A method and apparatus is disclosed for allowing a magnetic tracking system to detect, and operate in close proximity in the same physical environment with, additional magnetic tracking systems. The first user's magnetic tracking system that becomes active in the physical space becomes the master system, and assigns time slots for its own transmitting antennas to generate the magnetic field which is used to determine the position and orientation of the user's limbs relative to the user's head. The master system also determines when other magnetic tracking systems become active in the physical space and assigns to those systems identification codes and time slots for their transmitting antennas to generate a magnetic field so that the position and orientation of the user's hands relative to the user's head for each of those systems may be determined. By requiring each magnetic tracking system to operate in different time slots, there is no interference between the systems.

A rotational angle sensor includes a stator element and a rotor element. The stator element has a stator transmitting coil, a stator circuit board with first and second planes, and at least two identically configured stator receiving coils arranged within the stator transmitting coil on the stator circuit board angularly offset from each other. The rotor element is mounted rotatably about a rotational axis relative to the stator element. The stator transmitting coil is inductively coupled to the stator receiving coils via the rotor element such that the inductive coupling is configured with reference to a rotational angle between the stator element and the rotor element so that the stator transmitting coil induces at least two angle-dependent alternating voltages in the stator receiving coils. The stator transmitting coil has coil conducting tracks positioned on the first and second planes of the stator circuit board. The coil conducting tracks on the first plane are interrupted in a passage region, and are connected to diverting tracks on the second plane by vias. The stator receiving coils have connection conductors on the first plane lead from stator receiving coil connections within the stator transmitting coil, through the passage region, and to circuit board connections for the stator receiving coils. Each connection conductor is curved so as to form a conductor loop in order to compensate differently sized coil areas of the stator receiving coils formed by connection conductors of different lengths within the stator transmitting coil.

Systems, devices, and methods for determining a position of a target using an inductive position sensor are described. The inductive position sensor may include a rotor, two or more excitation coils, and two or more receive coils. Each of the coils and the rotor may be inductively coupled. The two or more receive coils may be configured to generate a received voltage which can be approximated by a sine waveform function of twice the rotor's position. The inductive position sensor may include a resonant component. The resonance component may be connected to one of the two or more excitation coils or the rotor. An integrated circuit may be configured to determine the position of the rotor based on the two or more received voltages.

A detection device and a detection method of a rotor position of three-phase motor are disclosed which measure induced voltages under different voltage vectors and calculate an induced voltage relationship among the different induced voltages. Then the detection device and the detection method find out the rotor position suitable for the induced voltage relationship according to a rotor position table. Therefore, the detection device and the detection method can accurately detect the rotor position in a standstill state to prevent the three-phase motor from operating abnormally and burning out.

A detection device and a detection method of a rotor position of three-phase motor are disclosed which measure induced voltages under different voltage vectors and calculate an induced voltage relationship among the different induced voltages. Then the detection device and the detection method find out the rotor position suitable for the induced voltage relationship according to a rotor position table. Therefore, the detection device and the detection method can accurately detect the rotor position in a standstill state to prevent the three-phase motor from operating abnormally and burning out.

A system includes a rotary device, a vector-based position sensor outputting raw sine and cosine signals indicative of an angular position of the rotary device, and a controller. The controller executes a method by receiving the raw sine and cosine signals from the sensor, generating corrected sine and cosine signals by applying an amplitude error input signal to a first integrator block using a first predetermined trigonometric relationship, and executing a control action for the rotary device via output signals using the corrected signals. The first predetermined trigonometric relationship is S.sub.C.sup.2C.sub.C.sup.2, with S.sub.C and C.sub.C being the respective corrected sine and cosine signals. The controller may use a second predetermined trigonometric relationship, S.sub.C.Math.C.sub.C, to apply an orthogonality error input signal to a second integrator block.

An inductive sensor may track an angle of a movable element. In some cases, it is desirable to operate the inductive sensor using battery power so that turns are tracked properly even when power is lost. The disclosed inductive sensor includes circuitry to conserve power, such as a non-resonant driver that allows for fast measurements without wasting energy and a difference encoder that can estimate the angle within a range without the need for digitization and complicated processing.

A system includes a rotary device, a vector-based position sensor outputting raw sine and cosine signals indicative of an angular position of the rotary device, and a controller. The controller executes a method by receiving the raw sine and cosine signals from the sensor, generating corrected sine and cosine signals by applying an amplitude error input signal to a first integrator block using a first predetermined trigonometric relationship, and executing a control action for the rotary device via output signals using the corrected signals. The first predetermined trigonometric relationship is S.sub.C.sup.2-C.sub.C.sup.2, with S.sub.C and C.sub.C being the respective corrected sine and cosine signals. The controller may use a second predetermined trigonometric relationship, S.sub.C.Math.C.sub.C, to apply an orthogonality error input signal to a second integrator block.

An angular resolver system includes, for example, an imbalance detector for detecting degraded resolver output signals. The imbalance detector includes a first and second power averaging circuits and a comparator circuit. The first power averaging circuit includes a first integrator for generating over a first time window a first average power signal in response to resolver sensor output signals. The second power averaging circuit includes a second integrator for generating over a second time window a second average power signal in response to the resolver sensor output signals, where the first time window is longer than the second time window. The comparator circuit compares the first average power signal and the second average power signal and generates a fault signal when the first average power signal and the second average power signal differ by a selected voltage threshold.

In an apparatus for controlling a rotary electric machine, a voltage applier applies a high-frequency voltage to one of the field winding and the armature winding. One of a field winding and an armature winding is defined as an input winding, and the other thereof is defined as an output winding. A current detector detects a high-frequency current flowing through the output winding based on the applied high-frequency voltage. The high-frequency current includes therein information associated with the rotational position of a target magnetic pole of the rotor as a predetermined one of the magnetic poles. An estimator estimates the rotational position of the target magnetic pole of the rotor according to the high-frequency current detected by the current detector.