Signal converter and control device

Patent metadata

Field	Value
Publication number	US-9832054-B2
Application number	US-201715484285-A
Country	US
Kind code	B2
Filing date	Apr 11, 2017
Priority date	Aug 5, 2015
Publication date	Nov 28, 2017
Grant date	Nov 28, 2017

Abstract

A signal converter 100 includes, for at least two-phase signals detected by a resolver excited by a carrier signal having a carrier frequency fc, a first phase shifter 101 that shifts a phase of a first phase signal of the resolver with a pole at a frequency f 1 lower than the carrier frequency fc, a second phase shifter 102 that shifts a phase of a second phase signal of the resolver with a pole at a frequency f 2 higher than the carrier frequency fc, and a synthesizer 103 that combines the phase-shifted first phase signal with the phase-shifted second phase signal.

First claim

What is claimed is:

1. A signal converter comprising:
an excitation circuit that generates a carrier signal having a carrier frequency to output the carrier signal to a rotation angle sensor;
a first phase shifter circuit that receives a first phase signal from the rotation angle sensor and shifts a phase of the first phase signal with a pole at a first frequency lower than the carrier frequency;
a second phase shifter circuit that receives a second phase signal from the rotation angle sensor and shifts a phase of the second phase signal with a pole at a second frequency higher than the carrier frequency; and
a synthesizer circuit that combines the phase-shifted first phase signal with the phase-shifted second phase signal and outputs a phase-modulated signal where the carrier signal is phase-modulated by a rotation angle of the rotation angle sensor.

2. The signal converter according to claim 1 , wherein each of the first phase shifter circuit and the second phase shifter circuit comprises an all-pass filter.

3. The signal converter according to claim 1 , wherein the first frequency is one Nth of the carrier frequency and the second frequency is N times of the carrier frequency (N is an arbitrary positive real number).

4. The signal converter according to claim 1 , wherein a difference between a first phase shifted by the first phase shifter circuit and a second phase shifted by the second phase shifter circuit is roughly 90°.

5. The signal converter according to claim 1 , further comprising:
a band-pass filter that attenuates, for the phase-modulated signal, a signal component outside a predetermined frequency range centered on the carrier frequency.

6. The signal converter according to claim 1 , further comprising:
a signal generator that generates a correction signal for cancelling out a ripple component caused by the carrier signal,
wherein the synthesizer superposes the correction signal on the phase-modulated signal.

7. The signal converter according to claim 1 , further comprising:
a synchronization circuit that synchronously wave-detects the phase-modulated signal at the carrier frequency fc and outputs a synchronously wave-detected signal;
a speed ripple calculator that calculates a ripple component based on a differential value of the synchronously wave-detected signal from the synchronization circuit; and
a carrier amplitude phase correction unit that generates a correction signal with a phase and an amplitude by which the ripple component is minimized,
wherein the synthesizer superposes the correction signal on the phase-modulated signal.

8. A signal converter comprising:
an excitation circuit that generates a carrier signal having a carrier frequency to output the carrier signal to a rotation angle sensor:
a first phase shifter circuit that shifts a phase of the first combined signal based on a first and second phase signal from the rotation angle sensor with a pole at a first frequency lower than the carrier frequency;
a second phase shifter circuit that shifts a phase of the second combined signal based on a third and a fourth phase signal from the rotation angle sensor with a pole at a second frequency higher than the carrier frequency; and
a synthesizer circuit that combines the phase-shifted first combined signal with the phase-shifted second combined signal and outputs a phase-modulated signal where the carrier signal is phase-modulated by a rotation angle of the rotation angle sensor,
wherein the first and the second phase signals have phases different from each other by roughly 180°,
wherein the third and the fourth phase signals have phases different from each other by roughly 180°, and
wherein the first and the third phase signals have phases different from each other by roughly 90°.

9. A control device for a motor, comprising:
an excitation circuit that generates a carrier signal having a carrier frequency to output the carrier signal to a rotation angle sensor:
a first phase shifter circuit that receives a first phase signal from the rotation angle sensor and shifts a phase of the first phase signal with a pole at a first frequency lower than the carrier frequency;
a second phase shifter circuit that receives a second phase signal from the rotation angle sensor and shifts a phase of the second phase signal with a pole a second frequency higher than the carrier frequency;
a synthesizer circuit that combines the phase-shifted first phase signal with the phase-shifted second phase signal and outputs a phase-modulated signal where the carrier signal is phase-modulated by a rotation angle of the rotation angle sensor;
a synchronization circuit that synchronously wave-detects the phase-modulated signal at the carrier frequency fc and outputs a synchronously wave-detected signal; and
a controller that controls the motor based on the synchronously wave-detected signal.

10. The control device according to claim 9 , wherein
the first phase shifter circuit shifts a phase of a first combined signal based on the first phase signal and a third phase signal from the rotation angle sensor, the first and the third phase signals having phases different from each other by roughly 180°, and
the second phase shifter circuit shifts a phase of a second combined signal based on the second signal and a fourth signal from the rotation angle sensor, the second and the fourth phase signals having phases different from each other by roughly 180°.

11. The control device according to claim 9 , further comprising:
a signal generator that generates a correction signal for cancelling out a ripple component causes by the carrier signal,
wherein the synthesizer superposes the correction signal on the phase-modulated signal.

Assignees

• Renesas Electronics Corp

Inventors

• Shimizu Yuji
• Hiroshima Akane
• Ono Yutaka

Classifications

• H04L27/20 Primary

  Modulator circuits; Transmitter circuits · CPC title

• H04L7/0008

  Synchronisation information channels, e.g. clock distribution lines · CPC title

• G01D5/245 Primary

  using a variable number of pulses in a train · CPC title

• H04L27/2053 Primary

  using more than one carrier, e.g. carriers with different phases · CPC title