JPH1141913A - Power circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power circuit with good efficiency, in which loss in power is drastically reduced by passing only a variation control factor through a power conversion circuit, and reducing the power to be converted. SOLUTION: When a voltage higher than a voltage of a power supply 1 is fed to a load, an output from a positive terminal Pa of a power conversion circuit 2 is negatively fed back to obtain a target voltage. A negative terminal Pb of a power conversion circuit 2 is connected to a positive terminal of the power supply 1, and these terminals have the same potential. Then, a short voltage with respect to the power voltage is generated by the power conversion circuit 2, and the total amount of voltages is fed to a load 3 (step A). When a voltage lower than the power supply voltage is fed, the feeding voltage from the power conversion circuit 2 to the load 3 is fed back negatively to obtain a target voltage, and the output terminals of the power conversion circuit 2 are connected to terminals with each polarity in the power supply (step B). A lower voltage portion with respect to the power supply voltage is generated by the power conversion circuit 2 and is fed to the load 3. Then, the power obtained by reducing the voltage is fed back to the power supply, and thereby a loss in power is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply circuit applicable to solar illumination, solar light, and other devices using a DC power supply.

[0002]

2. Description of the Related Art Conventionally, a power conversion circuit has been designed so that a conversion circuit is connected in parallel with a power supply and an output is directly connected to a load. An example is shown in FIG. In the figure,
1 is a DC power supply such as a battery, 2 is a power conversion circuit, 3 is a load, and the load 3 is supplied with power from a positive terminal Pa and a negative terminal Pb of the power conversion circuit 2.

A typical power conversion circuit 2 is shown in FIG.
In the figure, 4 is a capacitor as a DC source, 5 is a switching control circuit such as PWM control, 6 is a switching element, 7 is a primary side coupling coil,
8 is a secondary side coupling coil, 9 is a rectifier diode, and 10 is a smoothing capacitor.

[0004] A pulse current corresponding to the switching cycle of the switching control circuit 5 flows through the coupling coils 7 and 8, is rectified to DC by the rectifier diode 9, and a predetermined voltage is accumulated in the smoothing capacitor 10 so that the load of the load is reduced. Power supply. Here, only an example is illustrated as the power conversion circuit 2, and it is a matter of course that other power conversion circuits may be used.

In this conventional power supply circuit, a power conversion circuit 2
The output of the positive terminal Pa is negatively fed back to obtain a desired target voltage. However, the power passing through the power conversion circuit 2 is 100% of the power supplied to the load, and all the power is converted. Therefore, there is a disadvantage that the loss becomes large. That is, the power conversion circuit 2 generally has an efficiency of about 70 to 90%, and a power loss of about 10 to 40% of the supplied power is generated.

[0006]

SUMMARY OF THE INVENTION Therefore, according to the present invention, it is not necessary to convert all the power supplied to the load by making the power passing through the power conversion circuit only the control fluctuation, and the loss is greatly reduced. It is an object of the present invention to provide an efficient power supply circuit.

[0007]

According to a first aspect of the present invention, a power supply circuit includes a power conversion circuit connected in parallel to a DC power supply,
This is achieved by employing a configuration in which the power passing through the power conversion circuit is only the control fluctuation.

In this way, it is not necessary to convert all the power supplied to the load, and an efficient power supply circuit capable of greatly reducing the loss can be obtained.

A power supply circuit according to a second aspect of the present invention is achieved by connecting an input circuit of a power conversion circuit to a DC power supply in parallel and connecting the output circuit and the power supply in series. .

[0010] In this way, a power supply circuit generates a voltage that is insufficient for the power supply voltage, and supplies a voltage obtained by summing up the power supply voltage to the load. That is, since the power passing through the power conversion circuit 2 is lower than the power supplied to the load, the loss can be reduced.

A power supply circuit according to a third aspect of the present invention is achieved by a configuration in which an output circuit of a power conversion circuit is connected in parallel to a DC power supply, and an input circuit is connected in series to the power supply.

In this manner, a loss can be reduced by producing a voltage lower than the power supply voltage by the power conversion circuit and supplying the power to the load, and feeding back the power of the reduced voltage to the power supply.

[0013]

FIG. 1 shows an embodiment of a power supply circuit according to the present invention.
A description will be given with reference to FIGS. 1, the same members as those in FIG. 2 (A) are denoted by the same reference numerals. As the power conversion circuit 2, as in the prior art, FIG.
The following applies.

FIG. 1A shows a case where a voltage higher than the voltage of the power supply 1 is supplied to the load. Although the output of the positive terminal Pa of the power conversion circuit 2 is negatively fed back to obtain a desired target voltage, this is the same as the conventional power supply circuit of FIG. And the positive terminal of the power supply 1 are connected to have the same potential. That is, the input circuit of the power conversion circuit 2 is connected to the DC power supply 1 in parallel,
The output circuit and the power supply are connected in series.

As a result, the power conversion circuit 2 generates an insufficient voltage of the power supply voltage, and supplies the load 3 with the total voltage of the power supply voltage. That is, the power passing through the power conversion circuit 2 is equal to the power supplied to the load (the supply voltage V _L to the load).
−power supply voltage V _P ) / supply voltage V _L to the load * 100 (%)
As a result, the loss can be reduced.

[0016] For example, the power supply voltage V _P 5 v, if 10v supply voltage V _L to the load, the power passing through the power conversion circuit 2 is 50%. Assuming that the power conversion circuit is manufactured with the same technology as the conventional device, the loss is reduced by half,
Efficiency rises to 85-95% and losses can be significantly reduced to 5-18% of supply power.

Next, the case where a voltage lower than the voltage of the power supply 1 is supplied to the load will be described with reference to FIG. 2A is the same as the conventional power supply circuit of FIG. 2A in that a desired target voltage is obtained by negatively feeding back the supply voltage from the power conversion circuit 2 to the load 3. The same polarity is connected such that the positive output terminal Pa is connected to the positive terminal of the power supply 1, the negative output terminal Pb of the power conversion circuit 2 is connected to the negative terminal of the power supply 1, and so on. That is, the output circuit of the power conversion circuit 2 is connected to the DC power supply 1 in parallel, and the input circuit is connected to the power supply in series.

As a result, a voltage lower than the power supply voltage is generated by the power conversion circuit 2 and supplied to the load 3, and the power of the reduced voltage is fed back to the power supply 1 to reduce the loss. That is, the power passing through the power conversion circuit 2 decreases as (power supply voltage V _P −supply voltage _VL to the load) / supply voltage _VL * 100 (%) of the power supplied to the load. Therefore, the loss can be reduced. For example, if the supply voltage of the voltage difference between the difference of about 10% with respect to the power supply voltage V _P, the power passing through the power conversion circuit 2 1/1
0, the loss is also approximately 1/10, and the loss can be greatly reduced.

[0019]

As described above, according to the power supply circuit of the present invention, when a voltage higher than the voltage of the power supply is supplied to the load,
The power conversion circuit generates the voltage that is insufficient for the power supply voltage, and supplies the voltage that is the sum of the power supply voltage and the load to the load. it can.

When a voltage lower than the voltage of the power supply is supplied to the load, a voltage lower than the power supply voltage is generated by the power conversion circuit and supplied to the load, and the reduced power is fed back to the power supply. As a result, the loss can be reduced. Further, according to the present invention, it is not necessary to convert all the power supplied to the load, and it is possible to obtain an efficient power supply circuit capable of greatly reducing the loss.

[Brief description of the drawings]

FIG. 1 is a block diagram of a power supply circuit of the present invention.

FIG. 2 is a block diagram of a conventional power supply circuit.

[Explanation of symbols]

 Reference Signs List 1 DC power supply 2 Power conversion circuit 3 Load 4 Power supply capacitor 5 Switching control circuit 6 Switching element 7 Primary coupling coil 8 Secondary coupling coil 9 Rectifier diode 10 Smoothing capacitor

Claims (3)

[Claims] 1. A power supply circuit, wherein a power conversion circuit is connected in parallel to a DC power supply, and power passing through the power conversion circuit is limited to control fluctuations. 2. A power supply circuit in which an input circuit of a power conversion circuit is connected in parallel to a DC power supply, and the output circuit and the power supply are connected in series. 3. A power supply circuit in which an output circuit of a power conversion circuit is connected in parallel to a DC power supply, and an input circuit is connected in series with the power supply.