Power conversion apparatus and method for starting up the same

Patent metadata

Field	Value
Publication number	US-9793791-B2
Application number	US-201514641834-A
Country	US
Kind code	B2
Filing date	Mar 9, 2015
Priority date	Mar 11, 2014
Publication date	Oct 17, 2017
Grant date	Oct 17, 2017

Abstract

A power conversion apparatus includes a transformer; a primary side full bridge circuit provided on a primary side of the transformer; a first port connected to the primary side full bridge circuit; a second port connected to a center tap of the primary side of the transformer; a secondary side full bridge circuit provided on a secondary side of the transformer; a third port connected to the secondary side full bridge circuit; and a control unit configured to cause an upper arm of the secondary side full bridge circuit to operate in an active region in a case where a capacitor connected to the third port is charged with a transmitted power transmitted to the secondary side full bridge circuit via the transformer from the primary side full bridge circuit when power of the second port is stepped up and the stepped up power is output to the first port.

First claim

What is claimed is:

1. A power conversion apparatus comprising:
a transformer;
a primary side full bridge circuit that is provided on a primary side of the transformer;
a first port that is connected to the primary side full bridge circuit;
a second port that is connected to a center tap of the primary side of the transformer;
a secondary side full bridge circuit that is provided on a secondary side of the transformer;
a third port that is connected to the secondary side full bridge circuit; and
a control unit that is programmed to cause a first switching element in an upper arm of the secondary side full bridge circuit to operate in an active region throughout a period when a capacitor that is connected to the third port is charged with a transmitted power that is transmitted to the secondary side full bridge circuit via the transformer from the primary side full bridge circuit when a power of the second port is stepped up and the stepped up power is output to the first port.

2. The power conversion apparatus according to claim 1 , wherein the control unit is programmed to gradually increase a duty ratio of time for which the first switching element operates in the active region, and to charge the capacitor that is connected to the third port with the transmitted power.

3. The power conversion apparatus according to claim 1 , wherein
the first switching element has a first diode provided in parallel with a direction for charging the capacitor as a forward direction and the upper arm of the second side full bridge circuit further includes a second switching element having a second diode provided in parallel with a direction opposite to the direction of the first diode as a forward direction are connected in series, and
the control unit is programmed to cause the second switching element to operate in the active region, and to charge the capacitor that is connected to the third port with the transmitted power.

4. The power conversion apparatus according to claim 1 , wherein the control unit is programmed to allow a power to be input from the third port when a voltage of the capacitor that is connected to the third port is equal to or greater than a predetermined value.

5. The power conversion apparatus according to claim 1 , further comprising a fourth port that is connected to a center tap of the secondary side of the transformer, wherein
the control unit is programmed to charge a capacitor that is connected to the fourth port with the transmitted power.

6. The power conversion apparatus according to claim 5 , wherein the control unit is programmed to cause a third switching element of a lower arm of the secondary side full bridge circuit to operate in the active region when the capacitor that is connected to the fourth port is charged with the transmitted power.

7. The power conversion apparatus according to claim 6 , wherein the control unit is programmed to gradually increase a duty ratio of time for which the the third switching element operates in the active region, and to charge the capacitor that is connected to the fourth port with the transmitted power.

8. The power conversion apparatus according to claim 6 , wherein
the third switching element has a third diode provided in parallel with a direction for charging the capacitor as a forward direction and the lower arm of the secondary side full bridge circuit further includes a fourth switching element having a fourth diode provided in parallel with a direction opposite to the direction of the third diode as a forward direction are connected in series, and
the control unit is programmed to cause the fourth switching element to operate in the active region, and to charge the capacitor that is connected to the fourth port with the transmitted power.

9. The power conversion apparatus according to claim 5 , wherein the control unit is programmed to allow a power to be input from the fourth port when a voltage of the capacitor that is connected to the fourth port is equal to or greater than a predetermined value.

10. The power conversion apparatus according to claim 1 , wherein the control unit is programmed to cause a fifth switching element of an upper arm of the primary side full bridge circuit to operate in the active region when a capacitor that is connected to the first port is charged by a power supply that is connected to the second port via the center tap of the primary side.

11. The power conversion apparatus according to claim 10 , wherein the control unit is programmed to gradually increase a voltage of the capacitor that is connected to the first port with the stepped up power from detecting that the voltage of the capacitor that is connected to the first port is equal to or greater than a first threshold value until detecting that the voltage of the capacitor that is connected to the first port is equal to or greater than a second threshold value that is greater than the first threshold value.

12. The power conversion apparatus according to claim 11 , wherein the control unit is programmed to gradually increase a duty ratio of time for which an arm of the primary side full bridge circuit is turned on, and to charge the capacitor that is connected to the first port with the stepped up power.

13. The power conversion apparatus according to claim 1 , wherein the control unit is programmed to charge the capacitor that is connected to the third port with the transmitted power that is transmitted during a period of gradually increasing a voltage of the first port with the stepped up power.

14. The power conversion apparatus according to claim 1 , wherein the control unit is programmed to interrupt, according to current or temperature of an arm of the primary side full bridge circuit or current or temperature of an arm of the secondary side full bridge circuit, an operation of a switching element corresponding to the arm in the active region.

15. The power conversion apparatus according to claim 1 , wherein
the active region is an operation region in which the first switching element is conductive with a predetermined resistance value RT or more when a gate voltage of the first switching element is within a range in which it is equal to or higher than a gate threshold voltage and is equal to or lower than a predetermined voltage value Vth, and
the predetermined voltage value Vth is a voltage value that is lower than the gate voltage in a steady state after starting up of the power supply apparatus is completed.

16. A method for starting up a power conversion apparatus, which includes a transformer; a primary side full bridge circuit that is provided on a primary side of the transformer; a first port that is connected to the primary side full bridge circuit; a second port that is connected to a center tap of the primary side of the transformer; a secondary side full bridge circuit that is provided on a secondary side of the transformer; and a third port that is connected to the secondary side full bridge circuit, the method for starting up the power conversion apparatus comprising:
causing a switching element in an upper arm of the secondary side full bridge circuit to operate in an active region throughout a period when a capacitor that is connected to the third port is charged with a transmitted power that is transmitted to the secondary side full bridge circuit via the transformer from the primary side full bridge circuit when a power of the second port is stepped up and the stepped up power is output to the first port.

Assignees

• Toyota Motor Co Ltd

Inventors

• Shono Shoichi
• Uchihara Masafumi
• Hasegawa Naoto
• Miura Mitsuhiro
• Tanahashi Fumiki
• Muto Jun

Classifications

• H02M1/36 Primary

  Means for starting or stopping converters · CPC title

• H02M3/33561

  having more than one ouput with independent control · CPC title

• H02M3/33584

  Bidirectional converters · CPC title

• Y02T10/72

  Electric energy management in electromobility · CPC title

• B60L2240/525

  Temperature of converter or components thereof · CPC title