Hybrid electric vehicle with traction motor drive allocated between battery and auxiliary source depending upon battery charge state

• US 5,929,595 A
• Filed: 03/20/1998
• Issued: 07/27/1999
• Est. Priority Date: 11/21/1997
• Status: Expired due to Term

• Current Assignee: BAE Systems Controls Incorporated (BAE Systems Plc)
• Original Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Inventors: Lyons, Arthur Paull, Grewe, Timothy Michael
• Primary Examiner(s): Tso, Edward H.
• Application Number:
  US09/044,671
• Time in Patent Office: 494 Days
• Field of Search: 320/104, 320/127, 320/132, 320/135, 320/137, 320/138, 320/FOR 156, 320/FOR 160, 320/FOR 171, 320/DIG. 34, 180/65.1, 180/65.3, 180/65.4, 322/14, 322/40, 322/99
• US Class Current: 320/104
• CPC Class Codes: B60K 6/46 Series type
• CPC Class Codes: B60L 50/61 by batteries charged by engine-driven generators, e.g. series hybrid electric vehicles
• CPC Class Codes: B60L 7/14 for vehicles propelled by ac motors
• CPC Class Codes: B60W 10/08 including control of electric propulsion units, e.g. motors or generators
• CPC Class Codes: B60W 10/18 including control of braking systems
• CPC Class Codes: B60W 10/26 for electrical energy, e.g. batteries or capacitors
• CPC Class Codes: B60W 20/00 Control systems specially adapted for hybrid vehicles hybrid vehicle design, B60K6/00; electric vehicles B60L
• CPC Class Codes: B60W 20/13 in order to stay within battery power input or output limits; in order to prevent overcharging or battery depletion
• CPC Class Codes: B64G 1/425 Power storage
• CPC Class Codes: B64G 1/428 Power distribution and management
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 10/72 Electric energy management in electromobility
• CPC Class Codes: Y10S 903/903 having energy storing means, e.g. battery, capacitor
• CPC Class Codes: Y10S 903/947 Characterized by control of braking, e.g. blending of regeneration, friction braking

Abstract

An electric vehicle is controlled to conform its operation to that of a conventional internal-combustion-engine powered vehicle. In some embodiments, the charging of the batteries by the auxiliary source of electricity and from dynamic braking is ramped in magnitude when the batteries lie in a state of charge between partial charge and full charge, with the magnitude of the charging being related to the relative state of charge of the battery. The deficiency between traction motor demand and the energy available from the auxiliary electrical source is provided from the batteries in an amount which depends upon the state of the batteries, so that the full amount of the deficiency is provided when the batteries are near full charge, and little or no energy is provided by the batteries when they are near a discharged condition. At charge states of the batteries between near-full-charge and near-full-discharge, the batteries supply an amount of energy which depends monotonically upon the charge state. Charging of the batteries from the auxiliary source is reduced during dynamic braking when the batteries are near full charge. Control of the amount of energy returned during dynamic braking may be performed by control of the transducing efficiency of the traction motor operated as a generator.

Claims

1. A method for operating a hybrid electric vehicle which derives at least some of its tractive effort from electric batteries, comprising the steps of:

in operating modes of said vehicle other than a braking state, providing energy to a traction motor from an auxiliary source, and also providing the difference between the traction power demand and the supply from the auxiliary source from said batteries, up to the maximum capability of said batteries, when said batteries are in a state of charge lying between a first state of charge and full charge;

in said operating modes of said vehicle other than a braking state, providing energy to said traction motor only from said auxiliary source, when said batteries are in a second charge state, representing a substantially discharged state of said batteries; and

in said operating modes of said vehicle other than a braking state, providing energy to said traction motor from said auxiliary source, and also supplying energy to said traction motor from said batteries in an amount less than the full capability of said batteries, when said batteries are in a state of charge lying between said discharged state and said first state of charge.

2. A method for operating a hybrid electric vehicle which derives at least some of its tractive effort from electric batteries, comprising the steps of:

in operating modes of said vehicle other than a braking state, providing energy to a traction motor from an auxiliary electrical energy source, and also providing from said batteries the difference between the traction power demand and the supply from the auxiliary source, up to the maximum capability of said batteries, when said batteries are in a state of charge lying between full charge and a first state of charge less than full charge;

in said operating modes of said vehicle other than a braking state, providing energy to said traction motor only from said auxiliary source, when said batteries are in a second charge state, representing a substantially discharged state of said batteries; and

in said operating modes of said vehicle other than a braking state, providing energy to said traction motor from said auxiliary source, and also supplying energy to said traction motor from said batteries in an amount which is in roughly in the same proportion to the full capability of said batteries as is the amount of charge in said batteries relative to said full charge.