Method for automatically setting an angular position sensor

A method for automatically setting an angular position sensor measuring an angle corresponding to the mechanical angular position of an armature rotor with a magnet forming P pole pairs relative to a stator comprising X phases of a multiphase synchronous electric motor of an electric machine of an aircraft propulsion unit, the position sensor comprising a movable part mounted to the armature rotor and a fixed part relative to the stator, the method using a control loop to transmit a command to an inverter converter of the electric machine to supply the phases of the stator, the control loop comprising a current controller comprising a setpoint input to receive a current setpoint comprising a setpoint quadrature current corresponding to a component on the quadrature axis of the setpoint current vector and a setpoint direct current corresponding to a component on the direct axis of the setpoint current vector, to deliver a voltage setpoint comprising a quadrature and direct voltage with an angle, a calculation unit to calculate a direct Park and inverse Park transformation, for transforming the voltage setpoint into a command of the inverter converter, an angle error compensator to identify an angle error and compensate for it, the method being characterised in that it comprises a speed-based position sensor error identification part, the method comprising:

• calculating the command of the inverter converter in order to rotate the armature rotor at a predetermined mechanical speed constantly,
• measuring the phase currents and transforming them in a Park reference frame, into the return quadrature current and the return direct current, taking account of an adjusted angle calculated,
• calculating an electrical speed (@elec) of the rotor by multiplying the number p of pole pairs by the predetermined mechanical speed,
• calculating a voltage setpoint for a period t during which the rotor rotates at the predetermined mechanical speed by imposing a direct current value equal to 0 on the current controller,
• identifying an offset error of the direct component on its direct axis by comparing during the period t the direct voltage of the voltage setpoint with a value of opposite sign, the value being equal to the electrical speed calculated multiplied by a quadrature inductance multiplied by the return quadrature current,
• identifying an offset error of the quadrature component on its quadrature axis by comparing, during the period t, the quadrature voltage of the voltage setpoint with a first value equal to the electrical speed of the rotor calculated multiplied by a predetermined value corresponding to the flux of the rotor magnets,
• calculating an angular difference value from these direct and quadrature angular offset errors identified,
• determining at the period t, an adjusted angle as a function of the angular difference value calculated, and the measured angle value,
• transmitting the return quadrature current and the return direct current according to the adjusted angle to the current controller.