JP2013115870A - Power conversion device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power conversion device that supports high frequency drive by stabilizing supply voltages.SOLUTION: A plurality of high side transistor units mh are provided for each phase, and are disposed between an output terminal OUT of the corresponding phase and a higher power line LP electrically in parallel and with independent control terminals. A plurality of high side gate drive circuits 10H_U1-U3 output gate drive signals to a plurality of corresponding high side transistor units mhu1-3. A plurality of high side power circuits 14H_U1-U3 feed supply voltages VDDH_U1-U3 to the corresponding high side gate drive circuits 10H_U1-U3. A lower arm is similarly divided into a plurality of low side transistor units.

Description

  The present invention relates to a power conversion device.

  FIG. 1 is a circuit diagram of a general power converter (inverter) 2r. The power converter 2r is used for driving a load 4 including a motor. The power conversion device 2 includes a high side transistor MH (U to W) and a low side transistor ML (U to W) provided for each phase (U to W), and a high side transistor MH (U to W) of each phase. A gate drive circuit 10H for driving the low-side transistor ML (U to W), a power supply circuit 14 for supplying power supply voltages VDDH and VDDL to the gate drive circuits 10H and 10L, and a gate drive circuit 10H And a controller 12 that generates a control command S1 for 10L.

  FIG. 2 is a cross-sectional view of the layout of the power conversion device 2r examined by the present inventors. The power conversion device 2r is divided into three cards. The controller card 30 mainly includes the controller 12 and the power supply circuit 14. Gate drive circuits 10H and 10L are mounted on the gate drive card 32. The output stage card 34 is equipped with U-, V-, and W-phase high-side transistors MH and low-side transistors ML.

  Connectors CN1 and CN2 are provided on the controller card 30 and the gate drive card 32, respectively, and the controller card 30 and the gate drive card 32 are electrically connected via the wiring WR1. Control command S1 and power supply voltages VDDH and VDDL are transmitted through this wiring WR1.

  The gate drive circuit 10H and the high side transistors MHU to MHW and the gate drive circuit 10L and the low side transistors MLU to MLW are connected via a control signal pin 36. The gate drive signal S2 output from the gate drive circuit 10 is input to the gates of the high side transistor MH and the low side transistor ML via the control signal pin 36.

JP 2003-125588 A

  In the layout of FIG. 2, since the electrical distance between the controller 12 and the high-side transistor MH and the low-side transistor ML is large, supply paths of the power supply voltages VDDH and VDDL between the controller 12 and the gate drive circuits 10H and 10L. (Also referred to as a power supply line) has a parasitic impedance component that cannot be ignored, that is, an inductance component and a resistance component. The power supply voltages VDDH and VDDL become unstable as the parasitic impedance component increases.

  In recent years, industrial vehicles such as forklifts have been trending toward higher frequency (higher speed) of inverters. For this purpose, power supply voltages VDDH and VDDL for the gate drive circuit 10 need to be stabilized. When the layout of FIG. 2 is adopted, in order to stabilize the power supply voltages VDDH and VDDL, it is necessary to connect a large-capacity smoothing capacitor in the immediate vicinity of the power supply terminals of the gate drive circuits 10H and 10L. A large-capacity smoothing capacitor is not desirable from the viewpoint of cost, area, heat generation, and the like.

  Patent Document 1 discloses a gate drive circuit such as an inverter. In the technique of Patent Document 1, a switching element (high-side transistor, low-side transistor), a gate drive circuit, a protection circuit, and a power supply circuit that supplies a power supply voltage to them are formed into a single module. According to this configuration, since the electrical distance between the power supply circuit and the gate drive circuit is reduced, the parasitic impedance can be reduced. However, since it is necessary to generate the power supply voltage for all the blocks such as the gate drive circuit and the protection circuit by a single power supply circuit, a large-capacity smoothing capacitor is still necessary. In addition, in an inverter that uses an industrial vehicle, a large capacity (high output) is required. However, it is difficult to make all units into a single module from the viewpoint of thermal design. Further, when a single module is used, the switching noise of the transistor increases, and malfunctions become a problem.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and one of exemplary purposes of an aspect thereof is power conversion that can stabilize power supply voltage and cope with high-frequency driving by an approach different from Patent Document 1. In providing equipment.

One embodiment of the present invention relates to a power converter. The power conversion device includes an upper power supply line, a lower power supply line, a plurality of high-side transistor units, and a plurality of low-side transistor units, each provided for each high-side transistor unit, and gated to the corresponding high-side transistor unit. Multiple high-side gate drive circuits that output drive signals, each provided for each low-side transistor unit, and multiple low-side gate drive circuits that output gate drive signals to the corresponding low-side transistor units, each of which is a high-side gate drive A plurality of high-side power supply circuits that are provided for each circuit and supply a power supply voltage to the corresponding high-side gate drive circuit, each provided for each low-side gate drive circuit, and corresponding low-side gate drive circuits And a plurality of low-side power supply circuit for supplying a power supply voltage to over preparative drive circuit.
The plurality of high-side transistor units are provided for each phase, and the control terminals are provided independently in parallel between the output terminals of the corresponding phases and the upper power supply lines. The plurality of low-side transistor units are provided for each phase, and the control terminals are provided independently in parallel between the output terminals of the corresponding phases and the lower power supply line.

  According to this aspect, the high-side transistor and the low-side transistor are each divided into a plurality of transistor units, and the gate drive circuit and the power supply circuit are divided and configured for each transistor unit, thereby providing a flexible layout as compared with the case where the transistor is not divided. Is possible. As a result, the impedance of the supply path (power supply line) of the power supply voltage supplied from the power supply circuit to the gate drive circuit can be reduced, and the power supply circuit is divided for each transistor unit, so the power supply voltage can be reduced even with a small smoothing capacitor. It becomes possible to stabilize, and as a result, it can respond to a high frequency drive.

Multiple high-side transistor units, multiple low-side transistor units, multiple high-side gate drive circuits, multiple low-side gate drive circuits, multiple high-side power supply circuits, and multiple low-side power supply circuits may be laid out on the same layer Good.
In this case, the power supply circuit corresponding to the gate drive circuit can be arranged adjacent to the same layer, and the power supply voltage can be supplied by a short wiring on the printed circuit board.

  The layer may be divided into a plurality of substrates. Each substrate has at least one set of a high-side transistor unit, a corresponding high-side gate drive circuit, a corresponding high-side power supply circuit, a low-side transistor unit, a corresponding low-side gate drive circuit, and a corresponding low-side power supply circuit. It may be mounted.

The layer may be divided into a plurality of substrates. Each substrate includes (1) a plurality of high-side transistor units in phase, a plurality of high-side gate drive circuits corresponding to them, a set of a plurality of high-side power supply circuits corresponding to them, and (2) a plurality of in-phase At least one of a low-side transistor unit, a plurality of low-side gate drive circuits corresponding to them, and a set of a plurality of low-side power supply circuits corresponding to them may be mounted.
When the substrate is divided into a plurality of parts, it can be increased or decreased, and the capacity of the power conversion device can be easily designed according to the load.

  The substrate may be a metal base substrate. Heat dissipation can be improved by using a metal base substrate.

The plurality of high-side transistor units, the plurality of low-side transistor units, the plurality of high-side gate drive circuits, and the plurality of low-side gate drive circuits are mounted on the first layer, and the plurality of high-side power supply circuits and the plurality of low-side power supply circuits are It may be mounted on the second layer. The low-impedance wiring that connects the first layer and the second layer is supplied from each high-side power supply circuit to the corresponding high-side gate drive circuit, and from each low-side power supply circuit to the corresponding low-side gate drive circuit. It may be supplied via. The high-side power supply circuit and the low-side power supply circuit may be arranged in the vicinity of the corresponding low-impedance wiring, respectively, and the high-side gate drive circuit and the low-side gate drive circuit may be arranged in the vicinity of the corresponding low-impedance wiring, respectively.
Even when the configuration is divided into two layers, the power supply voltage supply path, that is, the impedance of the power supply line can be reduced if the gate drive circuit and the power supply circuit are arranged at positions overlapping each other and connected by a low impedance wiring. Can be lowered.

  Due to the advantages of the above-described current converter, it can be suitably used for industrial vehicles. Therefore, in one aspect, the power conversion device may be mounted on a forklift and supply power to the motor.

  Note that any combination of the above-described constituent elements and the constituent elements and expressions of the present invention replaced with each other among methods, apparatuses, systems, and the like are also effective as an aspect of the present invention.

  According to the present invention, the power supply voltage can be stabilized and high frequency driving can be supported.

It is a circuit diagram of the layout of a general power converter (inverter). It is sectional drawing of the power converter device which the present inventors examined. It is an equivalent circuit diagram which shows the structure of the power converter device which concerns on embodiment. 4A to 4C are diagrams illustrating a layout of the power conversion device. FIGS. 5A and 5B are diagrams showing the configuration of the forklift. It is sectional drawing of the power converter device which concerns on a modification.

  The present invention will be described below based on preferred embodiments with reference to the drawings. The same or equivalent components, members, and processes shown in the drawings are denoted by the same reference numerals, and repeated descriptions are omitted as appropriate. The embodiments do not limit the invention but are exemplifications, and all features and combinations thereof described in the embodiments are not necessarily essential to the invention.

In this specification, “the state in which the member A is connected to the member B” means that the member A and the member B are electrically connected to each other in addition to the case where the member A and the member B are physically directly connected. It includes cases where the connection is indirectly made through other members that do not substantially affect the general connection state, or that do not impair the functions and effects achieved by their combination.
Similarly, “the state in which the member C is provided between the member A and the member B” refers to the case where the member A and the member C or the member B and the member C are directly connected, as well as their electric It includes cases where the connection is indirectly made through other members that do not substantially affect the general connection state, or that do not impair the functions and effects achieved by their combination.

  FIG. 3 is an equivalent circuit diagram showing a configuration of the power conversion device 2 according to the embodiment. The power conversion device 2 is mounted on an industrial vehicle such as a forklift, and drives a motor for cargo handling and a motor for wheels.

  The power conversion device 2 includes an upper power line LP, a lower power line LN, a plurality of high side transistor units mh, a plurality of low side transistor units ml, a plurality of high side gate drive circuits 10H, and a plurality of low side gates. A drive circuit 10L, a controller 12, a plurality of high-side power supply circuits 14H, a plurality of low-side power supply circuits 14L, and a main power supply circuit 16 are provided.

  In this embodiment, an example in which a three-phase motor is a load will be described, but the load is not particularly limited. Since the U phase, the V phase, and the W phase are configured in the same manner, the following description focuses on the U phase.

  A set of a plurality of high side transistor units mhu1 to mhu3 is provided for each phase. Each high-side transistor unit mhu is electrically provided in parallel and independently with a control terminal (gate, base) between the corresponding phase (U) output terminal OUTU and the upper power supply line LP. The high side transistor unit mh is configured by an IGBT (Insulated Gate Bipolar Transistor), an FET (Field Effect Transistor), a bipolar transistor, and the like. Each transistor is provided with a free-wheeling diode (also referred to as a flywheel diode or a freewheel diode).

  Similarly, a set of a plurality of low side transistor units mlu1 to mlu3 is provided for each phase. Each low-side transistor unit mlu is provided electrically in parallel and independently with a control terminal (gate, base) between the output terminal OUTU of the corresponding phase (U) and the lower power supply line LN. The number of transistor units in each phase is not limited to three, and may be determined according to the motor 4.

  The controller 12 generates control commands S1H and S1L for driving the high side transistor unit mh and the low side transistor unit ml. The main power supply circuit 16 generates a stabilized power supply voltage VDD. The power supply voltage VDD is supplied to the controller 12, and is also supplied to each of the plurality of high-side power supply circuits 14H and low-side power supply circuits 14L.

  The plurality of high-side gate drive circuits 10H_U1 to U3 are provided for the high-side transistor units mhu1 to mhu1 to 3 respectively. The i-th high-side gate drive circuit 10H_Ui outputs the gate drive signal S2H to the control terminal of the corresponding high-side transistor unit mhi in response to the control command S1H from the controller 12.

  The plurality of low side gate drive circuits 10L_U1 to U3 are provided for the low side transistor units mlu1 to mlu3, respectively. The i-th low-side gate drive circuit 10L_Ui outputs a gate drive signal S2L to the control terminal of the corresponding low-side transistor unit mlui in response to the control command S1L from the controller 12.

The high side power supply circuits 14H_U1 to U3 are provided for the high side gate drive circuits 10H_U1 to U3, respectively. The i-th high side power supply circuit 14H_Ui generates the power supply voltage VDDH_Ui to be supplied to the corresponding high side gate drive circuit 10H_Ui based on the power supply voltage VDD.
The low side power supply circuits 14L_U1 to U3 are provided for the low side gate drive circuits 10L_U1 to U3, respectively. The i-th low side power supply circuit 14L_Ui generates the power supply voltage VDDL_Ui to be supplied to the corresponding low side gate drive circuit 10L_Ui based on the power supply voltage VDD.

  The V phase and the V phase are similarly configured. The circuit configuration of the power conversion device 2 has been described above. Next, the layout will be described.

  4A to 4C are diagrams illustrating a layout of the power conversion device 2. FIG. FIG. 4A is a cross-sectional view of the power conversion device 2. The power conversion device 2 is composed of two layers. The controller 12 is mounted on the substrate of the second layer L2. The remaining units, that is, a plurality of high-side transistor units mh, a plurality of low-side transistor units ml, a plurality of high-side gate drive circuits 10H, a plurality of low-side gate drive circuits 10L, a plurality of high-side power supply circuits 14H, and a plurality of low-side power supply circuits 14L is laid out in the first layer L1. From the viewpoint of heat dissipation or the like, the substrate 18 of the first layer L1 is preferably a metal base substrate.

  The first layer L1 may be composed of a single substrate 18, but may be divided into a plurality of substrates 18. 4B and 4C are diagrams showing the layout of the divided substrate 18. In FIG. 4B, one substrate 18 has a high side transistor unit mh, a high side gate drive circuit 10H corresponding to the high side transistor unit mh, a high side power supply circuit 14H corresponding to the high side transistor drive unit 10H, and a low side transistor unit that forms a pair with the high side transistor mh. ml, a corresponding low-side gate drive circuit 10L, and a corresponding low-side power supply circuit 14L are mounted. A plurality of sets may be mounted on one substrate 18. For example, three high-side transistor units mh, three low-side transistor units ml having the same phase, a gate drive circuit corresponding to them, and a power supply circuit may be mounted on one substrate 18.

  In FIG. 4C, one substrate 18 includes (1) a plurality of high-side transistor units mh in phase, a plurality of high-side gate drive circuits 10H corresponding to them, and a plurality of high-side power supply circuits corresponding to them. A 14H set is installed. Alternatively, (1) a set of a plurality of low-side transistor units ml in phase, a plurality of low-side gate drive circuits 10L corresponding to them, and a plurality of low-side power supply circuits 14L corresponding to them are mounted on one substrate 18.

  When the number of in-phase low-side transistor units ml is large, the substrate 18 in FIG. 4C may be further divided.

The above is the configuration of the power conversion device 2 according to the embodiment.
In the power conversion device 2, the high-side transistor and the low-side transistor are each divided into a plurality of transistor units mh and ml, and the high-side gate drive circuit 10H and the low-side gate drive circuit 10L are divided into a plurality for each transistor unit mh and ml. The high side power supply circuit 14H and the low side power supply circuit 14L are also divided into a plurality of parts. As a result, a flexible layout is possible as compared with the case of not dividing, and as shown in FIG. 4A, power supply voltages VDDH_U1 to U3 supplied from the high side power supply circuits 14H_U1 to U3 to the high side gate drive circuits 10H_U1 to U3. The impedance of each power line can be reduced. Similarly, the impedances of the power supply lines of the power supply voltages VDDL_U1 to U3 supplied from the low side power supply circuits 14L_U1 to U3 to the low side gate drive circuits 10L_U1 to U3 can be reduced. As a result, even with a small smoothing capacitor, the power supply voltages VDDH_U1 to U3 and VDDL_U1 to U3 can be stabilized, and as a result, high frequency driving can be supported. The same applies to the V phase and the W phase.

  Further, since the power supply circuit 14 is divided for each transistor unit, the power consumption of each power supply circuit 14 can be greatly reduced as compared with the configuration of FIG. 1, and heat generation can be distributed. Thereby, the large heat sink required in the configuration of FIG. 1 can be reduced in size or eliminated.

  Moreover, since it is divided into a plurality of transistor units, the switching noise generated in each transistor unit can be made smaller than when it is not divided. Therefore, compared with the technique described in Patent Document 1, malfunction due to noise can be suppressed.

  Further, since the three-layer structure in FIG. 2 becomes a two-layer structure, resistance to vibration can be increased. In addition, since most units other than the controller 12 and the main power supply circuit 16 are mounted on the bottom layer, the center of gravity can be lowered and the resistance to vibration can be increased.

  Then, the use of the above-mentioned power converter 2 is explained. With the above-described advantages, the power conversion device 2 can satisfy the specifications required for industrial vehicles. For example, the power conversion device 2 can be suitably used for a forklift that requires high frequency and vibration resistance.

  FIGS. 5A and 5B are diagrams showing the configuration of the forklift. As shown in FIG. 5A, the forklift 1 includes a main body 60, a fork 62, an elevating body 64, a mast 66, and wheels 68. The mast 66 is provided on all sides of the main body 60. The elevating body 64 is driven by a power source such as a hydraulic pump (not shown) and moves up and down along the mast 66. A fork 62 for supporting a load is attached to the elevating body 64.

  FIG. 5B is a diagram illustrating a configuration of the electric system of the forklift 1. The forklift 1 includes two systems of motors M1 and M2. The first motor M1 is a wheel motor for rotating the wheels 68, and the second motor M2 is a cargo handling motor for controlling a hydraulic actuator that raises and lowers the elevating body 64. Each of the power conversion devices 2_1 and 2_2 receives a DC voltage from the battery 80, converts it into a three-phase AC signal, and supplies it to the corresponding motors M1 and M2. The battery 80, the power conversion devices 2_1 and 2_2, and the motors M1 and M2 are fixed to the main body 60. The power conversion devices 2_1 and 2_2 may be separate modules or may be configured as a single module.

  The power converter described above can be suitably used for such a forklift 1 in view of its vibration resistance, high-frequency surge resistance, and the like.

  In the embodiment, the power conversion device 2 that drives a three-phase motor has been described. However, the present invention is not limited to a three-phase motor, and can be applied to a DC motor or a multiphase motor. In the embodiment, the case where the motor 4 is directly connected to the power conversion device 2 has been described. However, another conversion device or other circuit block is inserted between the power conversion device 2 and the motor 4. It may be.

  In the above, this invention was demonstrated based on the Example. It will be understood by those skilled in the art that the present invention is not limited to the above-described embodiment, and various design changes are possible, various modifications are possible, and such modifications are within the scope of the present invention. By the way. Hereinafter, such modifications will be described.

FIG. 6 is a cross-sectional view of a power conversion device 2a according to a modification. In this modification, the high-side power supply circuit 14H and the low-side power supply circuit 14L are laid out in the second layer L2.
The power supply voltage VDDH from each high side power supply circuit 14H to the corresponding high side gate drive circuit 10H, and the power supply voltage VDDL from each low side power supply circuit 14L to the corresponding low side gate drive circuit 10L are the first layer L1. And the second layer L2 is supplied via a low impedance wiring 40. As the low impedance wiring 40, a low impedance conductor having a large cross-sectional area such as a bus bar, a pin, a lead, a connector, or a cable can be used.

  Each of the high-side power supply circuit 14H and the low-side power supply circuit 14L is disposed in the vicinity of the corresponding low impedance wiring 40. Further, the high side gate drive circuit 10H and the low side gate drive circuit 10L are also arranged in the vicinity of the corresponding low impedance wiring 40, respectively. From the viewpoint of layout efficiency, it is desirable that the corresponding high-side gate drive circuit 10H and high-side power supply circuit 14H be arranged to at least partially overlap each other. The same applies to the corresponding low-side gate drive circuit 10L and low-side power supply circuit 14L.

  According to this modification, by using a conductor having a lower impedance than the wiring on the printed circuit board as the power supply line, the impedance of the power supply lines of the power supply voltages VDDH and VDDL can be reduced as in the layout of FIG. Can be lowered.

DESCRIPTION OF SYMBOLS 1 ... Forklift, 2 ... Power converter device, 4 ... Motor, 6 ... Power supply, 10H ... High side gate drive circuit, 10L ... Low side gate drive circuit, 12 ... Controller, 14H ... High side power supply circuit, 14L ... Low side power supply circuit, DESCRIPTION OF SYMBOLS 16 ... Main power supply circuit, 18 ... Board | substrate, 30 ... Controller card, 32 ... Gate drive card, 34 ... Output stage card, 36 ... Control signal pin, 40 ... Low impedance wiring, mh ... High side transistor unit, ml ... Low side transistor Unit, LP ... upper power supply line, LN ... lower power supply line, S1 ... control command, S2 ... gate drive signal.

Claims (7)

An upper power line;
The lower power line,
A plurality of high-side transistor units provided for each phase, electrically connected in parallel between the corresponding phase output terminal and the upper power supply line, and independently provided with a control terminal;
A plurality of low-side transistor units provided for each phase, electrically connected in parallel between the output terminal of the corresponding phase and the lower power supply line, and independently provided with a control terminal;
A plurality of high-side gate drive circuits each provided for each of the high-side transistor units and outputting a gate drive signal to the corresponding high-side transistor unit;
A plurality of low-side gate drive circuits each provided for each low-side transistor unit and outputting a gate drive signal to the corresponding low-side transistor unit;
A plurality of high-side power supply circuits, each provided for each of the high-side gate drive circuits, for supplying a power supply voltage to the corresponding high-side gate drive circuit;
A plurality of low-side power supply circuits, each provided for each low-side gate drive circuit, for supplying a power supply voltage to the corresponding low-side gate drive circuit;
A power conversion device comprising:   The plurality of high-side transistor units, the plurality of low-side transistor units, the plurality of high-side gate drive circuits, the plurality of low-side gate drive circuits, the plurality of high-side power supply circuits, and the plurality of low-side power supply circuits are the same The power conversion device according to claim 1, wherein the power conversion device is laid out in a layer. The layer is divided into a plurality of substrates,
Each substrate has at least one set of a high-side transistor unit, a corresponding high-side gate drive circuit, a corresponding high-side power supply circuit, a low-side transistor unit, a corresponding low-side gate drive circuit, and a corresponding low-side power supply circuit. The power converter according to claim 2, wherein the power converter is mounted. The layer is divided into a plurality of substrates,
Each substrate includes (1) a plurality of high-side transistor units, a plurality of high-side gate drive circuits corresponding to them, a set of a plurality of high-side power supply circuits corresponding to them, and (2) a plurality of low-side transistor units, The power converter according to claim 2, wherein at least one of a plurality of low-side gate drive circuits corresponding to them and a set of a plurality of low-side power supply circuits corresponding to them is mounted.   The power converter according to claim 3 or 4, wherein the substrate is a metal base substrate. The plurality of high side transistor units, the plurality of low side transistor units, the plurality of high side gate drive circuits, and the plurality of low side gate drive circuits are mounted on a first layer,
The plurality of high-side power supply circuits and the plurality of low-side power supply circuits are mounted on a second layer,
The power supply voltage from each high-side power supply circuit to the corresponding high-side gate drive circuit and the power supply voltage from each low-side power supply circuit to the corresponding low-side gate drive circuit are low, respectively, connecting the first layer and the second layer. Supplied through impedance wiring,
The high side power supply circuit and the low side power supply circuit are each disposed in the vicinity of the corresponding low impedance wiring,
The power converter according to claim 1, wherein each of the high-side gate drive circuit and the low-side gate drive circuit is disposed in the vicinity of the corresponding low-impedance wiring.   The power conversion apparatus according to claim 1, wherein the power conversion apparatus is mounted on a forklift and supplies electric power to a motor.

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