US 8,947,077 B2Granted

Rotary position sensor

AssigneeKSR IP Holdings, LLC

InventorsJoong K. Lee, Lingmin Shao, Ryan Elliott

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Abstract

A rotary position sensor having a transmitter coil excited by a high frequency signal source. A first and second receiver coil, each having at least two oppositely wound loops, are rotatably positioned electrically 90 degrees relative to each other. The receiver coils are positioned so as to be inductively coupled with the transmitter coil while a coupler constructed of an electrically conductive material is rotatably positioned over and inductively coupled with the first and second receiver coils. The outputs from the first and second receiver coils are coupled through a high pass filter and a low pass filter, respectively, thus creating a 90° phase shift in the resultant signals. These signals are summed together and coupled as an input signal to a PWM circuit together with a signal from the transmitter coil.

Claims8

Dependent claims

A rotary position sensor comprising:

a transmitter coil adapted to be excited by a high frequency signal source,
a first receiver coil having at least two oppositely wound loops, said first receiver coil being inductively coupled with said transmitter coil,
a second receiver coil having at least two oppositely wound loops, said second receiver coil being rotatably positioned electrically 90 degrees relative to said first receiver coil and inductively coupled with said transmitter coil,
a coupler constructed of an electrically conductive material and having at least two lobes, said coupler rotatably positioned over and inductively coupled with said first and second receiver coils,
a signal summer having two inputs and an output,
said first receiver coil electrically connected through a low pass filter to one input of said signal summer,
said second receiver coil electrically connected through a high pass filter to the other input of said signal summer,
said output of said signal summer electrically connected to a pulse width modulation circuit which produces an output with a duty cycle proportional to the angle of rotation of said coupler.

5 more elements

Dependencies are inferred from the claim text.