A method for the diagnosis of the offset of the resolver of an electric motor, comprising acquiring a predetermined offset of a resolver associated with the electric motor; in a first transient, supplying an excitation current to the phases of the electric motor. As a consequence of the excitation current, a current established on the axis d of minimum reluctance and a current established on an axis q in phase quadrature with respect to the axis of minimum reluctance are determined. The correctness of the offset of the resolver is diagnosed if the current established on the axis d in the first transient is higher than the current established on the axis d in the second or third transient, and if the current established on the axis q in the first transient is lower than the current established on the axis q in the second or third transient.

An electromagnetic inductive encoder that can suppress the effect of changes in magnetic flux received by the receiver section and maintain the accuracy of measurement results is provided. The electromagnetic inductive encoder 1 includes a scale 2 and a head 3 that is provided to face the scale 2 and moves relative to the scale 2. The head 3 includes a transmitter section 4 and a receiver section 5 with a plurality of receiving coils 500. The receiver section 5 has a first receiver section 51 with at least one receiving coil 500, a second receiver section 52 that is provided apart from the first receiver section 51 and has at least one receiving coil 500 different from the first receiver section 51, and connection wiring 53 that connects the first receiver section 51 and second receiver section 52. The first receiver section 51 and the second receiver section 52 are arranged linearly symmetrically with the axis L1 of the Y-direction, which is orthogonal to the X-direction (measurement direction) in the plane 30 where the receiving coils 500 are arranged, and are arranged in the same number.

A resolver system includes a rotatable primary winding, a secondary winding fixed relative to the primary winding, and an analog-to-digital converter electrically connected to the secondary winding. A control module is operatively connected to analog-to-digital converter and is responsive to instructions to apply an excitation voltage with an oscillating waveform to the primary winding, induce a secondary voltage using the secondary winding using the excitation voltage, and acquire a plurality of voltage measurements from the secondary winding separated by a time interval corresponding to π/3 of the excitation voltage oscillating waveform.

A diagnostic device capable of accurately diagnosing the soundness of a resolver circuit is provided. A shifter receives excitation signal and excitation signal; shifts the level of excitation signal, excitation signal, or both; and performs level shifting such that a period of time that starts with one of two times in which, in the vicinity of the peak value of excitation signal, excitation signal and excitation signal are at the same value and ends with the other of the two times is less than a prescribed threshold. A trigger generation circuit generates a trigger during said period of time. A control unit determines whether there is an abnormality in the resolver circuit on the basis of the trigger.

An inductive position detector with a first and second body, at least one of said bodies being displaceable relative to the other along a measurement path wherein said first body comprises one or more antenna windings forming a first arrangement of windings and said second body comprises a passive resonant circuit incorporating one or more target windings in series with a capacitor; said circuit covering at least in part said first arrangement; characterized in that said first body comprises an additional winding arrangement disposed along at least part of said measurement path; said additional winding arrangement being spaced from said first arrangement of windings; and said second body comprises an additional winding arrangement covering at least in part said additional winding arrangement of said first body.

A resolver excitation signal generator includes a source configured to generate a sinusoidal input signal and an inverting amplifier circuit. The inverting amplifier circuit has an input connected to the source to receive the sinusoidal input signal and an output lacking a transistor stage. The inverting amplifier circuit is configured to amplify the sinusoidal input signal to generate at the output of the inverting amplifier circuit an excitation signal in the form of an amplified version of the sinusoidal input signal for a resolver.

A rotation detector includes the following: a rotor and stators comprising a rotor substrate and stator substrates, each of which is a multilayer substrate; a rotor coil provided on the rotor substrate; and detection coils provided on the stator substrates. The frequency of an excitation signal used by said rotation detector is set so as to be higher than a prescribed frequency that would be required if the rotor and the stators were each made of a magnetic material.

A position signal generator for an electronic position measuring device is disclosed. In an embodiment, the position signal generator includes a signal generation device for generating a periodic magnetic signal, and an electric power supply device for supplying the signal generation device with electric energy. The position of the position signal generator is determined via the position measuring device.

To provide a correction method of resolver correction device and resolver correction device that can reduce rotation angle (the rotation speed) detection error caused by resolver. An excitation signal supply circuit supplies an excitation signal of an excitation frequency to the resolver during a normal operation, for supplying the excitation signals of a plurality of frequencies including the excitation frequency to the first phase shifter or the second phase shifter during a calibration operation. A shift amount searching circuit searches the first shift amount setting value for each frequency of the excitation signal such that the first shift amount becomes 45 degrees, and the second shift amount setting value for each frequency of the excitation signal such that the second shift amount becomes 135 degrees, while referring to the detection result of the phase difference detection circuit during the calibration operation, and stores in the correction table.

A device for monitoring a resolver disposed on a rotatable member is described herein, and includes a controller including a microprocessor circuit and an interface circuit connected to the resolver, wherein the microprocessor circuit includes a dual-core central processing unit (CPU), a pulse generator, a sigma-delta analog-to-digital converter (SDADC), a global memory device, an internal communication bus and a direct memory access device (DMA). The microprocessor circuit is disposed to control the pulse generator to generate an excitation pulse transferable to the excitation winding of the resolver, and control the SDADC to capture data from the secondary windings of the resolver and store the captured data in the memory buffer. A control routine is executed to detect an envelope for the captured data, and a rotor position for the resolver is determined based upon the detected envelope.