JPS60148374A - Dc/dc converter - Google Patents

Abstract

PURPOSE:To improve the efficiency of a DC/DC converter with a simple circuit configuration by returning energy stored in wiring inductance and the leakage inductance of a transformer through a diode to a power source. CONSTITUTION:A negative electrode side diode 23 and a position electrode side diode 24 connected in the polarity direction for returning energy stored in the wiring inductance 2 and the leakage reactance of a compound winding reactor 3 to a DC power source are respectively provided at positive and negative electrode sides of the reactors 3. A whiskerlike returning current is flowed in the sequence of the power source 1, the diode 23, the inductance 2, the reactor 3, the diode 24 and the power source 1, and the energy is returned to the power source 1.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field to Which the Invention Pertains) The present invention relates to a ringing choke type Do-Do converter having a means for recovering energy stored in a transformer leakage inductance.

(Prior art and its problems) A ringing choke type DC-DC converter can make the load side voltage higher or lower than the power supply side voltage. iJ1 has a wide range, so it is often used.

FIG. 1 is a circuit diagram of a conventional ringing choke type DC-DC converter. In FIG. 1, the transistor switch 5 is turned on to increase the primary current flowing from the reconnaissance power supply 1 to the primary winding of the multi-winding reactor 3, thereby transferring energy to the multi-winding reactor 3. inject. Next, by turning off the aforementioned transistor switch 5, the energy stored in the double-winding reactor 3 is injected into the smoothing capacitor 8 as a secondary current generator 2 via the rectifier diode 6. 9 is a DC negative. Further, 2 represents the leakage inductance and wiring inductance of the reactor 3 in equal numbers.

By turning the primary current on and off in this way, energy is stored in the compound winding reactor 3, and then this energy is released to the load side, but as the primary current flows, the compound winding reactor 3 The energy stored in the leakage reactance 2 of 3 is
Since the voltage is not transmitted to the load side when the transistor switch 5 is turned off, there is a risk that the transistor switch 5 will be damaged due to overvoltage unless appropriate treatment is taken. Therefore, a clamp circuit consisting of a clamp diode 11 and an energy recovery means 12 connected in series is provided to bridge this leakage inductance 2 and the multi-winding reactor 3, and the energy accumulated in the above-mentioned inductance etc. is recovered. Preferably, it is collected by means 12.

This recovered energy may be given to a resistor and consumed as heat, but if it is returned to the DC power supply 1 by the energy return means 13, the temperature of the device will not increase and the efficiency of the device will be improved. I can do it.

FIG. 2 is an operational waveform diagram showing voltages and currents at various parts in the circuit shown in FIG. 1. FIG. 2(a) shows the voltage waveform on the primary side of the double-winding reactor 3, where ■, the voltage of the DC power supply l, and ■8I the corresponding Do-1)C converter that is applied to both ends of the smoothing capacitor 8. 1 of this compound winding reactor 3 determined by the output voltage ■8 and the turns ratio of the compound winding reactor 3.
This is the induced voltage to the next side, and 12 is the voltage of the clamp circuit mentioned above. ) The solid line is the primary current wire 2 of the double winding reactor 3, and the broken line is the secondary current wire. Figure 2 (c) shows the current waveform of the clamp circuit current ■, l, and the second waveform.
Figure (d) shows the D that is present at both ends of the smoothing capacitor 8.
It shows the tlJ and pressure waveforms of o-DC converter output voltage ■8.

If the clamp voltage v1□ shown in FIG. There is a risk that all the energy will flow back into this clamp circuit on the primary side without being transferred to the secondary side, that is, without being commutated.
In order to ensure commutation, the voltage difference between the clamp circuit voltage V1□ shown in Figure 2 (a) and the primary side induced voltage V81 of the multi-winding reactor 3 must be set to a sufficiently high value. No. In addition, in the circuit shown in Fig. 1, the leakage inductance 2 of the compound winding reactor 3 including the wiring inductance
Accordingly, the whisker-shaped clamp circuit electrician 1 shown in Fig. 2 () and ) is constructed. flows into the energy recovery means 12, but as the overnight capacity of the DC-DC converter increases, the proportion of the power flowing into the energy recovery means 12 in the total power of the device also increases to 10%. Therefore, the electric power flowing into the energy recovery means 12 is converted into DC 1i by the energy return means 13, for example.
If you use it effectively by returning ¥1 to Source 1, you can earn 1:
) The efficiency of the D O'DC converter will be improved by about 10%.

Figure 3 shows a conventional ringing choke system that specifically shows these energy recovery means and return means.

- It is a circuit diagram of a Do converter. In this Figure 3, the symbols, names, uses, and functions of the DC power supply 1, wiring inductance 2, compound winding reactor 3, transistor switch 5, rectifier diode 6, smoothing capacitor 8, DC load 9, and clamp diode 11 are as follows. Since it is exactly the same as that shown in the circuit of FIG. 1, its explanation will be omitted.

In FIG. 3, the energy stored in the wiring inductance 2 and the leakage reactance of the compound winding reactor 3 is stored in a clamp capacitor 15 as an energy recovery means via a clamp diode 11. The energy stored in this clamp capacitor 15 is converted into a voltage approximately equal to II4 by a DC-DC converter 16 as an energy return means, and this DC-D.

By connecting the output side of the converter 16 in parallel to the DC power supply 1, the energy recovered and stored in the clamp capacitor 15 can be effectively used. However, as is clear from the conventional example shown in FIG. DC'-D to collect and return
The disadvantage is that the circuit becomes complicated and expensive, such as the need for an O converter 16.

(Object of the Invention) The present invention provides a method for recovering the energy stored in the inductance in the circuit without contributing to voltage conversion by using a simple circuit configuration and improving the efficiency of the device at low cost. - The purpose is to provide a DC converter.

(Summary of the Invention) The present invention provides a switch means for connecting the primary winding of a +M% line reactor, that is, a sewing machine, to a DC power supply in a ringing choke type Do-DC converter. are placed on each other at the same time.
A semiconductor switch that is turned off is provided, and a terminal on the transformer primary winding side of each semiconductor switch is connected to the transformer primary winding side terminal in order to recover the energy stored in the transformer leakage inductance when the semiconductor switch is turned off.
Each is connected to the corresponding terminal of the DC power supply either directly with a diode or via an auxiliary energy recovery circuit.

(Embodiment of the Invention) FIG. 4 is a circuit diagram showing an embodiment of the present invention, and the present invention will be explained in detail below with reference to FIG.

In FIG. 4, the primary current ■, which flows from the free current power source 1 to the primary winding of the multi-winding reactor 3, is the positive side transistor provided on the positive and negative sides of the multi-winding reactor 3. By turning on the switch 21 and the negative transistor switch 22 at the same time, the energy increases and the energy is injected into the multi-winding reactor 3. 2 is an inductance expressed in equal numbers of wiring inductance and reactor leakage inductance, and as the primary current flows, energy is naturally stored in this inductance 2 as well. Next, when the above-mentioned positive and negative side transistor switches 21 and 22 are turned off simultaneously, the energy stored in the double-winding reactor 3 is injected into the smoothing capacitor 8 via the rectifier diode 6 as a secondary current generator, resulting in direct current. DC power is supplied to the load 9. When this primary current is turned off, the energy accumulated in the wiring inductance 2 and the leakage reactance of the compound winding reactor 3 is not transmitted to the square tube side, so it must be recovered and disposed of accordingly. Must be.

In the present invention, a negative side diode 23 and a positive side diode 24 are provided on the positive side and negative side of the compound winding reactor 3, respectively, and are connected in the polar direction so that the above-mentioned energy can be returned to the DC power supply 1. , DC power supply 1
→ Negative side diode 23 → Inductance 2 → Compound winding reactor 3 → Positive side diode 24 → Whisker-shaped return current wire 2. flows and the energy is returned to the DC power source 1. FIG. 5 is an operating waveform diagram showing voltages and currents at various parts in the circuit shown in FIG. FIG. 5(a) shows the voltage waveform on the primary side of the double-winding reactor 3, where ■, the voltage of the DC power supply 1, and ■8. is the voltage across the smoothing capacitor 8 and the induced voltage to the primary side of the multi-winding reactor 3 which is suspended between #C%+(-) of the multi-winding reactor 3, and V22Q shown by the solid line is the negative pole. This is the collector terminal voltage of the transistor switch 22 on the side, and V21E shown by a broken line is the -L pressure wave shadow of the voltage on the emitter terminal of the transistor switch 21 on the positive side. The waveform of , is a solid line, and the secondary current flow of the same reactor 3.

The waveform of is shown by the dashed line. FIG. 5(c) shows the current waveform of the return current generator 24 recovered to the DC power source 1, and
Figure (d) shows the D that is present at both ends of the smoothing capacitor 8.
The voltage waveform of the o-DC converter output voltage 8 is shown.

In order to turn off the positive and negative side transistor switches 21 and 22 at the same time and transfer or commutate the energy stored in the double winding reactor 3 to the secondary winding side, the steps shown in FIG. As shown in , from the output voltage ■8 and the @ line ratio of the multi-winding reactor 3, the voltage v1 of the DC power supply l must be higher than the voltage ■81 induced to the primary side of the reactor 3. . In other words, the commutation condition is Vt>
It is Vat.

Ringing choke type DC-1)a as shown in Figure 4
The relationship between the power supply voltage v1 and the output voltage v11 of the converter is as follows: the switching duty of the switching transistors 21 and 22 is D, and the ratio of the number of primary turns to the number of secondary turns of the multi-winding reactor 3 is 1:1. Then, it can be expressed by the following equation (1).

v8= −=−v, −−−−−−−−−−−−−−−
(,t)l-Dn From equation (1), it can be seen that if D<0.5, that is, the switching duty is shifted to less than 50%, the above-mentioned commutation condition v+>Vat is satisfied. Even if the switching duty is set smaller than 50%, a desired voltage can be output by changing n, which is the ratio of the first winding to the second winding of the winding reactor 3. In other words, although it varies depending on the switching duty D, if the number of primary turns is smaller than the number of secondary turns, the output voltage ■ becomes the power supply voltage V,
It is possible to increase the output voltage v8, or conversely, increase the number of primary turns to lower the output voltage v8, so the ringing choke type DC-
The relationship between the input voltage and output voltage of the DO converter can be changed freely.

FIG. 6 is a circuit diagram showing an embodiment of the present invention,
A case where the switching duty exceeds 50% is shown. In FIG. 6, a DC power supply 1, a wiring inductance 2, a wire-wound reactor 3, a rectifier diode 6, a smoothing capacitor 8, a DC load 9, a positive transistor switch 21, a negative transistor switch 22, a negative diode 23, a positive The reference numerals assigned to the side diodes 24 and their names, uses, and functions are completely the same as those in the embodiment shown in FIG. 4, so their explanations will be omitted. Even if the switching duty is made smaller than 50%, the Do-
As already mentioned, it is possible to freely determine the relationship between the input voltage and output voltage of the 'Do converter7, but if you want to obtain a high voltage by increasing the switching duty to 50% or more due to unavoidable circumstances. As shown in FIG. 6, an auxiliary energy recovery means 26 is inserted between the positive side diode 24 and the positive electrode of the DC power supply 1, so that the upper power supply voltage appears to be higher. Prevents energy from being diverted to the load side.

The energy recovered by the energy recovery means 26 is returned to the DC power supply 1 by the energy return means 28 to improve the efficiency of the converter. Clamp capacitor 15 and Do-D in the conventional example shown in FIG.

This can be realized by using the converter 16 or the like.

(Effects of the Invention) According to the present invention, semiconductor switches are provided on the positive and negative sides of the blown winding of the transformer 1 connected to the DC power supply of the DC-DC converter, and the voltage accumulated in the inductance is This simple circuit configuration connects diodes on both sides of the inductance with polarity that allows energy stored in wiring inductance or leakage inductance of a transformer to be returned to the power supply. Since the above energy can be recovered to the power source, the efficiency of the D0-'Do converter can be greatly improved. Especially D
As the capacity of the O-DC converter increases, its current also increases, but the energy that is accumulated in leakage inductance, wiring inductance, etc. and does not contribute to voltage conversion rapidly increases in proportion to the square of the current. . Thunder again,
As the current increases, the wiring also becomes thicker, and it is also a problem to reduce the inductance by twisting the wiring together.
The larger the capacity of the DC-DCC compal, the more energy is recovered by the present invention, and the effect of improving efficiency is significant.This energy recovery and return circuit to the power source is extremely simple and low cost compared to the conventional method. Becomes the property of

When it is necessary to increase the switching duty to 50% or more, for example, capacitors and Do-Do converters are required for energy recovery and return, but these capacitances can also be smaller than conventional ones. Therefore, costs can be reduced.

[Brief explanation of drawings]

Figure 1 shows the conventional ringing choke type II O-D C.
Converter circuit diagram: FIG. 2 is a current/voltage waveform diagram of each part in the circuit shown in FIG. 1, and FIG. 3 is also a circuit diagram of a conventional ringing choke type Do'-LDO converter. FIG. 4 is a circuit diagram showing an embodiment of the present invention, and FIG. 5 is a current/voltage waveform diagram of each part in the embodiment shown in FIG.
FIG. 6 is a circuit diagram showing a second embodiment of the present invention. 1: DC power supply, 2: Wiring inductance, 3: Compound winding reactor, 4: Reactor, 5: Transistor switch, 6: Rectifier diode, 8: Smoothing capacitor, 11: Clamp diode, 12゜26 = Energy recovery means,
13.28: Energy return means, 15: Clamp capacitor, 16: Do-Do converter, 21: Positive side transistor switch, 22: Negative side transistor switch, 23: Negative side diode, 24: Positive side gouoh Figure 1, Figure 2 Figure 3

Claims (1)

[Claims] 1) Energy is injected into the transformer by connecting the primary winding of the transformer to a DC power source via a switch means, and the injected energy is transferred from the secondary winding of the transformer to the rectifier diode by turning off the switch means. In the ringing choke type Do-Do converter, which is connected to the Ichihara power source, the switching means consists of two semiconductor switches inserted into both terminal sides of the Ichihara power supply and controlled to turn on and off at the same time. Each transformer primary winding side terminal is connected to the corresponding terminal of the DC power supply directly or through an auxiliary energy recovery circuit through a diode, respectively, in order to recover the energy accumulated in the transformer leakage inductance when the semiconductor is off. A Do-Do converter characterized by: