JP3181370B2 - Method of arranging power converter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for arranging a plurality of voltage-type inverters and a plurality of smoothing filters, and more particularly, to a common rectifier and a smoothing filter for converting AC power into DC power and inversely converting DC power into AC power. The present invention relates to a method for arranging power conversion devices when a plurality of voltage-source inverters are connected.

[0002]

2. Description of the Related Art Conventionally, there is a method of arranging a power converter including a rectifier for once converting AC power into DC power, a smoothing filter for smoothing DC, and a voltage type inverter for converting DC power into AC power. , As follows.
FIG. 3 is a diagram for explaining this, wherein 1 is a rectifier, 2
Denotes a smoothing filter, 3 denotes a voltage source inverter, and 4 denotes a motor.

When many voltage-type inverters 3 as shown in FIG. 3 are operated simultaneously, the rectifier 1 is commonly used as shown in FIG. 4, and the inverters 3A and 3B may be connected in parallel to a DC power supply. In this case, the smoothing filters 2A and 2B are connected to the inverters 3A and 3B with the shortest distance.
By connecting in this way, only one rectifier 1 is required and an economical power converter can be configured.

[0004] In order to make the structure more economical,
As shown in FIG. 5, a configuration in which the smoothing filter 2C is shared can be considered. In FIG. 5, the components are the same as in FIG. 4, but the smoothing filter 2C is shared like the rectifier 1, and one unit is shared by the inverters 3A and 3B. In this case, it is a matter of course that a capacitor having a necessary capacity for all the inverters 3A and 3B is provided, but the distance from the smoothing filter 2C to each of the inverters 3A and 3B needs to be shortest and low in inductance.

This is because the current is interrupted when the switching elements of the inverters 3A and 3B are turned on or off, and a switching surge voltage is generated due to the energy of the inductance Ls of the circuit. If the inductance Ls of the circuit is large, the surge voltage increases in proportion to the inductance Ls, and eventually the switching element and the motor 4 are destroyed.

[0006]

SUMMARY OF THE INVENTION
Conventionally, the economy when the smoothing filter 2C is shared as shown in FIG. 5 and the voltage-type inverters 3A and 3A as shown in FIG.
It has been desired to develop a method of arranging power converters that can take advantage of low inductance and low surge voltage when B has individual smoothing filters 2A and 2B.

Therefore, the present invention provides a method of arranging a power conversion device having both the economy when a smoothing filter is shared and the low inductance and low surge voltage when a voltage type inverter has a smoothing filter individually. The purpose is to provide.

[0008]

In order to achieve the above object, an invention according to claim 1 is a system comprising: a rectifier for converting AC power to DC power, and a rectifier connected in parallel to a DC terminal of the rectifier. And N voltage-source inverters for converting DC power into AC power, and two or more and less than N smoothing filters connected in parallel to the DC terminals of the rectifier and smoothing the DC output. A method for arranging power converters, characterized in that the inverters are distributed and arranged in several units between the inverters and the smoothing filter.

According to a second aspect of the present invention, there is provided a rectifier for converting AC power into DC power, and a rectifier connected in parallel to a DC terminal of the rectifier for converting DC power into AC power. N voltage source inverters including voltage source inverters having different current capacities, connected in parallel to the DC terminal of the rectifier, and smoothing the DC output.
And more than N filters and less than N filters,

In the vicinity of the smoothing filter, one of the inverters having a large current capacity is arranged.
A method of arranging power converters, wherein the remaining inverters are distributed between the smoothing filters.

[0011]

According to the invention corresponding to the first and second aspects, the number of smoothing filters is reduced, so that the economy is excellent, and the wiring inductance between the smoothing filters and the inverter can be reduced, so that the arrangement of inverters having a low switching surge voltage is achieved. Becomes possible.

[0012]

FIG. 1 is a diagram for explaining a first embodiment of the present invention. In FIG. 1, 1 is a rectifier, 2A and 2B are smoothing filters, 3A, 3B, 3C and 3D are voltage type inverters, and 4A, 4B, 4C and 4D are motors. Each of the inverters 3A to 3D does not have a smoothing filter by itself,
The smoothing filters 2A and 2B are connected to the DC circuit at a rate of at least two inverters or more. This is more economical than having the smoothing filters 2A and 2B for each of the inverters 3A and 3B as in the conventional example of FIG. Further, by disposing the smoothing filters 2A and 2B in a distributed manner, the distance from the inverters 3A and 3C to the smoothing filter 2 is shortened, thereby reducing the wiring inductance. As a result, the effect of suppressing the switching surge voltage is obtained.

In general, a surge voltage generated by switching is related to a wiring inductance Ls of a closed circuit formed by a smoothing filter and a switching element and a current Id controlled by the switching element, and the energy of the circuit is 1 / 2LsI ^2. It is proportional to d. For this reason, a limited number of smoothing filters 2 are distributed and arranged so that the wiring inductance Ls of each inverter 3 is minimized.

FIG. 2 shows another different embodiment of the present invention. In FIG. 2, the components are the same as those in FIG. In FIG. 2, when the energizing current of each of the voltage type inverters _{3A to 3E} is different, the energizing current is I _3A ≧ I _3B ≧ I _3C ≧ I _3D ≧ I _3E

The inverters 3A to 3E satisfy the following relationship.
Place. That is, the inverter 3A having a large current
The closer to the smoothing filter 2A. As a result, the energy に よ る LsI ² due to the wiring inductance Ls of each of the inverters 3A to 3E. Make d as small as possible and suppress the switching surge voltage.

In the above description, the rectifier is a diode rectifier, but the present invention is not limited to this. The present invention is also applicable to a converter using a thyristor or a self-extinguishing element. Also, a circuit example of a transistor inverter has been described as an example of an inverter, but the present invention is not limited to this, and can be applied to any circuit as long as it is a voltage type inverter that performs PWM control having voltage control capability. is there.

[0017]

According to the present invention described above, since the number of smoothing filters is reduced, the economy is excellent, and the wiring inductance between the smoothing filters and the inverter can be reduced. It is possible to provide a method of arranging the power conversion device that can be performed.

[Brief description of the drawings]

FIG. 1 is an array diagram of a power converter showing a first embodiment of the present invention.

FIG. 2 is an array diagram of a power converter according to a second embodiment of the present invention.

FIG. 3 is a diagram showing an example of a voltage source inverter.

FIG. 4 is a first arrangement diagram of a conventional power converter.

FIG. 5 is a second arrangement diagram of the conventional power converter.

[Explanation of symbols]

1 ... Rectifier, 2A, 2B ... Smoothing filter, 3A ~ 3E ...
Voltage type inverter, 4A-4E ... motor.

Claims (2)

(57) [Claims] 1. A rectifier for converting AC power into DC power, N voltage source inverters connected in parallel to DC terminals of the rectifier and converting DC power into AC power,
The rectifier is connected in parallel to a DC terminal, and is configured by two or more and less than N smoothing filters for smoothing the DC output, and the inverters are distributed and arranged between the smoothing filter and the smoothing filters. A method of arranging a power converter, comprising: 2. A rectifier for converting AC power into DC power, and a rectifier connected in parallel to a DC terminal of the rectifier for converting DC power into AC power and at least two units having different current capacities. And N or more voltage-source inverters including a power inverter and two or more and less than N smoothing filters connected in parallel to the DC terminal of the rectifier and smoothing the DC output. A method of arranging a power conversion device, comprising: arranging one of the inverters having a large current capacity in the vicinity of a filter and distributing the remaining inverters between the smoothing filters.