JP2554963B2 - Power control 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 used in, for example, a switching power supply and using a plurality of magnetic amplifiers.

[0002]

2. Description of the Related Art A direct current voltage is converted into a high frequency alternating current voltage by a semiconductor switch such as an FET (Field Effect Transistor), the alternating current voltage is converted by a transformer, and then rectified and smoothed again. A DC-DC converter that extracts a DC voltage different from the original DC voltage is often used. In this converter, 2 of the transformer
By inserting a magnetic amplifier in the middle of the power supply connection path from the secondary winding to the rectifier circuit and controlling the amount of magnetic flux reset in the magnetic amplifier, the output of the magnetic amplifier is controlled by firing angle control, and after rectification and smoothing. The control of the output DC voltage is performed. Since such a DC-DC converter is often used to reduce the size and weight of the power supply, the rated output is determined according to the individual purpose. Therefore, the magnetic amplifier tends to be manufactured in small quantities and in a large variety of products, resulting in high cost. In order to prevent this, various rated outputs may be realized by connecting a plurality of magnetic amplifiers in parallel and combining standardized magnetic amplifiers.

FIG. 5 shows a power stabilizing circuit in which magnetic amplifiers are connected in parallel, and FIG. 6 shows a power stabilizing circuit in which only one is taken out. In the circuit of FIG. 6, an AC power supply 1
A series circuit including a saturable reactor 2, a power diode 3, and a load 4 is connected to. The diode 3 has an anode at the saturable reactor 2 and a resetting diode 5
Is connected to the cathode, and the anode of the diode 5 is connected to the other end of the AC power supply 1, that is, the ground terminal, via the control circuit 6. The saturable reactor 2 is formed by winding a load winding around an annular core made of a soft magnetic material having a rectangular magnetic hysteresis as shown in FIG. 7, and in a reset state, until the magnetic flux of the core is saturated. Shows a high inductance, but the current increases and the magnetic flux in the core reaches the saturation value φ.
_{When s} is reached, the inductance becomes almost zero. Here, a combination of the saturable reactor 2 and the diodes 3 and 5 is called a magnetic amplifier.

The output of the AC power supply 1 is a square wave, a current flows through the load 4 in the gate half cycle by the electromotive force in the direction of arrow g, and in the reset half cycle by the electromotive force in the direction of arrow r.
Saturable reactor 2 via control circuit 6 and diode 5
A reset voltage is applied to. Figure 7 shows the saturable reactor 2
The magnetic flux of the core is shown with the gate direction being positive, and it changes as shown by the broken line in the reset half cycle,
The magnetic flux changes from the gate direction to the reset direction and becomes φ _R. In the next gate half cycle, the magnetic flux increases to the gate direction, but almost no current flows until the magnetic flux reaches the saturation value φ _S in the gate direction. Then, when the magnetic flux reaches φ _S , the saturable reactor 2 is rapidly brought into the conducting state, and is kept conducting during the subsequent gate half cycle.

FIG. 8 shows changes in the voltage V of the AC power supply 1 and the voltage V'applied to the load 4, where the AC cycle is T, and the saturable reactor 2 saturates in the gate half cycle to cause inductance. Let τ be the time until the ignition time when becomes abruptly zero. The electric power supplied to the load 4 can be changed by shifting the firing time τ, and the electric power supplied to the load 4 is changed by the magnetic flux φ _R determined by the reset voltage applied to the saturable reactor 2 via the control circuit 6 in the reset half cycle. The arc time τ can be determined. In other words, the saturable reactor 2 is in the reset half cycle, only the amount of magnetic flux proportional to the product of the reset voltage and the reset time of the gate directions saturated
The magnetic flux is decreased from the sum value to become the magnetic flux φ _R , and the cycle is repeated from the time when the magnetic flux is increased in the gate direction by the same amount of the magnetic flux in the gate half cycle to become the saturated magnetic flux φ _S, and conduction is performed. At this time, the time τ from the beginning of the gate half cycle to conduction is proportional to φ _S −φ _R and inversely proportional to the applied voltage.

When the power stabilizing circuits using the magnetic amplifiers of FIG. 6 are connected in parallel to form the configuration shown in FIG. 5, a current corresponding to the sum of the currents flowing through the individual saturable reactors 2 is applied to the load 4. Supplied, the total rated current is the sum of the individual rated currents.

[0007]

However, in the above-mentioned configuration, it is necessary to ignite all the saturable reactors 2 at the same time, which causes unevenness in the effective cross-sectional area of the core of the saturable reactor 2 and the operation of the control circuit 6. It is necessary to eliminate misalignment. That is, if there is unevenness, the saturable reactor 2 that is ignited first concentrates the current, and due to this concentration, the applied voltage drops and the other saturable reactors 2 do not ignite, so that the load is not shared. The saturable reactor 2 which is likely to be even and has a heavy load may cause an overheat failure. In other words, the total rated current becomes smaller than the sum of the individual rated currents even if there is a slight difference in the characteristics of the core. In order to make such irregularities small enough to be ignored, it is necessary to precisely select the cores of the saturable reactor 2, resulting in poor yield and a great obstacle to mass production .

An object of the present invention is to solve the above-mentioned drawbacks and to provide a power control device in which the firing times of a plurality of magnetic amplifiers connected in parallel are always the same.

[0009]

In order to achieve the above object, a power control apparatus according to the present invention has a plurality of magnetic amplifiers having one end of a main winding connected in common. In each of the above, a balanced winding is provided, and both ends of the balanced winding are commonly connected.

[0010]

In the power control device having the above-described structure, the reset magnetic flux amounts of the magnetic amplifiers are equalized by keeping the electromotive forces generated in the balanced windings equal, so that all the connected magnetic amplifiers are fired at the same time. To do.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to the embodiments shown in FIGS. FIG. 1 is a block diagram of the first embodiment, in which an AC power supply having the same frequency, phase, and voltage is used.
One end of V1 to Vn is commonly connected to the point Q, and the other end is connected to the beginning of the main winding of the saturable reactors SR1 to SRn. The ends of the main windings of the saturable reactors SR1 to SRn are Connected to the anodes of power diodes PD1 to PDn and the cathodes of reset diodes RD1 to RDn. The cathodes of the diodes PD1 to PDn are commonly connected and connected to a point P, the points P and Q are connected via a load R, and the anodes of the diodes RD1 to RDn are not individually illustrated. It is connected to the point Q via a control resistor formed by an active element in the control circuit. Further, the saturable reactors SR1 to SRn are provided with balanced windings AB1 to ABn, and the starting ends A1 to An that generate positive electromotive force at the time of gate are commonly connected, and the terminals B1 to Bn that generate negative electromotive force are connected. Are commonly connected and connected in parallel. The saturable reactors SR1 to SRn have the same number of turns of the main winding, and the balanced windings AB1 to ABn have one turn in the embodiment.

In the steady state, all the cores of the saturable reactors SR1 to SRn are saturated with the magnetic flux in the gate direction at the end of the gate half cycle. In the reset half cycle, a control resistor and a reset diode (not shown)
A reset current flows through the main windings of the saturable reactors SR1 to SRn through RD1 to RDn, and a reset voltage is generated across the main windings. At the same time, the magnetic fluxes of the saturable reactors SR1 to SRn decrease to the opposite direction, that is, the reset direction, and increase in the reset direction. At this time, the saturable reactor SR1 ~
An electromotive force proportional to the time change of the magnetic flux is generated in the balanced windings AB1 to ABn of SRn, and since these balanced windings AB1 to ABn are connected in parallel, they are possible regardless of the difference in the effective area of the core, etc. The magnetic fluxes of the cores of the saturated reactors SR1 to SRn change equally.

At the end of the reset half cycle, the cores of the saturable reactors SR1 to SRn are reset by the common magnetic flux amount defined by the control resistors. Then, in the gate half cycle, a current flows through the main windings of the saturable reactors SR1 to SRn through the power diodes PD1 to PDn and the common load R, and the magnetic flux of the core increases in the gate direction and is eventually saturated. Here, since the self-induced electromotive forces generated in the main windings are the same and the reset magnetic flux amounts of the cores are the same, the saturable reactors SR1 to SRn are saturated at the same time and become conductive.

Until a steady state is reached, the saturable reactor
SR1 to SRn may not be saturated at the same time, but in a saturable reactor where the core is not saturated, the magnetic flux changes are equalized by the current in the balanced windings, so the reset magnetic flux amount eventually becomes equal, and the saturation occurs. It will be time to do.

Due to such operation, the saturable reactor SR
1 to SRn do not have uneven load distribution due to irregular cores, and do not overheat due to current concentration during operation.

FIG. 2 is a block diagram of the second embodiment, in which n converters constituted by connecting two magnetic amplifiers to a center tapped transformer are connected in parallel. The transformer Tr1 has a primary winding connected to a common AC power source V
The center tap of the next winding is directly connected to one end of the common load RL, and the start end is through the main winding of the saturable reactor SR1a,
It is connected to the anode of the power diode PD1a and the cathode of the reset diode RD1a, and the termination is the saturable reactor SR.
Connected to the anode of the power diode PD1b and the cathode of the reset diode RD1b via the main winding of 1b,
The cathodes of the power diodes PD1a and PD1b are connected to the other end of the load RL. Similarly, saturable reactors SR2a to SRna and SR2b to SRnb are connected to the transformers Tr2 to Trn, power diodes PD2a to PDna, PD2b to PDnb, and reset diodes RD2a to RDna and RD2b to RDnb are connected. A control resistor (not shown) is connected to the reset diodes RD1a to RDna and RD1b to RDnb between them and the center tap of the secondary winding. Furthermore, the saturable reactors SR1a to SRna have a balanced winding La1 formed by passing a wire through an annular core.
~ Lan is provided and all are connected in parallel. Similarly, the saturable reactors SR1b to SRnb also have balanced windings Lb1 to Lbn.
Are provided and are connected in parallel.

In such a structure, the saturable reactor SR is driven by the current flowing through the reset diodes RD1a to RDna.
The reset magnetic flux amount of 1a to SRna is determined, and this magnetic flux amount becomes equal by the balanced windings La1 to Lan. Similarly, the amount of reset magnetic flux of the saturable reactors SR1b to SRnb is also equal to the balanced windings Lb1 to Lb.
equalized by n. Therefore, the saturable reactor SR
1a to SRna are all fired at the same time, and similarly saturable reactor SR
Ignition from 1b to SRnb also occurs at the same time.

FIG. 3 shows a third embodiment, in which one AC power source V is connected in parallel through n power control circuits.
DC is supplied to each load RL. All n power control circuits have the same configuration, and each has two magnetic amplifiers. In the saturable reactor SR1a, one end of the main winding is connected to one end of the AC power supply V and the cathode of the diode D1a, and the other end is connected to the anode of the gate diode GD1a and the cathode of the reset diode RD1a. The other end of the AC power supply V is connected to one end of the main winding of the saturable reactor SR1b and the cathode of the diode D1b, and the other end of the main winding of the saturable reactor SR1b is connected to the gate diode GD1b.
Is connected to the anode of and the cathode of the reset diode RD1b. The cathodes of the gate diodes GD1a and GD1b are both connected to one end of the load RL, and the other end of the load RL is connected to the anodes of the diodes D1a and D1b. Similarly to the AC power source V, saturable reactors SR2a to SRna, SR2b to SRn
b, gate diode GD2a to GDna, GD2b to GDnb, reset diode RD2a to RDna, RD2b to RDnb, diode
D2a to Dna and D2b to Dnb are connected. The balanced windings La1 to Lan are respectively passed through the annular cores of the saturable reactors SR1a to SRna and connected in parallel. Similarly, the saturable reactors SR1b to SRnb also have balanced windings Lb1 to Lb.
n is passed and connected in parallel.

When the saturable reactors SR1a to SRna are conducting,
Gate diodes GD1a to GDna and diodes D1b to Dnb
A current of load RL flows through the saturable reactor.
SR1b to SRnb are reset by the current flowing through the reset diodes RD1b to RDnb, and the change in the magnetic flux is made common by the current flowing through the balanced windings Lb1 to Lbn.
Then, in the next cycle, conduction and reset are interchanged.

FIG. 4 shows a power control circuit for obtaining DC power from three-phase AC, and the outputs of n power control circuits are connected in parallel to one load RL. The main winding of the saturable reactor SRa1 + has one end connected to one end of the load RL and the other end connected to the anode of the gate diode GDa1 +, and the cathode of the gate diode GDa1 + has the output Va of the three-phase AC power supply V. It is connected to the. One end of the main winding of the saturable reactor SRa1- is connected to the other end of the load RL, the other end of the main winding is connected to the cathode of the gate diode GDa1-, and the anode of the gate diode GDa1- is the power supply. It is connected to the output Va of V. Then, depending on the polarity of the output Va, either of the saturable reactors SRa1 + and SRa1- switches. Similarly, the saturable reactors SRb1 + and SRb1- are also connected to the output Vb of the power supply V through the gate diodes GDb1 + and GDb1- and to the load RL, and the output Vc of the power supply V is also the saturable reactor SRc1 +. , SRc1- and the gate diodes GDc1 + and GDc1- are connected to the load RL. In addition, each of the saturable reactors SRa1 to SRc1 has a balanced winding La1 to Lc in which one turn is made by passing a conductor through an annular core.
1 is provided.

The above six saturable reactors SRa
Three n-phase full-wave type magnetic amplifiers using SRc are connected in parallel. Further, balanced windings La1 + to Lan + are all connected in parallel, and similarly, balanced windings La1- to Lan- are also connected in parallel. The balanced windings Lb +, Lb-, Lc +, and Lc- are also connected in parallel. Each of the saturable reactors SRa to SRc has a power supply V
In the half cycle in which the current from the core does not flow, the reset current flows through the main winding through the control circuit (not shown) .The change in the magnetic flux of the core due to this reset current is due to the parallel connection of the balanced windings. , Equal to each other. For example, the n saturable reactors SRa +, which operate with a negative output Va, are simultaneously ignited because the amount of magnetic flux is equalized by the balanced winding La +. The same applies to the saturable reactor SRa- and other saturable reactors SR.

In any of the above embodiments, in the saturable reactor in which the balanced windings are connected in parallel, the reset magnetic flux amount from the saturated magnetic flux amount is equal, and the magnetic flux change until the gate half cycle is ignited. Since they are equal, they fire at the same time.
For this reason, the conductive state is not biased among the plurality of saturable reactors, and the magnetic amplifiers can be effectively connected in parallel without fear of heating. That is, the sum of the rated currents of the individual magnetic amplifiers connected in parallel becomes the total rated current.

In the embodiment, the characteristics of the magnetic amplifiers are made uniform and the number of turns of the balanced windings is all one turn. However, this need not always be one turn, and the balanced windings may be wound by each magnetic amplifier. The number of turns may be different for each magnetic amplifier as long as the number of turns is equal to the voltage-time product applied to the magnetic amplifier. Further, the saturable reactor of the embodiment has an annular core, but a saturable reactor using a core having another shape may be used if the leakage magnetic flux is sufficiently small.

[0024]

As described above, in the power control apparatus according to the present invention, even if the magnetic amplifiers are not aligned, since the ignition times are the same, there is no risk of overheating due to uneven load sharing. A variety of ratings can be realized by combining standardized magnetic amplifiers.

[Brief description of drawings]

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

FIG. 2 is a configuration diagram of a second embodiment.

FIG. 3 is a configuration diagram of a third embodiment.

FIG. 4 is a configuration diagram of a fourth embodiment.

FIG. 5 is a circuit diagram of a power control circuit.

FIG. 6 is a circuit diagram of a power control circuit.

FIG. 7 is an operation explanatory diagram of the saturable reactor.

FIG. 8 is a diagram illustrating the operation of the core of the saturable reactor.

[Explanation of symbols]

 V AC power supply SR Saturable reactor PD Power diode RD Reset diode R, RL Load AB, L Balanced winding GD Gate diode D diode

Claims (1)

(57) [Claims] 1. A plurality of magnetic amplifiers in which one end of a main winding is commonly connected, wherein a balanced winding is provided in each of the plurality of magnetic amplifiers, and both ends of the balanced winding are commonly connected. A power control device characterized by the above.