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

Claim 5:
6. An electric motor braking method using a power converter including: 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 on 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 capcitor; and a current sensor that detects a load current flowing between the inverter and the electric motor, the electric motor braking method comprising:
calculating an estimation value of a DC volatge Vdc on the DC side on the basis of at least a predetermined reference voltage on the DC side, a 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
controlling the inverter so that the estimation value of the DC voltage Vdc on the DC side does not exceed the reference volatge during a period in which the electric motor is in a regenerative state, controlling a change in the DC voltage Vdc on the basis of the calculated estimation value of the DC voltage Vdc on the DC side.