DC motor rotation detecting apparatus and DC motor rotation control apparatus

• US 6,617,816 B2
• Filed: 12/27/2000
• Issued: 09/09/2003
• Est. Priority Date: 12/27/1999
• Status: Expired due to Fees

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited
• Inventors: Koyama, Kenji, Tsurukawa, Ikuya, Ohno, Yoshimi
• Primary Examiner(s): Nappi, Robert E.
• Assistant Examiner(s): SMITH, TYRONE W
• Application Number:
  US09/747,952
• Publication Number:
  US 20010022505A1
• Time in Patent Office: 986 Days
• Field of Search: 318/138, 318/139, 318/245, 318/254, 318/439, 318/808, 318/812, 318/560, 318/685
• US Class Current: 318/560
• CPC Class Codes: H02K 23/66 Structural association with auxiliary electric devices influencing the characteristic of, or controlling, the machine, e.g. with impedances or switches
• CPC Class Codes: H02P 7/0094 wherein the position is detected using the ripple of the current caused by the commutator
• CPC Class Codes: H02P 7/28 using semiconductor devices

Abstract

A rotation detector apparatus and a rotation control apparatus for the DC motor is disclosed wherein rotational operations of a rotor of the DC motor are controlled by detecting at least one of the rotational direction, the rotational speed, the cumulative rotation number, and the rotational position of the rotor. The pulsed output signal from at least one motor rotor rotation detector brush is processed by signal processing circuitry to regulate the at least one of the rotational direction, the rotational speed, the cumulative rotation number, and the rotational position of the rotor.

Claims

1. A DC motor rotation detector apparatus configured to detect at least one of a rotational direction, a rotational speed, a rotational position, and a cumulative rotation number of a rotor of a DC motor, comprising:

at least one rotation detector brush configured to detect a rotation of the rotor;

a reference voltage device configured to generate a reference voltage; and

a comparator configured to compare a voltage detected by the rotation detector brush with the reference voltage generated by the reference voltage device to generate a pulse train of pulse period corresponding to the rotation speed of the rotor.

2. The DC motor rotation detector apparatus according to claim 1, wherein the reference voltage device further comprises:

a device that divides a DC drive voltage and obtains the reference voltage.

3. A DC motor rotation control apparatus configured to control at least one of a rotational direction, a rotational speed, a rotational position, and a cumulative rotation number of a rotor of a DC motor, comprising:

at least one rotation detector brush configured to detect a rotation of the rotor;

a motor driver circuit configured to apply a DC drive voltage to a pair of electrode brushes and to drive the DC motor;

a reference voltage device configured to generate plural reference voltages which correspond respectively to at least one of different rotational directions of the rotor and voltages applied to the DC motor;

a comparator configured to compare the voltage detected by the rotation detector brush with one of the plural reference voltages generated by the reference voltage device to generate a pulse train of pulse period corresponding to the rotational speed of the rotor; and

a motor control circuit configured to apply the reference voltage to the comparator and to control the motor driving circuit by reacting to an output signal of the comparator.

4. The DC motor rotation control apparatus according to claim 3, wherein the motor control circuit further comprises:

a pulse interval measurement device configured to measure a pulse interval of output pulses of the comparator;

a rotational speed calculator device configured to calculate rotational speed of the rotor based on the pulse interval measured by the pulse interval measurement device;

a rotational speed comparator device configured to compare the rotational speed of the rotor calculated by the rotational speed calculator device with a target rotational speed of the rotor; and

a chopping control device configured to control a drive output signal of the motor driver circuit by performing chopping control based on a comparison result obtained by the rotational speed comparator device such that the rotational speed of the rotor reaches the target rotational speed.

5. The DC motor rotation control apparatus according to claim 4, wherein the motor control circuit further comprises:

a rotational speed detection suppressor device configured to invalidate a rotational speed detection result measured by the pulse interval measurement device when a chopping operation is performed by the chopping control device.

6. A DC motor rotation detection method for detecting at least one of a rotational direction, a rotational speed, a rotational position, and a cumulative rotation number of a rotor of a DC motor, comprising:

detecting a rotation of the rotor using least one rotation detector brush;

generating a detection voltage;

generating a reference voltage; and

comparing the detection voltage with the reference voltage to generate a pulse train of pulse period corresponding to the rotational speed of the rotor.

7. The DC motor rotation detection method according to claim 6, wherein the step of generating the reference voltage further comprises:

dividing a DC drive voltage and obtaining the reference voltage.

8. A DC motor rotation control method for controlling at least one of a rotational direction, a rotational speed, a rotational position, and a cumulative rotation number of a rotor of a DC motor, comprising:

detecting a rotation of the rotor using at least one rotation detector brush;

generating a detection voltage;

driving the DC motor with a motor driving circuit by applying a DC drive voltage to a pair of electrode brushes;

generating plural reference voltages which correspond respectively to at least one of different rotational directions of the rotor and voltages applied to the DC motor;

comparing the voltage detected by the rotation detector brush with one of the plural reference voltages using a comparator to generate a pulse train of pulse period corresponding to the rotational speed of the rotor;

applying the reference voltage to the comparator using a motor control circuit; and

controlling the motor driving circuit by reacting to an output signal of the comparator.

9. The DC motor rotation control method according to claim 8, wherein the step of controlling the motor driving circuit further comprises:

measuring a pulse interval of output pulses of the comparator;

calculating a rotational speed of the rotor based on the pulse interval;

comparing the rotational speed of the rotor with a target rotational speed of the rotor; and

controlling a device output signal of the motor driver circuit by performing chopping control such that the rotational speed of the rotor reaches the target rotational speed.

10. The DC motor rotation control method according to claim 9, wherein the step of controlling the motor driving circuit further comprises:

suppressing an invalid rotational speed detection result when a chopping operation is performed.

11. A DC motor rotation detector configured to detect at least one of a rotational direction, a rotational speed, a rotational position, and a cumulative rotation number of a rotor of a DC motor, comprising:

at least one rotation detection means for detecting a rotation of the rotor;

a reference voltage generating means for generating a reference voltage; and

a comparing means for comparing a voltage detected by the rotation detection means with the reference voltage generated by the reference voltage generating means to generate a pulse train of pulse period corresponding to the rotational speed of the rotor.

12. The DC motor rotation detector according to claim 11, wherein the reference voltage generating means further comprises:

a voltage dividing means for dividing a DC drive voltage and obtaining the reference voltage.

13. A DC motor rotation control apparatus configured to control at least one of a rotational direction, a rotational speed, a rotational position, and a cumulative rotation number of a rotor of a DC motor, comprising:

at least one rotation detection means for detecting a rotation of the rotor;

a motor driving means for applying a DC drive voltage to a pair of electrode brushes and for driving the DC motor;

a reference voltage generating means for generating plural reference voltages which correspond respectively to at least one of different rotational directions of the rotor and voltages applied to the DC motor;

a comparator means for comparing the voltage detected by the rotation detection means with one of the plural reference voltages generated by the reference voltage generating means to generate a pulse train of pulse period corresponding to the rotational speed of the rotor; and

a motor control means for applying the reference voltage to the comparator means and for controlling the motor driving means by reacting to an output signal of the comparator means.

14. The DC motor rotation control apparatus according to claim 13, wherein the motor control means further comprises:

a pulse interval measurement means for measuring a pulse interval of output pulses of the comparator means;

a rotational speed calculator means for calculating rotational speed of the rotor based on the pulse interval measured by the pulse interval measurement means;

a rotational speed comparator means for comparing the rotational speed of the rotor calculated by the rotational speed calculator means with a target rotational speed of the rotor; and

a chopping control means for controlling a drive output signal of the motor driving means by performing chopping control based on a comparison result obtained by the rotational speed comparator means such that the rotational speed of the rotor reaches the target rotational speed.

15. The DC motor rotation control apparatus according to claim 14, wherein the motor control means further comprises:

a rotational speed detection suppressor means for invalidating a rotational speed detection result measured by the pulse interval measurement means when a chopping operation is performed by the chopping control means.

21. The DC motor rotation control apparatus according to claim 13, wherein the motor control means further comprises at least one of:

a reference voltage selecting signal generating means for generating a reference voltage selecting signal,

a motor control signal generating means for generating a motor control signal,

a pulse number counting means for a counting a pulse number,

a cumulative rotational number calculating means for calculating a cumulative rotational number, and

a remaining rotational number calculating means for calculating a remaining rotational number.

16. An apparatus using a DC motor rotation detector device configured to detect at least one of a rotational direction, a rotational speed, a rotational position, and a cumulative rotation number of a rotor of a DC motor, said DC motor rotation detector device comprising:

at least one rotation detector brush configured to detect a rotation of the rotor;

a reference voltage device configured to generate a reference voltage; and

a comparator configured to compare a voltage detected by the rotation detector brush with the reference voltage generated by the reference voltage device to generate a pulse train of pulse period corresponding to the rotational speed of the rotor.

17. The apparatus according to claim 16, wherein the reference voltage device further comprises:

a device that divides a DC drive voltage and obtains the reference voltage.

18. An apparatus using a DC motor rotation control device configured to control at least one of a rotational direction, a rotational speed, a rotational position, and a cumulative rotation number of a rotor of a DC motor, said DC motor rotation control device comprising:

at least one rotation detector brush configured to detect a rotation of the rotor;

a motor driver circuit configured to apply a DC drive voltage to a pair of electrode brushes and to drive the DC motor;

a reference voltage device configured to generate plural reference voltages which correspond respectively to at least one of different rotational directions of the rotor and voltages applied to the DC motor;

a comparator configured to compare the voltage detected by the rotation detector brush with one of the plural reference voltages generated by the reference voltage device to generate a pulse train of pulse period corresponding to the rotational speed of the rotor; and

a motor control circuit configured to apply the reference voltage to the comparator and to control the motor driving circuit by reacting to an output signal of the comparator.

19. The apparatus according to claim 18, wherein the motor control circuit further comprises:

a pulse interval measurement device configured to measure a pulse interval of output pulses of the comparator;

a rotational speed calculator device configured to calculate rotational speed of the rotor based on the pulse interval measured by the pulse interval measurement device;

a rotational speed comparator device configured to compare the rotational speed of the rotor calculated by the rotational speed calculator device with a target rotational speed of the rotor; and

a chopping control device configured to control a drive output signal of the motor driver circuit by performing chopping control based on a comparison result obtained by the rotational speed comparator device such that the rotational speed of the rotor reaches the target rotational speed.

20. The apparatus according to claim 19, wherein the motor control circuit farther comprises:

a rotational speed detection suppressor device configured to invalidate a rotational speed detection result measured by the pulse interval measurement device when a chopping operation is performed by the chopping control device.

22. The apparatus according to claim 18, wherein the motor control circuit further comprises at least one of:

a reference voltage selecting signal generating device,

a motor control signal generating device,

a pulse number counting device,

a cumulative rotational number calculating device, and

a remaining rotational number calculating device.

23. The apparatus according to claim 18, wherein the motor control circuit further comprises at least one of:

a reference voltage selecting signal generating device,

a motor control signal generating device,

a pulse number counting device,

a cumulative rotation number calculating device,

a remaining rotation number calculating device,

a pulse interval measuring device,

a rotational speed calculating device, and

a rotational speed comparing device.

24. The apparatus according to claim 18, wherein the motor control circuit further comprises at least one of:

means for generating a reference voltage selecting signal,

means for generating a motor control signal,

means for counting a pulse number,

means for calculating a cumulative rotation,

means for calculating a remaining rotation number,

means for measuring a pulse interval,

means for calculating a rotational speed, and

means for comparing a rotational speed.