JP5985700B2 - Motor drive device for vehicle drive wheel - Google Patents

Description

  The present invention relates to a motor drive device for drive wheels of a vehicle such as an electric vehicle, a fuel cell vehicle, and a hybrid vehicle in which an in-wheel motor is disposed on at least two of the plurality of drive wheels.

  In an in-wheel motor vehicle such as an electric vehicle, a fuel cell vehicle, and a hybrid vehicle in which an in-wheel motor is disposed on at least two of the plurality of driving wheels, an inverter unit and an inverter control are used to control the in-wheel motor. The motor drive device which consists of a part is required. FIG. 29 shows a conventional example of a four-wheel drive in-wheel motor vehicle 31 in which in-wheel motor portions 33A to 33D are arranged on front left and right wheels 32A and 32B and rear left and right wheels 32C and 32D, respectively. The motor driving devices 34A to 34D corresponding to the in-wheel motor units 33A to 33D are separately disposed at positions closest to the in-wheel motor units 33A to 33D. Direct current power is supplied from the battery 35 through the battery control unit 36 to each of the motor drive devices 34A to 34D. Each of the motor driving devices 34A to 34D may be separately provided with a booster circuit to increase the power supply voltage from the battery 35 in order to improve driving efficiency.

  2. Description of the Related Art Conventionally, a configuration example has been proposed in which a cooler that cools an inverter unit in a motor drive device of a vehicle is capable of absorbing energy in the event of a collision (Patent Document 1). In this configuration example, a motor driving device is disposed on one side of the cooler, and a smoothing capacitor and a DC / DC converter are disposed on the other side.

  Further, as another conventional example of a vehicle motor drive device, a plurality of control units provided in the motor drive device are arranged on both sides of the cooler, and the cooler has a capacity smaller than the total value of the heat generation amount of each control unit. A configuration example using a device has also been proposed (Patent Document 2). In this document, an air conditioner inverter and a DC / DC converter are cited as specific examples of the control unit disposed on both sides of the cooler.

  As another conventional example, various inverter units, capacitors, and high voltage converters that are components of the motor drive device are arranged on the upper surface of the component arrangement plate, and a control unit corresponding to the inverter unit is arranged on the lower surface of the component arrangement plate. A configuration example in which a reactor for a high-voltage converter, a DC / DC converter, and a low-voltage component are arranged has been proposed (Patent Document 3).

JP-A-6-303704 JP 7-67213 A JP-A-2005-57928

However, as in the conventional example of FIG. 29, a space is required to mount the plurality of motor drive devices 34A to 34D and the booster circuit, which causes an increase in weight and cost.
The configuration example disclosed in Patent Document 1 is for a single motor drive device, and does not assume a case where a plurality of motor drive devices are mounted as in an in-wheel motor vehicle.

  In the configuration example disclosed in Patent Document 2, a plurality of control units are arranged on both sides of the cooler. As specific examples of the control unit, only an air conditioner inverter and a DC / DC converter are listed. Depending on the combination of multiple control units, it can be expected that a different effect can be obtained. However, this document mentions even the case of an in-wheel motor vehicle having a plurality of motor drive devices and boosting circuits. Absent.

  In the configuration example disclosed in Patent Document 3, there is a possibility that the total volume of the drive device may be reduced. However, a large plane space is required in the vehicle, the space that can be arranged is limited, and the degree of freedom in arrangement is small. . In addition, since the inverter unit is arranged on the upper surface of the component arrangement plate and the control unit is arranged on the lower surface, the configuration is complicated.

  Thus, since an in-wheel motor vehicle is equipped with a plurality of motor drive devices and booster circuits, a space is required for this purpose, and there is a concern about an increase in weight and an increase in cost. However, the configuration examples disclosed in Patent Documents 1 to 3 cannot solve this problem.

The purpose of the present invention is to provide a smaller, lighter, and the motor drive equipment for driving wheels of the cost reduction possible vehicles.

A motor driving device for driving wheels of a vehicle according to the present invention includes a plurality of in-wheel motor units respectively disposed on at least two driving wheels among a plurality of driving wheels of the vehicle, and a plurality for controlling each of the in-wheel motor units. The motor drive device includes a smoothing circuit that has a smoothing capacitor and smoothes DC power supplied from the battery unit, and a plurality of drive elements that perform a switching operation, and passes through the smoothing circuit. For a drive wheel of a vehicle having an inverter unit that converts input DC power into three-phase AC by intermittent connection of the drive element, an inverter control unit that controls the inverter unit, and a cooler that cools the inverter unit In the motor drive device,
The plurality of motor drive devices are arranged in the same case, and the plurality of motor drive devices share the smoothing capacitor that is a component of these motor drive devices with each other, and the inverter control unit includes the inverter unit. A calculation unit having a function of determining an on / off timing of the drive element in the motor and controlling a torque or a rotation speed of the motor of the in-wheel motor unit, and the drive element in the inverter unit according to a command from the calculation unit A driving element pre-driver circuit for controlling on / off of the driving element, wherein the plurality of motor driving devices share the arithmetic unit of the inverter control unit, and the driving element pre-driver circuit is connected to each inverter. provided separately to the control unit, said inverter control unit of the plurality of motor drive, the drive of the inverter unit A control system for driving the element in the PWM method, the plurality of motor drive, the period of the PWM is equal and is characterized by shifting the on-off timing of the drive element to each other to each other.
According to this configuration, since the plurality of motor driving devices are collected in one place and arranged in the same case, it is possible to share the component parts and the accompanying components among the plurality of motor driving devices. For example, as described above, the smoothing capacitor of the smoothing circuit can be shared by a plurality of motor driving devices. In addition, it is possible to share the arithmetic unit of the inverter control unit among a plurality of motor driving devices. For this reason, the drive device can be reduced in size, weight, and cost.
Moreover, since the calculation unit of each inverter control unit is shared by one, information on the state (rotation speed, current value, temperature, etc.) of the in-wheel motor unit and the motor drive device can be easily obtained without using communication. Can be shared.

  In the present invention, there is a boosting unit that boosts the supply voltage from the power source. These boosting units are composed of a boosting control unit, a driving element, a reactor, and a rectifier, and the boosting unit is disposed in the same case. Also good. By disposing the boosting unit in the same case, the cooling unit can be shared, and further miniaturization, weight reduction, and cost reduction are possible.

  A plurality of motor drive devices arranged in the same case may share one smoothing circuit as the smoothing circuit. Moreover, the several motor drive device arrange | positioned in the said same case may share one cooler as said cooler. Since a plurality of motor drive devices are provided in the same case, the current to the plurality of motor drive devices can be smoothed by one smoothing circuit, and the plurality of motor drive devices can be cooled by one cooler. Can do.

  The cooler may be a water cooling system. The water cooling method has better cooling efficiency than the air cooling method. In the case of the water cooling method, a circulation system for the refrigerant is required. However, since a plurality of motor drive devices are arranged in the same case, an increase in cost due to the circulation system can be suppressed.

In the present invention, the cooler has both sides facing away from each other as cooling surfaces, and a motor drive device body, which is a part constituted by the inverter unit and inverter control unit of the motor drive device, is arranged on both surfaces. Inverter units may be positioned on both sides of the cooler.
Thus, when each motor drive device main body is divided and arranged on both sides of the cooler, the cooler can be reduced in size and the cooling efficiency of the cooler can be improved. As a result, the drive device can be reduced in size, weight, and cost.

A motor drive device main body that is a portion excluding the cooler in the motor drive device may be arranged on one surface side of the cooler, and the inverter unit may be positioned on the one surface side of the cooler.
In this case, each of the motor driving devices has a boosting unit that boosts the supply voltage from the power source. These boosting units are composed of a boosting control unit, a driving element, a reactor, and a rectifier, and the coolers are mutually connected. Both surfaces facing backwards are cooling surfaces, the boosting unit is disposed on the other side of the surface of the cooler where the inverter unit is disposed, and the drive element of the boosting unit is positioned on the other surface side You may let them.
Thereby, both the inverter and the drive element of the step-up unit can be efficiently cooled using the cooling surfaces on both sides of the cooler.

In this invention, you may integrate the said inverter control part of these motor drive devices so that at least one part may be shared mutually. For example, the inverter control unit may include a first calculation unit, and the plurality of inverter control units may share the first calculation unit.
By integrating the inverter control unit, the communication cables, harnesses, and connectors can be used in common, so that the size and cost can be reduced.

  Each of the motor driving devices has a boosting unit that boosts a supply voltage from a power source. These boosting units include a boosting control unit, a driving element, a reactor, and a rectifier. The plurality of motor driving devices are The inverter control unit and the boosting control unit of the boosting unit may be integrated so that at least a part is shared among a plurality of motor driving devices. In this case, the boosting control unit includes a second calculation unit, and by sharing the first calculation unit of the inverter control unit and the second calculation unit of the boosting control unit, The inverter control unit and the boost control unit may be integrated. By sharing the calculation unit, information such as the state of the motor and motor drive device (rotation speed, current value, temperature, etc.) can be easily shared without using a long communication path. Simplified.

More specifically, the present invention is a control method in which the inverter control unit of the plurality of motor drive devices is a control method for driving the drive element of the inverter unit by a PWM (pulse width modulation) method, and the plurality of motors The drive devices have the same PWM period and shift the on / off timings of the drive elements from each other.
When the inverter control units of a plurality of motor drive devices are integrated, the ripple current to the smoothing circuit can be reduced by shifting the on / off timing of the drive elements. By sharing the calculation unit, it is possible to easily control the drive element ON timing of a plurality of motor drive devices, and thus the timing can be shifted in this way.
The inverter control unit has a function of determining the on / off timing of the drive element in the inverter unit and controlling the torque or rotation speed of the motor of the in-wheel motor unit, and a command from the calculation unit And a drive element pre-driver circuit for controlling on / off of the drive element in the inverter unit, and the plurality of motor drive devices share the calculation unit of the inverter control unit with each other. Also good.
By sharing the arithmetic unit, it is possible to easily control the drive element ON timing of a plurality of motor drive devices, and thus the timing can be shifted as described above.

When the on / off timing is shifted, the plurality of motor drive devices have equal intervals between the centers of the on-timing of the drive elements of the inverter unit of each motor drive device by dividing the PWM cycle by the number of motor drive devices. It may be shifted as follows.
Further, the plurality of motor drive devices may be shifted so that the start of the drive element on-timing of the inverter unit of each motor drive device is equally spaced by dividing the PWM cycle by the number of motor drive devices.
By shifting at regular intervals as described above, the peak value of the ripple current from the shared smoothing capacitor can be reduced, and the smoothing capacitor can be miniaturized.

In the case of shifting the on / off timing, in the two-wheel drive, the motor driving device may shift the on / off timing of the drive element of the inverter unit by 180 degrees with respect to each other in the PWM cycle. In the four-wheel drive, the motor drive device may shift the on / off timing of the drive element of the inverter unit by 90 degrees with respect to each other in the PWM cycle. In the eight-wheel drive, the motor drive device may shift the on / off timing of the drive element of the inverter unit by 45 degrees in the PWM cycle.
As described above, in the four-wheel drive, when one cycle of the PWM control is divided into four and control is performed so that the center of the on-operation time of each drive device comes at an interval of 90 degrees, the load is instantaneously increased from the battery at low load. It is not necessary to supply current, and the current is smoothed. Similarly to the above, by shifting 180 degrees in the two-wheel drive and 45 degrees in the eight-wheel drive, it is not necessary to instantaneously supply a large current from the battery at a low load, and the current is smoothed.
The two-wheel drive, four-wheel drive, and eight-wheel drive are not limited to the case where the number of wheels having an in-wheel motor section is two wheels, four wheels, and eight wheels, respectively. If possible, control may be performed so that the above-described shift angle is obtained in a state where switching is made to two-wheel drive, four-wheel drive, and eight-wheel drive.

As described above, when the first calculation unit of the inverter control unit and the second calculation unit of the boosting control unit are integrated, the boosting control unit of the boosting unit PWMs a plurality of drive elements. It is also possible to drive by the same method, equalize the PWM periods of the plurality of drive elements, and shift the on / off timing of each drive element.
When the arithmetic units are integrated in this way, the ripple current to the smoothing circuit can be reduced even if the on / off timings of the plurality of drive elements of the booster unit are shifted.

When shifting the on / off timings of a plurality of drive elements in the boost unit, the boost control unit of the boost unit divides the PWM cycle by the number of drive elements at the center of the on / off timing of each drive element. May be shifted so as to be equally spaced.
The start of the on / off timing may be shifted instead of the center of the on / off timing. In other words, the boosting control unit of the boosting unit may shift the start of the on / off timing of each drive element so that the PWM cycle is divided by the number of drive elements so as to be equally spaced.

  When shifting the on / off timings of the plurality of drive elements of the boost unit, the boost control unit of the boost unit may control so that all the on timings of the plurality of drive elements do not overlap.

When the inverter control unit and the boost control unit of the boost unit are integrated so that at least a part is shared among a plurality of motor driving devices, the boost control unit of the boost unit is The drive elements may be driven by the PWM method, and the PWM period of the plurality of drive elements may be variable.
In this case, the boosting control unit of the boosting unit may drive all of the plurality of drive elements in the same cycle.

The boosting control unit of the boosting unit may fix the PWM on / off ratio and make the PWM cycle variable.
In this case, the boosting control unit of the boosting unit fixes the PWM ON ratio of the plurality of driving elements so as to be an interval obtained by dividing the PWM cycle by the number of the plurality of driving elements, and It may be shifted so that the on-timing does not overlap.
Further, the boosting control unit of the boosting unit fixes the PWM OFF ratio of the plurality of driving elements so as to be an interval obtained by dividing the PWM cycle by the number of the plurality of driving elements, and turns on the timing of each driving element. It may be shifted so as not to overlap.

The boosting unit may have a plurality of driving elements and a plurality of reactors with respect to one boosting control unit. The boosting unit may be driven such that the operation start times and operation stop times of the plurality of drive elements are different from each other.
The boosting unit has a plurality of reactors, and by shifting the timing of current application to each reactor, the ripple current of the smoothing circuit can be reduced, and the capacitor of the smoothing circuit can be reduced in size. By using multiple reactors, the reactor can be downsized. As a result, the motor drive device for the drive wheels of the vehicle can be further reduced in size, weight, and cost.

  The boosting unit may set intervals between operation start times of the plurality of driving elements. The boosting unit may be configured not to overlap the operation times of a plurality of driving elements. This also reduces the ripple current.

  In addition, as described above, when the boosting unit has a plurality of driving elements and a plurality of reactors with respect to one boosting control unit, the boosting unit has a bypass path that supplies current without passing through the reactor. Also good. In the boosting unit, the boosting voltage is determined according to the rotation speed of the in-wheel motor unit. That is, when the rotational speed is lower than a predetermined value, the boosting operation is not performed. If there is no bypass path in the boosting section, even if the boosting operation is not performed, a current is supplied from the power source via the reactor, so that the loss due to the resistance of the reactor cannot be ignored. Therefore, by providing a bypass path in the boosting section, it is possible to reduce the loss during low-speed operation.

The vehicle may be an electric vehicle or a fuel cell vehicle in which one of the front left and right wheels and the rear left and right wheels is driven by the in-wheel motor unit. Further, the vehicle may be a hybrid vehicle in which one of the front left and right wheels and the rear left and right wheels is driven by the in-wheel motor unit, and the other is driven by an internal combustion engine. The vehicle may be an electric vehicle or a fuel cell vehicle in which both the front left and right wheels and the rear left and right wheels are driven by the in-wheel motor unit.
Since the in-wheel motor vehicle of the present invention is equipped with the motor drive device for the drive wheels of the vehicle of the present invention, it is possible to reduce the size, weight, and cost of the device that drives the in-wheel motor. Become.

A motor driving device for driving wheels of a vehicle according to the present invention includes a plurality of in-wheel motor units respectively disposed on at least two driving wheels among a plurality of driving wheels of the vehicle, and a plurality for controlling each of the in-wheel motor units. The motor drive device includes a smoothing circuit that has a smoothing capacitor and smoothes DC power supplied from the battery unit, and a plurality of drive elements that perform a switching operation, and passes through the smoothing circuit. Driving an in-wheel motor vehicle having an inverter unit that converts input DC power into three-phase AC by intermittently driving the drive element, an inverter control unit that controls the inverter unit, and a cooler that cools the inverter unit In the motor drive device for wheels,
The plurality of motor drive devices are arranged in the same case, and the plurality of motor drive devices share the smoothing capacitor that is a component of these motor drive devices with each other, and the inverter control unit includes the inverter unit. A calculation unit having a function of determining an on / off timing of the drive element in the motor and controlling a torque or a rotation speed of the motor of the in-wheel motor unit, and the drive element in the inverter unit according to a command from the calculation unit A driving element pre-driver circuit for controlling on / off of the driving element, wherein the plurality of motor driving devices share the arithmetic unit of the inverter control unit, and the driving element pre-driver circuit is connected to each inverter. provided separately to the control unit, said inverter control unit of the plurality of motor drive, the drive of the inverter unit This is a control method for driving an element by a PWM method, and the plurality of motor driving devices have the same PWM cycle and the on / off timings of the driving elements are shifted from each other. Can be realized.
Moreover, since the calculation unit of each inverter control unit is shared by one, information on the state (rotation speed, current value, temperature, etc.) of the in-wheel motor unit and the motor drive device can be easily obtained without using communication. Can be shared.

It is the schematic which shows the arrangement configuration of the component in the in-wheel motor vehicle carrying the drive device concerning one Embodiment of this invention. It is the schematic which shows the circuit structural example of the motor drive device in the drive device which concerns on a reference proposal example. It is the schematic which shows the other circuit structural example of the motor drive device in the drive device of the embodiment. It is a front view which shows an example of the arrangement structure of the several motor drive apparatus main-body part and cooler in the same case in the drive device. It is a front view which shows the other example of arrangement | positioning structure of several motor drive device main-body part and a cooler in the same case in the drive device. It is a block diagram which shows the example of arrangement structure which integrated the control part of the several motor drive device. It is a block diagram which shows the structural example which shared the calculating part of the control part of the several motor drive unit by one thing. It is a wave form diagram which shows the voltage current waveform at the time of the motor drive of the motor drive device. (A) is an example of ON timing of the motor drive device, (B) is another example of ON timing, and (B) is a waveform diagram of still another example of ON timing. It is the schematic which shows the arrangement configuration of the component in the in-wheel motor vehicle carrying the drive device concerning other embodiment of this invention. It is the schematic which shows the circuit structure which added the pressure | voltage rise part to the motor drive device in the drive device. It is a front view which shows an example of arrangement | positioning structure of each motor drive device main-body part, a cooler, and a pressure | voltage rise part in the same case in the drive device. It is a front view which shows the example which integrated the control part of each motor drive device in the drive device. It is the schematic which shows an example of the circuit structure of the pressure | voltage rise part in the drive device. (A) is a waveform diagram of an example of timing of ON operation of the booster, (B) is a waveform diagram of the rectifier current, and (C) is a waveform diagram of the capacitor ripple current. (A) is a waveform diagram of an example of timing when the ON time of the boosting unit on operation is extended, (B) is a waveform diagram of the rectifier current, and (C) is a waveform diagram of the capacitor ripple current. It is a wave form chart of the other timing example of the ON operation of the boosting part. FIG. 10 is a waveform diagram of still another timing example of the ON operation of the boosting unit. (A) is a waveform diagram of still another timing example of the ON operation of the booster, (B) is a waveform diagram of the rectifier current, and (C) is a waveform diagram of the capacitor ripple current. (A) is a waveform diagram of still another timing example of the ON operation of the booster, (B) is a waveform diagram of the rectifier current, and (C) is a waveform diagram of the capacitor ripple current. (A) is a waveform diagram of still another timing example of the ON operation of the booster, (B) is a waveform diagram of the rectifier current, and (C) is a waveform diagram of the capacitor ripple current. It is the schematic which shows the other example of the circuit structure of the pressure | voltage rise part in the drive device. It is the schematic which shows the arrangement configuration of the component in an example of the in-wheel motor vehicle to which this invention is applied. It is the schematic which shows the arrangement configuration of the component in the other example of the in-wheel motor vehicle to which this invention is applied. It is the schematic which shows the arrangement configuration of the component in the further another example of the in-wheel motor vehicle to which this invention is applied. It is the schematic which shows the general circuit structure of a motor drive device. It is the schematic which shows the general circuit structure of a pressure | voltage rise part. It is a wave form diagram which shows the capacitor ripple current in the same step-up part. It is the schematic which shows the arrangement configuration of the component in the in-wheel motor vehicle carrying the conventional drive device.

An embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows a schematic diagram of the arrangement of component parts in an in-wheel motor vehicle equipped with the drive device of this embodiment. This in-wheel motor vehicle 1 has in-wheel motor portions 3A, 3B, 3C, and 3D arranged on front left and right wheels 2A and 2B and rear left and right wheels 2C and 2D as drive wheels, respectively, and these in-wheel motor portions 3A. All wheels are driven in 3D, for example, an electric vehicle or a fuel cell vehicle. The in-wheel motor units 3A to 3D are constituted by, for example, a motor, a speed reducer that decelerates the rotation of the motor, and a wheel bearing, and a part or all of them are arranged in the wheels 2A to 2D. Four motor drive devices 4A, 4B, 4C and 4D are provided in association with each in-wheel motor unit 3A to 3D, and rotation control of each in-wheel motor unit 3A to 3D is performed by these motor drive devices 4A to 4D. It is. Power is supplied from the battery 5 via the battery control unit 6 to the motor drive devices 4A to 4D.
In addition, in each said code | symbol 2A-2D, 3A-3D, 4A-4D etc., especially when distinction is not required, the character of A-D following a number may be abbreviate | omitted. Also for each of the symbols described later, the letters A to D following the numbers may be omitted if no particular distinction is necessary.

  The four motor driving devices 4 </ b> A to 4 </ b> D are collected in one place and arranged in the same case 7. FIG. 2 shows a schematic diagram of a circuit configuration of the motor driving devices 4A to 4D according to the reference proposal example. In the figure, the battery 5 and the battery control unit 6 are shown as a single battery block for simplicity. The motor 17 of the in-wheel motor units 3A to 3D is a synchronous motor including, for example, a stator 17a having a UVW three-phase coil and a rotor 17b made of a permanent magnet. The motor driving devices 4 </ b> A to 4 </ b> D include a main body unit 10 including a smoothing circuit 11, an inverter control unit 12, and an inverter unit 13, and a cooler 14 that cools the inverter unit 13. Here, a water-cooling type is used as the cooler 14, and a pump for circulating the refrigerant and a cooling unit (both not shown) for cooling the refrigerant are disposed outside the case 7. The DC power supplied from the battery unit is smoothed by the smoothing circuit 11 and input to the inverter unit 13. In motor drive devices 4A-4D, in order to control a large current when driving in-wheel motor units 3A-3D, a smoothing circuit 11 including a smoothing capacitor C is required at the input stage. The inverter unit 13 includes a plurality of drive elements 15 such as switching transistors, and converts DC power input through the smoothing circuit 11 into three-phase AC power by intermittent control of the drive element 15 by the inverter control unit 12. To the in-wheel motor units 3A to 3D. In the inverter control unit 12, the intermittent control timing of the drive element 15 of the inverter unit 13 is determined based on the rotational phase of the motor rotor 17 detected by the phase detector 16 in the in-wheel motor units 3 </ b> A to 3 </ b> D. The inverter control unit 12 also has a function of communicating with the motor drive devices 4A to 4D, or communicating with a host controller that is disposed in the vehicle and controls each electrical device of the vehicle.

  In FIG. 2 showing the reference proposal example, the smoothing circuit 11 is provided by providing separate smoothing capacitors C on the input side of the main body 10 of each of the motor driving devices 4A to 4D. In this embodiment, as shown in FIG. By providing a smoothing capacitor C on the input side of these motor driving devices 4A to 4D, one smoothing circuit 11 shared by the motor driving devices 4A to 4D is provided.

  FIG. 4 is a front view showing an example of the arrangement configuration of the main body 10 and the cooler 14 of each of the motor driving devices 4A to 4D in the case 7. The cooler 14 has a plate shape or a thin box shape, and both surfaces facing away from each other serve as a cooling surface 14a. In this arrangement configuration example, all of the main body portions 10 of the motor drive devices 4A to 4D are arranged on one side of one cooler 14 so that the inverter portions 13 are positioned close to the cooling surface of the cooler 14. Thus, one cooler 14 is shared by the motor driving devices 4A to 4D. The main body 10 of each of the motor driving devices 4 </ b> A to 4 </ b> D and the smoothing capacitor C constituting the smoothing circuit 11 are connected via a copper bar 18.

  In FIG. 4, all of the main body portions 10 of the motor driving devices 4 </ b> A to 4 </ b> D are arranged on one side of the cooler 14. However, as shown in FIG. The main body portions 10 of the motor driving devices 4A to 4D may be arranged separately on both sides of one cooler 14 so as to be in the above positions.

In the conventional driving device for an in-wheel motor vehicle, as shown in FIG. 29, motor driving devices 34A to 34D corresponding to the in-wheel motor units 33A to 33D are provided for each in-wheel motor unit 33A to 33D. Since they are separated from each other in the nearest position or in the nearest vehicle, it is necessary to provide the smoothing circuit 41 individually for each of the motor drive devices 34A to 34D as shown in FIG.
On the other hand, in the drive device of the in-wheel motor vehicle 1 of this embodiment, since all the motor drive devices 4A to 4D are collected in one place and arranged in the same case 7, one smoothing circuit 11 is connected to all the motors. A configuration shared by the driving devices 4A to 4D is possible. Further, as in the arrangement configuration examples of FIGS. 4 and 5, the main body 10 of all the motor drive devices 4 </ b> A to 4 </ b> D can be mounted on one cooler 14, so that one cooler 14 is shared. And the inverter part 13 of each motor drive device 4A-4D can be cooled. As shown in FIG. 5, when the main body portions 10 of the motor drive devices 4 </ b> A to 4 </ b> D are arranged separately on both sides of the cooler 14, the cooler 14 can be reduced in size, and further the cooling efficiency of the cooler 14. Can also be improved. As a result, the drive device can be reduced in size, weight, and cost.

  FIG. 6 shows an example of the arrangement configuration of FIG. 4 in which the main body 10 of each motor driving device 4A to 4D is arranged on one side of one cooler 14, and the inverter control units 12A to 12D of each motor driving device 4A to 4D are integrated. An example is shown in a block diagram. The inverter control units 12A to 12D are composed of a microcomputer, an electronic circuit, or the like. Each of the inverter control units 12A to 12D includes a first calculation unit 22, a sensor circuit 23, and a drive element pre-driver circuit 24, respectively. The calculation unit 22 determines the on / off timing of the drive element 15 in the inverter unit 13 and controls the motor torque or the rotation speed in the corresponding in-wheel motor units 3A to 3D, the fail-safe function, the communication mechanism, the temperature Responsible for monitoring functions. The sensor circuit 23 calculates the rotation angle from the signal of the phase detector 16 such as a resolver attached to the corresponding in-wheel motor units 3A to 3D. The drive element pre-driver circuit 24 controls on / off of the drive element 15 in the inverter unit 13 in accordance with a command from the calculation unit 22.

  As described above, the inverter control units 12A to 12D of the motor drive devices 4A to 4D communicate with each other, or are arranged in the vehicle and supervise and control each electrical device of the vehicle. It has a function to communicate. As shown in FIG. 6, when the inverter control units 12 </ b> A to 12 </ b> D of the motor drive devices 4 </ b> A to 4 </ b> D are integrated, communication cables, harnesses between the motor drive devices 4 </ b> A to 4 </ b> D and the host controller, Since the connector can be shared, the drive device can be made compact and low in cost.

  FIG. 7 shows an example in which the inverter control units 12A to 12D of the motor drive devices 4A to 4D are integrated, and the arithmetic unit 22 of each of the inverter control units 12A to 12D is shared by one unit. Shown in block diagram. Thus, by sharing the calculation unit 22 of each inverter control unit 12A to 12D with one unit, the state of the in-wheel motor units 3A to 3D and the motor driving devices 4A to 4D (the rotational speed, current value, temperature, etc.) ) Information can be easily shared without using communication.

Thus, when the calculation part 22 of each inverter control part 12A-12D is shared and integrated by one thing, the inverter control parts 12A-12D of several motor drive device 4A-4D drive the inverter part 13. The control method for driving the element 15 by the PWM method may be used, and the plurality of motor drive devices 4A to 4D may have the same PWM cycle, and the on / off timing of the drive element 15 may be shifted from each other.
For example, the center of the on-timing of the drive element 15 of the inverter unit 13 of each of the motor drive devices 4A to 4D may be shifted so that the PWM cycle is divided by the number of motor drive devices 4A to 4D at equal intervals. Instead of the center of the on-timing, the start of the on-timing may be shifted so that the PWM period is divided by the number of the motor driving devices 4A to 4D to be equally spaced.

Specifically, in the case of two-wheel drive, the motor drive devices 4A, 4B or 4C, 4D may shift the on / off timing of the drive element 15 of the inverter unit 13 by 180 degrees with respect to each other in the PWM cycle.
In the case of four-wheel drive, the motor drive devices 4A to 4D may shift the on / off timing of the drive element of the inverter unit 13 by 90 degrees with respect to each other in the PWM cycle.
In the case of 8-wheel drive, the motor drive devices 4A to 4D and the like may shift the on / off timing of the drive element 15 of the inverter unit 13 by 45 degrees with respect to each other in the PWM cycle.

FIG. 8 shows a voltage / current waveform when the motor is driven. The inverter control units 12, 12A to 12D shown in FIGS. 2, 3, 6, and 7 turn on and off the drive element 15 of the inverter unit 13 by PWM control to generate a sine wave current and the in-wheel motor units 3A to 3D. It flows through the coil of the stator 17a in the motor 17.
FIG. 9 shows the ON timing of the drive elements 15 of the motor drive device 4A and the motor drive device 4B. In FIG. 9A, the timing is determined so as to be equally spaced with reference to the center of each on-operation time of the motor driving device 4A and the motor driving device 4B. In FIG. 9B, the timing is determined so as to be equally spaced with reference to the start of each ON operation. By sharing the calculation unit 22 as shown in FIG. 7, the drive element ON timing of the plurality of motor drive devices 4 </ b> A to 4 </ b> D can be easily controlled, and thus the timing can be shifted in this way. Further, as shown in FIGS. 9A and 9B, the peak value of the ripple current from the shared smoothing capacitor C can be reduced by shifting the motor driving device 4A and the motor driving device 4B at equal intervals. Therefore, it is possible to reduce the size of the smoothing capacitor.

  FIG. 9C shows a case where, for example, in the case of four-wheel drive, four motor driving devices 4A to 4D are installed to independently drive the four in-wheel motor units 3A to 3D. In this example, one cycle of PWM control is divided into four, and control is performed so that the center of the on-operation time of each driving device comes at intervals of 90 degrees. For this reason, when the load is low, it is not necessary to instantaneously supply a large current from the battery, and the current is smoothed. The timing is not limited to four-wheel drive, but is determined by the number of drive motors.

  10 to 12 show another embodiment of the present invention. In-wheel motor drive may use a booster circuit to increase the power supply voltage of the battery in order to improve efficiency. In this embodiment, in the driving apparatus for an in-wheel motor vehicle in the previous embodiment shown in FIG. 1, four motors are provided in the same case 7 as in the arrangement configuration example of the components shown schematically in FIG. In addition to the driving devices 4A to 4D, a booster 25 is arranged. FIG. 11 shows a schematic diagram of a circuit configuration in which the booster 25 is added to the motor driving devices 4A to 4D. In this case, the smoothing circuit 11 of the motor drive device main body 10 is arranged on the output side of the booster 25. As shown in a schematic diagram of the circuit configuration in FIG. 14, the booster 25 includes a plurality (four in this case) of booster circuits connected in parallel, each including a plurality of drive elements 27, a reactor 28, and a rectifier 29, and And a boosting control unit 26 that controls on / off of each of the booster circuits, and raises the power supply voltage supplied from the battery unit. In FIG. 14, for simplification, the battery unit (battery 5 and battery controller unit 6) in FIG. The parts 3A to 3D are represented by a smoothing capacitor C and a load. Other configurations are the same as those of the previous embodiment shown in FIG.

  FIG. 12 is a front view showing an example of the arrangement configuration of the main body 10, the cooler 14, and the booster 25 of each motor driving device 4 </ b> A to 4 </ b> D in the case 7. In this arrangement configuration example, all of the main body portions 10 of the motor drive devices 4A to 4D are positioned close to the cooling surface of one cooler 14 in which those inverter portions 13 are shared by the motor drive devices 4A to 4D. As shown, the cooler 14 is disposed on one side, and the booster 25 is disposed on the cooling surface on one side of the cooler 14 opposite to the motor drive device main body.

  In addition, if the part to be cooled (mainly the inverter unit 13) of the main body 10 of each motor driving device 4A to 4D can be efficiently arranged on the cooling surface of the cooler 14, the main body of each motor driving device 4A to 4D. You may arrange | position some of 10 to the cooling surface of the one side in which the pressure | voltage rise part 25 of the cooler 14 is arrange | positioned.

  FIG. 13 is an example of the arrangement configuration of FIG. 12 in which all the main body portions 10 of the motor driving devices 4A to 4D are arranged on one side of one cooler 14, and the inverter control units 12A to 12D of the motor driving devices 4A to 4D. An example in which is integrated is shown in a front view. Also in this case, as shown in FIG. 7 in the previous embodiment, the calculation units 22 of the inverter control units 12A to 12D may be shared. Further, the boosting control unit 26 (FIG. 14) of the boosting unit 25 may be integrated with the control unit 10 of each motor driving device 4A to 4D. Furthermore, the second calculation unit 46 included in the boosting control unit 26 and the calculation unit 22 of the control unit 10 of each of the motor drive devices 4A to 4D may be shared by one calculation unit.

  The circuit configuration example of the booster 25 shown in FIG. 14 shows a case where four booster circuits are connected in parallel, but the booster circuit may be two or more circuits. As described above, the booster unit 25 is configured by a plurality of booster circuits connected in parallel and a single booster control unit 26 that performs on / off control of the plurality of drive elements 27 constituting each booster circuit. As shown in FIG. 15 (A), the on / off timing signals from the output units 26a to 26d corresponding to the drive elements 27 in the boost control unit 26 can be shifted from each other, whereby the motor drive devices 4A to 4D. The ripple current flowing to the smoothing capacitor C constituting the input-side smoothing circuit 11 can be reduced as shown in FIG. Since the ripple current can be reduced, the size of the smoothing capacitor C constituting the smoothing circuit 11 can be reduced. Moreover, the reactor 28 can be reduced in size by using a plurality of reactors 28. As a result, the drive device can be reduced in size and cost.

  For comparison with the booster 25 of this embodiment, a circuit configuration of a general booster is shown in FIG. In this conventional booster 45, each booster circuit is constituted by one drive element 37, a reactor 38, and a rectifier 39. In this circuit configuration, the current flowing through the drive element 37 and the current flowing through the rectifier 39 are switched depending on the on / off timing of the drive element 37, so that the current flowing through the capacitor constituting the smoothing circuit 41 on the input side of the motor drive device. Shows an intermittent current waveform as shown in FIG.

In this embodiment, as described above, the first calculation unit 22 of the inverter control unit 12 and the second calculation unit 46 of the boosting control unit 26 are integrated, and the boosting control of the boosting unit 25 is performed. The unit 26 drives the plurality of drive elements 27 by the PWM method, equalizes the PWM periods of the plurality of drive elements 27, and shifts the on / off timing of each drive element 27.
When the arithmetic units are integrated in this way, the ripple current to the smoothing circuit can be reduced even if the on / off timings of the plurality of drive elements of the booster unit are shifted.

When the on / off timings of the plurality of drive elements 27 of the boost unit 25 are shifted, the boost control unit 26 of the boost unit 25 determines that the center of the on / off timing of each drive element 27 is the PWM cycle. It is also possible to divide by 27 pieces and shift them to be equally spaced.
The start of the on / off timing may be shifted instead of the center of the on / off timing. That is, the boosting control unit 26 of the boosting unit 25 may shift the start of the on / off timing of each drive element 27 so that the PWM cycle is divided by the number of the drive elements 27 to be equally spaced. .

  When shifting the on / off timings of the plurality of driving elements 27 of the boosting unit 25, the boosting control unit 26 of the boosting unit 25 performs control so that all the on timings of the plurality of driving elements 27 do not overlap. Also good.

When the inverter control unit 12 and the boosting control unit 26 of the boosting unit 25 are integrated so that at least a part is shared among the plurality of motor driving devices 4A to 4D, respectively, the boosting unit The 25 boost control units 26 may drive the drive elements 27 by the PWM method so that the PWM cycle of the plurality of drive elements 27 is variable.
In this case, the boosting control unit 26 of the boosting unit 25 may drive all of the plurality of drive elements 27 with the same cycle.

Further, the boosting control unit 26 of the boosting unit 25 may fix the PWM on / off ratio and make the PWM cycle variable.
In this case, the boosting control unit 26 of the boosting unit 25 fixes the PWM ON ratio of the plurality of drive elements 27 so as to be an interval obtained by dividing the PWM cycle by the number of the plurality of drive elements 27, The on-timing of each drive element 27 may be shifted so as not to overlap.
Further, the boosting control unit 26 of the boosting unit 25 fixes the PWM off ratio of the plurality of drive elements 27 so as to be an interval obtained by dividing the PWM cycle by the number of the plurality of drive elements 27, and drives each drive. It may be shifted so that the on-timing of the element 27 does not overlap.

Further, the boosting unit 25 may have a plurality of driving elements 27 and a plurality of reactors 28 with respect to one boosting control unit 26. The booster 25 may be driven such that the operation start times and the operation stop times of the plurality of drive elements 27 are different from each other.
The booster 25 has a plurality of reactors 28, and by shifting the timing of current application to each reactor 28, the ripple current of the smoothing circuit can be reduced, and the capacitor of the smoothing circuit can be reduced in size. By using a plurality of reactors 28, the reactor 28 can be downsized. As a result, the driving device for the in-wheel motor vehicle can be further reduced in size, weight, and cost.

  The boosting unit 25 may make the intervals of the operation start times of the plurality of driving elements 27 constant. The booster 25 may be configured not to overlap the operation times of a plurality of drive elements. This also reduces the ripple current.

FIG. 16 shows a case where the ON time D1 of each drive element 27 is extended, and the supply current can be varied. Although not shown in the booster 25, the voltage applied to both ends of the load in FIG. 14 is monitored, and the output voltage is determined according to the load by varying the PWM on-time (duty).
Since the ripple current can be reduced by shifting the timing of the output currents of the plurality of drive elements 27, it is efficient to set the ON operation timings of the drive elements 27 at equal intervals.

In FIG. 17, the timing is determined so as to be equally spaced with reference to the center of each on-operation time. In FIG. 18, the timing is determined so as to be equally spaced with reference to the start of each on-operation time.

  Further, control is performed so that the plurality of drive elements 27 are not all turned on simultaneously. If all the drive elements 27 are turned on at the same time, the off times do not overlap, so the output current of the booster 25 becomes intermittent and the ripple current increases.

FIG. 19 shows the ON timing of the drive element 27 and the current waveform. FIG. 19 shows a case where one of the plurality of drive elements 27 is always on. In this case, since the circuit input current is continuous, pulsation of the current supplied from the battery can be reduced. Further, distortion of the output current as seen in FIGS. 15 and 16 is also reduced.
FIG. 20 shows a case where one of the drive elements 27 is always turned off so that the off timings of the drive elements 27 do not overlap and an intermittent current is not generated. In this case, as can be seen from the figure, the ripple of the output current is minimized.
Further, the output current can be controlled by fixing the timing at the on / off ratio of FIG. 19 or FIG. 20 where the ripple current is small and changing the PWM cycle.

FIG. 21 is a diagram in which the period of FIG. 20 is halved. Since the pulse width of one time is shortened, the output current decreases when the cycle is shortened. Conversely, if the cycle is lengthened, the output current increases.
Here, when the period is varied, the on / off ratio is not limited to that shown in FIG. It is also possible to combine variable period and variable on / off ratio. For example, if the cycle variable range is set to be higher than the audible band and the output is further increased from the upper limit of the cycle, the ratio of the on operation time is increased, or if the output is large at the minimum value of the cycle setting, It is an operation such as lowering the ratio.

  Further, the rectifier 29 (see FIG. 14) used in the booster circuit 25 turns on the drive element 27 from a state in which the drive element 27 is energized in the forward direction (from left to right in FIG. 14), When a reverse voltage is applied instantaneously, a reverse recovery current (from the right to the left of the rectifier) flows. Since this reverse recovery current is a noise generation source, in order to prevent it, it is sufficient that the rectifier is not energized in the forward direction at the timing when the drive element 27 is turned on. The rectifier current waveform in FIGS. 15 and 16 will be described. In FIG. 15, the reactor energy is consumed before the drive element 27 is turned on, and the rectifier 29 is not energized. In FIG. 16, the drive element 27 is turned on while the rectifier 29 is energized. The rectifier current instantaneously becomes zero at the timing when the drive element 27 is turned on. Although not shown here, in FIG. 16, an instantaneously reverse current flows when the drive element 27 is turned on. That is, the output voltage may be controlled by varying the cycle by controlling the on / off timing so that the forward energization ends at the timing when the drive element 27 is turned on.

  FIG. 22 shows another circuit configuration example of the booster 25. In this circuit configuration example, a current from a power source is supplied to the motor driving devices 4A to 4D in parallel to a plurality of booster circuits that are made up of a reactor 28 and a rectifier 29 and are connected in parallel to each other without passing through these reactors 28. The bypass path 30 is connected. This bypass path 30 consists of a rectifier.

  In the booster 25, the boosted voltage is determined according to the rotation speed of the in-wheel motor. That is, when the rotational speed is lower than a predetermined value, the boosting operation is not performed. As shown in FIG. 23, in the conventional circuit configuration of the booster, current is supplied from the power source via the reactor 38 even when the boosting operation is not performed. The reactor 38 has a resistance value of about several tens to several hundreds mΩ, and the loss due to this resistance cannot be ignored under a driving condition where the driving current is 100 A or more like an in-wheel motor. Therefore, when the bypass path 30 is provided as shown in FIG. 22, it is possible to reduce the loss during the low rotation operation.

  In each of the above embodiments, as shown in FIG. 23, the in-wheel motor vehicle 1 is a four-wheel drive electric vehicle or a fuel cell vehicle in which in-wheel motor units 3A to 3D are arranged on the front left and right wheels and the rear left and right wheels, respectively. A case (same as FIG. 1 and FIG. 8) is illustrated, and four motor driving devices 4A to 4D corresponding to the in-wheel motor units 3A to 3D are gathered and arranged in one place. However, in the same four-wheel drive electric vehicle or fuel cell vehicle, for example, as shown in FIG. The two motor driving devices 4C and 4D corresponding to the in-wheel motor units 3C and 3D of the rear left and right wheels may be collected and arranged in one place at the rear of the vehicle. In the present invention, the in-wheel motor vehicle 1 is a two-wheel drive vehicle as shown in FIG. 25, or a hybrid vehicle in which one of the front left and right wheels and the rear left and right wheels is driven by an internal combustion engine (FIG. 25). Here, an example in which the in-wheel motor units 3C and 3D are arranged on the rear left and right wheels) is also arranged and the two motor driving devices 4C and 4D corresponding to the two in-wheel motor units 3C and 3D are collected and arranged in one place. It can be applied.

DESCRIPTION OF SYMBOLS 1 ... In-wheel motor vehicle 2A-2D ... Wheel 3A-3D ... In-wheel motor part 4A-4D ... Motor drive device 7 ... Case 10 ... Main part 11 of motor drive device ... Smoothing circuit 12, 12A-12D ... Inverter control part DESCRIPTION OF SYMBOLS 13 ... Inverter part 14 ... Cooler 15 ... Drive element 22 ... Operation part 25 ... Boosting part 26 ... Boosting control part 27 ... Drive element 28 ... Reactor 29 ... Rectifier 30 ... Bypass path C ... Smoothing capacitor

Claims (17)

A plurality of drive motors respectively disposed on at least two drive wheels of a plurality of drive wheels of the vehicle, and a plurality of motor drive devices for controlling each of the drive motors, the motor drive device having a smoothing capacitor. And a smoothing circuit that smoothes the DC power supplied from the battery unit and a plurality of drive elements that perform a switching operation, and the DC power input through the smoothing circuit is converted into a three-phase alternating current by the intermittent connection of the drive elements. In a motor drive device for driving wheels of a vehicle having an inverter unit, an inverter control unit that controls the inverter unit, and a cooler that cools the inverter unit,
The plurality of motor drive devices are arranged in the same case, and the plurality of motor drive devices share the smoothing capacitor that is a component of these motor drive devices with each other, and the inverter control unit includes the inverter unit. A calculation unit having a function of determining an on / off timing of the drive element in the motor and controlling a torque or a rotation speed of the motor of the in-wheel motor unit, and the drive element in the inverter unit according to a command from the calculation unit A driving element pre-driver circuit for controlling on / off of the driving element, wherein the plurality of motor driving devices share the arithmetic unit of the inverter control unit, and the driving element pre-driver circuit is connected to each inverter. provided separately to the control unit, said inverter control unit of the plurality of motor drive, the drive of the inverter unit A control system for driving an element in a PWM system, wherein the plurality of motor driving devices have the same PWM period and the on / off timing of the driving element is shifted from each other. Motor drive device. Oite to claim 1, wherein the plurality of motor drive, so that the center of the on-timing of the driving element of the inverter section of each motor driving device, at equal intervals by dividing the PWM cycle by the number of motor driving device A motor drive device for a drive wheel of a vehicle to be shifted. Oite to claim 1, wherein the plurality of motor drive, the start of the driving element on the timing of the inverter section of each motor driving device is shifted such that at regular intervals by dividing the PWM cycle by the number of motor driving device Vehicle drive device In any one of claims 1 to 3, wherein the motor drive apparatus, the on-off timing of the driving element of the inverter unit, a motor drive for driving wheels of the vehicle shifted 90 degrees PWM cycle from each other. In any one of claims 1 to 4, wherein each motor driving device has a booster for boosting the supply voltage from the power source, these booster is, the step-up control unit, the drive element, a reactor, The plurality of motor drive devices are integrated with the inverter control unit and the boost control unit of the boost unit so that at least a part is shared between the plurality of motor drive devices. Motor drive device for a drive wheel of a vehicle. 6. The first calculation unit according to claim 5 , wherein the inverter control unit has a function of determining an on / off timing of the driving element in the inverter unit and controlling a torque or a rotation speed of a motor of the in-wheel motor unit. The plurality of inverter control units share the first calculation unit, and the boosting control unit includes a second calculation unit, the first calculation unit of the inverter control unit, and the boosting unit A motor drive device for a drive wheel of a vehicle in which the inverter control unit and the boost control unit are integrated with each other by sharing the second calculation unit of the control unit. 7. The motor driving device for driving wheels of a vehicle according to claim 6 , wherein the boosting unit has a plurality of driving elements and a plurality of reactors with respect to one boosting control unit. 8. The vehicle according to claim 7 , wherein the boosting control unit of the boosting unit drives a plurality of drive elements by a PWM method, equalizes the PWM periods of the plurality of drive elements, and shifts the on / off timing of each drive element. Motor drive device for drive wheels. 9. The boost control unit of the boost unit according to claim 8 , wherein the center of the on / off timing of each drive element is shifted so that the PWM period is divided by the number of drive elements to be equally spaced. Motor drive device. 9. The boost control unit of the boost unit according to claim 8 , wherein the start of on / off timing of each drive element is shifted so that the PWM cycle is divided by the number of drive elements to be equally spaced. Motor drive device. In any one of claims 7 to 10, the boost control section of the step-up unit, a plurality of motor drive for driving wheels of the vehicle in which all on-timing is controlled so as not to overlap the drive element. In any one of claims 7 to 10, the boost control section of the step-up unit, a motor drive for driving wheels of the vehicle where the PWM period of the plurality of driving elements is variable. 13. The motor driving device for driving wheels of a vehicle according to claim 12 , wherein the boosting control unit of the boosting unit drives all of the plurality of driving elements at the same cycle. According to claim 12 or claim 13, the step-up control unit of the booster is in the fixed percentage of the PWM on and off, the motor drive for driving wheels of the vehicle in which the period of the PWM variable. 15. The boosting control unit of the boosting unit according to claim 14 , wherein the PWM on ratio of the plurality of driving elements is fixed so as to be an interval obtained by dividing the PWM period by the number of the plurality of driving elements. The motor drive device for the drive wheel of the vehicle which shifts so that the on-timing of the vehicle does not overlap. 15. The boosting control unit of the boosting unit according to claim 14 , wherein the PWM off ratio of the plurality of drive elements is fixed such that the PWM period is an interval obtained by dividing the PWM cycle by the number of the plurality of drive elements. The motor drive device for the drive wheel of the vehicle which shifts so that the on-timing of the vehicle does not overlap. In any one of claims 6 through claim 16, a motor drive for driving wheels of a vehicle having a bypass path for supplying current without passing through the reactor.

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