Application Cases

Experiment Name: Application of Power Amplifier in Inductive Sensor-Based Metal Particle Material Identification and Particle Size Estimation

Experiment Objective: A dual-phase-locked amplifier circuit is employed to convert the complex-domain signal generated by particles into a pair of DC signals. A signal processing method based on a fuzzy membership function is proposed to achieve material identification and particle size estimation for various particles under noise interference.

Experimental Equipment: Signal generator, ATA-3090 power amplifier, current probe, data acquisition card, three-coil inductive sensor, etc.

Experimental Procedure:

(1) Construction of the experimental setup;

(2) Detection experiment of complex-domain signals from metal particles;

Spherical particles made of five different materials were selected as test particles:

The three-coil sensor was placed inside a metal shield to block external electromagnetic interference. A sinusoidal voltage output from the signal generator served as the excitation voltage. The power amplifier parameters were set to a gain of 10×. The excitation current was monitored using a current probe, and a series ceramic capacitor was selected to achieve a resonant impedance close to purely resistive at the input end. Under this condition, the sensor could receive the maximum excitation current, allowing the field coil to generate the strongest alternating magnetic field. The signal generated by the sensing coil in the alternating magnetic field was transmitted to the dual-phase-locked amplifier circuit via an SMA connector.

Experimental Results:

Data acquisition from two channels with and without particle passage

Test particle 1 is highly likely to be a red copper particle with a particle size of approximately 180 μm, and is almost certainly not an aluminum particle or other type. Test particle 2 is basically determined to be an iron particle with a particle size of approximately 89 μm; it could potentially be a 403 steel particle with a particle size of approximately 1184 μm, but is highly unlikely to be any other type. This conclusion is essentially consistent with the actual properties of the particles, with a particle size estimation error of less than 2%. This demonstrates the effectiveness of the method for material identification and particle size estimation of various unknown particles.

Figure: ATA-3090C Power Amplifier Specifications and Parameters