2018 Electronic Competition Question A-Current Signal Detection Device (Dalian University of Technology)

The current signal detection device is a device that uses the principle of electromagnetic induction to convert a large current signal into a small current signal, and then analyzes it to obtain the amplitude and frequency of the original current signal. This system uses a microcontroller based on the CORTEX-M7 core to complete the control, mainly including the main control board module, power amplifier module, current transformer, precision amplifier circuit module, AD acquisition module and LCD display module. After the signal generated by the arbitrary waveform generator is driven by the power amplifier circuit, a 10 ohm load is connected to form a loop current. A self-made current transformer is used to induce the loop current signal to the secondary side, and the secondary side current signal is converted into a voltage signal. And amplify, then perform AD acquisition, use FFT transformation to perform frequency domain analysis, obtain the amplitude and frequency of the current signal, and display it through the LCD screen. Among them, the power amplification part uses TI's LM3886 68W audio power amplifier, and the current detection signal uses the OPA2191 operational amplifier for signal conditioning.