Power conversion device and metal processing device

A metal processing device that processes a metal as a workpiece by a press mechanism, the metal processing device comprising:

• a motor configured to control a position of the press mechanism between a processing position when the metal is processed and a predetermined standby position;
• and
• a power conversion device configured to supply power to the motor,
• wherein the power conversion device includes:
• 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,
• wherein the second time is a time at which transfer of the press mechanism from the processing position to the standby position is started,
• wherein the power conversion device further includes:
• 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 or a current value of the motor approaches a current 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.