James C Gary

US Patent:

46396659, Jan 27, 1987

Filed:

Aug 22, 1983

Appl. No.:

6/525520

Inventors:

James R. Gary - Elk Grove Village IL

Assignee:

Borg-Warner Corporation - Chicago IL

International Classification:

G01R 3300
G01R 1900

US Classification:

324117H

Abstract:

A parameter, such as the current flowing through a conductor, is measured by initially passing an energizing magnetic flux through a hall element to produce a hall voltage proportional to the sensed parameter. To eliminate temperature, aging and non-linear effects normally associated with a hall element, the amplitude of the hall voltage is effectively ignored and only its polarity is detected and employed to control the operation of an integrator to develop a cancelling current to establish an equal, but opposite direction, cancelling flux in the hall element. With a zero net flux, the integrator will hold the cancelling current at the level required to balance out and cancel the initial energizing flux. Since the cancelling current needed to null the energizing flux will be proportional to that flux, the current may be used to produce a control voltage to represent the measured parameter.

US Patent:

45659575, Jan 21, 1986

Filed:

Jun 30, 1983

Appl. No.:

6/509625

Inventors:

James R. Gary - Elk Grove Village IL
Everett R. Geis - Orange CA
Todd L. King - Buffalo Grove IL
Daljit Singh - Elk Grove Village IL

Assignee:

Borg-Warner Corporation - Chicago IL

International Classification:

H02P 540

US Classification:

318723

Abstract:

Highly reliable and consistent starting is achieved by first initializing the rotor position, namely establishing the rotor in a known starting position. This is accomplished by gating on two pairs of SCRs in sequence and supplying current pulses through the gated SCRs to the stator of the motor to rotate the rotor to a first position and then to a second position, the rotor coming to a complete stop in each of those positions. The rotor aligns itself with the magnetic field created by the stator in each position and any ambiguity in the rotor position is eliminated. Thereafter, the inverter is operated asynchronously in a second mode with predetermined pairs of the inverter SCRs being sequentially gated into conduction at an increasing frequency to current pulse energize the motor to effect step-by-step rotation of the rotor at a faster and faster rate, the motor current being reduced to zero at the termination of each energizing pulse to force commutate the conducting pair of SCRs. After the motor has reached a preset speed, operation in a third mode occurs and the inverter is synchronized with the motor, gating of the SCRs being controlled by the motor voltage in order that the rotor position will be synchronized to the revolving magnetic field created by the stator. During this third operating mode the motor speed continues to increase and the SCRs are forced commutated, as a result of which the rotor follows the stator magnetic field very closely and synchronization will be perfected.