# US 11,121,664 B2 · Signal conversion device and motor drive system

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- Number: US 11,121,664 B2
- Document ID: US11121664B2
- Status: Granted
- Kind: B2
- Application number: 16/817,682
- Filed: 2020-03-13
- Published: 2020-10-22
- Granted: 2021-09-14
- Earliest claimed: 2019-04-16
- Assignees: Nidec Servo Corporation
- Applicants: Nidec Servo Corporation
- Inventors: Charles Simson Halason Silitonga
- Web page: https://patentgrep.com/patent/US11121664B2

## CPC

- H02M 7/44: by static converters
- H02P 27/08: with pulse width modulation
- H02M 7/537: using semiconductor devices only, e.g. single switched pulse inverters
- H02P 6/00: Arrangements for controlling synchronous motors or other dynamo-electric motors using electronic commutation dependent on the rotor position; Electronic commutators therefor (vector control H02P21/00)
- H02M 1/0009: {Devices or circuits for detecting current in a converter}
- H02M 7/06: using discharge tubes without control electrode or semiconductor devices without control electrode
- H02M: APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF (transformers H01F; dynamo-electric converters H02K47/00; controlling transformers, reactors or choke coils, control or regulation of electric motors, generators or dynamo-electric converters H02P)
- H02P: CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS

## Abstract

A signal conversion device includes a first signal input terminal, a second signal input terminal, and a detector. A first AC signal is supplied to the first signal input terminal from a signal source. The second signal input terminal is supplied with an in-phase signal that is in phase with the first AC signal and an opposite-phase signal that is opposite in phase with the first AC signal. The second signal input terminal is supplied with a second AC signal whose phase has been switched by a switchover between the in-phase signal and the opposite-phase signal from the signal source. The detector detects, using the supplied first AC signal, whether the supplied second AC signal is the in-phase signal or the opposite-phase signal.

## Claims

### Claim 1

A signal conversion device comprising:
a first signal input terminal to which a first AC signal is supplied from a signal source;
a second signal input terminal including an in-phase signal that is in phase with the first AC signal and an opposite-phase signal that is opposite in phase with the first AC signal, the second signal input terminal is supplied with a second AC signal whose phase has been switched by a switchover between the in-phase signal and the opposite-phase signal from the signal source; and
a detector that detects, using the supplied first AC signal, whether the supplied second AC signal is the in-phase signal or the opposite-phase signal.

### Claim 2 (depends on 1)

The signal conversion device according to claim 1, wherein the detector includes:
a first rectifier circuit that generates a half-wave signal obtained by half-wave rectifying the supplied second AC signal;
a bias circuit that applies a negative bias to the generated half-wave signal during a period in which the supplied first AC signal has a negative amplitude;
a second rectifier circuit that generates a second half-wave signal obtained by half-wave rectifying the biased second AC signal; and
an amplitude detector that detects whether the supplied second AC signal is the in-phase signal or the opposite-phase signal by detecting a positive amplitude of the generated second half-wave signal.

### Claim 3 (depends on 2)

The signal conversion device according to claim 2, wherein the amplitude detector:
includes a smoothing circuit that smooths the generated half-wave signal; and
detects whether the supplied second AC signal is the in-phase signal or the opposite-phase signal by detecting a positive amplitude of the smoothed half-wave signal.

### Claim 4 (depends on 3)

A motor drive system comprising:
a motor main body;
the signal conversion device according to claim 3; and
a drive circuit that controls the motor main body based on
a detection result by the signal conversion device.

### Claim 5 (depends on 2)

A motor drive system comprising:
a motor main body;
the signal conversion device according to claim 2; and
a drive circuit that controls the motor main body based on a detection result by the signal conversion device.

### Claim 6 (depends on 1)

The signal conversion device according to claim 1, wherein the detector includes:
a bias circuit that applies a negative bias to the supplied second AC signal during a period in which the supplied first AC signal has a negative amplitude;
a rectifier circuit that generates a half-wave signal obtained by half-wave rectifying the biased second AC signal; and
an amplitude detector that detects whether the supplied second AC signal is the in-phase signal or the opposite-phase signal by detecting a positive amplitude of the generated half-wave signal.

### Claim 7 (depends on 6)

The signal conversion device according to claim 6, wherein the amplitude detector:
includes a smoothing circuit that smooths the generated half-wave signal; and
detects whether the supplied second AC signal is the in-phase signal or the opposite-phase signal by detecting a positive amplitude of the smoothed half-wave signal.

### Claim 8 (depends on 7)

A motor drive system comprising:
a motor main body;
the signal conversion device according to claim 7; and
a drive circuit that controls the motor main body based on a detection result by the signal conversion device.

### Claim 9 (depends on 6)

A motor drive system comprising:
a motor main body;
the signal conversion device according to claim 6; and
a drive circuit that controls the motor main body based on a detection result by the signal conversion device.

### Claim 10 (depends on 1)

A motor drive system comprising:
a motor main body;
the signal conversion device according to claim 1; and
a drive circuit that controls the motor main body based on a detection result of the signal conversion device.