JPS5831616B2 - Multi-shunt voltage regulator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a constant voltage device using a shunt regulator.

In general, power sources such as solar cells and fuel cells have the voltage-current characteristics shown in Figure 1. In order to configure a constant voltage device using these as power sources, the output voltage 1 must be set as shown in Figure 2. A shunt regulator that is detected by a voltage detection circuit 4, controls the impedance of a shunt circuit 3 using this detection signal, and controls the output voltage 1 to a constant value by a feedback circuit that shunts the current of the power source 2 to the shunt circuit 3. is used.

That is, the difference between the current generated by the power source 2 at the desired output voltage 1 and the current supplied to the load 5 is transferred to the shunt circuit 3.
In this method, the output voltage 1 is controlled to a constant value by dividing the current into the output voltage 1.

When the desired output current capacity is larger than the current generated by one power source 2, conventionally a plurality of power sources 2 are connected in parallel via a diode 6 as shown in FIG.
A configuration in which a shunt circuit 3 and a voltage detection circuit 4 are connected has been used.

First, the operation of the apparatus will be explained with reference to FIG.

Although FIG. 3 shows a case where three power sources 2 are connected in parallel for convenience of explanation, there is no particular restriction on the number of parallel power sources.

In FIG. 3, when the characteristics of each power source 2 are shown in FIG. 1, if three power sources 2 are connected in parallel, and the voltage drop across the diode 6 is ignored, the
The voltage-current characteristics shown in FIG. 4 are obtained in which the voltage is one time and the current is three times as shown in the figure.

In Figure 4, if the load current at the desired output voltage ■ is IL, and the output current of the power source connected in parallel is ■, then in order to control the output voltage to ■, the difference current Is between ■ and IL is sent to the shunt circuit. All you have to do is separate the flow.

Specifically, the voltage detection circuit 4 generates an error signal 7 having the characteristics shown in FIG. 5, which amplifies the difference between the output voltage ■ and the target output voltage Vo.
As shown in the figure, the error signal 7 has a characteristic of decreasing as the error signal 7 increases, and as the output voltage 1 increases, the impedance of the shunt circuit 3 decreases, and the current flowing to the shunt circuit 3 increases, resulting in a decrease in the output voltage 1. By configuring a circuit and designing its loop gain to be ten large, the device can be made into a microdevice in which the difference between the output voltage (2) and the target output voltage Vo does not pose a practical problem.

The voltage detection circuit 4 and shunt circuit 3 having such operational functions can be easily realized by electronic circuits using semiconductor elements or the like.

The above is the principle of the constant voltage device shown in FIG.

As an example, in Figure 4, the load current IL is the power source output current
Considering the case where the current is 1/2, the impedance of the shunt circuit 3 is controlled so that the shunt current Is represented by I-IL flows through the shunt circuit 3.

That is, as shown in FIG. 5 fζ, the error signal E generated in response to the output voltage V controls the impedance of the shunt circuit 3 to Rs according to FIG. CD/AD matches Rs and Is is controlled to flow through the shunt circuit 3.

The power consumed by the shunt circuit 3 at this time is expressed by the area surrounded by ABCD in FIG.

However, in this method, when the power consumption of the load 5 is small, the shunt power consumed inside the shunt circuit 3 becomes large, making it difficult to thermally design the shunt circuit 3 and the constant voltage device, and the shunt power is dissipated to the surroundings. The drawback was that it generated a lot of heat.

This invention eliminates the above-mentioned drawbacks of the conventional technology, and as shown in FIG. 7, a shunt circuit 3 is connected to each power source 2,
By sequentially controlling the impedance of each shunt circuit 3 in response to the error signal 7, the output voltage 1 can be controlled to a constant voltage, and the total power consumed by the shunt circuit 3 can be reduced, including the shunt circuit. This facilitates the thermal design of a constant voltage device and reduces the influence of heat radiation to the outside.

Hereinafter, one embodiment of the present invention will be described based on the drawings.

In Fig. 7, 1 is the output voltage, 2 is the power source, 3 is the shunt circuit, 4 is the voltage detection circuit, 5 is the load, 6 is the diode that connects the power source 2 in parallel, and 7 is the error from the desired value of the output voltage 1. is the error signal to detect.

For convenience of explanation, FIG. 7 shows a case where three power sources 2 are connected in parallel, but there is no particular limit to the number of parallel power sources.

In FIG. 7, the operating functions of each part are the same as those described in the explanation of FIG. 3, but instead of the three shunt circuits 3 operating simultaneously, the error signal 7 as shown in FIG.
The difference is that the shunt circuits 3 are designed so that the impedance of the shunt circuits 3 is sufficiently low when the error signal 7 is larger than the operating range of each shunt circuit 3. .

That is, according to the amplification port of the error signal 7, the shunt circuit 3/161' first enters the operating range, and the impedance gradually decreases from a very large value.

At this time, the shunt circuit 3/16.2 and the ivy 3 do not operate, and the impedance is extremely large.

Next, when the error voltage 7 exceeds the operating range of the shunt circuit 3/161, the shunt circuit 342 enters the operating range, and the impedance of the shunt circuit 3/162 gradually decreases from a very large value.The shunt circuit 3 does not operate. .

On the other hand, the impedance of the shunt circuit 3A1 has a sufficiently low value.

In this way, the shunt circuit 3 operates in sequence in response to the error signal 7, and is designed so that when the error signal 7 exceeds the operating range of the shunt circuit 3, the impedance of the shunt circuit 3 becomes sufficiently low. do.

The voltage detection circuit 4 and shunt circuit 3 having such operational functions can also be easily realized by electronic circuits using semiconductor elements or the like.

In FIG. 7, if we consider the case where the load current is 1/2 of the output current of the power source 2 as in FIG. 3, the error signal 7 in FIG. , and its impedance is R8.

Furthermore, since the error signal (E) exceeds the operating range of the shunt circuit 3<1>, the impedance of the shunt circuit 3<1> has a sufficiently low value RT.

Shunt circuit 3. %3 does not operate because the error signal ■E has not reached its operating range, and the impedance is extremely large.

Power source 2A1, A62, /% in this operating state
The operating point of No. 3 is as shown in FIG.

The power source 2/16.1 is short-circuited by the impedance RT of the shunt circuit 3 A1, and the operating point E1 is the shunt current I
It becomes St.

Here, RT is expressed as GH/FG, but if the shunt circuit 3 is designed so that this value is sufficiently low, the output voltage of the power source 2A1 will be the value expressed by H in FIG.
Since the output voltage becomes lower than the output voltage ■, the diode 6 is reverse biased and no current is supplied to the load 5.

In addition, the power source 2/162 is short-circuited by the impedance Rs of the shunt circuit 3/16.2, and ILt, which is 1/2 of the output current of the power source 2A2, is transferred to the load 5, and the remaining IS
2 flows to the shunt circuit 3A62, and the operating point becomes ■.

Here, the impedance Rs of the shunt circuit 3/i62 is expressed as LM/KL.

Further, since the impedance of the shunt circuit 3/163 of the power source 243 is very large, the entire output current IL2 is supplied to the load, and the operating point is φ.

The current supplied to the load as a whole is the sum of ILt and IL2.

When the load current is small due to the condition shown in Figure 9, power source 2 /%1 and /I62 are short-circuited with sufficiently low impedance as shown in Figure 10, and IL3 of the output current of power source 2 /163 is used as the load. The remaining I83 supplied to the shunt circuit 343 flows to the shunt circuit 343.

In addition, if the load current is larger than the state shown in Fig. 9, only the shunt circuit 3/461 enters the operating region as shown in Fig. 11, and IL4 of the current generated by the power source 2/%1 is transferred to the load 5. , IS4 flows to the shunt circuit 3 A1.

Shunt circuit 3/162, A3 does not operate, power source 2
2. All of the output current IL511L6 of the scrap 3 is supplied to the load 5.

As explained above, by sequentially controlling the impedance of each shunt circuit 3 in accordance with the error signal 7, the output voltage 1 is controlled to a constant voltage.

- On the other hand, in Fig. 9, shunt circuit 341, /162
463, the area surrounded by EFGH for shunt circuit 3/161, the area surrounded by KLMN for shunt circuit 3/162, and the area surrounded by KLMN for shunt circuit 3/162. It becomes zero at %3.

These sums are clearly smaller than the shunt power represented by the area ABCD in FIG.

The reason is that the shunt power is reduced because the shunt circuit 3 is designed so that its impedance becomes sufficiently low when the error signal 7 exceeds the operating range of the shunt circuit 3.

In other words, in the operating state of the conventional method shown in FIG. 4, all three power sources 2 are operating at voltage ■, so the shunt power is the area surrounded by PQGR in FIG.
It corresponded to the sum of the areas surrounded by LMN, but in the case of this invention, the area surrounded by PQGR is equivalent to EF
The area surrounded by GH becomes the shunt cooling power, and the shunt power is reduced by the difference between the two.

In the above embodiment, an example was explained in which the power sources 2 are arranged in three parallels, but the power sources 2 can of course be similarly applied to cases in which the power sources 2 are arranged in two parallels, four or more in parallel, and the greater the number of parallels, the greater the effect of reducing shunt power.

As described above, the present invention can greatly reduce the amount of heat generated by the shunt circuit, thereby facilitating the thermal design of the shunt circuit and the constant voltage device including the shunt circuit.

It also has the advantage that there is little effect of heat radiation on devices placed around the constant voltage device, and is particularly useful in high-density packaging machines such as aircraft and artificial satellites.

A further secondary effect is that the reliability of the constant voltage device is improved because a plurality of shunt circuits are provided.

[Brief explanation of the drawing]

Figure 1 is a voltage-current characteristic diagram of the power source, and Figure 2 is a shunt/current characteristic diagram.
Fig. 3 is a block diagram of a conventional shunt regulator; Fig. 4 shows the operation of the power source in the conventional shunt regulator shown in Fig. 3; Fig. 5 shows the characteristics of the voltage detection circuit; Figure 6 shows the characteristics of the shunt circuit.
Fig. 7 is a block diagram of the shunt regulator of the present invention, Fig. 8 is the characteristic of the shunt circuit shown in Fig. 7, and Fig. 9 is a block diagram of the shunt regulator of the present invention.
Figures a, b, c1 Figure 10 a t b t C% Figure 11 a, b. C is a diagram showing the operation of each power source in FIG. 7. In the figure, 1 is the output voltage, 2 is the power source, 3 is the shunt circuit, 4 is the voltage detection circuit, 6 is the load, 6 is the diode for connecting the power sources in parallel, and 7 is the error signal that controls the shunt circuit. . Note that the same reference numerals are given to the same or equivalent parts in FIG.

Claims (1)

[Claims] 1 A device that connects multiple power sources in parallel and controls their output to a constant voltage.In this device, multiple sets of shunt circuits are connected to the power sources in parallel, and a diode is connected in series to each set. The region where the impedance of the shunt circuit is controlled corresponds to the output voltage of the power sources connected via diodes (the range of electric power in the same lesson)
Within that voltage range, the impedance of the shunt circuit is controlled from a large value to a small value according to the output voltage, and the impedance of one specific shunt circuit is controlled in response to the state of the power source and load. In this case, the impedances of other shunt circuits corresponding to output voltages whose controlled area is higher than that of the shunt circuit are all sufficiently large, and almost all of the output power of the power source is supplied to the load and is consumed in the shunt circuit. The output voltage of the power source is made sufficiently low by making the impedance of all the shunt circuits corresponding to the low output voltage sufficiently low, and short-circuiting the power source with that impedance. By sequentially controlling the impedance of the shunt circuit according to the output voltage so that the shunt power, which is expressed as the product of the output current and is consumed in the shunt circuit, is sufficiently small, the output voltage can be kept at a nearly constant voltage. A multi-shunt voltage regulator characterized in that the total power consumed in the above-mentioned shut-off circuit is reduced by controlling.