Abstract: 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.

Abstract: An apparatus for controlling an induction motor is provided, the apparatus generates generating a d-axis current command and a q-axis current command of a torque command, estimating speed of a rotor of the motor, and correcting the d-axis and q-axis current commands by using the estimated speed, to enhances the rotor speed and position estimation performance by increasing the slip frequency.

Abstract: An apparatus for determining start of electric machine is disclosed wherein a frequency of a 3-phase current inputted from a motor is estimated to determine whether the motor has started using a difference between the estimated frequency and a frequency of output voltage of inverter configured to drive the motor.

Abstract: An apparatus for controlling an induction motor is provided, the apparatus generates generating a d-axis current command and a q-axis current command of a torque command, estimating speed of a rotor of the motor, and correcting the d-axis and q-axis current commands by using the estimated speed, to enhances the rotor speed and position estimation performance by increasing the slip frequency.

Abstract: Provided is an energy storage system including: a battery device that is configured from multiple battery unit modules; and a power converting system that is configured to be connected to the battery device and that converts electric power that is applied between an electric power system and the battery device, in which the battery device includes multiple switches, each of which establishes a connection between each of the battery unit modules and the power converting system.

Abstract: A phase compensation apparatus in an inverter output voltage in a system is provided, whereby performance of an inverter can be enhanced by compensating a time delay of measured voltage of inverter output voltage detection unit.

Abstract: Disclosed embodiments relate to methods, apparatuses, and systems for estimating parameters of an induction machine. In some embodiments, a method for estimating parameter of an induction machine includes estimating parameters of the induction machine more accurately even when it is stationary by utilizing voltage equations of the induction machine and signal processing techniques, with no additional hardware.

Abstract: Disclosed embodiments relate to apparatuses, methods, and systems for restarting an induction machine. In some embodiments, a method includes estimating a position of a rotor and a speed thereof in a position and speed estimation Operation, resetting a speed reference to correspond to the speed of the rotor in a speed reference resetting Operation, generating a control voltage corresponding to the speed reference to regulate a voltage magnitude using the control voltage in a voltage magnitude regulation Operation, and re-accelerating the induction machine up to a target speed after the regulation of the voltage magnitude in a re-acceleration Operation.

Abstract: Disclosed embodiments relate to a control method of an energy management and more particularly, to an energy management system which is capable of reflecting a state of each energy storage system in the energy management system.

Abstract: Disclosed herein is a capacitance estimation apparatus of a DC-link capacitance in an inverter. The apparatus according to the present invention may estimate a DC-link voltage, and compare it with a ripple size of the measured DC-link voltage to estimate a DC-link capacitance. According to the present invention, the capacitance of the DC-link capacitance contained in the inverter may be estimated in real time to detect the fault status in real time.

Abstract: Some embodiments include an electric power conversion apparatus, which may include a transformer, a first converter connected to a primary side of the transformer, a second converter connected to a secondary side of the transformer, a first capacitor connected to the first converter, a second capacitor connected to the second converter, and a control unit for controlling the first converter and the second converter, wherein the control unit may determine operation ranges with respect to a plurality of modulation methods, may determine a modulation method including an output electric power value of the electric power conversion apparatus among the operation ranges of the plurality of modulation methods, and may output control signals of the first converter and the second converter based on the determined modulation method, wherein the control signals correspond to an instruction value.

Abstract: In some embodiments, a system of controlling an induction electric motor, includes a command voltage output unit for generating a command voltage for operating an inverter according to a command speed and outputting the generated command voltage to the inverter; a control unit for controlling the command voltage output unit such that the command voltage output to the inverter is compared with an operation limiting voltage and the command voltage is corrected to fall within the operation limiting voltage; and the inverter for controlling the induction electric motor depending on the corrected command voltage. Thus, it is possible to precisely control the induction electric motor even in a high speed operation region by regulating the magnitude of the command voltage applied to the induction electric motor by means of dynamic modulation strategies without the magnetic flux controller.

Abstract: An inverter system is provided. In the inverter system according to the present disclosure, adjacently arranged four switching elements among U phase and V phase switching elements configured in an NPC/H bridge manner are converted to an ON state to bypass a voltage applied from a DC link capacitor.

Abstract: A multilevel inverter having a configuration adequate to enhance efficiency while reducing conduction loss is disclosed, the multilevel inverter including a rectifier, a smoothing unit and an inverter unit, wherein the inverter unit includes a first switch unit interposed between the first node and a first output terminal, second switch units interposed between the second node and the first output terminal, a third switch unit interposed between the third node and the first output terminal, a fourth switch unit interposed between the first node and a second output terminal, fifth switch units interposed between the second node and the second output terminal and a sixth switch unit interposed between the third node and the second output terminal.

Abstract: A sensor-less vector control apparatus for induction motor enhanced in performance of sensor-less vector control by estimating changes in parameters in real time is provided, the apparatus including a current controller, a first phase converting unit, a second phase converting unit, a rotor speed and position estimator configured to measure a rotor speed of a rotor and a rotor flux using an output value of the first phase converting unit and to estimate a rotor position using the output value, and a stator resistance and angle error estimator configured to calculate a stator resistance and an angle error of the induction motor by receiving d, q axis current commands on the synchronous reference frame inputted from the current controller and d, q voltages on the synchronous reference frame outputted from the current controller, and to provide the stator resistance to the rotor speed and position estimator.

Abstract: The disclosure relates to an electric power conversion apparatus, and capable of determining a minimum output voltage of a boost converter based on a voltage of the grid, and comparing the minimum output voltage of the converter with an input voltage of the converter, and controlling the operation of the converter based on the comparison result, thereby reducing the unnecessary operation and switching loss of the converter, the electric power conversion apparatus according to the invention comprises a converter; and a control unit configured to detect a grid voltage to determine a minimum output voltage of the converter based on the grid voltage, and control the operation of the converter based on an input voltage of the converter and the determined minimum output voltage.

Abstract: An apparatus for controlling an induction machine is disclosed, wherein a magnitude of a current outputted to the induction machine to an inverter is determined by the apparatus to determine a voltage amount that compensates the command voltage in response to the magnitude of the current, and a voltage compensation amount is added to a command voltage determined from a voltage-frequency relationship according to a relevant voltage compensation amount to output a final command voltage.

Abstract: A multilevel inverter having an efficient structure is provided, the multilevel inverter including a modularized phase-shift transformer including a plurality of modules to provide a phase shifted voltage by receiving a 3-phase input voltage, a plurality of first group unit power cells configured to provide an output voltage of predetermined phase, a plurality of second group unit power cells configured to provide an output voltage of predetermined phase, a plurality of third group unit power cells configured to provide an output voltage of predetermined phase. One of the first group unit power cells, one of the second group unit power cells and one of the third group unit power cells are paired to provide an output voltage of same phase.

Abstract: A multi-level inverter includes: a rectifying unit to rectify received a three-phase voltage; a smoothing unit to receive the rectified voltage and provide the rectified voltage as voltages having different levels to first to third different nodes; and an inverter unit including a plurality of switch units to transfer the voltages having three levels provided from the smoothing unit, wherein the inverter unit includes a first switch unit provided between the first node and a first output terminal, a second switch unit provided between the second node and the first output terminal, a third switch unit provided between the third node and the first output terminal, a fourth switch unit provided between the first node and a second output terminal, a fifth switch unit provided between the second node and the second output terminal, and a sixth switch unit provided between the third node and the second output terminal.

Abstract: A multi-level medium-voltage inverter that receives three-phase power and outputs a three-phase voltage to a three-phase motor, includes: a plurality of unit power cells connected in series to output a single phase voltage, individual unit power cells each having a phase voltage forming a single level to configure multiple levels; and a module-type phase shift transformer configured to convert the three-phase power and applying the converted power to three unit power cells constituting one level, wherein the module-type phase shift transformer includes a plurality of modules.