JPH08286772A - Power controller and power supply unit - Google Patents

Abstract

PURPOSE: To stabilize output without making output power unstable due to noise and the like by reducing output power without reducing the conductive angle of a thyristor at the time of slight output when small output power is requested. CONSTITUTION: At the time of slight output in the case of a conventional power controller, the conductive angle θ2 of a triac 25 is required to be small. In the case of this power controller 23a, output power is controlled and micro output can be obtained by reducing (or enlarging a non-conductive angle) the number of the turning-on times of the triac 25 without reducing the conductive angle so much, and therefore output can be stabilized even in the case of micro output. furthermore, a DC component is prevented from being contained, the controller can deal with the case of a load 24 which requires AC power can be realized and the verification of output is facilitated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power control device and a power supply device. In particular, the present invention relates to a power control device and a power supply device that use a thyristor to control the phase angle of output power or output voltage or output current of an AC power supply.

[0002]

2. Description of the Related Art For example, electric power for controlling electric power (power consumption) or voltage (load voltage) or current (load current) [hereinafter, simply referred to as electric power] output to a heating portion such as a heater, electric heating equipment, or other loads. In the control device and the power supply device, the output of the AC power supply is controlled by phase angle control using a thyristor such as a triac (TRIAC; bidirectional three-terminal thyristor) or SCR (reverse blocking three-terminal thyristor). .

(Conventional AC full-wave control system) An example of such a power supply device (power supply device) 1A is shown in FIG. In this power supply device 1A, the power of the AC power supply 2 is supplied to the load 4 via the power control device 3a, and the power supplied to the load 4 is controlled by the power control device 3a. This power control device 3a is an AC full-wave control system using a triac 5, and is composed of a zero-cross point detection circuit 6, a pulse generation circuit 7, a trigger circuit 8 and a triac 5.

The triac 5 includes an AC power source 2 and a load 4.
It is connected in series with AC power supply 2 and triac 5
The load circuit is configured by the load 4 and the load 4, and the load circuit can be opened and closed by turning the triac 5 off and on.

The zero-cross point detection circuit 6 is connected to one output of the AC power supply 2 and detects the zero-cross point of the AC power output (AC power voltage). That is, FIG. 2 (a)
Is a waveform diagram showing an AC power supply output 9. The zero-cross point detection circuit 6 detects the AC power supply output 9 and full-wave rectifies the AC power supply output 9 to obtain a full-wave rectified waveform as shown in FIG. 2B. 1
Get 0. Then, this full-wave rectified waveform 10 is compared with a predetermined threshold value Vth, and a zero-crossing detection pulse 11 is output in a region where the voltage is smaller than the threshold value Vth (FIG. 2).
(C)). The zero-cross detection pulse 11 is output to the pulse generation circuit 7, and the pulse generation circuit 7 uses the falling operation of the zero-cross detection pulse 11 as a zero-cross point detection signal. The zero-cross point detection method in the zero-cross point detection circuit 6 is the same as the original AC power supply output 9
It may be compared with two threshold values Vth and -Vth.

Thus, as shown in FIGS. 3A and 3B, the zero-cross point detection circuit 6 detects the zero-cross point of the AC power supply output 9, and the pulse generation circuit 7 receives the zero-cross point detection signal 12 (zero-cross detection pulse 11). (Falling operating point) of the pulse generator circuit 7 shown in FIG.
As shown in (c), a pulse signal 13 having a predetermined pulse width Tw is output in synchronization with the zero-cross point detection signal 12. When the pulse signal 13 is output from the pulse generation circuit 7 to the trigger circuit 8, the trigger signal 14 is output from the trigger circuit 8 to the triac 5 in synchronization with the falling operation of the pulse signal 13 (FIG. 3 (d)). . When the trigger signal 8 is output from the trigger circuit 8, the triac 5 is turned on and becomes conductive, so that the load current 15 flows and power is supplied to the load 4. Then, AC power output 9
When the voltage of 0 becomes 0 volt (zero cross point), the triac 5 is turned off again and becomes non-conductive. As a result,
The timing of turning on (conducting) and turning off (non-conducting) the triac 5 is as shown in FIG. 3 (e), and the waveform of the load current 15 (in the case of a resistive load) is as shown in FIG. 3 (f).

In the case of the phase angle control, since the operation of the thyristor, the change of the load current and the like are usually expressed by the phase angle of the AC power supply output, the control angle (trigger phase angle) θ ₁ used in the following will be used. , Non-conduction angle α and conduction angle θ ₂ are defined (see FIG. 3 (f), FIG. 5 (f), etc.). Control angle θ
₁ is the phase angle from the moment the thyristor turns on to the zero cross point immediately before it. AC power output 1
Since the cycle has a phase angle of 2π radians (hereinafter, the unit of the phase angle is expressed in radians, and the unit is omitted), the phase angle between the zero cross points is π. Therefore, the control angle θ ₁ is 0 ≦ θ ₁ ≦ π. The conduction angle θ ₂ is a phase angle in a section in which the thyristor is in a continuous conduction state. Since the conducting thyristor is turned off at the next zero cross point, the conducting angle θ ₂ is 0 ≦ θ ₂ ≦ π. Further, there is a relationship of θ ₂ = π−θ ₁ between the control angle θ ₁ and the conduction angle θ ₂ . The non-conduction angle α is a phase angle in a section in which the thyristor is continuously in the non-conduction state.

To explain the AC full-wave control system of FIG. 3 again in terms of phases, zero-cross points are detected at a cycle of every phase π (FIG. 3 (b)), and the trigger signal 14 is detected from each zero-cross point. Is output for each phase π with a delay of the control angle θ ₁ (FIG. 3 (d)). Therefore, the triac 5 is turned on every time with a delay of the control angle θ ₁ from the zero cross point,
A load current 15 is passed through the load circuit and turned off at the next zero-cross point to cut off the load current 15 (Fig. 3 (e)).
(F)). Therefore, the power output from the AC power supply 2 to the load 4 can be controlled by changing the control angle θ ₁ determined by the pulse width Tw of the pulse signal 13 generated by the pulse generation circuit 7.

However, as is apparent from the above operation, this conventional AC full-wave control type power control device has the following features or restrictions. The trigger signal is output each time the zero-cross point is detected, and the cycle of the trigger signal and the cycle (π) of the zero-cross point are equal. Since the non-conduction angle α is equal to the control angle θ ₁ , the non-conduction angle α (= θ ₁ = π−θ ₂ ) is smaller than π. The thyristor is turned on each time the zero cross point is detected. Therefore, when the electric power to be output (for example, effective value, peak value, average value) is extremely small, as shown in FIG. 3 (g), the control angle θ ₁ is brought close to π and the conduction angle θ _{2 is set.} Had to be very small.

(Conventional AC Half-Wave Control System) Next, the conventional AC half-wave control system power control device 3b used in the power supply device 1B of FIG. 4 will be described. That is, in the current control device 3b, the SC is provided between the AC power supply 2 and the load 4.
The R16 is connected and the load circuit is opened and closed by the SCR16.

Also in the current control device 3b, the zero-cross point detection circuit 6 detects the zero-cross point of the AC power supply output 9 of FIG. 5A, and the zero-cross point detection signal 12 is output for each phase π ( FIG. 5B). When the zero-cross point is detected by the zero-cross point detection circuit 6, the pulse signal 13 having the pulse width Tw is output from the pulse generation circuit 7 (FIG. 5C), and the trigger circuit is synchronized with the falling operation of the pulse signal 13. The trigger signal 14 is output from 8 at a cycle of every phase π (FIG. 5D). Therefore, FIG.
As shown in (e) and (f), in the case of the forward voltage, the SCR 16 is turned on with a delay of the control angle θ ₁ from the zero cross point, the load current 15 flows in the load circuit, and the SCR 16 is turned on at the next zero cross point. It turns off and the load current 15 is cut off. Further, in the case of the reverse voltage, even if the trigger signal 14 is output from the trigger circuit 8, the SCR 16 does not turn on because the SCR 16 is in the reverse conduction direction, and the load current 15
Does not flow. Therefore, in this AC half-wave control method, the trigger signal 14 is output at the same cycle as the zero-cross point, but the triac is turned on at twice that cycle, and the non-conduction angle α (= π + θ ₁ = 2π− θ ₂ ) is π ≤ α
≦ 2π.

However, as is apparent from the above operation, the conventional AC half-wave control type power control device also has the following features or restrictions. The trigger signal is output each time the zero-cross point is detected, and the cycle of the trigger signal and the cycle (π) of the zero-cross point are equal. Non-conduction angle α is control angle θ
It is larger than ₁ by π, but cannot be larger than 2π. The thyristor is turned on every time the zero-cross point is detected twice, but when the power to be output (for example, effective value, peak value, average value) is extremely small, in the case of the AC full-wave control method as well. In the same manner as above, there was no choice but to make the control angle θ ₁ close to π and make the conduction angle θ ₂ extremely small.

[0013]

As described above, in the power control device of the phase angle control system, very small output power is required in the case of AC full-wave control and AC half-wave control. At the time of very small output, it was necessary to make the conduction angle θ _{2 of the} thyristor extremely small. Therefore, there is a problem that the instantaneous value or the peak value of the output power becomes small and the output becomes unstable due to noise or the like. In addition, when the conduction angle θ ₂ becomes small and approaches the turn-on time and the turn-off time of the thyristor, there is a problem that the control accuracy of the output power deteriorates.

Further, since the control angle θ ₁ and the conduction angle θ ₂ are actually controlled by the time (for example, the pulse width of the pulse signal 13), when the frequency of the AC power source fluctuates during minute output, for example, When a generator is used as an AC power source and the rotation speed of the generator fluctuates, the conduction angle θ ₂ (conduction time) also fluctuates significantly. That is, assuming that the control angle time is constant, the conduction time of the thyristor is small when the difference between the 1/2 cycle (half cycle time) and the control angle time is small, or when the cycle or frequency of the AC power supply output changes. There was a drawback that it fluctuated significantly.

The present invention has been made in view of the above-mentioned drawbacks of the conventional examples, and an object thereof is to reduce the conduction angle of a thyristor in a phase control type power control device or power supply device. In other words, the output power, the output voltage, and the output current can be reduced to improve the output stability during minute output.

[0016]

DISCLOSURE OF THE INVENTION A power control device according to claim 1 is a thyristor for connecting to an AC power source and a load to form a load circuit, and a zero-cross point detecting means for detecting a zero-cross point of an AC power output. A power control device comprising a phase angle control means for outputting a trigger signal for conducting the thyristor at a predetermined control angle from the zero cross point detected by the zero cross point detection means, wherein the phase angle control means is It is characterized in that the trigger signal can be output in a cycle that is a multiple of the cycle of the zero-cross point.

Here, the thyristor is an SCR (reverse blocking three-terminal thyristor), triac (TRIAC; bidirectional three-terminal thyristor) or other thyristor element.

When this power control device is connected to an AC power source, the zero-cross point detection means detects the zero-cross points of the AC power output, and the phase angle control means triggers at a predetermined control angle from the zero-cross points detected every plural times. When a signal is output and the trigger signal is output, the thyristor of the load circuit turns on and becomes conductive until the next zero cross point, and the power is output to the load. As a result, power is supplied to the load at a constant conduction angle, and the power output to the load can be controlled by changing the control angle.

Moreover, in the power control apparatus of the present invention, the trigger signal can be output at a cycle that is a multiple of the cycle of the zero-cross point (that is, a length that is at least twice the cycle).
Therefore, not only can the output power be reduced by reducing the conduction angle of the thyristor in the conducting state, but also the cycle of the trigger signal can be lengthened (lowered in frequency) to reduce the number of conductions per unit time of the thyristor. Can also reduce the output power. That is, at the minute output, the output power can be reduced without reducing the conduction angle.

Here, the embodiment described in claim 2 is, in the power control device according to claim 1, when the output power, the output voltage or the output current is a predetermined value or more,
Output the trigger signal at the same cycle as the zero-cross point,
When the output power, the output voltage, or the output current is less than or equal to a predetermined value, the trigger signal is output in a cycle that is a multiple of the cycle of the zero-cross point.

As described above, when the output power (or the output voltage or the output current) is a minute output of a predetermined value or less, the cycle of the trigger signal is lengthened to reduce the output power without reducing the conduction angle of the thyristor. can do. Further, when the output power is larger than the predetermined value, the output power can be increased while keeping the conduction cycle of the thyristor constant.

According to another aspect of the power control apparatus of the present invention, a thyristor for connecting to an AC power source and a load to form a load circuit, zero-cross point detecting means for detecting a zero-cross point of the AC power output, and a zero-cross point. Phase angle control means for keeping the thyristor in a non-conducting state in a section of a predetermined non-conduction angle with reference to the zero-cross point detected by the point detection means, and conducting the thyristor at the end of the section of the non-conduction angle. In the power control apparatus of the AC full-wave control method, the phase angle control means can set the non-conduction angle to a phase angle larger than π radians.

Here, the AC full-wave control method controls the control angle in both polarities of the output of the AC power supply.

Since this power control device can set the non-conduction angle to a phase angle larger than π radians in the AC full-wave control system, the conduction angle can be reduced to reduce the output power. Alternatively, the output power can be reduced by increasing the non-conduction angle while maintaining the conduction angle at an appropriate level.

The power control device according to a fourth aspect of the present invention is
A thyristor for connecting to an AC power source and a load to form a load circuit, a zero-cross point detecting means for detecting a zero-cross point of the AC power output, and a predetermined control angle from the zero-cross point detected by the zero-cross point detecting means. In the power control apparatus of the AC full-wave control system, the phase angle control means includes a phase angle control means for electrically connecting the thyristor with the phase angle control means for detecting the zero cross point of the AC power supply output twice or more times a predetermined number of times. In addition, the thyristor can be electrically connected.

In this power control apparatus, in the AC full-wave control method, the thyristor is turned on every time the zero-cross point of the output of the AC power source is detected a predetermined number of times twice or more. Compared with the power control device of the wave control method, the number of times of conduction of the thyristor is thinned out, the number of times of conduction per unit time is reduced, and the output power can be reduced without reducing the conduction angle of the thyristor.

Further, the embodiment described in claim 5 is characterized in that, in the power control device according to claim 4, the number of times of detecting the zero cross point for conducting the thyristor is an odd number.

In this embodiment, in the AC full-wave control type power control device, the thyristor is turned on once at the zero-cross point every odd number of times, so that the thyristor is alternately turned on by the positive polarity and the negative polarity of the AC power output. To do. Therefore, according to this power control device, it is possible to obtain an output that does not include a DC component.

According to a sixth aspect of the power control apparatus of the present invention, a thyristor for connecting to an AC power source and a load to form a load circuit, zero-cross point detecting means for detecting a zero-cross point of the AC power output, and a zero-cross point. Phase angle control means for maintaining the thyristor in a non-conducting state in a section of a predetermined non-conduction angle with reference to the zero-cross point detected by the point detection means, and conducting the thyristor at the end of the section of the non-conduction angle. In the AC half-wave control type power control device, the phase angle control means is characterized in that the non-conduction angle can be set to a phase angle larger than 2π radians.

Here, the AC half-wave control method is for controlling the trigger phase angle only in one polarity,
There are cases of only controlled half-waves and cases of combinations of controlled half-waves and uncontrolled half-waves.

Since this power control device can set the non-conduction angle to a phase angle larger than 2π radians in the AC half-wave control system, the conduction angle can be reduced to reduce the output power. Alternatively, the output power can be reduced by increasing the non-conduction angle while maintaining the conduction angle at an appropriate level.

The power control apparatus according to claim 7 is
A thyristor for connecting to an AC power source and a load to form a load circuit, a zero-cross point detecting means for detecting a zero-cross point of the AC power output, and a predetermined control angle from the zero-cross point detected by the zero-cross point detecting means. In the power control apparatus of AC half-wave control method, the phase angle control means includes a phase angle control means for electrically connecting the thyristor with the phase angle control means. In addition, the thyristor can be electrically connected.

In the AC half-wave control system, this power control device makes the thyristor conductive whenever the zero-cross point of the AC power supply output is detected a predetermined number of times twice or more. Compared with the power control device of the wave control method, the number of times of conduction of the thyristor is thinned out, the number of times of conduction per unit time is reduced, and the output power can be reduced without reducing the conduction angle of the thyristor.

The power supply device according to claim 8 comprises an AC power supply and the power control device, and the output value of the power, voltage or current supplied from the AC power supply is controlled by the power control device. It is characterized by having done.

Therefore, in this power supply device, at the time of very small power output, the output power can be reduced without reducing the conduction angle of the thyristor used in the power control device, and the output is stabilized. be able to.

[0036]

【Example】

(First Embodiment) FIG. 6 is a circuit diagram (functional block diagram) showing a power supply device (power supply device) 21A according to an embodiment of the present invention. FIG. 7 is a diagram showing a waveform of each part of the power supply device 21A, (a) is an output waveform from the AC power supply 22, (b) is a zero-cross point detection timing, (c)
Is a control angle signal 35 output from the control angle setting unit 29,
(D) is a command signal 36 output from the output command unit 30,
(E) is the trigger signal 37 output from the trigger circuit 32, (f) is the on / off state of the triac 25,
(G) is a diagram showing a waveform of the load current 38 flowing through the load 24.

In this power supply device 21A, the power of the AC power supply 22 is supplied to the load 24 via the power control device 23a.
The electric power supplied to the load 24 and to the load 24 is controlled by the electric power control device 23a. This power control device 23a is an AC full-wave control system using a triac 25, and is composed of a zero-cross point detection circuit 26, a phase angle control unit 27, and an output value setting means 28. Further, the phase angle control unit 27 is functionally equivalent to the control angle setting unit 29,
Output command unit 30, counter 31, and trigger circuit 3
It is composed of two. The control angle setting unit 29, the output command unit 30, the counter 31, and the trigger circuit 32 that form the phase angle control unit 27 are realized by software using one or more microcomputers (CPU) or the like. Alternatively, each may be configured by an electric circuit. The same applies to the zero-cross point detection circuit 26 and the output value setting means 28 (the same applies to each of the following embodiments).

The triac 25 is connected in series with the AC power supply 22 and the load 24. The AC power supply 22, the triac 25 and the load 24 form a load circuit, and the load circuit is opened and closed by turning the triac 25 off and on. To do.

The zero-cross point detection circuit 26 is an AC power source 22.
7A, the zero cross point of the AC power supply output 33 (AC power supply voltage) having a waveform as shown in FIG. 7A is detected, and as shown in FIG. The zero-cross point detection signal 34 is output in synchronization. As the zero-cross point detection circuit 26, for example, the zero-cross detection circuit 26 of the method described in the conventional example can be used. The zero-cross point detection signal 34 is output to the control angle setting unit 29 and the output command unit 30.

As shown in FIG. 7C, the control angle setting section 29 outputs a control angle signal 35 at a constant control angle (time) θ ₁ from the zero cross point detection signal 34. Control angle setting unit 2
9 is the pulse generation circuit 7 as described in the conventional example.
May be used, or a timer for measuring the control angle (time) may be used. Further, by using a charge / discharge circuit consisting of a resistor and a capacitor, the control angle signal 35 is output when the capacitor completely discharged at the zero cross point is charged to a constant voltage, and the control constant is changed by changing the time constant CR. It is also possible to adjust θ ₁ . The control angle θ ₁ in the control angle setting unit 29 is set by the output value setting means 28.

The output command unit 30 sets the count value n of the counter 31 to 1 each time it receives the zero-cross point detection signal 34.
When the count value n of the counter 31 becomes equal to the predetermined value N (n = N), the command signal (enable signal) 3 having a half cycle width (phase π) is generated as shown in FIG. 7D.
6 to the trigger circuit 32 and the counter 31
The count value n of is cleared to zero.

When the trigger circuit 32 receives the control angle signal 35 from the control angle setting unit 29 while receiving the command signal 36 from the output command unit 30, it outputs the trigger signal 37 (FIG. 7 (e)). ). As a result, the trigger signal 37 is output once every N times of the zero-cross point detection signal 34, and the cycle of the trigger signal 37 is N times the cycle of the zero-cross point.
Double. When the trigger signal 37 is output, the triac 25 is turned on, is kept conductive until the next zero cross point, and power is supplied to the load 24 (FIG. 7 (f)).
(G)).

FIG. 8 is a flow chart for explaining the operation of the phase angle controller 27 as described above. The count value n of the counter 31 is initially set to n = 0 (S
41). When the zero-cross point is detected and the zero-cross point detection signal 34 is received from the zero-cross point detection circuit 26 (S
42), the control angle setting unit 29 starts measuring the phase angle from the zero cross point (S43) and increments the count value of the counter 31 by 1 (S44). Then, it is determined whether the count value n is equal to the predetermined value N (S4
5). If the count value n of the counter 31 is not equal to the predetermined value N, it does not output the trigger signal 37 and waits until the next zero-cross point is detected (S42). When it is determined in step 45 that the count value n is equal to the predetermined value N, the count value n of the counter 31 is
Is cleared to zero (S46), the control angle setting unit 29 waits until the phase angle being measured becomes equal to the control angle θ ₁ (S47), and when the phase angle becomes equal to the control angle θ ₁ , the trigger circuit 32. To Triac 25 to trigger signal 37
Is output (S48).

The output power from the output value setting means 28
(Or output voltage or output current) desired value A
out (eg RMS, peak, average) can be entered
The control angle in the control angle setting unit 29
θ₁And the value of N in the output command unit 30 is the output value setting
It is calculated by means 28. The output value setting means 28 is shown in FIG.
The processing procedure in will be described. The output value setting means 28
When the desired value Aout of the input output power is read
(S51), with reference value As of the output power stored in advance
The desired value Aout is compared (S52). Based on the desired value Aout
If it is larger than the quasi value As (Aout ≧ As), the output finger
When the value used in the command unit 30 is set to N = 1 (S53),
At the same time, the control angle θ for outputting the electric power of the desired value Aout
₁(0 ≦ θ₁≦ π) is calculated (S54). Calculated N
The value of (= 1) is transmitted to the output command unit 30 (S56),
Control angle θ₁Is transmitted to the control angle setting unit 29 (S5
7). Therefore, in this case, the conventional power control device 3a
As in the case of, the trigger signal 37 detects the zero-cross point.
The signal is output to the triac 25 at the same cycle as the signal 34,
The liaac 25 is in the conducting state at the same frequency as the zero cross point.
And the non-conduction angle α is the control angle θ Equal to 1 and 0 ≤ α ≤ π
Become.

On the other hand, when the desired value Aout is smaller than the reference value As (Aout <As), the output value setting means 28
Is the value of N (≧ 2) used in the output command unit 30 and the control angle θ.
_{The value of 1} (0 ≦ θ ₁ ≦ π) is determined (S55). For example,
The control angle θ ₁ is set to a fixed default value, the value of N (≧ 2) used in the output command unit 30 is calculated, and if necessary, the fine adjustment amount of the control angle θ ₁ is obtained to obtain the desired value Aout. Δ
Find θ ₁ . Alternatively, the value of N and the control angle θ ₁ may be determined using a calculation table stored in advance in the memory. Thus, the value of N and the control angle theta ₁ is determined, the value of N is transmitted to the output instruction section 30 (S56), the value of the control angle theta ₁ is transmitted to the control angle setting unit 29 (S5
7). Therefore, in this case, the conventional power control device 23
Unlike a, the trigger signal 37 is output to the triac 25 at a cycle N times larger than that of the zero-cross point detection signal 34, the triac 25 becomes conductive at a frequency (1 / N) smaller than the zero-cross point, and the non-conduction angle α is Control angle θ ₁
And α = (N−1) π + θ ₁ [therefore, (N−1) π ≦ α ≦ Nπ].

Therefore, in the case of the conventional power control device 3a, it is necessary to reduce the conduction angle θ ₂ of the triac 25 at the time of minute output as shown in FIG. 10 (a), but the power control device according to the present invention is used. In the case of 23a, the conduction angle θ ₂ is not made so small even in the case of a minute output, and FIG.
As shown in (b) [in the case of N = 3] and FIG. 10 (c) [in the case of N = 5], the number of times the triac 25 is turned on is reduced (or the non-conduction angle α is increased). The output power can be controlled to obtain a minute output, and the output can be stabilized even in the case of a minute output. Further, in this case, if the value of N is set to an odd number, it is possible to exclude the DC component as shown in FIGS. In this case, the output can be easily detected.

In the above embodiment, the output command section 30 controls the trigger circuit 32, and even if the trigger signal 37 receives the control angle signal 35, the trigger circuit 32 outputs the trigger signal 37 only once every N times. The output command unit 3 does not output (or does not accept the control angle signal 35).
It is easy to change the design of the 0-based control method as appropriate (the same applies to the following embodiments). For example, even if the output command unit 30 controls the control angle setting unit 29 and the control angle setting unit 29 receives the zero-cross point detection signal 34,
The control angle setting unit 29 may output the control angle signal 35 to the trigger circuit 32 only once every N times (or do not accept the zero-cross point detection signal 34). Even if the output command unit 30 controls the zero-cross point detection circuit 26 and the zero-cross point detection circuit 26 detects the zero-cross point, the zero-cross point detection signal 34 is output from the zero-cross point detection circuit 26 only once every N times. Control angle setting unit 29
It is possible not to output to.

(Second Embodiment) FIG. 11 is a circuit diagram (functional block diagram) showing a power supply device 21B according to another embodiment of the present invention. FIG. 12 is a diagram showing a waveform of each part of the power supply device 21B, and FIG.
2 output waveform, FIG. 12B shows a zero-cross point detection signal 3
4, FIG. 12 (c) is a control angle signal 35, FIG. 12 (d) is a command signal 36 of the output command unit 30, FIG. 12 (e) is a trigger signal 37, and FIG. 12 (f) is a conduction (ON) of the SCR 61. And non-conduction (off), FIG. 12 (g) shows the waveform of the load current 38,
It is a figure which respectively shows. In this power supply device 21B, an AC half-wave control type power control device 23b using an SCR 61 is used. SC of power control device 23b
The components other than the R61 operate in the same manner as the power control device 23a in FIG. 6, but due to the rectification characteristics of the SCR61, the SC
Since the R61 turns on only when the AC power supply output 33 is in the forward direction of the SCR61, the load current 38 is equal to that shown in FIG.
A half-wave waveform is obtained as shown in (g).

Therefore, also in this case, at the time of minute output,
The output can be reduced by reducing the number of conductions per unit time of the SCR 61 to 1 / N without reducing the conduction angle θ ₂ . In this embodiment, the SCR61
Since the trigger signal 37 is output only in the forward direction of, the value of N is preferably an even number.

(Third Embodiment) FIG. 13 is a circuit diagram (functional block diagram) showing a power supply device 21C according to still another embodiment of the present invention, and FIG. 14 shows waveforms of respective parts of the power supply device 21C. It is a figure. In this power supply device 21C, two SCRs 61a, 61 connected in antiparallel are provided.
The power control device 23c of the AC full-wave control system is configured by using b. Alternatively, it can be said that two AC half-wave control power control devices using the SCRs 61a and 61b are combined.

Then, the zero-cross point detection circuit 26 is
When the zero cross point of the AC power supply output 33 as shown in FIG. 14A is detected and the zero cross point detection signal 34 is output (FIG. 14B), the control is performed after the predetermined control angle θ ₁ from the zero cross point detection signal 34. A control angle signal 35 is output from the angle setting unit 29. On the other hand, the counter 31 counts zero-cross points, and the output command unit 30 outputs command signals 36a and 36b each time the zero-cross points are counted N times. However, in this output command unit 30, one of the SCR6
Command signal 36a (FIG. 14) that enables output of trigger signal 37a (FIG. 14 (e)) for turning on 1a.
(D)) and the command signal 36b (FIG. 14 (g)) enabling the output of the trigger signal 37b (FIG. 14 (h)) for turning on the other SCR 61b are alternately output. Therefore, the trigger signal 37a and the trigger signal 37b
Are alternately output every time the zero-cross point detection signal 34 is output N times (FIGS. 14 (e) and 14 (h)).
The two SCRs 61a and 61b are alternately turned on (see FIG.
4 (f) (i)) and an AC full-wave control waveform as shown in FIG. 14 (j) are obtained.

(Fourth Embodiment) FIG. 15 is a circuit diagram (functional block diagram) showing a power supply device 21D according to still another embodiment of the present invention, and FIG. 16 shows waveforms of respective parts of the power supply device 21D. It is a figure. In this power supply device 21D, the SCR 61 and the diode 6 connected in anti-parallel are connected.
2 is used to configure an AC half-wave control type power control device 23d including a combination of a control half-wave and a non-control half-wave.

In this power control device 23d, however, in the case of the forward voltage of the SCR 61, AC half-wave control is performed as in the case of the power control device 23b of FIG. 11, but in the reverse direction of the SCR 61. In case of voltage, diode 6
The load current 38 flows through the entire half cycle through 2. Therefore, the waveform of the load current 38 is as shown in FIG.

In such a power control system, the output power cannot be made smaller than 1/2 of the power supply power, and in the conventional power control device 3b of the system, the output power is 1/2 of the power supply power. When approaching, the conduction angle θ ₂ in the forward direction becomes very small and the output becomes unstable. On the other hand, according to the present invention, the output power can be brought close to ½ of the power supply power without reducing the conduction angle θ ₂ in the forward direction, and the output does not become unstable.

[0055]

According to the power control device of the phase angle control system of claim 1, 2, 3, 4, 6 or 7, and the power supply device of claim 8, very small output power is required. At the time of minute output, the output power can be reduced without reducing the conduction angle of the thyristor, so that the output power can be stabilized without being unstable due to noise or the like. Further, since it is not necessary to reduce the conduction angle, it is possible to prevent the conduction angle from becoming close to the turn-on time and the turn-off time of the thyristor, and the control accuracy of the output power is reduced.

Further, since the conduction angle can be maintained to some extent even at the minute output, the variation of the conduction angle can be reduced even when the control angle and the conduction angle are time-controlled and the frequency of the AC power source fluctuates. Yes, the output can be stabilized.

Further, in the power control apparatus of the AC full-wave control system according to the fifth aspect, the thyristors can be alternately turned on with the positive and negative polarities of the AC power supply output, and the AC power containing no DC component is output. can do. Therefore, the output can be easily detected.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a conventional AC full-wave control type power supply device.

2A, 2B, and 2C are waveform charts for explaining an example of a zero-cross point detection method by the above-described zero-cross point detection circuit.

3 (a) to 3 (f) are diagrams for explaining the operation of the above power control device, FIG. 3 (a) is an output waveform diagram from an AC power supply, and FIG. 3 (b) is a zero-cross point detection timing. Figure,
(C) is a waveform diagram showing a pulse signal output from the pulse generation circuit, (d) is a trigger signal output from the trigger circuit, (e) is a diagram showing the on / off state of the triac, (f) is a load It is a figure which shows the electric current waveform which flows into. Further, (g) is a diagram showing a waveform of a current flowing through the load when the control angle is small.

FIG. 4 is a circuit diagram showing a conventional AC half-wave control type power supply device.

5 (a) to 5 (f) are diagrams for explaining the operation of the above power control device, FIG. 5 (a) is an output waveform diagram from an AC power supply, and FIG. 5 (b) is a detection timing of a zero-cross point. Figure,
(C) is a waveform diagram showing a pulse signal output from the pulse generation circuit, (d) is a trigger signal output from the trigger circuit, (e) is a diagram showing the on / off state of the SCR,
(F) is a figure which shows the current waveform which flows into a load.

FIG. 6 is a circuit diagram (functional block diagram) showing an AC full-wave control type power supply device according to the present invention.

7 (a) to (g) are diagrams showing waveforms of respective portions of the power supply device of the above, FIG. 7 (a) is an output waveform diagram from an AC power supply, and FIG. 7 (b) is a detection timing of a zero-cross point. The figure which shows, (c) the figure which shows the control angle signal which is output from the control angle setting section, (d) the figure which shows the command signal which is output from the output command section, (e) the trigger which is output from the trigger circuit FIG. 6 is a diagram showing signals, (f) is a diagram showing ON / OFF states of the triac, and (g) is a diagram showing current waveforms flowing in the load.

FIG. 8 is a flowchart showing a processing procedure of the above power control device.

FIG. 9 is a flowchart showing a processing procedure of the output value setting means of the above.

10A is a diagram showing an output waveform at the time of minute output by the conventional power supply device, and FIG. 10B is a diagram showing an output waveform at the time of minute output by the power supply device of the present invention.

FIG. 11 is a circuit diagram (functional block diagram) showing an AC half-wave control type power supply device according to the present invention.

12 (a) to (g) are diagrams showing waveforms of respective parts of the power supply device of the above, FIG. 12 (a) is an output waveform diagram from an AC power source, and FIG. 12 (b) is a detection timing of a zero-cross point. The figure which shows, (c) the figure which shows the control angle signal which is output from the control angle setting section, (d) the figure which shows the command signal which is output from the output command section, (e) the trigger which is output from the trigger circuit FIG. 6 is a diagram showing signals, (f) is a diagram showing ON / OFF states of the SCR, and (g) is a diagram showing waveforms of currents flowing in a load.

FIG. 13 is a circuit diagram (functional block diagram) showing still another power supply device according to the present invention.

14 (a) to (j) are diagrams showing waveforms of respective parts of the power supply device of the above, FIG. 14 (a) is a waveform diagram of output from an AC power source, and FIG. 14 (b) is a detection timing of a zero-cross point. Drawing (c) is a figure showing a control angle signal outputted from a control angle setting part, (d) is a figure showing one command signal outputted from an output command part, (e) is one SCR from a trigger circuit
Showing the trigger signal output to the
The figure which shows the on / off state of CR, (g) the figure which shows the other command signal output from an output command part, (h) the figure which shows the trigger signal output from a trigger circuit to the other SCR, ( (i) is a diagram showing an on / off state of the other SCR, and (j) is a diagram showing a waveform of a current flowing through a load.

FIG. 15 is a circuit diagram (functional block diagram) showing still another power supply device according to the present invention.

16 (a) to 16 (g) are diagrams showing waveforms of respective parts of the power supply device of the above, FIG. 16 (a) is an output waveform diagram from an AC power supply, and FIG. 16 (b) is a detection timing of a zero-cross point. The figure which shows, (c) the figure which shows the control angle signal which is output from the control angle setting section, (d) the figure which shows the command signal which is output from the output command section, (e) the trigger which is output from the trigger circuit FIG. 6 is a diagram showing signals, (f) is a diagram showing ON / OFF states of the SCR, and (g) is a diagram showing waveforms of currents flowing in a load.

[Explanation of symbols]

 22 AC power supply 23a to 23d Power control device 24 Load 25 Triac 26 Zero cross point detection circuit 27 Phase angle control unit 28 Output value setting means 29 Control angle setting unit 30 Output command unit 32 Trigger circuit 34 Zero cross point detection signal 35 Control angle signal 36 Command signal 37 Trigger signal 61 SCR

Claims (8)

[Claims] 1. A thyristor for connecting to an AC power source and a load to form a load circuit, a zero-cross point detecting means for detecting a zero-cross point of an AC power output, and a zero-cross point detected by the zero-cross point detecting means. From a predetermined control angle, a phase angle control means for outputting a trigger signal for conducting the thyristor, in the power control device, the phase angle control means, the trigger signal of the cycle of the zero cross point A power control device that can output at multiple times. 2. When the output power, the output voltage or the output current is equal to or more than a predetermined value, the trigger signal is output at the same cycle as the zero-cross point, and when the output power, the output voltage or the output current is equal to or less than the predetermined value. The power control device according to claim 1, wherein the power control device outputs the trigger signal in a cycle that is a multiple of the cycle of the zero-cross point. 3. A thyristor for connecting to an AC power source and a load to form a load circuit, a zero-cross point detecting means for detecting a zero-cross point of the AC power output, and a zero-cross point detected by the zero-cross point detecting means. And a phase angle control means for keeping the thyristor in a non-conducting state in a section of a predetermined non-conduction angle and conducting the thyristor at the end of the section of the non-conduction angle; In the device, the phase angle control means is capable of setting the non-conduction angle to a phase angle larger than π radians. 4. A thyristor for connecting to an AC power source and a load to form a load circuit, a zero-cross point detecting means for detecting a zero-cross point of the AC power output, and a zero-cross point detected by the zero-cross point detecting means. And a phase angle control unit that conducts the thyristor at a predetermined control angle from the AC full-wave control system, the phase angle control unit has a zero cross point of an AC power supply output that is equal to or greater than a predetermined value. A power control device capable of conducting the thyristor every time the number of times is detected. 5. The power control device according to claim 4, wherein the number of times of detecting the zero-cross point for conducting the thyristor is an odd number. 6. A thyristor for forming a load circuit by connecting to an AC power source and a load, a zero-cross point detecting means for detecting a zero-cross point of an AC power output, and a zero-cross point detected by the zero-cross point detecting means. AC half-wave control method power control, comprising: a phase angle control means for keeping the thyristor in a non-conducting state in a section of a predetermined non-conduction angle based on In the device, the phase angle control means is capable of setting the non-conduction angle to a phase angle larger than 2π radians. 7. A thyristor for connecting to an AC power source and a load to form a load circuit, a zero-cross point detecting means for detecting a zero-cross point of an AC power source output, and a zero-cross point detected by the zero-cross point detecting means. And a phase angle control unit that conducts the thyristor at a predetermined control angle from the AC half-wave control system, the phase angle control unit has a predetermined zero-cross point of AC power output of three or more times. A power control device capable of conducting the thyristor every time the number of times is detected. 8. An alternating current power supply, and claim 1, 2, 3, 4,
5. A power supply device comprising the power control device according to 5, 6, or 7, wherein the power control device controls an output value of power, voltage, or current supplied from an AC power supply.