BEMF Reconstruction for Sinusoidal Motor Drive Synchronization

The patent applies preliminary action by measuring and storing the BEMF zero-crossing timing information in advance, then using this pre-acquired data to synchronize the drive signal without requiring tri-stating during operation. This allows the system to prepare synchronization data beforehand and apply it smoothly, avoiding the abrupt current transitions that cause acoustic noise.

The patent uses copying by creating a reconstructed BEMF signal from measured data and zero-crossing timing information, rather than directly using the physical BEMF signal obtained during tri-stating. This copy allows the system to maintain continuous drive voltage while still having access to synchronization information, avoiding the need to turn off the drive transistors and thereby maintaining stable phase current waveforms.

The patent replaces the complex mechanical/electronic system of tri-stating and DSP-based synchronization with a simplified electronic system using a state machine and basic arithmetic operations. Instead of using complex microcontrollers to manage tri-stating sequences and BEMF measurement, the invention substitutes these with a streamlined digital approach that uses simple timing measurements and calculations to achieve the same synchronization function with reduced complexity.