A wireless current collection circuit for electric bicycle motor

Abstract

The invention discloses a wireless current collection circuit for an electric bicycle motor, belonging to the technical field of electric vehicles. The invention comprises a sampling resistor, a current limiting amplifier circuit, a filter circuit, a sampling MCU, a wireless transmission module, a wireless receiving module and a control MCU which are connected in series in a power supply circuit of a DC motor of the electric vehicle. The sampling signal of the sampling resistor is input to the input end of the current limiting amplifier circuit, the output end of the current limiting amplifier circuit is connected to the filter circuit, the output end of the filter circuit is connected to the AD input end of the sampling MCU, the sampling MCU communicates with the wireless transmission module through a serial port, the wireless transmission module communicates with the wireless receiving module through a wireless network, and the wireless receiving module is connected to the control MCU through a serial port, thus solving the technical problem of using a wireless data transmission network to collect the current of a rear wheel motor on a control panel. The invention saves the sampling signal line between the rear wheel motor and the control panel, reduces the cost and processing procedures, and avoids the problem of line wear during the movement of the electric vehicle.

Description

Technical Field

[0001] The invention belongs to the technical field of electric vehicles, and in particular relates to a wireless current collection circuit for an electric bicycle motor. Background Art

[0002] Electric vehicles are an indispensable means of transportation for domestic travel. Due to the shape of electric vehicles, the control circuit of the rear wheel motor needs to be connected to the control panel on the handlebars through a bus. The vibration generated by the electric vehicle during movement can easily shake the bus line apart, causing wear and affecting the normal operation of the electric vehicle.

[0003] Traditional electric vehicle control systems require a pair of signal lines to collect the current signal of the rear wheel motor to the control panel. Due to the long wiring, it is difficult to avoid interference problems. In addition, the wiring process is cumbersome and is easily worn during operation, affecting the control panel's monitoring of the motor current. Summary of the invention

[0004] The purpose of the present invention is to provide an electric bicycle motor current wireless acquisition circuit, which solves the technical problem of using a wireless data transmission network to collect the current of the rear wheel motor to a control panel.

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

[0006] A wireless current acquisition circuit for an electric bicycle motor comprises a sampling resistor, a current limiting amplifier circuit, a filter circuit, a sampling MCU, a wireless transmission module, a wireless receiving module and a control MCU which are connected in series in a power supply circuit of a DC motor of an electric bicycle. The sampling signal of the sampling resistor is input to the input end of the current limiting amplifier circuit, the output end of the current limiting amplifier circuit is connected to the filter circuit, the output end of the filter circuit is connected to the AD input end of the sampling MCU, the sampling MCU communicates with the wireless transmission module through a serial port, the wireless transmission module communicates with the wireless receiving module through a wireless network, and the wireless receiving module is connected to the control MCU through a serial port;

[0007] The sampling resistor includes a resistor R1, a resistor R2 and a resistor R3, which are connected in series in the DC motor power supply circuit of the electric vehicle, one end of the resistor R3 is connected to the ground wire, and the other end is a current sampling end;

[0008] The current limiting amplifier circuit includes an amplifier IC1, a resistor R7, a resistor R4, a resistor R10, a resistor R5, a potentiometer R6, a potentiometer R11, a diode D1, a transistor Q1, a transistor Q2, a resistor R9 and a resistor R13. The current sampling end is connected to the negative input end of the amplifier IC1 through the resistor R4, and the negative electrode of the amplifier IC1 is also connected to the middle contact of the potentiometer R6 through the resistor R7. One end of the potentiometer R6 is connected to a 15V power supply through the resistor R5, and the other end is connected to the ground wire. The positive input end of the amplifier IC1 is connected to the ground wire through the resistor R10. The negative input terminal of the amplifier IC1 is connected to one end of the potentiometer R11, the other end of the potentiometer R11 is connected to the emitter of the transistor Q2, the output terminal of the amplifier IC1 is connected to the anode of the diode D1, the cathode of the diode D1 is connected to the ground wire, the output terminal of the amplifier IC1 is also connected to the base of the transistor Q1, the relay of the transistor Q1 is connected to the 15V power supply through the resistor R9, the emitter of the transistor Q1 is connected to the base of the transistor Q2, the emitter of the transistor Q2 is connected to the 15V power supply through the resistor R9, and the emitter of the transistor Q2 is also connected to the ground wire through the resistor R13;

[0009] The filter circuit includes a resistor R15, a capacitor C1, an amplifier IC2, a resistor R16 and a capacitor C2, one end of the resistor R15 is connected to the emitter of the transistor Q2, and the other end is connected to the positive electrode of the capacitor C1, the positive electrode of the capacitor C1 is the current signal output end, the negative electrode of the capacitor C1 is connected to the negative input end of the amplifier IC2, the positive input end of the amplifier IC2 is connected to the ground wire, the output end of the amplifier IC2 is connected to the negative electrode of the capacitor C1 through the resistor R16, and the output end of the amplifier IC2 is also connected to the current signal output end shown through the capacitor C2;

[0010] The current signal output terminal is connected to the AD input terminal of the MCU.

[0011] Preferably, the 15V power supply is provided by a 15V three-terminal voltage regulator, the model of the 15V three-terminal voltage regulator is LM7815, and the input end of the 15V three-terminal voltage regulator is connected to the electric vehicle battery.

[0012] Preferably, the model of the amplifier IC1 is LM101; the model of the diode D1 is 1N5226; the resistance range of the resistor R9 is 0 to 1.3k ohms; the model of the amplifier IC2 is uA741; the model of the control MCU and the sampling MCU are both C8051F350; the model of the wireless sending module and the wireless receiving module are both HSD-61.

[0013] The electric bicycle motor current wireless acquisition circuit described in the present invention solves the technical problem of using a wireless data transmission network to collect the current of the rear wheel motor to the control panel. The present invention eliminates the sampling signal line between the rear wheel motor and the control panel, reduces the cost and processing steps, and avoids the problem of line wear during the movement of the electric vehicle; the present invention uses a current limiting amplifier circuit to convert the collected current into a voltage signal, and limits the output of the voltage signal to 3V, thereby eliminating the impact of the peak current on the subsequent sampling MCU when the motor starts, and ensuring the safety of the subsequent circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a system architecture diagram of the present invention;

[0015] Figure 2 It is a circuit diagram of the current limiting amplifier circuit and the filter circuit of the present invention. DETAILED DESCRIPTION

[0016] like Figure 1-Figure 2 The electric bicycle motor current wireless acquisition circuit shown includes a sampling resistor, a current limiting amplifier circuit, a filter circuit, a sampling MCU, a wireless transmission module, a wireless receiving module and a control MCU connected in series in the power supply circuit of the electric vehicle DC motor. The sampling signal of the sampling resistor is input to the input end of the current limiting amplifier circuit, the output end of the current limiting amplifier circuit is connected to the filter circuit, the output end of the filter circuit is connected to the AD input end of the sampling MCU, the sampling MCU communicates with the wireless transmission module through the serial port, the wireless transmission module communicates with the wireless receiving module through the wireless network, and the wireless receiving module is connected to the control MCU through the serial port;

[0017] The sampling resistor includes a resistor R1, a resistor R2 and a resistor R3, which are connected in series in the DC motor power supply circuit of the electric vehicle, one end of the resistor R3 is connected to the ground wire, and the other end is a current sampling end;

[0018] The current limiting amplifier circuit includes an amplifier IC1, a resistor R7, a resistor R4, a resistor R10, a resistor R5, a potentiometer R6, a potentiometer R11, a diode D1, a transistor Q1, a transistor Q2, a resistor R9 and a resistor R13. The current sampling end is connected to the negative input end of the amplifier IC1 through the resistor R4, and the negative electrode of the amplifier IC1 is also connected to the middle contact of the potentiometer R6 through the resistor R7. One end of the potentiometer R6 is connected to a 15V power supply through the resistor R5, and the other end is connected to the ground wire. The positive input end of the amplifier IC1 is connected to the ground wire through the resistor R10. The negative input terminal of the amplifier IC1 is connected to one end of the potentiometer R11, the other end of the potentiometer R11 is connected to the emitter of the transistor Q2, the output terminal of the amplifier IC1 is connected to the anode of the diode D1, the cathode of the diode D1 is connected to the ground wire, the output terminal of the amplifier IC1 is also connected to the base of the transistor Q1, the relay of the transistor Q1 is connected to the 15V power supply through the resistor R9, the emitter of the transistor Q1 is connected to the base of the transistor Q2, the emitter of the transistor Q2 is connected to the 15V power supply through the resistor R9, and the emitter of the transistor Q2 is also connected to the ground wire through the resistor R13;

[0019] The sampling resistor R3 divides the collected current signal into a voltage signal and sends it to the negative input terminal of the amplifier IC1. When the current is normal, the diode D1 is not conducting. At this time, the amplifier IC1, the transistor Q1 and the transistor Q2 form an inverted amplifier with a gain of 1, which amplifies the voltage signal and sends it to the filter circuit.

[0020] If the peak current at motor startup is too large, the maximum output current of amplifier IC1 is 25mA. When the maximum output voltage of the voltage signal reaches the stable voltage of diode D1, diode D1 is turned on. At this time, diode D1 clamps the output voltage of amplifier IC1 at about 3V, limiting the voltage value output to the filter circuit to 1.5 to 2.5V, protecting the subsequent circuit from the impact of peak current.

[0021] The filter circuit includes a resistor R15, a capacitor C1, an amplifier IC2, a resistor R16 and a capacitor C2, one end of the resistor R15 is connected to the emitter of the transistor Q2, and the other end is connected to the positive electrode of the capacitor C1, the positive electrode of the capacitor C1 is the current signal output end, the negative electrode of the capacitor C1 is connected to the negative input end of the amplifier IC2, the positive input end of the amplifier IC2 is connected to the ground wire, the output end of the amplifier IC2 is connected to the negative electrode of the capacitor C1 through the resistor R16, and the output end of the amplifier IC2 is also connected to the current signal output end through the capacitor C2;

[0022] The present invention adopts amplifier IC2 to form an active filter, which has a good filtering effect on the AC interference signal generated by the motor. C1 and C2 of the present invention both adopt low-leakage DC capacitors, and the input end of the amplifier is well isolated, thereby ensuring the accuracy of the signal.

[0023] The current signal output terminal is connected to the AD input terminal of the MCU.

[0024] Preferably, the 15V power supply is provided by a 15V three-terminal voltage regulator, the model of the 15V three-terminal voltage regulator is LM7815, and the input end of the 15V three-terminal voltage regulator is connected to the electric vehicle battery.

[0025] Preferably, the model of the amplifier IC1 is LM101; the model of the diode D1 is 1N5226; the resistance range of the resistor R9 is 0 to 1.3k ohms; the model of the amplifier IC2 is uA741; the model of the control MCU and the sampling MCU are both C8051F350; the model of the wireless sending module and the wireless receiving module are both HSD-61.

[0026] The present invention adopts C8051F350 as the controller, which has a 24-bit AD, thereby reducing the cost.

[0027] The control MCU is used to connect to the control panel of the electric bicycle.

[0028] The electric vehicle battery of the present invention adopts a 48V battery pack.

[0029] The electric bicycle motor current wireless acquisition circuit described in the present invention solves the technical problem of using a wireless data transmission network to acquire the current of the rear wheel motor to the control panel. The present invention eliminates the sampling signal line between the rear wheel motor and the control panel, reduces the cost and processing steps, and avoids the problem of line wear during the movement of the electric vehicle. The present invention uses a current limiting amplifier circuit to convert the acquired current into a voltage signal, and limits the output of the voltage signal to 3V, thereby eliminating the impact of the peak current on the subsequent sampling MCU when the motor starts, and ensuring the safety of the subsequent circuit.

Claims

1. A wireless current collection circuit for electric bicycle motors. Features: It includes a sampling resistor, a current limiting amplifier circuit, a filter circuit, a sampling MCU, a wireless transmission module, a wireless receiving module and a control MCU which are connected in series in the power supply circuit of the DC motor of the electric vehicle. The sampling signal of the sampling resistor is input to the input end of the current limiting amplifier circuit, the output end of the current limiting amplifier circuit is connected to the filter circuit, the output end of the filter circuit is connected to the AD input end of the sampling MCU, the sampling MCU communicates with the wireless transmission module through a serial port, the wireless transmission module communicates with the wireless receiving module through a wireless network, and the wireless receiving module is connected to the control MCU through a serial port; The sampling resistor includes a resistor R1, a resistor R2 and a resistor R3, which are connected in series in the DC motor power supply circuit of the electric vehicle, one end of the resistor R3 is connected to the ground wire, and the other end is a current sampling end; The current limiting amplifier circuit includes an amplifier IC1, a resistor R7, a resistor R4, a resistor R10, a resistor R5, a potentiometer R6, a potentiometer R11, a diode D1, a transistor Q1, a transistor Q2, a resistor R9 and a resistor R13. The current sampling end is connected to the negative input end of the amplifier IC1 through the resistor R4, and the negative electrode of the amplifier IC1 is also connected to the middle contact of the potentiometer R6 through the resistor R7. One end of the potentiometer R6 is connected to a 15V power supply through the resistor R5, and the other end is connected to the ground wire. The positive input end of the amplifier IC1 is connected to the ground wire through the resistor R10. The negative input terminal of the amplifier IC1 is connected to one end of the potentiometer R11, the other end of the potentiometer R11 is connected to the emitter of the transistor Q2, the output terminal of the amplifier IC1 is connected to the anode of the diode D1, the cathode of the diode D1 is connected to the ground wire, the output terminal of the amplifier IC1 is also connected to the base of the transistor Q1, the relay of the transistor Q1 is connected to the 15V power supply through the resistor R9, the emitter of the transistor Q1 is connected to the base of the transistor Q2, the emitter of the transistor Q2 is connected to the 15V power supply through the resistor R9, and the emitter of the transistor Q2 is also connected to the ground wire through the resistor R13; The filter circuit includes a resistor R15, a capacitor C1, an amplifier IC2, a resistor R16 and a capacitor C2, one end of the resistor R15 is connected to the emitter of the transistor Q2, and the other end is connected to the positive electrode of the capacitor C1, the positive electrode of the capacitor C1 is the current signal output end, the negative electrode of the capacitor C1 is connected to the negative input end of the amplifier IC2, the positive input end of the amplifier IC2 is connected to the ground wire, the output end of the amplifier IC2 is connected to the negative electrode of the capacitor C1 through the resistor R16, and the output end of the amplifier IC2 is also connected to the current signal output end through the capacitor C2; The current signal output terminal is connected to the AD input terminal of the MCU; The 15V power supply is provided by a 15V three-terminal voltage regulator, the model of the 15V three-terminal voltage regulator is LM7815, and the input end of the 15V three-terminal voltage regulator is connected to the electric vehicle battery; The model of the amplifier IC1 is LM101; the model of the diode D1 is 1N5226; the resistance range of the resistor R9 is 0 to 1.3k ohms; the model of the amplifier IC2 is uA741; the model of the control MCU and the sampling MCU are both C8051F350; the model of the wireless transmission module and the wireless receiving module are both HSD-61.

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