JPS61221573A - Chopper type dc/dc converter - Google Patents

Abstract

PURPOSE:To stabilize an output in a high efficiency by inserting a saturable reactor between a switch element and an output rectifier, and varying a current flowing to the reactor in response to the output voltage. CONSTITUTION:A switch element 2 independently opens or closes by an oscillator 17. A saturable reactor 18 is inserted between the element 2 and an output rectifying and smoothing circuit having diodes 21, 22, a smoothing choke coil 23 and an output smoothing capacitor 24. A controller 27 causes a reset current to flow from the positive electrode of the capacitor 24 through the controller 27, a diode 28 and the control winding 20 of the reactor 18 to the negative electrode of the capacitor 24 in response to the detected value of an output V0 during a period of the interruption. When the element 2 is conducted, the reactor 18 blocks the input voltage for the prescribed period and is then saturated. As a result, the voltage of a pulse width for setting the voltage V0 to the prescribed value is supplied to the cathode side of the diode 21.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a chopper type DC-DC converter, and particularly to a chopper type OC-OC converter that uses a saturable reactor to stabilize the output. It is something.

[Prior Art] In a chopper type OC-OC converter, as shown in FIG. 4, a change in the output voltage 0 caused by a change in the load current IO is detected and a control circuit 9 controls the opening and closing of the switching element 2. A method for stabilizing the output is known. Furthermore, as a multi-output chopper type DC-DC converter that obtains multiple outputs from one switch element, the one shown in FIG. 5 is known. The output is stabilized by performing opening/closing control, and the output VO2 is stabilized by a series droplet.

[Problems to be solved by the invention] However, in the circuit system shown in FIG.
As becomes smaller, the current flowing through the smoothing choke coil 4 becomes discontinuous, and during the ON period of the switching element 2, the voltage across the smoothing choke coil 4 decreases and the voltage of the output VO tends to rise. There is a problem in that the on period of 2 is reduced by the control circuit 9, and in some cases, intermittent oscillation occurs. Furthermore, when a multi-output chopper type DC-DC converter as shown in FIG. The pulse width of the voltage input to 11 becomes small. Therefore, the voltage V at which the load current 102 becomes large
A problem arises in which O2 becomes less than the specified value. As a countermeasure for this, the inductance of the smoothing choke coil 4 is increased to shift the current discontinuity state to the light load side as much as possible, and a dummy resistor is installed between the output terminals 6 and 7 so that the load current 1G+ Even in the case of zero, measures have been taken to prevent the current flowing through the smooth choke coil 4 from falling below a certain predetermined value and causing the aforementioned discontinuous state. However, such a measure causes the problem of increasing the size of the smooth choke coil 4 and lowering efficiency. In addition, a three-terminal regulator 13 is used to stabilize the output vo2.
There was also the problem that the loss was large because it was used.

[Means for Solving the Problems] In order to solve the above problems, the present invention provides a saturable reactor inserted and connected between the switching element and the output rectifier circuit, and detecting the output voltage at the output terminal. The control circuit is configured to stabilize the output voltage by causing a predetermined current to flow through the saturable reactor according to the output voltage.

[Example] The present invention will be explained below with reference to Examples.

"Embodiment 1" FIG. 1 is an embodiment of a chopper type DC-DC converter according to the present invention, and shows the basic circuit configuration.

In the figure, since the switch element 2 is independently opened and closed by the oscillator 17, the load current ■
The configuration is such that it is not affected by 0. The control circuit 27 outputs a reset current from the positive terminal of the smoothing capacitor 24 according to the detected value of the output (2) during the period when the switch element is cut off. Diode 28. Saturable reactor 18
The saturable reactor 18 is magnetized in the opposite polarity to the black circle shown in the figure by passing through the control winding 20 and the negative pole of the output smoothing capacitor 24. When the switch element 2 becomes conductive, the saturable reactor 18 is oxidized to the polarity of the black circle, the magnetic flux density changes, and the saturable reactor 18 is saturated after blocking the input voltage for a predetermined period. As a result, a voltage with a pulse width that makes the output voltage VO a specified value is supplied to the cathode side of the diode 21.

When the switch element 2 is cut off, the energy accumulated in the saturable reactor 18 is released along the same path as the reset current, and the reset is performed again.

(For a detailed explanation of the operation of voltage stabilization using a saturable reactor, see, for example, the Institute of Electrical Engineers of Japan Magnetics Study Group Material MAG-84-24, 1984) "Example 2" Figure 2 shows the output from the switch element 2. An embodiment in which a multi-output chopper type OC-OC converter is constructed by combining the control method of the present invention with a chopper type DC-DC converter that stabilizes In this example, the circuit is simplified by controlling the switching element 2 by a control circuit 9 that detects the output voltage of the output terminal 6.7 and controls the period without using an independent oscillator, and , 9 are independently controlled by the saturable reactor 18. Note that the circuit operation is the same as in the embodiment.

By using this system, it has become possible to significantly increase efficiency compared to the configuration shown in FIG. 5, which is combined with the conventional series dropper system.

Embodiment 3 FIG. 3 shows another embodiment in which the present invention is applied to a multi-output chopper type DC-DC converter, in which the circuit configuration of FIG. is controlled by the three-terminal regulator 13. By adopting this configuration, the 2-terminal regulator 13 can be controlled without increasing the inductance of the output smoothing choke coil or increasing the output dummy current.
We were able to construct a multi-output chopper type DC-DC converter that can independently obtain both outputs from no-load to maximum output.

[Effect of the invention 1 As explained above, the present invention provides a multi-output chimitsuba type D with high efficiency and excellent output stability from no-load to maximum output.
It becomes possible to obtain a C-DC converter.

[Brief explanation of the drawing]

FIG. 1 is a basic circuit configuration diagram showing one embodiment of the present invention, and FIGS. 2 and 3 are configuration diagrams of embodiments showing application of the present invention to a multi-output chopper type OC-OC converter, respectively. , Figure 4 is a circuit diagram of a chopper type DC-OC converter that stabilizes the output using a conventional switch element.
FIG. 5 is a circuit diagram of a multi-output chopper type DC-DC converter having an output whose output is stabilized by a conventional switch element and an output whose output is stabilized by a series dropper. 1...DC assertion, 2...Switch element, 18...
Saturable reactor, 19... Load winding of saturable reactor, 20... Control winding of saturable reactor, 27.
...Control circuit. $1 dream'? Turning f surface l/′! Indication of f4 side 45 side case 1985 Patent application No. 55466 Title of invention Relationship with chopper type DC-DC converter correction case Patent applicant

Claims (1)

[Claims] 1. A DC power source that connects one or more rectifier circuits to a switch element connected in series with a DC power source to take out one or more outputs.
A DC converter characterized by being composed of the following parts. (a) A saturable reactor inserted and connected between the switch element and the output rectifier circuit (b) Detects the output voltage, and outputs a predetermined current through the saturable reactor according to the output voltage. A control circuit 2 for stabilizing voltage is provided with a control winding that is wound around the same core of the saturable reactor, one end of which is connected to the control circuit through a diode, and the other end of which is connected to the negative pole of the DC power supply. A chopper type DC-DC converter according to claim 1. 3. DC-DC in which one or more rectifier circuits are connected to each of at least one switch element connected in series with a DC power source, and two or more outputs are taken out from at least one of the switch elements. In the converter,
Chopper type DC-D characterized by having the following parts:
C converter. (a) A saturable reactor inserted and connected between the switch element and the output rectifier circuit (b) Detects the output voltage and flows a predetermined current through the saturable reactor according to the output voltage to adjust the output voltage. A control circuit 4 for stabilization, at least one output of the two or more outputs is stabilized by the switch element, and at least one other output is stabilized by a circuit having the saturable reactor and the control circuit. 4. The chopper type DC-DC converter according to claim 3, wherein the chopper type DC-DC converter is configured to stabilize the output.