JPS5855682B2 - 3 Souhatsushinki - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a three-phase oscillator used as a command unit of a cycloconverter, etc., and its purpose is to provide a three-phase oscillator that can obtain three-phase alternating current with a frequency proportional to an input signal. There is something to do.

Conventionally, one-phase oscillators with variable frequency and sine wave output have been seen, but three-phase variable frequency oscillators have rarely been used.

A generally known three-phase oscillator uses a phase delay of an R-C circuit, and the oscillation frequency is fixed.

The present invention is characterized by a combination of an l-phase triangular wave variable frequency oscillator and a hysteresis comparator, and an embodiment thereof will be described below with reference to the drawings.

Figure 1 is a circuit diagram of the embodiment, Figure 2 is its block diagram,
1 is a first triangular wave oscillator consisting of an electronic switch 1as, an integrator 1b and a comparator 1c; 2 is an electronic switch 2a, an integrator 2b, a hysteresis comparator 2c and a phase inversion amplifier 2;
A second triangular wave oscillator consisting of c', 3 and 4 waveform shaping circuits consisting of linear function approximation circuits, and 5 an inverting adder.

The electronic switches 1a and 2a are electronic switches that switch the polarity of the input signal in accordance with the signal from the comparator, and the hysteresis comparator 2c is an arithmetic amplifier that has a range of set values, as is well known. For example, when a triangular wave signal is input as the input signal as shown in the lower left figure of Fig. 3, a rectangular signal with hysteresis as shown in the upper left figure is output according to the input signal, If this hysteresis width (among the set values) is widened as shown by the dashed line, the phase of the comparator output will shift.

Further, the linear function approximation circuits 3 and 4 are amplifiers having an input/output relationship as shown in FIG.

Note that the first triangular wave oscillator may be of any other circuit type that has already been found in literature.

Now, when a command signal is given by the frequency setter 6 consisting of a variable resistor that determines the oscillation frequency of the first and second triangular wave oscillators 1 and 2, a signal as shown in FIG. 5A is generated from the electronic switch 1a. outputs.

This output signal is integrated by an integrator 1b and converted into a triangular wave as shown by the solid line in the diagram.

In this case the electronic switch 1a is controlled by the output of the comparator 1c.

The output of the integrator 1b, that is, the triangular wave oscillator 1, is waveform-shaped into a sine wave by the linear function approximation circuit 3 and sent to the output terminal CH.
7, the signal is input to the hysteresis comparator 2c, and is again converted into a rectangular waveform as shown in FIG. 5-2.

The electronic switch 2a, which is controlled by the output signal of the hysteresis comparator 2c, shifts the phase of the command signal by 120 degrees from the output signal of the electronic switch 1a, as shown in FIG.
゜Convert to a signal with a phase shift.

Then, the signal is converted into a triangular wave by the integrator 2b as in the case of the first triangular wave oscillator 1.

That is, the second triangular wave oscillator 2 sends out a triangular wave signal whose phase is delayed by 120 degrees from the output signal of the first triangular wave oscillator 1, and this signal is waveform-shaped by the linear function approximation circuit 4. A signal as shown in FIG. 5H will be sent from the output terminal CH9.

On the other hand, the output signals of the fold line function approximation circuits 3 and 4 are added by an inverting adder 5, and a signal as shown in FIG. A sinusoidal three-phase alternating current is obtained.

The circuit consisting of the diodes 9D to 12D and the Zener diode 3ZD in the circuit shown in FIG. This is a circuit to always center the operation level of 2b at Ov, and also to keep the operation level of diodes 1D to 4D and
The circuit consisting of the ZD generates the first triangular wave oscillator 1 by making the absolute values of the positive and negative sides of the output of the comparator 1c equal.
This circuit sets the center of the operation level to Ov.

Although this example shows an example of a three-phase sine wave AC oscillator, if other waveform shaping circuits are used in place of the linear function approximations 3 and 4, three-phase oscillators with rectangular waves, triangular waves, trapezoidal waves, etc. can be created. There is no need to explain that this can be obtained.

As explained above, according to this invention, by simple stealing,
Since a three-phase oscillator with variable oscillation frequency is obtained, its field of application is extremely diverse.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram of an embodiment of the present invention, Fig. 2 is a block diagram thereof, Fig. 3 is an explanatory diagram of the operation of the hysteresis comparator, Fig. 4 is an explanatory diagram of the operation of the broken line function approximation circuit, and Fig. 5 is FIG. 3 is a waveform diagram for explaining the operation of the example circuit. 1...First triangular wave oscillator, 1a and 2b...
...Electronic switch, 1b and 2b...Integrator, 1c...Comparator, 2...Second 3
Angular wave oscillator, 2c...Hysteresis comparator, 2
0'... Phase inversion amplifier, 3 and 4...
・Folded line function approximation circuit (waveform shaping circuit), 5...
Inverting adder.

Claims (1)

[Claims] 1 First triangular wave generation circuit, its output signal and 120°
a hysteresis comparator that generates a signal with a phase difference; and a second triangular waveform that generates a signal that has a 120° phase difference with the triangular wave output signal of the first triangular wave generation circuit based on the output signal of the hysteresis comparator. a wave generation circuit, two waveform shaping circuits that shape the output signal of the second triangular wave generation circuit and the output signal of the first triangular wave generation circuit, and outputs of the two waveform shaping circuits. A three-phase oscillator characterized by being equipped with an inverting adder that adds signals.