You can add minutes to datetime following way.ACX_Base::getServerDateTime() method is used to get server current date time and addminutes is a method of datetimeutil class.
info(strfmt("%1",DateTimeUtil::addMinutes(ACX_Base::getServerDateTime(), 540)));
info(strfmt("%1",DateTimeUtil::addMinutes(ACX_Base::getServerDateTime(), 540)));