JPH0956164A - Parallel connection method of power converters - Google Patents

Abstract

(57) Abstract: It is an object of the present invention to provide a parallel connection method of power converters that is strong against external noise and highly reliable. A first power converter (101) has an output line penetrating the primary side of a first current transformer (111) and connected in parallel with the first power converter (101). The output lines of the 2 to n power converters (102 to 10n) are passed through the primary sides of the 2 to nth current transformers (112 to 11m), respectively. Furthermore, all of the secondary side output lines of the first to n-th current transformers (111 to 11m) are arranged in the same direction in the n-th current transformer (11 to 11m).
n) through the primary side of the n-th current transformer (11n)
It is to connect a resistor (121) to the secondary output.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a parallel connection method for power converters such as inverter devices.

[0002]

2. Description of the Related Art A conventional parallel connection method for power converters is, as shown in FIG. 3, to connect an output line of a first power converter (101) to a primary side of a first current transformer (111). To penetrate
Second to second connected in parallel with the first power converter (101)
The output lines of the n power converters (102 to 10n) are passed through the primary side of the 2nd to mth current transformers (112 to 11m), respectively, and further the 1st to mth current transformers (111 to 11m). ) 2
Connect the dummy resistors (121 to 12n) for current / voltage conversion, which are respectively arranged in the control circuit (131), to the secondary outputs,
The voltage across each of the dummy resistors (121 to 12n) is added by an adder circuit (141) using an operational amplifier, and a plurality of outputs of the adder circuit (141) are connected in parallel to a power converter ( The detected current signal is a total current of 101 to 10 n), and the detected current signal is used to control the power converters connected in parallel. A method other than that shown in FIG. 3 is also known. This method, as shown in FIG. 4, includes first to nth power converters (201 to 20).
The output line after combining all the outputs of
1) is passed through the primary side of the current transformer (211), the dummy resistor (221) for current / voltage conversion arranged in the control circuit (231) is connected to the secondary side output, and the dummy resistor (2
The voltage across 21) is used as a detection current signal, and the detection current signal is used to control the power converters connected in parallel.

[0003]

However, such a method has the following problems. (A) Since the ground potential line of the control circuit driven by a low voltage is wired up to the current transformer provided at the output of the power converter through which a large current flows, noise is easily controlled on this ground potential line. There was a problem with the circuit malfunction. (B) In the method shown in FIG. 3, the operational amplifier is indispensable and the responsiveness becomes a problem. There is also a problem that the circuit becomes complicated and the reliability is lowered. (C) In the method shown in FIG. 4, since a total current after detecting all the outputs of the power converters connected in parallel is detected, a large current transformer is required. The current transformer was very expensive and very difficult to obtain. Further, the wiring length from the control circuit to the current transformer becomes very long, and the problem of the above item (a) becomes more serious. The present invention has been made in view of the above points, and an object of the present invention is to provide a method for connecting a power converter that solves these drawbacks.

[0004]

[Means for Solving the Problems] That is, the means for achieving the object is to pass the output line of the first power converter (101) to the primary side of the first current transformer (111). , First
The second to nth power converters (102 to 10n) connected in parallel with the second power converter (101) are respectively connected to the second output lines.
To the primary side of the current transformer (112 to 11 m) of
Further, all of the secondary side output lines of the first to mth current transformers (111 to 11m) are connected in the same direction to the nth current transformer (1).
1n) is passed through to the primary side, the secondary side output of the nth current transformer (11n) is connected to both ends of the resistor (121), and the total current when the power converter is connected in parallel is detected. Is the way.

[0005]

According to the parallel connection method of the present invention, the first to mth
The current-voltage converting dummy resistors (121 to 12n) are not directly connected to the secondary output lines of the current transformers (111 to 11m), but are provided in the vicinity of the control circuit (131). Since it is connected via the current transformer (11n), the n-th current transformer (11n) plays a role of electrical insulation. Therefore, the ground potential line of the control circuit (131) driven by a low voltage causes a large current. It is not necessary to wire the flowing current transformers (111 to 11m). An embodiment of the present invention will be described in detail below with reference to the drawings.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an explanatory view for explaining the general concept of the present invention, and FIG. 2 is a configuration diagram showing an embodiment thereof. In FIG. 1, the output of a first power converter (101) is shown. An output line of the second to n-th power converters (102 to 10n), which penetrates the wire to the primary side of the first current transformer (111) and is connected in parallel with the first power converter (101). To the primary side of the 2nd to mth current transformers (112 to 11m), and all the secondary side output lines of the 1st to mth current transformers (111 to 11m) in the same direction. 1 of the nth current transformer (11n)
This is a method of penetrating to the secondary side, connecting the secondary side output of the nth current transformer (11n) to both ends of the resistor (121), and detecting the total current when the power converters are connected in parallel.

In FIG. 2, two power converters are connected in parallel, and the output line of the first power converter (101) is passed through to the primary side of the first current transformer (111). The output line of the second power converter (102) connected in parallel with the first power converter (101) is connected to the first current transformer (112) 1
It penetrates to the next side. Furthermore, the first current transformer (111)
And the secondary side output lines of the second current transformer (112) are passed in the same direction to the primary side of the third current transformer (113) provided in the vicinity of the control circuit (31), respectively. Current transformer (11
A current / voltage conversion dummy resistor (121) arranged in the control circuit (131) is connected to the secondary output of 3), and the voltage across the dummy resistor (121) is used as a detection current signal. Use to control power converters connected in parallel. With such a configuration, the third current transformer (113) plays a role of electrical insulation so that the ground potential line of the control circuit (131) driven at a low voltage causes a large current to flow. Current transformer (111) and second current transformer (11)
It will not be wired up to 2). Furthermore, the third
The current transformer (113) is the same as the first current transformer (111)
Also, it becomes an adder of the secondary side output current of the second current transformer (112), and the adder circuit (141), which is conventionally indispensable and is constituted by an operational amplifier or the like, becomes unnecessary.

[0008]

As described above, according to the present invention, the ground potential line of the control circuit driven at a low voltage is wired up to the current transformer provided at the output of the power converter through which a large current flows. This eliminates the problem that the control circuit malfunctions due to noise on the ground potential line. In addition, an adder circuit (13
Since 1) is unnecessary, there is no problem of deterioration of reliability due to responsiveness and circuit complexity. Alternatively, it is not necessary to obtain an expensive and large-sized current transformer (211). Furthermore, it is extremely difficult to quantitatively capture the phenomenon of noise malfunction, and the effectiveness of the present invention for solving this problem is extremely high.

[Brief description of drawings]

FIG. 1 is an explanatory diagram illustrating a general concept of the present invention.

FIG. 2 is a configuration diagram showing an embodiment thereof.

FIG. 3 is a configuration diagram showing one example of the related art.

FIG. 4 is a configuration diagram showing two conventional examples.

[Explanation of symbols]

 101 power converter 102 power converter 10n power converter 111 current transformer 112 current transformer 11m current transformer 11n current transformer 121 resistance T1 input terminal T2 output terminal

Claims (1)

[Claims] 1. The output line of the first power converter (101) penetrates the primary side of the first current transformer (111) and is connected in parallel with the first power converter (101). The output lines of the second to nth power converters (102 to 10n) are respectively connected to the second to mth lines.
Of the current transformers (112 to 11m), and all of the secondary side output lines of the current transformers (111 to 11m) of the first to mth current transformers are the nth current transformer in the same direction. Bowl (11
n) through the primary side of the n-th current transformer (11n)
A parallel connection method of power converters, wherein a secondary output is connected to both ends of a resistor (121), and a total current when the power converters are connected in parallel is detected.