JPS6123741B2 - - Google Patents

Description

[Detailed description of the invention] [Technical field to which the invention pertains] The present invention relates to a synchronous operation control circuit that connects a plurality of devices each having a voltage-controlled oscillator, such as an inverter, to an oscillation bus so that they can operate accurately in synchronization. Regarding.

[Prior art and its problems]

Conventional methods for synchronous operation of multiple devices having voltage controlled oscillators include a method of synchronizing the outputs of the voltage controlled oscillators with each other in order to synchronize the frequency and phase of the devices, and a method of synchronizing the outputs of the voltage controlled oscillators. A method has been used in which an oscillator is provided and each voltage controlled oscillator is synchronized with the oscillator. However, the former has disadvantages in that the circuit becomes extremely complex when the number of synchronized units increases, and the latter suffers from loss of synchronization between the oscillators if a failure occurs in the common main oscillator. Yet another method is to provide a synchronous bus and connect each oscillator to this via an inverting amplifier with a buffer function and a resistor, and calculate the phase by regarding the voltage generated across the resistor as the phase difference between the oscillators. There is a method of performing comparative detection and synchronization using a comparator, but this method has drawbacks such as it is extremely difficult to determine the phase difference and synchronization control becomes impossible when the number of oscillators increases.

[Purpose of the invention]

Therefore, an object of the present invention is to connect the control terminals of a plurality of voltage-controlled oscillators to one signal line, that is, an oscillation bus, so that these oscillators can automatically and easily oscillate at the same frequency and the same phase. Another object of the present invention is to provide a synchronous operation control circuit that can perform highly reliable synchronous control.

[Key points of the invention]

In order to achieve such an objective, the present invention
In a plurality of devices each having a voltage controlled oscillator, a setting input is given to the voltage controlled oscillator of each device so that the output frequency of each device is equal to each other, and the output phase of each device is made to match each other. A phase comparator is provided for comparing the output phase of each device with a reference phase common to all to form a complementary setting input for the corresponding voltage-controlled oscillator. , the common reference phase is provided by forming an AND signal of the outputs of each device.

According to an embodiment of the invention, the AND signal at the output of each device is formed using a wired-or AND function.

〔Example〕

The invention will be explained in more detail below with reference to illustrated embodiments.

FIG. 1 is a diagram showing an embodiment of the present invention. A,
B is a device part constituting a part of a device, such as an inverter device, each equipped with a voltage controlled oscillator, and O is an oscillation bus that interconnects them. Although there are two devices illustrated in FIG. 1, more than two devices can be connected to the oscillation bus O. Each device A, B... is a voltage controlled oscillator 1,
It is composed of a wave generator 2, a frequency setter 3, a phase comparator circuit 4, inverting amplifiers 5 and 6, a resistor 7, and the like. The wave generator 2 is a low-pass filter, and the phase comparator circuit 4 generates an output signal having a polarity corresponding to the phase lead/lag of the output of the oscillator 1 with respect to the reference voltage signal on the oscillation bus O. Inverting amplifiers 5 and 6
connects the output of the oscillator 1 to the oscillation bus O and simultaneously supplies this output to the phase comparator 4. The resistor 7 is necessary when the inverting amplifier 6 is an open collector, and is used to raise the inverting amplifier output to the level of the reference voltage signal. The frequencies of each device A, B, . . . can be set individually, and these frequencies are set to be almost the same. However, since errors in the frequency system are usually integrated, no matter how accurate this frequency setting is, it is not practical for synchronous operation. Therefore, it is practical to provide an oscillation bus O and synchronize each voltage-controlled oscillator with this bus. In this embodiment, the output of the voltage controlled oscillator 1 is connected to the oscillation bus O via inverting amplifiers 5 and 6, and the output of the voltage controlled oscillator 1 is connected to the oscillation bus O via a wired OR.
is formed. In this case, the inverting amplifiers 5 and 6 act as buffer amplifiers that make the coupling between the output buses of the respective oscillation units A, B, . . . coarse.

FIG. 2 is a diagram showing pulse waveforms representing the synchronization relationship of a device having three voltage-controlled oscillators operating in synchronization with each other. Figure 2 a, b, and c show the pulse waveforms of the first, second, and third oscillators, respectively, and Figure 2 d shows the wired-OR waveform of these pulse waveforms. This signal waveform becomes the reference voltage signal of the oscillation bus O.
With respect to the wired-OR waveform in FIG. 2d, the pulse waveform in FIG. _2a is almost in phase, the pulse waveform in FIG. The waveform is delayed by a phase angle _φ2 . The phase comparator circuit 4 detects and calculates these phase leads and lags to correct the oscillation frequency of each voltage-controlled oscillator 1. Can be synchronized.

If an abnormality occurs in this oscillation bus O, there is a possibility that the voltage controlled oscillators A, B, . As a countermeasure for such a case, it is effective to duplicate the circuits after the inverting amplifier.

By the way, the phase comparator circuit 4 of each device A, B, C
compares the phase of the pulse waveform (reference phase) in FIG. 2d and the output pulse waveform of each device. Many methods of comparing the phases of such two pulse waveforms are known in the art, and can be designed as appropriate as required. However, in order to further deepen the understanding of the present invention, an example of such a phase comparator circuit 4 is shown in FIG. In this FIG. 3, 11 is an exclusive OR circuit, which combines the pulse waveform of FIG. 2 d, the pulse waveform of FIG. 2 a for device A, and the pulse waveform of FIG. A logical OR signal T is formed with the pulse waveform shown in FIG. 2b and, in the case of device C, the pulse waveform shown in FIG. 2c. Therefore, in FIG. 3, a, b, c, and d are the same as a, b, and d in FIG.
Corresponding to c and d, a, b, c are written in one input of the exclusive OR circuit 11 as d and a in device A, d and b in device B,
In device C, d and c are listed together for comparison. 12 is a triangular wave generator consisting of two integrators, 13 is a zero cross comparator that detects the passing of the zero point of the output signal U of the triangular wave generator 12, and 14, 15, 16, and 17 are AND circuits, respectively. 18 and 19 are switches for forming analog signals, which are operated by the outputs of AND circuits 16 and 17. moreover,
T...Z and E are output signals of each part, and V _p is a voltage source.

Therefore, when the phase comparator circuit shown in FIG. 3 is used as the phase comparator circuit of device A, the output waveforms of each part become as shown in FIG. 4A. 4th A
In the figure, the subscript A is added to the output T...Z etc. of each part in Figure 3.
It is attached and corresponded to. In this case, since waveform d and waveform a are in phase, the output signal E _A appears with the same value on + and -, and therefore disappears when smoothed by waveform generator 2 (FIG. 1).

Next, when the phase comparison circuit shown in FIG. 3 is used as the phase comparison circuit of device B, the output waveforms of each part become as shown in FIG. 4B. Similarly, in FIG. 4B, the subscript B is attached to the outputs T, . . . , Z, etc. of each part in FIG. 3 to make them correspond. In this case,
Since waveform b leads waveform d by a phase angle φ ₁ , +V _p appears in the output signal E _B , and therefore the voltage controlled oscillator is activated by the positive voltage smoothed by waveform generator 2 (Figure 1). is controlled. This smoothed positive voltage component corresponds to an advanced phase angle φ ₁ .

Furthermore, the phase comparison circuit shown in FIG.
When used as a phase comparator circuit, the output waveforms of each section are as shown in FIG. 4C. Similarly,
In FIG. 4C, a subscript C is attached to the outputs T...Z, etc. of each part in FIG. 3 to make them correspond. In this case, since waveform c lags waveform d by a phase angle φ ₂ , -V _p appears in the output signal E _c , and is therefore a negative voltage smoothed by waveform generator 2 (Figure 1). The voltage controlled oscillator is similarly controlled. This smoothed negative voltage component corresponds to the delayed phase angle _φ2 .

Note that the operations in which FIG. 3 corresponds to those in FIGS. 4A to 4C are easily understood and will therefore be omitted.

The field of application of the present invention includes oscillators for synchronous operation of AC power supplies.

〔Effect of the invention〕

As an effect of the present invention, it is possible to obtain a voltage controlled oscillator in which a plurality of devices each having a voltage controlled oscillator can be easily synchronized using one oscillation bus.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of the voltage controlled oscillator of the present invention. FIG. 2 is a diagram showing pulse waveforms representing the synchronization relationship between voltage controlled oscillators. FIG. 3 is a circuit diagram showing an example of the phase comparator circuit in FIG. 1. 4A, 4B, and 4C are waveform diagrams showing output waveforms of each section in FIG. 3, respectively. [Description of symbols] 1: Voltage controlled oscillator, 2:
Wave device, 3: Frequency setting device, 4: Phase comparator circuit,
5, 6: inverting amplifier, 7: resistor, A, B...: device having a voltage controlled oscillator, O: oscillation bus.

Claims (1)

[Claims] 1 In a plurality of devices each equipped with a voltage controlled oscillator, a setting input is given to the voltage controlled oscillator of each device so that the output frequency of each device is equal to each other, and the output phase of each device is made to match each other. a phase comparator that compares the output phase of each device with a reference phase common to all to form a complementary setting input for the corresponding voltage-controlled oscillator; A synchronous operation control circuit, characterized in that the common reference phase is provided by forming an AND signal of the outputs of each device.