Operating method for an electric energy system of a motor vehicle comprising a fuel cell system, an accumulator and an electric motor

US9688160B2 · kind B2 · utility

Assignee

• Bayerische Motoren Werke Aktiengesellschaft · DE

Inventors

• Georg Goetz · Taufkirchen, DE
• Sylvester BURCKHARDT · Kirchseeon, DE
• Michael Bauer · Unterföhring, DE
• Andreas Buchner · Zürich, CH
• Florian Pfattrisch · Geretsried, DE

Key dates

• Filing date: Mar 25, 2014
• Grant date: Jun 27, 2017
• Expiry date: Oct 11, 2035

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02T90/40
• WIPO field: Electrical machinery, apparatus, energy
• WIPO sector: Electrical engineering

Abstract

A method of operating an electric system of a motor vehicle, consisting of a fuel cell system, an accumulator and an electric driving motor is provided. Without implementing an electric voltage conversion and therefore without an electric voltage converter, as a function of the level of the electric voltage made available by the fuel cell system and by the accumulator and the electric power demanded by the electric motor, a first switching element in the connection between the fuel cell system and a node point electrically connected with the accumulator and the electric motor, as well as a second switching element in the connection between the accumulator and this node point are opened or closed as needed. This is done such that the power requirement of the electric motor is met primarily from the fuel cell system, and in an auxiliary fashion, additionally from the accumulator. If the electric power offered by the fuel cell system exceeds the electric power demanded by the electric motor, the excess power will be fed to the accumulator for as long as its permissible charging current is not exceeded and the accumulator still has a defined residual storage capacity.