JPH0549163A - Dc power supply - Google Patents

Abstract

PURPOSE:To provide a highly reliable DC power supply in which terminal voltage of a load can be maintained constant by compensating for the voltage drop between the power supply and the load. CONSTITUTION:The DC power supply comprises a gate controller 5 for controlling the output voltage of a rectifier 2 to nullify the difference between the output voltage of the rectifier 2 and a preset reference voltage and a voltage drop compensator 6 for calculating a voltage drop by multiplying the output of the gate controller 5 by a preset resistance of a cable 7 and delivering a correcting voltage signal to the gate controller 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a DC power supply device.

[0002]

2. Description of the Related Art Generally, in FIG.
It consists of a transformer 1, a rectifier 2 for converting alternating current to direct current and a battery 3. The rectifier 2 supplies a minute charging current to the battery 3 and also supplies DC power to the load 4 via the cable 7. Therefore, the output voltage of the rectifier 2 is the gate control device 5
Thus, the battery 3 is kept at a value suitable for charging. That is, the output voltage of the rectifier 2 is kept at a certain value regardless of the load current and the terminal voltage of the load 4, while the terminal voltage of the load 4 is obtained by subtracting the voltage drop of the circuit from the output voltage of the rectifier 2. It becomes a value.

[0003]

As described above, the conventional DC power supply device has the following problems because the output voltage is controlled to be constant regardless of the load 4. (1) Since it is necessary to suppress the voltage drop between the DC power supply device and the load 4 within an allowable value, a very large size cable 7 must be used.

(2) Systems with relatively close voltage (24V, 48
In V), the voltage drop cannot be suppressed within the allowable value by simply increasing the size of the cable 7, and the length of the cable 7 is reduced. Therefore, the distance between the DC power supply device and the load must be sufficiently short. I have to. (3) In the case of the above (2), those conditions must be taken into consideration before determining the arrangement plan of each device, but it is difficult in reality.

The present invention has been made in view of the above problems, and an object of the present invention is to detect a load current or a terminal voltage of the load and change the output voltage of the rectifier according to the magnitude of the detected voltage to change the voltage. Another object of the present invention is to provide a DC power supply device that compensates for the amount of drop and solves the above problems.

[0006]

To achieve the above object, a DC power supply device of the present invention comprises a rectifier connected to a transformer to supply a minute charging current to a battery and DC power to a load via a cable. A gate controller for detecting the load current or the terminal voltage of the load and controlling the output of the rectifier so that the difference between the output signal of the rectifier and the reference signal becomes zero, and a voltage drop component based on the cable in the gate controller. And a voltage drop compensating device for giving a correction signal to

[0007]

The present invention is configured as described above, and the voltage drop is calculated by detecting the load current and considering the resistance value of the circuit, or by directly detecting the terminal voltage of the load and reducing the voltage drop. Since the output voltage of the rectifier is controlled so as to compensate the calculated voltage drop value, it is possible to keep the terminal voltage of the load within a predetermined allowable value.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, a voltage drop compensator 6 is connected to a gate controller 5 for controlling the output voltage of the rectifier 2. The gate controller 5 controls the output of the rectifier 2 so that the difference between the output voltage of the rectifier 2 and the reference voltage becomes zero. The voltage drop compensator 6 calculates the voltage drop by multiplying the load current obtained by the DC current transformer 8 by the preset resistance value of the cable 7, and gives the gate controller 5 a correction voltage signal. That is, the output voltage of the rectifier 2 input to the gate control device 5 is negatively corrected by the signal given from the voltage drop compensating device 6 and compared with the reference voltage. Therefore, the output voltage of the rectifier 2 is always the load 4
It is maintained at a value obtained by adding a voltage commensurate with the voltage drop until then, and the terminal voltage of the load 4 becomes constant regardless of the voltage drop of the circuit.

As another embodiment, FIG. 2 shows an example in which the terminal voltage of the load 4 is directly input to the voltage drop compensator 6. The voltage drop compensator 6 compares the preset allowable voltage value of the load with the terminal voltage value of the load 4, and gives the difference to the gate controller 5. The output voltage of the rectifier 2 is controlled in the same manner as in the embodiment of FIG. 1, and the terminal voltage of the load 4 is constant regardless of the voltage drop of the circuit.

[0011]

According to the present invention, various problems due to the voltage drop between the DC power supply device and the load as in the prior art are solved and the main circuit device does not need to be changed, so that the structure is simplified, It is possible to provide a highly reliable DC power supply device.

[Brief description of drawings]

FIG. 1 is a single wire connection diagram showing an embodiment of a DC power supply device of the present invention.

FIG. 2 is a single wire connection diagram showing another embodiment of the present invention.

FIG. 3 is a single wire connection diagram showing a conventional DC power supply device.

[Explanation of symbols]

 1 ... Transformer 2 ... Rectifier 3 ... Battery 4 ... Load 5 ... Gate control device 6 ... Voltage drop compensator 7 ... Cable 8 ... DC current transformer

Claims (1)

[Claims] 1. A rectifier connected to a transformer to supply a minute charging current to a battery and DC power to a load via a cable, and a rectifier output signal and a reference signal for detecting a load current or a load terminal voltage. A gate control device for controlling the output of the rectifier so that the difference between the voltage drop and the output voltage of the rectifier is zero, and a voltage drop compensating device for giving the gate control device a correction signal for the voltage drop based on the cable. DC power supply.