Brushless Motor Current Sensing Without Clarke Transform Noise

The patent divides the current sensing function into two separate sensors instead of using a single sensor, allowing independent measurement of two phase currents. This segmentation enables direct calculation of torque-producing current without the need for Clarke transform, eliminating the computational steps that cause audible noise while maintaining low device complexity.

The patent replaces the computational Clarke transform mechanism with a direct mathematical calculation using two sensor measurements. By measuring two phase currents directly and calculating the torque-producing current through simple algebraic operations, the system eliminates the complex transform calculations that generate audible noise, substituting a simpler computational approach.

The patent extracts only the essential measurement information needed for torque control by using two sensors to directly measure the phase currents that produce torque. By taking out only the necessary measurements and calculating torque-producing current directly without full Clarke transform, the system achieves sufficient measurement precision while minimizing computational complexity and noise.

The patent uses partial action by measuring only two of the three phase currents instead of all three phases. This partial measurement approach provides sufficient information for torque control without the computational overhead and noise associated with processing all three phases through the complete Clarke transform, achieving the right balance between precision and complexity.