Power supply apparatus and image forming apparatus

Patent metadata

Field	Value
Publication number	US-10069435-B2
Application number	US-201715845255-A
Country	US
Kind code	B2
Filing date	Dec 18, 2017
Priority date	Jan 6, 2017
Publication date	Sep 4, 2018
Grant date	Sep 4, 2018

Abstract

The power supply apparatus configured to supply power to a load includes a control unit that corrects a power amount calculated by a power calculation unit based on a first voltage of an AC power supply calculated by a voltage calculation unit when the power amount is calculated, and a second voltage of the AC power supply calculated by the voltage calculation unit when a switching unit is controlled to start power supply to a power supply and a first transformer from the AC power supply.

First claim

What is claimed is:

1. A power supply apparatus configured to supply power to a load, comprising:
a first line and a second line each of which receives an AC voltage from an AC power supply;
a conversion element configured to convert the AC voltage input to each of the first line and the second line into a current according to the AC voltage;
a voltage detection device including a first transformer including a primary winding and a secondary winding, the voltage detection device configured to detect an AC voltage based on a signal indicating the AC voltage output from the secondary winding of the first transformer by supplying the current converted by the conversion element to the primary winding;
a current detection unit including a second transformer having a primary winding and a secondary winding, the current detection unit configured to detect a current value of a current supplied to a first load included in the load based on a signal indicating an AC voltage output to a secondary side of the second transformer according to the current by supplying the current to the primary winding;
a zero-crossing detection unit configured to detect a zero-crossing timing of the AC power supply based on a signal indicating the AC voltage detected by the voltage detection device;
a voltage calculation unit configured to calculate a voltage of the AC power supply based on the signal indicating the AC voltage detected by the voltage detection device and the zero-crossing timing of the AC power supply detected by the zero-crossing detection unit;
a power calculation unit configured to calculate an amount of power to be supplied to the first load from the AC power supply based on a value of a current to be supplied to the first load detected based on the signal indicating the AC voltage output from the current detection unit, and a voltage value of the AC voltage calculated by the voltage calculation unit;
a switching unit configured to connect or disconnect a current path from the AC power supply to the primary winding of the first transformer and a power supply configured to output a predetermined DC voltage to a second load included in the load; and
a control unit configured to control the switching unit and control power supply to the first load and the second load,
wherein the control unit corrects the amount of power calculated by the power calculation unit based on a first voltage of the AC power supply calculated by the voltage calculation unit when the amount of power is calculated, and a second voltage of the AC power supply calculated by the voltage calculation unit when the switching unit is controlled to start power supply to the power supply and the first transformer from the AC power supply.

2. The power supply apparatus according to claim 1 , comprising a phase adjustment unit provided at a subsequent stage of the voltage detection device, the phase adjustment unit configured to adjust a phase of a signal indicating the AC voltage output from the voltage detection device in such a manner that a phase difference between the signal and a signal indicating an AC voltage of the AC power supply is decreased,
wherein the zero-crossing detection unit detects the zero-crossing timing using a signal indicating the AC voltage having a phase adjusted by the phase adjustment unit, and
wherein the voltage calculation unit calculates a voltage of the AC power supply using the signal indicating the AC voltage having the phase adjusted by the phase adjustment unit.

3. The power supply apparatus according to claim 1 , wherein the control unit does not correct the amount of power when a difference of a voltage value obtained by subtracting the first voltage from the second voltage is larger than a predetermined voltage value.

4. The power supply apparatus according to claim 3 , wherein the predetermined voltage value is determined based on a maximum value of a current to be supplied to the power supply from the AC power supply.

5. The power supply apparatus according to claim 1 , wherein the conversion element comprises a first resistor and a second resistor,
one end of the first resistor is connected to the first line, and another end of the first resistor is connected to one end of the primary winding of the first transformer, and
one end of the second resistor is connected to the second line, and another end of the second resistor is connected to another end of the primary winding of the first transformer.

6. The power supply apparatus according to claim 1 , wherein one end of the first load is connected to the first line and another end of the first load is connected to one end of the primary winding of the second transformer, and
another end of the primary winding is connected to the second line.

7. An image forming apparatus comprising:
an image forming unit configured to form an image on a recording material;
a fixing unit including a heating resistor member, the fixing unit configured to fix an unfixed toner image formed on the recording material onto the recording material;
a power supply unit configured to supply power to the fixing unit,
wherein the power supply unit includes:
a first line and a second line each receiving an AC voltage from an AC power supply;
a conversion element configured to convert the AC voltage input to each of the first line and the second line into a current according to the AC voltage;
a voltage detection device including a first transformer including a primary winding and a secondary winding, the voltage detection device configured to detect an AC voltage based on a signal indicating the AC voltage output from the secondary winding of the first transformer by supplying the current converted by the conversion element to the primary winding;
a current detection unit including a second transformer including a primary winding and a secondary winding, the current detection unit configured to detect a current value of a current supplied to a first load included in the load based on a signal indicating an AC voltage output to a secondary side of the second transformer according to the current by supplying the current to the primary winding;
a zero-crossing detection unit configured to detect a zero-crossing timing of the AC power supply based on a signal indicating the AC voltage detected by the voltage detection device;
a voltage calculation unit configured to calculate a voltage of the AC power supply based on the signal indicating the AC voltage detected by the voltage detection device and the zero-crossing timing of the AC power supply detected by the zero-crossing detection unit;
a power calculation unit configured to calculate an amount of power to be supplied to the first load from the AC power supply based on a value of a current to be supplied to the first load detected based on the signal indicating the AC voltage output from the current detection unit, and a voltage value of the AC voltage calculated by the voltage calculation unit;
a switching unit configured to connect or disconnect a current path from the AC power supply to the primary winding of the first transformer and a power supply configured to output a predetermined DC voltage to a second load included in the load; and
a control unit configured to control the switching unit and control power supply to the first load and the second load, and
wherein the control unit corrects the amount of power calculated by the power calculation unit based on a first voltage of the AC power supply calculated by the voltage calculation unit when the amount of power is calculated, and a second voltage of the AC power supply calculated by the voltage calculation unit when the switching unit is controlled to start power supply to the power supply and the first transformer from the AC powe

Assignees

• Canon Kk

Inventors

• Itoh Masatoshi

Classifications

• G03G15/80

  Details relating to power supplies, circuits boards, electrical connections · CPC title

• H02M7/04 Primary

  by static converters · CPC title