Sensorless Magnetic Bearing Displacement Error Removal

The patent converts the harmful effect of exciting current variations (which cause inductance changes and detection errors) into a useful signal. By detecting the voltage waveform across the electromagnet and extracting the component corresponding to exciting current variations, the system uses this previously harmful signal as a reference to cancel out the detection error through subtraction, thereby improving displacement detection accuracy even at high frequencies

The system implements feedback by continuously monitoring the voltage waveform across the electromagnet, extracting the exciting current variation component, and using this information to compensate for displacement detection errors in real-time. This closed-loop approach allows the system to maintain accurate displacement detection while operating at high rotation speeds

The patent extracts only the necessary component (exciting current variation signal) from the voltage waveform through simple rectification and smoothing circuits, rather than using complex filtering systems. This extracted signal is then used for error compensation, achieving accurate displacement detection with minimal circuit complexity

The patent replaces complex mechanical or electronic filtering systems with a simpler signal processing approach based on waveform analysis and subtraction. Instead of using intricate filter networks to remove detection errors, the system uses digital or analog subtraction of the extracted exciting current component from the displacement signal, achieving the same goal with simpler hardware