Patent ID: 11942890
Assignee: RENESAS ELECTRONICS CORPORATION
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H | IPC H

Claim 9:
10. A motor drive system comprising:
a three-phase motor;
an inverter circuit configured to drive the three-phase motor, and comprising output nodes corresponding to each phase of the three-phase motor;
a detection circuit coupled to the output nodes, and configured to detect a voltage generated in the output node of a non-energized phase of the three-phase; and
a controller configured to:
at a time of starting the three-phase motor, causing the inverter circuit to apply a drive voltage to any two phases of the three-phase motor based on an estimated magnetic pole position of a rotor in a stop state; and
estimate a position of the rotor based on a difference voltage between i) a voltage generated in the output node of the non-energized phase during a drive voltage applying period and ii) a voltage generated in the output node of the non-energized phase during a regeneration period immediately after or immediately before the drive voltage applying period,

wherein, when an absolute value of the difference voltage is less than or equal to a first threshold, the controller switches the phase the drive voltage applying.