JPH0452074B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a control device that shortens the time required to phase-synchronize a rotating body or a traveling body with a reference signal.

[Background of the invention]

In a control device for phase-synchronizing an electric motor and a similar rotating body or running body such as a tape with a reference signal, shortening the synchronization pull-in time at startup has been an important issue. Some of the known examples have drawbacks such as requiring complicated circuits or having a somewhat adverse effect on control characteristics, and therefore, improving the starting characteristics and improving the control characteristics during steady state cannot be combined.

For example, an example of a conventional phase control device is shown in FIG. In the figure, 1 is a reference signal generator, 2 is a phase comparator, 3 is a phase compensation circuit, 4 is a drive amplifier, 5 is a motor, 6 is a phase detector, and 7 is an amplifier. The phase comparator 2 detects the reference signal 8 from the reference signal generator 1 and the rotational phase of the flywheel 33 attached to the electric motor 5 with a detector 6 and amplifies it with an amplifier 7 to obtain a comparison signal 9. Compare with
A phase error signal 10 is obtained. This phase comparator 2 is
Normally, a sampling and hold type comparison circuit is used, for example, the reference signal 8 from the reference signal generator 1 is
The slope part of the trapezoidal wave signal generated based on the amplifier 7
A phase error signal 10 proportional to the phase difference between the reference signal 8 and the comparison signal 9 is obtained by sampling and holding the sipling pulse generated based on the comparison signal 9 from the reference signal 8 and the comparison signal 9 . This phase error signal 1
0 is amplified by the drive amplifier 4 via the phase compensation circuit 3 and becomes the drive signal 11 for the motor 5. FIG. 2 shows the phase error signal 10 at startup. In the figure, after the electric motor 5 starts at time a, until time b when the motor 5 settles down to a predetermined speed, the phase error signal 10
fluctuates wildly. Therefore, this phase error signal 1
The variation amount of 0 is superimposed on the drive signal 11 that should cause the electric motor 5 to reach a predetermined speed, which causes rotational fluctuations in the electric motor 5 and causes a delay in the retracting time. In addition, in the initial state until the electric motor 5 is started, no signal is detected from the detector 6, so the detection signal from the detector 6 is detected by the phase comparator 2 using a sampling and hold type circuit. The sampling pulse that should have been generated based on this was not generated, and the phase comparator 2 did not output the normal phase error signal 10, but instead outputted the phase error signal 10 with an undefined potential, which caused a delay in the pull-in time. .

[Purpose of the invention]

An object of the present invention is to provide a phase control device that eliminates the drawbacks of the prior art described above, improves startup characteristics, and shortens synchronization pull-in time at startup, with a simple configuration and without affecting control characteristics in steady state. Our goal is to provide the following.

[Summary of the invention]

In order to achieve the above object, the present invention blocks speed disturbance components or phase disturbance components that occur from startup to phase synchronization pull-in, and applies a predetermined voltage as a drive signal until a predetermined speed is reached. This allows synchronization to be carried out more quickly.

[Embodiments of the invention]

The present invention will be explained in detail below using examples.

FIG. 3 is a block diagram showing an example of the basic circuit of the present invention for improving the pull-in characteristic. In the figure, 12 is a gate signal generator, 13 is a gate circuit, and the gate circuit 13 is a transistor 14,
It consists of resistors 15 and 16 and a protection diode 17. Also shown in FIG. 4 are the gate signal 18 from the generator 12 and the gate output signal 19 from the gate circuit 13. In FIGS. 3 and 4, the transistor 14 is in the off state due to the gate signal 18 during the period up to b' when the motor 5 starts up, so that the transient phase error signal 10 as shown in FIG. Such fluctuations are not transmitted to the drive signal 11, and as a result, the electric motor 5 quickly reaches the predetermined speed, so that its rise time (a to b') is extremely quick compared to the conventional example. After time b', the transistor 14 is turned on by the gate signal 18, the gate circuit 13 becomes conductive, and its gate output signal 19 becomes equal to the phase error signal 10, so that the normal phase control loop is closed. Become.
Therefore, the time from startup to synchronization pull-in (a
~c') can be shortened by the amount of time that the rise time (a~b') is shortened.

In addition, in the present invention, the gate signal 18 is applied to the gate circuit 13 until a predetermined time b' as shown in FIG.
Therefore, the gate signal generator 12 may generate the gate signal 18 after a predetermined time b' in conjunction with a mechanical operation, or may It is also possible to use a monostable multi-function device that is triggered by a start command signal and delayed by a predetermined time b', or detects a change in the drive signal 11 of the electric motor 5 and outputs the gate signal 18 after detecting that the predetermined speed has almost been reached. It may be arranged so that it occurs.

Next, a specific embodiment of the present invention is shown in FIG.
In the figure, 13 is a first gate circuit which operates in the same way as the circuit shown in FIG. This gate circuit operates complementary to the first gate circuit 13. That is, the gate signal 18 causes the first
When the gate 13 is non-conductive, the second gate 20 is conductive, and when the first gate 13 is conductive, the second gate 20 is non-conductive. A reference voltage generator 24 generates a reference voltage 25 equal to the operating center potential at the time of synchronization pull-in of the phase control system.

The phase compensation circuit 3 generally includes resistors 30, 31 and a capacitor 32 as shown in the figure.
So-called phase lag compensation is used, but the motor 5
Since the potential charged in the capacitor 32 at the initial stage of startup is undefined, the undefined potential is added to the potential of the drive signal 11 of the motor 5 in a normal operating state, which may deteriorate the synchronization pull-in characteristic. Therefore, in this embodiment, this unnecessary component is also removed to further shorten the synchronization pull-in time.

That is, until time b' in FIG. 4 when the first gate 13 is non-conductive and the phase control loop is open, the second gate 20 is conductive and the reference voltage 25 is applied to the capacitor 32.
When the motor 5 reaches approximately a predetermined speed and the gate signal 18 generated at time b' makes the first gate 13 conductive and closes the phase control loop to a normal state. At the same time, if the second gate 20 is opened, the subsequent control operation will be quickly phase synchronized to the operation center potential stored in the capacitor 32.

Therefore, the synchronization pull-in time (b'~
Since c') can be further shortened, together with the shortening of the rise time (a to b') mentioned above, the pull-in characteristic can be significantly improved. Moreover, after the phase control loop is closed, the second gate 20
Since the capacitor 32 is completely opened, there is no external restraint on the capacitor 32, and the control operation is not affected in any way. As is clear from the above description of the operation, both the first gate circuit 13 and the second gate 20 supply the electric motor 5 with signals of undefined potential and fluctuating components, which caused a delay in the synchronization pull-in time. This has the effect of completely blocking the synchronization, and has the effect of synergistically shortening the synchronization pull-in time. That is, the first
The gate 13 completely blocks the transient fluctuation component of the phase error signal 10 output from the phase comparator 2 from being supplied to the motor 5 during the period up to synchronization pull-in. Further, at the initial stage of starting the electric motor 5, the supply of the phase error signal 10 of undefined potential outputted from the phase comparator 2 constituted by a sampling-and-hold type circuit to the electric motor 5 is completely interrupted.

Further, the second gate 20 completely blocks the supply of the electric motor 5 with a signal having an undefined potential that is charged in the capacitor 32 of the phase lag compensation circuit 3.
Furthermore, this second gate 20 has the effect of shortening the start-up time of the phase lag compensation circuit 3.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to significantly shorten the synchronization pull-in time at startup with a simple configuration and without adversely affecting the control characteristics. If applied to a playback device, the playback video time from the start of operation can be shortened and the performance of the device can be improved.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a conventional phase control device, FIG. 2 is a waveform diagram showing an example of a phase error signal, FIG. 3 is a block diagram showing an example of a basic circuit of a phase control device according to the present invention, and FIG. 5 is a waveform diagram for explaining the operation of FIG. 3, and FIG. 5 is a block diagram showing a specific embodiment of the phase control device according to the present invention. 1... Reference signal generator, 2... Phase comparator, 3
...Phase compensation circuit, 4...Drive amplifier, 5...Motor, 6...Phase detector, 7...Amplifier, 12...
...Gate signal generator, 13...Gate circuit, 20
...Gate circuit, 24...Reference voltage generator.

Claims (1)

[Claims] 1. Phase error signal with respect to reference signal 8
3 or in a control device that controls the driving means 4 and 5 of the traveling body through a phase compensation means to phase-synchronize the rotating body or the traveling body with the reference signal, when the rotating body or the traveling body reaches a predetermined speed. means 12 for detecting; phase comparison means 2 for detecting a phase difference between the rotational phase or running phase of the rotating body or running body and the reference signal; a first resistor 30 with a resistance value R ₁ ; 2nd of R ₂
a phase compensation means 3 configured as a phase delay element by connecting a resistor 31 of C and a capacitor 32 of capacitance C in cascade; Therefore, before it is detected that the rotating body or the running body has reached a predetermined speed, the supply of the phase error signal to the drive means is cut off, and when it is detected that the rotating body or the running body has reached the predetermined speed, the supply of the phase error signal to the drive means is interrupted. a first gate means 13 for supplying the phase error signal to the drive means via a phase compensation means; a reference voltage generation means 24; the first gate means supplies the phase error signal to the drive means; a second gate means 20 for applying the output voltage of the reference voltage generating means to the capacitor of the phase compensation means to supply a predetermined voltage to the driving means when the voltage is not supplied to the reference voltage generating means; phase control device. 2. The phase control device according to claim 1, wherein the second gate means includes means for charging the capacitor in advance before starting activation of the driving means. 3. The phase control according to claim 1 or 2, wherein the detection means includes means for detecting a delay of a predetermined arbitrary time from the start of activation of the drive means. Device. 4 The phase comparison means detects the rotational phase or running phase of the rotating body or the running body and generates one of the reference signal and the comparison signal by using a sampling pulse generated from the other signal. 4. The phase control device according to claim 1, further comprising means for sampling and holding the phase error signal and outputting the phase error signal.