Patent ID: 11949341
Assignee: TOSHIBA MITSUBISHI—ELECTRIC INDUSTRIAL SYSTEMS CORPORATION
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H | IPC H

Claim 0:
1. A power converter comprising:
a diode converter that rectifies an alternating current from a power supply;
an inverter which is formed such that a DC side is connected to a DC output of the diode converter and an AC side is connected to an electric motor and includes a semiconductor switching element converting DC power on the DC side into AC power and a reverse connection diode connected in antiparallel with the semiconductor switching element;
a smoothing capacitor that is provided in the DC output of the diode converter;
a resistor that is connected in parallel with the smoothing capacitor;
a current sensor that detects a load current flowing between the inverter and the electric motor;
an estimation unit that calculates an estimation value of a DC voltage Vdc on the DC side on the basis of a current value I detected by the current sensor; and
a control unit that controls the inverter so that the estimation value of the DC voltage Vdc on the DC side does not exceed a predetermined reference voltage during a period in which the electric motor is in a regenerative state,
wherein the estimation unit calculates the estimation value of the DC voltage Vdc on the DC side on the basis of at least the reference voltage on the DC side, the current value I of the current detected by the current sensor and flowing from the electric motor to the inverter, and a capacity C of the smoothing capacitor, and
wherein the control unit controls a change in the DC voltage Vdc on the basis of the calculated estimation value of the DC voltage Vdc on the DC side.