Rotor position detection circuit and motor driving device
AssigneeDenso Corporation
InventorAtsushi Kanamori
Life of this patent
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Abstract
A rotor position detection circuit detects a position of a rotor in a motor from a detection signal of an induced voltage generated in a stator coil. The circuit includes: a first low pass filter having a first reference potential for filtering the detection signal; a comparator for comparing an output signal from the first low pass filter with a predetermined reference voltage and for outputting a rotation position signal; and a second low pass filter having a second reference potential for filtering a virtual neutral point potential of the motor. The first reference potential is the filtered virtual neutral point potential, and the second reference potential is a ground.
Claims16
A rotor position detection circuit for detecting a position of a rotor in a motor based on a detection signal of an induced voltage, which is generated in a stator coil in the motor, the circuit comprising:
- a first low pass filter circuit for filtering the detection signal in a low frequency range, wherein the first low pass filter circuit has a first reference potential;
- a comparator for comparing an output signal from the first low pass filter circuit with a predetermined reference voltage and for outputting a rotation position signal based on a comparison between the output signal and the predetermined reference voltage;
- and
- a second low pass filter circuit for filtering a virtual neutral point potential of the motor in a low frequency range, wherein the second low pass filter circuit has a second reference potential, wherein
- the first low pass filter circuit is a single low pass filter provided by a first capacitor and a first resistor,
- the second low pass filter circuit is a single low pass filter provided by a second capacitor and a second resistor,
- the first reference potential of the first low pass filter circuit is the filtered virtual neutral point potential of the second low pass filter circuit, and
- the second reference potential of the second low pass filter circuit is a ground.
A rotor position detection circuit for detecting a rotation position of a rotor in a motor based on a detection signal of an induced voltage, which is generated in a stator coil in the motor, the circuit comprising:
- a first low pass filter circuit for filtering the detection signal in a low frequency range, wherein the first low pass filter circuit has a first reference potential;
- a comparator for comparing an output signal from the first low pass filter circuit with a predetermined reference voltage and for outputting a rotation position signal based on a comparison between the output signal and the predetermined reference voltage;
- and
- a second low pass filter circuit for filtering a neutral point potential of the motor in a low frequency range, wherein the second low pass filter circuit has a second reference potential, wherein
- the first low pass filter circuit is a single low pass filter provided by a first capacitor and a first resistor,
- the second low pass filter circuit is a single low pass filter provided by a second capacitor and a second resistor
- the first reference potential of the first low pass filter circuit is the filtered neutral point potential of the second low pass filter circuit, and
- the second reference potential of the second low pass filter circuit is a ground.
Dependencies are inferred from the claim text.