A redundant resolver is configured of a stator and a rotor that form a pair, wherein the rotor is a rotor with a shaft angle multiplier of Nx having Nx (Nx is a natural number) salient poles, the stator is such that n teeth T1 to Tn, where n is a natural number, are disposed sequentially in a circumferential direction, configuring M systems by being divided into M in the circumferential direction, and having an angle of 360/M degrees when angles of the teeth configuring one system are totaled, a one-phase excitation winding and a two-phase output winding are wound around each of the teeth T1 to Tn, excitation signals of the same frequency are applied by differing excitation circuits to the respective excitation windings, an output order per system is Nout (Nout is a natural number), and an abnormality is detected based on output signals of the M systems.

Systems and methods are provided for anesthetic agent level sensing. In one embodiment, a system for an inductive level sensor for an anesthetic vaporizer includes a measurement target positioned around a rod that extends within a chamber configured to hold liquid anesthetic agent, the rod configured to be at least partially submerged in the liquid anesthetic agent and the measurement target configured to slide vertically along a length of the rod and rest on a surface of the liquid anesthetic agent, and a strip of inductive transmitter coils and receiver coils positioned external to the chamber, a length of the strip aligned with the length of the rod, the transmitter coils configured to generate a magnetic field that surrounds the rod and the measurement target and the receiver coils configured to sense changes in the generated magnetic field at a vertical location of the measurement target on the rod.

A position sensor includes a plurality of E-shaped ferromagnetic cores arranged to define a circular opening therethrough to receive a shaft. Each E-shaped ferromagnetic core has a plurality of teeth, wherein adjacent E-shaped ferromagnetic cores of the arranged plurality of E-shaped ferromagnetic cores have an overlapping tooth. The position sensor further includes a frame surrounding the arranged plurality of E-shaped ferromagnetic cores, with the E-shaped ferromagnetic cores coupled to the frame.

The redundant resolver includes: a resolver body having a rotor, a stator opposed to the rotor and having Ns teeth arranged in a circumferential direction, and an excitation winding and two phases of output windings wound on the stator; an excitation circuit configured to supply power to the excitation winding; and an angle calculation unit configured to calculate a rotation angle on the basis of signals from the two phases of output windings. The stator is divided in the circumferential direction into M pieces which serve as M tooth blocks, N (M≥N) redundancy systems are formed on the basis of the M tooth blocks. The excitation circuit and the angle calculation unit are provided to each system so as be independent among the systems. Gap magnetic flux densities at both end portions of each tooth block are set to change mildly.

A target configured to be used with a position sensor for sensing a position of the target is described. The target includes at least one elongated conductive loop structure for allowing eddy currents to flow therein and configured to affect a magnetic field received from the position sensor in a preferred direction along the at least one elongated conductive loop structure.

A method of determining an angular position of a target of an inductive angular position sensor system, relative to a substrate, includes the steps of: receiving, demodulating and digitizing signals, and reducing a DC-offset of the digital signals, and determining an angular position. The step of reducing the DC-offset involves: i) initializing a DC-correction value; ii) subtracting the DC-correction value to obtain DC-shifted signals; iii) clipping the DC-shifted-signals to obtain clipped signals; iv) calculating a first sum by summing values of the clipped signal over one period, and v) calculating a second sum by summing absolute values of the clipped signal over said period; vi) adding to each DC correction value K times the first sum divided by the second sum, where K is a predefined constant.

An angular position sensor for sensing the angular position of a rotor rotating on an axis relative to a stator, including a ferromagnetic target, of substantially ovoid cross section, rotating together with one from among the rotor or the stator, and a sensitive element including a first set of coils that are angularly evenly distributed, rotating together with the other from among the rotor or the stator, the coils being axially arranged in line with the target in order to be able to measure a distance from the target so as to deduce therefrom an angular position of the rotor relative to the stator.

To solve a problem that the accuracy of angle detection deteriorates owing to noise voltage generated by eccentricity or variation in shape among rotors according to the number of magnetic poles of a rotor core of a multiple-system rotation sensor, the number S of magnetic poles of a stator core is, with the number R of the magnetic poles of the rotor core and the number N (N is a natural number equal to or larger than 2) of systems for stator windings, in a relationship of S=nRN (n is a natural number), system windings of each system are wound so as to be divided for every R magnetic poles among the S magnetic poles of the stator core, and a winding arrangement of the system windings of each system is made so as to achieve R-times rotational symmetry about a rotor rotation axis.

A resolver body including a rotor having Nx (Nx is a natural number) salient poles, a stator facing the rotor and having Ns (Ns is an integer equal to or larger than 3) teeth arranged in a circumferential direction, and an excitation winding and two phases of output windings wound on each tooth; and an excitation circuit configured to apply voltage to the excitation winding. The excitation winding and the two phases of output windings wound on each of Nsm (Nsm is an integer equal to or larger than 2) teeth among the Ns teeth are set to be of a main system. The excitation winding and the two phases of output windings wound on each of Ns-Nsm teeth are set to be of a sub-system. The number Nsm of the teeth corresponding to the main system is larger than the number Ns-Nsm of the teeth corresponding to the sub-system.

An inductive angle measuring device includes a scanning element and a scale element having scale tracks. First and third scale tracks have an equal first number of scale structures, and a second scale track has a different number of scale structures. The scale tracks are arranged circumferentially and concentrically about an axis, such that the first scale track is located radially inwardly, the second scale track is located radially between the first scale track and the third scale track, and the third scale track is located radially outwardly. The scanning element includes receiver conductors by which the signals having angle-related signal periods can be generated. The first signal period is equal to the third signal period. An overall signal can be generated from the first signal and the third signal and can be combined with the second signal for determining absolute angle position information.