JPS6237433Y2 - - Google Patents

Description

[Detailed description of the invention] The invention relates to an AC-DC converter that converts an AC signal into a DC signal.For example, when controlling the voltage of equipment such as an induced voltage regulator or slider in an AC circuit, hunting is a problem. This makes it suitable for quickly detecting the control amount without any trouble.

Conventionally, there has been a conversion device of this type as shown in FIG. In the figure, reference numeral 1 denotes a rectifier circuit composed of four diodes, which inputs and rectifies a wide range single-phase AC signal (0 to 5 V) to be detected, and outputs a rectified output 3. 4 and 5 are a series body of resistors connected in parallel to the output end of the rectifier circuit 1, which divides the output 3 of the rectifier circuit 1, and a filter capacitor 6 and a filter resistor connected in parallel to the voltage dividing resistor 5. The ripple component is removed from the partial pressure output using a filter constant determined by 4 and converted into a DC signal 7.

Since the conventional AC-DC converter is configured as described above, the output DC signal is affected by the voltage drop caused by the diodes that constitute the rectifier circuit 1, and is also determined by the voltage dividing resistors 6 and 7. can only be converted to a specific value,
Therefore, the detection accuracy is poor for, for example, an AC signal of 0 to 5V to be detected. Furthermore, in the conventional device described above, the alternating current signal is rectified by the rectifier circuit 1 composed of diodes, and ripples are removed by a filter composed of a resistor 4 and a capacitor 6. In order to obtain a small DC signal, it is necessary to use a filter with a very large constant, and if the filter constant is made large, the settling time of the control system becomes longer and the amount of overshoot becomes larger when used in a control system. There was a fear that it would be easily hunted.

The present invention was developed in view of the above points, and by converting a single-phase AC signal into a polyphase AC signal, converting the absolute value of each signal, and adding them together, polyphase full-wave rectification with small ripples is achieved. The rectified waveform is the same as the rectified waveform obtained by the circuit, and the effect of diode drop is removed by absolute value conversion to detect a wide range of single-phase AC signals.It has good linearity, fast response time, and high accuracy. An object of the present invention is to provide an AC-DC converter that can convert a DC signal into a DC signal with a large ripple component and a small ripple component.

Hereinafter, the present invention will be explained based on FIG. 2. In the figure, 8 inputs a single-phase AC signal 2, and from the single-phase AC signal 2, outputs a three-phase AC signal that is different in phase from each other and amplified. This multiphase AC signal generation circuit includes a linear amplifier 9a that amplifies the single-phase AC signal 2 to be detected to a predetermined value, and the amplified linear amplifier 9.
A resistor 10a and a capacitor 11a generate an AC signal with a phase delay of 60 degrees with respect to the AC signal output from a.Similarly, the AC signal output from both ends of the capacitor 11a is adjusted to the same value as the output of the linear amplifier 9a. For the amplifying linear amplifier 9b and the AC signal output from this linear amplifier 9b
Resistor 10b that generates an AC signal with a 60° phase delay
and the capacitor 11b, and the capacitor 11b
The AC signal output from both ends is sent to the linear amplifier 9b.
It is equipped with a linear amplifier 9c that amplifies the output to the same value as the output of the linear amplifier 9c. Therefore, the AC signal output from each linear amplifier 9a, 9b, 9c of this multiphase AC signal generation circuit 8 is 120 in the three-phase AC circuit.
It is similar to a three-phase AC signal with a phase interval of ゜,
The ripple when rectified is much smaller than when a single-phase AC signal is rectified.

Further, reference numeral 12 is an absolute value conversion circuit that converts each AC signal outputted from the multiphase AC signal generation circuit 8 into an absolute value, which is comprised of converters 12a to 12c formed by a plurality of operational amplifiers. 12
a converts the AC signal output from the linear amplifier 9a into an absolute value, and the converter 12b converts the AC signal output from the linear amplifier 9b.
Similarly, the converter 12c converts the AC signal output from the linear amplifier 9c into absolute values.

Since each of the converters 12a to 12c is formed by an operational amplifier 13, the absolute value-converted DC signals output from each of the converters 12a to 12c are added together to generate a ripple signal like the DC signal 14. The DC signal 14 output from the adder circuit 13 is a signal with a small ripple, so it has a small time constant.
A filter consisting of a resistor 15 and a capacitor 16 converts the signal into a DC signal with good linearity, quick response time, and extremely low ripple.

Therefore, according to the configuration shown in FIG. 2, the DC signal 14 obtained by the multiphase AC signal generation circuit 8, the absolute value conversion circuit 12, and the addition circuit 13 is output from the rectifier circuit 1 of the conventional device. Compared to the DC signal 3 that is generated, it goes without saying that there is no effect of the voltage drop caused by the diode, but rather it is amplified, and the ripple is extremely small, so it is necessary to use a filter with a smaller time constant than the conventional device. It is possible to obtain a signal with good linearity, fast response time, and low ripple. Furthermore, detection accuracy for input AC signals can be improved.

In the above embodiment, the multiphase AC signal generation circuit 8 is used to obtain a three-phase AC signal, but as the number of phases increases, the ripple value also decreases, and the AC signal detection accuracy is improved. Of course, it is possible to achieve effects greater than those of the above-mentioned embodiments.

As described above, according to the present invention, the input single-phase AC signal is amplified in the first amplification section, the amplified signal is changed in the phase change section, and the changed signal is transferred to the second amplification section. A polyphase alternating current signal that is amplified to the same value as the output of the first amplification section in the section and changed in the second phase change section, and thereafter outputs a plurality of alternating current signals whose phases are sequentially changed by the same value. a generation circuit, and an absolute value conversion circuit that converts each AC signal output from the multiphase AC signal generation circuit into an absolute value in a corresponding operational amplifier section and outputs a rectified signal;
Since we adopted a configuration that includes an adder circuit that adds up multiple signals output from this absolute value conversion circuit and outputs a DC signal, the amplification section and phase change section are formed with the same capacitance and have the same size. The phase can be changed by sequentially sending the signals, and the resistance value and capacitance of the phase change section can be configured to be small.Furthermore, since the signal is converted to an absolute value in the operational amplifier section, the influence of the voltage drop caused by a conventional diode can be reduced. This has the effect of improving the detection accuracy for AC signals that should be detected without being affected. In addition, a DC signal with good linearity and quick response time and an extremely small ripple component can be obtained.

[Brief explanation of drawings]

FIG. 1 is a circuit connection diagram showing a conventional AC-DC converter, and FIG. 2 is a circuit connection diagram showing an embodiment of the present invention. 2: AC signal, 8: Multiphase AC signal generation circuit, 9
a, 9b, 9c: linear amplifier, 10a, 10
b, 10c: resistor, 11a, 11b: capacitor, 12: absolute value conversion circuit, 13: addition circuit, 1
5: Resistor, 16: Capacitor. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Scope of utility model registration request] A single-phase AC signal is input, and the single-phase AC signal is input to the first
The amplified signal is amplified by the amplifying section, the amplified signal is changed by the phase changing section, and the changed signal is amplified by the second amplifying section to the same value as the output of the first amplifying section. A multiphase AC signal generation circuit that outputs a plurality of AC signals whose phases are changed by a phase changer of Equipped with an absolute value conversion circuit that outputs a signal converted into an absolute value and rectified by a corresponding operational amplifier section, and an addition circuit that adds a plurality of signals output from this absolute value conversion circuit and outputs a DC signal. An AC-DC converter characterized by: