JP3254918B2 - Power conversion unit for uninterruptible power supply - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an arrangement of a converter and an inverter comprising a switching element, wherein the former is disposed on the upper side and the latter is disposed on the lower side, and the radiation fin capacity is optimized, so that the overall size and weight are reduced. The present invention relates to a power conversion unit of an uninterruptible power supply device.

[0002]

2. Description of the Related Art A conventional example will be described below with reference to FIGS. 4A and 4B relate to a conventional example, and FIG. 4A is a front view thereof, and FIG. 4B is a side view thereof. In the figure, a converter 17 and an inverter 18 constituting a power conversion unit are horizontally arranged. The converter 17 and the inverter 18 have the same configuration.
The switching element 1, a snubber circuit 3 for overvoltage protection thereof, an electrolytic capacitor 12, a radiating fin 14 for radiating heat based on the power loss of the switching element 1, and an input / output It consists of terminals 6.

[0003] As shown in FIG.
And the snubber circuit 3 are disposed on both sides of the copper substrate 15, and a base 19 having high thermal conductivity is interposed between the switching element 1 and the radiating fins 14. The substrate 15 can reduce the inductance and the number of assembly steps by increasing the frequency of the switching element 1. Although not shown here, a fan is installed below the radiating fins 14 to generate an upward airflow to perform forced air cooling. As shown in the figure, the arrangement of the switching element 1 and the snubber circuit 3 is preferably one stage in terms of heat radiation, but when the current capacity of the converter 17 or the inverter 18 needs to be increased, it is usually limited to two stages. Array.

A circuit configuration of the converter and the inverter will be described with reference to FIGS. 5 and 6 which are circuit configuration diagrams of respective PWM (pulse width modulation) systems. FIG.
In this converter, three-phase AC power is input to terminals U, V, and W from the left side, and DC power is output from terminals P and N on the right side. In the inverter of FIG. 6, DC power is input to terminals P and N from the left and terminals u, v and w on the right.
Outputs AC power.

[0005]

Since the converter and the inverter have the same circuit configuration, in the prior art, the same units are horizontally arranged in terms of heat radiation effect, one of which operates as a converter and the other as an inverter. Was taken. However, from the viewpoint of space, the arrangement arranged vertically is more advantageous. In addition, the units are shared for standardization of design and manufacturing, and the radiating fins having the same configuration are used for each unit. However, in practice, the converter loses about 80% of the power loss compared to the inverter, so that the converter has more radiation fins than necessary on the converter side.
It was slightly overweight and costly.

[0006] The reason that the converter has a smaller power loss than the inverter is that the input voltage on the converter side is higher than the output voltage on the inverter side, and therefore the current flowing through the switching element is smaller. This is because the ratio of the current flowing to the diode side is high and the current flowing to the switching element side is small.

SUMMARY OF THE INVENTION An object of the present invention is to provide a power conversion unit of an uninterruptible power supply which solves the above-mentioned problems of the prior art and reduces the overall size and weight. .

[0008]

SUMMARY OF THE INVENTION The present invention relates to a converter having a switching element for converting AC power to DC power, and an inverter having a switching element for converting DC power to AC power. In a power conversion unit that generates a cooling airflow from below to above by a fan provided below and cools the inverter and the converter, the converter is arranged on the upper side and the inverter is arranged on the lower side, respectively. A radiation fin having a capacity corresponding to the total power loss of the converter and the inverter is provided in common for the converter and the inverter. Here, it is preferable that the module fins are arranged in parallel with the heat radiating base so as to have a variable capacity by selecting the number of the module fins.

[0009]

According to the present invention, the power loss is smaller than that of the inverter.
Therefore, since the converter that generates less heat is arranged on the upper side, the temperature rise is suppressed as compared with the reverse arrangement, and the common electrolytic capacitor and terminal parts are the same as those in the horizontal arrangement as in the conventional example. Side, so that the horizontal dimension can be shortened and therefore the occupied space can be reduced, and the capacity of the radiating fins corresponds to the total power loss of the converter and inverter,
For example, since the number of unit fins is determined, the size of the heat radiation fins can be reduced as compared with the conventional example.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a power conversion unit of an uninterruptible power supply according to the present invention will be described below with reference to the drawings. 1 (a) is a front view and FIG. 1 (b) is a side view of the embodiment. In this embodiment, the converter 7 is arranged on the upper side of the surface of the base 9 having high thermal conductivity, the inverter 8 is arranged on the lower side, and the radiating fins 4 are similarly installed on the back side. Further, as shown in FIG. 2A, the electrolytic capacitor 2 is provided on the left side and the terminal 6 is provided on the right side when viewed from the front of the base 9. The converter 7 and the inverter 8 have the same configuration, and both of them have the switching element 1 and the snubber circuit 3 arranged in a horizontal line so as to sandwich the substrate 5 from both sides. The arrangement of the switching element 1 and the snubber circuit 3 is preferably such that one line is preferable in terms of heat radiation as shown in the figure. It can be arranged up and down as much as two stages. When the substrate 5 is made of copper, the inductance can be reduced and the number of assembly steps can be reduced by increasing the frequency of the switching element 1 as in the conventional example.

The configuration of the heat radiation fins 4 will be described with reference to FIG. FIG. 3 is a perspective view of a radiation fin commonly used in this embodiment and the conventional example, and is generally illustrated. A unit fin 4a is provided in multiple stages with respect to a base 4b to which a heating element such as the switching element 1 is to be attached.
Here, the radiation fins 4 arranged in four stages are hard brazed via a brazing sheet 4c to which a hard brazing material is bonded. The unit fins 4a are a plurality of rectangular cylinders,
Here is a modularized structure of aluminum, four of which are arranged side by side and integrally formed with an upright flat plate. By using the radiation fins 4 having such a configuration, by selecting the number of the unit fins 4a, it is possible to easily provide an appropriate capacity according to the total radiation amount of the switching element 1 between the converter 7 and the inverter 8. .
Although not shown here, a fan is installed below the radiating fins 4 in the same manner as in the conventional example to generate upward airflow and perform forced air cooling.

Therefore, in this embodiment, since the converter 7 that generates about 80% of the power loss compared to the inverter 8 and that generates less heat in accordance with the power loss is arranged on the upper stage side, the arrangement is compared with the upside-down arrangement. As a result, the common electrolytic capacitor and the terminal can be arranged on the same side as compared to the horizontal arrangement as in the conventional example, so that the horizontal dimensions can be reduced, and the occupied space is reduced. Further, since the capacity of the radiating fins 4 is determined according to the total power loss of the converter 7 and the inverter 8, the size of the radiating fins can be reduced as compared with the conventional example.

Returning to FIG. 1A, a total of eight terminals 6 are vertically arranged. That is, the converter 7
, V, W for inputting three-phase AC power, then the output terminal P for DC power, and the terminals u, v, w for AC power output from the inverter 8, and The terminal N corresponds to the terminal P described above. FIG.
Is a circuit configuration diagram of this embodiment.

[0014]

According to the present invention, since the converter having less power loss and therefore less heat generation than the inverter is arranged on the upper stage side, the temperature rise can be suppressed as compared with the reverse arrangement, and the conventional example can be used. Compared to the horizontal arrangement, the common electrolytic capacitor and the terminal can be arranged on the same side, so that the horizontal dimension can be shortened and the occupied space can be reduced, and the capacity of the radiating fin can be reduced. It corresponds to the sum of the power loss of the inverter and the inverter, and is determined by, for example, the selection of the number of unit fins. As a result, the size, weight and cost of the entire unit can be reduced. In addition, there is an effect that the capacity of the capacitor is reduced for the following reasons. That is, the distance between the switching elements of the converter and the inverter can be reduced, the inductance can be reduced, and the ripple current by both switching elements can be easily offset.

[Brief description of the drawings]

1 (a) is a front view and FIG. 1 (b) is a side view of an embodiment according to the present invention.

FIG. 2 is a circuit configuration diagram of this embodiment.

FIG. 3 is a perspective view of a radiation fin shared between the embodiment and the conventional example.

4 (a) is a front view and FIG. 4 (b) is a side view of a conventional example.

FIG. 5 is a circuit configuration diagram of a conventional general converter.

FIG. 6 is a circuit configuration diagram of the inverter.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Switching element 2 Electrolytic capacitor 3 Snubber circuit 4 Radiation fin 4a Unit fin 4b Base 4c Brazing sheet 5 Substrate 6 Terminal 7 Converter 8 Inverter 9 Base

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) H02M 7/48 H02J 9/00

Claims (2)

(57) [Claims] 1. A fan having a switching element for converting AC power to DC power, an inverter having a switching element for converting DC power to AC power, and a fan provided below. In the power conversion unit that generates a cooling airflow from below to above and cools the inverter and converter, the converter is placed on the upper side and the inverter is placed on the lower side, and the total power loss of these converters and inverters A power conversion unit for an uninterruptible power supply, wherein a radiation fin having a corresponding capacity is provided in common for these converters and inverters. 2. The uninterruptible power supply unit according to claim 1, wherein the heat dissipating fins are configured such that modularized unit fins are juxtaposed to the heat dissipating base with a variable capacity by selecting the number. Power conversion unit.