JP2739298B2 - Power control device and power supply device - Google Patents

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 control the phase angle of output power or output voltage or output current of an AC power supply using a thyristor.

[0002]

2. Description of the Related Art Electric power for controlling electric power (power consumption) or voltage (load voltage) or current (load current) (hereinafter, simply referred to as electric power) to be output to a heat-generating portion such as a heater, an electric heater or other load. In a control device and a power supply device, the output of an AC power supply is controlled by controlling the phase angle 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) FIG. 1 shows an example of such a power supply device (power supply device) 1A. In the 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. The power control device 3a is an AC full-wave control system using a triac 5, and includes a zero-cross point detection circuit 6, a pulse generation circuit 7, a trigger circuit 8, and a triac 5.

[0004] The triac 5 includes an AC power supply 2 and a load 4.
Are connected in series with AC power supply 2 and triac 5
A load circuit is configured by the load 4 and the triac 5 is turned off and on so that the load circuit can be opened and closed.

A zero cross point detection circuit 6 is connected to one output of the AC power supply 2 and detects a zero cross point of an AC power supply output (AC power supply voltage). That is, FIG.
FIG. 2 is a waveform diagram showing the AC power supply output 9. A zero-cross point detection circuit 6 detects the AC power supply output 9 and performs full-wave rectification on the AC power supply output 9 to obtain a full-wave rectified waveform as shown in FIG. 1
Get 0. Then, the full-wave rectified waveform 10 is compared with a predetermined threshold value Vth, and a zero-cross 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-crossing point detection method in the zero-crossing point detection circuit 6 is based on the fact that the original AC power
It may be compared with two threshold values Vth and -Vth.

In this manner, as shown in FIGS. 3A and 3B, the zero cross point of the AC power supply output 9 is detected by the zero cross point detection circuit 6, and the zero cross point detection signal 12 (the zero cross detection pulse 11) is supplied to the pulse generation circuit 7. Is output, the pulse generating circuit 7 outputs the signal 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. 3D). . When the trigger signal 14 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
Becomes zero 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. 3E, and the waveform of the load current 15 (in the case of a resistive load) is as shown in FIG.

In the case of phase angle control, changes in thyristor operation, load current, and the like are usually expressed by the phase angle of the output of the AC power supply, so that the control angle (trigger phase angle) θ ₁ used below is used. , A non-conduction angle α and a conduction angle θ ₂ (see FIGS. 3F and 5F). Control angle θ
₁ is the phase angle from the moment when the thyristor is turned on to the immediately preceding zero-cross point. AC power output 1
Since the cycle is 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 theta 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 turned on thyristor turns off at the next zero crossing point, the turning angle θ ₂ is 0 ≦ θ ₂ ≦ π. In addition, 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 where the thyristor is continuously in a non-conduction state.

If the AC full-wave control method shown in FIG. 3 is described again using the phase, the zero-cross point is detected at a period of every phase π (FIG. 3B), and the trigger signal 14 is generated from each zero-cross point. Is output for each phase π with a delay of the control angle θ ₁ (FIG. 3D). Accordingly, the triac 5 is turned on every time with a delay of the control angle θ ₁ from the zero cross point,
The load current 15 is supplied to the load circuit, turned off at the next zero-cross point, and the load current 15 is cut off (FIG. 3E).
(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 apparatus has the following features or restrictions. A trigger signal is output every time a zero-cross point is detected, and the period of the trigger signal is equal to the period (π) of the zero-cross point. 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 a zero-cross point is detected. Therefore, the power to be output (e.g., effective value, peak value, average value) is extremely small micro On output, FIG conduction angle control angle theta ₁ close to π as shown in (g) theta ₂ Had to be very small.

(Conventional AC Half-Wave Control System) Next, a 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
R16 is connected, and the load circuit is opened and closed by SCR16.

Also in the current control device 3b, the zero cross point of the AC power supply output 9 in FIG. 5A is detected by the zero cross point detection circuit 6, and the zero cross point detection signal 12 is output for each phase π ( FIG. 5 (b)). 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. 8, a trigger signal 14 is output at a period of every phase π (FIG. 5D). Therefore, FIG.
(E) As shown in (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 through 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. Also, in the case of the reverse voltage, even if the trigger signal 14 is output from the trigger circuit 8, the SCR 16 is not turned 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 system, the trigger signal 14 is output at the same cycle as the zero-cross point, but the triac is turned on at twice the 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 apparatus has the following features or restrictions. A trigger signal is output every time a zero-cross point is detected, and the period of the trigger signal is equal to the period (π) of the zero-cross point. The non-conduction angle α is the 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. However, when the power to be output (for example, the effective value, the peak value, and the average value) is extremely small, the thyristor still needs the AC full-wave control method. Similarly, the conduction angle θ _{2 has} to be made very small by making the control angle θ ₁ close to π.

[0013]

As described above, in the power control device of the phase angle control system, an extremely small output power is required regardless of the case of the AC full-wave control or the case of the AC half-wave control. during that minute output, it is necessary to very small conduction angle theta ₂ of the thyristor. For this reason, there has been a problem that the instantaneous value and peak value of the output power become small, and the output becomes unstable due to noise or the like. Moreover, approaches the turn-on time and turn-off time of the thyristor becomes smaller conduction angle theta _2, the control accuracy of the output power is lowered.

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

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described drawbacks of the prior art, and has as its object to reduce the conduction angle of a thyristor in a phase control type power control device or power supply device. Instead, it is possible to reduce output power, output voltage, and output current, and to improve output stability at the time of minute output.

[0016]

A power control device according to a first aspect of the present invention includes a thyristor for connecting to an AC power supply and a load to form a load circuit, and a zero-cross point detecting means for detecting a zero-cross point of the AC power output. 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, and a phase angle control means, , Wherein the trigger signal can be output at 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), a triac (TRIAC; bidirectional three-terminal thyristor) or another thyristor element.

When the power control device is connected to an AC power supply, the zero cross point detecting means detects a zero cross point of the output of the AC power supply, and the phase angle control means triggers at a predetermined control angle from the zero cross points detected at intervals. A signal is output, and when a trigger signal is output, the thyristor of the load circuit is turned on and becomes conductive until the next zero crossing point, and outputs power to the load. Thus, power is supplied to the load at a constant conduction angle, and power output to the load can be controlled by changing the control angle.

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

Here, in the power control apparatus according to the first aspect, 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,
When the output power, output voltage, or output current is equal to or less than a predetermined value, the trigger signal is output at 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 equal to or smaller than the predetermined value, the output power can be reduced without increasing the conduction angle of the thyristor by increasing the period of the trigger signal. can do. When the output power is larger than the predetermined value, the output power can be increased while the conduction cycle of the thyristor is kept constant.

According to a third aspect of the present invention, there is provided a power control apparatus comprising: a thyristor for connecting to an AC power supply and a load to form a load circuit; zero-cross point detection means for detecting a zero-cross point of the AC power output; Phase angle control means for keeping the thyristor in a non-conductive state in a section of a predetermined non-conductive angle with reference to the zero cross point detected by the point detecting means, and conducting the thyristor at the end of the section of the non-conductive angle. In the power control apparatus of the AC full-wave control system, the phase angle control means can set the non-conduction angle to a phase angle larger than π radian.

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

In this power control device, in the AC full-wave control system, the non-conduction angle can be set to a phase angle larger than π radian, so that the conduction angle can be reduced to reduce the output power. Instead, the output power can be reduced by increasing the non-conduction angle while maintaining the conduction angle at an appropriate value.

The power control device according to claim 4 is
A thyristor for connecting to an AC power supply and a load to form a load circuit; zero-cross point detection 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 detection means. And a phase angle control means for conducting the thyristor in the AC full-wave control type power control apparatus, wherein the phase angle control means detects the zero cross point of the AC power supply output two or more predetermined times. In addition, the thyristor can be made conductive.

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

Furthermore, an embodiment according to a fifth aspect is characterized in that, in the power control device according to the fourth aspect, the number of times of detection of 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 every odd number of times at the zero-cross point, so that the thyristor is turned on alternately with the positive and negative polarities of the AC power supply output. I do. Therefore, according to this power control device, an output containing no DC component can be obtained.

According to a sixth aspect of the present invention, there is provided a power control apparatus comprising: a thyristor for connecting to an AC power supply and a load to form a load circuit; zero-cross point detection means for detecting a zero-cross point of the AC power output; Phase angle control means for keeping the thyristor in a non-conductive state in a section of a predetermined non-conductive angle with reference to the zero cross point detected by the point detecting means, and conducting the thyristor at the end of the section of the non-conductive angle. In the AC power control apparatus of the half-wave control system, the phase angle control means can set the non-conduction angle to a phase angle larger than 2π radian.

Here, the AC half-wave control system controls the trigger phase angle in only one polarity.
There are cases where only the control half wave is used, and cases where the control half wave and the non-control half wave are combined.

In this power control apparatus, in the AC half-wave control system, the non-conduction angle can be set to a phase angle larger than 2π radian, so that the conduction angle can be reduced to reduce the output power. Instead, the output power can be reduced by increasing the non-conduction angle while maintaining the conduction angle at an appropriate value.

The power control device according to claim 7 is
A thyristor for connecting to an AC power supply and a load to form a load circuit; zero-cross point detection 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 detection means. And a phase angle control means for conducting the thyristor in the AC half-wave control method, wherein the phase angle control means detects a zero-cross point of the AC power output three or more predetermined times. In addition, the thyristor can be made conductive.

In this power control device, in the AC half-wave control system, the thyristor is turned on each time the zero-cross point of the AC power supply output is detected two or more predetermined times. Compared with the power control device of the wave control system, the number of conductions of the thyristor is thinned out, the number of conductions 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 the present invention includes an AC power supply and the power control device, and controls the output value of the power or the voltage or the current supplied from the AC power supply by the power control device. It is characterized by doing.

Therefore, in this power supply device, at the time of minute 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 one embodiment of the present invention. 7A and 7B are diagrams showing waveforms of respective parts of the power supply device 21A, wherein FIG. 7A shows an output waveform from the AC power supply 22, FIG. 7B shows a detection timing of a zero-cross point, and FIG.
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 a load current 38 flowing through the load 24.

In the power supply device 21A, the power of the AC power supply 22 is supplied to the load 24 via the power control device 23a.
And the power supplied to the load 24 is controlled by the power controller 23a. The power control device 23a is an AC full-wave control system using a triac 25, and includes a zero-cross point detection circuit 26, a phase angle control unit 27, and output value setting means 28. In addition, the phase angle control unit 27 includes a control angle setting unit 29,
Output command unit 30, counter 31, and trigger circuit 3
2. The control angle setting unit 29, the output command unit 30, the counter 31, and the trigger circuit 32 constituting the phase angle control unit 27 are realized by software using one or more microcomputers (CPU) or the like. Or each may be constituted by an electric circuit. The same applies to the zero-crossing point detection circuit 26 and the output value setting means 28 (the same applies to the following embodiments).

The triac 25 is connected in series with the AC power supply 22 and the load 24, and forms a load circuit with the AC power supply 22, the triac 25 and the load 24, and turns the triac 25 off and on to open and close the load circuit. I do.

The zero-cross point detection circuit 26 is connected to the AC power supply 22
7A, a 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-crossing point detection signal 34 is output in synchronization. As the zero-cross point detection circuit 26, for example, a zero-cross detection circuit 26 of the type described in the conventional example can be used. This zero-crossing point detection signal 34 is output to the control angle setting unit 29 and the output command unit 30.

The control angle setting unit 29 outputs a control angle signal 35 at a constant control angle (time) θ ₁ from the zero cross point detection signal 34 as shown in FIG. 7C. Control angle setting unit 2
9 is a 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. In addition, a charge / discharge circuit including a resistor and a capacitor is used to output a control angle signal 35 when the capacitor completely discharged at the zero cross point is charged to a constant voltage, and the control angle is changed by changing the time constant CR. θ ₁ may be adjusted. The control angle θ ₁ in the control angle setting section 29 is set by the output value setting means 28.

The output command section 30 sets the count value n of the counter 31 to 1 each time the zero cross point detection signal 34 is received.
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) 3 as shown in FIG.
6 to the trigger circuit 32 and the counter 31
Is cleared to zero.

When the trigger circuit 32 receives the control angle signal 35 from the control angle setting section 29 while receiving the command signal 36 from the output command section 30, it outputs a 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 in a conductive state until the next zero-cross point, and power is supplied to the load 24 (FIG. 7 (f)).
(G)).

FIG. 8 is a flowchart for explaining the operation of the phase angle control unit 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 increases the count value of the counter 31 by 1 (S44). Next, 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, the process waits until the next zero-cross point is detected without outputting the trigger signal 37 (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 determined.
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 Trigger signal 37 to TRIAC 25
Is output (S48).

The output value setting means 28 outputs the output power
(Or desired value A of output voltage or output current)
out (eg rms, peak, average)
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.
The calculation is performed by the means 28. FIG. 9 shows the output value setting means 28.
Will be described. The output value setting means 28
When the desired value Aout of the input output power is read,
(S51), a reference value As of the output power stored in advance and
A comparison is made with the desired value Aout (S52). Based on desired value Aout
If it is larger than the quasi-value As (Aout ≧ As), the output finger
When the value used in the command section 30 is set to N = 1 (S53)
In addition, the control angle θ for outputting the power of the desired value Aout
₁(0 ≦ θ₁≦ π) (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 is detected as a zero-cross point.
The signal is output to the triac 25 at the same cycle as the signal 34,
Liac 25 becomes conductive 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, if 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 predetermined value, and the value of N (≧ 2) used in the output command unit 30 is calculated. If necessary, a small adjustment amount of the control angle θ ₁ is obtained to obtain a desired value Aout. Δ
seek θ _1. Alternatively, the value of N and the control angle θ ₁ may be determined using an operation table stored in the memory in advance. 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 the 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, and the triac 25 becomes conductive at a frequency (1 / N) smaller than the zero-cross point, and the non-conductive angle α becomes Control angle θ ₁
Α = (N−1) π + θ ₁ [Accordingly, (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 as shown in FIG. in the case of 23a, even when the minute output, without too small conduction angle theta _2, FIG. 10
(B) As shown in [when N = 3] and FIG. 10 (c) [when N = 5], by reducing the number of turn-on of the triac 25 (or increasing the non-conduction angle α), A small output can be obtained by controlling the output power, and the output can be stabilized even in the case of a small output. In this case, if the value of N is set to an odd number, the DC component can be excluded as shown in FIGS. 10B and 10C, and the load 24 requiring AC power can be eliminated. And 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. Although the output is not made (or the control angle signal 35 is not accepted), the output command unit 3
It is easy to appropriately change the design of the control method using 0 (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 may not receive the zero cross point detection signal 34). Further, even when 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 can also be prevented from being 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 waveforms at various parts of the power supply device 21B, and FIG.
12 (b) shows the zero-cross point detection signal 3
4, FIG. 12 (c) is the control angle signal 35, FIG. 12 (d) is the command signal 36 of the output command unit 30, FIG. 12 (e) is the trigger signal 37, and FIG. 12 (f) is the conduction (ON) of the SCR 61. 12 (g) shows the waveform of the load current 38,
FIG. In the power supply device 21B, a power control device 23b of an AC half-wave control system using the SCR 61 is used. SC of power control device 23b
The components other than R61 operate in the same manner as the power control device 23a of FIG.
R61 turns on only when the AC power output 33 is in the forward direction of the SCR 61.
It has a half-wave waveform as shown in FIG.

Therefore, also in this case, at the time of minute output,
Without reducing the conduction angle theta _2, it is possible to reduce the output by the conduction number per unit time of SCR61 to 1 / N. In this embodiment, the SCR 61
In order to output the trigger signal 37 only in the forward direction, 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 at various parts of the power supply device 21C. FIG. In this power supply device 21C, two SCRs 61a, 61 connected in anti-parallel are provided.
The power control device 23c of the AC full-wave control system is configured using b. Alternatively, it can be said that two AC half-wave control power control devices using the SCRs 61a and 61b are combined.

Thus, the zero-cross point detection circuit 26
When a zero-cross point of the AC power supply output 33 as shown in FIG. 14A is detected and a zero-cross point detection signal 34 is output (FIG. 14B), control is performed after a 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 every time the zero-cross points are counted N times. However, in this output command unit 30, one SCR6
A command signal 36a (FIG. 14) for enabling the output of a trigger signal 37a (FIG. 14 (e)) for turning on the
(D)) and a command signal 36b (FIG. 14 (g)) enabling output of a 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 output alternately each time the zero-crossing point detection signal 34 is output N times (FIGS. 14 (e) and 14 (h)).
The two SCRs 61a and 61b are turned on alternately (FIG. 1).
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 at various parts of the power supply device 21D. FIG. In the power supply device 21D, the SCR 61 and the diode 6 connected in anti-parallel are connected.
2 is used to constitute an AC half-wave control type power control device 23d composed of a combination of a control half-wave and a non-control half-wave.

In the power control device 23d, in the case of the forward voltage of the SCR 61, the AC half-wave control is performed as in the case of the power control device 23b of FIG. In the case of voltage, diode 6
2, the load current 38 flows in the entire half cycle. 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 電源 of the power supply power. In the conventional power control device 3b of the system, the output power is reduced to １ ／ 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 made close to 電源 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 method 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 the output power becoming unstable due to noise or the like. Furthermore, since it is not necessary to reduce the conduction angle, it is possible to prevent the conduction angle from approaching the thyristor's turn-on time or turn-off time, thereby reducing the control accuracy of the output power.

Further, since the conduction angle can be maintained to some extent even at the time of minute output, the control angle and the conduction angle are controlled over time, and even when the frequency of the AC power supply fluctuates, the fluctuation of the conduction angle can be reduced. Output can be stabilized.

In the power control apparatus of the AC full-wave control system according to the present invention, the thyristor can be turned on alternately with the positive and negative polarities of the output of the AC power supply, and the AC power containing no DC component is output. can do. Therefore, the output can be easily detected.

[Brief description of the drawings]

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

FIGS. 2A, 2B, and 2C are waveform diagrams illustrating an example of a zero-cross point detection method using 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) shows 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 triac, and (f) is a load. FIG. 3 is a diagram showing a waveform of a current flowing through the circuit. (G) is a diagram showing a waveform of a current flowing to 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) shows 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 diagram showing a waveform of a current flowing through 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 7 (g) are diagrams showing waveforms of respective parts of the above power supply device, wherein FIG. 7 (a) is an output waveform diagram from an AC power supply, and FIG. 7 (b) is a timing chart for detecting a zero-cross point. (C) is a diagram showing a control angle signal output from a control angle setting unit, (d) is a diagram showing a command signal output from an output command unit, and (e) is a trigger output from a trigger circuit. FIG. 7F is a diagram showing signals, FIG. 7F is a diagram showing the on / off state of the triac, and FIG. 7G is a diagram showing a waveform of a current flowing to 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 an output value setting unit according to the embodiment.

10A is a diagram showing an output waveform at a minute output by a conventional power supply device, and FIGS. 10B and 10C are diagrams showing an output waveform at a 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 12 (g) are diagrams showing waveforms of respective parts of the above power supply device, where FIG. 12 (a) is an output waveform diagram from an AC power supply, and FIG. 12 (b) is a timing chart for detecting a zero-cross point. (C) is a diagram showing a control angle signal output from a control angle setting unit, (d) is a diagram showing a command signal output from an output command unit, and (e) is a trigger output from a trigger circuit. FIG. 7F is a diagram showing signals, FIG. 7F is a diagram showing the ON / OFF state of the SCR, and FIG. 7G is a diagram showing a waveform of a current flowing to 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 the respective parts of the power supply device according to the first embodiment, (a) is an output waveform diagram from an AC power supply, and (b) is a detection timing of a zero cross point. FIG. 3C is a diagram illustrating a control angle signal output from the control angle setting unit, FIG. 4D is a diagram illustrating one command signal output from the output command unit, and FIG. 4E is a diagram illustrating one SCR from the trigger circuit.
FIG. 7F shows a trigger signal output to S. FIG.
(G) is a diagram showing the other command signal output from the output command unit, (h) is a diagram showing a trigger signal output from the trigger circuit to the other SCR, (i) is a diagram showing the ON / OFF state of the other SCR, and (j) is a diagram showing a waveform of a current flowing to the load.

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

16 (a) to (g) are diagrams showing waveforms of respective parts of the above power supply device, (a) is an output waveform diagram from an AC power supply, and (b) is a detection timing of a zero cross point. (C) is a diagram showing a control angle signal output from a control angle setting unit, (d) is a diagram showing a command signal output from an output command unit, and (e) is a trigger output from a trigger circuit. FIG. 7F is a diagram showing signals, FIG. 7F is a diagram showing the ON / OFF state of the SCR, and FIG. 7G is a diagram showing a waveform of a current flowing to a load.

[Explanation of symbols]

 Reference Signs List 22 AC power supplies 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)

(57) [Claims] A thyristor for connecting to an AC power supply 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 outputs a trigger signal for turning on the thyristor at a predetermined control angle, wherein the phase angle control unit transmits the trigger signal to the cycle of the zero-cross point. A power control device that can output at multiple times the cycle. 2. When the output power, output voltage, or output current is equal to or greater than a predetermined value, the trigger signal is output in the same cycle as the zero-cross point, and when the output power, output voltage, or output current is equal to or less than a predetermined value. 2. The power control device according to claim 1, wherein the trigger signal is output at a period that is a multiple of a period of a zero crossing point. 3. A thyristor for connecting to an AC power supply and a load to form a load circuit, zero-cross point detection means for detecting a zero-cross point of the AC power output, and a zero-cross point detected by the zero-cross point detection means. A phase angle control unit that keeps the thyristor in a non-conducting state in a section of a predetermined non-conducting angle with respect to the thyristor and conducts the thyristor at an end of the section of the non-conducting angle. In the device, the phase angle control means can set the non-conduction angle to a phase angle larger than π radian. 4. A thyristor for connecting to an AC power supply 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 conducting the thyristor at a predetermined control angle from a power control device of an AC full-wave control method, wherein the phase angle control means has a zero cross point of an AC power supply output of two or more predetermined times. The power control device, wherein the thyristor is made conductive every time the number of times is detected. 5. The power control device according to claim 4, wherein the number of times the zero-cross point is detected for conducting the thyristor is an odd number. 6. A thyristor for configuring a load circuit by connecting to an AC power supply and a load, 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. A phase angle control means for maintaining the thyristor in a non-conducting state in a section of a predetermined non-conducting angle with respect to the thyristor and conducting the thyristor at the end of the section of the non-conducting angle. In the apparatus, the phase angle control means can set the non-conduction angle to a phase angle larger than 2π radian. 7. A thyristor for configuring a load circuit by connecting to an AC power supply and a load, 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 conducting the thyristor at a predetermined control angle from the following. A power control device of an AC half-wave control system, wherein the phase angle control means has a zero cross point of the AC power output three or more times. The power control device, wherein the thyristor is made conductive every time the number of times is detected. 8. An AC power supply, and wherein
A power supply device, comprising: the power control device according to 5, 6, or 7, wherein an output value of power, voltage, or current supplied from an AC power supply is controlled by the power control device.