Method and related device for estimating two currents flowing simultaneously through respective windings of a poly-phase electrical load driven in SVM mode

摘要

A method, implemented by circuital means in a device, for estimating at a certain instant two currents of a poly-phase electric load controlled in SVM mode, for example a three-phase electric motor, using the same measuring instrument, without introducing in the measurement error contributory terms due to the inevitable time lag between the two measurements carried out at different instants, comprises the steps of measuring the current flowing in one of the two windings exactly at the desired instant, measuring the current flowing in the other winding first with a certain anticipation in respect to the desired instant and after with a delay equal to the anticipation in respect to the desired instant. The estimated value of the current in the second winding is given in first approximation by the arithmetic mean of the two measured values before and after the desired instant of simultaneous measurement of the two currents.;Therefore, the two currents can be measured with an undecremented precision using the same A/D converter connected through a multiplexer by performing the three closely sequenced sensing of electric current.