Phase-Voltage Calibration Circuit for Rotor Position Offset Correction

The patent introduces an intermediary calibration process that uses phase voltage measurements as a mediator to determine the actual rotor position. Instead of relying solely on the position sensor, the system uses the relationship between phase voltages and rotor position (where phase voltages are in phase with magnetic flux when current is null) to calculate the true angular position and compare it with sensor readings, thereby identifying and correcting sensor errors.

The patent implements a feedback mechanism where the measured phase voltages are used to calculate the actual rotor position, which is then fed back to correct the position sensor readings. This feedback loop allows the system to compensate for sensor errors by continuously comparing sensor output with the calculated position from voltage measurements, ensuring accurate position data for control purposes.

The patent makes the existing phase voltage measuring circuit serve multiple functions: it continues to provide voltage information for current control while simultaneously enabling rotor position determination during calibration. By extracting position information from the same voltage measurements used for control, the system avoids adding dedicated position measurement hardware, thus achieving multi-functionality without increasing device complexity.

The system uses its own existing phase voltage measurement capability to perform the calibration function. Instead of requiring external or separate measurement equipment, the electric machine's built-in voltage sensing infrastructure is utilized to determine rotor position, allowing the system to self-calibrate using resources already available within the device.