# US 2022/0045641 A1 · Power conversion apparatus, drive control system, machine learning apparatus, and motor monitoring method

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 2022/0045641 A1
- Document ID: US20220045641A1
- Status: Published application
- Kind: A1
- Application number: 17/429,635
- Filed: 2019-11-21
- Published: 2022-02-10
- Earliest claimed: 2019-03-18
- Assignees: Mitsubishi Electric Corporation
- Applicants: Mitsubishi Electric Corporation
- Inventors: Norikazu HATTORI; Norihiro SUZUKI; Tetsuo TANAKA; Naoto NORINA; Takahiro HARADA
- Web page: https://patentgrep.com/patent/US20220045641A1

## CPC

- H02P 27/08: with pulse width modulation
- H02H 7/093: against increase beyond, or decrease below, a predetermined level of rotational speed (centrifugal switches H01H35/10)
- H02M 1/0009: {Devices or circuits for detecting current in a converter}
- H02M 5/458: using semiconductor devices only
- H02P 23/0018: {using neural networks}
- H02P 29/024: Detecting a fault condition, e.g. short circuit, locked rotor, open circuit or loss of load
- H02M 1/083: {for the ignition at the zero crossing of the voltage or the current}
- H02P 2205/07: Speed loop, i.e. comparison of the motor speed with a speed reference
- H02P: CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02H: EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS (indicating or signalling undesired working conditions G01R, e.g. G01R31/00, G08B; locating faults along lines G01R31/08; emergency protective devices H01H)
- 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)

## Abstract

A power conversion apparatus includes a main circuit unit, a control unit, a current sensor, and a half-wave rectifier unit. The control unit includes current frequency calculation units and monitoring units. The current frequency calculation units calculate current frequencies based on at least either the rising timing or falling timing of current detection signals half-wave rectified by the half-wave rectifier unit. The monitoring units monitor the speed of a motor based on the current frequencies calculated by the current frequency calculation units.

## Claims

### Claim 1

A power conversion apparatus comprising:
a main circuit to convert DC power into AC power, and supply the converted AC power to a motor;
a controller to control the main circuit;
a current sensor to detect a current supplied from the main circuit to the motor; and
a half-wave rectifier to half-wave rectify a current detection signal output from the current sensor, wherein
the controller includes:
a first processing circuit
to calculate a current frequency based on at least either a rising timing or a falling timing of the current detection signal half-wave rectified by the half-wave rectifier, the current frequency being a frequency of the current; and
to monitor a speed of the motor based on the current frequency calculated.

### Claim 2 (depends on 1)

The power conversion apparatus according to claim 1, further comprising:
a hysteresis comparator to compare, with different threshold values, the rising timing and the falling timing of the current detection signal half-wave rectified by the half-wave rectifier, wherein
the first processing circuit calculates the current frequency based on the rising timing and the falling timing obtained from results of the comparison performed by the hysteresis comparator.

### Claim 3 (depends on 1)

The power conversion apparatus according to claim 1, wherein
the first processing circuit stops power supply from the main circuit to the motor when the current frequency calculated or a value directly proportional to the current frequency exceeds a specified speed limit value.

### Claim 4 (depends on 3)

The power conversion apparatus according to claim 3, further comprising:
a plurality of the first processing circuits, wherein
the first processing circuits stop circuit stops the power supply from the main circuit to the motor when a difference between the current frequencies calculated by the plurality of first processing circuits is outside a preset range.

### Claim 5 (depends on 3)

The power conversion apparatus according to claim 3, further comprising:
a second processing circuit
to generate PWM signals for performing PWM control of the main circuit; and
to calculate an output frequency that is a frequency of an AC voltage output from the main circuit to the motor, wherein
the first processing circuits stop circuit stops the power supply from the main circuit to the motor when a difference between the current frequency calculated and the output frequency calculated by the second processing circuit is outside a preset range.

### Claim 6 (depends on 1)

The power conversion apparatus according to claim 1, wherein
the first processing circuit calculates the current frequency by using a calculation model created by machine learning.

### Claim 7 (depends on 6)

The power conversion apparatus according to claim 6, wherein
the calculation model is created by machine learning based on a signal and a frequency of the current, the signal indicating at least either the rising timing or the falling timing, the frequency of the current being obtained from a measured value, the measured value indicating a waveform of the current or a speed of the motor measured by an external measuring device, and
the first processing circuit causes the calculation model to calculate the current frequency, by inputting the signal indicating at least either the rising timing or the falling timing to the calculation model.

### Claim 8 (depends on 7)

The power conversion apparatus according to claim 7, wherein
the first processing circuit
acquires, as state variables, the signals each indicating at least either the rising timing or the falling timing;
acquires the measured values from the external measuring device, and calculates frequencies of the current based on the measured values acquired; and
creates the calculation model by using machine learning based on a data set created by combinations of the state variables acquired and the frequencies of the current calculated.

### Claim 9 (depends on 7)

A drive control system comprising:
the power conversion apparatus according to claim 7; and
a machine learning apparatus to create the calculation model, wherein
the machine learning apparatus includes:
a third processing circuit
to acquire, as state variables, the signals each indicating at least either the rising timing or the falling timing;
to acquire the measured values from the external measuring device, and calculate frequencies of the current based on the measured values acquired; and
to create the calculation model by machine learning based on a data set created by combinations of the state variables acquired and the frequencies of the current calculated.

### Claim 10

A machine learning apparatus comprising:
a third processing circuit
to acquire, as state variables, signals each indicating at least either a rising timing or a falling timing of a current detection signal, the current detection signal being output from a current sensor and half-wave rectified, the current sensor detecting a current supplied to a motor;
to acquire measured values, and calculate frequencies of the current based on the measured values acquired, the measured values each indicating a waveform of the current or a speed of the motor measured by an external measuring device; and
to create a calculation model by using machine learning based on a data set created by combinations of the state variables acquired and the frequencies of the current calculated.

### Claim 11

A motor monitoring method comprising:
converting DC power into AC power and detecting, with a current sensor, a current supplied from a main circuit to a motor, the main circuit supplying the converted AC power to the motor;
calculating a current frequency based on at least either a rising timing or a falling timing of a current detection signal output from the current sensor and half-wave rectified by a half-wave rectifier, the current frequency being a frequency of the current; and
monitoring a speed of the motor based on the calculated current frequency.