JP5950800B2 - Power converter - Google Patents

Description

  The present invention relates to a power conversion apparatus using a module in which semiconductor switching elements are connected in series, and more particularly to a structure for mounting a power conversion apparatus configured by connecting a plurality of modules in parallel.

  Power conversion devices using high-speed semiconductor switching elements such as insulated gate bipolar transistors (IGBTs) are used in various fields. Particularly in recent years, large-capacity semiconductor modules have been realized by the advancement of semiconductor technology. As for modularization, not only the individual semiconductor switches are modularized, but also a large number of semiconductor modules in the arm portion in which the upper and lower semiconductor switches constituting the arm of the inverter are formed as one module. In order to increase the capacity, a plurality of arm module semiconductor modules may be connected in parallel.

  Thus, in order to increase the capacity, parallel connection of the semiconductor modules in the arm part is unavoidable. However, in the case of parallel connection, if the current sharing of each semiconductor element module is not equalized, the semiconductor element module on the heavy duty side must be used. Since usage conditions or lifespans are determined, it is necessary to balance them.

  The main factors that contribute to current equalization in the case of parallel connection of the semiconductor modules in the arm portion include differences in semiconductor element characteristics, differences in gate drive circuits, differences in main circuit wiring inductance, and the like. Therefore, if measures are taken for each of these factors, current equalization can be realized.

  As a specific approach for this purpose, for example, a measure such as selecting a characteristic difference between parallel elements is often taken for differences in element characteristics. For the gate drive circuit, countermeasures such as a common drive power supply circuit for the parallel elements and the same gate wiring length are taken.

  For equalizing the main circuit wiring inductance, there are methods as shown in Patent Document 1 and Patent Document 2. Patent Document 1 has a structure that reduces and equalizes the inductance of a smoothing capacitor serving as a DC power source and upper and lower IGBT circuit circuits. As shown in FIG. 23 of Patent Document 1, a positive electrode and a negative electrode conductor are laminated conductors. It is said.

  Moreover, in patent document 2, in order to suppress the inductance nonuniformity to the load from the alternating current terminal of the IGBT module connected in parallel, the device, such as providing a notch, is devised.

JP 2007-151286 A JP 2012-95472 A

  The countermeasures in each of the above viewpoints have been implemented respectively. Of these, the difference in semiconductor element characteristics will be described in detail. Regarding the characteristic selection of the semiconductor switch IGBT, the saturation voltage Vce (sat) governing the conduction loss is described. Easy to sort, such as being ranked. However, the gate threshold voltage Vge (th) and the input capacitance Cies are not normally selected. In such a case, current unevenness occurs if the semiconductor element characteristics are extremely different.

  Thus, in the power conversion device in the state where the semiconductor modules in the arm portion are connected in parallel and finally mounted in the housing (or storage panel), the wiring conductors around the IGBT module are mounted with high density. Therefore, it is difficult to actually measure current sharing between the semiconductor modules of the plurality of arm portions in a state where the power conversion device is assembled.

  From the above, the problem to be solved by the present invention is to provide a configuration that makes it easy to actually measure current sharing in a state where the power converter is assembled.

  In order to solve the above problems, the present invention provides a power conversion device for performing power conversion between alternating current and direct current, wherein the first positive electrode side switching element and the first negative electrode side switching element are in series. By connecting the connected first semiconductor circuit and the second semiconductor circuit in which the second positive electrode side switching element and the second negative electrode side switching element are connected in series, the power for one phase of alternating current is obtained. In charge of conversion, the first and second semiconductor circuits are each modularized, and the modularized first semiconductor circuit includes a first positive-side switching element and a first negative-side switching element. A second semiconductor circuit that is modularized and includes a first AC terminal that is a connection point is a second connection point that is a connection point between the second positive-side switching element and the second negative-side switching element. A first AC conductor that includes a current terminal and connects a load to the first AC terminal and a second AC conductor that connects the load to the second AC terminal are the first and second AC terminals. It is connected by another third terminal.

  By setting it as the above structures, it becomes possible to observe a current non-uniformity in the state which assembled the power converter device.

The figure which shows the structure which connected multiple semiconductor modules in parallel. The figure which shows the example of the power converter device comprised by two sets of AC / DC converter circuits. The figure showing the front surface of the structure which connected the semiconductor module in parallel. The figure which shows the side view when double-sided mounting is carried out. The figure which shows the example which accommodated the power converter device comprised by two sets of AC / DC converter circuits in the housing | casing. The figure which shows the structure of U-phase common connection terminal TBU3 as common connection terminal TB. The figure which shows the example of the measured electric current.

  Embodiments of the present invention will be described below with reference to the drawings.

  In the following embodiments, the switching module will be described in the case where the semiconductor switching element IGBT and two free-wheeling diodes connected in reverse parallel to the IGBT are described. However, switching other than the IGBT is described. An element may be used.

  FIG. 2 shows an example of a power converter configured by two sets of AC / DC converter circuits. In this figure, two sets of AC / DC conversion circuits 1A and 1B are three-phase conversion circuits using a semiconductor switching element S (for example, IGBT), and one of the AC / DC conversion circuits 1A and 1B (for example, 1A) converts AC to DC. Then, the AC / DC conversion circuits 1A and 1B are converted to AC by the other (for example, 1B) through the DC circuit.

  Specifically, in the AC / DC converter circuit 1B that performs inverter operation, the smoothing capacitor C is used as a DC power source, and the switching elements SBU, SBV, and SBW are turned off / on in accordance with an ignition signal from a control device (not shown). Thus, desired power is supplied to the load side (U, V, W phase side). In the AC / DC conversion circuit 1A that performs the converter operation, the AC power supply (R, S, T phase side) is turned off / on in response to the ignition signal from the control device (not shown). To convert to direct current and charge the smoothing capacitor C.

  A control device (not shown) controls the power conversion device by detecting the current flowing into and out of the power conversion device, the voltage of the DC circuit portion, the speed of the motor, and the like. In the figure, the description of the gate circuit that drives the switching element is omitted, and the description of the snubber circuit that is connected as necessary for the purpose of withstand voltage protection is also omitted.

  In addition, this invention is not necessarily applicable only to the power converter device 1 provided with 2 sets of AC / DC conversion circuits 1A and 1B, but 1 set of AC / DC conversion circuits (1A or 1B) which convert between alternating current and direct current | flow. It is applicable also to the power converter device comprised by these.

  In FIG. 2, the AC / DC converter circuit 1A is connected to an AC circuit indicated by R, S, and T phases, and the AC / DC converter circuit 1B is connected to an AC circuit indicated by U, V, and W phases. Further, the AC / DC conversion circuits 1A and 1B are obtained by connecting the semiconductor switching elements S to a three-phase Gratz connection, and the symbols A and B attached to the semiconductor switching elements S are elements on the AC / DC conversion circuits 1A and 1B side. Represent. Symbols R, S, T and U, V, W mean three-phase alternating current phases. Further, the positive side element (1) and the negative side element (2) in the arm configuration are distinguished by symbols 1 and 2 attached to the semiconductor switching element S.

  Symbol M represents a semiconductor element module in the arm portion. Symbols A and B and symbols R, S, T, U, V, and W attached thereto are distinguished from the AC / DC converter circuits 1A and 1B as described above. , Represents each phase of three-phase alternating current.

  As is clear from the above notation convention, for example, MAR is a semiconductor element module of the arm portion connected to the R phase of the AC / DC conversion circuit 1A, and MBU is a semiconductor of the arm portion connected to the U phase of the AC / DC conversion circuit 1B. It means an element module. Since the semiconductor element modules of the other arm portions can be understood in the same manner, description of the semiconductor element modules of the individual arm portions will be omitted.

  As the semiconductor element module of the arm portion, for example, the MAR has two semiconductor switching elements SAR1 and SAR2 connected in series, and the AC terminal that is the negative side terminal of the positive side switching element SAR1 and the positive side terminal of the negative side switching element SAR2 is Connected by conductor inside the module. Further, both ends of the two semiconductor switching elements SAR1 and SAR2 connected in series are connected to the positive side DC + and the negative side DC− of the DC circuit DC. Further, a smoothing capacitor C is installed between the positive and negative electrodes in the DC circuit DC.

  FIG. 1 shows a configuration in which a plurality of semiconductor modules of one arm portion in FIG. 2 are connected in parallel. Here, an example of the MBU is shown as the semiconductor module of the arm portion. MBUa and MBUb are connected in parallel in the semiconductor element module MBU of the arm portion connected to the U phase of the AC / DC converter circuit 1B.

  As shown in FIG. 1, the positive electrode side switching element SBU11 and the negative electrode side switching element SBU21 are configured by one module MBUa. Similarly, the positive side switching element SBU12 and the negative side switching element SBU22 are configured by one module MBUb. Further, the positive side switching elements SBU11 and SBU12 are connected in parallel, and the negative side switching elements SBU21 and SBU22 are connected in parallel. The positive-side conductor and the negative-side conductor are mounted so that the inductances of the switching modules connected in parallel are equal.

  The AC terminal TBUa3, which is a connection point between the positive electrode side switching element SBU11 and the negative electrode side switching element SBU21, and the AC terminal TBUb3, which is a connection point between the positive electrode side switching element SBU12 and the negative electrode side switching element SBU22, are connected at a terminal TBU3. It has a structure that couples two parallel inputs and outputs.

  In addition, the current detector 11 used for control of the power converter 1 is provided in the latter stage after the coupling. Although not shown in detail, the other two phases have the same structure.

  The external connection relationship between the two modules will be described in more detail. The semiconductor element modules MBUa and MBUb of the arm part are respectively connected to DC terminals (TBUa1, TBUa2, TBUb1, TBUb2) for connection to the DC circuit side and AC terminals (TBUa3) for connection to the AC circuit side (U phase). TBUb3). The DC terminals (TBUa1 and TBUb1) are connected to the positive DC + of the DC circuit, and the DC terminals (TBUa2 and TBUb2) are connected to the negative DC− of the DC circuit.

  In the present invention, the AC terminals (TBUa3 and TBUb3) for connecting to the AC circuit side (U phase) are commonly connected. The common connection terminal TBU3 is connected to the AC terminals (TBUa3 and TBUb3) via the wirings LBUa and LBUb. Are located at remote locations. Further, as will be apparent from the following drawings, the U-phase common connection terminal TBU3 is arranged together with the other-phase common connection terminals at the same location.

  FIG. 3A shows a plan view of a configuration in which the semiconductor modules of the arm portion are connected in parallel. The U-phase device arrangement is shown in the plan view. In this figure, reference numeral 13 denotes a cooling block for mounting the semiconductor modules MBUa and MBUb of the arm portion and for removing the heat generated here. The heat generated in the semiconductor module is transmitted from the cooling block 13 to the cooler 12 and radiated to the outside.

  3A, the four switching elements SBU11, SBU12, SBU21, and SBU22 in FIG. 1, and thus two modules MBUa and MBUb are attached to the cooling block 13 of the cooler 12. In FIG. Although a heat pipe type cooler is shown here, a heat sink may be used.

  The following points should be taken into consideration for this implementation. First, in order to suppress the jumping voltage during the operation of the switching module, it is necessary to reduce the inductance of the circuit that is composed of the module and the smoothing capacitor C. For this reason, when mounting the components of the two modules MBUa and MBUb, the DC terminals of the two modules are arranged on the center side, and the AC terminals TBUa3 and TBUb3 are mounted facing outward. In particular, the DC terminals of the two modules are mounted so that the positive terminal and the negative terminal face each other. In the example of FIG. 3A, the positive terminal TBUa1 and the negative terminal TBUb2 face each other, and the positive terminal TBUb1 and the negative terminal TBUa2 face each other.

  Although the mounting position of the smoothing capacitor C is not shown, it is mounted so that the inductances between the switching modules are equal. In the figure, the conductor wiring is not shown.

  Each of the semiconductor modules MBUa and MBUb of the arm part has a DC terminal (TBUa1, TBUa2, TBUb1, TBUb2) and an AC terminal (TBUa3 and TBUb3). The AC terminal TBUa3 and the common connection terminal TBU3 are connected by a wiring LBUa, and the AC terminal TBUb3 and the common connection terminal TBU3 are connected by a wiring LBUb. In this way, the two wirings LBUa and LBUb are introduced and connected to the U-phase common connection terminal TBU3 and led to the outside as the U-phase terminal. Although not shown, DC terminals TBUa1 and TBUb1 are commonly connected to the positive electrode of DC circuit DC, and DC terminals TBUa2 and TBUb2 are commonly connected to the negative electrode of DC circuit DC.

  FIG. 3A shows the front surface of the configuration in which the semiconductor modules of the arm portions are connected in parallel. However, the mounting density can be increased by arranging the back surface in the same way. FIG. 3B shows a side view when both sides are mounted. The phase of the back surface when mounting on both sides may be a different phase within the same AC / DC converter circuit, but if the power converter is configured with two AC / DC converter circuits as shown in FIG. It is preferable to use a phase in another AC / DC conversion circuit.

  FIG. 3B shows an example in which the semiconductor module MAR of the arm portion which is the R phase in the other AC / DC conversion circuit 1A is configured on the back surface. As shown in FIG. 2, in the power conversion device 1 composed of two sets of AC / DC converter circuits 1A and 1B, one AC / DC converter circuit functions as a converter and the other AC / DC converter circuit functions as an inverter. Is to be called a converter / inverter one-phase unit. On the back side, the semiconductor module MAR of the arm part is composed of MARa and MARb, and the two wirings LAR1 and LARb from here are introduced and connected to the R-phase common connection terminal TBR3 as the R-phase terminal. Guided outside. The U-phase common connection terminal TBU3 and the R-phase common connection terminal TBR3 are arranged together on the common terminal block TUR3.

  FIG. 4 shows a diagram in which the power conversion device configured by the two sets of AC / DC conversion circuits of FIG. Showing the relationship. Three sets of converter / inverter 1-phase unit Y (YUR, YVS, YWT) are arranged in the horizontal direction, with the cooler 12 on the upper side and the cooling block 13 on the lower side. Yes. A terminal block T is disposed on the front face of the housing 10. The terminal block T is composed of three terminal blocks TUR, TVS, and TWT arranged in series.

  Among them, the terminal block TUR is provided with a U-phase common connection terminal TBU3 and an R-phase common connection terminal TBR3. Similarly, the terminal block TVS has a V-phase common connection terminal TBV3 and an S-phase. Common connection terminal TBS3, and a W-phase common connection terminal TBW3 and a T-phase common connection terminal TBT3 are provided on the terminal block TWT. Wiring from the semiconductor modules of the arm portions connected in parallel is introduced and connected to each common connection terminal.

  FIG. 5 shows a configuration of a U-phase common connection terminal TBU3 as the common connection terminal TB. The wirings LBUa and LBUb from the semiconductor modules MBUa and MBUb of the plurality of arms in the same phase are connected by the common connection terminal TBU3 to be the U phase.

  In addition to the circuit components described above, the casing 10 also contains a DC circuit smoothing capacitor C or wiring for various connections. For this reason, the inside of a housing | casing is narrow, and generally it is difficult to actually measure the electric current sharing between the semiconductor modules of a several arm part in the state which assembled the power converter device.

  On the other hand, in the case of the present invention, the currents of the semiconductor modules of the plurality of arm portions can be actually measured at the common connection terminal portion of the terminal block T provided on the front surface of the housing 10. For example, since the U-phase common connection terminal TBU3 shown in FIG. 5 has terminals connected to two sets of semiconductor modules, each current can be measured at this portion.

  3 and FIG. 4, when the components are arranged, the switching terminals MAR, MAS, MAT, MBU, MBV, MBW of each phase in FIG. As shown in FIG. 1, a current detector that is versatile in the previous stage of the coupling terminal TBU3, the current flowing through the AC terminal TBUa3 of the first semiconductor module and the current flowing through the AC terminal TBUb3 of the second semiconductor module. It is possible to observe current non-uniformity in the mounted state.

  An example of waveforms measured by the present invention is shown in FIG. FIG. 6 shows U-phase part currents corresponding to FIG. 1, where iu is the U-phase current detected by the current detector 11, and iua is the module MBUa-side current of the U-phase current detected by the current detector 11a. , Iub represents the module MBUb side current of the U-phase current detected by the current detector 11b.

When the power converter of the present invention described in detail above is shown in the configuration of the U phase in FIG.
A first semiconductor circuit MBUa in which a first positive electrode side switching element SBU11 and a first negative electrode side switching element SBU21 are connected in series;
A second semiconductor circuit MBUb in which a second positive electrode side switching element SBU12 and a second negative electrode side switching element SBU22 are connected in series;
A first AC terminal TBUa3 that is a connection point between the first positive electrode side switching element SBU11 and the first negative electrode side switching element SBU21;
A second AC terminal TBUb3 which is a connection point between the second positive electrode side switching element SBU12 and the second negative electrode side switching element SBU22;
The first AC conductor LBUa that connects the first AC terminal TBUa3 and the load, the second AC terminal TBUb3, and the second AC conductor LBUb that connects the load are different from the first and second AC terminals. It can be said that they are connected by the three terminals TBU3.

1A, 1B: AC / DC converter circuits S, SBU, SBV, SBW, SBR, SBS, SBT: Semiconductor switching element C: Smoothing capacitor R, S, T: Three-phase AC phase U, V, W: Three-phase AC phase M, MBU, MBV, MBW, MAR, MAS, MAT: Arm element semiconductor element module DC: DC circuit DC +: Positive electrode side DC-: Negative electrode side MBUa, MBUb: Arm element semiconductor elements modules TBUa1, TBUa2 connected in parallel , TBUb1, TBUb2: DC terminal TBUa3, TBUb3: AC terminal 13: Cooling block 12: Cooler TBU3: Common connection terminals LBUa, LBUb: Wiring

Claims (6)

A power conversion device for performing power conversion between alternating current and direct current,
A first semiconductor circuit in which a first positive electrode side switching element and a first negative electrode side switching element are connected in series, and a second semiconductor circuit in which a second positive electrode side switching element and a second negative electrode side switching element are connected in series. As the semiconductor circuits are connected in parallel, they are in charge of power conversion for one phase of the alternating current, and the first and second semiconductor circuits are each modularized,
The modularized first semiconductor circuit includes a first AC terminal that is a connection point between the first positive electrode side switching element and the first negative electrode side switching element,
The modularized second semiconductor circuit includes a second AC terminal that is a connection point between the second positive electrode side switching element and the second negative electrode side switching element,
The first AC conductor connecting the first AC terminal and the load and the second AC conductor connecting the second AC terminal and the load are different from the first and second AC terminals. Connected with the third terminal ,
A power conversion device , wherein a current flowing through the first AC conductor, a current flowing through the second AC conductor, and a combined current flowing through a third terminal are observed in the third terminal portion . The power conversion device according to claim 1,
The modularized first and second semiconductor circuits are arranged on the front surface of a cooling block, and constitute the other phases of the alternating current. The modularized first and second semiconductor circuits The power converter is characterized in that the circuit is arranged on the back surface of the cooling block. The power conversion device according to claim 2, comprising a first AC / DC conversion circuit that converts first AC to DC and a second AC / DC conversion circuit that converts the DC to second AC,
The modularized first and second semiconductor circuits of the first AC / DC converter circuit are disposed on the front surface of the cooling block, and the second AC / DC converter is disposed on the back surface of the cooling block. A converter / inverter one-phase unit is formed by arranging the modularized first and second semiconductor circuits of a circuit. It is a power converter device of any one of Claims 1-3, Comprising:
Each component which comprises a power converter device is accommodated in the housing | casing, The said 3rd terminal is arrange | positioned in the position which opened the door of the housing | casing, The power converter device characterized by the above-mentioned. The power conversion device according to claim 3,
At least one of the first alternating current and the second alternating current is a three-phase alternating current;
Each component which comprises a power converter device is accommodated in the housing | casing, The converter / inverter 1 phase part unit of 3 sets is arrange | positioned and accommodated in parallel, The power converter device characterized by the above-mentioned. The power conversion device according to claim 5,
Each component constituting the power converter is housed in a housing, and a plurality of the third terminals corresponding to the three sets of converter / inverter one-phase units are arranged at a position where the door of the housing is opened. The power converter characterized by being made.

Images