A stepper motor is an electro-mechanical device that converts an electrical pulse into a corresponding angular or linear displacement. It is also a type of drive device that can correspond to incremental output mechanical displacements and input digital pulses. A stepper motor has the ability to start and stop quickly. As long as the load of the motor does not exceed the dynamic torque it can provide, it can be controlled by the input pulse to start and stop it in a moment. Stepping motor step angle and speed are only related to the input pulse frequency, and have nothing to do with the ambient temperature, pressure, shock, vibration, nor affected by the fluctuation of the grid voltage and load changes, it has a fixed every rotation. The number of steps, step accuracy, and step error do not accumulate over a long period of time. Therefore, stepper motors are widely used in applications requiring precise positioning. In the control system, most of them adopt single-chip microcomputer control. Because the driving capability of the single-chip microcomputer is limited, the driver is required to drive the stepping motor. Drivers on the market today are basically developed for a certain type of motor, and the price is higher. Here we introduce a simple stepper motor drive circuit. 2 drive circuit schematic diagram gives one of the drive circuit, when the microcontroller output is low, VMOS IRF540 closed, the voltage difference between the two ends of the coil is 0, when the microcontroller output is high, VMOS open, the coil will Energize, produce magnetic pole, the rotor will turn to this energization coil. The A, B, C, D, and A phases of the stepper motor are alternately energized in cycles, and the rotor will rotate in the direction of ABCDA. This is called forward rotation of the stepper motor. When the power is turned into A, D, C, B, A, When the cycle is energized, the rotor will rotate in the direction of the ADCBA, which is called the reversal of the stepper motor. One phase winding L of the stepping motor is an inductive load. When the VMOS tube abruptly turns from saturated to cut off, the winding generates a large back electromotive force; this back electromotive force and the power supply u are superimposed on the collector of the VMOS tube. When it is on, it is easy to breakdown the power tube, and the freewheeling diode is connected in reverse between the collector of the power tube and the power source u, so that the back electromotive force generated by the motor winding at the moment of cutoff is dampened by the freewheeling effect of the diode. To protect the power tube from damage. Although the above circuit has a simple structure, in the high-frequency operating state, the efficiency is very poor, and the parallel capacitor C on the RC can improve the current pulse front of the stepping motor winding. When the power amplifier circuit input control signal to make the power tube turn on, the current flows through the capacitor through the winding, so there is a momentary impact current injected into the winding; so that the leading edge of injection current becomes significantly steeper, thus increasing the step Into the motor high frequency performance. Under the condition that the voltage u of the power amplifying circuit and the external resistor Rc do not change, the capacitor C is connected in parallel with Rc so that the average current value of the noting winding is relatively increased in one step cycle. This increases the torque of the stepper motor, especially when working in high frequencies. This kind of shunt capacitor single voltage power amplifier has more applications in practical applications. However, this kind of circuit also has its disadvantages. This means that when working at low frequencies, it will increase the shock and cause poor low-frequency performance. 3 interface software interface program: 4 stepping motor out of step problem Stepping motor out of step for two reasons. The first reason is that the acceleration of the rotor is slower than the rotating magnetic field of the stepper motor, that is, it is generated below the commutation speed. This is because the electric energy of the input motor is insufficient, and the synchronous torque generated in the stepping motor cannot make the rotor speed follow the rotating speed of the stator magnetic field, thereby causing loss of synchronization. And any frequency higher than this frequency will be out of sync. This out-of-step shows that the stepping motor's ability to pull is not enough. Once the load is reduced or the magnetizing current in the winding is increased, it is possible to overcome the out-of-step. The second reason is that the average speed of the rotor is higher than the average rotation speed of the stator magnetic field. At this time, the stator energizes the energizing time longer and is greater than the time required for the rotor step further, the rotor gains too much energy in the stepping process, thereby generating the oscillation oscillation of the preshoot and the backward stroke. When the oscillation is severe enough, it leads to out-of-step. Therefore, at the beginning of the stepping motor, the speed is low, and the second step starts the high-speed operation, which can avoid the loss of synchronization. Battery current. The temperature conditioning board selected Hongtuo PC6506G. The battery provides the SOC signal to the main controller. The use of the Hongtuo PC7483 board has four D/A channels. As the batteries studied so far are mainly colloidal sealed lead-acid batteries, their characteristics are relatively consistent, so we have only tested single cells. The detection system uses VB language to prepare battery data acquisition interface. The data acquisition interface can simultaneously collect the voltage sensor, temperature sensor and current sensor signal through 32 channels of the PC7422 board. Before the data mining, you must first set the sampling interval, and store the file path and file name, then press the start sampling button, the system will be collected at the set sampling interval. You can display the signal of each channel in real-time graphically by selecting the drop-down menu of the channel, or view its history curve by viewing the history curve button. The program is compiled into a time saving function, that is, when the timer reaches a certain time, the collected signal data is backed up, so as to prevent accidental mistakes and the program exits and loses data. (For example, a small current charging may take several hours for a complete test, Occasionally happens in such a long time). 4 Battery parameter SOC algorithm and its processing The battery parameter SOC value estimation algorithm has many kinds, if has uses the battery integration method to estimate the battery current SOC; Uses the battery fluid effective quality to estimate the battery SOC and so on. The battery SOC value used in this paper is estimated using the voltage and current of the battery at a certain time. According to the two-dimensional table of the remaining capacity SOC and the voltage and current determined by the battery test, the battery SOC is related to the voltage and current. Confirmation is the main purpose of this experiment. First of all, the battery capacity characteristics of the test, that is to do a few groups of constant current discharge test, the detection of constant discharge of the group can discharge the amount of electricity. During this capacity characteristic test, the voltage history at both ends of the battery is recorded at the same time. In this way, we convert the relationship between the current and the battery's remaining capacity based on the current history and the relationship between the capacity of the current history processing, ie, the abscissa is the remaining capacity of the battery, and the ordinate is the constant current of the battery (several groups). At the same time, the voltage history corresponding to each group of constant current tests is also converted into the relationship between the terminal voltage and the remaining battery capacity SOC. Then, the battery SOC is evenly divided evenly on the abscissa. For each SOC value, the y-coordinate parallel line and the terminal voltage curve intersect to form a set of points. This set of points is the battery discharge process (steady-state process) terminal voltage at the current SOC value. The relationship between current and current. In this way, the relationship between the terminal voltage and the current can be obtained for each set of battery SOCs, and the three can be combined to form a two-dimensional relationship table of the battery SOC and the terminal voltage and current. According to the hardware device provided by the battery testing system described above, the VB language is used for programming first to complete the data acquisition and data storage of the battery voltage, current, and temperature signals. In the processing of test data, g is analyzed and processed using the MATLAB language. 5 conclusions This article has combined the actual subject, introduced the important subsystem in the hybrid electric vehicle - the battery examination system composition and the parameter SOC algorithm application. A/D, D/A, and temperature conditioning boards provide hardware support for the acquisition of sensor input signals. And use computer VB programming technology, constitute the battery main test system, can complete the battery voltage, current and temperature acquisition and preservation. Then use the MATLAB language to process the data according to the described algorithm to obtain the required battery SOC parameters to meet the actual needs of the project. Moreover, the system is also open-ended, and can later provide hardware and software support for other types of battery characteristics research. (Continued from page 68) S Conclusion This article describes a simple stepper motor drive circuit, and a simple analysis of the problems that easily occur in the stepper motor. For those who do not require high motor speed, this circuit has obvious advantages. In the atmospheric sampler designed by the author, this circuit controlled stepper motor works well for the rotation of the needle valve. 360W Solar Panel,330 Watt Solar Panel,Solar Panel System,Anodized Aluminum Panels Zhejiang G&P New Energy Technology Co.,Ltd , https://www.solarpanelgp.com