JPH01209957A - Dc/dc converter - Google Patents

Abstract

PURPOSE:To reduce the size and weight of a DC/DC converter by associating a set of forward type DC/DC converters utilizing the first quadrant and a set of similar converters utilizing the third quadrant. CONSTITUTION:A DC/DC converter is composed of a primary power source 1, input filters 2-3, a transistor(Tr) 4 of a switching element, a transformer 5, regenerative diodes 6, 8, a rectifying diode 7, smoothing inductance 9 and capacitance 10, a load 11, an error amplifier 17, a pulse-width controller 18, and a driver 19 as a forward type utilizing a first quadrant of the magnetization curve of the transformer 5. Further, similarly, it is composed as a forward type DC/DC converter utilizing the third quadrant to transmit power to loads 11, 15 independently by one transformer 5. As a result, the DC/DC converter in which its size and weight are reduced can be provided.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a DC/DC converter that supplies independently stabilized power to two mutually independent loads.

[Conventional technology]

In conventional DC/DC converters, when supplying independently stabilized power to mutually independent loads, two independent DC/DC converters are used to supply power to each load. In particular, when this DC/DC converter is required to be smaller and lighter, a forward type DC/DC converter is used.

FIG. 4 shows a circuit diagram of a conventional forward type DC/DC converter. In FIG. 4, (1) is a primary power source which is a power source, (2) is an inductor which constitutes an input filter, (3) is a capacitor which also constitutes an input filter, (4) is a transistor which is a switching element, (
5) is a transformer that transmits the pulsed power by transistor (4) to the load side, and (6) is a transistor (
4) is a regenerative diode that regenerates the energy of the transformer (5) when it is OFF, (7) is a rectifier diode, C81
is a regenerative diode that maintains the current in the smoothing inductance (9) when the rectifier diode (7) is OFF, and (9) is the smoothing inductance.

(1 (I is the smoothing capacitance, aJ is the load, aη is the error amplifier, αIU pulse width control circuit, (II is the driver circuit for transistor (4). (αG from 13 is the same as t1υ from (7) above) +1 for each movement
3 is a rectifier diode, a3 is a regeneration diode, 141
is the smoothing inductance, 4 is the smoothing capacitance,
ae is the load.

The operation of this forward type DC/DC converter will be described in detail using the operating waveform diagram in FIG. 5 and the magnetization characteristic diagram of the transformer in FIG. 6. The forward type DC/DC converter shown in Fig. 4 is a circuit that supplies a stably controlled DC voltage to a load aD.The voltage applied to the load aυ is compared with a reference voltage using an error amplifier αη, and the output is 08 time of transistor (4) is controlled by pulse width control circuit α barrel according to A stable DC voltage is supplied to the load. In this FIG. 4, the transistor (4) is connected to the driver circuit 0 to (b) in FIG.
) When the drive pulse shown in ) is applied, the transistor (
4) is turned on and the fifth
The voltage shown in (c) in the figure is applied from the power supply (2), and the transformer (6) is excited and moves on the B-H curve in Figure 6 from tl to C3.During this operation, the transformer (6) 5) The excitation current flowing from tl to C6 in Fig. 5(d)
Shown below. The symbols from tl to tlo shown in (-) in FIG. 5 represent the operating states at the same time as the symbols on the B-H curve in FIG. When the drive pulse shown in (b) is cut off, the transistor (4) turns off and the transformer (gahakono-
6th by discharging the excitation current flowing to the next winding.
Move from C3 to C5 on the B-H curve in the figure. Therefore, a voltage shown as <cl in FIG. 5 appears in the negative winding and the secondary winding of this transformer (5). A case will be described in which the excitation current flowing through the transformer (group) during this operation is the widest, as shown in C6 to C5 in FIG. This is the operation from time t6 to 110 shown in FIG.

The transistor (4) is connected from the driver circuit α9 to the TM module shown in FIG. 5(b). When a drive pulse of is applied, the transistor (4) turns on and the -
The voltage shown in FIG. 5(c) is applied to the next winding from the power source (1), and this transformer (5) is excited and B-H in FIG.
It is excited and moves on the curve from 15 through C3 to C8.

Also, the driver circuit ((b) in Fig. 5 transmitted from C9
) When the drive pulse shown in ) is cut off, the transistor (4
) is turned off, and the transformer (5) discharges the excitation current flowing to this secondary winding, thereby moving from C8 to tlo on the B-- curve in FIG. 6.

As a result of this series of operations, the voltage shown in FIG. 5(c) appears in the negative winding and the secondary winding (5). This sixth
The amplitude of the magnetic flux density during the operation from 5 to C8 on the B-H curve in the figure is ΔBMA! The forward type DC/DC converter is designed so that the sum of this amplitude and the residual magnetic flux density is smaller than the saturation magnetic flux density of the core constituting the transformer (5). A transformer that operates like this (5
The voltage shown in Fig. 5(c) appears in the secondary winding of ) and is converted to the voltage required for each load, and the voltage shown in (c) of Fig.
is a rectifier diode (7).

Regeneration diode (8), smoothing inductance (9),
A stable DC voltage is supplied to the load by the smoothing capacitance 11 (I, and the second load Oe includes a rectifier diode, a regenerative diode αJ, and a smoothing inductor p7X.
A stable DC voltage was supplied by rJ4J and smoothing capacitance αs.

[Problem to be solved by the invention] Such a conventional forward type DC/DCC/formula-
In a controller, the control system (error amplifier, pulse width gain circuit, driver circuit) is required to supply independently stabilized power to mutually independent loads. i- It became impossible to have it independently.

On the other hand, as a method of supplying independently stabilized power to such loads, two conventional forward-type DC/L)C converters have been used to supply power.

In such a conventional system using two forward type DC/DC converters, there has been a big problem in fully implementing the lightweight shed.

This invention was made to solve this problem, and uses one of the heaviest transformers among DC/DCC/type transformers to supply two independent loads with independently stabilized power. The purpose is to supply.

[Means to solve the problem]

The DC/DC converter according to the present invention individually detects the applied voltages applied to two independent loads, and independently transmits the respective error amplifiers, pulse width modulation circuits, drive circuits, and switch elements using one transformer. This allows the DC/DC converter to be made smaller and lighter. .

[Effect]

In the DC/DC converter in this invention.

When using the magnetization curve of the transformer of a conventional forward type DC/DC converter, from the first quadrant where B and H are positive, to the first quadrant where B and H are positive and B
and H are negative, allowing the use of third-zoom cash, and a set of forward type DC/DCs that use first-zoom cash.
By combining a DC converter and another set of forward type DC/DC converters that utilize the third quadrant, it is possible to independently transmit power to a load using one transformer.

〔Example〕

FIG. 1 is a circuit diagram of a C/DC converter () showing an embodiment of the present invention, where (l) is a primary power source serving as a power source;
(21 is an inductor that constitutes the input filter.

(3) is a capacitor that also constitutes the input filter.

(4) A transistor, which is a switching element, (5)
is a transformer that transmits the pulsed power by the transistor (4) to the load side, and (6) is the transistor (4)
A regeneration diode that uses the energy of the transformer (5) as an excuse when it is OFF, (7) is a rectifier diode, and f8) is a regeneration diode that maintains the current in the smoothing inductance (9) when the rectifier diode (7) is OFF. diode.

(9) is the smoothing inductance, the mouth α is the smoothing capacitance, ae is the load, the fin is the error amplifier, 01 is the pulse width control circuit, (19 is the driver circuit for the transistor (4). az to ae are the above (7) ) to (Same operation as 19, α2 is a rectifier diode, (13 is a regenerative diode, u4 is a smoothing inductance, α is a smoothing capacitance, ae is a load, cn is a transistor that is a switching element, and Qυ is a transistor O of
A regeneration diode that regenerates the energy of the transformer (5) during FF, (2) is an error amplifier, (to) is a pulse width control circuit, c! 4 is a driver circuit for the transistor (4).

Among these, transistor (4) 1 regeneration diode C6).

Rectifier diode (7), regeneration diode (8), smoothing ear 1" ctance (9), smoothing capacitance (IG, load aD, error amplifier fin, pulse width control circuit, driver circuit mokke transformer (5) A forward-type DC/DC converter that utilizes the first quadrant of the magnetization curve is constructed.
3° smoothing inductance Q4. The smoothing capacitance α, the load αe, the error amplifier (2), the pulse width control circuit (c), and the driver circuit constitute a forward DC/DO converter that uses the third quadrant cash of the magnetization curve of the transformer (5). do. The primary power supply (inductor (2), which constitutes the input filter, and the capacitor (3), which also constitutes the input filter) are forward type DC/DC converters that utilize the first quadrant of the magnetization curve of the transformer (5). Forward type DC/DC using converter and third quadrant
It is shared by the converter.

Transistor (4) in the primary winding of transformer (5)
The winding excited by N11. ) The winding excited by the run raster r2D is N12, and when the winding N11 is excited in the secondary winding of the transformer (5), the winding that outputs a positive voltage is N210. The winding N12 is excited. The winding that sometimes outputs a positive voltage is designated as N22.

N11 and N12 and N21 and N22 are wound in opposite directions. The primary winding N11 of this transformer (5)
is the cathode of transistor (4) and diode C11).

The transistor a1 and the cathode of the diode (6) are connected to N12, and the rectifier diode (7) is connected to the secondary winding N21.
)but.

A rectifying diode f13 is connected to N22.

The operation of this DC/DC converter will be described in detail using the operating waveform diagram in FIG. 2 and the magnetization characteristic diagram of the transformer in FIG. 3.

In FIG. 1, when the drive pulse shown in FIG. 2(c) is applied from the driver circuit as to the transistor (4), the transistor (4) is turned on and the transformer (
5) to the negative winding (between N11 and N12) of (a) in Fig.
) is applied, and this transformer (5) is excited and moves on the B-H curve in FIG. 3 from tl to t3. The excitation current flowing through the transformer (5) at this time is shown from tl to 13 in FIG. 2(e). The symbols from tl to 10 shown in FIG. 2(d) represent the operating state at the same time as the symbols on the B-H curve in FIG.

Next, when the drive pulse transmitted from the driver circuit (19) is cut off, the transistor (4) is turned off and the transformer (5) releases the excitation current flowing to the -order winding (N11). It moves on the curve from t3 to voltage 5. Therefore, the voltage shown in FIG. ) are shown from 13 to 15 in FIG. 2(e).

Next, when a drive pulse is transmitted from the driver circuit 0.4 to the transistor (to), the direction of the excitation current flowing through the transformer (5) is gradually reversed, and this excitation current is
) flows from t5 to 16, and is excited in the opposite direction from 15 to t6 on the B-H curve in FIG.

Next, when the drive pulse transmitted from the driver circuit is cut off, the transistor (to) is turned off and the transformer (5) releases the excitation current flowing to the -th winding (N12), resulting in B- in Figure 3. Move on the H curve from 17 to t8. Therefore, the voltage shown in FIG. 2(a) appears in the negative and secondary windings of this transformer (5). The excitation current flowing through the transformer (5) at this time is shown from tl to t8 in FIG. 2(e).

Next, when a drive pulse is again applied to the transistor (4) from the driver circuit a9, this transformer is excited and moves from t8 to t9 on the B-H curve in FIG. 3. From the operating point tlo to tl The transition time from voltage 7 to t8 is controlled so that the saturable inductors (c) and (to) each have a high impedance.

As a result of this series of operations, the voltage shown in FIG. 5(a) appears in the negative winding and the secondary winding (5). This third
The broken line of the B-H curve in the figure is the maximum permissible value of the amplitude of the magnetic flux density, which is the sum of the actual amplitude and the residual magnetic flux density (Br) at the maximum pulse width.

Because the transformer operates in this manner, it is possible to supply independently stabilized power to mutually independent loads using one transformer. As a result, it is possible to reduce the weight of the transformer, which has been an issue with compact and lightweight DC/DC converters.

〔Effect of the invention〕

In the DC/DC converter in this invention.

When using the magnetization curve of the transformer of the conventional 7-way DC/DC converter, from the first quadrant, where B and ■ are positive, to the second quadrant, where B and H are positive, and B
A set of 7-odd system DC/D that uses the first quadrant and allows the use of the third quadrant where ■ and ■ are negative.
By combining the C converter and another set of forward type DC/DC converters that utilize the third quadrant, power can be transmitted to the load independently using one transformer, which allows this DC/DC converter to be made smaller and lighter. effective.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of a DC/DC converter showing an embodiment of the present invention, FIG. 2 is an operating waveform diagram of the present invention, and FIG. 3 is a magnetization characteristic diagram of the transformer of Jin's invention. Fig. 4 is a circuit diagram of a conventional forward type DC/DC converter, Fig. 5 is an operating waveform diagram of the present invention, and Fig. 6 is a circuit diagram of a conventional forward type DC/DC converter.
The figure is a magnetization characteristic diagram of the transformer of the present invention. In the figure of Jin (υ is the primary power supply, (2) is the inductor, (3)
is a capacitor, (4) is a transistor which is a switching element, (5) is a transformer, (6) is a regenerative diode,
(7) is a rectifier diode, (8) is a regeneration diode,
(9) is a smoothing inductor, and r, , ati are smoothing capacitances. ae is the load, aW is the rectifier diode, (1:I is the regenerative diode, (14 is the smoothing inductance, ae
is the smoothing capacitance, ae is the load, and a is the error amplifier. α・ is a pulse width control circuit, Q [with] is a driver circuit,
(to) is a transistor which is a switching element, ca
n is the regenerative diode, slope is the error amplifier, (to) is the pulse width control circuit, @ is the driver circuit, c! 9 is a saturable reactor, and cIl is a saturable reactor. Note that the same reference numerals in Figure 0 indicate the same or equivalent parts.

Claims (1)

[Claims] A primary power supply that serves as a power source, an inductor connected to it that constitutes an input filter, a capacitor that also constitutes an input filter, and the middle point of the primary winding connected to this to supply a pulsed voltage to the load side. 2 to output the opposite polarity.
A transformer having a secondary winding, two transistors that are switching elements provided at both ends of the primary winding of this transformer, and two rectifier diodes each connected to the secondary winding side of the transformer, Rectifier diode is OFF
A regeneration diode connected to maintain the current in the smoothing inductance when F is on, a smoothing inductance connected in series with the rectifying diode, and the transistor connected in series with the smoothing inductance turned OFF. A saturable reactor that regenerates the excitation energy of the transformer at high speed, a smoothing capacitor connected to this so that the voltage is smoothed, and a load that requires independently stable power; A DC/DC converter that is characterized by supplying independently stabilized power to two mutually independent loads using an error amplifier that controls the supply of power, a pulse width control circuit, and a driver circuit that drives a transistor. DC converter device.