JPH11299246A - Parallel operation apparatus of switching power supply - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make possible the parallel operation of power supply having different capacities and characteristics, etc., by providing in a multi-input parallel operation apparatus a control circuit for each rectification device and also providing a control circuit of its inverter. SOLUTION: A control circuit 5 stored in a multi-input parallel operation apparatus 4 has detecting means for detecting an AC voltage and AC current of the input side of a converter 8 and DC output voltage, a power computing means for computing the input power by the inputted voltage and current, and a power setting means for comparing the rated capacity of a rectification device 1 with the power computed based on the power computing means to set a DC power of the rectification device 1. The control circuit 5 also has a driving-signal sending-out means for driving the switching elements of the rectification device 1 to send out at a predetermined DC voltage the DC power previously set based on the power setting means. A control circuit 6 also has the same function as the control circuit 5. Further, a control circuit 7 of an inverter 3 has a detecting means of the AC output voltage of the inverter 3, a constant-voltage controlling means. and a driving-signal sending-out means of the switching elements of the inverter 3. As a result, the parallel operation of switching power supply is made possible without any trouble.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a parallel operation device for operating a plurality of switching power supplies in parallel.

[0002]

2. Description of the Related Art FIG. 3 is a block diagram showing a conventional method of operating switching power supplies in parallel. The rectifiers 101 to 103 which have input the AC power supply perform AC / DC conversion and output DC power. However, in order to perform the interconnection operation on the DC side, the rectifiers 101 to 103 must be controlled to maintain a common DC voltage. . The DC power output from the rectifiers 101 to 103 is collectively input to the inverter 104, and the inverter 104 performs direct / interchange conversion of the input DC power and supplies AC power to the load 105.

[0003]

Generally, rectifiers are designed to operate in an isolated manner, and do not consider parallel operation. Therefore, various obstacles must be overcome when attempting to operate rectifiers having different manufacturers, rated capacities, and output characteristics in parallel. In other words, when attempting to connect a plurality of rectifiers to DC, it is necessary to control the DC power using a common DC voltage, and a situation in which the expected DC power cannot be supplied from rectifiers having different rated output voltages may occur. There is. To realize parallel operation,
It is necessary to adjust the output voltage for each parallel unit by adding a dedicated control device, and to set the allowable output in consideration of the output characteristics, which is very troublesome control. Also, when the number of parallel units is increased or decreased according to the load, or when the parallel units are started / stopped due to maintenance and inspection, it is necessary to take into account the characteristics of the parallel units each time.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned drawbacks of the prior art, and includes a detecting means for detecting an AC input voltage, a current, and a DC output voltage, and respective rectifiers. Power calculation means for calculating the AC input voltage and the AC input current detected from the rectifier, power setting means for setting the DC output by comparing the rated capacity of the rectifier and the power calculation value, and power at a predetermined DC voltage. A control circuit is provided for each of the rectifiers, the control circuit including drive signal transmitting means for driving a switch element of the rectifier so as to transmit the DC power set by the setting means. A constant voltage control means for an inverter which collectively inputs DC power transmitted from the device and converts the power into AC power, and an inverter for transmitting AC power based on the constant voltage control means. The control circuit of an inverter and a driving signal means for driving the switching element has been installed in the multi-input parallel operation device.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. The rectifiers 1 and 2 convert input commercial power (Ac) into DC power in converters 8 and 9 and are operated in parallel by a common DC voltage. DC outputs from the rectifiers 1 and 2 are collectively input to the inverter 3 and converted into AC power and output.

[0006] A multi-input parallel operation device 4 is provided so that parallel operation can be easily performed even when the rated capacity and output characteristics of the rectifiers 1 and 2 are different. A control circuit 6 corresponding to the rectifier 2 and a control circuit 7 corresponding to the inverter 3 are housed. The control circuit 5 includes a detection unit that detects and inputs an AC voltage, an AC current, and a DC output voltage on the input side of the converter 8, a power calculation unit that calculates the input AC voltage and the current, a rated capacity and a power of the rectifier 1. Power setting means for setting the DC power by comparing the power based on the arithmetic means with the switching element of the rectifier 1 to drive the DC power based on the power setting means at a predetermined DC voltage; A drive signal transmitting means is provided.

The control circuit 6 for the rectifier 2 also
Since it has the same function as the control circuit 5, the rectifier 1
Even if the rated capacity and output characteristics of the power supply and the power supply are different, the DC interconnection operation can be performed without any trouble.

The control circuit 7 of the inverter 3
Detecting means for detecting and inputting the AC output voltage of the inverter 3, constant voltage control means for controlling the inverter 3 with a constant voltage, and a drive signal for driving the switch element of the inverter 3 to transmit the AC power based on the constant voltage control means. It has sending means. Therefore, the DC power output from the rectifiers 1 and 2 can be collectively converted into AC power, and the constant-voltage controlled AC power can be transmitted.

[0009]

As described above, according to the switching power supply parallel operation device of the present invention, a plurality of rectifiers designed for single unit operation can be operated in parallel without any trouble, and the same load can be applied via the inverter. AC power can be supplied. Further, it is possible to cope with a case where the rated capacity and the output characteristics are different, and it is possible to flexibly cope with a change in load capacity and a change in power supply capability of the supply unit.

FIG. 2 shows an embodiment in which a power supply such as a UPS is connected to the input of the parallel operation device of the switching power supply according to the present invention. Parallel operation is easy.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a circuit configuration of a multi-input parallel operation device according to the present invention.

FIG. 2 is a block diagram when a UPS is connected to the input of the parallel operation device of the switching power supply according to the present invention.

FIG. 3 is a block diagram showing a parallel operation method of a switching power supply according to the related art.

[Explanation of symbols]

 1, 2 Rectifier 3 Inverter 4 Multi-input parallel operation device 5, 6, 7 Control circuit 8, 9 Converter

Claims (1)

[Claims] 1. Each rectifier is individually controlled so that a plurality of rectifiers having different rated capacities and output characteristics are operated in parallel on a DC output side, and the DC power output from the rectifier is collectively input. In the parallel operation of the switching power supply that controls the inverter so as to convert the power to AC power and supply the AC power to the load, detection means for detecting an AC input voltage and a current and a DC output voltage in each rectifier; A power calculating means for calculating a current, a power setting means for comparing the rated capacity of the rectifier with the power based on the power calculating means to set a DC output, and a DC power based on the power setting means, And a drive signal transmitting means for driving a switch element in the rectifier so as to transmit a voltage. Installed as well as parallel operation collectively the plurality of rectifier, a detection means for detecting an AC output voltage of the inverter, and the input collectively DC power of the plurality of rectifier device outputs a,
Constant voltage control means for controlling the inverter which converts the power into AC power and supplies the AC power to the load, with a constant voltage; and drive signal transmission means for driving a switch element in the inverter to transmit the AC power based on the constant voltage control means. By installing the control circuit of the inverter provided with each in the multi-input parallel operation device, the switching power supply comprising a plurality of rectifiers and the inverter is controlled collectively, characterized by the Parallel operation device.