US 12,244,254 B2
Power conversion device
Masahiro Yamamoto, Osaka (JP); and Masaki Nakaishi, Osaka (JP)
Assigned to DAIKIN INDUSTRIES, LTD., Osaka (JP)
Filed by DAIKIN INDUSTRIES, LTD., Osaka (JP)
Filed on May 5, 2023, as Appl. No. 18/143,890.
Application 18/143,890 is a continuation of application No. PCT/JP2021/041610, filed on Nov. 11, 2021.
Claims priority of application No. 2020-188082 (JP), filed on Nov. 11, 2020.
Prior Publication US 2023/0275533 A1, Aug. 31, 2023
Int. Cl. H02P 27/06 (2006.01); H02K 7/09 (2006.01); H02K 11/33 (2016.01); H02M 7/04 (2006.01); H02M 7/06 (2006.01); H02M 7/537 (2006.01); H02P 6/182 (2016.01)
CPC H02P 27/06 (2013.01) [H02K 7/09 (2013.01); H02K 11/33 (2016.01); H02M 7/05 (2021.05); H02M 7/06 (2013.01); H02M 7/537 (2013.01); H02P 6/182 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A power conversion device configured to rotationally drive a drive shaft of a motor and supply power to support coils that support the drive shaft in a non contact manner by an electromagnetic force, the power conversion device comprising:
a converter circuit configured to
convert a first alternating current from an AC power source into a direct current and
output the direct current to a pair of wires;
an inverter circuit including a switching element, the inverter being configured to
convert the direct current outputted from the converter circuit to the pair of wires into a second alternating current by a switching operation of the switching element and
supply the second alternating current to drive coils of the motor so that the drive shaft is rotationally driven;
a first capacitor connected between the pair of wires;
a buffer circuit including a second capacitor and a regulator connected in series with the second capacitor, the buffer circuit being connected between the pair of wires; and
a current supply circuit configured to supply a current to the support coils using energy stored in the second capacitor so that a load of the drive shaft is supported in a non contact manner,
the first capacitor being configured to
allow pulsation of a voltage outputted from the converter circuit and
absorb voltage variation between the pair of wires caused by the switching operation, and
the regulator being configured to regulate a current flowing from the second capacitor to the first capacitor so that
the current flowing from the second capacitor to the first capacitor when the second capacitor has a higher voltage than the first capacitor by a predetermined voltage difference is smaller than
a current flowing from the first capacitor to the second capacitor when the first capacitor has a higher voltage than the second capacitor by the predetermined voltage difference.