Patent ID: 8493009

Claim:
Surgical motor control device for controlling a surgical drive unit comprising a sensorless electric motor with M motor windings (R MW — 1 , . . . , R MW — M ), the motor control device being configured to perform a method for controlling the drive unit, and the motor control device being configured to control the drive unit using a multiphase PWM method, the motor control device comprising: a signal generating device with which a PWM signal (S PWM — 1 , . . . , S PWM — M ) is generatable for each of the M motor windings (R MW — 1 , . . . , R MW — M ), and with which each of the M PWM signals (S PMW — 1 , . . . , S PWM — M ) is divisible into N subphase signals (S PWM — 1 , . . . , S PWM — 1 — N ; . . . ; S PWM — M — 1 , . . . , S PWM — M — N ) which are displaced in their phase position relative to one another through 360°/N in each case; and a multiphase transformer, with which the N subphase signals (S PWM — 1 — 1 , . . . , S PWM —1 — N ; . . . ; S PWM — M — 1 , . . . , S PWM — M — N ) associated with a respective one of the M motor windings (R MW — 1 , . . . , R MW — M ) are convertible into N subphase winding voltages (U MW — 1 — 1 , . . . , U MW — 1 — N ; . . . ; U MW — M — 1 , . . . , U MW — M — N ) which are displaced in their phase position relative to one another through 360°/N in each case, with which in order to generate a current flow (I MW — 1 , . . . , I MW — M ) through each of the M motor windings (R MW — 1 , . . . , R MW — M ) a respective winding voltage (U MW — 1 , . . . , U MW — M ) is applied to each of the M motor windings (R MW —1 , . . . , R MW — M ), and with which the N subphase winding voltages (U MW — 1 — 1 , . . . , U MW — 1 — N ; . . . ; U MW — M — N ) associated with a respective one of the M motor windings are separately superimposed for each of the M motor windings (R MW — 1 , . . . , R MW — M ), for formation of the respective winding voltage (U MW — 1 , . . . , U MW — M ) that is directly applied to the respective motor winding (R MW — 1 , . . . , R MW — M ), in order to generate the winding current (I MW —1 , . . . , I MW — M ); wherein a power loss at each motor winding, caused by current ripple, is reduced by a factor of 1/N 2 .