METHOD TO CONTROL AC TRACTION DRIVE Russian patent published in 2008 - IPC B60L15/00 

FIELD: transport engineering; electric drives.

SUBSTANCE: invention relates to power converting facilities and it can be used in ac electric drives. Traction drive of electric vehicle has at least one three-phase electric motor designed for constant consumption of power higher than preset frequency of rotation and supplied by two-link ac converter with variable voltage of dc intermediate link. Power is supplied to two-link ac converter power supply system. Voltage of dc intermediate link within the range of frequency of rotation lower than preset value is reduced relative to maximum value so that voltage of dc intermediate link does not drop below some minimum value defined by system voltage in process of operation. Within the range of frequency of rotation higher than preset frequency value, basing on indicated reduced voltage of dc intermediate link, transfer to maximum voltage for said intermediate link at maximum frequency of rotation, depending on frequency of rotation takes place. Control of voltage of dc intermediate link is provided depending on load voltage.

EFFECT: reduced requirements to resources of control system of ac traction drive owing to use of more simple and distinct criteria of optimum operation.

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