JP2019187208A - Power conversion device with anti-vibration mount - Google Patents

Abstract

To provide a power conversion device including an anti-vibration mount using a magnetorheological fluid, and does not require a dedicated coil for adjusting the viscosity of the magnetorheological fluid.SOLUTION: A power conversion device 10 disclosed in this specification includes a plurality of power conversion circuits and an anti-vibration mount 30. Each of the plurality of power conversion circuits includes a reactor. The anti-vibration mount 30 seals the magnetorheological fluid or the electrorheological fluid. The anti-vibration mount 30 is arranged such that the magnetic field generated by the reactor 20 included in one of the plurality of voltage conversion circuits passes through the magnetorheological fluid or the electrorheological fluid. A reactor of the voltage conversion circuit also serves as viscosity adjusting means, and there is no need to provide a coil exclusively for viscosity adjustment.SELECTED DRAWING: Figure 2

Description

  The technology disclosed in this specification relates to a power conversion device. In particular, the present invention relates to a power conversion device having a vibration-proof mount on a housing.

  Patent Document 1 discloses a vibration damping device capable of adjusting a damping characteristic. The vibration damping device includes a vibration-proof mount and a coil sealed with a magnetorheological fluid. A magnetorheological fluid is a fluid whose viscosity changes according to the strength of the magnetic field received. The vibration damping device of Patent Document 1 can adjust the attenuation characteristic by adjusting the strength of the magnetic field applied to the magnetorheological fluid by the coil.

JP 2000-274478 A

  The technology disclosed in the present specification provides a power conversion device with an anti-vibration mount that utilizes a reactor included in a voltage conversion circuit for viscosity adjustment of a magnetic viscous fluid (or electrorheological fluid) of the anti-vibration mount. By using a reactor, a coil for viscosity adjustment is not required.

  The power conversion device disclosed in the present specification includes a plurality of voltage conversion circuits connected in parallel and a vibration-proof mount that seals a magnetorheological fluid or an electrorheological fluid. And the vibration-proof mount is arrange | positioned so that the magnetic field which the reactor contained in one of several voltage conversion circuits generate | occur | produces may pass a magnetorheological fluid or an electrorheological fluid. That is, the damping characteristic of the magnetorheological fluid (anti-vibration mount) is adjusted by the magnetic field generated by the reactor. The electrorheological fluid is a fluid whose viscosity changes according to the strength of the electric field applied. Since the reactor generates an electric field as well as a magnetic field, the same effect can be obtained by using an electrorheological fluid instead of the magnetorheological fluid. The magnetorheological fluid is also called a magnetic fluid.

  In addition, in the power conversion device disclosed in this specification, a plurality of voltage conversion circuits including a reactor are connected in parallel. By connecting a plurality of voltage conversion circuits in parallel, the allowable current of the power conversion device can be increased. The power conversion device disclosed in the present specification can realize both increase in allowable current and attenuation adjustment of the vibration isolation mount at the same time.

  Details and further improvements of the technology disclosed in this specification will be described in the following “DETAILED DESCRIPTION”.

It is a block diagram of the electric vehicle including the power converter device of an Example. It is sectional drawing of the housing | casing of a power converter device. It is sectional drawing along the III-III line of FIG.

  A power converter according to an embodiment will be described with reference to the drawings. The power converter of the embodiment is mounted on an electric vehicle. In FIG. 1, the block diagram of the drive system of the electric vehicle 100 containing the power converter device 10 of an Example is shown. The electric vehicle 100 can be driven by the motor 52. The power conversion device 10 is a device that converts the DC power of the battery 50 into AC suitable for driving the motor 52. The power conversion device 10 can also charge the battery 50 by converting AC power (regenerative power) generated when the motor 52 is reversely driven by the inertial force of the vehicle into DC power.

  The DC terminal of the power converter 10 is connected to the battery 50 via the system main relay 51. The AC terminal of the power converter 10 is connected to the motor 52.

  The power conversion device 10 includes two voltage conversion circuits 11 a and 11 b, an inverter circuit 12, two capacitors 8 and 9, and a controller 13. The two voltage conversion circuits 11a and 11b are connected in parallel. The voltage conversion circuits 11a and 11b include common low voltage ends 14a and 14b and common high voltage ends 15a and 15b. A capacitor 8 is connected between the low voltage terminals 14a and 14b, and a capacitor 9 is connected between the high voltage terminals 15a and 15b.

  The voltage conversion circuit 11a will be described. The voltage conversion circuit 11a includes two switching elements 4a and 5a, two diodes 6a and 7a, and a reactor 3. The two switching elements 4a and 5a are connected in series. The series connection of the two switching elements 4a and 5a is connected between the high voltage ends 15a and 15b. A diode 6a is connected in antiparallel to the switching element 4a, and a diode 7a is connected in antiparallel to the switching element 5a. One end of the reactor 3 is connected to the midpoint of the series connection of the two switching elements 4a and 5a. The other end of the reactor 3 is connected to the positive electrode 14a at the low voltage end. The negative electrode 14b at the low voltage end and the negative electrode 15b at the high voltage end are directly connected.

  The voltage conversion circuit 11a boosts the voltage applied to the low voltage terminals 14a and 14b and outputs the boosted voltage from the high voltage terminals 15a and 15b, and lowers the voltage applied to the high voltage terminals 15a and 15b. Both step-down operations output from the voltage terminals 14a and 14b can be performed. That is, the voltage conversion circuit 11a is a bidirectional DC-DC converter. The voltage applied to the low voltage terminals 14a and 14b is an output voltage of the battery 50, and the voltage applied to the high voltage terminals 15a and 15b is a voltage of regenerative power.

  The switching element 5a and the diode 6a are mainly involved in the step-up operation, and the switching element 4a and the diode 7a are mainly involved in the step-down operation. The switching elements 4a and 5a are driven by the controller 13. The controller 13 determines the voltage ratio between the low voltage terminals 14a and 14b and the high voltage terminals 15a and 15b, and determines the duty ratio of the switching elements 4a and 5a so that the voltage ratio is realized. The controller 13 provides a complementary PWM signal to the switching elements 4a and 5a. The complementary PWM signal means a signal obtained by reversing the HIGH level and LOW level of the PWM signal applied to the switching element 4a. By providing a complementary PWM signal to the switching elements 4a and 5a, the voltage conversion circuit 11a can respond to the balance between the voltage applied to the low voltage terminals 14a and 14b and the voltage applied to the high voltage terminals 15a and 15b. The step-down operation is switched passively to the step-up operation. In the electric vehicle 100, power running (a state in which the motor 52 outputs torque) and regeneration (a state in which the motor 52 generates regenerative power) are frequently switched according to the driver's accelerator operation and brake operation. In the voltage conversion circuit 11a to which a complementary PWM signal is applied, the step-up and step-down are passively switched according to power running and regeneration.

  The voltage conversion circuit 11b also has the same configuration as the voltage conversion circuit 11a. That is, the voltage conversion circuit 11b includes two switching elements 4b and 5b, two diodes 6b and 7b, and a reactor 20. The two switching elements 4b and 5b are connected in series, and the series connection of the switching elements is connected between the high voltage ends 15a and 15b. A diode 6b is connected in antiparallel to the switching element 4b, and a diode 7b is connected in antiparallel to the switching element 5b. One end of the reactor 20 is connected to the midpoint of the series connection of the two switching elements 4b and 5b, and the other end of the reactor 20 is connected to the positive electrode 14a at the low voltage end.

  The voltage conversion circuit 11b is also a bidirectional DC-DC converter like the voltage conversion circuit 11a. The switching elements 4b and 5b of the voltage conversion circuit 11b are also controlled by the controller 13.

  The inverter circuit 12 is connected to the common high voltage terminals 15a and 15b of the voltage conversion circuits 11a and 11b. The inverter circuit 12 converts DC power output from the voltage conversion circuits 11 a and 11 b into AC and supplies the AC to the motor 52. The inverter circuit 12 may convert the AC regenerative power generated by the motor 52 into DC power and supply it to the voltage conversion circuits 11a and 11b. Since the inverter circuit 12 is well known, a detailed description of the circuit is omitted. Capacitor 8 temporarily stores electrical energy together with reactors 3 and 20. Capacitor 8 relaxes a current change at the time of switching of switching elements 4a, 4b, 5a, and 5b in the step-down operation or step-up operation. The capacitor 9 suppresses pulsation of current flowing between the voltage conversion circuits 11a and 11b and the inverter circuit 12.

  The reactor 20 of the voltage conversion circuit 11b is incorporated in an anti-vibration mount 30 described later. In FIG. 1, the anti-vibration mount 30 is schematically represented by a broken-line rectangle. Next, the anti-vibration mount 30 will be described with reference to FIGS. 2 shows a cross-sectional view of the casing 40 of the power conversion device 10, and FIG. 3 shows a cross-section along the line III-III in FIG. In FIG. 2, illustration of a part of the housing 40 is omitted. In FIG. 2, illustration of various electrical components (electrical components illustrated in FIG. 1) housed in the housing 40 is also omitted. However, only the reactor 20 is schematically drawn.

  The anti-vibration mount 30 is a component that supports the housing 40 of the power conversion device 10, and is disposed between the housing 40 and the vehicle body 39 of the electric vehicle 100. A recess 41 is provided in the lower portion of the housing 40, and the vibration isolation mount 30 is disposed inside the recess 41. That is, the power conversion device 10 according to the embodiment is a power conversion device with an anti-vibration mount in which the housing 40 is provided with the anti-vibration mount 30.

  The anti-vibration mount 30 includes a base plate 35, a cylinder 31, a piston 32, and a spring 36. The base plate 35 is fixed to the vehicle body 39 with bolts 37. The vehicle body 39 is, for example, a transaxle case that houses the motor 52.

  A cylinder 31 is fixed on the base plate 35. A piston 32 is accommodated inside the cylinder 31 so as to be movable up and down. Magnetorheological fluid MR is sealed in the internal spaces 34 a and 34 b of the cylinder 31. In FIG. 2, the magnetorheological fluid MR is represented by gray hatching.

  The piston 32 is provided with a plurality of through holes 33 penetrating the piston 32 up and down. When the piston 32 moves up and down, the magnetorheological fluid MR moves between the space above the piston 32 (upper space 34 a) and the space below the piston 32 (lower space 34 b) through the through hole 33. The vibration of the piston 32 is attenuated by the movement of the magnetorheological fluid MR.

  A hole is provided in the upper part of the cylinder 31, and a column 42 extending from the lower part of the casing 40 (the center of the bottom of the recess 41) passes through the hole and is connected to the upper part of the piston 32. The piston 32 and the housing 40 are connected, and the housing 40 also moves up and down in accordance with the vertical movement of the piston 32. A flange 44 is provided around the housing 40, and a spring 36 is sandwiched between the lower flange surface of the flange 44 and the base plate 35. The spring 36 urges the housing 40 upward. The strength of the spring 36 is adjusted so that the urging force of the spring 36 is balanced with the weight of the housing 40 when the piston 32 is positioned at the approximate center of the cylinder 31 in the vertical direction.

  When the vehicle body 39 vibrates, the piston 32 moves up and down together with the housing 40. As the piston 32 moves up and down, the magnetorheological fluid MR passes through the through hole 33 of the piston 32 and moves between the upper space 34a and the lower space 34b. The magnetorheological fluid MR absorbs the vibration energy of the piston 32, and the housing 40 is damped.

  A reactor 20 is embedded in the piston 32. The piston 32 is made of resin and seals the reactor 20. In FIG. 2, the continuity line 43 that passes through the support column 42 from the inside of the housing 40 and reaches the reactor 20 is schematically shown by a virtual line.

  FIG. 3 is a cross-sectional view of the piston 32 cut along a horizontal plane. As shown in FIG. 3, the reactor 20 includes a ring-shaped core 21 and a coil 22 wound around the core 21. The resin of the piston 32 seals the reactor 20 composed of the core 21 and the coil 22. The through hole 33 passes through the core 21.

  When the coil 22 of the reactor 20 is energized, a magnetic field is generated. The magnetic field mainly passes through the core 21. As described above, the magnetorheological fluid MR passes through the through hole 33 provided in the core 21. The magnetic field generated by the coil 22 also passes through the magnetorheological fluid MR. In other words, the anti-vibration mount 30 is configured such that the magnetic field generated by the reactor 20 passes through the magnetorheological fluid MR.

  When the magnetorheological fluid sealed in the cylinder 31 is subjected to a magnetic field, its viscosity characteristics change. The viscosity characteristic of the magnetorheological fluid sealed in the cylinder 31 determines the damping characteristic of the vibration isolating mount 30. In the power conversion device 10, the controller 13 determines the current flowing through the reactor 20 so that the anti-vibration mount 30 has preferable attenuation characteristics. Specifically, the controller 13 determines the current flowing through the reactor 20 so as to have an attenuation characteristic that suppresses the vibration peak at the resonance frequency of the housing 40. The controller 13 is configured so that each voltage conversion circuit 11a is appropriately distributed to the two voltage conversion circuits 11a and 11b so that the amount of current that should flow through the two voltage conversion circuits 11a and 11b connected in parallel is appropriately distributed. , 11b are driven. At this time, the controller 13 determines the amount of current that should flow through the reactor 20 (that is, the amount of current that should flow through the voltage conversion circuit 11b) so that the anti-vibration mount 30 has desirable damping characteristics. Each switching element is driven so that the remaining amount of current flows through the voltage conversion circuit 11a.

  The vibration characteristic (frequency characteristic) of the housing 40 varies depending on the vehicle speed. Therefore, the controller 13 adjusts the current flowing through the reactor 20 so that the anti-vibration mount 30 has a preferable damping characteristic corresponding to the vehicle speed.

  The magnetorheological fluid MR is a magnetic colloid liquid whose main component is a base liquid containing ferromagnetic fine particles whose surfaces are covered with a surfactant. For example, magnetite or manganese zinc ferrite is used for the ferromagnetic particles. Oil (lubricating oil) is used as the base liquid.

  The power conversion device 10 can adjust the attenuation characteristics of the anti-vibration mount 30 using the reactor 20. There is no need to provide a dedicated coil for applying a magnetic field to the magnetorheological fluid of the vibration isolation mount 30. Furthermore, since the power converter 10 has the two voltage conversion circuits 11a and 11b connected in parallel, it also has an advantage that the allowable current is large.

  Points to be noted regarding the technology described in the embodiments will be described. Instead of the magnetorheological fluid, an electrorheological fluid whose viscosity changes according to the strength of the applied electric field may be used. In the vibration isolating mount 30, a through hole 33 through which the magnetorheological fluid MR passes is provided in the core 21 of the reactor 20 embedded in the piston 32. The through-hole 33 may be provided so as not to penetrate the core 21 and pass through the side of the core 21.

  The power conversion apparatus 10 according to the embodiment includes two voltage conversion circuits, and the reactor of one of the voltage conversion circuits also serves as an attenuation adjustment unit of the vibration isolation mount. The technology disclosed in this specification may be applied to a power conversion device in which three or more voltage conversion circuits are connected in parallel. The technology disclosed in the present specification may include two or more anti-vibration mounts. In the technology disclosed in this specification, N voltage conversion circuits are connected in parallel, and the reactors of at most N-1 voltage conversion circuits may serve as attenuation adjustment means of the vibration isolation mount. . Here, N> 1.

  In the power conversion device 10 of the embodiment, the reactor 20 is embedded in the piston 32 of the vibration isolation mount 30. The reactor 20 should just be arrange | positioned so that the magnetic field which generate | occur | produces may penetrate the magnetic viscous fluid of the vibration-proof mount 30. FIG. The reactor 20 may be disposed outside the vibration-proof mount 30. The power conversion device 10 according to the embodiment corresponds to an example of a power conversion device with an anti-vibration mount.

  Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above. The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology exemplified in this specification or the drawings can achieve a plurality of objects at the same time, and has technical usefulness by achieving one of the objects.

3: Reactors 4a, 4b, 5a, 5b: Switching elements 6a, 6b, 7a, 7b: Diode 8, 9: Capacitor 10: Power conversion device 11a, 11b: Voltage conversion circuit 12: Inverter circuit 13: Controller 20: Reactor 21 : Core 22: Coil 30: Anti-vibration mount 31: Cylinder 32: Piston 33: Through hole 35: Base plate 36: Spring 37: Bolt 39: Car body 40: Housing 41: Recess 42: Strut 44: Flange 50: Battery 52 : Motor 100: Electric vehicle

Claims (1)

A plurality of voltage conversion circuits connected in parallel, each including a reactor;
Anti-vibration mount sealed with magnetorheological fluid or electrorheological fluid;
With
The anti-vibration mount, wherein the anti-vibration mount is arranged so that a magnetic field generated by a reactor included in one of the plurality of voltage conversion circuits passes through the magnetorheological fluid or the electrorheological fluid Attached power converter.

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