconnection mechanism is working, that is, when the MCU EN is at a high level, the OUT1 and OUT2 port levels detected by the MCU port and the current value sampled by the MCU are in normal and faulty states. The MCU first sends the MCU EN enable signal, and then sends the PWM switch signal. At the same time, the disconnection mechanism current is sampled in real time through the operational amplifier (OPA) and the sampling resistor. The MCU controls the MOS tube Q1 to switch according to the PWM wave sent by the MCU, so that the current is stable at the disconnection mechanism working current. In order to detect the fault in real time, the sampling signal (ADC) and the voltage at point B need to be compared with the reference threshold through the comparator. The detection logic is as follows: when a short power supply fault occurs at point B, OUT1 or OUT2 outputs a high level, and the buffer is immediately closed and the MOSFET is disconnected; when other faults in the table occur, it can be seen that the ADC sampling current value is 0, which is different from the normal working current, and the fault can be distinguished.

[0044] Table 2 Fault status detection when the disengagement mechanism is working

[0045]

[0046]

[0047] Note: STP = short circuit to power; STG = short circuit to ground; OL = open load; NOR = normal.

[0048] The beneficial effects of the present invention are:

[0049] 1. When a short-circuit or short-circuit power failure occurs in the release mechanism, the main fault detection and protection actions can be performed.

[0050] 2. The use of small-package, low-cost discrete device circuits to control the operation of the disengagement mechanism reduces material costs and reduces the area of ​​the circuit board occupied by the control circuit module.

[0051] It is worth mentioning that the technical features such as the disengagement mechanism involved in the patent application of this invention should be regarded as the prior art. The specific structure, working principle and possible control method and spatial layout method of these technical features can be selected by conventional methods in the field, and should not be regarded as the inventive point of the patent of this invention. The patent of this invention will not be further elaborated.

[0052] For those skilled in the art, it is still possible to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A new energy vehicle disengagement mechanism control circuit with a fault diagnosis function, characterized in that: It includes a single-chip microcomputer MCU, a buffer Buffer, a field effect transistor Q1, an AND gate U1, an operational amplifier OPA, a comparator Comp1 and a comparator Comp2, wherein: The sampling end of the single-chip computer MCU is electrically connected to the output end of the operational amplifier OPA, a sampling resistor R1 is connected between the positive input end and the negative input end of the operational amplifier OPA, the positive input end of the operational amplifier OPA is connected to the power supply end VBAT through the disconnection mechanism U2 and the diode D1 in sequence, and the negative input end of the operational amplifier OPA is grounded through the field effect transistor Q1, the end of the disconnection mechanism U2 close to the sampling resistor R1 is set as point B, and the end of the disconnection mechanism U2 close to the diode D1 is set as point A; The output end of the single-chip microcomputer MCU is electrically connected to the input end of the buffer Buffer, and the output end of the buffer Buffer is electrically connected to the gate of the field effect transistor Q1; the output end of the AND gate U1 is electrically connected to the enable end of the buffer Buffer through the diode D3; The positive input terminal of the comparator Comp1 is connected to point B and the negative input terminal of the comparator Comp1 is connected to a first reference voltage, one output terminal of the comparator Comp1 is electrically connected to the first input terminal of the single-chip microcomputer MCU and the other output terminal of the comparator Comp1 is electrically connected to the first input terminal of the AND gate U1, and the second input terminal of the AND gate U1 is connected to the single-chip microcomputer MCU; The positive input terminal of the comparator Comp2 is electrically connected to the output terminal of the operational amplifier OPA and the negative input terminal of the comparator Comp2 is connected to the second reference voltage. The output terminal of the comparator Comp2 is electrically connected to the second input terminal of the microcontroller MCU in one path and is electrically connected to the enable terminal of the buffer Buffer through the diode D4 in another path.

2. A new energy vehicle disengagement mechanism control circuit with a fault diagnosis function according to claim 1, characterized in that: When the disengagement mechanism U2 is in the non-working state, among which: In normal state and fault state, the single-chip microcomputer MCU detects short circuit to ground and open circuit faults by detecting the level of the output terminal Out1 of the comparator Comp1 and the level of the output terminal Out2 of the comparator Comp2. At this time, if a fault is detected, the MCU EN signal of the single-chip microcomputer MCU keeps outputting at a low level to ensure that the disconnection mechanism U2 does not work; if no fault is detected, the MCU EN signal outputs a high level and sends a PWM switch signal to control the opening and closing of the field effect tube Q1, thereby controlling the operation of the disconnection mechanism U2.

3. A new energy vehicle disengagement mechanism control circuit with a fault diagnosis function according to claim 2, characterized in that: When the disengagement mechanism U2 is in working state, among which: Under normal and fault conditions, the single-chip microcomputer MCU detects the level of the output terminal Out1 of the comparator Comp1, the level of the output terminal Out2 of the comparator Comp2, and the sampled current value. The single-chip microcomputer MCU first enables the MCU EN signal, and then sends out a PWM switch signal. At the same time, the current of the disconnection mechanism U2 is sampled in real time through the operational amplifier OPA and the sampling resistor R1. The single-chip microcomputer MCU controls the field effect tube Q1 to switch according to the PWM wave sent by the MCU, so that the current is stabilized at the working current of the disconnection mechanism U2; In order to detect faults in real time, the sampling signal ADC and the voltage at point B need to be compared with the reference threshold through a comparator. The detection logic is as follows: when a short power fault occurs at point B, Out1 or Out2 outputs a high level. At this time, the buffer Buffer is immediately closed and the field effect transistor Q1 is disconnected; when a second fault occurs, since the ADC sampling current value is 0, which is different from the normal working current, the fault can be distinguished.

4. A new energy vehicle disengagement mechanism control circuit with a fault diagnosis function according to claim 3, characterized in that: A diode D2 is connected between point A and the negative input terminal of the operational amplifier OPA, and the output terminal of the operational amplifier OPA is connected to the negative input terminal.

5. According to the new energy vehicle disengagement mechanism control circuit with fault diagnosis function as described in claim 4, the enable end of the buffer Buffer is also grounded through a resistor.

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