Current control type circuit for brushless motor

• US 4,631,458 A
• Filed: 10/25/1985
• Issued: 12/23/1986
• Est. Priority Date: 10/26/1984
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Furuichi, Tokinori
• Primary Examiner(s): Shoop, Jr., William M.
• Assistant Examiner(s): Ro, Bentsu
• Application Number:
  US06/791,344
• Time in Patent Office: 424 Days
• Field of Search: 318/138, 318/254 A, 318/254, 318/439, 318/307, 318/309, 318/330, 318/346, 318/599, 318/811
• US Class Current: 318/400.04
• CPC Class Codes: H02P 6/06 Arrangements for speed regulation of a single motor wherein the motor speed is measured and compared with a given physical value so as to adjust the motor speed

Abstract

There is provided a chopping, current-control type driver circuit for brushless motor including a circuit for effecting chopping on the basis of a speed/phase error signal, a changeover circuit for changing over the current direction of Hall devices depending upon whether said error signal is positive or negative, switch circuit for supplying power to stator coils on the basis of the Hall device output, a current detection device, and an amplifier serving as an inverting amplifier or a noninverting amplifier depending upon whether the error signal is positive or negative, wherein a negative feedback signal is applied to the error signal in the form of the current value detected by the current detection device in order to control the current flowing through the motor stator.

Claims

1. A driver circuit for a motor having stator coils comprising:

error detector means for detecting the rotation phase of the motor and generating an error signal;

amplifier means for amplifying said error signal;

control signal generator means for generating an interrupted control signal on the basis of the amplified error signal of said amplifier means;

switch means for supplying an interrupted current to said stator coils in response to the control signal and having a polarity corresponding to the polarity of said error signal;

current detector means for generating a detected voltage dependent upon the magnitude of the interrupted current supplied to said stator coils, said current detector means being placed in the path of the interrupted current supplied said stator coils; and

negative feedback means for negatively feeding back the detected voltage with a polarity dependent upon the polarity of said error signal to said amplifier means.

2. A driver circuit according to claim 1, wherein said switch means includes polarity determining means connected to the output of said amplifier means, said polarity determining means generating a determination signal when said error signal has a polarity indicating a phase delay, and wherein said negative feedback means includes inverting means for inverting the polarity of the detected voltage when said determination signal is supplied thereto.

3. A motor driver circuit comprising:

a speed error detector for detecting the speed error of a motor;

a speed error signal amplifier for amplifying the output signal of said speed error detector;

a comparator for determining the polarity of the speed error signal;

an inverting/noninverting amplifier for amplifying the output signal of said speed error signal amplifier, said inverting/noninverting amplifier being switched into the inverting mode or noninverting mode on the basis of the signal supplied from said comparator;

signal generating means for generating a chopping signal on the basis of the output signal of said inverting/noninverting amplifier;

a switching element for controlling the current flowing from the power supply to a motor stator on the basis of the output signal of said signal generating means;

a current changeover circuit for changing over the current flowing into the motor stator on the basis of the output signal of said comparator;

means for supplying power to the stator on the basis of the output of said current changeover circuit;

means for detecting the value of a current flowing through the motor stator; and

an inverting/noninverting amplifier for amplifying said current value in the inverting mode or noninverting mode depending upon the polarity of said speed error signal, a negative feedback signal being applied to said speed error signal amplifier in the form of said current value to control the current flowing through stator coils in response to said speed error signal.