Patent ID: 11962259
Assignee: CITY UNIVERSITY OF HONG KONG
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H | IPC H

Claim 0:
1. A method of controlling a drive system for an N phase permanent magnet synchronous motor, the motor comprising a rotor and a stator, the rotor comprising at least one permanent magnet and the stator comprising N windings, wherein N is an integer greater than 2, each winding comprising first and second ends;
the drive system comprising:
first and second power rails;
a DC power supply of voltage Vdc connected between the first and second power rails;
N bridge arms connected in parallel between the first and second power rails, each bridge arm comprising first and second switches connected in series;
N output lines, each output line being connected between a first end of a winding and a bridge arm at a point between the first and second switches; each output line being connected to a different winding and a different half bridge arm;

the method comprising the steps of for each of a plurality of consecutive duty cycles
(a) providing the rate of rotation w of the rotor and a reference rate of rotation wref to a PI controller, the output of the PI controller being the q axis reference current iqref;
(b) providing iqref and a measured q axis current iq to a PI controller, the output of the PI controller being the q axis reference voltage Uqref;
(c) providing a d axis reference current idref and a measured d axis current id to a PI controller, the output of the PI controller being the d axis reference voltage Udref;
(d) determining from a look up table the switch pattern for the next duty cycle, the output of the look up table being dependent upon Uqref and Udref; and;
(e) setting the switches of the drive system at the end of the duty cycle to the determined switch pattern for the next duty cycle.