Low-cost modular inductive position sensor and method of manufacturing it

A position sensor for positioning a shaft of an electrical motor, the position sensor comprising:

• a plurality of E-shaped ferromagnetic cores arranged to define a circular opening therethrough to receive a shaft, each E-shaped ferromagnetic core having at least a middle tooth, a first side tooth, and a second side tooth, the second side tooth of each E-shaped ferromagnetic core at least partially overlapping the first side tooth of an adjacent E-shaped ferromagnetic core of the arranged plurality of E-shaped ferromagnetic cores and thereby defining a set of overlapping side teeth;
• a first plurality of electromagnetic coils, each electromagnetic coil positioned around a respective set of overlapping side teeth;
• a second plurality of electromagnetic coils, each electromagnetic coil positioned around a respective middle tooth;
• and
• a control circuit coupled to the electromagnetic coils of the first plurality of electromagnetic coils and the second plurality of electromagnetic coils, the control circuit configured to receive position signals from the electromagnetic coils and control power supplied to the electromagnetic coils of the first plurality of electromagnetic coils to cause rotation of the shaft based on the received position signals.

A position sensor for positioning a shaft of an electrical motor, the position sensor comprising:

• a plurality of E-shaped ferromagnetic cores arranged to define a circular opening therethrough to receive a shaft, each E-shaped ferromagnetic core having at least a middle tooth, a first side tooth, and a second side tooth, the second side tooth of each E-shaped ferromagnetic core at least partially overlapping the first side tooth of an adjacent E-shaped ferromagnetic core of the arranged plurality of E-shaped ferromagnetic cores and thereby defining a set of overlapping side teeth, wherein a first set of the plurality of E-shaped ferromagnetic cores are arranged in a first plane and a second set of the plurality of E-shaped ferromagnetic cores are arranged in a second plane, the first and second planes being parallel to define a z-axis offset;
• a first plurality of electromagnetic coils, each electromagnetic coil positioned around a respective set of overlapping side teeth, wherein a first set of opposing electromagnetic coils of the first plurality of electromagnetic coils define an x-axis offset and a second set of opposing electromagnetic coils of the first plurality of electromagnetic coils define a y-axis offset;
• a second plurality of electromagnetic coils, each electromagnetic coil positioned around a respective middle tooth;
• and
• a control circuit coupled to the electromagnetic coils of the first and second pluralities of electromagnetic coils, the control circuit configured to receive position signals corresponding to a relative position of the x-, y-, and z-axis offsets, and control power supplied to the electromagnetic coils of the first plurality to cause rotation of the shaft based on the received position signals.

A rotating device having a sensor for positioning a rotatable shaft, the rotating device comprising:

• a plurality of E-shaped ferromagnetic cores arranged to define a circular opening therethrough to receive a shaft, each E-shaped ferromagnetic core having at least a middle tooth, a first side tooth, and a second side tooth, the second side tooth of each E-shaped ferromagnetic core at least partially overlapping the first side tooth of an adjacent E-shaped ferromagnetic core of the arranged plurality of E-shaped ferromagnetic cores and thereby defining a set of overlapping side teeth;
• a frame surrounding the plurality of E-shaped ferromagnetic cores, the E-shaped ferromagnetic cores coupled to the frame, the frame and the coupled E-shaped ferromagnetic cores defining a stator;
• a first plurality of electromagnetic coils, each electromagnetic coil positioned around each respective set of overlapping side teeth;
• a second plurality of electromagnetic coils, each electromagnetic coil positioned around a respective middle tooth;
• a shaft positioned within the circular opening of the plurality of E-shaped ferromagnetic cores, the shaft configured as a rotor such that the shaft is permitted to rotate within the circular opening along a longitudinal axis passing through the circular opening;
• and
• a control circuit coupled to the electromagnetic coils of the first and second pluralities of electromagnetic coils, the control circuit configured to receive position signals from the electromagnetic coils and control power supplied to the electromagnetic coils of the first plurality to cause rotation of the shaft based on the received position signals.