Title:
DIRECT CURRENT COMMAND GENERATION FOR A STEPPER MOTOR DRIVE
Document Type and Number:
WIPO Patent Application WO1999018655
Kind Code:
A9
Abstract:
A system for controlling a stepper motor is disclosed that includes a microprocessor (16) for directly generating current command signals. The microprocessor (16) is of the type having memory (34, 36) wherein the memory includes two transfer tables (34, 36). The microprocessor (16), in accordance with software-selectable current magnitude parameter values and microstepping parameter values, determines a sequence of digital words to populate a first one of the tables (34, 36). The stepper motor is a two-phase motor and the digital words corresponding to the phase current commands are generated by the microprocessor (16) using sine, and cosine law function tables (46, 48). A DMA controller (45) in the microprocessor (16) outputs the populated transfer table to a drive circuit to energize the stepper motor while the main control software executing in the microprocessor (16) populates the second-transfer table (36). Once the first transfer table (34) has been completely output to the drive circuit, the roles of the transfer tables (34, 36) are reversed and the process is repeated.
Inventors:
KOMM WILLIAM
Application Number:
PCT/US1998/020718
Publication Date:
June 24, 1999
Filing Date:
October 02, 1998
Export Citation:
Assignee:
DANA CORP (US)
International Classes:
H02P8/00; H02P8/12; (IPC1-7): H02P8/22
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