JP3786320B2 - Inverter module for motor drive - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an inverter module for driving a motor in which a three-phase inverter circuit is mounted on a single substrate, and more particularly to an inverter module for driving a regenerative motor that performs motor operation and regenerative operation.
[0002]
[Prior art]
An inverter module for driving a motor can widely recover rotational energy of a load as electric power to a DC power source side by regenerative operation during braking, and is therefore widely used for motor drive control for driving a traveling motor of an electric vehicle.
Japanese Patent Laid-Open No. 4-152663 discloses an inverter module in which two arms out of six arms constituting a three-phase inverter circuit, that is, one phase is mounted.
[0003]
In this inverter module, each arm is composed of three switching semiconductor elements connected in parallel to each other and three refluxing semiconductor elements connected in reverse parallel to these switching semiconductor elements. The three switching semiconductor elements of the arm are disposed adjacent to each other on the substrate, and the three return semiconductor elements of each arm are also disposed adjacent to each other on the substrate.
[0004]
[Problems to be solved by the invention]
In the conventional inverter module described above, the three switching semiconductor elements are adjacent to each other and the three return semiconductor elements are adjacent to each other. In the case of output, the heat generated by the three adjacent switching semiconductor elements influences each other, increasing the temperature thereof, and the three return semiconductor elements as in the regenerative operation of the motor. When is operated, the heat generation of the three adjacent semiconductor devices for reflux affected each other, and their temperature increase increased.
[0005]
In addition, a conductor pattern is provided on the insulating substrate of the inverter module. However, the heat generated by the conductor pattern affects adjacent switching semiconductor elements and refluxing semiconductor elements. was there.
By increasing the size of the inverter module and increasing the element arrangement density and the conductor pattern, these problems of increasing the temperature of the element can be alleviated. However, increasing the size of the inverter module increases the cost and increases the installation space. I will invite you.
[0006]
The present invention has been made in view of the above-described problems, and an object thereof is to provide an inverter module capable of realizing a reduction in element temperature without increasing the physique.
[0007]
[Means for Solving the Problems]
On inverter module for driving a motor according to claim 1 is constituted by parallel-connected plurality of switching semiconductor element and each of the switching semiconductor element and the respective anti-parallel-connected plurality of free wheeling semiconductor element An inverter module for driving a motor having a phase inverter circuit in which an arm and a lower arm are connected in series , wherein the plurality of switching semiconductor elements and the plurality of refluxing semiconductor elements of the upper arm alternate in a predetermined direction on the substrate The plurality of switching semiconductor elements and the plurality of refluxing semiconductor elements of the lower arm are alternately arranged adjacent to each other in a predetermined direction on the substrate .
According to a preferred aspect of the inverter module for driving a motor according to the first aspect, a plurality of switching semiconductor elements and reflux semiconductor elements constituting each arm of the three-phase inverter circuit are disposed on the insulating substrate. In this configuration, in particular, the switching semiconductor elements and the reflux semiconductor elements are alternately arranged adjacent to each other in a predetermined direction.
[0008]
In this way, the switching semiconductor elements that are energized and heated at the same time or the semiconductor elements for reflux are not brought close to each other, so that the temperature rise of the semiconductor elements for switching can be reduced, and the temperature rise of the semiconductor elements for reflux can be reduced. Can be reduced. That is, the switching semiconductor element and the refluxing semiconductor element are hardly energized simultaneously even if they are in the same arm.
[0009]
Therefore, by arranging the switching semiconductor element and the refluxing semiconductor element next to each other, the switching semiconductor elements that operate at the same time are thermally affected by each other, and the temperature of the switching semiconductor elements increases. Similarly, the semiconductor devices for reflux that operate simultaneously do not affect each other thermally and their temperature does not rise, and the rise in device junction temperature can be suppressed, improving reliability, A great effect such as an increase in current can be achieved.
[0010]
In addition, as a pair of switching semiconductor elements arranged across the semiconductor elements for reflux, the same phase and the same side (same arm), the same phase on the opposite side, the different phase on the same side Or a different phase and a different side.
For example, in the case of the same phase and the opposite side, the AC output potential of the phase inverter circuit of this phase changes in the alternating current in the alternating current output. Although they are 180 degrees out of phase but operate synchronously, they can be regarded as operating simultaneously and generating heat simultaneously. Similarly, since switching semiconductor elements of different phases output a three-phase AC voltage, they are operated almost simultaneously although they are different in phase, and can be considered to generate heat simultaneously.
[0011]
When a three-phase inverter circuit is operated to output a three-phase AC voltage, a flyback current flows to the return semiconductor element due to the disconnection of the switching semiconductor element, and both the switching semiconductor element and the return semiconductor element generate heat.
However, a traveling motor such as an electric vehicle performs a regenerative (braking) operation. In this regenerative operation, the generated alternating current is rectified and output by a three-phase full-wave rectifier circuit composed of each refluxing semiconductor element. . Therefore, the amount of current flowing through the return semiconductor element during the regenerative operation is much larger than the flyback current when the switching semiconductor element is shut off, and the return semiconductor element is manufactured accordingly. That is, at the time of regeneration, the motor becomes a powerful three-phase AC generator, and a power generation current much larger than the flyback current when the switching semiconductor element is disconnected flows through each return semiconductor element as a three-phase full-wave rectifier.
[0012]
In other words, the semiconductor circuit for reflux mainly generates heat during regeneration, and the semiconductor element for switching mainly generates heat during power running. By arranging these elements alternately, it is possible to alleviate the concentration of heat generation and to suppress the temperature rise of the element. it can.
According to the configuration of the second aspect, in the inverter module according to the first aspect, the plurality of switching semiconductor elements and the plurality of refluxing semiconductor elements of the same phase, the same side, that is, the same arm are alternately arranged in a line. The A conductor pattern forming a low DC end or an AC output end of the phase inverter circuit is provided adjacent to one side of the element array.
[0013]
In this case, the upper main electrode of the switching semiconductor element and the reflux semiconductor element of the same arm can be connected to the conductor pattern by wire bonding at the shortest distance, and the wiring configuration is simplified. According to the configuration described above, in the inverter module according to claim 2, the conductor pattern forming the control input terminal for controlling the switching semiconductor element in the element row is extended adjacent to the other side of the element row. .
[0014]
In this way, the control electrode of the switching semiconductor element of the same arm can be connected to the conductor pattern by wire bonding at the shortest distance, and the wiring configuration is simplified .
[0016]
DETAILED DESCRIPTION OF THE INVENTION
For the power switching element, MOS, bipolar, SIT, IGBT or the like can be adopted.
The three-phase inverter circuit may have a fourth phase inverter circuit for controlling the neutral current of the star connection motor.
Example 1
A circuit of a three-phase AC motor control device for an electric vehicle using the three-phase inverter module of the present invention is shown in FIG.
[0017]
(overall structure)
1 is a three-phase inverter module, 2 is a battery, 4a and 4b are relays, 6 is a three-phase AC motor that is a running motor of an electric vehicle, 7 is a current sensor, 8 is an internal controller, and 9 is a switch Reference numeral 10 is an auxiliary battery, 11 is a vehicle electronic control circuit, 13 is a gate controller, 14 is a voltage abnormality detection protection circuit, 15 is a motor controller device, and 27 is a smoothing capacitor.
[0018]
The three-phase inverter module 1 is mounted on a single base and is composed of six arms 3a to 3f as is well known, and the upper arm 3a and the lower arm 3b are connected in series to each other in the U-phase. Phase inverter circuit, and upper arm 3c and lower arm 3d are connected in series to form a V-phase phase inverter circuit, and upper arm 3e and lower arm 3f are connected in series to each other. Thus, a W-phase inverter circuit is configured.
[0019]
The upper arm 3a includes an IGBT 31a that is a switching semiconductor element, and a diode 32a connected in reverse parallel thereto. The lower arm 3b includes an IGBT 31b which is a switching semiconductor element, and a diode 32b connected in reverse parallel thereto.
The upper arm 3c includes an IGBT 31c, which is a switching semiconductor element, and a diode 32c connected in reverse parallel thereto. The lower arm 3d includes an IGBT 31d which is a switching semiconductor element, and a diode 32d connected in reverse parallel thereto.
[0020]
The upper arm 3e is composed of an IGBT 31e which is a switching semiconductor element and a diode 32e connected in reverse parallel thereto. The lower arm 3f includes an IGBT 31f which is a switching semiconductor element, and a diode 32f connected in reverse parallel thereto.
The IGBTs 31a to 31f that are switching semiconductor elements are each formed by connecting three IGBT chips in parallel, and the diodes 32a to 32f that are refluxing semiconductor elements are each formed by connecting three diode chips in parallel.
[0021]
Reference numerals 35a, 35c and 35e denote high-level DC terminals of the three-phase inverter module 1, which are connected to the high-level terminals of the battery 2 through the buses 4a and 4b through the bus bars. Reference numerals 35b, 35d, and 35f denote low DC terminals of the three-phase inverter module 1, which are connected to the high terminals of the battery 2 through bus bars. Reference numerals 36 to 38 denote AC output terminals of the three-phase inverter module 1, which supply power to the three-phase AC motor 6 through a cable.
When the start switch 9 is turned on, the control circuit 8 is supplied with electric power from the auxiliary battery 10, and receives an accelerator command signal from the vehicle electronic control circuit 11 and a detection signal from the current sensor 7, The gate voltage of each IGBT 31a-31f of the module 1 is controlled. Here, the control circuit 8 uses the auxiliary battery 10 as a power source to apply and release the voltage to the gates of the IGBTs 31a to 31f, and the main voltage for monitoring the DC power supply voltage and protecting it in the event of an abnormality. An abnormality protection circuit 14 is incorporated.
[0022]
(basic action)
The basic operation of this apparatus will be briefly described below.
When the switch 10 is turned on by the vehicle electronic control circuit 11, the internal controller 8 is activated, and when the relays 4 a and 4 b are sequentially turned on, power is supplied to the three-phase inverter module 1. The internal controller 8 controls the gate voltages of the IGBTs 31a to 31f based on the current signals detected from the current sensor 7 and the signals from the three-phase inverter module 1 and the vehicle electronic control circuit 11, and outputs them to a predetermined value. The three-phase AC power is supplied to the three-phase AC motor 6 intermittently in order. The smoothing capacitor 27 suppresses voltage fluctuation of the DC voltage input to the three-phase inverter module 1.
[0023]
(Detailed structure of three-phase inverter module 1)
A schematic plan view of the three-phase inverter module 1 is shown in FIG. 2, and a cross-sectional view taken along line AA is shown in FIG.
There is provided a base 20 on a flat plate made of a composite material obtained by impregnating a ceramic material (for example, SiC) with aluminum and having excellent thermal conductivity and mechanical strength.
[0024]
On the upper surface of the base 20, the green substrate 21 to 21 such as a ceramic substrate made of AIN having a good thermal conductivity is formed by known soldering or aluminum brazing or fusion bonding with aluminum contained in the base 20. 23 is joined. As the base 20, for example, a metal made of Cu having excellent heat conduction can be used. In the case of metal, for example, Cu and Mo or an alloy of Cu and W is used in order to make the thermal expansion coefficient of the green substrate 21 to 23 mounted on the base 20 close to the thermal expansion coefficient of the base member 20. May be.
[0025]
Six conductor patterns (for example, Cu or Al) 24a, 24b, 24c, 24d, 24e, and 24f are joined to the upper surfaces of the insulating substrates 21 to 23 by brazing. The IGBTs and the diodes described above are joined to the upper surfaces of the conductor patterns 24a to 24f by soldering. On the insulating substrates 21 to 23, six conductor patterns 25a, 25b, 25c, 25d, 25e, and 25f are also joined.
[0026]
As described above, the IGBT 31a includes the IGBTs 31la, 312a, and 313a connected in parallel, and the diode 32a includes the diodes 321a, 322a, and 323a connected in parallel. Similarly, the IGBT 31b includes IGBTs 31lb, 312b, and 313b connected in parallel, and the diode 32b includes diodes 321b, 322b, and 323b connected in parallel. The IGBT 31c includes IGBTs 31lc, 312c, and 313c connected in parallel, and the diode 32c includes diodes 321c, 322c, and 323c connected in parallel. Similarly, the IGBT 31d includes IGBTs 31ld, 312d, and 313d connected in parallel, and the diode 32d includes diodes 321d, 322d, and 323d connected in parallel. Further, the IGBT 31e includes IGBTs 31le, 312e, and 313e connected in parallel, and the diode 32e includes diodes 321e, 322e, and 323e connected in parallel. Similarly, the IGBT 31f includes IGBTs 31lf, 312f, and 313f connected in parallel, and the diode 32f includes diodes 321f, 322f, and 323f connected in parallel.
[0027]
A resin insulating case 26 is bonded to the peripheral edge of the base 20, and high-level DC terminals 35a, 35c, 35e, low-level DC terminals 35b, 35d, 35f and an AC output are formed on the upper surface of the insulating case 26. Terminals 36 to 38 are fixed by insert molding. Although not shown, the positive and negative terminals of the smoothing capacitor 27 are fixed by a bus bar between the high-level DC terminals 35a, 35c, and 35e and the low-level DC terminals 35b, 35d, and 35f. A three-phase AC motor 6 is connected to 38.
[0028]
The IGBTs 311a, 312a, 313a and the diode chips 321a, 322a, 323a are alternately arranged in a row as shown in the figure. The above configuration is the same for the other five arms 3b to 3f, but the description thereof is omitted.
Higher DC terminals 35a, 35c, and 35e connected to the positive electrode of the DC power source are individually connected to the conductor patterns 24a, 24c, and 24e. The conductor patterns 24a, 24c, and 24e are connected to the IGBT chip and the diode chips 311a, 312a, and 313a, respectively. Main electrodes on the upper surfaces of 321a, 322a, 323a, 311c, 312c, 313c, 321c, 322c, 323c, 311e, 312e, 313e, 321e, 322e, and 323e are connected by a bonding wire.
[0029]
The lower DC terminals 35b, 35d, and 35f connected to the negative electrode of the DC power source are individually connected to the conductor patterns 25b, 25d, and 25f. The conductor patterns 25b, 25d, and 25f are the IGBT chip and the diode chips 311b, 312b, 313b, and 321b. 322b, 323b, 311d, 312d, 313d, 321d, 322d, 323d, 311f, 312f, 313f, 321f, 322f, and 323f are connected by bonding wires to the main electrodes.
[0030]
The AC output terminals 36 to 38 are connected to the conductor patterns 24b, 24d, and 24f by bonding wires. The AC output terminals 36 to 38 are IGBT chips and diode chips 311a, 312a, 313a, 321a, 322a, 323a, 311c, 312c, 313c, 321c, 322c, 323c, 311e, 312e, 313e, 321e, 322e, The conductor patterns 25a, 25c, and 25e, which are conductively connected to the H.323e by the bonding wire, are connected by the bonding wire.
[0031]
The IGBT chips 311a to 313a, 311b to 313b, 311c to 313c, 311d to 313d, 311e to 313e, 311f to 313f, and conductor portions 39a, 39b, 39c, 39d, 39e, and 39f insert-molded in the insulating case 26 are They are connected by bonding wires 40a, 40b, 40c, 40d, 40e, and 40f, and the conductor portions 39a to 39f are soldered to the control circuit 8 disposed immediately above.
[0032]
(Operation of three-phase inverter module 1)
Hereinafter, the operation of the three-phase inverter module 1 will be described.
During the power running operation of the three-phase AC motor 6, the energization currents of the IGBTs 31a to 31f are much larger than those of the diodes 32a to 32f, and the heat generation of the IGBTs 31a to 31f becomes dominant. That is, the diodes 32a to 32f operate as known circulating diodes required for driving an inductive load, so that the average current and the heat generation of the diodes 32a to 32f are larger than those of the IGBTs 31a to 31f. It is extremely small. On the other hand, during the regenerative operation, the conduction relationship between the IGBTs 31a to 31f and the diodes 32a to 32f is reversed, the diodes 32a to 32f are predominantly energized to generate heat, and the losses of the IGBTs 31a to 31f are the diodes 32a to 32f. This is much smaller than the loss of 32f. In the case of an electric vehicle, the power running state corresponds to normal running, and the regenerative state corresponds to a braked state. That is, both of them do not generate the maximum loss at the same time.
[0033]
Hereinafter, the upper arm of the U phase will be described, but the operation is the same for the other arms. Since the loss or heat generated in the IGBT chips 311a, 312a, 313a is cooled by the base 20, heat is transferred while spreading at an angle of about 45 degrees from the IGBT chips 311a, 312a, 313a toward the base 20. To do. Therefore, the heat flows between the IGBT chips during the power running operation and between the diode chips during the regenerative operation do not overlap, the device junction temperature can be kept low, the current flowing through each chip is not limited to a low level, and And chip reliability can be improved.
[0034]
Other features of this embodiment will be described below with reference to the lower arm of the W phase.
The emitters (main electrodes on the upper surface side of the chip) of the three IGBT chips 311f, 312f, and 313f connected in parallel are connected to the conductor pattern 25f by bonding wires, and the conductor pattern 25f is connected to the low-order DC terminal via the bonding wires. 35f is connected. The current flowing through the conductor pattern 25f increases as it goes from the IGBT chip 313f to 311f. Therefore, the current density can be made uniform in a small space by gradually increasing the width of the conductor pattern 25f in the above direction.
[0035]
Next, since the second arm from the left is on the high side, the direction of current flow is opposite to that on the low side. The width of the conductor pattern 25e connected by wire bonding from the emitters of the IGBT chips 311e, 312e, and 313e is gradually increased toward the AC output terminal.
Eventually, the width of the conductor pattern for the AC output terminals adjacent to each other and the width of the conductor pattern for the low-order DC terminals spread in opposite directions, so that the resistance at the portion where the current increases decreases, and the wiring loss and heat generation as a whole. Further, the space for arranging the conductor pattern can be saved. Furthermore, since the conductor patterns for the AC output terminal and the low-order DC terminal are close to the IGBT chip or the diode chip, the element temperature can be reduced by reducing the heat generation of these conductor patterns.
[0036]
Still other features of this embodiment will be described below with reference to the lower arm of the W phase.
In this embodiment, the conductor pattern 24e has a potential on the positive electrode side of the DC power source 2. Therefore, the conductor pattern 24e is connected to the conductor in the conductor portion 39e conducted to the control circuit 8 by the bonding wire 60.
[0037]
With the above configuration, the positive potential of the DC power supply 2 can be easily detected by the control circuit 8 overlying it simply by adding bonding wires one by one without the need for a cable. The conductor portions 39a to 39f are generic names including a plurality of electrically independent conductors equal to or more than the number of bonding wires to be connected. Similarly, the negative potential can be introduced from the conductor 25f to the control circuit 8 in the same manner without using a cable. The direct current positive potential detected by the control circuit 8 in this way is different from the negative potential and can be used in the main voltage abnormality protection circuit 14. The bonding wire 60 may be provided on the conductor pattern 24a or 24c, which has the same potential as the potential on the positive electrode side of the DC power supply 2.
[Brief description of the drawings]
FIG. 1 is a circuit diagram showing an embodiment of a motor control device employing a three-phase inverter module of the present invention.
FIG. 2 is a plan view of the three-phase inverter module 1 shown in FIG.
3 is a longitudinal sectional view taken along line AA of the three-phase inverter module 1 shown in FIG.
[Explanation of symbols]
1 is a three-phase inverter circuit,
2 is a battery,
31a to 31f are IGBTs (switching semiconductor elements),
32a to 32f are diodes,
6 is a three-phase AC motor,
20 is the base,
21 to 23 are insulating substrates,
24a to 24f and 25a to 25f are conductor patterns,
26 is the case,
35a, 35c, 35e are high-level DC terminals of the three-phase inverter module 1,
35b, 35d, and 35f are low DC terminals of the three-phase inverter module 1,
36 to 38 are AC output terminals,
311a, 312a, and 313a are U-phase high-side IGBTs,
311b, 312b, and 313b are U-phase low-side IGBTs,
Reference numerals 311c, 312c, and 313c denote V-phase high-side IGBTs,
311d, 312d, and 313d are V-phase low-side IGBTs,
311e, 312e, 313e are W-phase high side IGBTs,
311f, 312f, 313f are W-phase low-side IGBTs,
321a, 322a, 323a are U-phase high-side diodes,
321b, 322b, 323b are U-phase low side diodes,
321c, 322c, and 323c are high-side diodes for the V phase,
321d, 322d, and 323d are V-phase low-side diodes,
321e, 322e, and 323e are high-side diodes of the W phase,
Reference numerals 321f, 322f, and 323f are low-side diodes of the W phase.

Claims (3)

Phase inverter circuit parallel-connected plurality of switching semiconductor elements and said upper and lower arms constructed in accordance with the switching semiconductor element and the respective anti-parallel-connected plurality of free wheeling semiconductor elements which are connected in series An inverter module for driving a motor having
The plurality of switching semiconductor elements and the plurality of refluxing semiconductor elements of the upper arm are alternately arranged adjacent to each other in a predetermined direction on the substrate, and the plurality of switching semiconductor elements and the plurality of the refluxing semiconductor elements of the lower arm are disposed on the substrate. An inverter module for driving a motor, wherein the inverter modules are alternately arranged adjacent to each other in a predetermined direction . In the inverter module for driving a motor according to claim 1,
Same phase, has an element row formed by alternately arranged in a row a plurality of said switching semiconductor element and a plurality of said free wheeling semiconductor elements of the same side, adjacent to one side of the element rows, parallel to the element array to the phase inverter - inverter module for driving a motor, characterized in that to guide material pattern such a low DC terminal or alternating current output terminal of the capacitor circuit is extended before Kimoto board. The inverter module for driving a motor according to claim 2,
Adjacent the other side of the element row, parallel to the element array, that the previous SL same phase, a plurality of to conductors pattern the control input for controlling the semiconductor element for switching the same side are extended An inverter module for motor drive.

Images