Monitoring system for use in electric system to monitor electrical motor of e.g. electric car, has module for measuring voltage of neutral point of machine, and unit for processing filtered voltage to detect malfunctions of machine

摘要

The system (DCO) has a measurement module (MTE) for measuring voltage of a neutral point of a polyphase electric machine (MEL). Filtering units (MFN) filter the measured voltage. A processing unit (MTT) processes the filtered voltage to detect malfunctions of the machine. The filtering units preserve a component of voltage at the neutral point in the filtered voltage at piloting frequency of the machine. The system varies cutoff frequency of the filter units such that the cut-off frequency is greater than or equal to the piloting frequency of the machine. Independent claims are also included for the following: (1) a method for controlling operation of a polyphase electric machine powered by a battery whose current is corrugated by an inverter (2) an electric system.