Capacitive position sensor
First Claim
1. A capacitive position sensor, particularly an angular position sensor for use in connection with a throttle valve of an internal combustion engine, comprisinga capacitor arrangement (2) having two facing electrode structures (3, 4) supported for movement relative to each other, one of said electrode structures including at least three coplanar electrodes (21, 22, 23) and the other electrode structure including at least a planar counter-electrode (25);
- means for applying a first a.c. voltage (u1) to a first electrode (21), and a second a.c. voltage (u2) of equal amplitude and of opposite phase to a second electrode (22) of said one electrode structure;
regulating means for applying a third a.c. voltage (uR) to a third electrode (23) of said one electrode structure, said regulating means being coupled to said counterelectrode (25) of the other electrode structure to regulate said third a.c. voltage (uR) to an amplitude and phase value at which an a.c. voltage which has been induced by said first, second and third electrodes (21, 22,
23) on said counterelectrode (25), is neutralized to zero; and
means for converting the neutralizing value of said third a.c. voltage (uR) into a d.c. voltage value (UA) serving as a measure of the relative position of said movable electrode structures (3,
4).
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Accused Products
Abstract
A capacitive position sensor includes a capacitor arrangement assembled of a stator (5) and a rotor (6). The stator supports at least three coplanar electrodes (21, 22, 23) having the shape of circle sectors 120°. The rotor supports at least a counterelectrode (25) having the shape of a circle sector of 240°. An oscillator (30) applies two a.c. voltage (u1, u2) of equal amplitude and opposite phase to two of the stator electrode (21, 22). The range of rotation of the rotor is such that the remaining third electrode on the stator is always overlapped by the counterelectrode. Voltage induced on the counterelectrode by means of the a.c. voltages on the stator electrodes is inverted and fed back as a neutralizing voltage (uR) to the third stator electrode (23) until the induced voltage on the counterelectrode reaches zero value. The neutralizing voltage is rectified and integrated into a d.c. voltage (UA) which serves as a measure of the angular position of the rotor (6).
58 Citations
18 Claims
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1. A capacitive position sensor, particularly an angular position sensor for use in connection with a throttle valve of an internal combustion engine, comprising
a capacitor arrangement (2) having two facing electrode structures (3, 4) supported for movement relative to each other, one of said electrode structures including at least three coplanar electrodes (21, 22, 23) and the other electrode structure including at least a planar counter-electrode (25); -
means for applying a first a.c. voltage (u1) to a first electrode (21), and a second a.c. voltage (u2) of equal amplitude and of opposite phase to a second electrode (22) of said one electrode structure; regulating means for applying a third a.c. voltage (uR) to a third electrode (23) of said one electrode structure, said regulating means being coupled to said counterelectrode (25) of the other electrode structure to regulate said third a.c. voltage (uR) to an amplitude and phase value at which an a.c. voltage which has been induced by said first, second and third electrodes (21, 22,
23) on said counterelectrode (25), is neutralized to zero; andmeans for converting the neutralizing value of said third a.c. voltage (uR) into a d.c. voltage value (UA) serving as a measure of the relative position of said movable electrode structures (3,
4). - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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Specification