Electronic control unit for electric power steering

An electronic control apparatus configured to control electric power steering and provided integrally with an electric motor, the electronic control apparatus which is electrically connected to an ignition switch and which assists a rotation operation of a steering column by rotation of the electric motor, the electronic control apparatus comprising:

• a magnetic body attached to a rotation shaft of the electric motor and provided with a pole face including a plurality of magnetic poles arranged at equal or substantially equal intervals in a circumferential direction of the rotation shaft;
• a first magnetism detecting element located at a position opposite to the pole face and configured to operate using power supplied via the ignition switch to output a first set of rotation angle signals of the electric motor;
• a second magnetism detecting element located at the position opposite to the pole face and configured to operate continuously using continuously supplied power supplied directly from a power source to output a second set of rotation angle signals of the electric motor;
• and
• a controller configured or programmed to generate rotation angle information about the electric motor based on the first set of rotation angle signals when the ignition switch is operated and based on the second set of rotation angle signals outputted while the ignition switch is stopped, the controller also being configured or programmed to calculate a position of a steering wheel from the generated rotation angle information.