A motor control device for a motor includes: an inverter circuit supplying power of a battery to the motor; an inverter input voltage detector detecting an inverter input voltage; and a controller including a drive controller for the motor and an abnormality determination unit for determining power feeding abnormality. The abnormality determination unit determines the power feeding abnormality when the inverter input voltage is lower than a voltage threshold and a current from the battery to the inverter circuit is in a determinable range. The abnormality determination unit determines, based on a motor current electrically conducted to the motor or a rotational speed of the motor, whether the current is in the determinable range. A determination threshold in accordance with the determinable range is set that the inverter input voltage is equal to or higher than the voltage threshold when the power feeding region is normal.

An inverter device that includes an inverter circuit that converts power between DC power and multi-phase AC power; a drive circuit that transfers a drive signal to each of a plurality of switching elements that form the inverter circuit to cause a switching element of the plurality of switching elements to perform turn-on, in which the switching element is caused to transition from an off state to an on state, and turn-off, in which the switching element is caused to transition from the on state to the off state; and a current detection circuit that detects a current that flows through each of the plurality of switching elements.

A monitoring system for an electric power-assisted steering system comprising a DC power supply; an inverter bridge including a plurality of bridge switches selectively connecting phases of a multi-phase electric motor to the DC power supply, the multi-phase electric motor being configured to provide power-assistance to a steering system of a vehicle; a bridge driver circuit for providing control signals to the inverter bridge; and a DC link capacitor circuit interposed between the DC power supply and the inverter bridge, the DC link capacitor circuit at least one DC link capacitor. The monitoring system comprises a monitoring circuit configured to monitor the integrity of the DC link capacitor circuit, and outputting a ripple value indicative of a ripple voltage in an output of the DC power supply; and comparison means for comparing the ripple value with at least one ripple parameter indicative of a fault in the DC link capacitor circuit and determining whether a fault is present.

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 method and a device for bringing a textile machine to a controlled standstill in the event of a failure of the power supply, and a correspondingly equipped textile machine, the textile machine having at least two axes that are driven in synchronization by respective electric motors (M1-M.sub.5) connected to a common intermediate voltage circuit (1), and in which at least one electric motor acting as power generator can supply electric power to at least one other electric motor via the common DC bus (1), and in which the voltage (V) on the common DC bus is controlled by varying at least two variables in such a way that the voltage follows a previously defined curve while the textile machine is being brought to a standstill.

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.

An apparatus for controlling a rotary electric machine includes: first and second inverters corresponding to first and second winding groups; first and second voltage detectors; and first and second control units. Each of the first and second inverters includes plurality of switching elements. The first and second voltage detectors each detects input voltage of corresponding inverter. The first control unit limits a first current command value of the first winding group, when both of the first and second inverter input voltages are in normal, and a first differential value is larger than a determination threshold, and the second control unit limits a second current command value of the second winding group, when both of the first and second inverter input voltages are normal, and a second differential value is larger than the determination threshold.

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.

Power conversion systems and methods are provided for ride through of abnormal grid conditions or disturbances, in which a system rectifier is operated in a first mode to regulate a DC voltage of an intermediate DC circuit, an inverter is operated in the first mode to convert DC power from the intermediate DC circuit to provide AC output power to drive a load. In response to detecting an abnormal grid condition, the system changes to a second mode in which the rectifier is turned off and the inverter regulates the DC voltage of the intermediate DC circuit using power from the load.

A motor control circuit controls an operation of a motor based on an input voltage and a control parameter. A voltage-abnormality detection unit detects abnormality of the input voltage by comparing the input voltage with an allowable voltage range. A memory stores therein a plurality of allowable voltage range candidates made to correspond to a plurality of reference voltages and a plurality of control parameter candidates made to correspond to the plurality of reference voltages. A reference-voltage acquisition unit acquires reference voltage information specifying one of the plurality of reference voltages. A selector selects one of the plurality of allowable voltage range candidates from the plurality of allowable voltage range candidates, corresponding to the one reference voltage, as the allowable voltage range and one of the plurality of control parameter candidates from the plurality of control parameter candidates, corresponding to the one reference voltage, as the control parameter based on the reference voltage information.