Electronically commutatable motor

US6351091B1 · kind B1 · utility

Assignee

• Robert Bosch GmbH · DE

Inventors

• Hans-Martin Heinkel · Stuttgart, DE
• Gerhard Knecht · Iffezheim, DE
• Rainer Berger · Remscheid, DE

Key dates

• Filing date: Jul 21, 2000
• Grant date: Feb 26, 2002
• Expiry date: Jul 21, 2020

Classification

• Technology area (CPC H): Electricity
• CPC primary: H02P6/30
• WIPO field: Electrical machinery, apparatus, energy
• WIPO sector: Electrical engineering

Abstract

An electronically commutable motor, whose excitation windings can be fed with current via semiconductor output stages from an electronic control unit using pulse-width modulated control signals and, in this context, which generate a rotating field in the stator of the motor, the rotating field placing the permanent magnet of the motor in rotational motion. Without position sensors, a reliable start-up in the rotational direction is achieved even given a high mass moment of inertia, a small cogging inertia, and poor damping such that, during the start-up of the motor, the control unit, during a specific or specifiable start-up phase, drives the semiconductor output stages in overlapping control phases using PWM control signals, whose pulse-width ratio rises from a minimum to a maximum and then falls again to the minimum, that the overlapping areas of the control phases in the affected excitation windings generate currents which yield a virtually continuous torque curve, and that, in the start-up phase, by shortening the commutation time between the control phases, coming after one another, the commutation frequency and thus the rotational speed of the motor is increased.