US 11,757,374 B2
Method and apparatus for generating a three-phase voltage
Simon David Hart, Powys (GB); Samuel David Ahearn, Montgomery (GB); Richard Phillips, Banbury (GB); and Tim Woolmer, Waterperry (GB)
Assigned to YASA LIMITED, Kidlington (GB)
Filed by YASA LIMITED, Kidlington (GB)
Filed on Nov. 19, 2021, as Appl. No. 17/531,167.
Claims priority of application No. 2018294 (GB), filed on Nov. 20, 2020.
Prior Publication US 2022/0166346 A1, May 26, 2022
Int. Cl. H02M 7/538 (2007.01); H02M 7/5387 (2007.01); G01R 19/165 (2006.01); H02M 1/15 (2006.01)
CPC H02M 7/53871 (2013.01) [G01R 19/16538 (2013.01); H02M 1/15 (2013.01)] 38 Claims
OG exemplary drawing
1. A method of generating a three-phase output voltage for powering an electrical load, the method comprising:
receiving an input voltage from a voltage source and controlling a controller, using Pulse Width Modulation (PWM) over a plurality of PWM periods, to generate a three phase AC output for an electrical load, each of the plurality of PWM periods comprising one or more switching events, the switching events comprising rising and falling edges between a low voltage and a high voltage to provide ON periods at the high voltage and OFF periods at the low voltage, each of the plurality of PWM periods generating a portion in time of the three phase AC output voltage;
for each respective PWM period:
determine a plurality of switching events for each of the three phases to provide a target output voltage for the respective PWM period; and
compare the switching events across each of the three phases to determine a first time period between a first and second switching event across all of the phases, and a second time period between the second and a third switching event across all of the phases; and
adjusting the timing of one or more switching events in only one of the phases in the respective PWM period in response to the determined first or second time period being greater than a threshold in order to reduce the determined first or second time period.