JP2008125283A - Power converter system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce an electromagnetic wave radiated from a main circuit board on which a semiconductor switching element is mounted, while suppressing cost increase and a large size of a power converter system. <P>SOLUTION: A control circuit board 201 is arranged on the main circuit board 101 so that it may confront the main circuit board 101, and metal plates 503 to 506 are arranged so that space between the main circuit board 101 and the control circuit board 201 may be surrounded from a side. Shield space to shield a switching portion 104 mounted on the main circuit board 101 against the electromagnetic wave is constituted together with ground layers 507a, 507b. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a power converter, and is particularly suitable for application to electromagnetic wave radiation countermeasures for a power converter.

In order to convert input power obtained from a commercial AC power source into power of a predetermined frequency by a semiconductor switching element and output the power, a power conversion device such as an inverter is used.
FIG. 4 is a perspective view showing an external configuration of a conventional power converter.
In FIG. 4, the power conversion device is provided with a main circuit board 901 that constitutes a switching circuit and a control circuit board 902 that constitutes a control circuit. The main circuit board 901 controls a switching operation such as a semiconductor switching element. An electronic component 904 is mounted, and an electronic component 904 that controls the switching operation is mounted on the control circuit board 902.

In the power conversion device, in order to respond to the demand for miniaturization of the power conversion device, the control circuit board 902 is generally disposed on the main circuit board 901 in close proximity.
Further, for example, in Patent Document 1, in order to block electromagnetic waves radiated from the main circuit board 901, a metal chassis is disposed between the main circuit board 901 and the control circuit board 902 to control the main circuit board 901. A method of spatially separating the circuit board 902 is disclosed.
JP-A-8-214549

However, in the power conversion device of FIG. 4, when a switching operation such as a semiconductor switching element is performed, electromagnetic waves are radiated from the main circuit board 901, and electromagnetic waves leaking outside cannot satisfy the EMI standard of the product. was there.
Further, when the control circuit board 902 is disposed close to the main circuit board 901, the intensity of the electromagnetic wave reaching the control circuit board 902 from the main circuit board 901 becomes strong, and the control circuit mounted on the control circuit board 902 However, there is a problem that it becomes easy to cause malfunction.

Further, in the method disclosed in Patent Document 1, in order to block electromagnetic waves radiated from the main circuit board 901, it is necessary to cover the entire power conversion device with a metal casing or the like, which increases the cost and power conversion. There was a problem that the apparatus was enlarged.
Accordingly, an object of the present invention is to provide a power conversion device capable of reducing electromagnetic waves radiated from a main circuit board on which a semiconductor switching element is mounted while suppressing an increase in price and size of the power conversion device. It is to be.

  In order to solve the above-described problem, according to the power conversion device of the first aspect, the switching circuit is mounted, the main circuit board having the first ground layer formed on one surface, and the switching control of the switching circuit is performed. A control circuit is mounted, is disposed on the main circuit board so as to face the main circuit board, and has a second ground layer formed on one surface, and the main circuit board and the control circuit board A conductive plate or a conductive sheet that is disposed so as to surround a space between the first and second ground layers and constitutes a shield space for electromagnetically shielding the switching circuit together with the first and second ground layers.

Thereby, by enclosing the space between the main circuit board and the control circuit board with the conductor plate or the conductive sheet, the switching circuit mounted on the main circuit board can be confined in the shield space, and the power conversion device It is possible to reduce electromagnetic waves radiated from the main circuit board on which the semiconductor switching element is mounted while suppressing an increase in price and size.
According to a second aspect of the present invention, the control circuit mounted on the control circuit board is disposed outside the shield space.

  As a result, the switching circuit mounted on the main circuit board can be confined in the shield space, and the control circuit mounted on the control circuit board can be disposed outside the shield space. Even in the case of being placed close to the main circuit board, it is possible to weaken the intensity of the electromagnetic wave reaching the control circuit board, while suppressing the increase in price and size of the power converter, It is possible to prevent malfunction of the control circuit mounted on the control circuit board.

  As described above, according to the present invention, the switching circuit mounted on the main circuit board can be confined in the shield space while using the first and second ground layers as the shield layers. It is possible to reduce electromagnetic waves radiated from the main circuit board on which the semiconductor switching element is mounted while suppressing an increase in price and size.

Hereinafter, a power converter according to an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing a schematic configuration of the power conversion apparatus according to the first embodiment of the present invention.
In FIG. 1, the power conversion device includes a main circuit board 101 constituting a switching circuit and a control circuit board 102 constituting a control circuit. The main circuit board 101 and the control circuit board 102 are accommodated in a housing 401. Has been.

  Here, the main circuit board 101 converts the AC voltage input via the power supply line 102 into a DC voltage, and the DC voltage obtained by the rectifier 103 has a predetermined frequency by switching operation. A switching unit 104 that converts the voltage into a voltage and outputs the voltage via a voltage output line 105 is provided. As the switching element provided in the switching unit 104, for example, a power MOSFET, a bipolar transistor, or the like may be used in addition to an IGBT (Insulated Gate Bipolar Transistor).

  Further, the control circuit board 202 includes a CPU unit 202 that performs arithmetic processing for controlling the switching operation in accordance with a program stored in the memory unit 203, a memory unit 203 that stores a program for operating the CPU unit 202, and an on / off function. A communication control unit 204 that outputs a signal for performing off control and frequency control to the switching unit 104 via the communication signal line 302 is provided. Note that the power of the CPU unit 202, the memory unit 203, and the communication control unit 204 can be supplied from the rectifying unit 103 via the power line 301.

When an AC voltage is input to the rectifying unit 103 via the power supply line 102, the AC voltage is converted into a DC voltage by the rectifying unit 103 and sent to the switching unit 104, and the AC voltage is converted to the rectifying unit 103. The voltage is rectified and transformed at 103, and is supplied as a power supply voltage to the CPU unit 202, the memory unit 203, and the communication control unit 204 via the power supply line 301.
Then, the CPU unit 202 performs arithmetic processing for controlling the switching operation according to the program stored in the memory unit 203, and sends a signal for performing on / off control or frequency control via the communication control unit 204. Thus, switching control of the switching unit 104 is performed. Then, the switching unit 104 performs a switching operation according to the control from the CPU unit 202, thereby converting the DC voltage obtained by the rectifying unit 103 into a voltage having a predetermined frequency and outputting the voltage via the voltage output line 105. .

FIG. 2 is a perspective view showing an external configuration of the power conversion device according to the first embodiment of the present invention.
In FIG. 2, a ground layer 507 b is formed on one surface of the main circuit board 101, and electronic components constituting the rectifying unit 103 and the switching unit 104 in FIG. 1 are mounted. In addition, a ground layer 507a is formed on one surface of the control circuit board 202, and electronic components 508 constituting the CPU unit 202, the memory unit 203, and the communication control unit 204 of FIG. The control circuit board 202 is disposed on the main circuit board 101 so as to face the main circuit board 101. The main circuit board 101 may be provided with heat radiating fins for radiating heat generated in the switching unit 104.

  Here, as a method of forming the ground layers 507 a and 507 b on one surface of the control circuit board 202 and the main circuit board 101, the ground layers 507 a and 507 b are respectively provided in the control circuit board 202 and the main circuit board 101. Alternatively, the ground layers 507 a and 507 b may be formed on the front surface or the back surface of the control circuit board 202 and the main circuit board 101.

In the power conversion device, the metal plates 503 to 506 are arranged so that the space between the main circuit board 101 and the control circuit board 202 is surrounded from the side, and the switching unit 104 mounted on the main circuit board 101. A shield space for electromagnetically shielding is formed together with ground layers 507a and 507b.
As a result, the switching unit 104 mounted on the main circuit board 101 can be confined in the shield space while using the ground layers 507a and 507b as the shield layers, and the increase in cost and size of the power conversion device can be suppressed. Meanwhile, it is possible to reduce electromagnetic waves radiated from the main circuit board 101 on which the switching unit 104 is mounted.

Of the electronic components 508 mounted on the control circuit board 202, those that are likely to cause a malfunction due to electromagnetic waves radiated from the main circuit board 101 are constituted by the metal plates 503 to 506 and the ground layers 507a and 507b. You may make it mount in the control circuit board 202 so that it may arrange | position outside a shield space.
As a result, the switching unit 104 mounted on the main circuit board 101 is confined in the shield space, and the CPU unit 202 and the memory unit 203 mounted on the control circuit board 201 can be arranged outside the shield space. Even when the control circuit board 201 is disposed close to the main circuit board 101, it is possible to reduce the intensity of the electromagnetic wave reaching the control circuit board 201 from the main circuit board 101. Malfunctions of the CPU unit 202 and the memory unit 203 mounted on the control circuit board 201 can be prevented while suppressing increase in price and size of the device.

  In order to enhance the shielding effect of the shield space constituted by the metal plates 503 to 506 and the ground layers 507a and 507b, the metal plates 503 to 506 and the ground layers 507a and 507b are electrically connected to each other. 506 and the ground layers 507a and 507b may be kept at an equipotential, or the metal plates 503 to 506 and the radiating fin are electrically connected to make the metal plates 503 to 506 and the radiating fin an equipotential. You may make it keep.

In the embodiment of FIG. 2, the method of surrounding the entire electronic component mounted on the main circuit board 101 with the metal plates 503 to 506 has been described. However, among the electronic components mounted on the main circuit board 101, electromagnetic waves are radiated. Only the electronic components to be performed may be surrounded by the metal plates 503 to 506.
In the embodiment of FIG. 2, in order to shield the switching unit 104 mounted on the main circuit board 101, the metal plates 503 to 506 are enclosed so that a space between the main circuit board 101 and the control circuit board 201 is surrounded. Although the method of arranging the metal plate has been described, a conductive sheet may be used instead of the metal plates 503 to 506.

FIG. 3 is a perspective view showing an external configuration of the power conversion apparatus according to the second embodiment of the present invention.
In FIG. 3, this power converter is provided with metal plates 603 to 606 in which holes 609 are arranged in the form of dots instead of the metal plates 503 to 506 in FIG. 2. And the shield space which electromagnetically shields the switching part 104 mounted in the main circuit board 101 is comprised by the metal plates 603-606 with the ground layers 507a and 507b. In addition, the diameter of the hole 609 formed in the metal plates 603 to 606 can be set so that the electromagnetic wave radiated from the switching unit 104 does not leak to the outside.

As a result, the switching unit 104 mounted on the main circuit board 101 can be confined in the shield space while using the ground layers 507a and 507b as the shield layers, and the increase in cost and size of the power conversion device can be suppressed. On the other hand, the electromagnetic wave radiated from the main circuit board 101 on which the switching unit 104 is mounted can be reduced, and the air permeability between the shield space and the outside can be ensured. It is possible to suppress the temperature rise of the switching element.
In the embodiment of FIG. 3, the method of providing the holes 609 in the metal plates 603 to 606 has been described in order to ensure the air permeability between the shield space and the outside, but a mesh structure may be used instead of providing the holes 609. .

It is a block diagram which shows schematic structure of the power converter device which concerns on 1st Embodiment of this invention. It is a perspective view which shows the external appearance structure of the power converter device which concerns on 1st Embodiment of this invention. It is a perspective view which shows the external appearance structure of the power converter device which concerns on 2nd Embodiment of this invention. It is a perspective view which shows the external appearance structure of the conventional power converter device.

Explanation of symbols

101, 501, 601 Main circuit board 102 Power supply line 103 Rectifying unit 104 Switching unit 105 Voltage output line 201, 502, 602 Control circuit board 202 CPU unit 203 Memory unit 204 Communication control unit 301 Power line 302 Communication signal line 401 Housing 503 to 506, 603 to 606 Metal plate 507a, 507b, 607a, 607b Ground layer 508, 608 Electronic component 609 hole

Claims (2)

A main circuit board on which a switching circuit is mounted and the first ground layer is formed on one surface;
A control circuit that performs switching control of the switching circuit, is disposed on the main circuit board so as to face the main circuit board, and has a second ground layer formed on one surface;
A conductor plate or a conductive sheet which is disposed so as to surround a space between the main circuit board and the control circuit board, and which constitutes a shield space for electromagnetically shielding the switching circuit together with the first and second ground layers. A power conversion device comprising:   The power converter according to claim 1, wherein a control circuit mounted on the control circuit board is disposed outside the shield space.

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