Cooking article detection system with differential detection coils

An induction cooktop, including:

• a first power-delivery induction coil;
• a first detector including:
• a first detector coil overlying the first power-delivery induction coil and including a first conductive element revolving continuously around a first centroid in a first tangential direction to define a shape of the first detector coil that extends in a first linear direction and a second linear direction along a first plane;
• and
• a second detector coil overlying the first power-delivery induction coil and including a second conductive element connected with the first conductive element and revolving continuously around a second centroid in a second tangential direction, opposite the first tangential direction, to define a shape of the second detector coil that extends in the first direction and the second direction along the first plane, the second detector coil being linearly arranged with the first detector coil and spaced apart therefrom in the second linear direction;
• a second detector having third and fourth detection coils;
• and
• a controller alternately driving a selected one of the first detector and the second detector with the detection signal and measures the voltage across the selected one of the first detector and the second detectors, wherein driving the first detector includes driving the first and second detection coils, simultaneously, with a low-voltage, high frequency detection signal, and measuring a voltage across the first and second detection coils to identify a cooking article on the induction cooktop over the first power-delivery induction coil by the voltage being below a predetermined threshold value.

A method for detecting a cooking article in place on an induction cooktop including a first power-delivery induction coil, comprising:

• driving a first detection coil and second detection coil, simultaneously, with a low-voltage, high frequency detection signal, the first detector coil overlying the first power-delivery induction coil and including a first conductive element revolving continuously around a first centroid in a first tangential direction to define a shape of the first coil that extends in a first linear direction and a second linear direction along a first plane, and the second detector coil overlying the first power-delivery induction coil and including a second conductive element connected with the first conductive element and revolving continuously around a second centroid in a second tangential direction, opposite the first tangential direction, to define a shape of the second coil that extends in the first direction and the second direction along the first plane, the second detector coil being linearly arranged with the first detector coil and spaced apart therefrom in the second linear direction;
• and
• operating the first power-delivery induction coil, by providing an operating voltage thereto, simultaneously with driving the first and second detection coils and simultaneously measuring a voltage across the first and second detection coils, to identify a cooking article on the induction cooktop over the first power-delivery induction coil by the voltage being below a predetermined threshold value.