JP4968528B2 - 3-level power converter - Google Patents

Description

  The present invention mainly relates to a three-level power converter having an improved filter capacitor wiring structure.

For example, in the electric vehicle field, a three-level power converter is widely applied as a large-capacity power converter for DC-fed trains and AC-fed trains.
FIG. 10 shows a main circuit configuration of a recent representative AC train. In the figure, PT is a pantograph, HB is a high-speed circuit breaker, MTr is a main transformer, wg ₁₁ is a primary winding, and wg ₂₁ , wg ₂₂ , and wg ₂₃ are secondary windings.

The power conversion device includes a converter Conv connected to the secondary winding wg ₂₁ and a three-phase three-level inverter Inv. The converter Conv converts the single-phase voltage of the secondary winding wg ₂₁ into a DC voltage, converts the DC voltage into a three-phase AC voltage by an inverter Inv as a VVVF (variable voltage variable frequency) inverter, and is used for driving a train. AC power of variable voltage and variable frequency is supplied to the induction motor IM.
Incidentally, in FIG. 10, Q is a switching element such as IGBT, _{D C} is the coupling diodes, _{C F} is the filter capacitor, _{E P} is the DC positive supply voltage, _{E C} is the neutral point voltage, _{E N} is the negative supply voltage Indicates.

As for the inverter which comprises this kind of power converter device, as described in patent documents 1, for example, the circuit for one phase is put together in one unit structure.
That is, in the case of a three-phase inverter, a method of configuring one inverter with three units is adopted. Therefore, filter capacitor C _F, as shown in FIG. 10 is also provided in a different unit respectively divided into each phase.

Furthermore, Patent Document 2 is an example in which a circuit for one phase of a three-level power converter is configured as one unit.
In this prior art, an IGBT module, a clamp diode (diode module), a snubber resistor, etc. are mounted on a heat receiving member of a cooling body, and a structure in which a filter capacitor is disposed at a position separated from the heat receiving member by a support frame is adopted. Yes.

  Here, if the filter capacitor of each phase is separated from the switching element, the wiring length between the switching circuit constituted by the IGBT module and the clamp diode and the filter capacitor is increased, and the inductance is increased, and the three-level power conversion There is a problem that the switching surge voltage generated at the time of commutation of the device becomes large.

Therefore, Patent Document 3 discloses a conventional technique for reducing the inductance by shortening the wiring length between the switching element and the bipolar terminals of the filter capacitor.
However, this prior art is exclusively intended for a two-level power converter, that is, a power converter equipped with a positive and negative DC power supply, and the shunt current of the commutation current between the phases in the three-level power converter and the positive arm No mention is made of countermeasures in consideration of the uniformity of the wiring structure of the negative arm.

FIG. 11 is a diagram showing the inverter Inv extracted from FIG.
In FIG. 11, P is a DC positive power supply terminal, C is a neutral power supply terminal, N is a DC negative power supply terminal, U, V, and W are AC output terminals for each phase, Q _U1 , Q _U2 , Q _V1 , and Q _{V2. , Q W1, Q W2, Q} X1, Q X2, Q Y1, Q Y2, Q Z1, Q Z2 is IGBT module corresponding to the switching element Q in FIG. _{10, D U, D V,} D W, D X, D _{Y, D Z} is a coupling diode diode module corresponding to _{D C, C FU, C FX} , C FV, C FY, C FW, C FZ filter capacitors corresponding to the filter capacitor _{C F} of FIG. 10 in FIG. 10 .

Here, _QU1 , _QU2 , _QX1 , _QX2 are U-phase IGBT modules, _QV1 , _QV2 , _QY1 , _QY2 are V-phase IGBT modules, _QW1 , _QW2 , _QZ1 , _QZ2 are W Also referred to as a phase IGBT module, D _U and D _X are also referred to as U-phase diode modules, D _V and _DY are also referred to as V-phase diode modules, and D _W and D _Z are also referred to as W-phase diode modules. C _FU and C _FX are also called U-phase filter capacitors, C _FV and C _FY are also called V-phase filter capacitors, and C _FW and C _FZ are also called W-phase filter capacitors.

Further, the _{M U} in FIG. 11 U-phase three-level converter, the _{M V} V-phase three-level converter, the _{M W} of W-phase three-level converter circuit. Also, it will be referred to arms of the positive supply voltage E _P side relative to the neutral point voltage E _C is referred to as a positive side arm, a negative-side arm arms of the negative power supply voltage E _N side.

The IGBT module _{Q U1 ~Q X2, Q V1 ~Q} Y2, Q W1 ~Q Z2 , as AC output terminals U, V, the voltage of the W is a sine wave voltage of three-phase PWM controlled, positive power supply voltage E _P, select the three values of the neutral point voltage E _C and the negative power supply voltage E _N, it is switched with a phase difference of 120 degrees between each phase. In this case, a commutation current flows through the IGBT module, the diode module, and the filter capacitor at the time of switching for selecting three values of the output voltage in the U phase, the V phase, and the W phase.
In order to minimize the inductance of the commutation current path, that is, the inductance of the commutation circuit and the surge voltage generated by the commutation current, the arrangement of the IGBT module, the diode module, and the filter capacitor and the wiring therebetween And a design that minimizes the inductance must be made.

  Here, FIG. 12 shows the U-phase commutation circuit in FIG. The V phase and the W phase are also explained by the same commutation circuit.

FIG. 12A shows a case where the IGBT module _QU1 is switched from on to off when the output current _IU is positive, that is, when the current is flowing from the AC output terminal U toward the load, or Q a commutation circuit formed when _U1 off → diode module D _U with the on switching off, i, ii indicates the path of commutation current.
At this time, the Q _U1 or D _U, surge voltage caused by the inductance of the circuit occurs.

FIG. 12B shows a case where the IGBT module _QX2 is switched from on to off when the output current _IU is negative, that is, when current flows from the load toward the AC output terminal U, or , Q _X2 is a commutation circuit formed when the diode module D _X is turned off in accordance with switching from OFF to ON, and iii and iv indicate paths of the commutation current.
At this time, a surge voltage due to the inductance of the circuit is generated in Q _X2 or D _X.

The surge voltage generated with the switching operation is caused by the inductance of the circuit as described above and causes the module element to be destroyed. Therefore, it is necessary to reduce the surge voltage. In order to reduce the inductance of the circuit that causes this, the wiring length between the IGBT module, the diode module, and the filter capacitor existing in the paths i to iv must be reduced.
Further, when looking at the route i and the route iii and the route ii and the route iv, the lines (neutral point voltage E _C lines) to which the neutral point power supply terminals C are connected are symmetric with respect to the center line. In order to minimize the inductance deviation of the commutation circuit of the positive and negative arms, the IGBT module, the diode module, the filter capacitor, and the power supply terminals P, C, N, and the AC output terminals U, V, W on each path It is desirable that the arrangement of wiring members and the like is symmetrical in a geometric sense.

In the three-level power converter, Patent Literature 4 and Patent Literature 5 disclose an element arrangement for minimizing the wiring inductance and a wiring method between the element terminals.
Among these, in the three-level power conversion device according to Patent Document 4, the switching elements, the coupling diodes, and the DC voltage source are arranged on a substantially straight line in both the positive side arm and the negative side arm. These connection portions are projected in the same direction, and a predetermined connection between the connection portions is made by using a plurality of flat wiring boards orthogonal to the direction and insulated from each other.

  In addition, the three-level power conversion device according to Patent Document 5 includes a plurality of switching elements, coupling diodes, a DC voltage source (smoothing capacitor), and a flat plate shape disposed so as to be sandwiched between the switching elements and the DC voltage source. The switching element and the coupling diode are arranged in a line, and the DC voltage source and the coupling diode are connected to each other through the front and back of substantially the same portion of the flat conductor. Further, in this three-level power converter, wiring between the first current path through which the current of the switching element to be turned off flows and the second current path in which the current increases as the current in the first current path decreases is provided. It is configured to follow.

Japanese Patent No. 2896454 (paragraphs [0045] to [0048], FIGS. 3 to 5 etc.) Japanese Patent No. 3367411 (paragraphs [0016] to [0019], FIGS. 1 to 4 etc.) Japanese Unexamined Patent Publication No. 2000-069766 (paragraphs [0023] to [0025], FIG. 1, FIG. 2, FIG. 5, FIG. 6 etc.) Japanese Patent No. 3229931 (paragraphs [0019] to [0026], FIGS. 7 to 10 etc.) Japanese Patent No. 3637276 (paragraphs [0018] to [0032], FIGS. 1 to 7 etc.)

When each phase circuit constituting a power conversion device such as an inverter is configured as a separate unit as in Patent Document 1, a common voltage conductor on the circuit is required for each unit, and the overall size of the device is large. Cause an increase in weight and weight.
Also in Patent Document 2, there is a problem that the inductance caused by the wiring length between the switching element and the filter capacitor becomes large. This inductance generates a large surge voltage with the switching operation and causes damage to the element. However, if a snubber circuit is added to absorb the surge voltage, the inverter or converter unit becomes larger due to the components of the snubber circuit. As a result, the entire apparatus becomes large, which causes an increase in weight.

  Further, according to the prior art described in Patent Documents 4 and 5, the wiring inductance can be reduced to some extent, but from the viewpoint of miniaturization of the device, the wiring structure of the filter capacitor, the bipolar terminal, the DC power supply terminal There is room for further improvement in terms of layout.

Therefore, the problem to be solved by the present invention is:
(1) Lower inductance of the wiring around the switching element including the filter capacitor (2) Rationalization of the wiring structure of the filter capacitor (reduction of the number of parts, sharing of parts, etc.)
(3) To provide a three-level power conversion device in which the DC terminal of each phase and the bipolar terminals of the filter capacitor are rationally arranged to reduce the size and weight of the entire device.

  In order to solve the above-mentioned problems, the present invention provides a bipolar terminal of a filter capacitor for minimizing the wiring inductance of each phase in a three-level power conversion device including a plurality of three-phase conversion circuits and a plurality of filter capacitors. Is basically connected to a DC terminal by an overlapping wiring structure of two flat conductors.

That is, the main features of the present invention in the three-level power converter such as the three-level inverter shown in FIG. 11 are as follows.
First, the two pole terminals of the filter capacitors C _FU , C _FV , C _FW of the positive arm of each phase are collectively connected to the DC positive power supply terminal P and the neutral point power supply terminal C for all phases. The flat conductors are respectively connected to the flat conductors, and the flat conductors are laminated via an insulating plate (a laminated wiring structure of two flat conductors is also referred to as a stacked wiring). Similarly, the two flat conductors connected to the neutral point power supply terminal C and the DC negative power supply terminal N are collectively connected to the negative electrode filter capacitors C _FX , C _FY , and C _FZ for all phases. Are connected to each other, and these flat conductors are laminated and disposed via an insulating plate.

Further, IGBT modules Q _U1 , Q _U2 , Q as switching element modules constituting the positive side arm and the negative side arm so that the wiring inductances of the positive side arm and the negative side arm are balanced and become the minimum value in each phase. _{V1, Q V2, Q W1,} Q W2, Q X1, Q X2, Q Y1, Q Y2, Q Z1, Q Z2 and diode modules _{D U, D V, D W} , D X, D Y, and _{D Z,} One point of the conductor corresponding to the neutral point voltage E _C is arranged so as to be substantially symmetric with respect to the geometric center point, and the wiring member is also arranged so as to be substantially symmetric with respect to the geometric center point.
Further, the power supply terminals of the filter capacitors connected to the DC positive power supply terminal P, the neutral point power supply terminal C, and the DC negative power supply terminal N are symmetric with respect to the geometric center point in each phase. The AC output terminals U, V, W of each phase are arranged on a straight line including the geometric center point.

Further, for the power supply terminals P, C, N and the AC output terminals U, V, W, overlapping wiring by a flat conductor of filter capacitors C _FU , C _FV , C _FW , C _FX , C _FY , C _FZ and external terminals Appropriate positioning is performed in order to achieve overlapping wiring with a wide conductor of wiring.

Laminated wiring portion for connecting the elements of each phase of the three-level converter circuit M _U, M _V, M _W is the side opposite to the element group such as a switching element at an intermediate portion between the positive side arm and the negative-side arm Has a protruding part. On the surface of the convex portion, three-level converter circuit M _U, M _V, the power supply terminal P of M _W, C, each power terminal of the filter capacitor connected respectively to N, also on the back AC output terminal U , V, W are arranged at symmetrical positions with a specific point on the intermediate line between the positive side arm and the negative side arm as a center point.

Each phase of a three-level converter circuit M _U, M _V, uniform commutation currents generated upon commutation of the switching elements constituting the M _W is, the commutation current is prevented from shunting each other between phases with each phase In order to achieve this, a notch for suppressing the shunt current is provided at a predetermined position of the flat conductor between the filter capacitors of adjacent phases.

In the case where one filter capacitor is configured for each arm, the arrangement direction of the bipolar terminals of each filter capacitor is made parallel to the surface of the multilayer wiring portion.
When the filter capacitor is composed of a plurality of capacitor units per arm, the arrangement direction of the bipolar terminals of each capacitor unit is made perpendicular to the surface of the multilayer wiring portion. Furthermore, it arrange | positions so that the polarity of the bipolar terminal of an adjacent capacitor | condenser unit may change alternately.

  Normally, in the case of a three-phase inverter, since at least one filter capacitor is installed for each arm, the minimum number of wires from the power terminals P, C, N to the filter capacitor is required per phase. A minimum of 9 is required. Even in the case of a two-phase converter, the minimum number of wires from the power terminals P, C, N to the filter capacitor is three per phase, and the minimum is six for two phases.

  On the other hand, according to the present invention, since the wiring is formed by the flat conductors collectively from the power terminals P, C, N, the inductance of the wiring is reduced. Furthermore, the number of wires from the power terminals P, C, N to the filter capacitor is 4 for the positive arm and 2 for the negative arm regardless of the number of phases of the inverter, etc. Reduction and standardization of parts are possible, simplifying wiring, reducing assembly man-hours, making the device compact, compact, and lightweight.

All phase switching elements, coupling diodes, power supply terminals, AC output terminals, etc. are arranged symmetrically around the geometric center point, and the same applies to the positive and negative arm filter capacitors. Therefore, the inductance of the commutation loop can be minimized and made uniform.
Therefore, the switching element of each arm can be switched with a sufficiently small surge voltage without adding a snubber circuit. Furthermore, the two-layer flat plate conductor and the insulating plate sandwiched between them have the same shape and the same structure in both arms, and thus are effective in sharing parts and reducing the number of parts.

  The power supply terminals and AC output terminals of each phase are provided at the most effective positions for the wiring of the DC voltage and the wiring of the AC voltage with the wide flat conductors, so that the wiring inductance of the power supply and the AC output is reduced. Inductive interference to nearby electronic circuits can be reduced.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, the present invention is applied to a three-phase three-level inverter.
First, FIG. 1 is a wiring diagram for explaining a filter capacitor arrangement structure and connection state for minimizing the inductance of the commutation circuit shown in FIG. 12 for each phase of a three-phase three-level inverter. .

In FIG. 1, reference numerals 1, 2, and 3 denote U-phase, V-phase, and W-phase three-level conversion circuits, which correspond to the phase-three level conversion circuits M _U , M _V , and M _W in FIG. Each of the three-level conversion circuits 1 to 3 includes U-phase, V-phase, and W-phase IGBT modules 11 to 14, 21 to 24, and 31 to 34, U-phase, V-phase, and W-phase diode modules 15, 16, 25, 26, 35, 36.

Reference numeral 4 denotes a positive side arm filter capacitor connection circuit, which is a positive side arm U, V, W phase filter capacitor 41, 42, 43, and two positive side arm filter capacitor connection flat plate conductors 101 connecting them in parallel. , 102. The flat conductor 101 is also referred to as a positive power supply flat conductor, and 102 is also referred to as a neutral power supply flat conductor. The filter capacitor 41, 42, filter capacitor _C FU in FIG _11, C _FV, corresponding to _{C FW.}
The plate conductor 101 is provided with U, V, W phase filter capacitor DC power supply terminals 111, 211, 311. The plate conductor 102 is provided with U, V, W phase filter capacitor DC power supply terminals 112, 212, 312. Is provided.

On the other hand, reference numeral 5 denotes a negative arm filter capacitor connection circuit, which is a negative arm U, V, W phase filter capacitor 51, 52, 53, and two negative arm filter capacitor connection plates connecting them in parallel. It consists of conductors 103 and 104. The flat conductor 103 is also referred to as a neutral power supply flat conductor, and 104 is also referred to as a negative power supply flat conductor. The filter capacitors 51, 52, and 53 correspond to the filter capacitors C _FX , C _FY , and C _FZ in FIG.
The flat conductor 103 is provided with U, V and W phase filter capacitor DC power supply terminals 113, 213 and 313, and the flat conductor 104 is provided with U, V and W phase filter capacitor DC power supply terminals 114, 214 and 314. Is provided.

Here, the U, V, and W phase filter capacitor DC power supply terminals 111, 211, and 311 are connected to the DC positive power supply terminal P through a conductor on a laminated wiring portion 503 described later, and the U, V, and W phase filter capacitors are connected. The DC power supply terminals 114, 214, and 314 are also connected to the DC negative power supply terminal N. At the same time, the DC power supply terminals 111, 211, 311 are connected to the collectors of the IGBT modules 11, 21, 31, and the DC power supply terminals 114, 214, 314 are also connected to the emitters of the IGBT modules 14, 24, 34.
The U, V, and W phase filter capacitor DC power supply terminals 112, 212, 312, 113, 213, and 313 are connected to a neutral point power supply terminal C through a conductor on a laminated wiring portion 503 described later.
Furthermore, the connection points between the positive side arm and the negative side arm of each phase three-level conversion circuit 1, 2, 3 are U, V, W phase AC output terminals 115, 215, 315.

Next, FIG. 2 is a structural diagram of a power unit of a three-level inverter corresponding to the wiring diagram of FIG. 1, FIG. 2 (a) is a front view, and FIG. 2 (b) is a right side view of FIG. It is.
In FIG. 2A, CL _U , CL _V , and CL _W are U, V, W phase filter capacitors 41, 42, 43 for the positive side arm, U, V, W phase filter capacitors 51, 42 for the negative side arm, U passing through the center of the 52 and 53, a V, W-phase centerline, CL _C is an intermediate line passing through the midpoint of the positive and negative arms. Further, the flat conductors 101 to 104 and the power terminals 111 to 114, 211 to 214, 311 to 314 of each phase are drawn at positions separated in the vertical direction in order to clearly show the positional relationship between the terminals. It is disposed proximate to the arm intermediate line CL _C. In particular, two flat conductors 101, 102 and 103, 104 are stacked to form a laminated structure.

  In FIG. 2B, 501 is an insulating plate that insulates between the flat conductors 101 and 102, 502 is an insulating plate that insulates between the flat conductors 103 and 104, and 503 is an insulating plate that is sandwiched between the front and back conductors. The formed multilayer wiring portion 504 such as a printed circuit board is mounted with an IGBT module or a diode module (not shown), and the filter capacitors 41 to 43, 51 to 53 or the like via the multilayer wiring portion 503 and the flat conductors 101 to 104 Module mounting portions connected to the power terminals 111 to 114, 211 to 214, 311 to 314 of each phase, and the AC output terminals 115, 215, and 315 of each phase, and 505 are cooling body heat receiving portions for heat dissipation.

  More specifically, the filter capacitors 41, 42, and 43 for the positive side arm and the filter capacitors 51, 52, and 53 for the negative side arm are provided for each arm by two flat plate conductors 101, 102, 103, and 104, respectively. Connected in parallel. Further, the flat conductor 101 is arranged on a straight line and is electrically connected to the power supply terminals 111, 211, 311 by the conductor on the multilayer wiring portion 503, and the flat conductors 102, 103 are also arranged on the straight line and are mutually conductive. The plate conductor 104 is connected to power terminals 114, 214, and 314, which are arranged on a straight line and are electrically connected to each other, to the power terminals 112, 212, 312 and 113, 213 and 313, respectively.

As apparent from FIG. 2A, the filter capacitors 41 to 43 in the positive-side arm filter capacitor connection circuit 4, the filter capacitors 51 to 53 in the negative-side arm filter capacitor connection circuit 5, and the power supply for each phase terminal 111～114,211～214,311～314 the center point of the V-phase three-level converter circuit 2, i.e., around the intersection of the positive and negative arms midline CL _C and V-phase centerline CL _V, 180 ° They are arranged symmetrically so that they are in a rotated position (point symmetry).
Furthermore, each phase both for the power supply terminal 111～114,211～214,311～314, so as to be point symmetrical about the intersection of the center line of the phase positive and negative arms midline CL _C, for example U-phase for, the power supply terminal 111 and the power supply terminal 114 and 113 are arranged so as to be point symmetrical about the intersection of the U-phase centerline CL _U positive and negative arm intermediate line CL _C.

  Although not shown in FIG. 2 (b), the IGBT modules 11 to 14, 21 to 24, 31 to 34 and the diode modules 15, 16, 25, and 26 constituting the respective phase three-level conversion circuits 1 to 3. , 35, and 36 are also symmetrically arranged in the module mounting portion 504 so that each phase is rotated 180 degrees around the middle point between the positive arm and the negative arm. It is mounted at a position where wiring can be most rationally arranged.

The terminals of each module are gathered at a convex portion 503a that protrudes on the opposite side (flat conductors 101 to 104) from each module at the center of the laminated wiring portion 503. The conductors on the surface of the convex portion 503a include power terminals 111, 211, and 311 for each phase (only the reference numeral 311 is shown in FIG. 2B for convenience), 112, 113, 212, 213, 312 and 313 ( also denoted only code 313), 114, 214, 314 (also denoted only code 314) is disposed, the back surface of the positive and negative arms midline CL _C and phase centerline _{CL U,} CL V, the CL _W The AC output terminals 115, 215, and 315 of the respective phases are arranged at the intersections.
By arranging the AC output terminals 115, 215, and 315 at the above positions, the output current on the laminated wiring portion 503 can be leveled in a plane.

  In the present embodiment, on the surface side of the laminated wiring portion 503, an example is shown in which the flat conductors 101 to 104 and each power supply terminal P, N, C are connected by one power supply terminal for each phase. However, they may be connected by a plurality of power supply terminals. Similarly, each of the AC output terminals 115, 215, and 315 on the back side may be constituted by a plurality of output terminals.

Next, FIG. 3 shows the power supply terminals P, C, N of the multilayer wiring portion 503 in this embodiment and the AC output terminals U, V, W of each phase connected to the AC output terminals 115, 215, 315. The wiring state is shown.
As shown in FIG. 3, the rear surface of the laminated wiring portion 503, disposed respectively an AC output terminal 115,215,315 negative arm intermediate line CL _C and phase centerline _{CL U,} CL V, the intersection of the CL _W By extending the wide conductor 510 from the gap between the upper surfaces to the upper surface, the power terminals 111, 211, 311, 112, 113, 212, 213, 312, 313, 114, 214, 314 and the power terminals P, It can be distinguished from the wide conductor 511 connecting C and N.

  By arranging the terminals of each phase in this way, the wide line conductors 510 and 511 extending to the external line terminals of the power unit, that is, the power supply terminals P, C and N and the AC output terminals U, V and W, are overlapped. It is possible to reduce the wiring inductance of the power supply and the AC output, and to reduce inductive disturbance to nearby electronic circuits.

4A is a cross-sectional view taken along line YY of FIG. 2A, and FIG. 4B is a right side view of FIG. 4A. U, V, W-phase filter capacitors 41 to 41 for the positive side arm 43 shows the connection state of the positive side arm filter capacitor connecting flat plate conductors 101 and 102. A and B are bipolar terminals of the filter capacitors 41 to 43, one being a positive terminal and the other being a negative terminal.
Here, the flat conductors 101 and 102 shown in FIG. 4 are referred to as a first embodiment of the flat conductor.

If the connection structure of the filter capacitors 41 to 43 and the flat conductors 101 and 102 shown in FIG. 4 is rotated by 180 ° around the connection terminal 112, for example, the negative arm U, V, and W phase filter capacitors 51 to 53 This is substantially the same as the connection structure with the negative side arm filter capacitor connection flat conductors 104 and 103. In other words, the flat conductors 101, 104 and 102, 103 can have the same shape and structure.
This is the same in the second to fourth embodiments of the flat plate conductor described later.
Here, since the overlapping wiring structure by the flat plate conductor and the flow of the commutation current are exactly the same on the positive side and the negative side, the characteristics of the overlapping wiring by the flat plate conductors 101 and 102 for the positive side arm will be described below.

In FIG. 4, the terminals A of the filter capacitors 41 to 43 for each phase are connected to a positive power flat plate conductor 101, and the terminal B is connected to a neutral point power flat plate conductor 102. Further, by sandwiching a thin insulating plate 501 as much as possible between the flat conductors 101 and 102 to withstand the applied voltage between the two conductors, the inductance of the wiring reaching the filter capacitor is minimized.
Furthermore, holes 101a and 102a are provided in the flat conductors 101 and 102 for retaining a spatial distance so as to sufficiently withstand the withstand voltage between the terminal B and the flat conductor 101 and the withstand voltage between the terminal A and the flat conductor 102, respectively. Is provided.
The flat conductor 101 for positive power supply has power terminals 111, 211, 311 connected to the positive power supply terminal P of the laminated wiring portion 503, and the flat conductor 102 for neutral power supply has a laminated wiring portion 503. Power supply terminals 112, 212, and 312 connected to the neutral point power supply terminal C are provided, respectively.

  Next, FIG. 5 shows the path i of the commutation current in FIG. 12A as a current path on the flat conductors 101 and 102 by a single line. In FIG. 5, the thick line indicates the main current to the commutation phase filter capacitor, the thin line indicates the shunt current to the other phase filter capacitor, the solid line indicates the current on the front plate conductor 102, and the dotted line indicates the back plate conductor 101. Current.

As shown in FIG. 5, the solid line current and the dotted line current flow between the terminals A and B and the power supply terminals P and C by overlapping with each other on the flat conductors 101 and 102 due to electromagnetic action. Inductance between terminals is effectively reduced. The commutation current path iv in FIG. 12B can be described in the same manner.
As described above, since the negative arm is arranged and wired symmetrically with the positive arm, the commutation current paths ii and iii of the filter capacitor of the negative arm in FIGS. This can be explained in the same manner as the positive side arm.

In FIG. 5, the commutation current is shown as a single line for simplicity of explanation, but the current on the positive power supply flat conductor 101 indicated by the dotted line and the neutral point power supply flat conductor indicated by the solid line. The current on 102 is actually a width-like current determined by the geometrical relationship between the terminals A and B of the filter capacitors of each phase and the power supply terminals P and C, and the currents on both plate conductors 101 and 102 are opposite to each other. Flow in the direction. As the width current flows in this manner, the wiring inductance is further effectively reduced.
Also, in the second to fourth embodiments described below, the commutation current is indicated by a single line, but the actual current is a width-like current determined by the geometrical relationship between the capacitor terminal and the power supply terminal.

FIG. 6 shows a second embodiment of the flat conductor. In this embodiment, the flat conductors 101A and 102A are provided with cutouts Cut1 and Cut2, respectively, in order to reduce the shunt current to the other-phase filter capacitor indicated by the thin line in FIG. It is.
That is, in FIG. 6, by providing the notches Cut1 and Cut2 in the vicinity of each of the power supply terminals 111 to 312, the path of the shunt current at the lower part between the phases of the flat conductors 101A and 102A is cut off.

FIG. 7 shows a third embodiment of the flat conductor. In this embodiment, notch portions Cut1 and Cut2 are provided between the filter capacitors 41 to 43 of each phase, respectively, at the lower portion of the flat conductor 101B and at the upper portion of the flat conductor 102B.
Thus, by forming a gap between the phases of the flat conductors 101B and 102B by the cutouts Cut1 and Cut2, it is possible to suppress the shunt currents from flowing in pairs.

  The above explanation is for a case where one filter capacitor is formed for each arm. In this case, as shown in FIGS. 4 to 7, the power terminals 111 to 312 of the plate conductors 101 (101A and 101B) and 102 (102A and 102B) are connected in the arrangement direction of the bipolar terminals A and B of the capacitor. It is parallel to the surface of the laminated wiring portion 503 (convex portion 503a) in FIG. Thereby, the current paths on the flat conductors 101 (101A, 101B) and 102 (102A, 102B) are symmetrical and shortest.

  Next, FIG. 8 shows a fourth embodiment of the flat conductor, in which the filter capacitor is composed of a plurality (two in FIG. 8) of capacitor units for each arm. That is, the filter capacitors 41 to 43 are configured by capacitor units 411, 412, 421, 422, 431, and 432 that are connected in parallel to each other.

In this case, the filter capacitors 41 to 43 are arranged adjacent to each other, and the arrangement direction of the bipolar terminals A and B of the capacitor units 411, 412, 421, 422, 431, and 432 depends on the power supply of the plate conductors 101C and 102C. It is perpendicular | vertical with respect to the surface of the laminated wiring part 503 (convex part 503a) of FIG.2 (b) to which the terminals 111-212 are attached. Further, adjacent capacitor units are alternately arranged with terminals A and B, and all the terminals are aligned in two rows on a straight line and connected to the flat conductors 101C and 102C.
In FIG. 8, notches Cut1 and Cut2 for suppressing the shunt current are formed between the phases of the flat plate conductors 101C and 102C as in FIG.

FIG. 9 shows current paths on the flat conductors 101C and 102C for the respective phase currents in this embodiment.
Since the capacitor units 411, 412, 421, 422, 431, and 432 constituting the filter capacitors 41 to 43 are sequentially arranged so that the terminals A and B of different polarities are adjacent to each other, the current flowing through the upper terminals The current flowing through the lower terminal is in the opposite direction, and these currents flow in a pair to overlap, so that the inductance of the wiring is effectively reduced.

  In the above-described embodiment, the case where the present invention is applied to a three-phase three-level inverter has been described. However, in the case of a two-phase three-level converter, a wiring structure such as a filter capacitor, a flat conductor, and a laminated wiring section similar to the above- A connection structure can be applied. Further, when the switching elements and the coupling diodes constituting each arm are used by a plurality of parallel connections, the same wiring structure and connection structure can be applied.

It is a wiring diagram showing an embodiment of the present invention. It is a structure figure of the power unit in an embodiment. It is a figure which shows the wiring state of the power terminal and alternating current output terminal in embodiment. It is a figure which shows the connection state of the filter capacitor and flat plate conductor in 1st Example of a flat plate conductor. It is the figure which showed the electric current path | route on the flat conductor in FIG. It is a figure which shows the connection state of the filter capacitor and flat plate conductor in 2nd Example of a flat plate conductor. It is a figure which shows the connection state of the filter capacitor and flat plate conductor in 3rd Example of a flat plate conductor. It is a figure which shows the connection state of the filter capacitor and flat plate conductor in 4th Example of a flat plate conductor. It is the figure which showed the electric current path on the flat conductor in FIG. It is a main circuit block diagram of an AC train. It is a main circuit block diagram of a 3 level inverter. It is a figure which shows the commutation circuit of the U phase in FIG.

Explanation of symbols

1: U phase 3 level conversion circuit 2: V phase 3 level conversion circuit 3: W phase 3 level conversion circuit 4: Filter arm connection circuit for positive side arm 5: Filter capacitor connection circuit for negative side arm 11-14: U phase IGBT modules 21-24: V-phase IGBT modules 31-34: W-phase IGBT modules 15, 16: U-phase diode modules 25, 26: V-phase diode modules 35, 36: W-phase diode modules 41, 42, 43: positive side U, V, W phase filter capacitors for arms 51, 52, 53: U, V, W phase filter capacitors for negative side arms 101, 102, 101A, 102A, 101B, 102B, 101C, 102C: Filter capacitors for positive side arms Connecting plate conductors 101a, 102a: holes 103, 104: negative arm arm Filter capacitor connection flat conductor (101: positive power supply flat conductor, 104: negative supply flat conductor, 102, 103: neutral power flat conductor)
111 to 114: U phase filter capacitor DC power supply terminal 211 to 214: V phase filter capacitor DC power supply terminal 311 to 314: W phase filter capacitor DC power supply terminal 115: U phase output terminal 215: V phase output terminal 315: W phase output Terminals 411, 412, 421, 422, 431, 432: Capacitor units 501, 502: Insulating plate 503: Laminated wiring part 503 a: Convex part 504: Module mounting part 505: Cooling body heat receiving part 510, 511: Wide conductor P, C , N: Power supply terminals U, V, W: AC output terminals A, B: Terminals CL _C : Positive / negative arm intermediate line CL _U : U-phase center line CL _V : V-phase center line CL _W : W-phase center line Cut1, Cut2 : Notch

Claims (5)

A plurality of three-level conversion circuits, and a plurality of filter capacitors provided corresponding to these three-level conversion circuits,
A switching element and a coupling diode element constituting the three-level conversion circuit are mounted on a cooling body heat receiving part common to all phases, and the terminals of each element are connected by a laminated wiring part formed by sandwiching an insulating plate between conductors. And a three-level power conversion device in which the filter capacitor disposed in the vicinity of the multilayer wiring portion is connected to a DC terminal of the three-level conversion circuit.
The filter capacitors of each phase are arranged separately on the positive arm side and the negative arm side, and on each arm side, two flat conductors for connecting the terminals of the same polarity of each filter capacitor to the DC terminal, Lay out the insulating plates and arrange them,
The laminated wiring portion includes a convex portion that protrudes on the opposite side of each element between the positive side arm and the negative side arm, and each phase DC terminal of the three-level conversion circuit on the surface of the convex portion, An AC terminal is arranged on the back surface at a symmetrical position around a specific point on the intermediate line between the positive side arm and the negative side arm, and each phase DC terminal is connected to the corresponding flat plate conductor. A three-level power converter. The three-level power converter according to claim 1,
3. The three-level power converter according to claim 1 , wherein the flat arm and the insulating plate on the positive arm side and the negative arm side have the same shape and the same structure . In the three-level power converter according to claim 1 or 2,
3. A three-level power converter according to claim 1, wherein a cutout portion for reducing a shunt current flowing from a DC terminal of one phase to a terminal of a filter capacitor of another phase is provided in the flat conductor . In the 3 level power converter device given in any 1 paragraph of Claims 1-3 ,
3. A three-level power converter according to claim 1, wherein when one filter capacitor is formed for each arm, the arrangement direction of the bipolar terminals of each filter capacitor is parallel to the surface of the multilayer wiring portion . The three-level power converter according to any one of claims 1 to 3 ,
3-level power filter capacitor to be composed in each arm hit multiple pieces of capacitor unit, the arrangement direction of the extremes terminal of each capacitor unit, characterized in that the perpendicular to the surface of the laminated wiring portion Conversion device.

Images