A fault self-checking circuit for electric bicycle

Abstract

The invention discloses an electric bicycle fault self-checking circuit, which belongs to the technical field of electric vehicles, and comprises a power supply unit, an electric vehicle motor power supply circuit, a battery pack, a motor current sampling resistor R17, a Hall current sensor L3, a peak sampling and holding circuit, an undervoltage detection circuit, an amplifier circuit and an MCU controller U1; the technical problem of collecting the peak current of the motor through the sampling and holding circuit is solved, the invention adopts a Hall sensor to collect the working current of the motor, and amplifies its current signal through an adjustable gain amplifier circuit, so that the amplification gain can be well controlled during production, and the number of defective products in production is reduced; the invention can directly measure the peak current of the motor, and prevent the motor from being damaged due to excessive peak current.

Description

Technical Field

[0001] The invention belongs to the technical field of electric vehicles, and in particular relates to a fault self-detection circuit for an electric bicycle. Background Art

[0002] With the development of social economy, people have more and more demands for the intelligence of electric vehicles. The existing electric vehicle control system has limited monitoring and control functions and low intelligence level, which makes it difficult to meet people's needs.

[0003] The traditional fault self-detection circuit intelligently detects the working current of the electric vehicle and the working voltage of the battery, and has a small detection area and a relatively single function. It cannot determine the peak current of the motor and its working status, and cannot effectively detect and prevent motor faults. Summary of the invention

[0004] The purpose of the present invention is to provide a fault self-checking circuit for an electric bicycle, which solves the technical problem of collecting the peak current of a motor through a sampling and holding circuit.

[0005] To achieve the above object, the present invention adopts the following technical solution:

[0006] An electric bicycle fault self-checking circuit includes a power supply unit, an electric vehicle motor power supply circuit, a battery pack, a motor current sampling resistor R17, a Hall current sensor L3, a peak sampling and holding circuit, an undervoltage detection circuit, an amplifier circuit and an MCU controller U1;

[0007] The positive electrode of the battery pack B1 provides BAT voltage, and the negative electrode provides ground. The battery pack supplies power to the DC circuit of the electric vehicle. The positive electrode of the battery pack B1 supplies power to the power unit, and the power unit outputs +12V voltage, +5V voltage and -12V voltage.

[0008] The motor current sampling resistor R17 is connected in series in the electric vehicle motor power supply circuit, and the electric vehicle motor power supply circuit is also provided with a Hall current sensor L3;

[0009] The power supply end of the Hall current sensor L3 is connected to a 5V voltage, and the output end is connected to an amplifier circuit;

[0010] The amplifier circuit includes a resistor R8, a resistor R9, a resistor R10, a potentiometer R11 and an amplifier IC2. The resistor R8, the resistor R9, the resistor R10, the potentiometer R11 and the amplifier IC2 constitute a variable gain amplifier circuit. The output end of the Hall current sensor L3 is connected to the negative input end and the positive input end of the amplifier IC2 through the resistor R8 and the resistor R9 respectively. The output end of the amplifier IC2 is connected to the first AD port of the MCU controller U1. The potentiometer R10 is a gain adjustment resistor of the variable gain amplifier circuit.

[0011] The peak sampling and holding circuit includes a resistor R3, a resistor R1, a resistor R2, a potentiometer R4, an amplifier IC1, a diode D1, a resistor R5, a capacitor C1, a resistor R6, a capacitor C3, a field effect transistor Q1 and a resistor R7. One end of the resistor R3 is connected to the sampling end of the motor current sampling resistor R17, and the other end is connected to the negative input end of the amplifier IC1. The positive input end of the amplifier IC1 is connected to the ground wire through the resistor R1. The positive input end of the amplifier IC1 is also connected to the middle contact of the potentiometer R4 through the resistor R2. One end of the potentiometer R4 is connected to a 12V voltage, and the other end is connected to a -12V voltage.

[0012] The negative input terminal of the amplifier IC1 is also connected to the S pole of the field effect tube Q1 through the resistor R5, the capacitor is connected in parallel to the resistor R5, the output terminal of the amplifier IC1 is connected to the negative pole of the diode D1, the positive pole of the diode D1 is connected to one end of the switch S1 through the resistor R6, the other end of the switch S1 is connected to the 12V voltage, the positive pole of the diode D1 is also connected to the G pole of the field effect tube Q1, the D pole of the field effect tube Q1 is connected to the 12V voltage, the S pole is connected to the -12V voltage through the resistor R7, and the S pole of the field effect tube Q1 is connected to the second AD port of the MCU controller U1;

[0013] The undervoltage detection circuit includes a resistor R12, a resistor R14, a resistor R13, a resistor R15 and a comparator IC3. One end of the resistor R14 is connected to the BAT voltage and the other end is connected to the ground through the resistor R12. One end of R15 is connected to the 5V voltage and the other end is connected to the ground through the resistor R13. The connection node between the resistor R14 and the resistor R12 is also connected to the positive input end of the comparator IC3. The connection node between the resistor R13 and the resistor R15 is also connected to the negative input end of the comparator IC3. The output end of the comparator IC3 is connected to an IO port of the MCU controller U1.

[0014] Preferably, the model of the MCU controller is c8051f020; the model of the amplifier IC1 is CA3080, the model of the comparator IC3 is LM211; and the model of the amplifier IC2 is uA741.

[0015] Preferably, the power supply unit includes a 12VDC-DC module, a -12V three-terminal voltage regulator and a 5V three-terminal voltage regulator, the model of the -12V three-terminal voltage regulator is LM7912; the model of the 5V three-terminal voltage regulator is LM7805.

[0016] The electric bicycle fault self-checking circuit described in the present invention solves the technical problem of collecting the peak current of the motor through a sampling and holding circuit. The present invention adopts a Hall sensor to collect the working current of the motor and amplifies its current signal through an adjustable gain amplifier circuit, which can well control the amplification gain during production and reduce the number of defective products in production; the present invention can directly measure the peak current of the motor to prevent the motor from being damaged due to excessive peak current. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a system architecture diagram of the present invention. DETAILED DESCRIPTION

[0018] like Figure 1 The electric bicycle fault self-check circuit shown includes a power supply unit, an electric vehicle motor power supply circuit, a battery pack, a motor current sampling resistor R17, a Hall current sensor L3, a peak sampling and holding circuit, an undervoltage detection circuit, an amplifier circuit and an MCU controller U1;

[0019] The positive electrode of the battery pack B1 provides BAT voltage, and the negative electrode provides ground. The battery pack supplies power to the DC circuit of the electric vehicle. The positive electrode of the battery pack B1 supplies power to the power unit, and the power unit outputs +12V voltage, +5V voltage and -12V voltage.

[0020] The motor current sampling resistor R17 is connected in series in the electric vehicle motor power supply circuit, and the electric vehicle motor power supply circuit is also provided with a Hall current sensor L3;

[0021] The power supply end of the Hall current sensor L3 is connected to a 5V voltage, and the output end is connected to an amplifier circuit;

[0022] The amplifier circuit includes a resistor R8, a resistor R9, a resistor R10, a potentiometer R11 and an amplifier IC2. The resistor R8, the resistor R9, the resistor R10, the potentiometer R11 and the amplifier IC2 constitute a variable gain amplifier circuit. The output end of the Hall current sensor L3 is connected to the negative input end and the positive input end of the amplifier IC2 through the resistor R8 and the resistor R9 respectively. The output end of the amplifier IC2 is connected to the first AD port of the MCU controller U1. The potentiometer R10 is a gain adjustment resistor of the variable gain amplifier circuit.

[0023] The present invention adopts the Hall DC sensor L3 as a device for collecting the working current of the motor, which has high precision and stable performance. The model of the Hall DC sensor L3 is the HBA-NP Hall current sensor. The present invention adopts an amplifier circuit to amplify the signal of the Hall DC sensor L3 in the later stage. The amplifier circuit is a variable gain amplifier circuit. During production, the gain of the amplifier can be adjusted by adjusting the potentiometer R10. The operation is simple and convenient for proofreading during production.

[0024] The peak sampling and holding circuit includes a resistor R3, a resistor R1, a resistor R2, a potentiometer R4, an amplifier IC1, a diode D1, a resistor R5, a capacitor C1, a resistor R6, a capacitor C3, a field effect transistor Q1 and a resistor R7. One end of the resistor R3 is connected to the sampling end of the motor current sampling resistor R17, and the other end is connected to the negative input end of the amplifier IC1. The positive input end of the amplifier IC1 is connected to the ground wire through the resistor R1. The positive input end of the amplifier IC1 is also connected to the middle contact of the potentiometer R4 through the resistor R2. One end of the potentiometer R4 is connected to a 12V voltage, and the other end is connected to a -12V voltage.

[0025] The negative input terminal of the amplifier IC1 is also connected to the S pole of the field effect tube Q1 through the resistor R5, the capacitor is connected in parallel to the resistor R5, the output terminal of the amplifier IC1 is connected to the negative pole of the diode D1, the positive pole of the diode D1 is connected to one end of the switch S1 through the resistor R6, the other end of the switch S1 is connected to the 12V voltage, the positive pole of the diode D1 is also connected to the G pole of the field effect tube Q1, the D pole of the field effect tube Q1 is connected to the 12V voltage, the S pole is connected to the -12V voltage through the resistor R7, and the S pole of the field effect tube Q1 is connected to the second AD port of the MCU controller U1;

[0026] The peak sampling and holding circuit of the present invention uses an operational amplifier IC1 and a field effect transistor Q1 to form a peak detector, which can effectively improve the accuracy of the output peak value. The peak current of the motor can be intuitively obtained by collecting the voltage divider value on the resistor R17, and after passing through the peak sampling and holding circuit, the peak value of the input signal can be stored on the capacitor C3 for a long time, thereby enabling the MCU controller U1 to accurately obtain the peak current signal.

[0027] The undervoltage detection circuit includes a resistor R12, a resistor R14, a resistor R13, a resistor R15 and a comparator IC3. One end of the resistor R14 is connected to the BAT voltage and the other end is connected to the ground through the resistor R12. One end of R15 is connected to the 5V voltage and the other end is connected to the ground through the resistor R13. The connection node between the resistor R14 and the resistor R12 is also connected to the positive input end of the comparator IC3. The connection node between the resistor R13 and the resistor R15 is also connected to the negative input end of the comparator IC3. The output end of the comparator IC3 is connected to an IO port of the MCU controller U1.

[0028] The present invention adopts a comparator as the core element of the undervoltage detection circuit. When the battery voltage value decreases, the voltage division between the resistor R12 and the resistor R14 decreases accordingly. When it decreases to be less than the voltage division between the resistor R13 and the resistor R15, the comparator IC3 sends a low level alarm to the MCU controller U1.

[0029] Preferably, the model of the MCU controller is c8051f020; the model of the amplifier IC1 is CA3080, the model of the comparator IC3 is LM211; and the model of the amplifier IC2 is uA741.

[0030] Preferably, the power supply unit includes a 12VDC-DC module, a -12V three-terminal voltage regulator and a 5V three-terminal voltage regulator, the model of the -12V three-terminal voltage regulator is LM7912; the model of the 5V three-terminal voltage regulator is LM7805.

[0031] The present invention can pre-judge the health status of the motor by collecting the peak current of the motor to prevent further damage to the motor. The present invention monitors the working current of the motor in real time through the Hall DC sensor L3 and monitors the working status of the motor in real time.

[0032] The MCU controller U1 of this embodiment can be connected to an external display screen to display important parameters such as whether the motor peak current is normal, whether the motor operating current is normal, and whether the battery power is too low, so as to provide an intuitive display for the self-check of the electric bicycle.

[0033] The electric bicycle fault self-checking circuit described in the present invention solves the technical problem of collecting the peak current of the motor through a sampling and holding circuit. The present invention adopts a Hall sensor to collect the working current of the motor and amplifies its current signal through an adjustable gain amplifier circuit, which can well control the amplification gain during production and reduce the number of defective products in production; the present invention can directly measure the peak current of the motor to prevent the motor from being damaged due to excessive peak current.

Claims

1. An electric bicycle fault self-detection circuit, characterized in that: It includes a power supply unit, an electric vehicle motor power supply circuit, a battery pack, a motor current sampling resistor R17, a Hall current sensor L3, a peak sampling and holding circuit, an undervoltage detection circuit, an amplifier circuit and an MCU controller U1; The positive electrode of the battery pack B1 provides BAT voltage, and the negative electrode provides ground. The battery pack supplies power to the DC circuit of the electric vehicle. The positive electrode of the battery pack B1 supplies power to the power unit, and the power unit outputs +12V voltage, +5V voltage and -12V voltage. The motor current sampling resistor R17 is connected in series in the electric vehicle motor power supply circuit, and the electric vehicle motor power supply circuit is also provided with a Hall current sensor L3; The power supply end of the Hall current sensor L3 is connected to a 5V voltage, and the output end is connected to an amplifier circuit; The amplifier circuit includes a resistor R8, a resistor R9, a resistor R10, a potentiometer R11 and an amplifier IC2. The resistor R8, the resistor R9, the resistor R10, the potentiometer R11 and the amplifier IC2 constitute a variable gain amplifier circuit. The output end of the Hall current sensor L3 is connected to the negative input end and the positive input end of the amplifier IC2 through the resistor R8 and the resistor R9 respectively. The output end of the amplifier IC2 is connected to the first AD port of the MCU controller U1. The potentiometer R10 is a gain adjustment resistor of the variable gain amplifier circuit. The peak sampling and holding circuit includes a resistor R3, a resistor R1, a resistor R2, a potentiometer R4, an amplifier IC1, a diode D1, a resistor R5, a capacitor C1, a resistor R6, a capacitor C3, a field effect transistor Q1 and a resistor R7. One end of the resistor R3 is connected to the sampling end of the motor current sampling resistor R17, and the other end is connected to the negative input end of the amplifier IC1. The positive input end of the amplifier IC1 is connected to the ground wire through the resistor R1. The positive input end of the amplifier IC1 is also connected to the middle contact of the potentiometer R4 through the resistor R2. One end of the potentiometer R4 is connected to a 12V voltage, and the other end is connected to a -12V voltage. The negative input terminal of the amplifier IC1 is also connected to the S pole of the field effect tube Q1 through the resistor R5, the capacitor is connected in parallel to the resistor R5, the output terminal of the amplifier IC1 is connected to the negative pole of the diode D1, the positive pole of the diode D1 is connected to one end of the switch S1 through the resistor R6, the other end of the switch S1 is connected to the 12V voltage, the positive pole of the diode D1 is also connected to the G pole of the field effect tube Q1, the D pole of the field effect tube Q1 is connected to the 12V voltage, the S pole is connected to the -12V voltage through the resistor R7, and the S pole of the field effect tube Q1 is connected to the second AD port of the MCU controller U1; The undervoltage detection circuit includes a resistor R12, a resistor R14, a resistor R13, a resistor R15 and a comparator IC3, one end of the resistor R14 is connected to the BAT voltage, and the other end is connected to the ground through the resistor R12, one end of R15 is connected to the 5V voltage, and the other end is connected to the ground through the resistor R13, the connection node of the resistor R14 and the resistor R12 is also connected to the positive input end of the comparator IC3, the connection node of the resistor R13 and the resistor R15 is also connected to the negative input end of the comparator IC3, and the output end of the comparator IC3 is connected to an IO port of the MCU controller U1; The model of the MCU controller is c8051f020; the model of the amplifier IC1 is CA3080, the model of the comparator IC3 is LM211; the model of the amplifier IC2 is uA741; The power supply unit includes a 12VDC-DC module, a -12V three-terminal voltage regulator and a 5V three-terminal voltage regulator. The model of the -12V three-terminal voltage regulator is LM7912; the model of the 5V three-terminal voltage regulator is LM7805.

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