CN100391760C - Digital intelligent electric vehicle control method - Google Patents

Abstract

The invention relates to a digital intelligent electric vehicle control method and a controller. By acquiring the instantaneous speed signal and load signal directly detected by a sensor from any position in the middle of the electric bicycle transmission or at the terminal, through a single-chip microcomputer, a control selection switch, a comparator, and a PWM voltage regulation modulation Processors and other processing, accurately and timely deliver the required power to the motor, control the motor is always in an efficient working state, the battery is always in the best discharge state, prolong the service life of the battery, increase the continuation distance and climbing of the electric vehicle Ability to automatically eliminate unnecessary power loss caused by human misoperation, inaccurate control and other non-standard conditions, achieving the effect of high efficiency, energy saving and intelligent driving.

Description

Digital intelligent electric vehicle control method

technical field

The invention belongs to the technical field of electric vehicle control, and in particular relates to a control method and a controller of a digital intelligent electric vehicle.

Background technique

Existing electric vehicles, such as electric bicycles, all have a set of controllers that control the working conditions of the electric motors, and the controllers control the work of the electric motors according to the manual operation instructions of the rider. The basis for the cyclist to issue various instructions is the feeling and experience judgment of the riding situation, such as under light load, heavy load state, climbing and other driving states, because it is impossible for people to accurately feel the electric vehicle in various complex conditions. The speed and load changes under working conditions, let alone the most effective power that the motor needs to provide under these conditions cannot be accurately obtained. Therefore, this kind of artificial operation control is often inaccurate, sometimes even wrong, and will give the motor Unnecessary damage is caused, which is the main reason for the high repair rate of existing electric bicycle motors. At the same time, it also causes high current depth and excessive discharge of the battery, shortening the service life of the motor and battery. For example, when going uphill or headwind, people often hope Increase the input voltage without decreasing the speed, but because the current increases with the increase of the load when going uphill, it will exceed the rated power of the motor, causing the motor to stall and heat up or even burn out. In addition, continuous high-current discharge will also damage the lead-acid battery. Relatively large, resulting in a shortened service life.

Contents of the invention

The purpose of the present invention is to provide a digital intelligent electric vehicle control method and controller for the defects existing in the existing electric vehicle control, by obtaining the speed signal and the load signal directly detected by the sensor from the electric bicycle transmission terminal, the It is converted into a digital signal, processed, and the required power is delivered to the motor accurately and timely, so that the motor is always in an efficient working state, and the battery is always in the best discharge state, prolonging the service life of the battery and increasing the battery life of the electric vehicle. It can automatically eliminate unnecessary power loss caused by human misoperation, inaccurate control and other non-standard conditions, so as to achieve the effect of high efficiency, energy saving and intelligent driving.

The control method that the present invention adopts is as follows:

First, through the detection of a certain part or terminal in the transmission mechanism of the electric vehicle by the speed sensor and the load sensor, the vehicle operating condition information data such as the instantaneous speed signal and the load signal are obtained;

When the speed reaches the allowable starting speed, the microcontroller outputs a control signal to the PWM modulator to control the motor to start working;

At the same time, the handle speed regulation signal and load signal select the control mode through the control selection switch, and after the speed limit processing, input the PWM voltage regulation modulator to control the motor speed;

Among them, there are two states for the control selection: one is the manual speed control state, the rider can control the driving speed at will; the other is the intelligent control state, the driving speed is automatically controlled by the load curve model measured in advance, when the load sensor signal output is zero, adopt Manual speed control mode, when the signal output of the load sensor is not zero, turn on an electronic switch to shield the handle speed input, and intelligently control the driving speed first, using a single-chip microcomputer intelligent control speed mode.

In order to realize the above control method, the present invention designs a digital intelligent electric vehicle controller. It retains the handle speed regulating circuit, brake control circuit, single chip microcomputer, PWM voltage regulating modulator, battery and motor of the traditional electric vehicle controller, and adds speed sensor, load sensor, control selection switch and comparator. The output of the speed sensor is connected to the general-purpose I/O port of the single-chip microcomputer, and the general-purpose I/O port output of the single-chip microcomputer allows the starting motor signal and the speed limit signal, and allows the starting motor signal and the output signal of the brake control circuit to be connected to the PWM regulator. The inverting input of the error amplifier I. The output signal of the handle speed regulating circuit and the output of the load sensor are connected to the selection control switch. After the output is connected in parallel with the speed limit signal, it is processed by a comparator and then connected to the input terminal of the intermittent adjustment circuit of the PWM voltage regulating modulator. The output terminal of the PWM voltage regulating modulator is connected to a field effect tube, and the field effect tube is connected to a battery and a motor to form a closed loop. If the control selection switch is closed, the output of the load sensor is grounded, and the speed is controlled manually at this time; if the control selection switch is open, when the output of the load sensor is zero, the electronic switch with priority for intelligent control is disconnected, and the speed is controlled manually at this time mode, when the output of the load sensor is not zero, the electronic switch is turned on, and the speed control signal of the handle is grounded. At this time, the intelligent control takes priority, which is the intelligent control speed mode.

The advantage of the present invention is that a speed sensor and a load sensor are added to the original control circuit, through which the accurate and true rotational speed signal and load signal can be directly detected from any position in the transmission terminal or middle of the electric vehicle, and converted into a digital signal by the controller. The signal is processed, and the required power is delivered to the motor in an accurate and timely manner. Through pulse width modulation, the output power of the motor is controlled synchronously, so as to avoid the occurrence of overload operation and stalling of the motor under heavy load conditions such as uphill, and the motor is always controlled. Efficient working state, the battery is always in the best discharge state, prolongs the service life of the battery, increases the driving distance and climbing ability of the vehicle, and automatically eliminates unnecessary errors caused by human misoperation, inaccurate control and other non-standard states power loss. At the same time, by setting a selection control switch, the user can choose the automatic speed regulation of the system or the manual speed regulation through the handle governor, so that the system has two states of manual and automatic. Due to the increase of the control mode, an input selection control device, namely a comparator, is added to judge which one is the input of the automatic control system between the handle signal and the load sensor signal, and when the speed reaches 20 km/h, the speed will not increase, so The vehicle has three control functions and usage methods: human control, intelligent control, and intelligent compensation for human riding. Intelligent sensing and artificial speed regulation can be used alternately, which can increase the mileage by 40% compared with full electric bicycles, and is safer. Good, to achieve the effect of high efficiency, energy saving and intelligent drive.

Description of drawings

Fig. 1 is a general control circuit block diagram of the present invention;

Fig. 2 is a circuit diagram of the present invention.

Detailed ways

Referring to Fig. 1, this digital intelligent electric vehicle controller is used on an electric bicycle, and consists of a speed sensor, a load sensor, a handle speed regulating circuit, a brake control circuit, a single-chip microcomputer, a PWM modulator, an undervoltage protection circuit and an overcurrent protection circuit, Control selector switch, comparator, battery and motor. The output of the speed sensor is connected to the general-purpose I/O port of the single-chip microcomputer, and the general-purpose I/O port output of the single-chip computer allows the starting motor signal and the speed limit signal, and allows the starting motor signal and the brake control signal to be connected to the error amplifier I of the PWM regulator modulator. the inverting input terminal. After the speed control signal of the handle is connected in parallel with the output of the load sensor and the speed limit signal, it is processed by a comparator and then connected to the input terminal of the intermittent period adjustment circuit of the PWM voltage regulating modulator. The output terminal of the PWM voltage regulating modulator is connected to the field effect tube, and then connected to the motor through the battery. The under-voltage protection circuit and the over-current protection circuit protect the motor, and their outputs are connected in parallel to the non-inverting input terminal of the error amplifier II of the PWM modulator. The feedback potential detection signal of the motor is connected to the non-inverting input terminal of the error amplifier I of the PWM voltage regulating modulator. The speed function selection switch is connected to the output end of the load sensor, and the electronic switch for disconnecting the handle speed regulation is connected to the output end of the handle speed regulation when there is a load. The feedback potential detection signal of the motor is connected to the non-inverting input terminal of the error amplifier I of the PWM voltage regulating modulator. Motor undervoltage protection circuit and overcurrent protection circuit, their outputs are connected in parallel to the noninverting input terminal of the error amplifier II of the PWM modulator.

The PWM modulator in this controller adopts TL494, including a reference voltage generation circuit, an oscillation circuit, an intermittent adjustment circuit, two error amplifier circuits, a pulse width modulation comparator and an output circuit.

The working conditions of this controller are specifically described below in conjunction with Figure 2:

In this controller, the speed sensor and load sensor installed at the end of the transmission mechanism of the electric vehicle (such as the rear axle of a bicycle) input the real-time speed signal and load signal into the controller in the form of voltage. The speed sensor is a switch-type Hall sensor. Four pieces of magnetic steel are evenly pasted on the edge of the disk of non-magnetic material, and the disk is fixed on the measured rotating shaft, that is, the rear wheel shaft of the bicycle. The switch-type Hall sensor is fixed near the outer edge of the disk, and the Hall sensor outputs four pulses every time the disk rotates once, and the speed can be known by processing these pulses with a single-chip microcomputer. According to the actual situation, the allowable starting motor speed (5km/h) and the speed limit (20km/h) have been preset in the single-chip microcomputer. When the speed of the electric bicycle reaches five kilometers, the foot P3.4 of the single-chip microcomputer will record the speed. After the input pulse of the sensor reaches a certain number, the pin P1.7 outputs a high level, turns on the triode V1, and grounds the input of the inverting terminal of the error amplifier I of the PWM voltage regulator, so that the PWM voltage regulator can start Work. When the speed of the electric bicycle reaches 20 kilometers, the pin P1.6 of the single-chip microcomputer outputs a high level, turns on the triode V8, and releases part of the electric energy of the capacitor C17, thereby reducing the input of the PWM voltage regulator for intermittent regulation. Controlling the speed of the e-bike no longer increases. When the speed of the electric bicycle is less than 20 kilometers, the pin P1.6 outputs a low level, and the load (displacement) sensor and the handle governor charge the capacitor C17, so that the voltage of the capacitor rises, thereby increasing the voltage of the PWM regulator. The input of the intermittent adjustment makes the speed of the electric bicycle rise.

The load sensor uses a linear Hall sensor, which installs a magnetic ring on the edge of a disc of non-magnetic material or evenly distributes twelve pieces of magnetic steel (after rotating, it can be considered as a magnetic ring approximately), and fixes the disc on the on the measured shaft. The linear Hall sensor is fixed near the outer edge of the disc, and the S and N poles are respectively installed on both sides of the disc. When the distance between the Hall sensor and the magnetic steel is different, the S pole and the N pole change between 0-2.5V and 2.5-5V respectively. After the output signals of the S pole and the N pole are connected to the operational amplifier for comparison, a 0~5V signal, this signal is proportional to the load condition, input it to the control circuit, after the load sensor is compared with the handle speed regulation, the signal enters the input terminal of the PWM voltage regulator intermittent adjustment circuit, its When the voltage of 0-3.3V is applied, the cut-off time can be changed from 2% to 100%, so as to adjust the duty cycle of the output pulse. This pulse drives a field effect tube connected to the main circuit. Due to the field effect tube The change of the duty cycle of the drive pulse results in a different voltage applied to the motor, thereby controlling the motor speed.

The handle speed adjustment is the input end of the artificial control speed, and the load sensor is the input end of the automatic speed adjustment of the control system. When the selection control switch is closed, the manual speed control method is adopted to allow the rider to control the driving speed at will; when the control selection switch is open, considering the problems of limiting the motor power, preventing stalling and protecting the battery, the load sensor is used The way of intelligent control priority is to automatically control the driving speed according to the parameters determined in advance, and run at the highest possible speed under the premise of protecting the system. If the control selection switch is closed, the output of the load sensor is grounded. At this time, the input signal of the intelligent control is zero, and the system is in the mode of manual speed control; On, this is the manual speed control mode. When the output of the load sensor is not zero, turn on the electronic switch to ground the handle speed control signal. At this time, it is the intelligent control speed mode. When the load sensor detects that the load of the electric bicycle exceeds a certain value, The operational amplifier N4B outputs a high level to turn on the triode V3, so that the input terminal of the handle governor is grounded, thereby shielding the manual speed input, and the PWM voltage regulation and speed regulation system works according to the input of the load sensor to avoid heavy load conditions such as uphill The occurrence of motor overload operation and stalling.

The access of the brake signal is to control the power of the motor. When the rider squeezes the brake, the Hall sensor installed on the brake outputs a control signal to the PWM modulator to disconnect the power of the motor.

Since the power supply of the electric bicycle is a DC battery, in order to increase the life of the battery, the control system has added an overcurrent protection circuit and an undervoltage protection circuit. During the operation of the motor, these two modules monitor the main circuit voltage and current in real time. When the voltage When it is lower than 31.5V or the current is greater than 14A, the two modules output control signals to turn off the PWM modulator. BTR is the voltage input terminal of the DC battery. As the battery voltage decreases during use, the output of the operational amplifier N3B increases accordingly. R43 is a sampling resistor for overcurrent protection. When the load of the motor increases, the current increases and the voltage across R43 also increases. The undervoltage protection and overcurrent protection are connected in parallel as the positive phase input of the error amplifier II of the PWM voltage regulator. When the voltage is too low or the current is too large, the PWM voltage regulator is turned off to protect the motor. the goal of.

The feedback potential detection signal of the motor is connected to the non-inverting input terminal of the error amplifier I of the PWM voltage regulating modulator, and the non-inverting input terminal of the error amplifier I of the PWM voltage regulating modulator is connected to an analog voltage with an electronic switch, and the error amplifier I acts as The input of the pulse width modulation comparator, when the motor speed is low, that is, the feedback potential detection signal is lower than the analog voltage, use the analog input as the pulse width modulation comparator input, when the motor speed is high, that is, the feedback potential detection signal is higher than the analog voltage, Use the feedback potential detection signal as the input of the pulse width modulation comparator. The purpose of doing this is to control the voltage applied to both ends of the motor not to be too high at low speed, so that the starting current is small.

Claims (1)

1. A digital intelligent electric vehicle control method, characterized in that: First, the instantaneous speed signal and load signal of the vehicle running are obtained by detecting a certain part or terminal of the electric vehicle transmission mechanism through the speed sensor and the load sensor; When the speed reaches the allowable starting speed, the microcontroller outputs a control signal to the PWM modulator to control the motor to start working; At the same time, the handle speed regulation signal and load signal select the control mode through the control selection switch, and after the speed limit processing, input the PWM voltage regulation modulator to control the motor speed; Among them, there are two control methods: one is the manual speed control method, the rider can control the driving speed at will; the other is the intelligent control method, the driving speed is automatically controlled by the load curve model measured in advance, when the load sensor signal output is zero, adopt Manual speed control mode, when the signal output of the load sensor is not zero, turn on an electronic switch to shield the handle speed input, and intelligently control the driving speed first, using a single-chip microcomputer intelligent control speed mode.

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