A power conversion apparatus having a converter, an inverter controlled by inverter controller, and an input power source fluctuation detecting and controlling circuit is proposed. The input power source fluctuation detecting and controlling circuit includes an input power source fluctuation detector and a converter failure detector to detect overcurrent and/or overvoltage of the converter. When both of the input power source fluctuation and the converter failure are detected, the converter is gate blocked, and the inverter continues its operation, and when the DC voltage become lower than a threshold voltage during the converter is gate blocking, the input power source fluctuation detecting and controlling circuit outputs an inverter control changeover flag to the inverter controller for switching a contents of inverter control.

A method of controlling a motor controller includes receiving respective measurements for each of at least three phase currents or voltages output by the motor controller that were instantaneously sensed at substantially the same instant, determining a magnitude of a model signal that models the sensed phase currents or voltages at the instant of the instantaneous sensing as a function of each of the respective measurements, and controlling the motor controller based on the magnitude of the model signal. A motor controller and a controller of a motor controller using the method are also provided.

A motor drive system includes a MUX circuit, a DC voltage scaling circuit, a fault detection circuit, an ADC, and an FPGA. The MUX circuit selectively establishes a MUX input signal path and a MUX output signal path. The DC voltage scaling circuit measures a DC link voltage. The fault detection circuit receives the output DC link voltage and outputs one of a normal operation signal or a fault signal in response to comparing the DC link voltage to one or both of a U/V reference voltage and an O/V reference voltage. The ADC converts one or more input analog voltages into respective corresponding output digital voltages. The FPGA is in signal communication with the ADC output (ADC.sub.OUT) and the MUX circuit, and is configured to control the motor drive system based on a comparison between one or more of the output digital voltages.

A method for determining a resonance frequency of a mechanical system including an electric motor coupled to a mechanical load. The method includes starting the motor by providing a supply voltage using a motor controller, and once the electric motor is running at a predefined target rotational speed, applying a first excitation signal comprising a voltage pulse superimposed to the supply voltage. The method further includes measuring a mechanical response of the mechanical system, using a measurement system coupled to the motor, and analyzing the measured response, to determine at least one resonance frequency of the mechanical system.

A method for detecting a stall condition of an electric motor. The method can include initiating an open-loop phase. During the open-loop phase, the method can include increasing a rotational speed of an electric motor and obtaining data indicative of a voltage associated with the electric motor while increasing the rotational speed of the electric motor. During the open-loop phase, the method can also include determining a difference between the voltage and a time varying target voltage and detecting a stall condition based at least in part on the difference between the voltage and the time varying target voltage. When a closed-loop condition is satisfied, the method can include initiating a closed-loop phase.

An anomaly diagnosing device diagnoses an anomaly in a single motor driven by multiple motor drive units. The multiple motor drive units supply AC currents to multiple multi-phase windings of the motor to drive the motor. The anomaly diagnosing device includes: a power consumption calculator for calculating power consumption in each of the multi-phase windings; a power difference calculator for calculating a difference in power consumption between the multi-phase windings; and a determination unit for determining that an anomaly is occurring when the absolute value of the difference has exceeded a threshold for a predetermined period of time.

A motor drive device includes an inverter that drives a motor, a power source smoothing capacitor of the inverter, and a control unit that controls the inverter to drive the motor. The control unit precharges the capacitor with a power source voltage, and calculates a capacity value of the capacitor, based on a ratio of the power source voltage and a voltage with which the capacitor is charged, or an amount of time taken until the voltage with which the capacitor is charged, after the passage of a predetermined amount of time from the start of the precharge, reaches a voltage corresponding to the power source voltage. The control unit performs torque limitation of the motor when the capacity value of the capacitor has decreased.

This electric compressor control device comprises: a control unit of an inverter which controls a motor that drives a compressor; a physical quantity calculation unit which calculates, on the basis of one or a plurality of predetermined detection values acquired from the inverter, a physical quantity that varies depending on a workload of the compressor; a number-of-revolutions acquisition unit which acquires the number of revolutions of the motor; a storage unit which stores information representing a first threshold that varies depending on the number of revolutions of the motor, and defines whether or not the physical quantity is a normal value; and a refrigerant abnormality determination unit which determines whether or not there is an abnormality in a refrigerant system by comparing the calculated physical quantity with the first threshold, depending on the acquired number of revolutions.

The invention relates to an electric machine tool comprising an electric motor, a motor control unit for operating the electric motor, an input interface for entering a target specification of an operating mode of the electric motor into the motor control unit, and a motor sensor device for detecting the operating mode of the electric motor. A slave control unit is provided, which is independent from the motor control unit and communicatingly connected to the motor sensor device and the input interface and designed to compare the operating mode of the electric motor detected by the motor sensor device with the target specification entered via the input interface, and to influence the operating mode of the electric motor in case of a defined deviation of the operating mode from the target specification by means of a control device.

The present disclosure relates to a drain pump driving apparatus and a laundry treatment machine including the same. A drain pump driving apparatus according to an embodiment of the present disclosure includes: a converter; an inverter to output converted AC voltage to a drain pump motor; an output current detector to detect an output current flowing in the motor; and a controller to control the inverter, wherein in case in which the speed of the motor increases and the output current flowing in the motor decreases during a predetermined period among an operation period of the drain motor, the controller controls the inverter to be turned off. Accordingly, it is possible to protect internal circuit elements in case the motor loses its synchronism.