JPH06276697A - Changing-over device for power supply - Google Patents

Abstract

PURPOSE:To make small an electrical and mechanical stress applied on a load and a changing-over device for power supply by making smooth voltage change on the load side. CONSTITUTION:If an irregularity occurs in the power supply A and supply of voltage to a load stops, a closing control circuit 3 detects irregularity of power supply. Moreover, a time for starting voltage supply to the load from the power supply B is determined on the basis of the voltage of the power supply B as a normal power supply and a residual voltage of the load detected by a residual voltage detecting circuit 2 and a closing signal D is output to a power supply selection closing circuit 4 at this time. The power supply closing circuit 4 switches the switch of a switch unit 1 to the side of the power supply B depending on this closing signal D.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic power conversion device applied to a power supply system of a ship or the like.

[0002]

2. Description of the Related Art Conventionally, a power supply converter normally has two power supplies, and if for some reason an abnormality occurs in the power supply supplying the voltage to the load and the voltage is no longer supplied to the load, the other power supply will be switched to the other. It is switched to supply voltage to the load from a normal power source. As a method of switching the power source, there is a method of instantly and automatically switching when an abnormality occurs in the power source.

However, the operating load is generally the impedance of the load itself when the power supply is stopped,
The residual voltage is generated by the voltage generated by the built-in electric motor, and the load voltage gradually becomes zero. Therefore, there is also a method in which a closing delay using a timer is performed and the power supply is switched when the residual voltage of the load is considered to be sufficiently small.

[0004]

However, in the above-mentioned conventional method, the relationship between the phase of the voltage to be supplied and the phase of the residual voltage is unknown even when switching is performed instantaneously or by using a timer. Therefore, when the phase of the supplied voltage and the residual voltage is 180 ° out of phase, the
Double voltage is generated, the fluctuation of the power supply voltage becomes large, and the electrical and mechanical stress applied to the load and the power conversion device also becomes large, which causes failure or abnormality.

The present invention has been made in view of the above circumstances, and it is possible to suppress the stress on the load and the power conversion device when the power is switched and to supply the power so that the voltage change on the load side becomes smooth. The purpose is to provide a device.

[0006]

A power supply conversion device according to the present invention has a plurality of power supplies, and when an abnormality occurs in a power supply for supplying a voltage to a load, another normal power supply supplies the power to the load. A power supply switching device for switching a power supply so as to supply, a timing determining means for determining a timing of supplying a voltage to the load based on a phase difference between a voltage of the normal power supply and a residual voltage of the load, and the timing determination means. Supply means for supplying a voltage from the normal power source to the load based on the timing determined by the means.

[0007]

[Operation] When an abnormality occurs in the power supply that supplies the voltage to the load for some reason, the timing to start the voltage supply to the load from the phase difference between the power supply voltage of the normal power supply and the residual voltage of the load To decide. According to this timing, the switches and the like are switched so that the voltage is supplied from the normal power source to the load. As a result, it is possible to reduce fluctuations in the power supply voltage on the load side when power is supplied, and also to reduce electrical and mechanical stress on the load and the power supply conversion device.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows the functional configuration of the power conversion device according to the present invention. As shown in FIG. 1, power source A and power source B
Are both connected to the switch unit 1, and either the power supply A or the power supply B supplies the power supply voltage to the load according to the switching of the switch in the switch unit 1. The residual voltage detection circuit 2 detects the residual voltage of the load and notifies the closing control circuit 3 of this residual voltage.

The turn-on control circuit 3 monitors the voltage waveforms of the power supplies A and B, and if an abnormality occurs in the power supply supplying the voltage to the load for some reason, the normal voltage of the power supply and the residual voltage of the load. Determines the optimum time to start supplying power to the load, and outputs the closing signal D to the power supply selecting and closing circuit 4 at this determined time. The power supply selection input circuit 4 switches the switch of the switch unit 1 to the normal power supply side in response to the input signal D.

Next, the operation of this embodiment will be described with reference to FIG. The switch in the switch unit 1 is the power supply A
Is supplied to the power supply A side so as to supply the power supply voltage to the load.

Now, as shown in FIG. 2, at time t1,
When an abnormality occurs in the power supply A for some reason and the voltage supply from the power supply A is stopped, the amplitude a and the frequency of the residual voltage C generated in the load are gradually attenuated.

When the closing control circuit 3 detects an abnormality that has occurred in the power supply A, it compares the phases of the power supply voltage of the power supply B and the residual voltage of the load input from the residual voltage detection circuit 2, and the time when the phases overlap. Calculate t2. The closing control circuit 3 outputs a closing signal D to the power source selection closing circuit 4 at time t2.
The power supply selection input circuit 4 switches the switch of the switch unit 1 to the power supply B side in response to the input signal D, whereby the power-on processing is completed. As the power-on technique at the time when the phases are overlapped, a technique used for synchronous activation using two generators or the like can be applied. Further, in the embodiment, the power conversion device using the two power supplies A and B has been described, but it goes without saying that the number of power supplies is not limited to two.

[0013]

As described above in detail, according to the present invention,
When the abnormal power supply is switched to the normal power supply, the residual voltage of the load is detected, the appropriate power-on timing is determined from the residual voltage and the voltage of the normal power supply, and the power supply is switched at this timing Since the voltage can be reduced and the voltage change on the load side is smooth, the electrical and mechanical stress applied to the load and the power supply conversion device can be reduced. This makes it possible to improve the maintenance and maintainability of the load and the power supply conversion device.

[Brief description of drawings]

FIG. 1 is a block diagram showing a functional configuration of a power conversion device according to an embodiment of the present invention.

FIG. 2 is a timing chart for explaining a relationship between a power supply abnormality occurrence time and a voltage supply start time of a normal power supply in the embodiment.

[Explanation of symbols]

 1 Switch unit 2 Residual voltage detection circuit 3 Supply control circuit 4 Power supply selection supply circuit

Claims (1)

[Claims] 1. A power conversion device having a plurality of power supplies, wherein when an abnormality occurs in a power supply for supplying a voltage to a load, the power supply is switched so that the power is supplied from another normal power supply to the load. Timing determining means for determining the timing of supplying voltage to the load based on the phase difference between the voltage of the normal power source and the residual voltage of the load; and the load from the normal power source to the load based on the timing determined by the timing determining means. And a supply means for supplying a voltage to the power supply conversion device.