[Zhengzhou Technology and Business College] Simple electronic load + Xiao Gu is right

Simple electronic load

This work mainly consists of the following parts:

Main control:

The main control uses the domestic CH32F03C8T6, which mainly collects the input current and voltage. And the voltage, current, and set current data are displayed in real time through OLED, and the power of the load is controlled through PWM.

Current collection:

The INA219 current acquisition module is used, which has the advantages of high accuracy and low drift. And uses the IIC protocol to communicate with the main control chip.

Voltage collection:

Use low-temperature 27K and 3K resistors to divide the input voltage, and then convert the input voltage through the ADC function of the main control chip.

Load circuit:

Using high-power transistor TIP41CA, the rated power of this transistor can reach 65W.

Display circuit:

The commonly used OLED screen is used to display information.

Use algorithm:

The current is collected through the current acquisition module, and the current through the load is also related to the voltage across the load. The duty cycle of PWM is not proportional to the load. So we introduced the PID control algorithm

Precise control of current.

data visualization:

Through the serial port, you can observe the changes in data through the computer host computer and easily adjust the PID parameter information. The interface is as follows

Red is the set current value and green is the actual current value. It can be seen that the response is very good.