WO2020065816A1

WO2020065816A1 - Comparison circuit, zero-point detection circuit, ac power regulator, and signal comparison method

Info

Publication number: WO2020065816A1
Application number: PCT/JP2018/035897
Authority: WO
Inventors: 茂文後藤; 裕久吉川
Original assignee: 理化工業株式会社
Priority date: 2018-09-27
Filing date: 2018-09-27
Publication date: 2020-04-02
Also published as: JPWO2020065816A1

Abstract

A comparison circuit for outputting the result of a high/low comparison of a reference signal and a comparison signal is provided with: two hysteresis comparators 2A and 2B; input circuits 1A and 1B that each input a reference signal and a comparison signal to the two hysteresis comparators 2A and 2B, respectively; bias circuits 3A and 3B that apply different biases to the reference signals input to the two hysteresis comparators 2A and 2B; and an output circuit 5 which inverts an output signal from High to Low or from Low to High on the basis of an output inversion from High to Low of one of the two hysteresis comparators 2A and 2B, and which inverts the output signal from Low to High or from High to Low on the basis of an output inversion from Low to High of the other hysteresis comparator. Thus, the comparision circuit is configured to produce no delay in the comparison result.

Description

Comparison circuit, zero point detection circuit, AC power regulator, and signal comparison method

The present invention relates to a comparison circuit, a zero point detection circuit, an AC power regulator, and a signal comparison method.

In various electric and electronic circuits, the magnitudes of various signals are compared in the processing operation, and a comparison circuit is provided for the comparison.
As an example of such a comparison circuit, there is a zero point detection circuit for detecting a zero cross point of an AC power supply. The zero point detection circuit is used, for example, in an AC power regulator that adjusts the voltage of a commercial AC power supply by a phase control method and supplies the voltage to a load.
Patent Document 1 discloses a technique for more accurately detecting a zero-cross point in such a phase control type AC power regulator.

JP 2011-39648 A

In the comparison of signals in the comparison circuit, it is desirable that malfunction does not occur even when the signal is distorted from an ideal waveform due to the influence of noise or the like.
As a countermeasure against such noise, for example, a filter circuit for removing noise is provided. When a comparator is used as the comparison circuit, a comparator with hysteresis is used.
However, when a filter circuit is provided, there is a problem that the phase of a signal is delayed by the filter circuit, and the detection of a zero cross point is delayed in a zero point detection circuit or the like. Although it is possible to adopt a circuit configuration in which the phase is not delayed, there is a problem that the circuit becomes complicated and the cost increases. Further, even when a comparator with hysteresis is used, there is a problem that detection of a zero-cross point in a zero-point detection circuit or the like is delayed according to the hysteresis width.

The present invention has been made in view of the above circumstances, and is a comparison circuit for comparing the magnitudes of signals. The comparison circuit can prevent a delay from occurring in the comparison result and has a relatively simple circuit configuration. , A zero point detection circuit, an AC power regulator, and a signal comparison method.

(Configuration 1)
A comparison circuit that outputs a comparison result of a level of a reference signal and a comparison signal, wherein the two input circuits input the reference signal and the comparison signal to each of the two hysteresis comparators; The output signal is changed from High to Low or from Low to High based on a bias circuit for applying a different bias to the reference signal input to the hysteresis comparator and the output inversion of one of the two hysteresis comparators from High to Low. An output circuit that inverts the output signal from Low to High or from High to Low based on the output inversion of the other hysteresis comparator from Low to High.

(Configuration 2)
2. The comparison circuit according to Configuration 1, wherein a positive bias is applied to a reference signal input to one of the hysteresis comparators, and a negative bias is applied to a reference signal input to the other hysteresis comparator.

(Configuration 3)
3. The comparison circuit according to Configuration 2, wherein the absolute value of the positive bias is substantially the same as the absolute value of the negative bias.

(Configuration 4)
A comparison circuit that outputs a comparison result of a level of a reference signal and a comparison signal, wherein the two input circuits input the reference signal and the comparison signal to each of the two hysteresis comparators; The output signal is changed from High to Low or from Low to High based on a bias circuit for applying a different bias to the comparison signal input to the hysteresis comparator and the output inversion of one of the two hysteresis comparators from High to Low. An output circuit that inverts the output signal from Low to High or from High to Low based on the output inversion of the other hysteresis comparator from Low to High.

(Configuration 5)
The comparison circuit according to Configuration 4, wherein a plus bias is applied to the comparison signal input to the one hysteresis comparator, and a minus bias is applied to the comparison signal input to the other hysteresis comparator.

(Configuration 6)
The comparison circuit according to Configuration 5, wherein the absolute value of the plus bias is substantially the same as the absolute value of the minus bias.

(Configuration 7)
The comparison circuit according to any one of Configurations 1 to 6, wherein the absolute value of the bias is approximately half the hysteresis width of the hysteresis comparator.

(Configuration 8)
A zero point detection circuit that performs zero point detection of an AC power supply waveform by using the comparison circuit according to any one of Configurations 1 to 7, setting the reference signal to a zero point, and using the comparison signal as an AC power supply waveform signal.

(Configuration 9)
The zero point detection circuit according to Configuration 8, an output target value trigger angle conversion unit for converting an output target value to a trigger angle, and the trigger based on a zero crossing point of the AC power supply waveform detected by the zero point detection circuit. An AC power regulator, comprising: a trigger angle output unit that outputs an angle; and a thyristor control unit that controls a thyristor based on the trigger angle.

(Configuration 10)
A comparison method for outputting a comparison result of a level of a reference signal and a comparison signal, wherein two hysteresis comparators are used to input the reference signal and the comparison signal to each of the two hysteresis comparators. Applying a different bias to the reference signal input to the hysteresis comparator, and inverting the output signal from high to low or from low to high based on the output inversion of one of the two hysteresis comparators from high to low. And inverting the output signal from low to high or from high to low based on the output inversion of the other hysteresis comparator from low to high.

(Configuration 11)
A comparison method for outputting a comparison result between a reference signal and a comparison signal, wherein two hysteresis comparators, the reference signal and the comparison signal are input to each of the two hysteresis comparators, and the two hysteresis comparators Applying a different bias to the comparison signal input to the comparator, and inverting the output signal from high to low or from low to high based on the output inversion of one of the two hysteresis comparators from high to low. And inverting the output signal from Low to High or from High to Low based on the output inversion of the other hysteresis comparator from Low to High.

According to the comparison circuit of the present invention, it is possible to provide a comparison circuit capable of preventing a delay in the comparison result with a relatively simple circuit configuration.

1 is a schematic block diagram illustrating a configuration of an AC power regulator according to an embodiment of the present invention. FIG. 2 is a diagram illustrating a configuration of a zero-point detection circuit (comparison circuit) according to the embodiment. The flowchart which shows the outline of the processing operation of the microcomputer (output circuit) with which the zero point detection circuit (comparison circuit) is provided Explanatory drawing for explaining the operation of the zero point detection circuit (comparison circuit) Explanatory diagram for explaining a conventional problem in zero point detection Diagram showing the configuration of the comparison circuit Explanatory diagram for explaining another operation example of the zero point detection circuit (comparison circuit)

Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings. Note that the following embodiment is one mode for embodying the present invention, and does not limit the present invention within the scope thereof.

FIG. 1 is a block diagram schematically illustrating a configuration of an AC power regulator according to Embodiment 1 of the present invention. The AC power regulator 100 of the present embodiment is an AC power regulator that controls power supply to a load by phase control. More specifically, the AC power regulator 100 switches the switch 600 (for example, a relay or a breaker) and the fuse 60 based on a target value input from a controller (temperature controller) 200 which is an external device. By controlling the thyristor 50 connected to the AC power supply 500 via the AC power supply, the power supplied to the primary side of the transformer 400 is adjusted by phase control, and the power supply from the AC power supply 500 to the heater of the controlled object 300 is controlled. Is what you do.
In the present embodiment, an example is shown in which the thyristor 50 is mounted as a switching element. However, the present invention is not limited to this. For example, a triac may be mounted as a switching element.

The AC power regulator 100 includes a zero point detection unit 10 for detecting a zero point of an AC power supply waveform, an output target value trigger angle conversion unit 20 for converting an output target value to a trigger angle, and an AC detected by the zero point detection unit 10. A trigger angle output unit 30 that outputs a trigger angle based on a zero-cross point of the power supply waveform, a thyristor control unit 40 that controls a thyristor based on the trigger angle, and an AC power supply 500 that receives a timing of the firing angle and the zero-cross point. A thyristor 50 that switches power supply to the heater of the control target 300 and a fuse 60 are provided.
The phase control method in the AC power regulator 100 and the configuration therefor are the same as the conventional AC power regulator except for the zero point detection unit 10, so that a further detailed description is omitted here. Mainly, the zero point detecting unit 10 will be described.
In FIG. 1, the configuration is described separately for each function. However, it does not necessarily indicate that the configuration is divided into hardware. For example, a known general-purpose device such as a PLC, an MCU, or a microcomputer may be used. Each configuration may be implemented as software by using. Of course, each component may be configured as hardware, for example, may be configured using an FPGA or the like, or may be configured as dedicated hardware using an ASIC or the like.

FIG. 2 is a diagram illustrating a circuit configuration (zero point detection circuit) of the zero point detection unit 10.
The zero point detection unit (zero point detection circuit) 10 inputs two

hysteresis comparators

2A and 2B, and a reference signal (zero point) and a comparison signal (AC power supply waveform signal) to each of the two

hysteresis comparators

2A and 2B. The

input circuits

1A and 1B, the bias circuits 3A and 3B for applying different biases to the reference signals (zero points) input to the two

hysteresis comparators

2A and 2B, and one of the two hysteresis comparators from High to Low. An output circuit that inverts the output signal from High to Low or Low to High on the basis of the output inversion to, and inverts the output signal from Low to High or from High to Low based on the output inversion from the other hysteresis comparator Low to High. Is a microcomputer Comprises a Tsu bets 5, the level adjusting circuit 4A of the input signal to the microcomputer unit 5 (hysteresis comparator 2A, the output signal from 2B), and 4B, the.

The resistors R1A, R2A (R1B, R2B) provided in the input circuit 1A (1B) are voltage dividing circuits for adjusting the amplitude of the AC power supply 500 to an appropriate level as an input to the hysteresis comparator 2A (2B). (In this embodiment, the amplitude is adjusted to ± 4 V).
The resistors R3A, R4A (R3B, R4B) provided in the hysteresis comparator 2A (2B) are voltage dividing circuits for adjusting the hysteresis width. In the present embodiment, the hysteresis width of each of the

hysteresis comparators

2A and 2B is 2V.

The resistors R4A, R5A (R4B, R5B) provided in the bias circuit 3A (3B) are voltage dividing circuits for adjusting a bias amount.
In the present embodiment, the power supply line of +5 V is connected to the bias circuit 3A, and the reference signal (zero point = 0 V) input to the comparator A is biased by +1 V by the voltage dividing circuit of the resistors R4A and R5A. Thereby, as shown in FIG. 4, the lower end of the hysteresis of the hysteresis comparator 2A becomes zero point = 0V, and the upper end becomes + 2V.
On the other hand, a -5V power supply line is connected to the bias circuit 3B, and a reference signal (zero point = 0V) input to the comparator B is biased by -1V by a voltage dividing circuit of resistors R4B and R5B. Thereby, as shown in FIG. 4, the lower end of the hysteresis of the hysteresis comparator 2B becomes -2V, and the upper end becomes the zero point = 0V.
That is, a positive bias is applied to the reference signal input to one hysteresis comparator, and a negative bias is applied to the reference signal input to the other hysteresis comparator. Further, the absolute value of the positive bias is substantially the same as the absolute value of the negative bias, and the absolute value of the bias is substantially １／ of the hysteresis width of the hysteresis comparator.

The level adjustment circuit 4A (4B) is connected to a + 5V power supply line, and is input to the microcomputer unit 5 (output signals from the

hysteresis comparators

2A and 2B) by a voltage divider circuit of resistors R6A and R7A (R6B and R7B). Is adjusted to an appropriate value (in this embodiment, High = 5V and Low = 0V).

Next, the processing operation of the microcomputer unit 5 which receives the input from the

hysteresis comparators

2A and 2B by the circuit having the above configuration will be described with reference to the flowchart of FIG.
The processing of steps 301 to 304 is a loop processing that repeatedly operates while detecting the zero-cross point of the AC power supply 500.
In step 301, it is monitored whether or not the signal from the hysteresis comparator 2A has changed from low to high. If the signal has changed from low to high, the process proceeds to step 303. In step 303, the output from the output terminal 6 is inverted from Low to High.
In step 302, it is monitored whether or not the signal from the hysteresis comparator 2B has changed from High to Low. If the signal has changed from High to Low, the process proceeds to Step 304. In step 304, the output from the output terminal 6 is inverted from High to Low.
By repeating the above processing, a signal in which High and Low are inverted at the zero cross point of the AC power supply 500 without delay is output from the output terminal 6.

FIG. 4 is an explanatory diagram for explaining the operation of the zero point detection unit (zero point detection circuit) 10.
4 shows the waveform of the AC power supply 500 and the hysteresis of each of the

hysteresis comparators

2A and 2B, and the lower side of FIG. 4 shows the output waveforms of the

hysteresis comparators

2A and 2B and the microcomputer unit 5 (output terminal 6). 3 shows an output waveform from the oscilloscope.

As shown in FIG. 4, in the hysteresis comparator 2A, the upper end of the hysteresis is + 2V, while the lower end of the hysteresis is zero point = 0V. Accordingly, the output waveform of the hysteresis comparator 2A switches between High / Low when the waveform of the AC power supply 500 exceeds + 2V which is the upper end of the hysteresis, and when the waveform of the AC power supply 500 falls below 0V which is the lower end of the hysteresis. Is switched between Low / High. Therefore, when the voltage falls below 0 V which is the lower end side of the hysteresis, the zero cross point is represented without delay.
On the other hand, in the hysteresis comparator 2B, the upper end of the hysteresis is zero point = 0V, while the lower end of the hysteresis is -2V. Accordingly, the output waveform of the hysteresis comparator 2B switches between High / Low when the waveform of the AC power supply 500 exceeds 0V which is the upper end of the hysteresis, and the waveform of the AC power supply 500 falls below -2V which is the lower end of the hysteresis. At this time, Low / High is switched. Therefore, when the voltage exceeds 0 V, which is the upper end of the hysteresis, the zero cross point is represented without delay.
In the microcomputer unit 5, the low / high switching when the waveform of the AC power supply 500 in the hysteresis comparator 2A falls below 0V, which is the lower end side of the hysteresis, and the processing of the AC power supply 500 in the hysteresis comparator 2B are performed by the processing of FIG. A signal for switching between High and Low is output from the output terminal 6 based on the switching between High and Low when the waveform exceeds 0 V, which is the upper end of the hysteresis.
Therefore, the output from the output terminal 6 has a waveform representing the zero-cross point of the AC power supply 500 without delay.

As described above, according to the zero point detection unit (zero point detection circuit) 10 in the AC power regulator 100 of the present embodiment, the zero cross point of the AC power supply 500 can be detected without delay. Further, a circuit capable of detecting the zero-cross point without delay and reducing the influence of noise can be realized with a relatively simple circuit configuration.

FIG. 5 is a diagram for explaining a problem that occurs in the conventional AC power regulator 100 due to a certain delay in measuring the zero-cross point of the AC power supply.
As shown in FIG. 5A, when the power supply waveform of the AC power supply is a normal waveform, even if the circuit configuration has a certain delay in the measurement of the zero-cross point, the delay time is subtracted. There is no problem if processing is performed. That is, there is no problem if the call timing of the trigger point is calculated from the time point at which the (n-1) -th zero point is detected, taking into account the delay time of the zero point detection.
However, for example, in one phase of a three-phase AC power supply, a phenomenon may occur in which the phase of the power supply waveform is temporarily advanced due to the influence of power supply of another phase.
FIG. 5B shows a situation in which the phase of the power supply waveform has advanced in this manner.
In FIG. 5B, the trigger point is set at the same timing as in FIG. 5A, but as a result of the advance of the phase of the power supply waveform, in FIG. 5B, the zero-cross point comes before the trigger point. The device cannot determine whether the phase is advanced or not, and, as in FIG. 5A, triggers after taking into account the delay time of zero point detection from the time point at which the (n-1) th zero point is detected. This is because the points are set.
As a result, a large power supply may occur where a small power supply is originally required. If the output becomes excessive, an excessive rush current flows due to the magnetic saturation of the transformer, which may cause a problem that the fuse is blown or the transformer is damaged.
When a certain delay occurs in the measurement of the zero-cross point of the AC power supply, it is difficult to detect the instantaneous phase shift before the arrival of the trigger point as shown in FIG. It is difficult to deal with such problems.
On the other hand, according to the zero point detection unit (zero point detection circuit) 10 in the AC power regulator 100 of the present embodiment, the zero cross point of the AC power supply 500 can be detected without delay as described above. It is also possible to deal with such a problem.

In this embodiment, as shown in FIG. 4, the output signal of the hysteresis comparator 2A (2B) switches from High to Low when the waveform of the AC power supply 500 exceeds the upper end of the hysteresis. When the waveform falls below the lower end of the hysteresis, the signal changes from low to high. In the microcomputer unit 5, the output signal changes from low to high in response to the switching from low to high in the hysteresis comparator 2A, and changes from high to low in the hysteresis comparator 2B. An example in which the output signal is switched from High to Low according to the switching of Low is described as an example, but the difference between High and Low in each signal can be changed as appropriate. That is, for example, High and Low of each output waveform on the lower side of FIG. 4 may be inverted (arbitrary combinations are possible, such as inverting all or inverting only one of the output waveforms). .

In the present embodiment, the zero point detection circuit in the AC power regulator has been described as an example. However, the present invention is not limited to this, and a comparison circuit that outputs a comparison result of the level of a reference signal and a comparison signal, a signal comparison method Can be widely used as.
That is, as shown in FIG. 6, a comparator circuit 12 having two hysteresis comparators and

input terminals

111 and 112 to which a reference signal and a comparison signal are input are provided. (Which terminal receives the reference signal is arbitrary. ) An input circuit 11 for inputting a reference signal and a comparison signal to each of the two hysteresis comparators, a bias circuit 13 for applying different biases to the reference signals input to the two hysteresis comparators, and one of the two hysteresis comparators The output signal is inverted from High to Low or from Low to High based on the output inversion of the hysteresis comparator from High to Low, and the output signal is output from Low to High or High based on the output inversion of the other hysteresis comparator from Low to High. Low An output circuit 15 for inverting, by the comparison circuit comprising a can compare any signals.
In the present embodiment, the output circuit is configured as software on the microcomputer unit 5 as an example. However, the output circuit may be configured as hardware using a dedicated circuit or the like.

In the present embodiment, an example is given in which a bias is applied to a reference signal, but a bias may be applied to a comparison signal.
Further, in the present embodiment, a plus bias is applied to the signal input to one hysteresis comparator, and a minus bias is applied to the signal input to the other hysteresis comparator, so that the absolute values of the plus and minus biases are substantially the same. And the bias is approximately の of the hysteresis width. However, the present invention is not limited to this, and the absolute values of the positive and negative biases are different, and the bias is input to both hysteresis comparators. It may be possible to apply a plus (or minus) bias to such a signal.
In addition, in the present embodiment, with the above configuration, the upper end of the hysteresis of one hysteresis comparator and the lower end of the hysteresis of the other hysteresis comparator are the same, but some regions of both hysteresis overlap. Or may be such that there is an interval between both hysteresis.
The above points can be appropriately selected according to the signal to be compared and the purpose thereof.
For example, FIG. 7 shows a case where an interval is provided between both hysteresis in a zero point detection circuit similar to the embodiment. As can be understood from the figure, a point earlier than the actual zero-cross point is detected by setting both hysteresis positions at intervals above and below the zero point (the output of High / Low is inverted). Will be). Depending on the application, it may be desirable to detect a point slightly earlier than the actual zero-cross point, and it is possible to meet such a demand.

100. . . AC power regulator 10. . . Zero point detection unit (zero point detection circuit, comparison circuit)
1A, 1B. . .

Input circuits

2A, 2B. . . Hysteresis comparator 3A, 3B. . . Bias circuit 5. . . Microcomputer unit (output circuit)
20. . . Output target value trigger angle conversion unit 30. . . Trigger angle output unit 40. . . Thyristor control unit 50. . . Thyristor

Claims

A comparison circuit that outputs a comparison result of the level of the reference signal and the comparison signal,
Two hysteresis comparators,
An input circuit for inputting the reference signal and the comparison signal to each of the two hysteresis comparators;
A bias circuit for applying different biases to the reference signals input to the two hysteresis comparators;
The output signal is inverted from High to Low or from Low to High based on the output inversion from High to Low of one of the two hysteresis comparators, and based on the output inversion from Low to High on the other hysteresis comparator. An output circuit for inverting the output signal from Low to High or from High to Low;
A comparison circuit comprising:
2. The comparison circuit according to claim 1, wherein a positive bias is applied to the reference signal input to one of the hysteresis comparators, and a negative bias is applied to the reference signal input to the other hysteresis comparator.
3. The comparison circuit according to claim 2, wherein the absolute value of the positive bias is substantially equal to the absolute value of the negative bias.
A comparison circuit that outputs a comparison result of the level of the reference signal and the comparison signal,
Two hysteresis comparators,
An input circuit for inputting the reference signal and the comparison signal to each of the two hysteresis comparators;
A bias circuit for applying different biases to comparison signals input to the two hysteresis comparators;
The output signal is inverted from High to Low or from Low to High based on the output inversion from High to Low of one of the two hysteresis comparators, and based on the output inversion from Low to High on the other hysteresis comparator. An output circuit for inverting the output signal from Low to High or from High to Low;
A comparison circuit comprising:
5. The comparison circuit according to claim 4, wherein a plus bias is applied to the comparison signal input to the one hysteresis comparator, and a minus bias is applied to the comparison signal input to the other hysteresis comparator.
6. The comparison circuit according to claim 5, wherein the absolute value of the positive bias is substantially equal to the absolute value of the negative bias.
7. The comparison circuit according to claim 1, wherein the absolute value of the bias is substantially half the hysteresis width of the hysteresis comparator.
A zero point detection circuit that performs zero point detection of an AC power supply waveform by using the comparison circuit according to any one of claims 1 to 7, wherein the reference signal is a zero point, and the comparison signal is an AC power supply waveform signal. .
A zero point detection circuit according to claim 8,
An output target value trigger angle conversion unit for converting an output target value into a trigger angle,
A trigger angle output unit that outputs the trigger angle based on a zero point of the AC power supply waveform detected by the zero point detection circuit,
A thyristor control unit that controls a thyristor based on the trigger angle;
An AC power regulator comprising:
A comparison method for outputting a high / low comparison result of a reference signal and a comparison signal,
Using two hysteresis comparators,
Inputting the reference signal and the comparison signal to each of the two hysteresis comparators;
Applying different biases to the reference signals input to the two hysteresis comparators;
The output signal is inverted from High to Low or from Low to High based on the output inversion from High to Low of one of the two hysteresis comparators, and based on the output inversion from Low to High on the other hysteresis comparator. Inverting the output signal from Low to High or from High to Low;
A signal comparison method comprising:
A comparison method for outputting a high / low comparison result of a reference signal and a comparison signal,
Two hysteresis comparators,
Inputting the reference signal and the comparison signal to each of the two hysteresis comparators;
Applying different biases to the comparison signals input to the two hysteresis comparators;
The output signal is inverted from High to Low or from Low to High based on the output inversion from High to Low of one of the two hysteresis comparators, and based on the output inversion from Low to High on the other hysteresis comparator. Inverting the output signal from Low to High or from High to Low;
A signal comparison method comprising: