JP3493355B2 - Capacitor type pressure regulator - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an AC pressure regulator.

[0002]

2. Description of the Related Art An AC voltage regulator is a power supply device that supplies an AC power supply whose voltage is variable. As a conventional AC pressure regulator, there are an electromagnetic coil type and a capacitor voltage dividing type.

[0003]

The electromagnetic coil type AC voltage regulator has a problem that it is heavy and bulky for general equipment. The capacitor voltage dividing type AC voltage regulator has a problem that a desired voltage ratio cannot be obtained unless a capacitor having a considerably large capacity with respect to a capacity of a load is used. Further, in the case of an inductive load, there is a problem that resonance will occur unless a capacitor having a considerably large capacity is used.

Therefore, an object of the present invention is to realize a capacitor type pressure regulator which is light and compact and which can easily set a desired voltage.

[0005]

As shown in FIG. 1, a capacitor type pressure regulator according to the present invention includes a series capacitor C connected in series between an AC power source V and a load, and a load connected in parallel to the load. A first voltage limiting circuit A1 and a second voltage limiting circuit A2. The first voltage limiting circuit A1
Is a first switching element A1 and a first capacitor C
It is a circuit in which 1 and 1 are connected in series. The second voltage limiting circuit A2 is a circuit in which a second switching element S2 and a second capacitor C2 are connected in series. The first switching element S1 is always conductive with respect to the current in the direction that charges the first capacitor C1 in the positive half cycle of the AC power supply, and is on / off controllable with respect to the current in other directions. It is an element. When the voltage of the first capacitor C1 exceeds the positive set voltage E1, it turns on and holds the first capacitor C1 at the set voltage, and when it drops below the set voltage E1, it turns off. The second switching element S2 is always conductive with respect to the current in the direction that charges the second capacitor C2 in the negative half cycle of the AC power supply, and on / off control is possible with respect to the current in the other directions. It is an element. When the voltage of the second capacitor C2 exceeds the negative set voltage −E2 to the negative side, the second capacitor C2 is turned on and holds the second capacitor C2 at the set voltage −E2, and rises above the set voltage −E2. It is turned off (Claim 1).

According to the above construction, in the positive half cycle of the AC power supply, the first capacitor C1 is charged through the switching element S1. When the voltage of the first capacitor C1 exceeds the positive set voltage E1, the first switching element S1 is turned on with respect to the reverse current, and the voltage of the first capacitor C1 is held at E1. As a result, the output voltage is half-wave limited up to the voltage E1 set by the first voltage limiting circuit A1.

In the negative half cycle of the AC power supply, the second capacitor C2 is charged through the second switching element S2. At the time when the voltage of the second capacitor C2 exceeds the negative set voltage −E2 on the negative side, the second switching element S2 is turned on with respect to the reverse current, and the voltage of the second capacitor C2 is −E2. Held in. As a result, the output voltage is half-wave limited with the lower limit being the voltage -E2 set by the second voltage limiting circuit A2.

As a result, the output voltage is subjected to both-wave limitation with the upper limit being the voltage E1 set by the first voltage limiting circuit A1 and the lower limit being the voltage -E2 set by the second voltage limiting circuit A2. Like The values of the set voltages E1 and -E2 can be made continuously variable (claim 2). According to this, it is possible to realize a capacitor type pressure regulator capable of continuous pressure regulation. The first capacitor and the second capacitor,
If each is an electrolytic capacitor (claim 3), capacity /
By taking advantage of the characteristic of the electrolytic capacitor that the volume ratio is large, it is possible to make a compact pressure regulator. The electrolytic capacitor has a polarity that it cannot be used for AC in general, but the voltage limiting circuit A1 is operated in the positive half cycle of the AC power supply, and the second voltage limiting circuit is operated in the negative half cycle of the AC power supply. By operating A2, this drawback is avoided.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. FIG. 2 is a circuit diagram of the capacitor type pressure regulator (full wave type) of the present invention. A capacitor C is connected in series with an AC power source, and a first voltage limiting circuit A1 and a second voltage limiting circuit A2 are respectively connected in parallel on the output side of the capacitor C and are connected to an output terminal. A load ZL is connected to the output terminal.

The first voltage limiting circuit A1 is a circuit for limiting the voltage of the positive half cycle, and the electrolytic capacitor C1 is connected in series to the switching transistor Q1.
The polarity of the switching transistor Q1 is the capacitor C
Is the collector and the side connected to the electrolytic capacitor C1 is the emitter. Switching transistor Q1
A diode D1 is connected in parallel between the emitter and collector of the. The other end of the electrolytic capacitor C1 is grounded. A constant voltage diode ZD1 is connected between the base of the switching transistor Q1 and the resistance voltage dividing point a. The resistance voltage dividing point a is at a connection point of the resistors R11 and R12 connected in parallel with the electrolytic capacitor C1. R12 is continuously variable.

The second voltage limiting circuit A2 is a circuit for limiting the voltage of the negative half cycle, and the electrolytic capacitor C2 is connected in series to the switching transistor Q2.
The polarity of the switching transistor Q2 is the capacitor C
The side connected to is the collector, and the side connected to the electrolytic capacitor C2 is the emitter. Switching transistor Q2
A diode D2 is connected in parallel between the emitter and collector of the. One end of the electrolytic capacitor C2 is grounded. A constant voltage diode ZD2 is connected between the base of the switching transistor Q2 and the resistance voltage dividing point b. The resistance dividing point b is at a connection point of the resistors R21 and R22 connected in parallel with the electrolytic capacitor C2. R22 is continuously variable.

The switching transistors Q1 and Q2 are
Q1 is a PNP transistor and Q2 is an NPN transistor. The electrolytic capacitor C1 has a positive electrode connected to the switching transistor Q1, and the electrolytic capacitor C2 has a negative electrode connected to the switching transistor Q2. The diode D1 is connected so as to charge the electrolytic capacitor C1 in a positive half cycle, and the diode D2 is connected so as to charge the electrolytic capacitor C2 in a negative half cycle. The constant voltage diode ZD1 has a positive electrode on the base side of the switching transistor Q1, and the constant voltage diode ZD2 has a negative electrode on the base side of the switching transistor Q2. The positive voltage of the constant voltage diode ZD1 is written as E1, and the negative voltage of the constant voltage diode ZD2 is written as -E2. The voltages E1, -E2 can be continuously set by resistors R12, R22, respectively.

As an example of the element constants of the above circuit,
Capacitor C = 20μF, electrolytic capacitor C1 = 100μF,
The electrolytic capacitor C2 = 100 μF. The operation of the above capacitor pressure regulator will be described. FIG. 3 is a waveform diagram of the power supply voltage V, the voltage V1 across the electrolytic capacitor C1, the voltage V2 across the electrolytic capacitor C2, and the voltage across the output terminals (referred to as output voltage) V3. The abscissa indicates t. Power supply voltage V
The positive half cycle of P1, P2 ,. ． ． , The negative half cycle of the power supply voltage V is represented by N1, N2 ,. ． ． It is represented by.

It is assumed that the power is turned on at t = 0. The electrolytic capacitor C1 starts charging from the first positive half cycle P1 through the diode D1, but has a long time constant,
It is assumed that the voltage V1 of the electrolytic capacitor C1 does not reach the voltage E1 in the positive half cycle P1. The output voltage V3 is
It has the same waveform as the voltage V1 of the electrolytic capacitor C1 (Fig. 3
(See (b) (d)). In the negative half cycle N1, diode D2
Through this, the electrolytic capacitor C2 is charged. Also in this case, in the negative half cycle N1, the voltage V2 of the electrolytic capacitor C2
Shall not reach the voltage -E2. Output voltage V3
Has the same waveform as the voltage V2 of the electrolytic capacitor C2 (see FIGS. 3 (c) and 3 (d)).

In the next few positive half cycles, charging of the electrolytic capacitor C1 is resumed. In the middle of these half cycles, the voltage V1 of the electrolytic capacitor C1 changes to the voltage E1.
Reach At this point, switching transistor Q1
The base-emitter of the transistor becomes conductive, and the switching transistor Q1 is turned on. As a result, the electrolytic capacitor C1
Of the voltage V1 is maintained at the set voltage E1. Also, the collector voltage of the switching transistor Q1, that is, the output voltage V3, has the upper limit of the set voltage E1.

In the next few negative half cycles, charging of electrolytic capacitor C2 is resumed. In the middle of these half cycles, the voltage V2 of the electrolytic capacitor C2 is equal to the voltage -E.
Reach 2 At this point, switching transistor Q2
The base-emitter is electrically connected, and the switching transistor Q2 is turned on. As a result, the electrolytic capacitor C2
The voltage V2 of is maintained at the set voltage -E2. Further, the collector voltage of the switching transistor Q2, that is, the output voltage V3 also has the lower limit of the set voltage −E2.

In the cycle in which the steady state is reached, the output voltage V3 oscillates in an alternating current with the set voltage E1 as the upper limit and the set voltage −E2 as the lower limit. As described above, the power supply voltage V
The upper and lower limits can be set. The upper limit voltage and the lower limit voltage can be adjusted by adjusting the resistors R12 and R22, or the constant voltage diode ZD.
1, determined by setting the breakdown voltage of ZD2. Although the embodiment of the invention has been described above, the embodiment of the invention is not limited to the above embodiment. For example, if a capacitor type pressure regulator (half-wave type) is to be realized, only one of the first voltage limiting circuit A1 and the second voltage limiting circuit A2 in FIG. 2 may be adopted. Other various modifications can be made within the scope of the present invention.

[0018]

As described above, according to the present invention, the positive setting voltage set by the first voltage limiting circuit is the upper limit, and the negative setting voltage set by the second voltage limiting circuit is the lower limit. The output voltage can be set. The voltage limiting circuit is a voltage source,
Since it can be easily configured with a switching element and an electrolytic capacitor, a compact and lightweight capacitor type pressure regulator can be realized.

[Brief description of drawings]

FIG. 1 is a circuit configuration diagram for explaining the principle of a capacitor type pressure regulator of the present invention.

FIG. 2 is a specific circuit diagram of the capacitor type pressure regulator of the present invention.

FIG. 3 is a waveform diagram of a power supply voltage V, a voltage V1 of an electrolytic capacitor C1, a voltage V2 of an electrolytic capacitor C2, and an output voltage V3.

[Explanation of symbols]

C capacitor C1 electrolytic capacitor C2 electrolytic capacitor D1 diode D2 diode Q1 switching transistor Q2 switching transistor ZD1 constant voltage diode ZD2 constant voltage diode ZL load

Claims (3)

(57) [Claims] 1. A serial capacitor connected in series between an AC power source and a load, and a first voltage limiting circuit and a second voltage limiting circuit connected in parallel to the load, respectively. The first voltage limiting circuit is a circuit in which a first switching element and a first capacitor are connected in series, and the second voltage limiting circuit is a second switching element and a second capacitor in series. In the connected circuit, the first switching element is always conducting for a current in a direction that charges the first capacitor in a positive half cycle of the AC power supply, and for a current in another direction, It is an element that can be controlled to be turned on and off, and is turned on when the voltage of the first capacitor exceeds a positive set voltage and holds the first capacitor at the positive set voltage, and falls below the positive set voltage. At some point The second switching element is an element that is always conductive with respect to a current in a direction that charges the second capacitor in a negative half cycle of an AC power supply, and is on / off controllable with respect to a current in another direction. The voltage of the second capacitor is turned on when the voltage exceeds the negative setting voltage on the negative side, the second capacitor is held at the negative setting voltage, and the voltage rises above the negative setting voltage. Capacitor type pressure regulator, which is turned off at. 2. The capacitor type pressure regulator according to claim 1, wherein the values of the positive set voltage and the negative set voltage are continuously variable. 3. The capacitor type pressure regulator according to claim 1, wherein each of the first capacitor and the second capacitor is an electrolytic capacitor.