Automatic calibration of field-oriented elevator motor drive parameters using standstill motor measurements

摘要

An elevator controller (7) is provided with logic (48) which automatically determines field-oriented motor parameters, such as motor time constant (tau R), torque constant (KT*) and a magnetizing current (Id), using only standstill measurements of motor. The method for calculating motor parameters involves: (a) providing a sinusoidal torque current reference signal at a high frequency (FHIGH) high enough such that the motor impedance (ZM) is dominated by the transient inductance (Lsigma ); (b) measuring a feedback torque current (Iq) and a feedback torque voltage (Vq); (c) calculating the transient inductance at the high frequency by the equation: Lsigma = Imag(ZM)atFHIGH/(2pi FHIGH) where ZM=Vq/Iq; (d) providing a sinusoidal torque current reference signal having a variable input frequency; (e) measuring the feedback torque current (Iq) and the feedback torque voltage (Vq); (f) calculating an imaginary part of the rotor impedance Imag(ZR)=Imag(ZM)-omega Lsigma where omega is the input frequency and ZM=Vq/Iq; (g) varying the input frequency and performing steps (d)-(f) to obtain the frequency (FPEAK) at which the maximum value of Imag(ZR) occurs; and (h) calculating the rotor time constant (tau R) based on FPEAK.