In-Vehicle Resolver Alignment via Current Sweep

The patent performs a preliminary alignment procedure during system initialization or setup. The controller applies current to the electric machine windings and measures the resulting voltage signals to determine the actual alignment between the resolver and rotor flux field. This preliminary measurement allows the system to establish a reference offset value that compensates for manufacturing tolerances before normal operation begins.

The patent changes the operating parameters of the electric machine to enable alignment detection. By applying specific current magnitudes and measuring voltage signals at different operating points, the system identifies the angular offset between the resolver and rotor flux field. The controller then uses this information to adjust the reference frame transformation parameters, ensuring accurate rotor position determination despite physical misalignment.

The controller performs the alignment determination autonomously using built-in measurement capabilities. The system applies test currents to the motor windings, measures the resulting voltage signals through existing sensors, and automatically calculates the resolver offset without requiring external alignment equipment or manual intervention. This self-service approach improves measurement accuracy while avoiding the need for additional complex alignment apparatus.

The patent implements a feedback mechanism where the controller measures voltage signals during the alignment procedure and uses this information to determine the correct offset value. The system continuously monitors the relationship between applied current and measured voltage to identify the angular position where the rotor flux field aligns with the resolver, then applies this feedback to correct all subsequent position measurements.

The alignment calibration is performed as a preliminary action during system initialization, vehicle startup, or during scheduled maintenance intervals rather than during normal propulsion operation. The controller executes the alignment procedure by applying predetermined current magnitudes and measuring voltage signals to determine the resolver offset, then stores this information for use during subsequent normal operation when full propulsion performance is required.

The patent implements periodic alignment calibration where the controller performs the alignment procedure at predetermined intervals or under specific conditions such as when the vehicle is stationary or during low-demand periods. This periodic execution ensures that alignment accuracy is maintained over time while minimizing the impact on overall vehicle productivity, as the calibration events are brief and occur during non-critical operational windows.