Current sensor, sensor element, and control device
AssigneeFerrotec Corpotation
InventorsTakayuki Hachida, Yasukake Hirota
Life of this patent
Estimating the term…
Abstract
A current sensor according to the present invention includes a sensor element and a detector. The sensor element includes a core member, an exciting coil and a detection coil. The sensor element is configured such that, while the exciting coil is fed with an excitation signal, comprising a fundamental component, and when the signal to be detected flows, a signal, including a harmonic component, corresponding to the permeability μ of the core member at that point, being superposed on the fundamental component, is outputted from the detection coil. The detector includes a component extraction unit, a level specification unit, and an information output unit.
Claims13
A current sensor comprising a sensor element and a detector,
- the sensor element comprising:
- a core member, annularly formed with a magnetic material, and having characteristics such that, corresponding to an external magnetic field that changes due to influence of a signal to be detected that passes through a detection area surrounded by the annularity, a permeability μ decreases from a vertex where the external magnetic field is 0, and such that curvature of a curve, exhibited when a change in the permeability μ is plotted in “a coordinate system defined by the external magnetic field—the permeability μ”, becomes larger corresponding to absolute values of the external magnetic field;
- an exciting coil wound around the core member so as to excite the core member;
- and
- a detection coil wound around the core member and used so as to detect the signal to be detected,
- the sensor element being configured such that, while the exciting coil is fed with an excitation signal, comprising a fundamental component, and when the signal to be detected flows, a signal, including a harmonic component, corresponding to the permeability μ of the core member at that point, being superposed on the fundamental component, is outputted from the detection coil, and
- the detector comprising:
- a component extraction unit that extracts, from the output signal of the detection coil, the harmonic component superposed on the fundamental component among signal components included in the output signal;
- a level specification unit that specifies a signal level corresponding to the harmonic component, extracted by the component extraction unit, as the signal level of the signal to be detected at that point based on a corresponding relationship between the harmonic component, potentially included in the output signals, and the signal level of the signal to be detected when the harmonic component is generated;
- and
- an information output unit that outputs information externally, indicating the signal level specified by the level specification unit.
A sensor element comprising:
- a core member, annularly formed with a magnetic material, and having characteristics such that, corresponding to an external magnetic field that changes due to influence of a signal to be detected that passes through a detection area surrounded by the annularity, a permeability μ decreases from an vertex where the external magnetic field is 0, and such that curvature of a curve, exhibited when a change in the permeability μ is plotted in “a coordinate system defined by the external magnetic field—the permeability μ”, becomes larger corresponding to absolute values of the external magnetic field;
- an exciting coil wound around the core member so as to excite the core member;
- and
- a detection coil wound around the core member and used so as to detect the signal to be detected,
- the sensor element being configured such that, while the exciting coil is fed with an excitation signal, comprising a fundamental component, and when the signal to be detected flows, a signal, including a harmonic component, corresponding to the permeability μ of the core member at that point, being superposed on the fundamental component, is outputted from the detection coil.
Dependencies are inferred from the claim text.