US 12,231,065 B2
Position control device
Yoshimasa Egi, Aichi (JP)
Assigned to OKUMA CORPORATION, Aichi (JP)
Filed by OKUMA Corporation, Aichi (JP)
Filed on Oct. 4, 2022, as Appl. No. 17/959,595.
Claims priority of application No. 2021-164477 (JP), filed on Oct. 6, 2021.
Prior Publication US 2023/0107710 A1, Apr. 6, 2023
Int. Cl. H02P 21/00 (2016.01); H02P 21/18 (2016.01); H02P 27/12 (2006.01)
CPC H02P 21/18 (2016.02) [H02P 27/12 (2013.01); H02P 2207/05 (2013.01)] 15 Claims
OG exemplary drawing
 
1. A position control device (1) that controls a rotational speed (ωm) and a rotational angle (θm) of a three-phase synchronous motor (20) by causing a PWM inverter (10) to operate based on a position command value (X) and a detected rotational angle (θm) detected by a position detector (21) that detects the rotational angle (θm) of the three-phase synchronous motor (20), wherein
a processor
converts the detected rotational angle (θm) detected by the position detector (21) into the rotational speed (ωm) of the three-phase synchronous motor (20);
calculates an electrical angle (θ) of the three-phase synchronous motor (20) from the detected rotational angle (θm) detected by the position detector (21);
calculates, based on the position command value (X), a first d-axis current command value (Id1*), a d-axis additional current value (Idc) to be added to the first d-axis current command value (Id1*), and a first q-axis current command value (Iq1*);
calculates a d-axis voltage command value (Vd*) and a q-axis voltage command value (Vq*) from a second d-axis current command value (Id*), which is obtained by adding the d-axis additional current value (Idc) to the first d-axis current command value (Id1*), and the first q-axis current command value (Iq1*);
converts the d-axis voltage command value (Vd*) and the q-axis voltage command value (Vq*) into control voltage command values (Vuo, Vvo, Vwo) of U, V, and W phases; and
inputs the converted control voltage command values (Vuo, Vvo, Vwo) of U, V, and W phases to the PWM inverter (10) to adjust current values (Iu, Iv, Iw) of U, V, and W phases of the three-phase synchronous motor (20), thereby controlling the rotational speed (ωm) and the rotational angle (θm) of the three-phase synchronous motor (20),
wherein
the d-axis additional current value (Idc) oscillates in such a manner that a polarity changes according to the electrical angle (θ) and crosses a zero level with an inclination whose polarity is opposite the polarity of the first q-axis current command value (Iq1*) at a zero-cross electrical angle where U-, V-, and W-phase current values (Iu, Iv, Iw) cross the zero level.