JP5097791B2 - Power converter - Google Patents

Description

  The present invention relates to a technique for providing a power conversion device.

  Regarding the internal wiring of the power converter, it is known that the wiring connecting the smoothing capacitor and the reverse converter must reduce the inductance in order to suppress the overvoltage of the reverse converter and protect the semiconductor element. It has been.

  A method for reducing this inductance is disclosed in Patent Document 1.

  In Patent Document 1, “the first, second, and third DC voltage wiring portions (20) are connected to the first, second, and third plate conductors (201 to 203) and the first and second insulations. The sheet (204, 205) has a structure in which the sheets are alternately laminated, and thus a laminated structure in which the plate-like conductors are sandwiched by the insulating sheets in this manner allows three or more DC voltages and AC voltages to be obtained. It is also described that the wiring inductance can be reduced even in a device that converts the voltage. "

JP-A-11-89247

  As described in Patent Document 1, in the power conversion device, when the element of the reverse conversion unit is turned off, the energy stored in the inductance of the wiring connecting the smoothing capacitor and the reverse conversion unit is used. When the semiconductor element is cut off, a steep overvoltage (bounce voltage) is generated across the device as shown in FIG.

  Bypassing this cutoff energy, a circuit that suppresses overvoltage (bounce voltage) and protects the element is called a snubber circuit. This circuit protects the semiconductor element by suppressing the overvoltage (bounce voltage) that occurs at the time of turn-off of the element in the reverse conversion unit. It is generally performed to provide for this purpose.

  However, in order to suppress a steep and large overvoltage (bounce voltage), an RC snubber circuit with a simple circuit configuration requires a large capacitor, and in order to reduce the capacitor, a charge / discharge RCD snubber circuit, It is necessary to provide a discharge prevention type RCD snubber circuit. In either case, a space for installing the circuit is required, and it is necessary to consider the wiring of the snubber circuit.

  Moreover, in order to prevent this overvoltage (bounce voltage), in addition to suppressing with a snubber circuit, as described in Patent Document 1, the inductance of the wiring conductor plate connecting the smoothing capacitor and the inverse conversion unit should be reduced. This prevents energy from being stored and prevents overvoltage (bounce voltage) from occurring.

  In reducing the inductance of the above-described wiring conductor plate, the degree of reduction is expected to change depending on how each wiring conductor plate is provided.

  Therefore, it is an object to improve the degree of reduction of inductance by devising the way of providing.

  The present invention solves the above problems as follows.

A forward conversion unit that converts electric power from a power source into direct current power; a smoothing unit in which a first capacitor unit and a second capacitor unit that smooth the output from the forward conversion unit are connected in series; and the smoothing unit And an inverse conversion unit that converts the output of AC to AC power and outputs the AC power, and the positive electrode terminal and the negative electrode terminal of the first capacitor unit and the positive electrode terminal and the negative electrode terminal of the second capacitor unit are adjacent to each other. A first wiring conductor plate that is arranged so that the terminals have different polarities, and connects the positive terminal of the first capacitor unit and the P phase of the inverse conversion unit; and the negative terminal of the second capacitor unit And a second wiring conductor plate that connects the N phase of the inverse conversion unit, a third wiring conductor plate that connects the negative terminal of the first capacitor unit and the positive terminal of the second capacitor unit, The first wiring conductor plate and the second wiring The conductor plate includes an extended surface extended to a position corresponding to a region including at least a part of a line connecting the negative electrode terminal of the first capacitor unit and the positive electrode terminal of the second capacitor unit. The wiring conductor plate includes an extended surface extended to a position corresponding to a region including at least a part of a line connecting the positive electrode terminal of the first capacitor unit and the negative electrode terminal of the second capacitor unit, The first wiring conductor plate includes a surface extended to a region corresponding to the second wiring conductor plate, the first wiring conductor plate, the second wiring conductor plate, and the third wiring conductor plate, Is a power conversion device in which at least a part of the region has three layers.

ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the power converter device which improved reliability rather than before.
Since overvoltage generated at turn-off of the elements of the reverse conversion unit can be suppressed, the snubber circuit of the power conversion device can be simplified and miniaturized, and the heat generation of the reverse conversion unit can be reduced, so that the device can be made smaller and better than before. New products can be supplied.

It is an example of the jump voltage at the time of turn-off. It is an Example of this invention. It is an example of the simulation result of the Example of this invention. It is an example of the circuit diagram of a power converter device. It is another Example of this invention. It is another Example of this invention and a simulation result. It is another Example of this invention. It is an Example of this invention and a simulation result.

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

  FIG. 4 is an example of a circuit diagram of the power converter. In this figure, AC power from a power source is converted into DC power by a forward conversion (converter) unit 1 and then input to a smoothing capacitor 2 for smoothing. The output of the smoothing capacitor 2 is supplied from a control unit (not shown). It is converted into AC power by the reverse conversion (inverter) unit 3 under the control of the control signal.

  As an example, the capacitor 2 used in the smoothing circuit of the power converter is an aluminum electrolytic capacitor. For example, in a power converter for a 400V input voltage, the working voltage of a general aluminum electrolytic capacitor is 400V. For this reason, when the voltage of the input power supply is 400V, two smoothing capacitors 2 are used for the working voltage of the smoothing capacitor 2, and the + (positive electrode) terminal of the smoothing capacitor C1 and the-(negative electrode) terminal of the smoothing capacitor C2. Are generally used by connecting them in series and using two smoothing capacitors with a withstand voltage of 800 V (400 V + 400 V). At this time, a phase in which the positive electrode terminal of the smoothing capacitor C1 and the negative electrode terminal of the smoothing capacitor C2 are connected is referred to as an M phase.

  With respect to the embodiment in which the smoothing capacitor C1 and the smoothing capacitor C2 in FIG. 4 are connected in series, a method of providing a wiring conductor plate (hereinafter referred to as a bus bar) and current in that case will be described with reference to FIGS. How to flow will be described.

  In FIG. 2, the smoothing capacitors 4a and 4b are provided with positive terminals 5a and 5b and negative terminals 6a and 6b. At that time, the positive and negative electrodes of the two smoothing capacitors are arranged so as to have different polarities. Specifically, the negative electrode terminal 6b of the smoothing capacitor 4b is located next to the positive electrode terminal 5a of the smoothing capacitor 4a. Further, the positive electrode terminal 5b of the smoothing capacitor 4b is located next to the negative electrode terminal 6a of the smoothing capacitor 4a. In addition, it is necessary to avoid an arrangement error in the operation of arranging the positive and negative electrodes of the smoothing capacitors 4a and 4b to have different polarities. In FIG. 2, the attachment member connecting the smoothing capacitors 4 a and 4 b is illustrated, and the above-described arrangement work is avoided by the shape of the attachment member and the positions of the attachment holes provided in the member. Is possible.

  Then, there are a P-phase bus bar 7 connected to the positive electrode terminal 5b and the P phase on the positive side of the reverse conversion part, and an N phase bus bar 8 connected to the negative electrode terminal 6a and the N phase on the negative side of the reverse conversion part.

  Further, in order to connect the smoothing capacitor 4a and the smoothing capacitor 4b in series, the M-phase bus bar 9 is provided so as to connect the positive electrode terminal 5a of the smoothing capacitor 4a and the negative electrode terminal 6b of the smoothing capacitor 4b. An insulator 10 is also provided to insulate the P-phase bus bar 7 from the N-phase bus bar 8.

  FIG. 3 shows current flow lines obtained as a result of a simulation of the flow of current flowing on the surface of the bus bar during this arrangement. FIG. 3 shows that the current flows uniformly on the surface of the bus bar.

  As described above, in FIGS. 2 and 3, the positive and negative electrodes of the two smoothing capacitors are devised so as to be different from each other. Since the different polarities are arranged next to each other in this way, it is possible to provide an overlapping portion between the P-phase bus bar 7 connected to the positive terminal 5b and the N-phase bus bar 8 connected to the negative terminal 6a. Thus, the distance between the two can be made a small distance so as to face each other. The insulation distance between the bus bars is reduced and the insulator 10 is sandwiched.

  Next, another embodiment of the present invention will be described with reference to FIG.

  In the embodiment shown in FIG. 2, the P-phase bus bar 7 and the N-phase bus bar 8 overlap each other. However, in FIG. 7, the M-phase bus bar 9 also overlaps with the P-phase bus bar 7 and the N-phase bus bar 8. It is devised to provide a part. In this way, the inductance is reduced more than in FIG.

  As shown in FIG. 7, the smoothing capacitors 4a and 4b are provided with positive terminals 5a and 5b and negative terminals 6a and 6b. A P-phase bus bar 7 is connected to the positive terminals 5a and 5b, and an N-phase bus bar 8 is connected to the negative terminals 6a and 6b. The M-phase bus bar 9 is connected to the positive electrode terminal 5a of the smoothing capacitor 4a and the negative electrode terminal 6b of the smoothing capacitor 4b. An insulator 10 is provided between P-phase bus bar 7 or N-phase bus bar 8 and M-phase bus bar 9.

  In order to connect the smoothing capacitors 4a and 4b in series, an M-phase bus bar 9 is used, one connected to the positive terminal 5a of the smoothing capacitor 4a and the other connected to the negative terminal 6b of another smoothing capacitor 4b. Further, the shape of the wiring conductor plates of the bus bar connecting the forward conversion unit 1 and the reverse conversion unit 3 and the N-phase bus bar 8 is increased.

  The shape of the wiring conductor plate of the M-phase bus bar 9 is increased in the same manner as the P-phase bus bar 7 and the N-phase bus bar 8, and the M-phase bus bar 9 is overlaid on the P-phase bus bar 7 and the N-phase bus bar 8. And each is arranged so that the area which overlaps each other may become large, and also each is made to face at a short distance interval. For this purpose, the insulator 10 is sandwiched between the bus bars in order to reduce the insulation distance.

  FIG. 5 and FIG. 6 show the simulation results of the arrangement, shape, and current flow lines of each wiring conductor plate.

  As shown in FIG. 5, the M-phase bus bar 9h is expanded in a plane so as to overlap with the P-phase bus bar 7h and the N-phase bus bar 8h in addition to the shape in which the positive electrode terminal 5a and the negative electrode terminal 6b are connected in the shortest time. An extended surface is provided.

  Furthermore, each of the P-phase bus bar 7h and the N-phase bus bar 8h is also provided with an expansion surface that is expanded and expanded so as to overlap with the other two bus bars.

  In the simulation of FIG. 6, the current flow line of the N-phase bus bar 8h flows facing the M-phase bus bar 9h in addition to the current flow that connects the positive electrode terminal 6a and the negative electrode terminal connected to the inverse conversion unit in the shortest time. It is shown that such a current flows through the expansion surface.

  In this simulation, it was confirmed that the current flow expanded and detoured on the expanded surfaces provided in the three bus bars of the P-phase bus bar 7h, the N-phase bus bar 8h, and the M-phase bus bar 9h. This is a result contrary to the expectation that the current flows through the shortest current path between the two terminals at the start and end when the current is passed. However, it has become possible to obtain support for reducing the mutual inductance by providing the above-described expansion surface so as to utilize this result.

Further, in FIG. 5, the M-phase bus bar 9h is provided above and below so as to sandwich the P-phase bus bar 7h and the N-phase bus bar 8h, and the directions of currents are opposite to each other including the expansion surface. In this way, the inductance can be reduced.
Specifically, as shown in FIG. 5, the P-phase bus bar 7 h has a current flow that is opposite to the M-phase bus bar 9 h. Similarly, with respect to the M-phase bus bar 9h, the N-phase bus bar 8h has a current flow that is opposite to each other.

  However, the order of the bus bars described above is not limited to the above, and the order may be appropriately changed according to the mounting state. Although it is assumed that all current directions are not opposite to each other as shown in FIG. 5, if at least one set of bus bars flows in opposite directions, the inductance can be reduced. It can be said that it is preferable.

The distance between the stacked bus bars is particularly small and the short distance is more effective. However, according to the standards such as UL508C, EN61800-5, EN51870, etc., when the following insulating material is used, the thickness of the material is 0. It cannot fall below 71 mm (0.028 inch). Insulating materials in this case are Dially Phthalate, Epoxy, Melamine, Melamine-Phenolic, Phenolic, Unfilled Nylon, Unfilled Polycarbonate, Urea Formata.
ldehide, Cambric, Electric Grade Paper, RTV, Silicone, Treated Close, and Vulcanized Fiber.

  Furthermore, in the case of using the following insulating material, the thickness of the material cannot fall below 0.25 mm (0.010 inch). The insulating material in this case is Aramid Paper.

  Furthermore, when the following insulating material is used, the thickness of the material cannot fall below 0.15 mm (0.006 inch). The insulating material in this case is Mica.

  Furthermore, when the following insulating material is used, the thickness of the material cannot be less than 0.18 mm (0.007 inch). The insulating material in this case is Mylar (PETP).

  Further, when using a material other than these, the thickness of the material is 0.71 mm (0.028 inch) or more, and further, a pressure resistance test of 5000 VAC is performed, and it is determined that there is a pressure resistance, and more than a specified relative thermal index. (RTI), hot wire ignition (HWI), high-current arc resistance to ignition (HAI), and comparative tracking index (CTI).

  For this reason, for example, when the bus bar is insert-molded into a module, etc., and integrally molded with the insulator, the thickness of the insulator is sufficient in order to satisfy these regulations and create a shape by the injection molding method. About 2 to 3 mm is required.

  Furthermore, even when a sheet-like insulator is used, considering the tolerance in manufacturing the bus bar, the distance between the bus bars can be about 1 to 3 mm even if the thickness of the insulator sheet can be reduced. Is common.

  However, if it is this distance, there is no problem in empirical theory and an effect can be obtained.

  Moreover, the simulation result of another Example is shown in FIG. It can be confirmed that the current flow lines on each bus bar are in line with the current flows of the other phases.

  6 and FIG. 8 shows the difference between the simulation results in FIG. 6 when the M-phase bus bar is installed between the P-phase and the N-phase, and FIG. 8 shows the M-phase bus bar between the P-phase and the N-phase. The case where it is installed on the phase is shown. From this result, even when the M-phase bus bars are arranged in the middle or upper side of the P-phase or N-phase, they have overlapping areas, so that they are arranged to face each other at a short distance. It can be seen that substantially the same effect can be obtained in terms of inductance reduction.

  6 and 7, the portion connected to the P phase on the positive side of the reverse conversion unit and the portion connected to the N phase on the negative side of the reverse conversion unit are provided at positions facing the back of the drawing. However, it is not limited to this, and can be changed as appropriate. For example, in a position approaching the near side opposite to the back side in the drawings of FIGS. 6 and 7, the portion connected to the P phase on the positive side of the reverse conversion unit, or the N phase on the negative side of the reverse conversion unit A portion to be connected may be provided. Although not illustrated in the figure, it was confirmed by simulation that the inductance is reduced even in the configuration.

  According to the above-described embodiment based on the present invention, the overvoltage generated at the time of turn-off of the element of the reverse conversion unit can be suppressed. Therefore, the snubber circuit of the power conversion device can be simplified and miniaturized, and the heat generation of the reverse conversion unit can be reduced. Therefore, the apparatus can be made smaller than before, and a good product can be supplied.

1: forward conversion (converter) part, 2: smoothing capacitor,
3: reverse conversion (inverter) section, 4: smoothing capacitor, 5: positive terminal of smoothing capacitor, 6: negative terminal of smoothing capacitor, 7: P-phase bus bar, 8: N-phase bus bar, 9: M-phase bus bar, 10: Insulator.

Claims (5)

A forward converter that converts power from the power source into DC power;
A smoothing unit in which a first capacitor unit and a second capacitor unit that smooth the output from the forward conversion unit are connected in series;
An inverse conversion unit that converts the output of the smoothing unit into AC power and outputs the AC power, and
The positive terminal and the negative terminal of the first capacitor part and the positive terminal and the negative terminal of the second capacitor part are arranged so that adjacent terminals are different from each other,
A first wiring conductor plate connecting the positive terminal of the first capacitor part and the P phase of the inverse conversion part;
A second wiring conductor plate connecting the negative electrode terminal of the second capacitor unit and the N phase of the inverse conversion unit;
A third wiring conductor plate for connecting the negative terminal of the first capacitor part and the positive terminal of the second capacitor part;
The first wiring conductor plate and the second wiring conductor plate correspond to a region including at least a part of a line connecting the negative terminal of the first capacitor unit and the positive terminal of the second capacitor unit. With an expanded surface that extends to the position
The third wiring conductor plate has an extended surface extended to a position corresponding to a region including at least a part of a line connecting the positive electrode terminal of the first capacitor unit and the negative electrode terminal of the second capacitor unit. Prepared,
The first wiring conductor plate includes a surface extended to a region corresponding to the second wiring conductor plate,
Wherein a first of the third wiring planar conductor and the wiring conductor plate wherein a second wiring planar conductor, the power converter that has at least a partial region becomes three layers. The power conversion device according to claim 1,
The power converter according to claim 1, wherein the direction of the current flowing through the second wiring conductor plate is opposite to the direction of the current flowing through the first wiring conductor plate or the third wiring conductor plate. The power conversion device according to claim 1,
Wherein the first power converter and the second wiring planar conductor is characterized by Rukoto provided between the wiring conductor plate and the third wiring planar conductor. The power conversion device according to claim 1,
The first power conversion device wherein the third wiring planar conductor is characterized by Rukoto provided between the wiring conductor plate second wiring planar conductor. The power conversion device according to claim 1,
Power converter of the first wiring planar conductor is characterized by Rukoto provided between said second wiring conductor plate and the third wiring planar conductor.

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