Abb Industry Oy

Samuli Heikkil&auml;

Petri Schroderus

Mikko Norrkniivil&auml;

A method for controlling an inverter which comprises the switching components to be controlled, the method comprising the steps of determining a current vector ({overscore (i)},) for the inverter output; determining a flux vector ({overscore (&psgr;)}) for the inverter load; determining an angular speed (&ohgr;) for the inverter load; determining a resistance (R) for the inverter load. The method further comprises the steps of determining a voltage vector ({overscore (b)}) as a sum of the product of the inverter load resistance (R) and the output current vector ({overscore (i)},) and a voltage proportional to the electromotive force of the load; forming a direction vector ({overscore (S)}) on the basis of a current vector ({overscore (i)},) for the inverter reference value and the inverter output current vector ({overscore (i)},); determining a space coordinate system &mgr;&ugr; associated with the voltage vector ({overscore (b)}) and having a real axis &mgr; which is co-directional with the voltage vector ({overscore (b)}); determining the direction vector ({overscore (S)}) in the &mgr;&ngr; coordinates system; and forming inverter switch commands on the basis of a component ({overscore (S)},) co-directional with the &mgr; axis of the direction vector ({overscore (S)}) and a component ({overscore (S)},) co-directional with the &ugr; axis.

Method for controlling an inverter

A method of defining an instantaneous value of a current (i,e) of a pulse-controlled inductive load when the impedance of the load is known, the method comprising the steps of: measuring the output voltage (u,) of a pulsed voltage source, and measuring the output current (i,) of the pulsed voltage source. The method is characterized by further comprising the steps of: low-pass filtering the measured output current (i,) of the pulsed voltage source to produce a fundamental wave current (i,lp), defining a load current estimate (i,est) by computation on the basis of the measured output voltage (u,) of the pulsed voltage source and the impedance of the load, high-pass filtering the load current estimate (i,est), and defining the instantaneous value of the load current (i,e) by adding the high-pass-filtered load current estimate (i,hp) to the fundamental wave current (i,p).

Growing community of inventors

Helsinki, Finland

Samuli Heikkilä

Growing community of inventors

Helsinki, Finland

Samuli Heikkil&auml;

Samuli Heikkilä