# US 10,374,513 B2 · AC-DC converter

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- Number: US 10,374,513 B2
- Document ID: US10374513B2
- Status: Granted
- Kind: B2
- Application number: 16/056,168
- Filed: 2018-08-06
- Published: 2019-03-28
- Granted: 2019-08-06
- Earliest claimed: 2017-09-27
- Assignees: Fuji Electric Co., Ltd.
- Applicants: Fuji Electric Co., Ltd.
- Inventors: Ryuji Yamada
- Web page: https://patentgrep.com/patent/US10374513B2

## CPC

- H02M 1/4225: {using a non-isolated boost converter}
- H02H 7/125: for rectifiers
- H02M 1/4258: {using a single converter stage both for correction of AC input power factor and generation of a regulated and galvanically isolated DC output voltage (H02M1/4241 takes precedence)}
- H02M 3/156: with automatic control of output voltage or current, e.g. switching regulators
- H02M 7/25: arranged for operation in series, e.g. for multiplication of voltage
- H03K 17/082: by feedback from the output to the control circuit
- H02M 1/0003: {Details of control, feedback or regulation circuits}
- Y02B 70/10: Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes
- Y02P 80/10: Efficient use of energy, e.g. using compressed air or pressurized fluid as energy carrier
- 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)
- 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)
- H03K: PULSE TECHNIQUE (measuring pulse characteristics G01R; modulating sinusoidal oscillations with pulses H03C; transmission of digital information H04L; discriminator circuits detecting phase difference between two signals by counting or integrating cycles of oscillation H03D3/04; automatic control, starting, synchronisation or stabilisation of generators of electronic oscillations or pulses where the type of generator is irrelevant or unspecified H03L; coding, decoding or code conversion, in general H03M)
- Y02B: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS

## Abstract

An AC-DC converter that converts an AC power supply voltage to a DC output voltage of a prescribed magnitude with power factor regulation includes a voltage regulation unit; an instantaneous value command calculator; a current regulation unit; an output voltage command calculator; a drive signal generator that generates a drive signal for a semiconductor switching device from the output voltage command and a carrier signal, the driving signal being provided to the semiconductor switching device so as to switch the semiconductor switching device ON and OFF; and a rectified voltage estimation unit that that derives an estimated value of a rectified voltage obtained by rectifying the AC power supply voltage from the output voltage command without actually detecting a rectified voltage, for providing to the instantaneous value command calculator and the output voltage command calculator.

## Claims

### Claim 1

An AC-DC converter that converts an AC power supply voltage to a DC output voltage of a prescribed magnitude with power factor regulation, comprising:
a rectifying circuit that rectifies the AC power supply voltage to output a rectified voltage;
a reactor that receives the rectified voltage;
a semiconductor switching device connected in series to the reactor;
a voltage regulation unit that receives a detected value of the DC output voltage and a command value and that outputs an amplitude command for the rectified current that represents a difference between the detected value of the DC output voltage and the command value;
an instantaneous value command calculator that receives the amplitude command from the voltage regulation unit and an estimated value of the rectified voltage that is obtained without actually detecting the rectified voltage and that calculates an instantaneous value command for the rectified current from the amplitude command and the estimated value of the rectified voltage;
a current regulation unit that receives the instantaneous value command from the instantaneous value command calculator and a detected value of a rectified current flowing through the reactor and that outputs a signal representing a difference between the instantaneous value command and the detected value of the rectified current;
an output voltage command calculator that receives the signal outputted from the current regulation unit and the estimated value of the rectified voltage and that calculates an output voltage command for the semiconductor switching device from the signal outputted from the current regulation unit and the estimated value of the rectified voltage;
a drive signal generator that receives the output voltage command from the output voltage command calculator and a carrier signal and that generates a drive signal for the semiconductor switching device from the output voltage command and the carrier signal, the driving signal being provided to the semiconductor switching device so as to switch the semiconductor switching device ON and OFF; and
a rectified voltage estimation unit that receives the output voltage command from the output voltage command calculator and that derives the estimated value of the rectified voltage from the output voltage command without actually detecting the rectified voltage, for providing to the instantaneous value command calculator and the output voltage command calculator.

### Claim 2 (depends on 1)

The AC-DC converter according to claim 1, wherein the rectified voltage estimation unit derives the estimated value of the rectified voltage using a duty cycle of the semiconductor switching device.

### Claim 3 (depends on 1)

The AC-DC converter according to claim 1, wherein the rectified voltage estimation unit derives the estimated value of the rectified voltage using OFF time ratio of the semiconductor switching device.

### Claim 4 (depends on 1)

The AC-DC converter according to claim 1, wherein the rectified voltage estimation unit derives the estimated value of the rectified voltage by calculating an average value of the output voltage command over one switching cycle of the semiconductor switching device.

### Claim 5 (depends on 1)

The AC-DC converter according to claim 1, wherein the rectified voltage estimation unit derives the estimated value of the rectified voltage by removing high-frequency ripple components from the output voltage command.

### Claim 6 (depends on 1)

The AC-DC converter according to claim 1, wherein the rectified voltage estimation unit includes a low-pass filter or a band-pass filter.

### Claim 7 (depends on 1)

The AC-DC converter according to claim 1,
wherein the voltage regulation unit includes:
a subtractor that receives the detected value of the DC output voltage and the command value as inputs; and
a voltage regulator connected to an output of the subtractor.

### Claim 8 (depends on 1)

The AC-DC converter according to claim 1,
wherein the current regulation unit includes:
a subtractor that receives the instantaneous value command and the detected value of the rectified current as inputs; and
a current regulator connected to an output of the subtractor.

### Claim 9 (depends on 1)

The AC-DC converter according to claim 1,
wherein the instantaneous value command calculator is a multiplier that multiplies the amplitude command by the estimated value of the rectified voltage to generate the instantaneous value command.

### Claim 10 (depends on 1)

The AC-DC converter according to claim 1,
wherein the output voltage command calculator is a subtractor that receives the signal outputted from the current regulation unit and the estimated value of the rectified voltage and that outputs a difference between the signal outputted from the current regulation unit and the estimated value of the rectified voltage as the output voltage command.

### Claim 11 (depends on 1)

The AC-DC converter according to claim 1,
wherein the rectified voltage estimation unit includes:
a first low-pass filter that receives the output voltage command from the output voltage command calculator, an output of the first low-pass filter being provided to the output voltage command calculator as the estimated value of the rectified voltage to be used in the output voltage command calculator; and
a second low-pass filter that receives the output of the first low-pass filter, an output of the second low-pass filter being provided to the instantaneous value command calculator as the estimated value of the rectified voltage to be used in the instantaneous value command calculator.

### Claim 12 (depends on 1)

The AC-DC converter according to claim 1,
wherein the voltage regulation unit includes:
a subtractor that receives the detected value of the DC output voltage and the command value as inputs; and
a voltage regulator connected to an output of the subtractor,
wherein the current regulation unit includes:
a subtractor that receives the instantaneous value command and the detected value of the rectified current as inputs; and
a current regulator connected to an output of the subtractor,
wherein the instantaneous value command calculator is a multiplier that multiplies the amplitude command by the estimated value of the rectified voltage to generate the instantaneous value command, and
wherein the output voltage command calculator is a subtractor that receives the signal outputted from the current regulation unit and the estimated value of the rectified voltage and that outputs a difference between the signal outputted from the current regulation unit and the estimated value of the rectified voltage as the output voltage command.