US 12,255,551 B2
Power conversion device and metal processing device
Mizuki Nakahara, Tokyo (JP); Hirooki Tokoi, Tokyo (JP); and Kenji Ikeda, Tokyo (JP)
Assigned to Hitachi Industrial Equipment Systems Co., Ltd., Tokyo (JP)
Appl. No. 18/010,851
Filed by Hitachi Industrial Equipment Systems Co., Ltd., Tokyo (JP)
PCT Filed May 27, 2021, PCT No. PCT/JP2021/020293
§ 371(c)(1), (2) Date Dec. 16, 2022,
PCT Pub. No. WO2022/030082, PCT Pub. Date Feb. 10, 2022.
Claims priority of application No. 2020-131332 (JP), filed on Aug. 3, 2020.
Prior Publication US 2023/0238897 A1, Jul. 27, 2023
Int. Cl. H02M 3/158 (2006.01); H02M 5/458 (2006.01); H02M 7/06 (2006.01); H02M 7/5387 (2007.01); H02P 27/08 (2006.01)
CPC H02M 7/53871 (2013.01) [H02M 3/158 (2013.01); H02M 5/458 (2013.01); H02M 7/06 (2013.01); H02P 27/08 (2013.01)] 9 Claims
OG exemplary drawing
 
1. A power conversion device that supplies power to a motor, the power conversion device comprising:
a converter configured to convert an AC voltage from outside into a DC voltage;
a converter controller configured to control the converter,
wherein the converter includes a voltage doubler circuit configured to boost the DC voltage when activated, and outputs the DC voltage having a voltage value different in accordance with activation and stop of the voltage doubler circuit, and
wherein the converter controller activates the voltage doubler circuit at a first time that is earlier by a predetermined period than a second time at which a speed command value of the motor rises from a predetermined value;
an inverter including a plurality of switching elements and configured to convert the DC voltage from the converter into an AC voltage and output the AC voltage to the motor; and
an inverter controller configured to perform switching control of the plurality of switching elements in the inverter such that a rotation speed of the motor approaches the speed command value;
wherein the converter includes:
a first three-phase diode bridge;
a first DC link capacitor and a second DC link capacitor connected in series between a positive electrode output node and a negative electrode output node of the first three-phase diode bridge; and
a second three-phase diode bridge, a first switching element, a second switching element, and an inductor that constitute the voltage doubler circuit,
wherein the inductor is connected between a common connection node of the first DC link capacitor and the second DC link capacitor and a switch node,
wherein the first switching element is connected between a positive electrode output node of the second three-phase diode bridge and the switch node,
wherein the second switching element is connected between a negative electrode output node of the second three-phase diode bridge and the switch node, and
wherein the converter controller performs switching control of the first switching element and the second switching element in accordance with activation of the voltage doubler circuit.