# US 10,312,800 B2 · AC-DC converter

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- Number: US 10,312,800 B2
- Document ID: US10312800B2
- Status: Granted
- Kind: B2
- Application number: 16/123,282
- Filed: 2018-09-06
- Published: 2019-04-04
- Granted: 2019-06-04
- Earliest claimed: 2017-10-04
- Assignees: Fuji Electric Co., Ltd.
- Applicants: Fuji Electric Co., Ltd.
- Inventors: Ryuji Yamada
- Web page: https://patentgrep.com/patent/US10312800B2

## CPC

- G05F 1/70: Regulating power factor; Regulating reactive current or power
- H02M 1/4225: {using a non-isolated boost converter}
- 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
- 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
- G05F: SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES
- 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)
- 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 a rectified voltage of an AC power supply AC to a DC output voltage by switching ON and OFF a switching device and controls the switching device by using a command value for and a detected value of the DC output voltage as well as a detected value of a reactor current includes: a current sense resistor and a low-pass filter for detecting a rectified current; a proportional controller that multiplies the detected value of the rectified current by a prescribed gain; an output voltage command calculator such as a divider that calculates an output voltage command for the switching device on the basis of an output of the proportional controller; and a circuit that compares the output voltage command to a carrier signal in order to generate a gate signal for the switching device, wherein the prescribed gain is effectively adjusted on the basis of a difference signal between a command value for and a detected value of the DC output voltage.

## 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 current detector that detects a rectified current flowing through the reactor;
a proportional controller that multiplies the detected value of the rectified current by a prescribed gain;
a voltage regulation unit that receives a detected value of the DC output voltage and a command value and that outputs an amplitude command that represents a difference between the command value and the detected value of the DC output voltage;
an output voltage command calculator that calculates an output voltage command for the semiconductor switching device on the basis of an output of the proportional controller and the amplitude command outputted from the voltage regulation unit; and
a drive signal generator that compares the output voltage command to a carrier signal so as to generate a drive signal for switching the semiconductor switching device ON and OFF,
wherein the voltage regulation unit and the output voltage command calculator together function as a gain controlling unit that adjusts the prescribed gain on the basis of the difference between the command value and the detected value of the DC output voltage.

### Claim 2 (depends on 1)

The AC-DC converter according to claim 1, wherein the semiconductor switching device switches OFF when the output voltage command is greater than the carrier signal.

### Claim 3 (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 outputs a value obtained by subtracting the detected value of the DC output voltage from the command value; and
a voltage regulator connected to an output of the subtractor.

### Claim 4 (depends on 2)

The AC-DC converter according to claim 2,
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 outputs a value obtained by subtracting the detected value of the DC output voltage from the command value; and
a voltage regulator connected to an output of the subtractor.

### Claim 5 (depends on 3)

The AC-DC converter according to claim 3, wherein the output voltage command calculator calculates the output voltage command such that the prescribed gain is effectively reduced as the output of the voltage regulator increases.

### Claim 6 (depends on 4)

The AC-DC converter according to claim 4, wherein the output voltage command calculator calculates the output voltage command such that the prescribed gain is effectively reduced as the output of the voltage regulator increases.

### Claim 7 (depends on 1)

The AC-DC converter according to claim 1, wherein the output voltage command calculator is a divider that divides the output of the proportional controller by the amplitude command outputted from the voltage regulation unit to generate the quotient as the output voltage command for the semiconductor switching device.

### Claim 8 (depends on 1)

The AC-DC converter according to claim 1, wherein the output voltage command calculator includes a subtractor that outputs a differential of a constant value relative to the amplitude command outputted from the voltage regulation unit and a multiplier that multiplies the differential outputted from the subtractor with the output of the proportional controller.

### Claim 9 (depends on 2)

The AC-DC converter according to claim 2, wherein the output voltage command calculator is a divider that divides the output of the proportional controller by the amplitude command outputted from the voltage regulation unit to generate the quotient as the output voltage command for the semiconductor switching device.

### Claim 10 (depends on 2)

The AC-DC converter according to claim 2, wherein the output voltage command calculator includes a subtractor that outputs a differential of a constant value relative to the amplitude command outputted from the voltage regulation unit and a multiplier that multiplies the differential outputted from the subtractor with the output of the proportional controller.

### Claim 11 (depends on 3)

The AC-DC converter according to claim 3, wherein the output voltage command calculator is a divider that divides the output of the proportional controller by the amplitude command outputted from the voltage regulation unit to generate the quotient as the output voltage command for the semiconductor switching device.

### Claim 12 (depends on 3)

The AC-DC converter according to claim 3, wherein the output voltage command calculator includes a subtractor that outputs a differential of a constant value relative to the amplitude command outputted from the voltage regulation unit and a multiplier that multiplies the differential outputted from the subtractor with the output of the proportional controller.

### Claim 13 (depends on 4)

The AC-DC converter according to claim 4, wherein the output voltage command calculator is a divider that divides the output of the proportional controller by the amplitude command outputted from the voltage regulation unit to generate the quotient as the output voltage command for the semiconductor switching device.

### Claim 14 (depends on 4)

The AC-DC converter according to claim 4, wherein the output voltage command calculator includes a subtractor that outputs a differential of a constant value relative to the amplitude command outputted from the voltage regulation unit and a multiplier that multiplies the differential outputted from the subtractor with the output of the proportional controller.

### Claim 15 (depends on 5)

The AC-DC converter according to claim 5, wherein the output voltage command calculator is a divider that divides the output of the proportional controller by the amplitude command outputted from the voltage regulation unit to generate the quotient as the output voltage command for the semiconductor switching device.

### Claim 16 (depends on 5)

The AC-DC converter according to claim 5, wherein the output voltage command calculator includes a subtractor that outputs a differential of a constant value relative to the amplitude command outputted from the voltage regulation unit and a multiplier that multiplies the differential outputted from the subtractor with the output of the proportional controller.

### Claim 17 (depends on 6)

The AC-DC converter according to claim 6, wherein the output voltage command calculator is a divider that divides the output of the proportional controller by the amplitude command outputted from the voltage regulation unit to generate the quotient as the output voltage command for the semiconductor switching device.

### Claim 18 (depends on 6)

The AC-DC converter according to claim 6, wherein the output voltage command calculator includes a subtractor that outputs a differential of a constant value relative to the amplitude command outputted from the voltage regulation unit and a multiplier that multiplies the differential outputted from the subtractor with the output of the proportional controller.

### Claim 19 (depends on 1)

The AC-DC converter according to claim 1, further comprising a low-pass filter between the current detector and the proportional controller so that the rectified current, as averaged over one switching cycle of the semiconductor switching device via the low-pass filter, is inputted to the proportional controller.

### Claim 20 (depends on 3)

The AC-DC converter according to claim 3, further comprising a low-pass filter between the current detector and the proportional controller so that the rectified current, as averaged over one switching cycle of the semiconductor switching device via the low-pass filter, is inputted to the proportional controller.