US 12,255,547 B2
Power conversion system
Daiki Mizuguchi, Kariya (JP)
Assigned to KABUSHIKI KAISHA TOYOTA JIDOSHOKKI, Kariya (JP)
Filed by KABUSHIKI KAISHA TOYOTA JIDOSHOKKI, Kariya (JP)
Filed on Mar. 15, 2023, as Appl. No. 18/121,639.
Claims priority of application No. 2022-057050 (JP), filed on Mar. 30, 2022.
Prior Publication US 2023/0318487 A1, Oct. 5, 2023
Int. Cl. H02M 7/537 (2006.01); H02J 7/00 (2006.01); H02M 1/00 (2006.01); H02M 1/38 (2007.01); H02P 27/06 (2006.01)
CPC H02M 7/537 (2013.01) [H02J 7/007 (2013.01); H02M 1/0003 (2021.05); H02M 1/385 (2021.05); H02P 27/06 (2013.01)] 7 Claims
OG exemplary drawing
 
1. A power conversion system comprising:
an inverter that converts electric power between a battery and a motor including three-phase stator coils;
a positive electrode line and a negative electrode line that connect the battery and the inverter to each other;
a smoothing capacitor arranged between the positive electrode line and the negative electrode line; and
a control circuit that controls the inverter, wherein
the inverter includes three-phase switching units connected in parallel to one another between the positive electrode line and the negative electrode line and connected to the respective three-phase stator coils,
each of the three-phase switching units includes
an upper switching element and a lower switching element connected in series in an order from the positive electrode line to the negative electrode line, and
an upper diode and a lower diode connected in anti-parallel to the upper switching element and the lower switching element, respectively,
in release of charges in the smoothing capacitor,
the control circuit
alternately and periodically switches all of the three-phase switching units between all-phase upper on control in which the upper switching element is on and the lower switching element is off and all-phase lower on control in which the upper switching element is off and the lower switching element is on, and
controls, during a period during which switching from one to the other of the all-phase upper on control and the all-phase lower on control is made, states of the upper switching element and lower switching element of each phase as being different from the states in the all-phase upper on control and the all-phase lower on control, and controls, in an initial stage and a final stage of the period during which the switching is made, states of the upper switching element and lower switching element to be set to a state in which both of the upper switching element and lower switching element of at least one phase are off and controls, during a period between the initial stage and the final stage, states of the upper switching element and lower switching element of all phases to be set to an upper on state in which the upper switching element is on and the lower switching element is off or to be set to a lower on state in which the upper switching element is off and the lower switching element is on.