公开(公告)号：US3555437A

公开(公告)日：1971-01-12

申请号：US3555437D

申请日：1968-12-26

Applicant: ASEA AB

Inventor： PERSSON ERIK ,  GOLIATH KARL GUNNAR

IPC: G05F1/46 ,  H02M1/14 ,  H02M3/135 ,  H02P7/29 ,  H03B1/04

CPC classification number: H02M1/14 ,  H02P7/29

Abstract: FOR SUPPLYING TO A MOTOR D.C. PULSES WITH A VARIABLE FREQUENCY WHILE SUPPRESSING AN A.C. COMPONENT OF A GIVEN FREQUENCY (F), A SWITCHING DEVICE IS CONNECTED BE TWEEN A SOURCE OF D.C. AND THE MOTOR, WHICH IS RENDERED ALTERNATELY CONDUCTING AND NONCONDUCTING SO AS TO SUPPLY THE MOTOR WITH PULSES IN GROUPS OF N PULSES PER GROUP. THE TIME INTERVAL BETWEEN THE GROUPS CAN BE VARIED, WHILE THE TIME INTERVAL $T BETWEEN SUCCESSIVE PULSES IN EACH GROUP IS KEPT CONSTANT AND EQUAL TO

1

F.N

AS LONG AS THE AVERAGE VALUE OF THE PULSE FREQUENCY IS BELOW THE VALUE AT WHICH THE TIME INTERVAL BETWEEN SUCCESSIVE GROUPS IS LESS THAN $T. AT HIGHER AVERAGE VALUES OF THE PULSE FREQUENCY, UP TO A CERTAIN PRESELECTED VALUE, THE PULSE LENGTH IS KEPT SUBSTANTIALLY CONSTANT, WHILE, IF THE LOAD VOLTAGE IS TO BE INCREASED ABOVE THAT CORRESPONDING TO SUCH PRESELECTED VALUE, THE PULSE LENGTH IS INCREASED WHILE THE PULSE FREQUENCY IS KEPT SUBSTANTIALLY CONSTANT.