JPS6367440B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a synchronous circuit for rotating a motor in synchronization with a reference frequency.

[Conventional technology]

An example of a conventional circuit of this kind is shown and explained in FIG. 1. FIG. 1 is an explanatory diagram of a conventional method (PLL) used to synchronize the frequency of an oscillator or the rotational speed of a motor with a reference frequency. In the figure,
1 is a motor, 2 is an input terminal to which a motor drive signal is applied, 3 is a rotation detection winding that detects the rotation of the motor 1, 4 is a phase detector, and 5 is a phase whose input is the output of the phase detector 4. A wave generator for correction, 6 a motor drive amplifier composed of transistors, and 7 an input terminal to which a reference frequency signal is applied. Here, the phase detector 4 constitutes a phase lock loop (PLL).

Since the operation of a circuit having such a configuration is generally well known, a detailed explanation thereof will be omitted. The phase of the frequency is compared with the input signal, an output with a pulse width corresponding to the phase difference is extracted, and the output is made into a DC value with the AC component removed by the wave generator 5, and is passed through the motor drive amplifier 6 to the motor drive input terminal 2. By feeding back to the rotation speed, synchronous rotation is performed. In this case, the internal constants of the wave device 5 for phase correction must be selected so that the control system does not enter a vibration state.

[Problem to be solved by the invention] However, in such a synchronous circuit, not only is it complicated to determine the constants of the wave generator, but also the time constant is generally large, so the response to disturbances is slow. Ta.

In view of the above points, the present invention has been made to solve such problems.

[Means to solve the problem]

A rotation detection winding that detects the rotation of the motor, a detection output of the rotation detection winding, and a reference frequency signal are input, and a phase difference between the detection output of the rotation detection winding and the reference frequency signal is determined. a phase detector that outputs a signal with a pulse width proportional to the phase difference; a rotation speed detection circuit that receives the detection output of the rotation detection winding as an input and includes a peak value detector of the detection output of the rotation detection winding; The output voltage of the rotation speed detection circuit and a reference voltage indicating a reference value of the motor rotation speed at the reference frequency are input, and if the output voltage of the rotation speed detection circuit is smaller than the reference voltage, a voltage higher than the reference voltage is input. an amplitude control circuit which generates a low voltage in the case of high voltage and vice versa; the emitter of the transistor is grounded, the output of the phase detector is connected to the base of the transistor, and the output of the amplitude control circuit is connected to the The multiplication circuit is connected to a collector of a transistor and outputs a multiplication value from the collector of the transistor, and a motor driving amplifier that drives the motor using the multiplication output of the multiplication circuit.

[Effect]

With this configuration, the amplitude changes in response to the motor rotation speed, when the rotation speed is lower than the reference rotation speed, the amplitude is high, and when the rotation speed is high, the amplitude changes to low. A pulse signal whose pulse width changes in proportion to the phase difference between the two is obtained. Therefore, by driving the motor using this pulse signal, the motor can be caused to perform synchronous rotation.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

FIG. 2 is a block diagram showing an embodiment of a synchronous circuit according to the present invention. In FIG. 2, the same reference numerals as in FIG. 1 indicate corresponding parts. 8 is the first operational amplifier, 9 is a diode (rectifier) that rectifies the output of the first operational amplifier 8, and 10 is a capacitor (capacitance) connected to the output side of the rectifier 9, which detects the peak value. A rotation detection circuit is constituted, and this rotation detection circuit constitutes means for detecting a signal having an amplitude corresponding to the number of rotations of the motor 1. 11 is a second operational amplifier; 12 is an input terminal to which a reference voltage indicating a reference value of the motor rotation speed at the synchronous pull-in reference frequency is applied; these compare the detection voltage of the rotation detection circuit with the reference voltage; An amplitude control circuit is configured to change the output according to the magnitude relationship between the two. Reference numeral 13 denotes a transistor constituting a multiplication circuit for obtaining the product of pulse width and amplitude.

The phase detector 4 constitutes a signal extraction means for extracting a signal in which the polarity of the pulse width, which is proportional to the phase difference between the reference frequency signal from the reference frequency input terminal 7 and the rotation of the motor 1, is inverted.

Next, the operation of the embodiment shown in FIG. 2 will be explained. First, since the output amplitude from the rotation detection winding 3 is proportional to the rotation speed of the motor 1, the peak value detector is composed of a first operational amplifier 8, a diode 9, and a capacitor 10, which uses it as an input. The output of the rotation speed detection circuit also has a value proportional to the rotation speed of the motor 1. Further, in the amplitude control circuit, the output of the rotation speed detection circuit and the reference voltage from the input terminal 12 are compared, and the output of the second operational amplifier 11 is changed depending on the magnitude relationship between the two. That is, when the rotation speed of the motor 1 is smaller than the reference value, the output of the second operational amplifier 11 is input to the input terminal 1.
Control is performed so that the voltage is higher than the reference voltage from 2, and in the opposite case, the voltage is lower. Here, the phase detector 4 is connected to the transistor constituting the multiplier circuit 13.
If a pulse input is given from , a pulse signal whose amplitude is the same as the output voltage of the second operational amplifier 11 of the amplitude control circuit and whose pulse width is equal to the input pulse width is obtained, and this pulse signal is sent to the motor drive amplifier. The signal is supplied to the motor drive input terminal 2 through the transistor 6.

Note that the operation of the phase detector 4 is the same as in the case of FIG. 1, but in the embodiment shown in FIG. Use.

In this way, the rotation of the motor 1 is controlled by a signal whose amplitude changes according to the rotation speed of the motor 1 and whose pulse width changes according to the phase difference between the rotation of the motor 1 and the reference frequency signal, Since the response of pulse value detection is faster than the time constant of the motor 1, a synchronous circuit can be realized with a simple circuit configuration without using complicated means such as a phase correction circuit as in the past. I can do it.

〔effect〕

As explained above, according to the present invention, a motor can be directly driven with a pulse signal whose pulse width and amplitude are simultaneously controlled, without using complicated means such as correcting the phase using a wave generator as in the past. Since synchronous rotation can be performed using a simple circuit configuration, there is an advantage that stable synchronous operation with quick response to disturbances can be obtained.

As described above, the present invention has great effects compared to conventional circuits of this type, and is unique as a synchronous circuit that rotates a motor in synchronization with a reference frequency.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an example of a conventional synchronous circuit, and FIG. 2 is a block diagram showing an embodiment of the synchronous circuit according to the present invention. DESCRIPTION OF SYMBOLS 1... Motor, 3... Rotation detection winding, 4... Phase detector, 7... Reference frequency input terminal, 8... First operational amplifier, 9... Diode, 10... Capacitor, 11... Second operational amplifier, 12...
Input terminal, 13...multiplication circuit.

Claims (1)

[Claims] 1. A rotation detection winding that detects the rotation of a motor, a detection output of the rotation detection winding and a reference frequency signal, and a detection output of the rotation detection winding and a reference frequency signal. a phase detector that calculates a phase difference and outputs a signal with a pulse width proportional to the phase difference; and a peak value detector that receives the detection output of the rotation detection winding as an input and outputs a peak value detector of the detection output of the rotation detection winding. a rotation speed detection circuit, and an output voltage of the rotation speed detection circuit and a reference voltage indicating a reference value of the motor rotation speed at a reference frequency as input, and when the output voltage of the rotation speed detection circuit is smaller than the reference voltage, an amplitude control circuit that generates a voltage higher than the reference voltage and generates a lower voltage in the opposite case; A multiplication circuit that connects the output of the circuit to the collector of the transistor through a resistor and outputs a multiplication output from the collector of the transistor, and a motor drive amplifier that drives the motor using the multiplication output of the multiplication circuit. Characteristic synchronous circuit.