JP6626382B2 - Power supply - Google Patents

Description

  The present invention relates to a power supply device including a relay between a secondary battery and a transformer circuit.

  2. Description of the Related Art Conventionally, electric vehicles, hybrid vehicles, and the like having an electric motor as a power source of a vehicle are known. These vehicles are equipped with a power supply device for supplying AC power to the electric motor. This power supply device includes, for example, a battery (secondary battery), a DC-DC converter (transformer circuit) that boosts the voltage of the battery, an inverter that converts the boosted DC power to AC power, a battery and the DC-DC A relay for switching between a connected state and a disconnected state with the converter.

JP-A-7-169380

  By the way, it is known that an abnormal noise is generated when the above-mentioned relay is switched on (connected state) / off (disconnected state). However, an abnormal noise is also generated while the relay is on (connected state). In particular, the switching of the relay on / off is limited to the time when the ignition switch is turned on / off, but the relay is kept turned on while the ignition switch is turned on. Therefore, the driver of the vehicle may feel discomfort due to the abnormal noise generated while the relay is on.

  As a countermeasure against the sound of the relay, there is a method of providing a sound absorbing material (for example, cotton) around the relay. For example, Patent Literature 1 discloses a method of filling the entire area between a relay cover and an outer cover with an insulating material in order to improve the soundproofing of the relay.

  However, if a member such as a sound absorbing material is separately provided as a measure against the sound of the relay, the cost and weight increase. By the way, if a member for noise suppression is provided so as to cover the relay, the relay is likely to break down due to heat or the like. Therefore, if the noise control members are provided in the entire surrounding area at some distance from the relay, a large amount of noise control members are required, and the cost and weight increase according to the amount.

  The present invention has been made in order to solve the above problems, and a power supply device capable of suppressing abnormal noise caused by a relay in a connected state without separately providing a member for sound suppression. The purpose is to provide.

  A power supply device according to the present invention includes a secondary battery, a transformer circuit, a first relay for switching a positive side of the secondary battery and the transformer circuit between a connected state and a cutoff state, and a negative electrode of the secondary battery and the transformer circuit. And a second relay for switching the side between a connected state and a disconnected state. The first relay and the second relay are configured such that a movable contact moves according to energization / non-energization of a coil. The movable contact comes into contact with the fixed contact when in the connected state, and the movable contact is separated from the fixed contact when in the cut-off state. The first relay and the second relay are connected to each other by a ripple current generated in the transformer circuit. It is characterized by being arranged at intervals of an odd multiple of a half wavelength of a vibration sound generated when flowing.

  The inventor of the present application has diligently studied the above-described problems, and as a result, when in the connected state, the movable contact in contact with the fixed contact vibrates due to the ripple current generated in the voltage transformer circuit, so that the vibration noise (different from the relay) is caused. Sound) is generated.

  Therefore, in the power supply device according to the present invention, the first relay on the positive electrode side and the second relay on the negative electrode side are arranged at an interval of an odd multiple of a half wavelength of the vibration sound generated by the ripple current. The sound wave of the vibration sound generated by the first relay and the sound wave of the vibration sound generated by the second relay have opposite phases. Thereby, the vibration sound generated by the first relay and the vibration sound generated by the second relay cancel each other, and the magnitude of the vibration sound is reduced. As described above, according to the power supply device of the present invention, it is possible to suppress the vibration sound (abnormal noise) generated in the relay due to the ripple current in the connected state without separately providing a sound countermeasure member. Become.

  In the power supply device according to the present invention, it is preferable that the half wavelength of the vibration sound is calculated using the switching frequency and the sound speed of the switching element of the transformer circuit. By doing so, a half wavelength of the vibration sound can be accurately obtained.

  In the power supply device according to the present invention, the first relay and the second relay are arranged such that a contact surface between the movable contact and the fixed contact of the first relay and a contact surface between the movable contact and the fixed contact of the second relay face each other. It is preferred to be arranged in. With this configuration, the vibration sound generated at the first relay is easily transmitted to the direction of the contact surface of the second relay, and the vibration sound generated at the second relay is easily transmitted to the direction of the contact surface of the first relay. Thus, the effect of suppressing vibration noise can be enhanced.

  In the power supply device according to the present invention, the first relay and the second relay are arranged such that an interval between the contact surface of the first relay and the contact surface of the second relay is an odd multiple of a half wavelength of the vibration sound. Is preferred. By doing so, the sound wave of the vibration sound generated by the first relay and the sound wave of the vibration sound generated by the second relay have exactly the opposite phases, and the effect of suppressing the vibration sound can be enhanced.

  The power supply device according to the present invention may be mounted on a vehicle provided with an electric motor as a power source, and the transformer circuit may increase the voltage of the secondary battery when the secondary battery is discharged. In the case of this configuration, the current flowing through the movable contact of the relay is large (particularly, the current (maximum value) that flows when the secondary battery is discharged to drive the electric motor is larger than when the secondary battery is charged), so that the ripple current is also large. . ADVANTAGE OF THE INVENTION According to the power supply device which concerns on this invention, even when a large electric current flows into a movable contact at the time of discharge of a secondary battery, etc., the vibration noise which generate | occur | produces in a relay by a ripple current can be suppressed.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to suppress the abnormal noise resulting from a relay at the time of a connection state, without providing a member for sound measures separately.

FIG. 2 is a block diagram illustrating a configuration of a power supply device according to the embodiment. It is a sectional view showing an example of a relay (OFF state) of a power supply device concerning an embodiment. It is a sectional view showing an example of the relay (ON state) of the power supply device concerning an embodiment. It is a figure showing arrangement of the 1st relay and the 2nd relay in the power supply device concerning an embodiment.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts have the same reference characters allotted. In each of the drawings, the same elements are denoted by the same reference numerals, and redundant description will be omitted.

  A power supply device 1 according to the embodiment will be described with reference to FIG. FIG. 1 is a block diagram illustrating a configuration of a power supply device 1 according to the embodiment. In the present embodiment, the present invention is applied to a power supply device 1 mounted on a vehicle having an electric motor as a drive source. The vehicle may be an electric vehicle (EV [Electric Vehicle]) including only an electric motor as a drive source, or a hybrid vehicle (HEV [Hybrid Electric Vehicle]) including an electric motor and an engine as a drive source.

  The power supply device 1 converts the DC power of the battery 10 into AC power and supplies it to the electric motor 2 when the vehicle is accelerating. Further, when the vehicle is decelerated, the power supply device 1 converts AC power generated by the electric motor 2 by regenerative braking into DC power to charge the battery 10. The electric motor 2 functions as an electric motor, and is, for example, a three-phase AC type AC synchronous motor. The electric motor 2 is a motor generator that also functions as a generator.

  The power supply device 1 includes a battery 10 (corresponding to a secondary battery described in the claims), a DC-DC converter 11 (corresponding to a transformer circuit described in the claims), an inverter 12, and a first relay. 13 and a second relay 14. The power supply device 1 is controlled by an ECU [Electronic Control Unit] 15.

  The battery 10 is a chargeable / dischargeable secondary battery, and includes, for example, a lithium ion battery and a nickel hydrogen battery. The battery 10 is a high-voltage battery, for example, a battery of several hundred volts. The battery 10 is configured to have a predetermined voltage by connecting a plurality of secondary batteries in series, for example, and the plurality of serially connected secondary batteries are stored in a battery box. The battery 10 is discharged when the electric motor 2 is energized, and charged when the electric motor 2 is regenerated.

  The DC-DC converter 11 boosts the DC voltage of the battery 10 to a desired voltage. Further, the DC-DC converter 11 reduces the high-voltage DC current converted by the inverter 12 to a voltage at which the battery 10 can be charged. The DC-DC converter 11 includes, for example, a reactor (power inductor), a switching element (for example, an IGBT), and the like, and accumulates and discharges electric energy in the reactor in accordance with ON / OFF of the switching element, so that the voltage is increased. change.

  In the DC-DC converter 11, a ripple current is generated with switching by the switching element. The frequency of the ripple current is the same as the switching frequency of the switching element. The switching frequency is, for example, several kHz to several tens kHz.

  The inverter 12 converts the high-voltage DC current boosted by the DC-DC converter 11 into a three-phase AC current, and supplies the AC current to the electric motor 2. The inverter 12 converts the three-phase alternating current generated by the electric motor 2 into a direct current. The inverter 12 includes, for example, two switching elements and two diodes corresponding to each phase of the electric motor 2, and the switching elements of each phase are turned on / off. The inverter 12 and the DC-DC converter 11 constitute, for example, a power control unit (PCU).

  The first relay 13 is a relay on the positive electrode side, and is provided on an energizing line 16 on the positive electrode side for connecting the battery 10 and the DC-DC converter 11. The second relay 14 is a negative-side relay, and is provided on the negative-side power supply line 17 for connecting the battery 10 and the DC-DC converter 11. The first relay 13 and the second relay 14 are stored in, for example, the battery box described above, and are attached to the same side surface of the battery box.

  Relays 13 and 14 switch battery 10 and DC-DC converter 11 between a connected state and a disconnected state. In the connected state, battery 10 and DC-DC converter 11 are electrically connected via relays 13 and 14. In the cutoff state, the battery 10 and the DC-DC converter 11 are cut off electrically. The relays 13 and 14 are switched to a connected state when a predetermined condition at the time of ON is satisfied after an ignition switch (not shown) is turned ON, and cut off when a predetermined condition at the time of OFF is satisfied after the ignition switch is turned OFF. State.

  The relays 13 and 14 are electromagnetic relays. An example of the configuration of the electromagnetic relays 13 and 14 will be described with reference to FIGS. FIG. 2 is a cross-sectional view illustrating an example of the relays 13 and 14 (OFF state) of the power supply device 1 according to the embodiment. FIG. 3 is a cross-sectional view illustrating an example of the relays 13 and 14 (ON state) of the power supply device 1 according to the embodiment. The first relay 13 and the second relay 14 have the same configuration. 2 and 3 are cross-sectional views taken along a line connecting the center of the fixed contact 21 and the center of the fixed contact 22.

  The relays 13 and 14 include a coil 20, a pair of fixed contacts 21 and 22, a movable contact 23, a fixed iron core 24, a movable iron core 25, a return spring 26, a rod 27, a contact pressure spring 28, And permanent magnets 29, 29.

  One fixed contact 21 of the first relay 13 is connected to one end of an energizing line 16a. The other end of the power supply line 16a is connected to a positive terminal (plus terminal) of the battery 10. One end of an energizing line 16b is connected to the other fixed contact 22 of the first relay 13. The other end of the energizing line 16b is connected to the DC-DC converter 11. The energizing line 16 includes the energizing line 16a and the energizing line 16b.

  One end of an energizing line 17b is connected to one fixed contact 21 of the second relay 14. The other end of the energizing line 17b is connected to the DC-DC converter 11. One end of an energizing line 17a is connected to the other fixed contact 22 of the second relay 14. The other end of the power supply line 17a is connected to a negative terminal (negative terminal) of the battery 10. The energizing line 17 includes the energizing line 17a and the energizing line 17b.

  The fixed contact 21 and the fixed contact 22 are arranged in parallel at a predetermined interval. One end face of the fixed contacts 21 and 22 on the movable contact 23 side is a flat end face, for example, a circular flat end face. One end face of the fixed contact 21 and one end face of the fixed contact 22 are arranged at the same height position.

  The movable contact 23 is arranged on one end face side of the fixed contacts 21 and 22 so as to face the one end face. The movable contact 23 is movable from a position that is a predetermined distance away from the fixed contacts 21 and 22 to a position that contacts each end face of the fixed contacts 21 and 22. The movable contact 23 has, for example, a flat plate shape.

  The fixed core 24 and the movable core 25 are arranged at the center of the cylindrical coil 20. The movable iron core 25 is arranged on one end face side of the fixed iron core 24 so as to face this one end face. The return spring 26 is arranged between the fixed iron core 24 and the movable iron core 25. One end of the rod 27 is fixed to the center of the movable iron core 25. The other end of the rod 27 passes through the center of the fixed iron core 24. The contact pressure spring 28 is arranged between the flange-shaped other end of the rod 27 and the movable contact 23.

  The pair of permanent magnets 29, 29 are permanent magnets for extinguishing arc discharge. The pair of permanent magnets 29, 29 are opposed to each other with the fixed contacts 21, 22 and the movable contact 23 interposed therebetween (particularly, the contact points between the fixed contacts 21, 22 and the movable contact 23). In particular, the N pole of one permanent magnet 29 and the S pole of the other permanent magnet 29 face each other. The permanent magnets 29, 29 have, for example, a flat plate shape.

  When the coil 20 is energized and excited, a magnetic flux is generated and a magnetic field is generated. The magnetic field magnetizes the fixed core 24 and the movable core 25 and attracts each other. Thereby, the movable iron core 25 moves to the fixed iron core 24 side, and the rod 27 moves with the movement of the movable iron core 25. With the movement of the rod 27, the movable contact 23 moves toward the fixed contacts 21 and 22, and the movable contact 23 contacts one end face of the fixed contact 21 and one end face of the fixed contact 22 as shown in FIG. I do. As a result, the relays 13 and 14 are connected (on), and the fixed contact 21 and the fixed contact 22 are electrically connected via the movable contact 23.

  When the current supply to the coil 20 is stopped, the coil 20 is demagnetized. Due to this demagnetization, the magnetization of the fixed iron core 24 and the movable iron core 25 is eliminated. As a result, the movable iron core 25 moves to the opposite side (the side away from the fixed iron core 24) to the fixed iron core 24 by the return spring 26, and the rod 27 moves with the movement of the movable iron core 25. With the movement of the rod 27, the movable contact 23 moves to a side opposite to the fixed contacts 21 and 22 (a side away from the fixed contacts 21 and 22), and as shown in FIG. Move away from As a result, the relays 13 and 14 are turned off (off).

  The ECU 15 that controls the relays 13 and 14 will be described. The ECU 15 includes a microprocessor for performing calculations, a ROM for storing programs for causing the microprocessor to execute various processes, a RAM for storing various data such as calculation results, a backup RAM for storing the stored contents, and an input / output device. It has an I / F and the like. The ECU 15 performs energization / de-energization of the relays 13 and 14 (coil 20), switching control of the switching element of the DC-DC converter 11, and switching control of the switching element of the inverter 12. Note that the ECU 15 may be, for example, a motor control ECU, a hybrid control ECU, or a plurality of ECUs. In the case of a configuration including a plurality of ECUs, for example, the energization / de-energization of the relays 13 and 14 is performed by the battery ECU, and the switching control of the DC-DC converter 11 and the inverter 12 is performed by the motor control ECU.

  A magnetic flux is generated between the N pole of one permanent magnet 29 and the S pole of the other permanent magnet 29 between the pair of permanent magnets 29, 29 to generate a magnetic field. When a current flows through the movable contact 23 in this magnetic field, an electromagnetic force is generated. Therefore, in the relays 13 and 14, an electromagnetic force acts on the movable contact 23 in the connected state. The direction in which the electromagnetic force acts depends on the direction of the current flowing through the movable contact 23 and the arrangement of the pair of permanent magnets 29, 29 with respect to the movable contact 23 (the magnetic field generated between the permanent magnets 29, 29) according to Fleming's left-hand rule. Direction).

  As described above, in the DC-DC converter 11, a ripple current occurs. This ripple current is superimposed on the DC current and flows through the relays 13 and 14 (movable contacts 23). Since the magnitude of the ripple current changes periodically, the current flowing through the movable contact 23 changes periodically, and the electromagnetic force acting on the movable contact 23 changes (increases or decreases). The change in the electromagnetic force causes the movable contact 23 that is in contact with the fixed contacts 21 and 22 to vibrate, thereby generating a vibration sound. In particular, in the power supply device 1 using the high-voltage battery 10 to drive the electric motor 2, the DC current flowing through the movable contacts 23 of the relays 13 and 14 is large (particularly, charging is performed to drive the electric motor 2 during discharging. Since the current (maximum value) flowing is larger than at the time, the ripple current also increases, and the vibration noise increases. The power supply device 1 has a configuration for suppressing this vibration sound.

  An arrangement method of the first relay 13 and the second relay 14 for suppressing the vibration noise will be described with reference to FIG. FIG. 4 is a diagram illustrating an arrangement of the first relay 13 and the second relay 14 in the power supply device 1 according to the embodiment. FIG. 4 also shows a part of the inside of the relays 13 and 14 (fixed contacts 21 and 22 and the movable contact 23), in which the movable contact 23 is in contact with the fixed contacts 21 and 22.

  The first relay 13 and the second relay 14 are attached to, for example, the same side surface 40 of the battery box. The first relay 13 and the second relay 14 have a contact surface C1 between the movable contact 23 of the first relay 13 and the fixed contacts 21 and 22, and a contact surface between the movable contact 23 of the second relay 14 and the fixed contacts 21 and 22. C2 are arranged in parallel so as to face each other. Further, the first relay 13 and the second relay 14 are arranged with an interval of an odd multiple of a half wavelength of the vibration sound (an integer multiple of the wavelength + half a wavelength). In particular, the first relay 13 and the second relay 14 are arranged such that the distance between the opposing contact surface C1 of the first relay 13 and the contact surface C2 of the second relay 14 is an odd multiple of a half wavelength of the vibration sound. Have been.

  The vibration sound generated by the first relay 13 and the vibration sound generated by the second relay 14 are generated by a periodic change of the ripple current. Therefore, the vibration sound generated by the first relay 13 and the vibration sound generated by the second relay 14 have the same frequency as the frequency of the ripple current. The frequency of the ripple current is the same as the switching frequency of the switching element of the DC-DC converter 11 as described above. The wavelength of the vibration sound is a value obtained by dividing the sound speed by the frequency of the vibration sound. Therefore, the wavelength and half wavelength of the vibration sound can be calculated using the switching frequency of the switching element of the DC-DC converter 11 and the sound speed. For example, assuming that the switching frequency (frequency of the vibration sound) is 10 kHz and the sound speed is 340 m / s, the wavelength of the vibration sound is 34 mm, and the half wavelength is 17 mm.

  Since the first relay 13 and the second relay 14 are arranged with an interval of an odd multiple of a half wavelength of the vibration sound, the sound wave of the vibration sound transmitted from the first relay 13 to the second relay 14 and the second The sound wave of the vibration sound transmitted from the relay 14 to the first relay 13 has an opposite phase. In particular, the contact surface C1 on the first relay 13 (the location where the vibration sound occurs on the first relay 13) and the contact surface C2 on the second relay 14 (the location where the vibration sound occurs on the second relay 14) face each other. The vibration sound from the first relay 13 is easily transmitted toward the contact surface C2 of the second relay 14, and the vibration sound from the second relay 14 is easily transmitted to the contact surface of the first relay 13. It is easy to transmit in the direction of C1. Further, the distance between the opposing contact surface C1 of the first relay 13 and the contact surface C2 of the second relay 14 is arranged so as to be an odd multiple of a half wavelength of the vibration sound. And the sound wave of the vibration sound from the second relay 14 has exactly the opposite phase. As a result, the vibration sound from the first relay 13 and the vibration sound from the second relay 14 cancel each other, and the magnitude (sound pressure) of the vibration sound decreases. In addition, in order to cancel the vibration sound from the first relay 13 and the vibration sound from the second relay 14, in addition to the cancellation of the sound wave of the vibration sound transmitted directly in the atmosphere, the wave transmitted through the plate of the side surface 40 is used. There are also cancellations.

  In FIG. 4, a solid line indicated by a reference sign W1 indicates a sound wave of the vibration sound from the first relay 13, and a broken line indicated by a sign W2 indicates the sound wave of the vibration sound from the second relay 14. In the case of the example shown in FIG. 4, the distance between the contact surface C1 of the first relay 13 and the contact surface C2 of the second relay 14 is five times the half wavelength of the vibration sound. The sound wave W1 has just reached the contact surface C1 of the second relay 14 from the contact surface C1 of the first relay 13 at 2 × wavelength + half wavelength. The sound wave W2 has just reached the contact surface C1 of the first relay 13 from the contact surface C2 of the second relay 14 at 2 × wavelength + half wavelength. The sound waves W1 and W2 have antinodes exactly opposite in phase, and cancel each other out.

  According to the power supply device 1 according to the embodiment, the first relay 13 and the second relay 14 are arranged at an interval of an odd multiple of a half wavelength of the vibration sound, so that a member for sound countermeasures is not separately provided. In addition, vibration noise (abnormal noise) generated in the relays 13 and 14 by the ripple current in the connected state can be suppressed. Since it is not necessary to provide a noise countermeasure member to suppress vibration noise, cost and weight do not increase.

  According to the power supply device 1 according to the embodiment, by using the switching frequency and the sound speed of the switching element of the DC-DC converter 11, the wavelength and half wavelength of the vibration sound can be accurately obtained. For example, when the switching frequency of the DC-DC converter 11 is determined at the time of design, a half wavelength of the vibration sound can be calculated using the switching frequency, and the interval between the first relay 13 and the second relay 14 can be determined.

  According to the power supply device 1 according to the embodiment, by arranging the contact surface C1 of the first relay 13 and the contact surface C2 of the second relay to face each other, the vibration sound generated by the first relay 13 is reduced. The vibration sound generated in the second relay 14 is easily transmitted in the direction of the contact surface C1 of the first relay 13, and the effect of suppressing the vibration noise can be enhanced. Further, according to the power supply device 1 according to the embodiment, the interval between the contact surface C1 of the first relay 13 and the contact surface C2 of the second relay 14 is set to be an odd multiple of a half wavelength of the vibration sound. By arranging, the sound wave of the vibration sound generated by the first relay 13 and the sound wave of the vibration sound generated by the second relay 14 have exactly opposite phases, and the effect of suppressing the vibration sound can be further enhanced.

  As described above, the embodiments of the present invention have been described. However, the present invention is not limited to the above embodiments, and various modifications are possible. For example, in the above-described embodiment, the present invention is applied to a vehicle including the electric motor 2 as a driving source. However, a power supply device including relays on a positive electrode side and a negative electrode side between a secondary battery and a transformer circuit may be applied to other than a vehicle. It is possible.

  In the above embodiment, the contact surface C1 of the first relay 13 and the contact surface C2 of the second relay 14 are opposed to each other, and the distance between the contact surface C1 and the contact surface C2 is an odd multiple of half a wavelength of the vibration sound. Although the arrangement is such that the first relay 13 and the second relay 14 can be arranged in such a manner that the distance between the first relay 13 and the second relay 14 is an odd multiple of a half wavelength of the vibration sound, Since the sound wave of the sound and the sound wave of the vibration sound of the second relay 14 have substantially opposite phases, the vibration sound can be suppressed. Further, even when the contact surface C1 of the first relay 13 and the contact surface C2 of the second relay 14 do not face each other, vibration noise can be suppressed. For example, the contact surface C1 and the contact surface C2 shown in FIG. May be arranged facing each other in opposite directions.

Reference Signs List 1 power supply device 2 electric motor 10 battery (secondary battery)
11 DC-DC converter (Transformer circuit)
DESCRIPTION OF SYMBOLS 12 Inverter 13 1st relay 14 2nd relay 20 Coil 21,22 Fixed contact 23 Movable contact 29 Permanent magnet

Claims (5)

A secondary battery, a transforming circuit, a first relay for switching a positive side of the secondary battery and the transforming circuit between a connected state and a cutoff state, and a connected state of a negative side of the secondary battery and the transforming circuit. And a second relay that switches to a cut-off state.
The first relay and the second relay move the movable contact in accordance with energization / de-energization of the coil, so that the movable contact contacts the fixed contact in the connected state, and the movable contact contacts the fixed contact in the interrupted state. A movable contact is configured to be separated from the fixed contact,
The first relay and the second relay are arranged at intervals of an odd multiple of half a wavelength of a vibration sound generated when a ripple current generated in the transformer circuit flows through the movable contact. And power supply.   The power supply device according to claim 1, wherein the half wavelength of the vibration sound is calculated using a switching frequency and a sound speed of a switching element of the transformer circuit.   The first relay and the second relay are arranged such that a contact surface between the movable contact and the fixed contact of the first relay and a contact surface between the movable contact and the fixed contact of the second relay face each other. The power supply device according to claim 1, wherein the power supply device is disposed in a power supply.   The first relay and the second relay are arranged such that an interval between the contact surface of the first relay and the contact surface of the second relay is an odd multiple of a half wavelength of the vibration sound. The power supply device according to claim 3, wherein: Installed in vehicles equipped with an electric motor as a power source,
The power supply device according to any one of claims 1 to 4, wherein the voltage transforming circuit boosts the voltage of the secondary battery when the secondary battery is discharged.

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