DRIVE CONTROL APPARATUS OF MOTOR

摘要

Previously, the average of a neutral voltage is detected through a low-pass filter with a pass band lower than the PWM frequency, and any abnormality such as grounding is detected by comparing the value with a certain threshold value. Since harmonic waves which are dependent on a modulation signal are overlapped on the neutral voltage, the characteristic of the low pass filter needs to set a time constant corresponding to all of the output frequency bands of an inverter and also needs to separate voltage variation by the modulation signal and voltage variation due to grounding. Abnormality in an output line is determined based on the actual neutral voltage of a motor variable in steps based on the PWM pulse pattern of the inverter and based on the regular neutral voltage decided based on the PWM pattern of the inverter so that abnormality in the output line such as grounding can be determined. It is possible to detect abnormality reliably through neutral voltage waveforms and at the same time stably regardless of inverter output frequencies. [Reference numerals] (210) Current controller;(220) PWM generator;(230) Abnormality determiner;(AA) Control command;(BB) Abnormal signal (lamp on)