JP6672605B2 - Power converter - Google Patents

Description

  The present invention provides a noise filter circuit for reducing the outflow of high-frequency noise generated by the switching operation of the power conversion device main body to the input power supply system, and disconnects the power conversion device main body from the input power supply system by fusing when a failure occurs. The present invention relates to a power conversion device including a filter circuit board having a fuse mounted thereon.

  A power conversion device that obtains power of a predetermined output voltage by switching input power at high speed by a semiconductor switching element such as an IGBT or a MOS-FET has advantages such as high efficiency, small size, and light weight. Spread is remarkable. However, high-frequency voltage and current components generated by the switching operation of the semiconductor switching element cause electromagnetic noise, and electromagnetic noise disturbance to peripheral devices is a major problem.

  In order to prevent this electromagnetic noise interference, the power conversion device is provided with, for example, electromagnetic noise (high-frequency noise) from the power conversion device main body to the input power system side before the power input section of the power conversion device main body. A noise filter circuit for reducing the outflow is provided. Particularly, recently, laws and regulations on the electromagnetic noise flowing out to the input power supply system side have been spread worldwide, and conducted noise (noise terminal voltage) and radiated noise (radiated electric field strength) are subject to various environmental conditions. The level to be reduced has been clarified.

  By the way, the design of the noise filter circuit has been developed by trial and error while relying solely on experience and know-how. The reason is that when the noise filter circuit is incorporated in the power conversion device, the undesired electromagnetic coupling between the noise filter circuit and the power conversion device main body becomes more difficult than when the various components constituting the noise filter circuit are combined alone. (Electrostatic coupling / electromagnetic coupling) occurs, and the effect of reducing electromagnetic noise is greatly deteriorated. In particular, when the noise filter circuit is housed together with the power conversion device main body in a metal housing, it is difficult to obtain a sufficient effect of reducing the electromagnetic noise.

  One of the causes of deterioration of filter characteristics due to undesired electromagnetic coupling is, for example, a linkage flux A crossing a power line 2 drawn from the noise filter circuit 1 to the outside of the device as shown in FIG. An induced current B flows through the power line 2 due to the linkage magnetic flux A crossing between the power lines 2. Then, the induced current B flows out of the device as it is via the power line 2, which causes an increase in the noise level flowing out of the power converter to the input power system side.

  Therefore, it has been considered that the power flux 2 is shortened so that the flux linkage A crossing the power flux 2 is reduced as much as possible, thereby reducing the noise caused by the flux linkage A. Further, as described in Patent Literature 1, for example, as shown in FIGS. 8A and 8B, a bypass capacitor 3 is provided in the immediate vicinity of a terminal block 4 for leading the power line 2 to the outside of a metal housing 10 in the power converter. Add. It has also been proposed that the induced current B induced in the power line 2 be returned through the bypass capacitor 3 inside the device, thereby reducing noise flowing out of the device.

However, when the bypass capacitor 3 is provided in the immediate vicinity of the terminal block 4, for example, the power input unit of the power converter must be constructed as shown in FIGS. I can't get it. FIG. 8A shows an example in which the bypass capacitor 3 is connected to the terminal block 4 of the power converter. FIG. 8B shows an example in which a circuit board 5 on which the bypass capacitor 3 is mounted is provided near the terminal block 4, and the power line 2 is connected to the terminal block 4 via the circuit board 5. . In FIGS. 8A and 8B, reference numeral 6 denotes a filter circuit board on which the noise filter circuit 1 including the capacitors C _X , C _Y1 , and C _Y2 and the reactor L is mounted.

  When the bypass capacitor 3 is provided in the immediate vicinity of the terminal block 4 in this way, it is unavoidable that the mounting cost of the bypass capacitor 3 increases. Therefore, conventionally, the power line 2 is often shortened as much as possible instead of mounting the bypass capacitor 3 to reduce the influence of the flux linkage A.

By the way, the power conversion device is generally provided with a fuse 7 for blowing out when a failure occurs and disconnecting the power conversion device from the input power supply system, as shown in FIG. 9, for example. Specifically, for example, as shown in FIG. 10, the fuse 7 is arranged in the immediate vicinity of the terminal block 4 of the filter circuit board 6 to which the power line 2 drawn from the outside of the metal housing 10 is connected. After the fuse 7, the filter components are arranged in a line in the order of the line capacitor C _X1 , the reactor L and the line capacitor C _X2 to form the filter circuit board 6.

Here, the fuse 7 has a role of protecting the power conversion device and preventing an electric shock due to the electric charge accumulated in the line capacitor _CX1 in the noise filter circuit 1. The fuse 7 is usually mounted on the filter circuit board 6 by, for example, soldering to a conductor pattern 8 formed in advance on the filter circuit board 6 on which the noise filter circuit 1 is mounted.

  However, when the fuse 7 is provided on the power input side of the filter circuit board 6 in this way, the linkage magnetic flux A crosses the fuse 7, and the fuse 7 causes an increase in the linkage magnetic flux area. . In order to solve such a problem, for example, Patent Document 2 discloses that an inductor is provided in a power line (conductive pattern) 2 that forms a pair with the conductive pattern 8 in which the fuse 7 is interposed, thereby reducing a common mode noise component. It is disclosed to reduce.

JP 2009-240037 A JP 2012-29404 A

  However, if an inductor is provided in the power line (conductive pattern) 2 that is paired with the conductor pattern 8 in which the fuse 7 is interposed as disclosed in Patent Document 2, the size of the filter substrate increases and the size of the filter circuit substrate 6 increases. The number of mounted components mounted on the device increases. Moreover, the inductor is more expensive than a capacitor or the like, which leads to an increase in the cost of the noise filter circuit 1 and thus the power converter.

  The present invention has been made in view of such circumstances, and its purpose is to mount a fuse on a filter circuit board provided on the power input side of the power conversion device main body, even if the fuse crosses the fuse. An object of the present invention is to provide a power conversion device including a noise filter circuit that can effectively reduce an outflow of an induced current to the outside of the device due to an alternating magnetic flux.

  A power conversion device according to the present invention basically includes a power conversion device main body that switches input power through a semiconductor switching element to generate an output power of a predetermined voltage, and is provided on a power input side of the power conversion device main body. And a noise filter circuit that reduces high-frequency noise generated by the switching operation of the power conversion device main body to the outside of the input power supply system.

Further, the noise filter circuit in the power converter according to the present invention is mounted on a single filter circuit board together with a fuse that is blown out at the time of failure and disconnects the power converter main body from the input power supply system. In particular, the filter circuit board is a line capacitor that is interposed between input power lines and constitutes a part of the noise filter circuit, from a terminal block side of the filter circuit board to which a power supply line of the input power supply system is connected, It is characterized in that filter components constituting the remaining part of the noise filter circuit excluding the discharge resistor for the line capacitor, the fuse, and the line capacitor are arranged in this order.
Further, it is preferable that the line capacitor is mounted in the vicinity of a terminal block of the filter circuit board to which a power supply line of the input power supply system is connected .

The filter circuit board is provided near and along a wall surface of a metal casing of the power conversion device, and a wiring pattern of a ground line of the filter circuit board is connected to the metal casing, and the filter circuit board is provided. It is preferable that the positive and negative wiring patterns of the power line are provided between the side surface of the metal housing and the wiring pattern of the ground line.
Preferably, the fuse is mounted on the filter circuit board while being shielded from a conductive layer forming a wiring pattern formed on the filter circuit board by a shielding member provided near the fuse. At this time, it is also preferable to connect a circuit element for induced current bypass, for example, a capacitor or a varistor for surge absorption, in parallel with the fuse.

According to the power conversion device including the filter circuit board having the above configuration, the induced current induced in the fuse due to the linkage magnetic flux passes through the line capacitor provided on the terminal block side of the filter circuit board. To return in the filter circuit board. Therefore, it is possible to effectively prevent the induced current induced in the fuse from flowing out of the device through the terminal block of the filter circuit board .

  In addition, since the discharge resistor for the line capacitor is mounted between the line capacitor and the fuse on the filter circuit board, when the fuse is blown, the discharge resistor is accumulated in the line capacitor via the discharge resistor. The discharged charge can be quickly discharged. As a result, electric shock due to the electric charge accumulated in the line capacitor can be reliably prevented. Therefore, according to the power conversion device according to the present invention, noise flowing to the outside of the device due to linkage magnetic flux can be effectively reduced only by setting the components mounted on the filter circuit board in the above-described arrangement order, and Electric shock when the fuse is blown can be reliably prevented. Therefore, its practical advantages are great.

FIG. 2 is a diagram illustrating a component mounting form of a filter circuit board provided in the power converter according to the first embodiment of the present invention, and a configuration example of a noise filter circuit. FIG. 9 is a diagram illustrating a component mounting form of a filter circuit board provided in a power converter according to a second embodiment of the present invention, and a configuration example of a noise filter circuit. FIG. 9 is a view showing a component mounting mode of a filter circuit board provided in a power converter according to a third embodiment of the present invention. FIG. 13 is a diagram illustrating a configuration example of a noise filter circuit provided in a power conversion device according to a fourth embodiment of the present invention. FIG. 5 is a diagram showing an example of a circuit element for induced current bypass shown in FIG. 4. FIG. 9 is a diagram for explaining a cause of deterioration of filter characteristics due to undesired electromagnetic coupling. The figure for demonstrating the reduction effect by the bypass capacitor of the noise resulting from linkage magnetic flux. The figure which shows the example of mounting of the bypass capacitor in the immediate vicinity of the terminal block. FIG. 4 is a diagram illustrating an example of a noise filter circuit provided with a fuse. The figure which shows the conventional general component mounting example of the filter circuit board provided with the fuse.

  Hereinafter, a power converter according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 shows a noise filter circuit having a characteristic configuration in the power converter according to the first embodiment of the present invention. FIG. 1A shows a filter circuit board 6 on which a noise filter circuit 1 and a fuse 7 are mounted. FIG. 3 is a diagram showing a component mounting mode in FIG. Here, the same parts as those of the conventional circuit components shown in FIGS.

As shown in FIGS. 1A and 1B, the filter circuit board 6 according to this embodiment is configured such that the power line 2 is connected from the outside of the metal housing 10 to the filter circuit board 6 in order from the terminal block 4 side. the line capacitor C _X1 constituting part of the noise filter circuit _1, the discharge resistor R _X1 for the line between the capacitor C _X1, the fuse 7, and the remainder of the noise filter circuit 1, except for the line-to-line capacitor C _X1 It is characterized in that the constituent components of the filter are arranged in one direction. The filter components constituting the remaining part of the noise filter circuit 1 except for the line capacitor C _X1 specifically include a reactor L and a line capacitor C _X2 .

Incidentally, the line capacitor C _X1 is mounted in the immediate vicinity of the terminal block 4, whereby the length of the power line 2 between the terminal block 4 and the line capacitor C _X1 is set as short as possible. Here, the filter circuit board 6 is provided near and along the wall surface of the metal casing 10 of the power converter. For example, a wiring pattern of the power line 2 on which the fuse 7 is interposed, for example, on the positive electrodes P1 and P2 side is provided along one side of the filter circuit board 6 close to the wall surface of the metal housing 10.

  Incidentally, the wiring pattern on the negative electrodes N1 and N2 side of the power line 2 is formed at the center of the filter circuit board 6. The wiring pattern of the ground line E of the power line 2 is formed along the other side of the filter circuit board 6 with the wiring patterns on the negative electrodes N1 and N2 side therebetween. Then, the wiring pattern of the ground line E is connected to the metal housing 10 so that the metal housing 10 and the filter circuit board 6 have the same ground potential.

According to such a component arrangement configuration of the filter circuit board 6, the induction current B generated by the flux linkage A to the fuse 7 is bypassed by the line capacitor C _{X <} b> 1, and inside the filter circuit board 6. Can be refluxed. Therefore, it is possible to effectively reduce the outflow of the induced current B due to the linkage magnetic flux A to the outside of the device, and to reduce the noise level flowing out of the device. In addition, when the fuse 7 is blown, the electric charge accumulated in the line capacitor C _X1 is discharged via the discharge resistor R _X1 , so that the electric shock due to the electric charge accumulated in the line capacitor C _X1 is surely prevented. Can be prevented.

  Further, according to the configuration of the filter circuit board 6, a wiring pattern on the positive electrodes P1 and P2 side where the fuse 7 is interposed is provided between the wall surface of the metal housing 10 and the wiring pattern of the ground line E. The wiring patterns on the negative electrodes N1 and N2 can be positioned. As a result, the power line formed by the wiring patterns on the positive electrodes P1 and P2 and the wiring patterns on the negative electrodes N1 and N2 is formed by the wall pattern of the metal casing 10 and the wiring pattern of the ground line E provided at the same potential. 2 can be reduced. Therefore, also in this respect, it is possible to reduce the level of noise flowing out of the apparatus.

2A and 2B show a second embodiment of the present invention, the line capacitor C _X1 constituting the noise filter circuit 1 is _replaced with, for example, two line capacitors C _X1 and C _X1 . _X3 , and one line capacitor C _X3 may be provided between the fuse 7 and the reactor L. By doing so, the capacity of the line capacitor C _X1 provided immediately adjacent to the terminal block 4 can be reduced. Therefore, when the fuse 7 is blown, the electric charge accumulated in the line capacitor C _X1 can be quickly discharged by the discharge resistor R _X1 . Therefore, it is possible to more reliably prevent an electric shock due to the electric charge accumulated in the line capacitor C _X1 .

  Also, as shown in FIG. 3 showing a third embodiment of the present invention, it is useful to provide a shield 12 made of, for example, a mesh-like metal body so as to cover the fuse 7 mounted on the filter circuit board 6. is there. The shield 12 has a role of electromagnetically shielding the fuse 7 from the linkage flux A. Incidentally, the shield 12 does not necessarily need to be connected to the metal housing 10 and grounded. However, in consideration of a method of supporting the shield 12, it is desirable to fix the shield 12 to the metal housing 10. Specifically, when the filter circuit board 6 is screwed and fixed to the metal casing 10, the shield 12 may be mounted together with the filter circuit board 6 on the metal casing 10. .

  Thus, according to the filter circuit board 6 having the configuration in which the fuse 7 is magnetically shielded by the shield 12, the outflow of noise to the outside of the device can be reduced more than in the above-described embodiments. Moreover, the noise level flowing out to the outside can be greatly reduced simply and effectively. Therefore, its practical advantages are great.

  It is also useful to connect a current bypass element (Z1) 13 to the fuse 7 in parallel as shown in FIG. Then, the induced current B induced in the fuse 7 by the linkage magnetic flux A via the current bypass element 13 is returned inside the device. Incidentally, as the current bypass element 13, for example, a capacitor as shown in FIG. 5A or a varistor as a surge suppressor as shown in FIG. 5B is used.

Incidentally, the capacitor serving as the current bypass element 13 functions as a bypass path for the induced current B in the same manner as the line capacitor _CX1 described above. However, this capacitor may be damaged by a surge current when the fuse 7 is blown. In this regard, if the varistor is used as the current bypass element 13, the varistor functions as a capacitor during normal operation, and absorbs surge current when the fuse 7 is blown. Therefore, the varistor effectively functions as an element that circulates the noise current inside the device and increases the surge resistance. Therefore, the effects more than the above-described embodiments can be obtained.

  Note that the present invention is not limited to the above embodiments. For example, circuits of various types conventionally proposed for the noise filter circuit 1 can be appropriately adopted. In addition, here, the effect of reducing the electromagnetic noise with respect to the single-phase alternating current has been described as an example, but it goes without saying that the same effect can be achieved with the three-phase alternating current. In addition, it goes without saying that the present invention can be implemented with various modifications without departing from the scope of the invention.

DESCRIPTION OF SYMBOLS 1 Noise filter circuit 2 Power line 3 Bypass capacitor 4 Terminal block 5 Circuit board 6 Filter circuit board 7 Fuse 8 Conductor pattern 10 Metal casing 12 Shield 13 Current bypass element

Claims (6)

A power conversion device main body that switches input power through a semiconductor switching element to generate an output power of a predetermined voltage, and is provided on an input side of the power conversion device main body and is generated in accordance with a switching operation of the power conversion device main body. And a noise filter circuit for reducing the outflow of high frequency noise to the input power supply system.
The noise filter circuit is configured to be mounted on a filter circuit board together with a fuse that is blown at the time of failure and disconnects the power conversion device main body from the input power supply system,
The filter circuit board is a line capacitor which is interposed between input power lines and constitutes a part of the noise filter circuit, from a terminal block side of the filter circuit board to which a power supply line of the input power supply system is connected. A power conversion device comprising: a discharge resistor for a line capacitor, the fuse, and a filter component constituting a remaining portion of the noise filter circuit excluding the line capacitor, arranged in this order. The power converter according to claim 1, wherein the line capacitor is mounted near a terminal block of the filter circuit board to which a power line of the input power system is connected . Providing the filter circuit board near the wall surface of the metal housing of the power converter, along the wall surface ,
The ground line wiring pattern of the filter circuit board is connected to the metal casing, and the positive and negative wiring patterns of the power lines of the filter circuit board are connected to the side surfaces of the metal casing and the ground line wiring pattern. The power converter according to claim 1, wherein the power converter is provided so as to be positioned therebetween.   4. The fuse according to claim 1, wherein the fuse is mounted on the filter circuit board while being shielded from a conductive layer forming a wiring pattern formed on the filter circuit board by a shielding member provided near the fuse. The power converter according to claim 1.   4. The power converter according to claim 1, wherein the fuse is mounted on the filter circuit board by connecting a circuit element for induced current bypass in parallel with the fuse. 5.   The power conversion device according to claim 5, wherein the circuit element for inductive current bypass includes a capacitor or a varistor for absorbing surge.

Images