Power steering motor control unit with driving mode correction

• US 5,787,376 A
• Filed: 12/29/1995
• Issued: 07/28/1998
• Est. Priority Date: 09/01/1995
• Status: Expired due to Fees

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Ushio, Masaya, Wada, Shunichi, Nishino, Kazuhisa
• Primary Examiner(s): NGUYEN, TAN QUANG
• Application Number:
  US08/581,208
• Time in Patent Office: 942 Days
• Field of Search: 364/424.051, 364/424.052, 364/424.053, 388/815, 388/811, 388/819, 318/254, 318/432, 318/434, 318/266, 318/282, 318/286, 180/446, 180/443
• US Class Current: 701/41
• CPC Class Codes: B62D 5/046 Controlling the motor
• CPC Class Codes: H02P 7/04 by means of a H-bridge circuit

Abstract

A power steering motor control unit for driving a motor in a PWM mode with feedback motor current control reduces fluctuations in the output torque of the motor caused by switching among a plurality of motor driving modes or a change in the duty value of the PWM signal. The control unit as a switching device driving circuit for driving the motor in the PWM mode and a plurality of motor driving modes for the driving control system of a motor, Q/D switching circuitry 14 for switching the motor driving mode, and detected current correcting circuitry 16 for correcting at least one input signal of an input signal comparing circuit provided in a feedback control loop in accordance with the motor driving mode. When the motor driving mode is switched, the correction value given by the detected current correcting circuitry is changed.

Claims

1. A motor control unit for driving a vehicle power steering motor (3) with a PWM signal and feedback-controlling motor current, comprising:

a) driving means (15) for driving said motor with a PWM signal;

b) motor driving mode switching means (14) having a plurality of motor driving modes for a driving control system of said motor and for switching said motor driving mode;

c) a feedback control loop coupled between the motor and the driving means, and including current detecting means (5) for detecting a drive current flowing through said motor, and comparing means (17) for comparing the detected motor current with a target motor current, and

d) means for preventing shocks to a steering system of the vehicle and current detection errors due to motor driving mode switching, said preventing means comprising input signal correcting means (16) coupled in said feedback control loop for correcting at least one input signal of said comparing means in accordance with said motor driving mode;

wherein the correction value given by said input signal correcting means is changed whenever said motor driving mode is switched.

2. A motor control unit for driving a vehicle power steering motor with a PWM signal and feedback-controlling motor current, comprising:

a) driving means for driving said motor with a PWM signal;

b) motor driving mode switching means (14) having a plurality of motor driving modes for a driving control system of said motor and for switching said motor driving mode;

c) a feedback control loop coupled between the motor and the driving means, and including current detecting means (5) for detecting a drive current flowing through said motor and comparing means (17) for comparing the detected motor current with a target motor current, and

d) means for preventing shocks to a steering system of the vehicle and current detection errors due to motor driving mode switching, said preventing means comprising input signal correcting means (16) coupled in said feedback control loop for correcting at least one input signal of said comparing means in accordance with the duty value of said PWM signal.

3. A motor control unit for driving a vehicle power steering motor (3) with a PWM signal and controlling the motor current by feedback, comprising:

a) driving means (15) for driving said motor with a PWM signal;

b) motor driving mode switching means (14) having a plurality of motor driving modes for a driving control system of said motor and for switching said motor driving mode;

c) a feedback control loop coupled between the motor and the driving means, and including current detecting means (5) for detecting a drive current flowing through said motor, and comparing means (17) for comparing the detected motor current with a target motor current, and

d) means for preventing shocks to a steering system of the vehicle and current detection errors due to motor driving mode switching, said preventing means comprising means for alternately switching between two driving modes for a predetermined time when said motor driving mode switching means switches the motor driving mode.

4. A motor control unit for driving a motor in a PWM mode and feedback-controlling motor current, comprising:

driving means for driving said motor in the PWM mode;

motor driving mode switching means which has a plurality of motor driving modes for the driving control system of said motor and which switches said motor driving mode; and

input signal correcting means for correcting at least one input signal of comparing means provided in a feedback control loop in accordance with said motor driving mode;

wherein the correction value given by said input signal correcting means is changed whenever said motor driving mode is switched,

and further comprising correcting value storing means (18) for storing beforehand a correction value used by said input signal correcting means;

wherein said input signal correcting means performs correction by using the correction values stored in said correction value storing means.

5. A motor control unit for driving a motor in a PWM mode and feedback-controlling motor current, comprising:

driving means for driving said motor in the PWM mode;

motor driving mode switching means which has a plurality of motor driving modes for the driving control system of said motor and which switches said motor driving mode; and

input signal correcting means for correcting at least one input signal of comparing means provided in a feedback control loop in accordance with said motor driving mode;

wherein the correction value given by said input signal correcting means is changed whenever said motor driving mode is switched, and

the corrective processing implemented by said input correcting means is repeatedly turned ON/OFF for a predetermined time when said motor driving mode is switched by said motor driving mode switching means.

6. A motor control unit for driving a motor in a PWM mode and feedback-controlling motor current, comprising:

driving means for driving said motor in the PWM mode;

motor driving mode switching means which has a plurality of motor driving modes for the driving control system of said motor and which switches said motor driving mode; and

input signal correcting means for correcting at least one input signal of comparing means provided in a feedback control loop in accordance with said motor driving mode;

wherein the correction value given by said input signal correcting means is changed whenever said motor driving mode is switched, and

the mode of said input signal correcting means is switched when the motor driving mode is switched by said motor driving mode switching means and the correction amount of said input signal correcting means is decreased as time passes.