Controller for providing PWM drive to an A.C. motor

• US 4,575,668 A
• Filed: 07/09/1984
• Issued: 03/11/1986
• Est. Priority Date: 07/09/1984
• Status: Expired due to Term

• Current Assignee: Liebert Corporation (Vertiv Holdings Co.)
• Original Assignee: Liebert Corporation (Vertiv Holdings Co.)
• Inventors: Baker, Robert W.
• Primary Examiner(s): Smith, Jr., David
• Application Number:
  US06/629,093
• Time in Patent Office: 610 Days
• Field of Search: 318/811, 323/282-286, 323/901
• US Class Current: 318/811
• CPC Class Codes: H02M 7/53873 with digital control
• CPC Class Codes: H02P 23/0077 Characterised by the use of a particular software algorithm
• CPC Class Codes: H02P 27/08 with pulse width modulation

Abstract

A controller for providing PWM drive to an inductive load incorporating an input rectifier bridge (24) the output of which is filtered by capacitors (106, 108) and which includes input impedance (116, 118) for limiting start-up current surges. A by-pass network (124) controlled from a high voltage sensor circuit (32) controls the by-pass network. The sensor circuit also provides an enablement signal (40) to a pulse width modulation circuit (42). A low voltage power supply (36) is coupled with the output (26) of the rectifier and filter function (24) to supply isolated power to the discrete driver networks of a driver circuit (48). The driver networks are controlled from the pulse width modulation circuit which, in turn, is controlled from a microprocessor (68). The drivers provide drive to three, phase designated transistor pairs of an inverter switching bridge (50) which is supplied power from the rectifier and filter circuit (24).

Claims