Abb Schweiz Ag

Yang Gao

Fawei Zhang

Tao Li

Chunping Zhang

Controller device

Controller

A method for controlling an electric motor, the method including determining a planned reference speed of the electric motor; determining a pulse-width modulation (PWM) switching frequency based on the planned reference speed; and controlling the electric motor with an alternating current produced by PWM switching with the determined PWM switching frequency. A control system for controlling an electric motor and an industrial robot including a control system, are also provided.

Method and control system for controlling an electric motor

Robot controller

A method of controlling a drive including one respective inverter associated with each of a plurality of servomotors in a robot. The method includes providing a PWM frequency corresponding to a frequency of switching instances for respective semiconductor switches in each of the inverters, whereby for each inverter time is divided into consecutive control cycles forming a sequence of control cycles of the inverter, each control cycle containing two, and only two, of the switching instances for each of the semiconductor switches. The method also includes spreading the respective control cycle sequences of the inverters over time such that the control cycles of each inverter are time shifted in respect to the control cycles of each of the other inverters in the power converter.

Time-spread control cycles for robotic servomotors

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Västerås, Sweden

Yang Gao