Lsis Co., Ltd.

Ls Electric Co., Ltd.

Seung-Cheol Choi

Hak-Jun Lee

An-No Yoo

Anno Yoo

The present disclosure provides an inverter control device for estimating the magnetic flux of a rotor, and calculating and compensating for a slip frequency on the basis of a torque current and a magnetic flux current, to control the speed of an electric motor. To this end, the present invention may comprise: a command voltage generation unit for outputting a three-phase PWM voltage with respect to a command frequency to an inverter on the basis of voltage/frequency operation; and a slip frequency determination unit for determining a slip frequency on the basis of the phase current and phase voltage of an electric motor driven by the inverter.

Inverter control device

The present disclosure provides an inverter control device which estimates back electromotive force of an induction motor, and which uses a torque current and a flux current so as to calculate a slip frequency and compensate for same, thereby enabling the motor to operate at a constant speed. To this end, the present invention may comprise: a command voltage generating unit for outputting, to an inverter, a three phase PWM voltage with respect to a command frequency on the basis of a voltage/frequency operation; and a slip frequency determining unit for determining a slip frequency on the basis of a phase current and a phase voltage of a motor driven by the inverter.

An inverter control device is disclosed. The device is configured: for determining a fundamental-wave magnitude of a phase-voltage corresponding to a modified voltage; for performing a proportional-integral (PI) operation of an error between the fundamental-wave magnitude of the phase-voltage and a magnitude of a reference voltage, and for outputting a compensation voltage; configured for adding the compensation voltage to the reference voltage to obtain an output; and for over-modulating the output and for outputting the over-modulated output as the modified voltage.

An apparatus for controlling an inverter is disclosed. The apparatus for controlling the inverter contained in an inverter system configured to drive a motor determines a slip frequency to be used for compensation of a frequency of a first reference voltage, not only using a first reference voltage (including an amplitude and frequency) of the first reference voltage applied to the inverter, but also using an output current of the motor or a rotor speed of the motor. The apparatus determines not only a frequency of a second reference voltage obtained by compensation of the slip frequency, but also an amplitude of the second reference voltage corresponding to the frequency of the second reference voltage.

Apparatus for controlling inverter

The present disclosure relates to an inverter, and more specifically to an inverter that can be restarted stably by determining whether to restart it when power is supplied after a failure has occurred in the inverter due to a fault in the main supply.

Inverter

The present disclosure relates to a multi-level inverter capable of performing a bypass operation without adding any separate module. The multi-level inverter includes a first capacitor and a second capacitor coupled in series to each other, a plurality switches for generating a multi-level output voltage by using a voltage charged in the first capacitor and the second capacitor and a plurality of diodes respectively coupled in parallel to the plurality of switches, a first output terminal and a second output terminal for outputting the output voltage, and a controller for switching a state of each of the plurality of switches to an on or off state according to one of predetermined bypass modes, thereby interrupting the output of the output voltage through the first output terminal and the second output terminal.

Multi-level inverter

Disclosed herein is an apparatus for controlling an inverter. The apparatus determines the phase of an command voltage in a restart section taking into account the frequency of an input voltage to an electric motor when an input power is reduced below a rated power, the frequency of the input voltage into the electric motor at the time of restarting, a time period for generating a torque, and the phase of the input voltage to the electric motor at the time of the restarting.

Disclosed herein is an apparatus for controlling an inverter in an inverter system. The apparatus includes: a first determining unit to determine a magnitude, a phase and a frequency of an input voltage to an electric motor in the inverter system; and a second determining unit to determine a restart command voltage for generating an inverter driving voltage larger than a residual voltage in the electric motor using the magnitude of the input voltage determined by the first determining unit, when the inverter system is restarted.

Growing community of inventors

Gyeonggi-do, South Korea

Seung-Cheol Choi