Power conversion apparatus

Patent metadata

Field	Value
Publication number	US-2016118904-A1
Application number	US-201514887361-A
Country	US
Kind code	A1
Filing date	Oct 20, 2015
Priority date	Oct 24, 2014
Publication date	Apr 28, 2016
Grant date	—

Abstract

In a power conversion apparatus, an AC/DC conversion circuit part converts AC power supplied from an AC input and output part into DC power. A DC/DC conversion circuit part including a transformer converts the DC power supplied from the AC/DC conversion circuit part into AC power, converts converted AC power into DC power after voltage conversion by the transformer and outputs converted DC power to a DC input and output part. A smoothing capacitor is provided in a connection part between the AC/DC conversion circuit part and the DC/DC conversion circuit part to smooth a voltage at the connection part. A connection switchover part changes a maximum value of the AC voltage at the AC input and output part by switching over a connection state between the AC input and output part and an AC device.

First claim

What is claimed is:

1 . A power conversion apparatus comprising:
an AC input and output part connectable to an AC device, which is either one of an AC power source and an AC load; a DC input and output part connectable to a DC device, which is either one of a DC power source and a DC load; an AC/DC conversion circuit part for converting AC power supplied from the AC input and output part into the DC power; a DC/DC conversion circuit part including a transformer, the DC/DC conversion circuit for converting the DC power supplied from the AC/DC conversion circuit part into AC power, converting converted AC power into DC power after voltage conversion by the transformer and outputting converted DC power to the DC input and output part; a smoothing capacitor provided in a connection part between the AC/DC conversion circuit part and the DC/DC conversion circuit part to smooth a voltage at the connection part; and a connection switchover part for changing a maximum value of the AC voltage at the AC input and output part by switching over a connection state between the AC input and output part and the AC device.

2 . The power conversion apparatus according to claim 1 , wherein:
the connection switchover part is configured to switchover the connection state between the AC input and output part and the AC device so that the maximum value of the AC voltage at the AC input and output part is smaller than an upper limit voltage value, which is calculated by dividing the DC voltage at the DC input and output part by a turn number of a coil of the transformer at a DC input and output part side and multiplying by a turn number of a coil of the transformer at a smoothing capacitor side.

3 . The power conversion apparatus according to claim 1 , wherein:
the connection switchover part is configured to switchover the connection state between the AC input and output part and the AC device so that a difference between the maximum value of the AC voltage at the AC input and output part and an upper limit value is minimized, the upper limit value being calculated by dividing the DC voltage at the DC input and output part by a turn number of a coil of the transformer at a DC input and output part side and multiplying by a turn number of a coil of the transformer at a smoothing capacitor side.

4 . The power conversion apparatus according to claim 2 , wherein:
the AC/DC conversion circuit part or the DC/DC conversion circuit part is configured to perform power conversion so that a voltage ratio between the DC voltage at the DC input and output part and the DC voltage at the smoothing capacitor equals a turn ratio between the turn number of the coil of the transformer at the DC input and output side and the turn number of the coil of the transformer at the smoothing capacitor side.

5 . The power conversion apparatus according to claim 2 , wherein:
two power conversion parts, each of which includes the AC/DC conversion circuit part, the smoothing capacitor and the DC/DC conversion circuit part, are provided in parallel.

6 . The power conversion apparatus according to claim 2 , wherein:
the connection switchover part is configured to switchover the connection states between the AC input and output part and the AC device at a timing when the AC voltage at the AC input output part becomes 0 volt.

7 . The power conversion apparatus according to claim 3 , wherein:
the AC/DC conversion circuit part or the DC/DC conversion circuit part is configured to perform power conversion so that a voltage ratio between the DC voltage at the DC input and output part and the DC voltage at the smoothing capacitor equals a turn ratio between the turn number of the coil of the transformer at the DC input and output side and the turn number of the coil of the transformer at the smoothing capacitor side.

8 . The power conversion apparatus according to claim 3 , wherein:
two power conversion parts, each of which includes the AC/DC conversion circuit part, the smoothing capacitor and the DC/DC conversion circuit part, are provided in parallel.

9 . The power conversion apparatus according to claim 3 , wherein:
the connection switchover part is configured to switchover the connection states between the AC input and output part and the AC device at a timing when the AC voltage at the AC input output part becomes 0 volt.

10 . The power conversion apparatus according to claim 1 , further comprising:
a control part configured to compare the AC voltage at the AC input and output part with a limit voltage value, which is calculated by multiplying the DC voltage at the DC input and output part by a turn ratio between two coils of a transformer provided in the DC/DC conversion circuit part, and control the connection switchover part to switch over the connection states between the AC input and output part and the AC device in accordance with a result of comparison outputted from the control part.

Assignees

• Denso Corp

Inventors

• Yoshikawa Satoru
• Hayashi Yuji
• Fukada Masakazu
• Murakami Tatsuya

Classifications

• H02M7/217

  using semiconductor devices only · CPC title

• H02M7/23 Primary

  arranged for operation in parallel {(H02M7/2176 takes precedence)} · CPC title

• H02M3/33546 Primary

  with automatic control of the output voltage or current (H02M3/33561 takes precedence) · CPC title

• H02M1/007

  Plural converter units in cascade (push-pull DC/DC converters with pre-regulator H02M3/3374; DC-AC converters following a DC-DC stage including a high frequency transformer H02M7/4807; DC-AC converters following a DC-DC conversion stage generating periodically varying voltages H02M7/4826) · CPC title