Motor speed controller and speed control system
An electric motor speed controller includes a processor connected to the following terminals, a base voltage terminal receiving a base voltage, a first voltage terminal provided with a constant voltage, and a second voltage terminal receiving a first motor coil voltage from the processor, and a third voltage terminal receiving a second motor coil voltage from the processor. The processor provides a first control period having the second motor coil voltage be zero and a second control period having the first motor coil voltage be zero. The processor determines the motor speed by controlling a difference between a first time period in the first control period and a second time period in the second control period. The first time period corresponds to a first output voltage increase and the second time period corresponds to a second output voltage increase.
1. A speed controller for determining and controlling operation speeds of a motor, the speed controller comprising:
a processor operable to send control signals and receive feedback signals;
a base voltage terminal electrically connected to the processor and receiving a base voltage U+;
a first voltage terminal electrically connected to the processor and provided with a constant voltage;
a second voltage terminal electrically connected to the processor and receiving a first motor coil voltage U 2 determined by the processor; and
a third voltage terminal electrically connected to the processor and receiving a second motor coil U 3 voltage determined by the processor;
wherein the processor provides a first control period T 1 having the second motor coil voltage of the third voltage terminal be zero and a second control period having the first motor coil voltage U 2 of the second voltage terminal be zero, and wherein the processor determines a rotation speed of the motor by controlling a value difference between a first time period t 1 in the first control period T 1 and a second time period t 3 in the second control period, the first time period t 1 corresponding to a first increase in an output voltage U 0 and the second time period t 3 corresponding to a second increase in the output voltage U 0 ,
wherein the output voltage U o , the base voltage U + constant voltage U 1 , the first motor coil voltage U 2 , and the second motor coil voltage U 3 satisfy the following relationship:
U
O
=
U
+
+
U
+
C
F
∫
(
1
R
1
+
1
R
2
+
1
R
3
)
dt
-
1
C
F
∫
(
U
1
R
1
+
U
2
R
2
+
U
3
R
3
)
dt
wherein C F is a value of a capacitor in an amplifier integrator circuit and R 1 , R 2 , and R 3 are values of respective resistors between the first voltage terminal, the second voltage terminal and the third voltage terminal and the amplifier integrator circuit.
2. The speed controller of claim 1 , wherein the processor receives a feedback signal produced from the output voltage U 0 .
3. The speed controller of claim 1 , wherein a value RS of armature and brush resistance of the motor and a value R Sense of a resistor sensor measuring motor coil current of the motor satisfy the following relationship:
R
s
=
R
2
R
Sense
R
3
4. The speed controller of claim 3 , wherein a first time difference between the first control period T 1 and the first time period t 1 is the same as a second time difference between the second control period T 2 and the second time period t 3 , the first time difference denoted to and the second time difference denoted t 2 .
5. The speed controller of claim 4 , wherein the rotation speed n of the motor is proportional to a constant value difference between t 3 and t 1 .
6. The speed controller of claim 5 , wherein the rotation speed n and the constant value difference between t 3 and t 1 satisfy the following relationship:
n
=
R
2
t
0
K
E
[
U
+
(
1
R
1
+
1
R
2
+
1
R
3
)
-
U
1
R
1
]
(
t
1
-
t
3
)
wherein K E is a constant of back electromotive force of the motor.
7. The speed controller of claim 6 , wherein the base voltage U + is set at zero, the constant voltage U 1 is set at 5 V, the first motor coil voltage U 2 is greater than zero, and the second motor coil voltage U 3 is set at zero during the first time difference t 0 .
8. The speed controller of claim 6 , wherein the base voltage U + is set at 0.5 V, the constant voltage U 1 is set at 5 V, the first motor coil voltage U 2 is set at zero, and the second motor coil voltage U 3 is set at zero during the first time period t 1 .
9. The speed controller of claim 8 , wherein the processor sends a command voltage of 5 V to an input terminal IN 1 of the speed controller during the first time period t 1 .
10. The speed controller of claim 6 , wherein the base voltage U + is set at zero, the constant voltage U 1 is set at 5 V, the first motor coil voltage U 2 is set at zero, and the second motor coil voltage U 3 is greater than zero during the second time difference t 2 .
11. The speed controller of claim 6 , wherein the base voltage U + is set at 0.5 V, the constant voltage U 1 is set at 5 V, the first motor coil voltage U 2 is set at zero, and the second motor coil voltage U 3 is set at zero during the second time period t 3 .
12. The speed controller of claim 11 , wherein the processor sends a command voltage of 5 V to an input terminal IN 1 of the speed controller during the second time period t 3 .
13. The speed controller of claim 1 , wherein the motor is a brushed direct current motor and the processor provides a pulse width modulation signal to drive the motor.
14. An actuator control system for use with a motor operable to move an actuator, the actuator control system comprising:
a speed controller configured to determine and control a speed of the motor, wherein the speed controller comprises:
a processor configured to send control signals and receive feedback signals; and
an interface configured to receive a base voltage U+,
provide a constant voltage,
receive a first motor coil voltage U 2 , and
receive a second motor coil voltage U 3 ;
wherein the processor is configured to provide a first control period T 1 having the second motor coil voltage U 3 be zero and a second control period having the first motor coil voltage be zero, and wherein the processor in configured to determine the speed of the motor by maintaining a constant value difference between a first time period t 1 in the first control period T 1 and a second time period t3 in the second control period, the first time period t 1 corresponding to a first increase in an output voltage U 0 and the second time period t 3 corresponding to a second increase in the output voltage U 0 ,
wherein the output voltage U o , the base voltage U + constant voltage U 1 , the first motor coil voltage U 2 , and the second motor coil voltage U 3 satisfy the following relationship:
U
O
=
U
+
+
U
+
C
F
∫
(
1
R
1
+
1
R
2
+
1
R
3
)
dt
-
1
C
F
∫
(
U
1
R
1
+
U
2
R
2
+
U
3
R
3
)
dt
wherein C F is a value of a capacitor in an amplifier integrator circuit and R 1 , R 2 , and R 3 are values of respective resistors between first voltage terminal, second voltage terminal and third voltage terminal and the amplifier integrator circuit, and wherein the motor is a direct current brush motor and the processor is configured to provide a pulse width modulation signal to drive the motor.
15. The actuator control system of claim 14 , wherein the processor comprises an integrator circuit and a comparator circuit, and the processor is configured to receive a feedback signal produced from the output voltage U 0 .
16. The actuator control system of claim 14 , wherein a value RS of armature and brush resistance of the motor and a value R Sense of a resistor sensor measuring motor coil current of the motor satisfy the following relationship:
R
s
=
R
2
R
Sense
R
3
17. The actuator control system of claim 16 , wherein a first time difference between the first control period T 1 and the first time period t 1 is the same as a second time difference between the second control period T 2 and the second time period t 3 , the first time difference denoted t 0 and the second time difference denoted t 2 ; and wherein rotation speed n of the motor is proportional to the constant value difference between t 3 and t 1 .