JP2001134328A - Method for controlling ac power voltage and power source device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an AC power voltage controlling method capable of optionally reducing power to be supplied to a load side while extremely suppressing switching noise. SOLUTION: When the (2N+1) half-wave length (N: natural number) of input AC power voltage is defined as one period T, control for thinning out only half-wave length components allocated in previously determined order out of half-wave length components included in one period T is executed to obtain output AC power voltage.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an AC power supply voltage control method and a power supply device capable of arbitrarily reducing an AC power supply voltage supplied from an AC power supply and outputting the AC power supply voltage to a load side.

[0002]

2. Description of the Related Art Conventionally, as a method of controlling an AC power supply voltage for arbitrarily reducing (reducing) an AC power supply voltage supplied from an AC power supply and outputting the AC power supply voltage to a load side, an energizing time within one half wavelength is used. Was changed by phase control. An outline of a specific example of the phase control will be described. For example, a thyristor is interposed in one of the AC lines. Then, in each half wavelength of the AC voltage waveform, the time from the first zero-cross point is measured, and when a predetermined time is reached, the thyristor is turned on. The thyristor automatically turns off at the next zero-cross point,
The AC power supply voltage is supplied to the load side only for a part of the time during each half wavelength. Therefore, by changing the predetermined time from the first zero cross point of the half wavelength of the AC power supply voltage, the AC power supplied to the load side can be arbitrarily reduced (reduced).

[0003]

However, in the conventional method of controlling the AC power supply voltage, the thyristor is turned on in the middle of a half wavelength, that is, in a state where the AC power supply voltage is not zero. Has occurred, which is transmitted to the load side and adversely affects electrical equipment and the like, causing a problem of causing malfunction and failure. SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to solve the above-described problems, and an object of the present invention is to provide an AC power supply voltage control method and a power supply device capable of arbitrarily reducing power to a load side while keeping switching noise extremely low. It is in.

[0004]

That is, according to the method for controlling an AC power supply voltage according to the first aspect of the present invention, 2N + 1 half wavelength (N: is a natural number) of the input AC power supply voltage is set to one.
It is characterized in that a control is performed by thinning out only one half wavelength in a predetermined order among the half wavelengths included in the one cycle to obtain an AC power supply voltage for output. According to this, the power to the load side can be arbitrarily reduced stepwise by changing the number of half wavelengths included in one cycle. Further, the switching noise does not occur at the midpoint of the half wavelength as in the conventional example, so that the switching noise is extremely small. Also, since the number of half wavelengths included in one cycle is an odd number,
The thinned-out half wavelength is distributed to the positive polarity side and the negative polarity side for each cycle. For this reason, the period of thinning out to one polarity side is not biased, so that a well-balanced AC power supply voltage control method is provided for the commercial power supply side. Specifically, if the one cycle is equivalent to five and a half wavelengths, it is possible to reduce the power wasted on the load side while securing the minimum required power on the load side.

According to a third aspect of the present invention, there is provided a power supply device comprising: a switch disposed between an AC power supply and a load; and a synchronous means synchronized with a half wavelength of an AC power supply voltage input from the AC power supply. A synchronous pulse generator that outputs a pulse,
A 2N + 1-ary (N: is a natural number) counting operation is performed based on the synchronization pulse, and the switching means is turned off by one half wavelength of the AC power supply voltage every time the count value reaches a predetermined count value. And a counter section for outputting a control signal to be in a state. With this configuration, the above-described method of controlling the AC power supply voltage can be performed.

According to a fourth aspect of the present invention, there is provided a power supply apparatus comprising: 2N + 1 switch means disposed between one AC power supply and 2N + 1 loads; and AC power supplied from the AC power supply. A synchronization pulse generator that outputs a synchronization pulse synchronized with a half wavelength of the power supply voltage, performs a 2N + 1-ary (N: is a natural number) counting operation based on the synchronization pulse, and counts the count value each time the count value is reached. A counter unit for sequentially outputting the control signal that is turned off by one half wavelength of the AC power supply voltage to the switch means associated in advance is provided. Further, with this configuration, as a result of half-waves of the AC power supply voltage for each load being thinned out sequentially in a state of being shifted in phase by half-wavelength, when viewed in time units for each half-wavelength, 2N + 1 loads are obtained. The number of half-wavelengths of the AC power supply voltage output as a whole is always 2N half-wavelengths as a whole. Therefore, when viewed from the supply side of the commercial power supply, this is the same as the case where 2N loads are connected without thinning-out for half a wavelength, and the supplied power is balanced. Specifically, the counter section may be configured to perform a quinary counting operation.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a method for controlling an AC power supply voltage and a power supply device according to the present invention will be described below with reference to the accompanying drawings. The supply source of the AC power supply voltage is, for example, a single-phase commercial power supply, but it is needless to say that the present invention is not limited to this and can be applied to a three-phase commercial power supply. (First Embodiment) First, a basic concept of a method for controlling an AC power supply voltage according to the present embodiment will be described with reference to FIG. As shown in FIG. 1, 2N + 1 half wavelengths (N: is a natural number) of an input AC power supply voltage (also referred to simply as an input AC voltage, which is a single phase as an example).
Since it is 2, five half-wavelengths) are defined as one cycle (T), and control is performed to thin out only half-wavelengths in a predetermined order (fifth as an example) of half-wavelengths included in one cycle T. . As a result, the output AC power supply voltage (also simply referred to as output AC voltage) is thinned out for the last half wavelength (indicated by a dotted line) of each cycle T, and the power supplied to the load side is reduced by that amount. . Moreover, since there is no switching operation in the middle of a half wavelength as in the prior art, switching noise is extremely small, and the number of half wavelengths included in one cycle T is always an odd number, so that it is thinned out every cycle T. The polarity of the half wavelength changes. Therefore, compared with the case where the thinned-out half wavelengths always have the same polarity, a well-balanced half-wavelength thinning-out operation can be performed from the side of supplying the AC power supply voltage (an electric power company or the like).

Next, a power supply device that can realize the method of controlling the AC power supply voltage will be described with reference to FIGS.
First, the configuration of the power supply device 10 will be described. Switch means 14 is interposed in one of a pair of power supply lines connected to the AC power supply 12. As a result, the switch means 14 is arranged between the AC power supply 12 and the load 16. As the switch means 14, for example, a thyristor, a GTO, or an SSR (solid state relay) can be considered. In the present embodiment, an SSR is used in consideration of controllability.

The function of this SSR is as follows. For example, as shown in FIG. 1, when a control signal is not input to the gate, the input AC voltage is always on and the input AC voltage is output to the load side as an output AC voltage. When a control signal is input to the gate, the thinning operation is started from the wavelength including the first zero-cross point during the application of the control signal (that is, the supply of the output AC voltage to the load side is stopped), It has a function that a thinning operation is performed for a half wavelength up to the first zero cross point after the input of the control signal is completed. Therefore, the AC voltage is supplied to the load side from a half wavelength starting from the first zero-cross point after the input of the control signal is completed. The relationship between the input of the control signal and the on / off state may be reversed (the SSR is turned on by the input of the control signal). In this case, the polarity of the control signal must be inverted. Of course. Further, as the load, a motor that operates with a general AC voltage, an electric device having the motor, an AC / AC power supply device that inputs an AC voltage, and an AC / DC power supply device may be used.

The power supply section 18 has a function of generating a DC power supply or the like used in an internal circuit, which will be described later, based on an input AC voltage from the AC power supply 12. Although not shown, for example, the power supply unit 18 is based on a step-down circuit using a transformer, a rectifying and smoothing circuit that rectifies and smoothes a low-voltage AC voltage output from the step-down circuit, and a smoothed DC voltage. Each voltage generating a stabilized predetermined DC voltage (a voltage such as 5 V or 12 V) is constituted by a secondary-side individual power supply circuit. Usually, a series-type power supply circuit having a simple circuit configuration is often used as the secondary-side individual power supply circuit.

The synchronizing pulse generator 20 has a function of outputting a synchronizing pulse synchronized with a half wavelength of the input AC voltage from the AC power supply 12. As an example, the synchronous pulse generator 20 includes, as an example, a rectifier circuit that performs full-wave rectification of the stepped-down low-voltage AC voltage generated by the power supply unit 18, and a rectangular wave that can process a pulsating current output from the rectifier circuit in a subsequent-stage counter unit. And a comparator circuit for waveform shaping. In addition, when the rectifier circuit in the power supply unit 18 is a full-wave rectifier circuit, the output from the full-wave rectifier circuit may be shaped into a rectangular wave. The counter section 22 repeats a 2N + 1-ary (N: is a natural number) counting operation for determining one cycle T based on the synchronization pulse generated by the synchronization pulse generation section 20. Then, every time the count value reaches a predetermined count value, the switch means 14 outputs a control signal that is turned off for one half wavelength of the AC power supply voltage for one pulse (for example, for one half wavelength of the input AC voltage). Length). This control signal is input to the gate of the switch means 14. In FIG. 1, the counter section 22 operates as a quinary counter.

With this configuration, when an input AC voltage is input from an external AC power supply 12, the power supply device 10 sets five periods of the input AC voltage as one cycle T as shown in FIG. Only one pulse of the control signal is output during the period T, and only the fifth half wavelength out of the five half wavelengths included in one period T of the output AC voltage is thinned out.

(Second Embodiment) First, the basic concept of the method for controlling the AC power supply voltage according to the present embodiment is that an AC power supply is connected to 2N + 1 loads connected in parallel to a power supply line of one AC power supply. When the power supply voltage is supplied, when looking at each load, 2N + 1 half wavelength of the input AC power supply voltage is defined as one cycle T, and during this one cycle T, only one control signal is output, and the output AC voltage This is a control method similar to the first embodiment in which only one half-wavelength in a predetermined order among the half-wavelengths included in one cycle T is thinned out, but the characteristic part is the output to each load. The half-wavelength thinned out of the AC voltage is shifted in phase by half-wavelength.

According to this control method, the half-wavelength of the AC power supply voltage supplied to any one of the 2N + 1 loads is always decimated when viewed in time units for each half-wavelength. And the whole wavelength is always 2N half wavelengths. In other words, the apparent load seen from the external AC power supply (for example, the supply side of the commercial power supply) is 2N and becomes 1N.
The number of loads is reduced by the number, and the power supplied to the load is reduced by that amount. In addition, when 2N + 1 loads are considered as one load, an external AC power supply can be provided even if the output AC voltage is thinned out, as compared with the case of one load as in the first embodiment. There is no period in which no voltage is supplied from the power supply (quiet period). Therefore, the power supplied from the supply side of the commercial power does not become unbalanced.

Next, a power supply device that can realize the method of controlling the AC power supply voltage will be described with reference to FIGS.
First, the configuration of the power supply device 30 will be described. The same components as those of the power supply device 10 according to the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted. A pair of power supply lines connected to one AC power supply 12 have 2N + 1 loads (for example, N = 2 and a total of 5 loads) 16a to 16e.
Are connected in parallel. Then, each of the loads 16a to 16
On one of the power supply lines connected to e, five switch means 14a to 14e are provided one by one in total. The switch means 14a to 14e are, for example, SSR
You are using Further, similarly to the power supply device 10 of the first embodiment, the power supply unit 18 includes a power supply unit 18 and a synchronization pulse generation unit 20.

The counter unit 32 is based on the synchronization pulse and has a base of 2N + 1 (N is a natural number, for example, N = 2 and quinary).
Perform count operation. Each time a count value is reached, that is, each time the count value changes, a control signal a to a control signal e are sequentially output to the switch means 14a to 14e corresponding to each count value in advance. More specifically, the counter unit 32 includes the switch units 14a to 14e.
The control signal a to the control signal e can be outputted independently to each other. As shown in FIG. 3, each of the control signals a to e is sequentially changed in length for one cycle of the synchronization pulse, that is, for half a wavelength of the input AC voltage, every time the count value of the counter unit 32 changes. It is output from the counter unit 32 as a pulse signal having a pulse width of a length. Therefore,
The control signals a to e to the respective switch means 14a to 14e are in a state where the phases are shifted from each other by a half wavelength of the AC power supply voltage.

With this configuration, each load 1 of the power supply 30 is
Output AC voltage a to output AC voltage e for 6a to 16e
Is as shown in FIG. That is, assuming that one half T of the input AC voltage is one cycle T, the output AC power supply voltage (output AC voltage) a supplied to the first load 16a has a voltage corresponding to the first half wavelength in one cycle T. In the output AC voltage b supplied to the second load 16b, the voltage corresponding to the second half wavelength in one cycle T is thinned out, and in the output AC voltage c supplied to the third load 16c, one cycle is applied. In the output AC voltage d supplied to the fourth load 16d, the voltage for the fourth half wavelength in one cycle T is thinned out, and the voltage for the third half wavelength in T is thinned out. In the output AC voltage e supplied to the load 16e, the voltage for the last fifth half wavelength in one cycle T is thinned out. As a result, in each half wavelength of one cycle T of the input AC voltage, the voltage waveform of one output AC voltage is always thinned out, and the AC power is not supplied to one load to which the output AC voltage is supplied. , And the output AC power supply voltage is supplied only to the other four loads.

The power supply units 10 and 3 of each of the above-described embodiments
At 0, the output AC voltage is necessarily thinned by one half wavelength during one cycle T. Therefore, regardless of the form of the load, the power supplied to the uniform load can be arbitrarily reduced in steps. Therefore, the power consumption of the electric equipment can be reduced by supplying the AC power supply voltage to the existing electric equipment through the power supply devices 10 and 30 without modifying the electric equipment itself. It is possible to surely reduce the amount.

Normally, in an electric circuit used in such an electric device, even if the input AC voltage fluctuates to some extent, a voltage margin is set so that the power supply voltage used internally does not fluctuate. It is designed to have. However, at present, the margin is wasted as surplus energy. For example, in the case of electric equipment other than electric equipment in which input electric energy is directly converted into heat energy by a heater or the like, such as electric equipment such as an electric stove or an electric stove, generally, first, the input AC The voltage is rectified by a primary-side rectifier circuit and then smoothed by a primary-side smoothing circuit. Then, the smoothed high voltage DC voltage (about 140 volts) is switched and converted back into a high voltage AC voltage, and various low voltage AC voltages are generated on the secondary winding side using a transformer. Let it. Each low-voltage AC voltage is rectified and smoothed on the secondary side to generate various desired DC voltages, which are used in an internal circuit of an electric device.

The input AC voltage is converted to generate a desired internal voltage, and in the case of an electric device to be used, it is usually designed with a considerable margin against the fluctuation of the input AC voltage. Even if a half wavelength of the input AC voltage is thinned out by one half wavelength at a predetermined cycle, the fluctuation is absorbed in the rectification / smoothing part on the primary side and the rectification / smoothing part on the secondary side. In most cases, there is no problem in operation. In the case of electrical equipment such as vending machines that have a compressor inside,
It has a built-in electric motor to drive the compressor,
Even if this electric motor operates with a commercial AC power supply, even if a half wavelength of the AC voltage waveform is thinned out by a predetermined wavelength at a predetermined period, the rotor of the electric motor is driven by its own inertial force. In most cases, the operation of driving the compressor does not cause any problem at all. Therefore, the AC power controlled by the AC power supply voltage control method can be applied to most electric devices which have no problem in operation even if the half wavelength of the input AC voltage is thinned by one half wavelength at a predetermined cycle. By supplying a voltage and an AC power supply via the power supply device according to the present invention, it is possible to reliably reduce the power consumption of most electric devices. In addition, since the thinned-out half wavelengths are alternately distributed to the AC positive electrode side and the AC negative electrode side, balanced thinning is performed when viewed from an external AC power supply. In addition, one half wavelength in an odd number of half-waves of the input AC voltage is defined as one cycle, and one half-wavelength in one cycle is thinned out. However, if one cycle is too long, the reduction in power consumption due to the thinning is reduced. If the effect is weakened, on the other hand, if one cycle is too short, the rate of reduction of the power supplied to the load side of the electric equipment or the like will be too large, adversely affecting the operation of the load. As a result of an experiment in consideration of these circumstances, it is considered that when one cycle corresponds to five and a half wavelengths, the power supplied to the load side can be reduced as far as the load operation is not affected.

[0021]

According to the AC power supply voltage control method and the power supply apparatus of the present invention, the power to the load side can be arbitrarily reduced stepwise by changing the number of half wavelengths included in one cycle. Further, the switching noise does not occur at the midpoint of the half wavelength as in the conventional example, so that the switching noise is extremely small. Further, since the number of half wavelengths included in one cycle is an odd number, the thinned-out half wavelength is distributed to the positive polarity side and the negative polarity side for each cycle. For this reason, since the period of thinning out to one polarity side is not biased, there is an effect that a well-balanced AC power supply voltage control method is provided for the commercial power supply side.

[Brief description of the drawings]

FIG. 1 is a timing chart for explaining the operation of a first embodiment of a method for controlling an AC power supply voltage according to the present invention (in the case of a quinary count as an example).

FIG. 2 is a block diagram for explaining a configuration of a power supply device that realizes the method of controlling an AC power supply voltage of FIG. 1;

FIG. 3 is a timing chart for explaining the operation of the second embodiment of the method for controlling an AC power supply voltage according to the present invention (as an example, when there are five loads and a quinary count).

FIG. 4 is a block diagram for describing a configuration of a power supply device that realizes the method of controlling an AC power supply voltage in FIG. 3;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Power supply unit 12 AC power supply 14 Switching means 16 Load 18 Power supply unit 20 Synchronous pulse generation unit 22 Counter unit

Claims (5)

[Claims] 1. One cycle is defined as 2N + 1 half wavelength (N: is a natural number) of the input AC power supply voltage, and only one half wavelength in a predetermined order among the half wavelengths included in the one cycle is used. A method for controlling an AC power supply voltage, wherein thinning control is performed to obtain an AC power supply voltage for output. 2. The method of controlling an AC power supply voltage according to claim 1, wherein said one cycle is equivalent to five half wavelengths. 3. A switching means arranged between an AC power supply and a load; a synchronization pulse generator for outputting a synchronization pulse synchronized with a half wavelength of the AC power supply voltage input from the AC power supply; 2N + 1 (N is a natural number) counting operation, and the switch means is turned off by one half wavelength of the AC power supply voltage every time the count value reaches a predetermined count value. A power supply device comprising: a counter unit that outputs a control signal. 4. A power supply system comprising: 2N + 1 switch means disposed between one AC power supply and 2N + 1 loads; and outputs a synchronization pulse synchronized with a half wavelength of an AC power supply voltage inputted from the AC power supply. A synchronous pulse generating unit, performing a 2N + 1-ary (N: is a natural number) counting operation based on the synchronous pulse, and successively turning on the alternating current to the switch means previously associated with the count value at each count value A power supply device comprising: a counter unit that outputs a control signal that is turned off by one half wavelength of the power supply voltage. 5. The power supply device according to claim 3, wherein the counter section performs a quinary counting operation.