JP3512457B2 - Power converter - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power converter constructed by combining and connecting a plurality of power modules. 2. Description of the Related Art A power module used in a power converter of this type includes a bipolar transistor and an IGBT.
(Insulated gate bipolar transistor) A module structure in which various high-speed switching power devices such as a power MOSFET are housed in a case, not limited to the case. [0003] One module each containing, for example, one antiparallel circuit of an IGBT and a diode is 1in1, 2
The one stored individually is called 2in1. Recently, an intelligent power device or an IP in which an electronic circuit for protecting the power device is housed in one module is described.
M and the like are often used. FIG. 7 shows a configuration of a cooling stack for cooling a power module of a power converter, and FIG. 8 shows a circuit configuration of a power converter configured by a single-phase inverter circuit. [0005] For example, eight power modules 1 each composed of an antiparallel circuit of an IGBT and a diode are used, which are directly mounted on a mounting block 2b of a cooling fin 2 composed of a heat radiating section 2a and a mounting block 2b. The cooling fins 2 are configured to transport heat of the heat radiating portion 2a and the mounting block portion 2b to the heat radiating portion 2a by a heat pipe or the like. Each of the eight power modules 1 is connected in parallel with each other, and the parallel circuits are connected in series two by two to form each arm. Then, a series circuit of the snubber capacitor 3 and the snubber resistor 4 is connected in parallel to the parallel circuit of each arm. [0007] Both ends of each arm are connected to DC terminals P and N, and the connection point of each power module 1 of each arm is connected to AC terminals U and X. Snubber capacitor 3
The snubber resistor 4 is mounted near the power module 1 as much as possible to suppress a surge voltage due to high-speed switching. In the cooling stack, the power module 1 is mounted on the mounting block 2b of the cooling fin 2. When the number of the power modules 1 is large, the cooling stack is usually mounted on both sides of the mounting block 2b. Also, the mounting block 2 of the cooling fin 2
b, in addition to the power module 1, the snubber capacitor 3, the snubber resistor 4, and the power module 1
A resistor or the like that constitutes the drive circuit is mounted. [0010] For example, Japanese Patent Publication No. 5-300079 discloses a method in which a plurality of power modules are mounted on cooling fins, and then the connection of the power modules and the attached peripheral parts are wired with a power board. However, even with this method, the assembling workability of attaching many parts to the cooling fins cannot be sufficiently improved. The power module 1 has a small rated capacity. In FIG. 8, one arm is connected in parallel with two arms. In a 500 KVA class three-phase inverter device, about five to seven arms are connected in parallel. Many power conversion devices having a configuration are employed. When the number of power modules 1 connected in parallel increases as described above, it is necessary to connect power modules in parallel with electrical characteristics such as switching characteristics and saturation voltage in order to improve the current balance of each power module. . For this reason, in the conventional cooling stack of a power converter, workability for mounting many components is poor, and when one of the power modules is damaged, the power module and the electric characteristics are not improved. It was necessary to replace the power module with a suitable power module, and repair on the user side was difficult. For this reason, the user had to purchase the cooling stack itself as a spare part, but the cooling fins constituting the cooling stack are expensive due to a special structure requiring a heat pipe or the like for cooling. The stack is expensive, and the cooling stack can be repaired only by the manufacturer, so that it takes a long time to recover from the failure. Further, when an excessive current flows in the power module, there is a problem that the case is broken at the time of destruction and the surrounding circuit components are stained. Therefore, at the time of destruction, there is a problem that the surrounding circuit components must be replaced. Was. FIG. 9 shows an assembly diagram and a circuit diagram of one phase of the three-level converter circuit.
As shown in (b), the four power modules 11 and 12
, 13 and 14 are connected between DC terminals P and N,
Diode 5 in series circuit of power modules 12 and 13
The series circuits 1 and 52 are connected in parallel with the polarity shown in the figure, and the DC terminal O is connected to the connection point of the diodes 51 and 52. AC is an AC terminal. As shown in FIG. 9 (a), the assembling is performed by using rectangular power modules 11, 12, 13 and 1.
And the diodes 51 and 52 are arranged next to the power modules 12 and 14, respectively. In this state, the collector C of the power module 11 is connected to the DC terminal P by the connection conductor 61. The emitter E of the power module 11, the collector C of the power module 12 and the cathode K of the diode 51 are connected to the connecting conductor 6
2, the emitter E of the power module 12, the collector C of the power module 13 and the AC terminal AC are connected by a connecting conductor 63, and the emitter E of the power module 13, the collector C of the power module 14 and the anode A of the diode 52 are connected. They are connected by the connecting conductor 64, and the anode A of the diode 51, the cathode K of the diode 52 and the DC terminal O
Are connected by a connection conductor 65, and the emitter E of the power module 14 and the DC terminal N are connected by a connection conductor 66. However, with such an assembly configuration,
Since the number of power modules and diodes is large in the entire three-level converter circuit, when the power module is mounted on a cooling fin as shown in FIG. 7, the space factor becomes worse, and between the DC terminals P, O, N The distance becomes longer and each power module 11 ~ 14 and diode 5
There is a problem that the inductance of the connection conductors 61 to 66 of 1, 52 becomes large. For this reason, there has been a problem that the cooling stack becomes large, heavy and expensive. Further, since the inductance of the connection conductor increases, the surge voltage during the high-speed switching operation of the power module also increases, and there is a problem that the snubber capacitor and the snubber resistor also become large. As described above, in the power conversion device, there is a demand for downsizing and weight reduction of the device, ease of handling, reduction of the price including spare parts, improvement of reliability, and the like. However, the conventional power converter cannot meet the demand. That is, in the conventional power converter, the workability of assembling when attaching the power module to the cooling fins is poor, and there are problems such as a decrease in workability and safety in handling. Further, since it is necessary to select and combine electric characteristics of power modules used in parallel connection,
Power modules and snubber capacitors, snubber resistors,
Although it is necessary to handle the cooling fins in units of a cooling stack that is integrally assembled, there is a problem that the spare parts are extremely expensive when preparing the cooling stack as spare parts in the past. Since it is possible, it is necessary to request repair from a maker. However, since the cooling stack is large, it is difficult to handle the cooling stack, and there is a problem that the transportation cost and the like increase. Further, the maker itself has a poor workability in assembling the cooling stack, and handling is difficult, and assembling the apparatus is troublesome. In addition, the wiring inductance of the connection conductor increases, and therefore, the surge voltage of the power module increases, so that there is a problem that the capacity of the snubber capacitor and the snubber resistor increases and the voltage utilization rate of the power module decreases. Further, since the utilization rate of the mounting space for the power module is poor, the space for the mounting block portion of the cooling fins also increases, and there is a problem that the cooling stack becomes large, heavy, and expensive. Accordingly, the present invention provides a power conversion device that facilitates handling of a cooling stack, facilitates assembly and inspection work, and facilitates selection of electrical characteristics of a power module. Means for Solving the Problems The invention corresponding to claim 1 is:
An arm of the power converter is provided in a power converter including a plurality of power modules, a power board for electrically connecting the plurality of power modules, and cooling fins for cooling the plurality of power modules. <br/> At least two or more characteristics-selected power modules
Constituting one component units in the power board for electrical connection by placing, attached it to the cooling fin part single
It is a place to be. In the invention corresponding to claim 1, the power board on which the power modules are arranged is handled as a component unit. Therefore, handling becomes easy, and workability at the time of assembling the apparatus and workability of inspection can be improved. Further, the electric characteristics of the power module can be selected for each power board. For this reason, the sorting operation can be performed easily and accurately, and the assembler and the user do not need to pay special attention to the parallel connection of the power modules, and the assembling of the cooling stack and the operation at the time of failure can be facilitated. Embodiments of the present invention will be described below with reference to the drawings. First Embodiment As shown in FIG. 1, four rectangular power modules 111 and 11 are provided at a central portion on one surface side of a rectangular board 15.
2, 113 and 114 are vertically arranged in the longitudinal direction of the board 15 two by two.
12, 113, 114 are screwed from the other side of the board 15
The power board 17 with the power module is fixed by stopping at 6, 16,.... Power board 1 with power module
7 also has snubber resistors 141, 142, 143, 144 at the four corners on the other side of the board 15, respectively, and power modules 111, 112, 1, 1 at the long edges.
The snubber capacitors 131, 132, 133, and 134 are mounted so as to be located outside the positions 13 and 114. The power modules 111, 112, 1
13, 114, snubber capacitors 131, 132, 13
3, 134 and snubber resistors 141, 142, 143,
Power board 1 with power module with 144 installed
7 is handled as a power board for each component. As shown in FIG. 2, for example, the two power boards 171 and 172 with the power module thus constructed are mounted on both sides of the mounting block portion 12b of the cooling fin 12 comprising the heat radiating portion 12a and the mounting block portion 12b. Are mounted in contact with each other to form a cooling stack. The mounting of the power boards 171 and 172 to the mounting block portion 12b is performed by the respective power boards 171 and 172.
, 172 power modules 11 (111, 112)
, 113, 114) in the holes made at the four corners.
5 are screwed from the other side through mounting screws 18, 18,.... The function of the cooling stack is as follows.
The heat generated in the second mounting block portion 12b is transported to the heat radiating portion 12a by a heat pipe or the like and released, so that each power module 11 is cooled. In the cooling stack thus configured, a total of eight power modules 11 are mounted on both sides of the mounting block 12b of the cooling fins 12, so that the weight is 40 to 50 kg and the volume is 0.1 kg. 03m
^Third place, handling is very difficult. However, the four power modules 111,
Power board 171 to which 112, 113 and 114 are attached
, 172 in parts, the weight and volume handled are about 1/8 to 1/10 of the cooling stack.
Handling becomes very easy. Therefore, the work at the time of assembling the power converter is facilitated, and the workability is improved. Further, replacement work when the power module 11 breaks down becomes easy. In addition, in order to connect the power modules 11 in parallel, it is necessary to select and combine electrical characteristics.
Since such a sorting operation can be performed on a power board basis, if a sorting and combination of power boards is prepared in advance, the power module 11 can be replaced on a power board basis when the power module 11 breaks down. It will be easier. Further, since the power board is handled in units of a power board, spare parts for component replacement can be handled and stored in units of the power board, so that the handling and storage of the spare parts can be facilitated and the price is very low. . Second Embodiment The same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description is omitted. As shown in FIG. 3, a shielding member 20 is provided on one side of the board 15 so as to surround the power modules 111 to 114 in a U-shape. That is, the shielding member 20 shields between the power modules 111 to 114 and also shields the outside of the long side of each of the power modules 111 to 114. In such a configuration, even if the power modules 111 to 114 are damaged by an excessive current and an arc is generated from the power module, the arc is cut off by the shielding member 20 so that other normal power The module can be reliably prevented from being damaged by the arc from the damaged power module. Therefore, when the power module is damaged, only the damaged power module needs to be replaced, and the other normal power modules can be reused, so that the repair of the failure becomes easy and the failure recovery price can be reduced economically. . In the first and second embodiments, a total of eight power modules are mounted on both sides of the mounting block of the cooling fin.
Although the case where a plurality is attached has been described, the number is not necessarily limited to this, and for example, a total of six
The number may be two, and the point is that the number can be determined in a predetermined unit of the circuit of the power converter. In the first and second embodiments, a snubber capacitor and a snubber resistor are attached to the same board as the power module as peripheral parts attached to the power module.
Other circuit components such as a base resistor of a power module may be mounted on the same board, and the attached peripheral components mounted on the same board are not particularly limited. Further, when a cooling stack is formed by attaching a power board of each component to which a power board is attached to a cooling fin, a screw 16 for attaching a power module to the board is used when the power board is attached to the cooling fin. In order to adjust the dimensions with the bolts 18, the bolts may be loosened once and tightened again. This does not reduce the effect of the present invention. Third Embodiment This embodiment describes the case of a three-level converter circuit, and the circuit configuration for one phase is the same as the circuit configuration shown in FIG. 9B. As shown in FIG. 4, a circuit is assembled by four rectangular power modules 211, 212, 213, and 214 and one rectangular diode module 25. The diode module 25 is a 2-in-1 diode module in which two diodes are housed in one package. The power modules 211, 212,.
213, 214 and the diode module 25 are arranged vertically with the diode module 25 at the center and the long sides of each module being horizontal. The collector C of the power module 211 is connected to the DC terminal P via a connection conductor 261, and the emitter E of the power module 211, the collector C of the power module 212 and the cathode K of the diode module 25 are connected via a connection conductor 262. Then, the emitter E of the power module 212, the collector C of the power module 213 and the AC terminal AC are connected by a connecting conductor 263, and the emitter E of the power module 213, the collector C of the power module 214 and the anode A of the diode module 25 are connected. The connection is made by a connection conductor 264, the anode and cathode connection terminals AK of the diode module 25 and the DC terminal O are connected by a connection conductor 265, and the power module 2
The 14 emitters E and the DC terminals N are connected by connecting conductors 266. Each of these modules 211 to 214,
25, the connecting conductors 261 to 266 connected between the DC terminals P and N are connected to the respective modules 211 to 21.
4 and 25, they are arranged in a direction orthogonal to the long side direction, so that the distance between the connection conductors can be sufficiently reduced. Further, the distance between the DC terminals P and O and the distance between the DC terminals O and N can be minimized. Therefore, each of the power modules 211 to 21
The wiring inductance of the four connecting conductors 262 to 264 can be reduced, and the utilization rate of the mounting space can be improved.
Then, the surge voltage of the power module is reduced due to the reduction of the wiring inductance, so that it is possible to prevent the capacity of the snubber capacitor and the snubber resistor from increasing, thereby improving the voltage utilization rate of the power module. Further, by improving the utilization rate of the mounting space, the cooling stack can be reduced in size and weight, and the power converter itself can be reduced in size and cost. Fourth Embodiment This embodiment also describes the assembly of one phase of a three-level converter circuit, and the same parts as those of the third embodiment are denoted by the same reference numerals, and detailed description is omitted. In this embodiment, as shown in FIG. 5, 1-in-1 diode modules 251 and 252 in which one diode is housed in one package are used. This consists of four power modules 211, 212, 2
13 and 21 4 are arranged vertically with their long sides horizontal.
Diode modules 25 1, 25
2 are also arranged vertically with their long sides horizontal. The collector C of the power module 211 is connected to the DC terminal P via a connection conductor 361, and the emitter E of the power module 211, the collector C of the power module 212 and the cathode K of the diode module 251 are connected via a connection conductor 362. Then, the emitter E of the power module 212, the collector C of the power module 213 and the AC terminal AC are connected by a connecting conductor 363, and the emitter E of the power module 213, the collector C of the power module 214 and the diode module 252 are connected.
Of the diode module 251 and the DC terminal O are connected by the connection conductor 364.
651, the cathode K of the diode module 252 and the DC terminal O are connected by a connection conductor 3652, and the emitter E of the power module 214 and the DC terminal N are connected by a connection conductor 366. As described above, when the 1-in-1 diode modules 251 and 252 are used, each of the connection conductors 361 to 361 to 252 is used.
366 are the modules 211 to 214, 251, 25
2, the distance between the connection conductors can be sufficiently reduced. Accordingly, the wiring inductance of the connection conductor can be reduced and the utilization rate of the mounting space can be improved, so that the same operation and effect as in the third embodiment can be obtained. Fifth Embodiment This embodiment shows an assembly in a case where two power modules are connected in series between DC terminals P and N as shown in FIG. 6, in which two power modules 311 and 312 are connected. They are arranged vertically with their long sides horizontal. Then, the collector C of the power module 311 and the DC terminal P are connected by a connection conductor 461, and the emitter E of the power module 311 and the collector C of the power module 312 are connected by a connection conductor 462. And the DC terminal N are connected by a connection conductor 463. Also in this embodiment, the distance between the DC terminals P and N can be minimized, and the connection conductor used can be shortened. Therefore, the wiring inductance of the connection conductor can be reduced, and the utilization rate of the mounting space can be improved, so that the same operation and effect as in the third embodiment can be obtained. That is, the same effect can be obtained with a power conversion device other than the three-level converter circuit. As described above, according to the first aspect of the present invention, since a plurality of power modules and their peripheral circuit components are disposed on a component-by-component power board,
Workability at the time of assembling and inspecting the power converter can be greatly improved. In addition, since spare parts to be delivered to a user or the like can be prepared in units of power boards, the price of spare parts can be reduced, and handling can be facilitated. Therefore, failure recovery time and cost can be reduced. In addition, since the work of selecting and combining the electric characteristics in order to connect the power modules in parallel may be performed for each power board, a special power supply is required for assembling the power converter or replacing parts by the user. There is no need to sort modules, and work can be done on a power board basis. Accordingly, workability is improved in this respect as well, and it is possible to reduce the cost of the power converter, reduce the cost of spare parts, reduce the time required for recovery from a failure, and reduce the cost. [0069]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing a configuration of a power board according to a first embodiment of the present invention. FIG. 2 is a perspective view showing the appearance of the cooling stack in the embodiment. FIG. 3 is a diagram showing a configuration of a power board according to a second embodiment of the present invention. FIG. 4 is a diagram showing an arrangement relationship between a power module and connection conductors according to a third embodiment of the present invention. FIG. 5 is a diagram showing an arrangement relationship between a power module and connection conductors according to a fourth embodiment of the present invention. FIG. 6 is a view showing an arrangement relationship between a power module and connection conductors according to a fifth embodiment of the present invention. FIG. 7 is a perspective view showing the appearance of a cooling stack in a conventional example. FIG. 8 is a diagram showing a corresponding circuit configuration of the conventional example. FIG. 9 is a diagram showing a partial arrangement of power modules and connection conductors of a power conversion device including a three-level converter circuit in a conventional example, and a corresponding circuit configuration. [Description of Signs] 11, 111, 112, 113, 114 ... power module 12 ... cooling fins 131, 132, 133, 134 ... snubber capacitors 141, 142, 143, 144 ... snubber resistor 20 ... shielding members 211, 212, 213, 214 ... power modules 25, 251, 252 ... diode modules 261, 262, 263, 264, 265, 266 ... connecting conductors 311, 312 ... power modules 361, 362, 363, 364, 365, 366 ... connecting conductors 461, 462, 463 ... connecting conductor

Claims (1)

(57) [Claim 1] A plurality of power modules, a power board for electrically connecting the plurality of power modules, and a cooling fin for cooling the plurality of power modules. A power converter having at least two or more characteristic-selected power modules constituting an arm of the power converter, and electrically connecting the power modules.
Constituting one component units in a power board that performs power conversion apparatus characterized by a component unit for mounting it to the cooling fins.