JPH09135529A - Dc power supply system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify a connecting means and prevent a short-circuiting fault when connecting a DC power unit to a load equipment. SOLUTION: This system supplies the DC output of a DC power unit 1 to a load equipment consisting of a storage battery 8 and a load 9. The DC power unit 1 is constituted of a polarity switching circuit 3 which consists of a plurality of switches S1-S4 for switching the output polarity of a power converting section 2 and a polarity detecting circuit 4 which detects the output polarity of the DC power unit 1. The switches S1-S4 of the polarity switching circuit 3 are operated on polarity detection signals of the polarity detecting circuit 4.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a DC power supply device,
The present invention relates to a DC power supply system that prevents a short circuit accident when connecting a load device including a storage battery and a load.

[0002]

2. Description of the Related Art An example of the prior art is shown in FIG. The conventional DC power supply system includes a load device 7'in which a storage battery 8'and a load 9'are connected in parallel, and a DC power supply device 1'having a power conversion unit 2'and an output unit 16 for supplying DC power. Become. When connecting the load device 7'to the DC power supply device 1 ',
The output terminal A of the power converter 2'is the positive terminal 11 'and B
Is the negative terminal 13 ', the terminal A'of the output unit 16 and the terminal A'which is the positive terminal 12' of the load device 7 ', and the terminal B'of the output unit 16 and the negative terminal 14' of the load device 7 '.
When the terminal B ″ is connected by the output line 10 ′, it is normally connected, and therefore the polarity detection circuit 4 ′ includes the output switch 15 of the output unit 16 which supplies the output of the power conversion unit 2 ′.
To supply the output. On the other hand, when the terminal A ′ of the output unit 16 and the terminal B ″ of the load device 7 ′ and the terminal B ′ of the output unit 16 and the terminal A ″ of the load device 7 ′ are connected, the terminals are connected to different polarities. Therefore, the polarity detection circuit 4'acts so as not to turn on the connection switch 15 of the output section 16 so as not to supply the output of the power conversion section 2'to the load device 7 ', thereby preventing a short circuit. There is.

[0003]

In the prior art, when the DC power supply device and the load device are connected, if the polarities are mistakenly connected in the opposite direction, the polarity detection circuit detects this and a short-circuit accident does not occur. No, but in this case the maintenance person is positive,
It was necessary to reverse the polarity by changing the connection of the negative output line. Generally, the terminals of the DC power supply device and the terminals of the output lines of the load device are fastened to each other by bolts, which requires labor to replace the wiring. Further, the space between the positive electrode and the negative electrode has become narrower as the device has been downsized, and there has been a risk of a short circuit accident or the like due to wiring change.

The present invention has been made in view of the above circumstances, and provides a DC power supply system capable of simplifying the connecting means and preventing a short-circuit accident when connecting a DC power supply device and a load device. The purpose is to

[0005]

In order to achieve the above object, the present invention comprises a polarity switching circuit composed of a semiconductor switch for switching the output polarity at an output portion of a DC power supply device,
When a load device composed of a storage battery and a load is connected, the polarity is detected by the polarity detection circuit that determines the output polarity of the DC power supply device, and the semiconductor switch of the polarity switching circuit is operated to output the output. The feature is that the polarity of the terminals is properly connected and the output can be turned on without changing the wiring of the output line once connected. The difference is that the output could not be supplied unless replaced.

According to the present invention, when the DC power supply device is connected to the load device, it is possible to normalize the polarity by detecting the polarity of the output terminal of the DC power supply device. It is possible to turn on the output of the DC power supply device so as not to cause a short-circuit accident even at the time of connection, simplify the connecting means, and prevent a short-circuit accident.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows an embodiment of the present invention. The DC power supply device 1 includes a power conversion unit 2 having a positive electrode terminal 11 and a negative electrode terminal 13, a polarity switching circuit 3 having switches S1, S2, S3, S4 for switching the output polarity of the power conversion unit 2, and the DC power supply device 1 A polarity detection circuit 4 for detecting the polarity of the output terminal of is provided, and the signal of this polarity detection circuit 4 is input to the control circuit 5. Power is supplied to the polarity detection circuit 4 and the control circuit 5 by the storage battery 8 and the load 9.
Is supplied from the load device 7 and is supplied through the diode block 6 so as to be normally supplied regardless of whether the polarity is normal or abnormal. In the figure, 10 is an output line, 12
Is a positive terminal of the load device 7, 14 is a negative terminal of the load device 7, and D is a reverse current prevention diode. That is, the switch S1, which is set on the output part of the DC power supply device 1,
S2, S3, S4 are provided, the DC power supply device 1 and the load device 7
It is possible to cancel the connection error with the switch by turning on / off the switches S1, S2, S3 and S4.
The control circuit 5 is a circuit for controlling the output of the power conversion unit 2 and is not an essential component of the present invention.

Next, the operation of the embodiment of the present invention will be described in detail. When the load device 7 is not connected to the DC power supply device 1, the control circuit 5 does not operate and there is no input signal.
S4, S2, and S3 always maintain the off state. The switches S1 to S4 of the polarity switching circuit 3 are controlled by the ON signal of the control circuit 5. A of the power conversion unit 2
Is a positive electrode terminal 11, B is a negative electrode terminal 13, and A ″ of the load device 7 is a positive electrode terminal 12 and B ″ is a negative electrode terminal 14. The output terminals A'and B'of the polarity switching circuit 3 can be either positive or negative depending on the polarity of the connected load device 7.

By connecting the DC power supply device 1 and the load device 7, the DC power from the storage battery 8 of the load device 7 is supplied to the polarity detection circuit 4 and the control circuit 5 via the diode block 6. In this case, regardless of the polarity of the load device 7 connected to the output terminals A ′ and B ′ of the DC power supply device 1, the diode block 6 rectifies and stabilizes and supplies it to the polarity detection circuit 4 and the control circuit 5. This enables control of the power conversion unit 2 and operation of the polarity switching circuit 3. Here, when the output terminals of the DC power supply device 1, that is, the output terminals A ′ and B ′ of the polarity switching circuit 3 are connected to the positive electrode terminal A ″ and the negative electrode terminal B ″ of the load device 7, respectively, the connected terminals are The polarity detection circuit 4 detects the polarity,
The switches S1 and S1 of the polarity switching circuit 3 are arranged so that the terminals A and B of the power converter 2 of the DC power supply device 1 and the terminals A ″ and B ″ of the load device 7 are connected to each other.
A signal for turning on S3 is sent from the polarity detection circuit 4 to the polarity switching circuit 3, and the switches S1 and S3 are turned on by this signal. By turning on the switches S1 and S3 of the polarity switching circuit 3 and turning off the switches S2 and S4, the positive terminal A of the power converter 2 is connected to the output terminal A ′ of the polarity switching circuit 3 and the load device via the switch S1. 7 is connected to the output terminal A ″ of the power converter 2, and the negative terminal B of the power converter 2 is connected to the output terminal B ′ of the polarity switching circuit 3 and the negative terminal B ″ of the load device 7 via the switch S3. Therefore, since the polarities of the terminals of the power conversion unit 2 and the load device 7 are the same, when the output of the power conversion unit 2 is established, the power can be stably supplied to the load device 7 via the polarity switching circuit 3.

A concrete example of the operation of the polarity detection circuit 4 using a photo coupler is shown in FIG. When the output terminals A ′ and B ′ of the polarity switching circuit 3 are connected to the positive terminal A ″ and the negative terminal B ″ of the load device 7, respectively, the polarity detection circuit 4
Is supplied through the diode block 6, and the polarity detection input Vo is input from terminals A'and B ',
Since A'is a positive electrode and B'is a negative electrode, the photocoupler 100 having the diode on the forward side operates. The switch 300 operates by the operation of the photocoupler 100 and sends a closing signal to the switches S1 and S3 of the polarity switching circuit 3.
Since the diode of the photocoupler 200 is reverse biased, the switch 400 does not operate, and the closing signal is not sent to the switches S2 and S4 of the polarity switching circuit 3.

On the other hand, when the output terminals A'and B'of the polarity switching circuit 3 shown in FIG. 1 are connected to the terminals B "and A" of the load device 7, respectively, in the opposite manner, the polarity switching circuit 3's The output terminal A'is a negative electrode and B'is a positive electrode. In this case, the photocoupler 200 of the polarity detection circuit 4 shown in FIG.
Is operated to send a signal for turning on the switches S2 and S4, and thereby the positive terminal A of the power conversion unit 2 and
The terminal B ′ of the polarity switching circuit 3 and the positive terminal A ″ of the load device 7 are connected by a switch S2, and the negative terminal B of the power conversion unit 2, the terminal A ′ of the polarity switching circuit 3 and the negative terminal B of the load device 7 are connected. ″ Are connected by a switch S4. Therefore, the polarities of the output terminals of the power converter 2 and the load device 7 are made the same to prevent a short circuit, and the output of the power converter 2 is stably supplied to the load device 7 via the switches S2 and S4.

FIG. 3 shows the operating states of the switches S1 to S4 of the polarity switching circuit 3 depending on the polarity of the input Vo of the polarity detection circuit 4 described above. When the output terminals A ′ and B ′ of the polarity switching circuit 3 are connected to the positive terminal A ″ and the negative terminal B ″ of the load device 7, respectively, that is, the potential of the output terminal A ′ of the detection voltage Vo of the polarity detection circuit 4 is If it is higher, the switches S1 and S3 are turned on and the switches S2 and S4 are kept off by the operation of the polarity detection circuit 4 described above. On the contrary, when the output terminals A ′ and B ′ of the polarity switching circuit 3 are connected to the negative terminal B ″ and the positive terminal A ″ of the load device 7, respectively, the output terminal B ′ of the detection voltage Vo of the polarity detection circuit 4 is changed. The potential becomes high, the switches S2 and S4 are turned on, and the switches S1 and S3 are maintained in the off state.

As described above, even if the polarities of the output terminals of the load device 7 are connected to the output terminals of the DC power supply device 1 in the opposite manner, the positive polarity of the power conversion section 2 can be obtained by the operation of the polarity detection circuit 4 and the polarity switching circuit 3. The terminal A and the negative electrode terminal B are normally connected to the positive electrode terminal A ″ and the negative electrode terminal B ″ of the load device 7 to prevent a short circuit, and can supply the output of the power conversion unit 2 to the load device 7.

The polarity detection circuit 4 shown in FIG.
Although the circuit using 00 and 200 has been described, a diode and a relay may be used instead of the photocouplers 100 and 200, and the switches 300 and 400 may be formed using semiconductor switches. The switches S1 to S4 used in the polarity switching circuit 3 are preferably semiconductor switches, but may be switches such as relays that can be turned on and off by the detection signal of the polarity detection circuit 4.

[0015]

As described above, in the DC power supply system according to the present invention, when a load device is erroneously connected to the output terminal of the DC power supply device, the polarities can be changed to prevent a short circuit and output normally. It is possible to connect to a load device consisting of a storage battery and a load without checking the polarity of the DC power supply device. Also, when a plurality of DC power supply devices are connected in parallel and supplied to the load device, the polarity is similarly switched to enable safe and easy power supply. Furthermore, since much labor required for wiring change can be eliminated, it is particularly effective in an emergency.

[Brief description of the drawings]

FIG. 1 is a configuration explanatory diagram showing an embodiment of the present invention.

FIG. 2 is a circuit diagram showing an example of a polarity detection circuit of FIG.

FIG. 3 is an explanatory diagram showing an example of a switch operation of the polarity switching circuit of FIG.

FIG. 4 is a configuration explanatory view showing a connection between a conventional DC power supply device and a load device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... DC power supply device, 2 ... Power converter part, 3 ... Polarity switching circuit, 4 ... Polarity detection circuit, 5 ... Control circuit, 6 ... Diode block, 7 ... Load device, 8 ... Storage battery, 9 ... Load, 10
Output lines, 11, 12 ... Positive terminal, 13, 14 ... Negative terminal, 15 ... Output switch, 16 ... Output section, 100 ... Photo coupler, 200 ... Photo coupler, 300 ... Switch,
400 ... switch.

Claims (1)

[Claims] 1. A direct current power supply system for supplying a direct current output of a direct current power supply device to a load device comprising a storage battery and a load, wherein the direct current power supply device comprises a power conversion unit and a plurality of switches for switching output polarities of the power conversion unit. And a polarity detection circuit for detecting the output polarity of the DC power supply device, and a switch of the polarity switching circuit is operated by a polarity detection signal of the polarity detection circuit. system.