Power conversion device and power supply system using same

Patent metadata

Field	Value
Publication number	US-10763739-B2
Application number	US-201615575461-A
Country	US
Kind code	B2
Filing date	Apr 27, 2016
Priority date	May 22, 2015
Publication date	Sep 1, 2020
Grant date	Sep 1, 2020

Abstract

A power conversion device includes: a first low voltage side circuit and a first high voltage side circuit which are connected via a first transformer; and a second low voltage side circuit and a second high voltage side circuit which are connected via a second transformer, wherein switching timings of the first high voltage side circuit and the second high voltage side circuit are controlled such that a current difference of an input current to the first low voltage side circuit and an input current to the second low voltage side circuit during a step-up operation becomes smaller than a predetermined value. A driver circuit to output a drive signal of a switching element may be included in at least one of the first low voltage side circuit and the second low voltage side circuit.

First claim

The invention claimed is:

1. A power conversion device comprising:
a first low voltage side circuit and a first high voltage side circuit which are connected via a first transformer;
a second low voltage side circuit and a second high voltage side circuit which are connected via a second transformer; and
a control circuit configured to:
control switching timings of the first high voltage side circuit and the second high voltage side circuit such that a current difference of an input current to the first low voltage side circuit and an input current to the second low voltage side circuit during a step-up operation is reduced and becomes smaller than a predetermined value to balance the input currents, and
control the first high voltage side circuit and the second high voltage side circuit during the step-up operation such that a period for electrically short-circuiting both terminals of any one transformer of the first transformer and the second transformer at the switching timing of the first high voltage side circuit or the second high voltage side circuit is provided.

2. The power conversion device according to claim 1 , wherein
a driver circuit to output a drive signal of a switching element is included in at least one of the first low voltage side circuit and the second low voltage side circuit.

3. The power conversion device according to claim 2 , wherein
the driver circuit to output the drive signal is included in each of the first low voltage side circuit and the second low voltage side circuit, and
the driver circuit outputs the drive signal, on the basis of a control signal common to the first low voltage side circuit and the second low voltage side circuit.

4. The power conversion device according to claim 1 , wherein
at least one of the first high voltage side circuit or the second high voltage side circuit has a first switching leg in which one terminal of the first transformer is connected to a connection point of an upper arm side switching element and a lower arm side switching element and a second switching leg in which the other terminal of the first transformer is connected to a connection point of an upper arm side switching element and a lower arm side switching element, and
the at least one of the first high voltage side circuit or the second high voltage side circuit is controlled such that a period for turning on the upper arm side switching element of the first switching leg and the upper arm side switching element of the second switching leg or turning on the lower arm side switching element of the first switching leg and the lower arm side switching element of the second switching leg is provided.

5. The power conversion device according to claim 1 , wherein
the period is calculated on the basis of the current difference of the input current to the first low voltage side circuit and the input current to the second low voltage side circuit.

6. The power conversion device according to claim 1 , wherein
the first high voltage side circuit is configured using a common switching leg connected to one terminal of the first transformer and connected to one terminal of the second transformer and a first switching leg connected to the other terminal of the first transformer, and
the second high voltage side circuit is configured using the common switching leg and a second switching leg connected to the other terminal of the second transformer.

7. A power supply system comprising:
the power conversion device according to claim 1 ;
a high voltage side battery which is connected to the first high voltage side circuit and the second high voltage side circuit; and
a low voltage side battery which is connected to the first low voltage side circuit and the second low voltage side circuit,
wherein the high voltage side battery is charged with a voltage of the low voltage side battery via the power conversion device.

8. A power supply system comprising:
the power conversion device according to claim 1 ;
a high voltage side battery which is connected to the first high voltage side circuit and the second high voltage side circuit;
a low voltage side battery which is connected to the first low voltage side circuit and the second low voltage side circuit; and
a load which is connected in parallel with the high voltage side battery,
wherein a voltage of the low voltage side battery is supplied to the load via the power conversion device.

9. A power supply system according to claim 7 , wherein
when a capacity of power supplied from the low voltage side battery is smaller than a predetermined value, an operation of any one of the first low voltage side circuit and the second low voltage side circuit is stopped, and
when the capacity of the power supplied from the low voltage side battery is larger than the predetermined value, both the first low voltage side circuit and the second low voltage side circuit are operated.

10. The power conversion device according to claim 1 , wherein
at least one of the first high voltage side circuit or the second high voltage side circuit has a first switching leg in which one terminal of the first transformer is connected to a connection point of an upper arm side switching element and a lower arm side switching element and a second switching leg in which the other terminal of the first transformer is connected to a connection point of an upper arm side switching element and a lower arm side switching element, and
the at least one of the first high voltage side circuit or the second high voltage side circuit is controlled such that a period for turning on the upper arm side switching element of the first switching leg and the upper arm side switching element of the second switching leg or turning on the lower arm side switching element of the first switching leg and the lower arm side switching element of the second switching leg is provided.

11. The power conversion device according to claim 4 , wherein
the period is calculated on the basis of the current difference of the input current to the first low voltage side circuit and the input current to the second low voltage side circuit.

12. The power conversion device according to claim 1 , wherein
the period is calculated on the basis of the current difference of the input current to the first low voltage side circuit and the input current to the second low voltage side circuit.

13. A power supply system comprising:
the power conversion device according to claim 2 ;
a high voltage side battery which is connected to the first high voltage side circuit and the second high voltage side circuit; and
a low voltage side battery which is connected to the first low voltage side circuit and the second low voltage side circuit,
wherein the high voltage side battery is charged with a voltage of the low voltage side battery via the power conversion device.

14. A power supply system comprising:
the power conversion device according to claim 2 ;
a high voltage side battery which is connected to the first high voltage side circuit and the second high voltage side circuit;
a low voltage side battery which is connected to the first low voltage side circuit and the second low voltage side circuit; and
a load which is connected in parallel with the high voltage side battery,
wherein a voltage of the low voltage side battery is supplied to the load via the power conversion device.

15. A power supply system according to claim 8 , wherein
when a capacity of power supplied from the low voltage side battery is smaller than a predetermined value, an operation of any one of the first low voltage side

Assignees

• Hitachi Automotive Systems Ltd

Inventors

• Tanaka Shintaro
• Shimada Takae
• Chida Tadahiko
• Komatsu Mikito

Classifications

• Y02B70/10

  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 · CPC title

• H02M1/0054

  Transistor switching losses (periodically suspending operation of switching converter in low power mode H02M1/0035) · CPC title

• H02J2207/20

  Charging or discharging characterised by the power electronics converter · CPC title

• H02M3/33592

  having a synchronous rectifier circuit or a synchronous freewheeling circuit at the secondary side of an isolation transformer · CPC title

• B60L58/20

  having different nominal voltages · CPC title