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 Title: |
US7317293:
Displacement control system for a vehicle axle
[ Derwent Title ]
>> View Certificate of Correction for this publication
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| Country: |
US United States of America
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| Inventor: |
Takeuchi, Kesatoshi; Suwa, Japan
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| Assignee: |
Seiko Epson Corporation Japan
other patents from SEIKO EPSON CORPORATION (503380) (approx. 5,431)
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| Published / Filed: |
2008-01-08
/ 2003-10-29
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| Application Number: |
US2003000531244
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| IPC Code: |
Advanced:
B60L 15/20;
G05B 11/28;
H02P 5/00;
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| ECLA Code: |
B62K3/00D; B60L15/20; B60L15/20B; H02P5/00; L60L200/26; Y02T10/64D;
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| U.S. Class: |
318/599;
318/625;
318/608;
318/606;
318/607;
318/600;
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| Field of Search: |
318/599,625,608,606,607,621,600,254,138,439
388/811,804,911,912,812,813
363/071
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| Priority Number: |
| 2002-10-29 |
JP2002000314923 |
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| Abstract: |
Provided is a motor control circuit in which the circuit structure is not complicated, which has a favorable response to the phase difference signal, and in which the signal variation caused by heat is small. This rotation control circuit of a motor includes: a PWM control circuit of the motor; a rotational speed sensor of the motor; a reference signal generation circuit 10 ; a phase comparing circuit; and a divider for dividing the detected rotational speed signal of the motor; wherein the phase difference between the signal from the divider and the signal based on the reference signal is sought with the phase comparing unit, and this phase difference signal is supplied to the PWM control circuit.
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| Attorney, Agent or Firm: |
Harness, Dickey & Pierce, P.L.C. ;
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| Primary / Asst. Examiners: |
Masih, Karen;
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| Maintenance Status: |
CC Certificate of Correction issued
View Certificate of Correction
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| INPADOC Legal Status: |
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| Parent Case: |
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a U.S. National Stage (371) of International Application No. PCT/JP2003/013868 Oct. 29, 2003, and published in English as WO 2004/040746 A1 on May 13, 2004, which claims the benefit of Japanese Application No. 2002-314923, filed Oct. 29, 2002. The disclosures of the above applications are incorporated herein by reference.
1. Technical Field of the Invention
The present invention pertains to a PWM control circuit of a motor, and in particular to a rotation control circuit of a motor combining a PLL control circuit and a PWM control circuit. The present invention further relates to an invention employing this control circuit for controlling the drive motor for driving a driver.
2. Related Art
As this type of PWM control circuit, for example, there is a motor control circuit for an electric vehicle described in Japanese Patent Laid-Open Publication No. H5-30602.
This conventional technology has a motor circuit (CP1, TR1 to TR4) that generates a drive signal of a pulse width that changes in accordance with the acceleration voltage upon comparing the acceleration voltage and triangular wave, performs PWM control to the power transistor (TR1 to TR4) in accordance with said drive signal, and thereby energizes the motor M. Moreover, this conventional technology further comprises a current limitation circuit (Rs, CP2) for detecting the battery current supplied to the motor M and lowering the drive signal when such battery current exceeds a reference value, and a rotation number control circuit (2 to 4) for detecting the rotation number of the motor M and performing constant speed control to the motor M by changing the acceleration voltage based thereon.
Meanwhile, in order to accurately control the rotation number of the motor, a PLL circuit may be combined with this PWM control circuit. As with the control system shown in FIG. 1 enabling such a circuit, this system comprises a reference signal generation circuit 10, a circuit 12 for forming a triangular wave from this reference signal, a motor 14, a switching circuit 16 of the motor, an encoder 18 for detecting the rotation number of the motor, an N divider 20 for N dividing the detected pulse signal from the encoder, a phase comparing unit 22 for detecting the phase difference between the N divided signal and the reference pulse signal, a low pass filter 24, and a voltage comparator 25. This system forms an analog signal 26 from the low pass filter and a switch signal from the triangular wave and supplies these to the transistor gate of the switching circuit (PWM control circuit) of the motor.
In other words, the analog signal and the triangular signal are compared, and, during the period when the analog signal is higher than the triangular signal, a signal “H” is output to an amplifier 16A, and, during the period when the analog signal is lower than the triangular signal, a signal “L” is output to the amplifier 16A. Outputs from this amplifier are respectively input to the two transistor gates connected serially. Therefore, it is possible to change the duty ratio of the voltage supplied to the motor 14.
Nevertheless, with the circuit illustrated in FIG. 1, since the duty ratio control signal is obtained from an analog signal, the following problems arise in the analog circuit portion. Not only is the circuit structure complex, the response to the phase difference signal is inferior, and the signal variation caused by heat is significant.
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| Family: |
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First Claim:
Show all 7 claims |
1. A rotation control circuit of a motor, comprising: a PWM control circuit of the motor; a rotational speed sensor of the motor; a reference signal generation circuit; a phase comparing circuit; a divider for dividing the detected rotational speed signal of the motor; and rotation command means of the motor; wherein the phase difference between the signal from the divider and the signal based on the reference signal is sought with the phase comparing unit, and this phase difference signal is supplied to the PWM control circuit; and wherein the command means alters the division ratio of the divider in accordance with the contents of the rotational speed alteration request to the motor.
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| Background / Summary: |
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| Drawing Descriptions: |
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| Description: |
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| PCT Number: |
PCT/JP03/13868
WO0004/040
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| PCT Pub./Filed Dates: |
2004-05-13 / 2003-10-29
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| § 371 / 102(e) Dates: |
2005-04-14 /
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