JPH02206362A - Switching mode-type power converter apparatus - Google Patents

Abstract

PURPOSE:To miniaturize parts to be used and to prevent damage and unstable action such as hunting by capacitor-dividing a DC input voltage, by giving a 180 deg. phase difference to a switching period and by parallel-connecting the output side. CONSTITUTION:The main transformer T1 of a DC-to-DC converter I is provided with a tertiary winding n1-3 and connected in such manner that a capacitor C2 on the input side os a DC-to-DC converter II is charged with a electricity through a rectifying device D01 and an inductance L0 by a generated voltage from the tertiary winding. Likewise, the circuit II is also connected so that C1 is charged with electricity by the generated voltage from the tertiary winding n2-3 of the T1. If the voltage of the C1 lowers, the voltage of the C2 rises as much and a voltage is induced in the tertiary winding n2-3 of the T2 at the ON time of switching elements Q3, Q4 in the manner of corresponding to the voltage of the C2 to charge the C1 with electricity to improve an unbalanced state into a balanced state.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a switching mode power converter.

Conventionally, in switching mode power converters with relatively high DC input voltage, the DC input voltage is divided,
A circuit system is known in which a DC-to-DC converter circuit is connected to each of the divided voltages as a t source, and both section λ-interval converter circuits are simultaneously controlled in switching and connected in parallel on the output side. In the first part, a circuit example of a conventional switching mode power conversion device is shown.

■, ■ are DC to DC conversion circuits, A%B is switch control section, T
1. T2 is the main transformer, Dt%D2, Dl, D are rectifying elements, L, L, LJ are inductances, 01%C3
, C3 is a capacitor, RE is! 1 current circuit, AC is alternating current input, DC is direct current = power. If the output voltage of the rectifier circuit RE reaches 1350V, for example, there will be restrictions on the ratings of the parts used, so it is divided into two by capacitors C and C2, and each is used as a t source.ai! Connect f-to-f conversion circuits I and n. I
The switch controllers A and B of J and ] are simultaneously turned on and off to generate output voltages VI and VH of J and ] as shown in the voltage waveform diagram of FIG. The output sides of I and T are connected in parallel, and the output voltage vTEo is the 23rd! Like J.
V I , , and VH6 are combined to provide the tL output DC. Thus, 1. The conventional device that performs output A adjustment by controlling the pulse width using the H circuit achieves the purpose of reducing the ratings of the parts used, but 1. ':l are smoothed by the respective circuits and then combined, so as to be described later,
It is not possible to downsize the components used in the output filter circuit.

The present invention eliminates the drawbacks of the conventional device mentioned above, and by increasing the frequency of the output filter circuit, the parts used are made smaller, and the unbalance of the capacitor voltage that is likely to occur due to death and division is eliminated, and damage to the used parts, hunting, etc. This is intended to prevent unstable operation.

Next, the present invention will be explained with reference to the drawings. FIG. 3 is a circuit diagram of a switching mode power conversion device showing an embodiment of the present invention, and the same reference numerals as in FIG. 1 indicate portions. The switch control section of the DC-to-DC conversion circuit consisting of switch elements Q1, Q2, etc. and the n-minute switch control section of the DC-DC conversion circuit consisting of switch elements Q, , Q, etc. are mutually controlled by a control signal circuit (not shown). 1806 to turn it on and off. As a result, the output voltage VI of one circuit (2) and the output voltage (2) of circuit (2) are connected in parallel, resulting in an output voltage of <,vm as shown in FIG. Therefore, if the conversion frequencies of the conversion circuits in Section 1 and FIG. 3 are the same, compared to VI or ■ in FIG. 2,
In the fourth section VIII, the frequency applied to the output filter circuit is doubled, and the output filters L4 and CI can be made smaller.

First, the DC input voltage is divided by a capacitor, circuits ■ and circuits are connected, and the switching period of these conversion circuits is
The above object is achieved by providing a phase difference of 80° and by connecting the output sides of circuit I and circuit (2) in parallel. However, when controlling the pulse width of the output voltage by alternately applying the same control signal with a 180" phase difference to the circuits (2) and (2), some problems may occur due to some reasons, such as transient operation or variations in the conversion circuit. If an imbalance occurs between the voltages of capacitors C1 and 02, for example, the voltage of CI becomes small, and the voltage V of the fourth capacitor becomes
1), and the output voltage V■ is controlled at a predetermined average value, so between Vl and ■■ and between C1 and C2
No action is taken to correct the respective imbalance between the voltages. If the voltage imbalance is large, the voltage may cause damage to the used components due to excess voltage resistance, or unstable operation such as hunting.

A further improved additional circuit of the present invention that prevents the occurrence of the imbalance described above is shown in FIG. Rectifier element. , and inductance L
. is connected to charge the capacitor C2 on the input side of the lfL flow 1 conversion circuit H through the lfL current 1 conversion circuit H.

Similarly, for circuit H, the tertiary winding N2 of T1. ．． ．． C1 is connected so as to be charged by the generated voltage.

The voltage across C2 rises, and in response to the voltage across C2, the tertiary winding N2-6l of T2 turns on when the switching elements Q and Q are turned on.
A voltage is induced in C1, which charges C1. That is, by charging the lower capacitor with a voltage corresponding to the higher capacitor voltage, the unbalanced state of vm(i) in FIG. 4 is improved to a balanced state as shown in VIII(ii). Note that since the voltages of the main transformers T1 and T2 are rectangular waves, La is an inductance for suppressing rush current when voltage is applied, and is also a rectifier element. 2,
D, . . . form a current circulation circuit with an inductance L0 when the outputs of the main transformers T1 and T2 are turned off. According to experiments, in the circuit of FIG. 3, AC input is 480 V, DC voltage of rectifier circuit RE is 644 V (sum of voltages of C and C2), and main transformer T1. If the primary winding of T is 36 turns, the tertiary winding is 35 turns, and L is 150 μH, then 2 CI
The voltage on C2 was 325 cm, and the voltage on C2 was 3i9V, which was a difference of 6 cm. In comparison, N 1-01. A difference of 2.5 V occurred in the case without an additional circuit such as a tertiary winding of N 2'-+t. Note that in order to obtain a voltage corresponding to the input voltage, it is not necessarily necessary to use the tertiary winding, but other means such as taking out the voltage from the primary winding with a tap may also be used.

In FIG. 3, the AC input is rectified by the rectifier circuit RE to obtain the DC input, but it goes without saying that the present invention can also be applied to cases where the DC input is directly obtained from the battery. The DC-to-DC converter circuit and the switch element (■) are not limited to transistors,
Furthermore, various known circuit systems can be applied. Furthermore,
Any additions, deletions, or changes made to the circuit are within the scope of the gist of the present invention and are included in the rights of the present invention.

As described above, by implementing the present invention, it is possible to reduce the size of used parts, balance the divided voltages, stabilize the operation, etc. in a power conversion device with a relatively high DC input voltage.
It can be used in various power sources, including communication power sources, and the effect is extremely large.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram of a conventional device, Fig. 2 is a voltage waveform diagram of a conventional device, Fig. 3 is a circuit diagram showing an embodiment of the present invention, and Fig. 4 is a voltage waveform diagram of Fig. 3. , ■ is a DC-to-DC conversion circuit,
A and B are switch control units, T1 and T2 are main transformers, D,
,D,,D,,,D4,Dot,I)o2,D oJ,
D o4 is a rectifying element, L,, L, L,, L, 1%L1
, is the inductance, C1, C7, C, l are the capacitors, N l-I N 2-1 is the primary winding, N1-1, N
z-8 is a tertiary winding, Q, Q2, Q3, Q are switch elements, RE is a rectifier circuit, AC is an alternating current input, DC is a direct current output, VI, VI, , vm, VIIo
, V■, ■mo are the voltages shown, respectively.

Claims (3)

[Claims] (1) The DC voltage is divided by a capacitor, each capacitor is connected to the input side of a DC-to-DC conversion circuit, and the output sides of both conversion circuits are connected in parallel, and each output of both conversion circuits is A switching mode power converter characterized in that a voltage has a phase difference of 180°. (2) The switching mode type according to claim (1), which is configured to charge a capacitor supplying a lower input voltage with a voltage corresponding to a higher input voltage in the DC-to-DC conversion circuit. Power converter. (3) The switching according to claim (2), in which the main transformers of the two DC-to-DC conversion circuits are each provided with a tertiary winding, and the output sides of the tertiary windings are connected to the capacitors on the other side. Mode type power converter.