US 5,475,292 AGranted

Apparatus for restarting inverter for driving synchronous motor after momentary interruption

AssigneeFuji Electric Co., Ltd.

InventorsTakashi Nakanishi, Shinichi Ishii

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Abstract

An apparatus for restarting an inverter after momentary interruption by detecting a power restoration after a momentary outage of a power supply that supplies power to the inverter for driving a synchronous motor. The apparatus includes a frequency detecting portion that detects the frequency of a terminal voltage of the synchronous motor, a phase difference detector that detects the phase difference between the terminal voltage of the synchronous motor and the output voltage command value of the inverter, a phase controller that performs synchronous control so that the frequency and phase of the output voltage command value of the inverter and those of the terminal voltage of the synchronous motor agree with each other, and a restarting portion that restarts the inverter under the condition that the synchronization has been completed after the power restoration of the power supply. This makes it possible to reduce the restarting time after a momentary interruption of the power supply, and to reduce the rush current at the restarting, and the capacity of the inverter.

Claims5

Dependent claims

An apparatus for restarting an inverter for driving a synchronous motor after momentary interruption, said apparatus restarting the inverter when power supplied to the inverter by a power supply is restored after an interruption, said apparatus comprising:

detecting means for detecting a flux of the synchronous motor as a correlate of a terminal voltage of the synchronous motor and producing a corresponding flux detection value;
frequency detecting means for detecting frequency of the terminal voltage of the synchronous motor, said frequency detecting means comprising a period detector that detects a period of the terminal voltage on the basis of the flux detection value, and a frequency calculator that calculates from the period of the terminal voltage the frequency of the terminal voltage;
phase difference detecting means for detecting phase difference between the terminal voltage of the synchronous motor and an output voltage command value;
means for detecting an interruption of the power supply;
means for performing, during the interruption of the power supply, synchronous control on the basis of output signals of the frequency detecting means and the phase difference detecting means so that the frequency and phase of the output voltage command value and the frequency and phase of the terminal voltage of the synchronous motor agree with each other;
and
means for restarting the inverter under the condition that the synchronization of the synchronous control has been completed after the interruption.

4 more elements

Dependencies are inferred from the claim text.

Facts

Application: 08/097,210Filed 27 Jul 1993
Priority: JP 4-22211428 Jul 1992
Granted: 12 Dec 1995
Term ends: Not estimatedThe source records don’t support an estimate.

Classification5 codes

H02M 1/36
Details of apparatus for conversion: means for starting or stopping converters
H02P 1/52
For starting an individual synchronous motor: by progressive increase of frequency of supply to motor
H02P 29/025
Detecting a fault condition, e.g. short circuit, locked rotor, open circuit or loss of load: the fault being a power interruption
H02M
Apparatus for conversion between ac and ac, between ac and dc, or