JPH04281363A - Power supply controller - Google Patents

Abstract

PURPOSE:To provide a power supply controller for power heating element in which same quantity of heat can be produced even if the power heating element is fed with power from any one of a plurality of AC power supplies, e.g. 100V power supply and 200V power supply, and a voltage can be applied smoothly from a zero volt point of AC cycle. CONSTITUTION:The power supply controller comprises a zero-cross detection switch S comprising a photo-triac 3 incorporating a zero-cross detecting circuit and a triac 2 and switching power supply to a power heating element 1 ON, OFF upon detection of zero-cross of power supply voltage, a power supply informing means, i.e., a 100V/200V change-over switch 5, for switching the output in response to switching of power supply voltage, and an oscillation circuit 6 constituting a duty control circuit for varying the duty of ON signal in response to an output from the power supply informing means and outputting thus varied duty, wherein the zero-cross detection switch S is controlled based on the output from the oscillation circuit 6.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply control device capable of supplying power to a load from a plurality of alternating current power supply voltages, such as a 100V power supply or a 240V power supply.

0002

2. Description of the Related Art Conventionally, phase control has been widely used as a power supply control technique that enables loads such as lamps and heaters (hereinafter referred to as power heating elements) to be used at a plurality of power supply voltages.

FIG. 6 shows a block diagram of a power supply control device for a power heating element using phase control. In Fig. 6, 1 is a power heating element that is a load whose resistance value does not change even when the temperature changes, 2 is a triac, 4 is a phototriac, and 5 is a power source that outputs signals of different voltages in conjunction with switching the power source. A 100V/240V selector switch is the notification means. 8 is a trigger output circuit, 9 is a zero cross detection circuit,
E is an AC power supply that supplies power to the power heating element 1, and is 100V.
It consists of a power supply and a 240V power supply.

FIG. 7 is a waveform diagram showing the operation of the conventional example, in which a is a zero-cross signal, b is a trigger signal when power is supplied from a 100V power supply, c is a trigger signal when power is supplied from a 240V power supply, and d is a power supply voltage. In the waveforms, e shows the power supply voltage waveform to the power heating element 1 when the power source is 100V, and f shows the power supply voltage waveform when the power supply is 240V. The operation of the conventional example will be described below with reference to the same waveform diagram.

The power heating element 1 can obtain a desired amount of heat when a power supply voltage of 100V is directly applied thereto, and the changeover switch 5 notifies the trigger output circuit 8 whether the power supply voltage E is 100V or 240V. The trigger output circuit 8 outputs a power supply voltage of 10% in synchronization with the zero-crossing signal a shown in the applied waveform diagram of FIG. 7 outputted from the zero-crossing detection circuit 9.
When the power supply voltage is 0V, a trigger output as shown in FIG. 7b is generated, and when the power supply voltage is 240V, a trigger output as shown in FIG. 7c is generated.

The above trigger output controls the triac 2 via the phototriac 4 and controls the on/off phase of the power supply from the power source E, and the trigger generation timing shown in FIG. 7c is set at the desired timing when 240V is applied. The phase timing at which effective power is obtained, that is, the phase is controlled so that the same amount of heat is obtained as when 100 V is directly applied to the power heating element 1, and the trigger period depends on the frequency of the power source E.

The trigger output is input to the light emitting diode side of the phototriac 4 and transmitted to the triac 2.
Raise the gate potential and turn it on. Therefore, with respect to the power supply voltage d shown in FIG. 7, a voltage such as e in FIG. 7 is applied to the power heating element 1 when it is 100V, and voltage f shown in FIG. 7 when it is 240V is applied to the power heating element 1.

[0008]

However, in the conventional phase control described above, when the power supply voltage E is 240V, the accuracy of the zero-cross detection circuit 8 influences the accuracy of the power supplied to the power heating element 1. Further, when the above control is used for a plurality of power supply frequencies, the control becomes complicated as the generation timing of the trigger waveform c shown in FIG. 7 must be changed according to the frequency. Furthermore, there is a problem in that control becomes even more difficult when the frequency of the power source fluctuates.

Furthermore, as shown in FIG. 7f, the voltage applied to the power heating element is in an inrush state where it changes sharply from zero volts, causing an instantaneous change in the supplied power and increasing power terminal noise. .

[0010] This invention was made to solve the above-mentioned problems of the prior art, and the power heating element can be supplied with the same power even if it is supplied from a plurality of AC power supply voltages, for example, a 100V power supply or a 240V power supply. It is an object of the present invention to provide a power supply control device for a power heating element that can obtain the amount of heat or light and can smoothly apply voltage from the zero volt point of the AC cycle.

[0011]

[Means for Solving the Problems] Therefore, the power supply control device according to the present invention is a power supply control device for a load used with a plurality of power supply voltages, and includes a built-in zero-crossing detection circuit to detect zero-crossing of the power supply voltage. a zero-cross detection switch that turns on and off the power supply to the load when the load is turned on, a power supply notification means that switches the output in response to a change in the power supply voltage, and an on signal whose duty is changed in response to the output of the power supply notification means. The above-mentioned object is achieved by a configuration characterized in that the present invention includes a duty control circuit that outputs a voltage, and inputs the output of the duty control circuit to a zero-cross detection switch to control power supply to a load.

Further, in the above configuration, the duty control circuit has a ratio of a pair of on output time and an off output time adjacent on the output time axis to a ratio of a pair of on output time and off output time output immediately before. The above object is achieved by a configuration characterized in that the outputs are controlled differently.

[0013]

[Operation] With the above configuration, the zero-cross detection switch turns on the power supply to the load (power heating element) when the zero-cross of the power supply voltage is detected by the built-in zero-cross detection circuit.
Switch off. The output switched in response to the change in power supply voltage from the power supply notification means is input to the duty control circuit, and the duty control circuit changes the duty of the ON signal output in response to the input power supply voltage signal and outputs it, and zero-crossing is achieved. The power is controlled so that the power heating element generates the same amount of heat even if different power supply voltages are supplied by inputting the input to the detection switch and controlling the on/off of the zero-cross detection switch.

By the above control, the power supply waveform to the power heating element becomes a smooth voltage rise waveform from the zero volt point of the voltage cycle of the AC power supply, and conventional problems such as generation of power supply noise can be prevented.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The power supply control device according to the present invention will be explained below by way of embodiments. (First Embodiment) FIG. 1 is a block diagram showing the first embodiment, and FIG. 2 is a waveform diagram showing the operation of the first embodiment. b is 100V.
The output of the duty control circuit when power is supplied by the power supply, c is 2
The output of the duty control circuit when power is supplied from a 40V power source, d is the waveform of the power supply voltage, e is the waveform of the power supply voltage to the power heating element when the power is 100V, and f is the waveform of the power supply voltage when the power is 240V. The configuration and operation of the first embodiment will be described below with reference to FIGS. 1 and 2. 1 is a power heating element which is a load whose resistance value does not change due to temperature changes, 2 is a triac, and 3 is a phototriac with a built-in zero-cross circuit.The triac 2 and the photo-triac with a built-in zero-cross circuit 3 constitute a zero-cross detection switch S. .

5 is a 100V/240 power supply notification means that outputs different voltage signals in conjunction with switching of the power supply voltage.
6 is an oscillation circuit that constitutes a duty control circuit, and E is an AC power source that supplies power to the power heating element 1.
It consists of a 00V power supply and a 240V power supply.

The power heating element 1 can obtain the desired amount of heat when a power supply voltage of 100V is directly applied, and the changeover switch 5 switches the output manually or automatically depending on whether the power supply voltage is 100V or 240V. Enter 6. As a result, the output of the oscillation circuit 6, which is a duty control circuit, changes. That is, when the power supply voltage is 100V, an output with an on-duty of 100% as shown in waveform diagram b in FIG. Occur.

The above output is input to the light emitting diode 3a side of the phototriac 3 with a built-in zero cross, and is output only when the voltage across the triac 3b inside the phototriac 3 is zero and the above input signal is on due to the built-in zero cross circuit. Triac 3b inside phototriac 3 is turned on. When the triac 3b inside the phototriac 3 is turned on, the gate potential of the triac 2 increases and the triac 2 becomes conductive. Furthermore, when the voltage across the triac 3b inside the phototriac 3 is zero and the input signal is off, the triac 3b inside the phototriac 3 is turned off. Therefore, for a power supply voltage such as d shown in FIG.
When the voltage is V, a voltage as shown in c in the same figure, and when it is 240 V, a voltage as shown in f in the same figure is applied to the power heating element 1.

With the above control, for example, when the power supply voltage is 240V, the energization time is reduced to 17V compared to the power supply voltage of 100V.
．． 3%, the power supplied to the power heating element 1 of both is the same, and even when the power supply voltage is 100V, the power supply is 2%.
Even when the voltage is 40V, the amount of heat generated can be matched.

(Second Embodiment) FIG. 2 is a block diagram showing the second embodiment, and FIG. 4 is a waveform diagram showing the operation of the second embodiment. , c is the output of the duty control circuit when power is supplied from a 240V power supply, d is the waveform of the power supply voltage, e is the waveform of the power supply voltage to the power heating element when the power supply is 100V, and f is the power supply voltage waveform when the same 240V power supply is used. . The configuration and operation of the second embodiment will be described below with reference to FIGS. 3 and 4. 1 is a power heating element which is a load whose resistance value does not change due to temperature changes; 2
3 is a triac, and 3 is a phototriac with a built-in zero-cross circuit.The triac 2 and the photo-triac 3 with a built-in zero-cross circuit constitute a zero-cross detection switch S.

5 is a 100V/240 power supply notification means that outputs different voltage signals in conjunction with switching of the power supply voltage.
The V changeover switch 7 is a pattern generation circuit constituting a duty control circuit.

This second embodiment differs from the first embodiment in that a pattern generation circuit 7 is used instead of the oscillation circuit as the duty control circuit, and when the power supply E is, for example, 240V, the pattern generation circuit 7 is used to notify the power supply. Based on the input from the means 5, the on/off output 2 as shown in the waveform diagram of FIG.
One pattern P is set for each cycle, and the on-duty is set to 17.3% for the entire two cycles, and the timing of the on-signal is shifted between the first cycle and the second cycle to output the signal.

Therefore, when the power supply voltage is 100V, a signal with an on-duty of 100% as shown in b shown in FIG.
In addition, when the voltage is 240V, a signal like c shown in FIG. When the voltage is 240V, power is supplied in full cycles with an on-duty of 100% as shown in e shown in FIG. 4, and when the voltage is 240V, power is supplied in discrete half cycles in alternating positive and negative directions as shown in f shown in FIG.

According to this embodiment, the power supplied to the power heating element 1 during one cycle of the on/off output does not reach the desired value, but reaches the desired value on average over two cycles. That is, the output of the pattern generation circuit 7, which is a duty control circuit, is such that the ratio of the on-output time and off-output time of a pair of adjacent ones on the time axis is the ratio of the on-output time and off-output time of a pair that was output immediately before. It is possible to prevent undesirable phenomena such as the power supply frequency and the output c of the duty control circuit becoming synchronized and the voltage of only one phase being applied to the power heating element as shown in f. This will not result in an increase in the burden on people.

[0025]

As explained above, according to the present invention, the accuracy of the zero-cross detection circuit and AC loads compatible with multiple power supply voltages are not affected by changes and fluctuations in the power supply frequency using a simple circuit configuration. It is possible to provide a power supply control device for.

Furthermore, unlike phase control, since the voltage is always applied to the AC load from zero volts of the AC cycle of the power supply, the supply voltage and power do not change instantaneously, and power supply terminal noise does not increase.

Furthermore, since an independent zero-cross detection circuit is not required, the circuit configuration becomes simple, and the reliability of the device can be improved and costs can be reduced.

Furthermore, by making the ratio of the on-output time and off-output time of a pair adjacent on the time axis different from the ratio of the on-output time and off-output time of the immediately preceding pair, an increase in the burden on the power distribution system is caused. The above effects can be obtained without any problems.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a first embodiment.

FIG. 2 is a waveform diagram of the first embodiment.

FIG. 3 is a block diagram of a second embodiment.

FIG. 4 is a waveform diagram of the second embodiment.

FIG. 5 is a waveform diagram of an unfavorable phenomenon in which the power supply frequency and the output of the duty control circuit are synchronized.

FIG. 6 is a block diagram of a conventional example.

FIG. 7 is a waveform diagram of a conventional example.

[Explanation of symbols]

1 Load (power heating element) 2 Triac 3 Phototriac with built-in zero cross circuit 4
Phototriac 5 100V/240V changeover switch (power supply notification means) 6 Oscillation circuit (duty control circuit) 7
Pattern generation circuit (duty control circuit) 8 Trigger output circuit 9 Zero cross detection circuit E AC power supply S Zero cross detection switch

Claims (2)

[Claims] 1. A power supply control device for a load used with multiple power supply voltages, which includes a built-in zero-cross detection circuit and turns on/off power supply to the load when a zero-cross of the power supply voltage is detected.
A zero-crossing detection switch that switches off, a power supply reporting means that switches the output in response to a change in the power supply voltage, and a duty control circuit that outputs an on signal with a duty varied in response to the output of the power supply reporting means, A power supply control device, characterized in that the output of the duty control circuit is input to a zero-cross detection switch to control power supply to a load. 2. The duty control circuit performs output control so that the ratio of the on output time and off output time of a pair adjacent on the output time axis is different from the ratio of the immediately preceding pair of on output time and off output time. The power supply control device according to claim 1, characterized in that: