Traveling control apparatus for electric vehicles

• US 6,011,378 A
• Filed: 04/06/1998
• Issued: 01/04/2000
• Est. Priority Date: 09/29/1994
• Status: Expired due to Term

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group), TOYO R & D Company Limited
• Inventors: Tabata, Kunio, Kozaki, Minoru
• Primary Examiner(s): Sircus, Brian
• Application Number:
  US09/056,080
• Time in Patent Office: 638 Days
• Field of Search: 318/362, 318/364-378, 318/259, 318/757, 318/761
• US Class Current: 318/759
• CPC Class Codes: B60L 2200/26 Rail vehicles
• CPC Class Codes: B60L 3/00 Electric devices on electrically-propelled vehicles for safety purposes; Monitoring operating variables, e.g. speed, deceleration or energy consumption methods or circuit arrangements for monitoring or controlling batteries or fuel cells B60L58/00
• CPC Class Codes: B60L 50/60 using power supplied by batteries in combination with fuel cells B60L50/75
• CPC Class Codes: B60L 58/10 for monitoring or controlling batteries
• CPC Class Codes: B60L 7/16 for vehicles comprising converters between the power source and the motor
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

A control apparatus by which a duty ratio in consideration of how energy stored in storage cells is consumed is set to ensure a steady traveling feeling, a regeneration brake which can produce stable braking forces regardless of how storage cells are consumed, and a protective device by which a plurality of operation stop levels are set to be able to cancel the stop operation effected for the first time and to ensure reliable alarming, are provided. In the first and second embodiments, a chopper duty ratio is compensated depending on how storage cells are consumed, to provide a steady agreeable traveling feeling. In the third embodiment, regenerated electric power is consumed by a motor driving circuit to stabilize operation of a regeneration brake regardless of how storage cells are consumed, and improve performance thereof. In the fourth embodiment, in a protective device for determining an operating condition of equipment, issuing an alarm in the event of abnormality, and stopping operation of the equipment, the stop operation is effected in two steps and a cancel switch for canceling the stop operation in the first step is provided to, depending on the situation, cancel the stop operation effected by the protective device.

Claims

1. A regeneration brake for an electric vehicle comprising an electric motor for traveling driven by electric power supplied from storage cells, a motor driving circuit for controllably rotating said electric motor through chopper control, said motor driving circuit comprising at least one transistor having a gate, a source and a drain, and regenerative braking means using said motor as an electric dynamo temporarily while said vehicle is decelerated, for charging said storage cells with regenerated electric power, wherein said regeneration brake comprises:

regeneration determining means for determining whether said storage cells can be charged with the regenerated electric power or not based on the amount of electric power regenerated by said regeneration brake and the amount of electric power chargeable to said storage cells when the regenerative braking operation is effected, and

electric power consuming means for distributing the surplus regenerated electric power to said motor driving circuit based on determination by said regeneration determining means that said storage cells are no more chargeable, so that the surplus regenerated electric power is consumed by said motor driving circuit,

wherein when said storage cells cannot be charged as determined by said regeneration determining means, said at least one transistor is turned on and further a gate voltage applied to said gate is adjusted to change an on-resistance between said source and drain to control the regenerated electric power.

2. A regenerative brake for an electric vehicle having an electric motor, a motor driving circuit for controllably rotating said electric motor through chopper control, said motor driving circuit comprising at least one transistor having a gate, a source and a drain, and at least one storage cell, wherein the storage cell has a capacity for being charged, wherein said electric motor acts as a dynamo when the electric vehicle is decelerated, said regenerative brake comprising:

regenerative determining means for determining if the storage cell is less than the capacity for being charge, wherein when the storage cell is less than the capacity for being charged as determined by said regenerative determining means, the storage cell is charged by said electric motor when said electric motor acts as the dynamo when the electric vehicle is decelerated; and

power consuming means for consuming power produced by said electric motor when said electric motor acts as the dynamo when the electric vehicle is decelerated, when the storage cell exceeds than the capacity for being charged as determined by said regenerative determining means,

wherein when said storage cell cannot be charged as determined by said regeneration determining means, said at least one transistor is turned on and further a gate voltage applied to said gate is adjusted to change an on-resistance between said source and drain to control the regenerated electric power.

3. An electric vehicle comprising:

a motor;

a motor driving circuit for controllably rotating said motor though chopper control, said motor driving circuit comprising at least one transistor having a gate, a source and a chain;

a storage cell for supplying energy to said motor, wherein the storage cell has a capacity for being charged;

a regenerative brake, wherein the motor acts as a dynamo when the electric vehicle is decelerated;

regenerative determining means for determining if the storage cell is less than the capacity for being charge, wherein when the storage cell is less than the capacity for being charged as determined by said regenerative determining means, the storage cell is charged by the motor when the motor acts as the dynamo when the electric vehicle is decelerated; and

power consuming means for consuming power produced by the motor when the motor acts as the dynamo when the electric vehicle is decelerated, when the storage cell exceeds than the capacity for being charged as determined by said regenerative determining means,

wherein when said storage cell cannot be charged as determined by said regeneration determining means, said at least one transistor is turned on and further a gate voltage applied to said gate is adjusted to change an on-resistance between said source and drain to control the regenerated electric power.

4. The electric vehicle according to claim 3, further comprising

a speed input device responsive to an operator of the electric vehicle for inputting a desired speed of the electric vehicle;

and

wherein said motor driving circuit controlls the electric motor by varying a duty ratio of a voltage applied to the motor, wherein said the duty ratio is set in accordance with the desired speed of the electric vehicle and the charge capacity of the vehicle, wherein the voltage is applied t_a time per period of time t, and wherein the duty ratio is defined as a ratio of t_a to t.

5. An electric vehicle comprising:

a motor;

a storage cell for supplying energy to said motor, wherein the storage cell has a capacity for being charged;

a regenerative brake, wherein the motor acts as a dynamo when the electric vehicle is decelerated;

regenerative determining means for determining if the storage cell is less than the capacity for being charge, wherein when the storage cell is less than the capacity for being charged as determined by said regenerative determining means, the storage cell is charged by the motor when the motor acts as the dynamo when the electric vehicle is decelerated; and

a motor driving circuit for controlling said motor, wherein said motor driving circuit comprises power consuming means for consuming power produced by the motor when the motor acts as the dynamo when the electric vehicle is decelerated, when the storage cell exceeds than the capacity for being charged as determined by said regenerative determining means, said motor driving circuit comprising at least one transistor having a gate, a source and a drain,

wherein when said storage cell cannot be charged as determined by said regeneration determining means, said at least one transistor is turned on and further a gate voltage applied to said gate is adjusted to change an on-resistance between said source and drain to control the regenerated electric power.