JP2014217215A - Vibration reduction method, vibration reduction device and hybrid vehicle with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate influences by disturbance vibrations to a vibration using an electric motor as a vibration source, to stably generate an antiphase signal corresponding to the vibration of the vibration source, and to certainly reduce regeneration sound in a structure in which regenerative brake for collecting power by actuating the electric motor as a power generator is performed.SOLUTION: A vibration reduction device 1 reduces regeneration sound to be generated by regenerative brake for collecting power by actuating an electric motor 2 as a power generator, comprises: a current sensor 3 which detects a rotation signal to be generated by rotation of the electric motor 2; a harmonic wave generation part 4 which generates a six-times harmonic signal which is a signal of six-times harmonic waves among harmonic waves having frequencies of integer multiples of reference waves of the rotation signal on the basis of the rotation signal of the current sensor 3; a fixation filter 5 which generates an antiphase signal which is the opposite phase to that of the six-times harmonic signal; and an actuator drive circuit 6 and an actuator 7 which generate a vibration with the opposite phase to that of the regeneration sound on the basis of the antiphase signal. The vibration reduction device 1 cancels and reduces the regeneration sound by the vibration with the opposite phase.

Description

  The present invention relates to a vibration reduction method, a vibration reduction device, and a hybrid vehicle equipped with the vibration reduction method for reducing vibration using an electric motor (rotary electric machine) that generates rotational force by electromagnetic force as a vibration source. Specifically, a vibration reduction method, a vibration reduction device, and a vibration reduction method that are used to reduce regenerative sound that occurs when the electric motor is operated as a generator and power is recovered during deceleration of a vehicle or the like that includes an electric motor as a drive source, etc. The present invention relates to a hybrid vehicle equipped with the same.

  Conventionally, regenerative sound is one of noises generated in vehicles such as automobiles. Regenerative sound, for example, a hybrid vehicle or an electric vehicle, such as a motor, that is, a vehicle equipped with an electric motor (rotary electric machine) that generates rotational force by electromagnetic force as a drive source, collects electric power by operating the electric motor as a generator when the vehicle decelerates This is a vibration sound generated using the electric motor as a vibration source.

  Specifically, a vehicle including an electric motor as a drive source, such as a hybrid vehicle or an electric vehicle, is driven using a motor as a drive source and propelled by driving wheels with a driving force obtained by the electric motor when propelling the vehicle. On the other hand, when the vehicle decelerates, the motor is operated as a generator, and mechanical power transmitted from the wheel to the motor is converted into electric power, that is, kinetic energy is converted into electric energy, thereby generating braking force on the wheel. Thus, the vehicle is decelerated and so-called regenerative braking (regenerative braking) is performed in which the converted electric power (electric energy) is collected in the battery. When such regenerative braking is performed, regenerative sound is generated using the electric motor as a vibration source.

  Such regenerative sound using the motor as a vibration source is caused by vibration waves generated directly from the motor, or by vibration waves generated indirectly from the motor through an object such as a member supporting the motor. . Such regenerative sound may be harsh to the occupants in the vehicle, so it is desirable to reduce them as much as possible so as not to hurt the occupants.

  Here, as a technique for reducing the regenerative sound, there is a technique for reducing the noise of the electric motor by increasing the reduction ratio in the transmission that changes the rotational drive of the engine or the electric motor. However, even if the reduction ratio of the transmission changes, vibration due to the regenerative torque of the motor during regenerative braking does not necessarily occur. Therefore, even if such technology causes vibration due to regenerative torque, this vibration is transmitted. As a result, regenerative sound is generated.

  Therefore, conventionally, the noise is reduced by using a technique for detecting vibration of an electric motor as a vibration source or vibration of an object such as a member supporting the electric motor with a vibration sensor and removing vibration noise as noise. Has been done. The vibration noise cancellation technique using the vibration sensor will be specifically described with reference to FIGS. 19 and 20.

  FIG. 19 shows a configuration in the case where the vibration sound directly generated from the electric motor 102 as the vibration source is silenced. In this case, the vibration of the electric motor 102 becomes a direct sound wave and a vibration sound is generated. As shown in FIG. 19, the vibration of the electric motor 102 is detected by a vibration sensor 103 attached to the electric motor 102. That is, the vibration sensor 103 detects the vibration of the electric motor 102 as a signal. As the vibration sensor 103, for example, a piezoelectric element, an acceleration sensor, a microphone, or the like is used. The detection signal output from the vibration sensor 103 is input to the adaptive filter 105, and a signal for vibrating the vibration actuator 107 is output from the adaptive filter 105, and the vibration actuator 107 is vibrated by this signal.

  The adaptive filter 105 is an LMS type learning filter using, for example, an LMS (Least Mean Square) adaptive algorithm. The adaptive filter 105 sequentially updates the filter coefficient based on the detection signal from the vibration sensor 103, and outputs an excitation signal having the same amplitude as that of the input detection signal based on the updated filter coefficient. . That is, the adaptive filter 105 generates a signal having a reverse phase so that the vibration (sound wave) emitted from the electric motor 102 is attenuated, and cancels the vibration sound of the electric motor 102 by the vibration actuator 107.

  The vibration actuator 107 is provided so as to be able to give vibration to the electric motor 102 by operating, receives an excitation signal output from the adaptive filter 105, and receives vibration of the electric motor 102 from the adaptive motor 105. The vibration of the electric motor 102 is canceled by applying the vibration having the same amplitude in the opposite phase. As the vibration actuator 107, for example, a magnetostrictive element or an electromagnetic actuator is used.

  In addition, in the configuration shown in FIG. 19, a vibration sensor 108 for detecting a vibration sound generated as a sound wave from the electric motor 102 is provided. The vibration sensor 108 functions as a so-called error microphone, and is provided at a position away from the electric motor 102 to some extent. The detection signal output from the vibration sensor 108 is added to the generation of an excitation signal based on the signal from the vibration sensor 103 attached to the electric motor 102 in the adaptive filter 105 so that the detection signal approaches zero. That is, the detection signal of the vibration sensor 108 is input to the adaptive filter 105 and reflected in the update of the filter coefficient in the adaptive filter 105, whereby feedback control is performed on the excitation signal from the adaptive filter 105 to the vibration actuator 107. As a result, the vibration actuator can be controlled in accordance with a change in the state of the electric motor 102. As the vibration sensor 108, for example, a piezoelectric element, an acceleration sensor, a microphone, or the like is used.

  FIG. 20 shows a configuration in the case where the vibration sound generated from the electric motor 102 as the vibration source through the object is silenced. In this case, the vibration of the electric motor 102 is transmitted through the support member 102a that supports the electric motor 102 to become a sound wave, and a vibration sound is generated. Note that components similar to those illustrated in FIG. 19 are denoted by the same reference numerals, and description thereof is omitted.

  As shown in FIG. 20, in silencing when vibration noise is generated through an object, the vibration actuator 107 for applying vibration in a phase opposite to that of the vibration source applies vibration to the support member 102 a by operating. It is provided so that it can. The vibration sensor 108 as an error microphone is used to detect vibration sound generated as a sound wave from the support member 102a. In the configuration as shown in FIG. 20, if the vibration path (see reference numeral L1) from the motor 102 that is the vibration source is long, the transfer function used for generating the excitation signal in the adaptive filter 105 becomes complicated accordingly. End up.

  For example, Patent Document 1 and Patent Document 2 are known as noise cancellation techniques for vibration noise using the vibration sensor as described above. These patent documents relate to a technique for reducing vehicle vibration by applying to the vehicle a vibration having an opposite phase to the vehicle vibration using an engine as a vibration source, and the vibration sensor. The structure provided with the actuator which vibrates a vehicle body based on the vibration signal from is shown.

  And in patent document 1, in the structure provided with a vibration sensor and an actuator as mentioned above, the 2nd vibration sensor is arrange | positioned in vibration generation parts other than the engine in a vehicle, and the disturbance vibration from this 2nd vibration sensor A technique for subtracting a signal from a vibration signal from a vibration sensor and correcting the vibration signal is disclosed. According to such a technique, it is considered that the vibration reduction operation can be performed while avoiding the adverse effect due to the disturbance by creating the excitation signal based on the vibration signal from which the disturbance is excluded and performing the vibration reduction control.

  Further, in Patent Document 2, when the vibration detected by the vibration sensor exceeds a certain value, a portion exceeding the certain value is cut as a voltage signal, and the distortion attached to the vehicle door or the like by the cut signal. A technique is disclosed in which an actuator generates a vibration having a phase opposite to that detected by a vibration sensor to cancel and attenuate the vibration of the vehicle body. With this technique, the strain actuator is protected so that a voltage higher than a predetermined voltage is not applied to the strain actuator.

JP-A-6-33978 Japanese Patent Laid-Open No. 2002-2542

  In the prior art as described above, a vibration sound is detected by a vibration sensor such as an acceleration sensor or a microphone, and a signal for canceling the vibration sound in an opposite phase is generated based on the detection signal.

  However, in an actual vehicle, there is a vibration of the vehicle while the vehicle is running, so the vibration generated from the vibration source such as an engine or an electric motor detected by the vibration sensor is much larger than the vibration of the vibration source. The vehicle vibrations are mixed as disturbance vibrations. Thus, when disturbance vibration is included in the vibration detected by the vibration sensor, the signal having the opposite phase for canceling the vibration sound does not correspond to the actual vibration of the vibration source.

  For this reason, when the vibration noise is eliminated in the opposite phase as described above, in order to eliminate the influence of the vibration of the vehicle at the time of traveling, a filtering process is performed on the detection signal by the vibration sensor or the period which is a characteristic of the vibration generated from the vibration source Therefore, it is necessary to take measures such as using an adaptive filter that emphasizes the signal component having the characteristics. However, due to the fact that signals with periodicity are mixed in the vibration of the running vehicle and the vibration of the vehicle during running is much larger than the vibration of the vibration source, etc. It is difficult to mute the vibration noise caused by the vibration of the vibration source in an actual vehicle by measures using signal processing in the processing or adaptive filter.

  The present invention has been made in view of the above-described problems, and in a configuration in which regenerative braking is performed in which an electric motor is operated as a generator to collect electric power, it is based on disturbance vibration with respect to vibration using the electric motor as a vibration source. A vibration reduction method, a vibration reduction device, and a vibration reduction method that can eliminate the influence, can stably generate an antiphase signal corresponding to the vibration of the vibration source, and can reliably reduce the regenerative sound. An object is to provide a hybrid vehicle.

  A vibration reduction method according to the present invention is a vibration reduction method for reducing regenerative sound generated by regenerative braking in which an electric motor is operated as a generator to collect electric power, and detects a rotation signal generated by rotation of the electric motor, Based on the rotation signal, a harmonic signal having a harmonic frequency that is a predetermined multiple of a predetermined number of harmonics having a frequency that is an integral multiple of the fundamental frequency of the rotation signal is generated, and the phase of the harmonic signal is reversed. Generating an antiphase signal, generating a vibration having an antiphase with the regenerative sound based on the antiphase signal, and canceling and reducing the regenerative sound by the antiphase vibration. is there.

  The vibration reduction device according to one aspect of the present invention detects a vibration of the vibration unit that generates the regenerative sound, generates a vibration signal, and generates a signal having a frequency that matches the predetermined number of times from the vibration signal. The harmonic signal is controlled by an adaptive filter so that the extracted signal of the frequency is minimized.

  A vibration reduction device according to the present invention is a vibration reduction device that reduces regenerative sound generated by regenerative braking that operates an electric motor as a generator and collects electric power, and detects rotation signals generated by rotation of the electric motor. And a harmonic generation unit that generates a harmonic signal of a harmonic having a predetermined number of times a predetermined frequency among harmonics having a frequency that is an integral multiple of the fundamental wave of the rotation signal, based on the rotation signal; An anti-phase signal generating unit that generates an anti-phase signal having a phase opposite to that of the harmonic signal, and a vibration generating unit that generates an anti-phase vibration based on the anti-phase signal, The regenerative sound is canceled and reduced by antiphase vibration.

  The vibration reduction device according to an aspect of the present invention is configured to detect a vibration of the vibration unit that generates the regenerative sound and generate a vibration signal, and the vibration signal matches the frequency of the predetermined number of times. A signal extraction unit that extracts a signal of a frequency, and the antiphase signal generation unit converts the harmonic signal by an adaptive filter so that the signal of the frequency extracted by the signal extraction unit is minimized. It is characterized by controlling.

  In the vibration reducing device according to one aspect of the present invention, the vibration generating unit is configured to generate the magnetostrictive actuator based on the magnetostrictive actuator that vibrates in contact with the vibrating unit that generates the regenerative sound and the antiphase signal. And an actuator drive circuit for driving the actuator.

  A hybrid vehicle according to the present invention is a hybrid vehicle including the vibration reducing device, and is connected to an engine, a power generation motor generator connected to the engine and mainly used for power generation, and connected to the engine. A driving motor generator used for obtaining a driving force of the axle, wherein the power generation motor generator is the electric motor.

  According to the present invention, in a configuration in which regenerative braking is performed in which an electric motor is operated as a generator and power is collected, the influence of disturbance vibration on vibration using the electric motor as a vibration source can be eliminated, and the vibration of the vibration source can be handled. Thus, the signal having the opposite phase can be stably generated, and the regenerative sound can be reliably reduced.

The figure which shows an example of the analysis result of the in-vehicle sound which generate | occur | produces in a hybrid vehicle in description of the principle of this invention. The figure which shows an example of the frequency analysis result of the current signal of a motor generator in description of the principle of this invention. The figure which shows an example of the analysis result of the current signal of a motor generator in description of the principle of this invention. Explanatory drawing about the vibration reduction method which concerns on 1st Embodiment of this invention. The figure which shows the structure of the vibration reduction apparatus which concerns on 1st Embodiment of this invention. The figure which shows an example of a structure of the harmonic production | generation part of the vibration reduction apparatus which concerns on 1st Embodiment of this invention. The figure which shows an example of the 6th harmonic signal produced | generated by the harmonic production | generation part of the vibration reduction apparatus which concerns on 1st Embodiment of this invention. The figure which shows another example of a structure of the harmonic production | generation part of the vibration reduction apparatus which concerns on 1st Embodiment of this invention. The figure which shows an example of a structure of the actuator of the vibration reduction apparatus which concerns on 1st Embodiment of this invention. The figure which shows the modification of the vibration reduction apparatus which concerns on 1st Embodiment of this invention. The figure which shows an example of a structure of the harmonic production | generation part in the modification of the vibration reduction apparatus which concerns on 1st Embodiment of this invention. The figure which shows the other modification of the vibration reduction apparatus which concerns on 1st Embodiment of this invention. Explanatory drawing about the simulation of the vibration reduction method which concerns on 2nd Embodiment of this invention. The figure which shows the simulation result by the vibration reduction method which concerns on 2nd Embodiment of this invention. The figure which shows the structure of the vibration reduction apparatus which concerns on 2nd Embodiment of this invention. Explanatory drawing of the function of the adaptive filter which concerns on 2nd Embodiment of this invention. The block diagram which shows an example of the structure for the coefficient update of the adaptive filter which concerns on 2nd Embodiment of this invention. The figure which shows the structure of the hybrid vehicle which concerns on 3rd Embodiment of this invention. Explanatory drawing about an example of the conventional noise reduction technique. Explanatory drawing about an example of the conventional noise reduction technique.

  The present invention reduces the regenerative sound by applying a vibration having a phase opposite to that of the regenerative sound to the vibration part that generates the regenerative sound by using harmonics having a frequency several times the fundamental wave of the rotation signal of the motor. It is going to plan.

  Here, in describing the embodiment of the present invention, the principle of the present invention will be described. In a hybrid vehicle having an engine (internal combustion engine) and a motor generator as drive sources, a waveform (graph shape) obtained as a result of frequency analysis of regenerative sound as noise generated during regenerative braking performed when the vehicle is decelerated is obtained. The phenomenon that the current waveform (or voltage waveform) generated from the motor matches the waveform (graph shape) obtained as a result of frequency analysis of harmonics with a frequency that is a predetermined number of times higher than the fundamental wave. It was done. The present invention has been made paying attention to such a phenomenon. Some hybrid vehicles have two motor generators, which are a motor generator for driving mainly used to obtain driving force for driving an axle and a motor generator for power generation mainly used for power generation. is there. These motor generators have a three-phase (U-phase, V-phase, W-phase) AC synchronous configuration, and employ PWM (Pulse Width Modulation) control as a drive control method. The following phenomenon was found in the hybrid vehicle having such a configuration.

  FIG. 1 is a graph showing an example of an acoustic analysis result of in-vehicle sound at the time of deceleration generated in the hybrid vehicle having the above-described configuration. In the graph shown in FIG. 1, the horizontal axis is time and the vertical axis is frequency. In the graph shown in FIG. 1, the background color (brightness) indicates power (acoustic power). The lighter the color (brighter), the higher the power, and the darker (darker) the color, the smaller the power.

  As shown in the graph of FIG. 1, in the hybrid vehicle according to this example, regenerative sound observed in the vehicle is generated when the vehicle is decelerated. In the graph of FIG. 1, a linear portion having a locally high power indicated by an arrow A <b> 1 is a portion representing a regenerative sound. From FIG. 1, it can be seen that the frequency of the regenerative sound gradually decreases with time. Specifically, in the example shown in FIG. 1, when the vehicle starts decelerating, a sound of about 1.5 KHz is generated at the same time as the start of decelerating, and the sound is reduced as the vehicle decelerates (reduction in the number of revolutions). The frequency has dropped from about 1.5 KHz to about 60 Hz. Further, it can be seen from the graph of FIG. 1 that the regenerative sound generated here is a single frequency waveform (= SIN waveform) without harmonics in terms of frequency characteristics.

  The regenerative sound generated in the hybrid vehicle according to this example is caused by harmonics generated in the motor generator when the vehicle is decelerated. In particular, the regenerative sound shown in FIG. 1 is generated by using a power generation motor generator (hereinafter referred to as “MG1”) among the two motor generators included in the hybrid vehicle as described above. This is supported by the frequency analysis result of the current signal (current waveform) of the motor generator shown in FIG. It can be said that the harmonics generated in the motor generator are sine waves having a frequency that is an integral multiple of the fundamental wave included in the rotation signal of the motor generator.

  FIG. 2A shows an example of the result of frequency analysis of the current signal of MG1 during deceleration of the hybrid vehicle by FFT (Fast Fourier Transform). FIG. 2B shows the result of frequency analysis of the current signal of the drive motor generator (hereinafter referred to as “MG2”) of the two motor generators included in the hybrid vehicle when the hybrid vehicle is decelerated by FFT. An example is shown. 2A and 2B, the horizontal axis represents frequency, and the vertical axis represents vibration intensity (vibration level) (dB).

  From FIG. 2A, it can be seen that in MG1, many harmonics are generated when the hybrid vehicle is decelerated. In the frequency analysis result shown in FIG. 2A, the harmonic appears as a needle-like local peak. In the example shown in FIG. 2A, there are second to seventh harmonics h2 to h7 in order from the lower frequency side, with the portion indicated by reference numeral h1 as the fundamental wave. The harmonics generated in MG1 as described above cause regenerative sound as shown in FIG. On the other hand, from the frequency analysis result of MG2 shown in FIG. 2 (b), it can be seen that in MG2, harmonics that cause regenerative sound like MG1 are not generated when the hybrid vehicle is decelerated. From these analysis results, it can be said that the regenerative sound as shown in FIG. 1 is generated using MG1 as a vibration source.

  FIG. 3 shows an example of the analysis result of the current signal (current waveform) of MG1. As in the graph shown in FIG. 1, the graph shown in FIG. 3 has time on the horizontal axis and frequency on the vertical axis, and indicates power (acoustic power) by background color (brightness). Further, the analysis result of FIG. 3 shares the time axis with the analysis result of FIG. That is, the analysis results shown in FIGS. 1 and 3 are based on the data measured at the same time.

  In the graph shown in FIG. 3, there are a plurality of mountain-like linear portions that are locally high in power and are represented by white lines. These mountain-shaped linear portions represent harmonics generated in MG1 as described above. Therefore, in the example shown in FIG. 3, among the plurality of mountain-shaped linear portions, the linear portion indicated by the symbol J1 having the lowest frequency is used as the fundamental wave, and the second to seventh harmonics are sequentially arranged from the lowest frequency side. Waves J2 to J7 etc. exist. The waveform (the shape of the graph) representing these harmonics has a common peak position on the time axis (horizontal axis). Note that the brightness (sharpness) of the linear portion corresponding to each harmonic shown in FIG. 3 corresponds to the value on the vertical axis in the graph of FIG. The seventh harmonic has a higher vibration level than the even-numbered (2, 4, 6th) harmonics, and is clearly shown in FIG. Further, MG2 was also analyzed for the current waveform at the same time as in the case of MG1, but no harmonics as shown in FIG. 3 appeared in the result. From this, MG2 is also a regenerative sound. It can be said that this is not the cause.

  Then, from the waveform as the frequency analysis result of the in-vehicle sound shown in FIG. 1 and the waveform as the frequency analysis result of the harmonic of MG1 shown in FIG. 3, the sixth harmonic among the harmonics shown in FIG. It can be seen that the frequency of the sixth harmonic indicated by reference numeral J6 completely matches the frequency of the vehicle interior sound shown in FIG. That is, the waveform as the frequency analysis result of the regenerative sound generated during deceleration of the hybrid vehicle and the waveform as the result of the frequency analysis of the sixth harmonic generated in MG1 during deceleration also coincide with each other. The difference between the temporal change in the frequency shown in FIG. 1 and the temporal change in the frequency shown in FIG. 3 is due to the difference in the timing of measuring the in-vehicle sound shown in FIG. 1 and the harmonics shown in FIG. When these are measured at the same time, the temporal changes in frequency are completely the same. Thus, in a hybrid vehicle including the engine, MG1, and MG2, the waveform of the regenerative sound observed in the vehicle when the vehicle decelerates matches the waveform of the sixth harmonic generated in MG1. This is considered to be caused by the configuration of a motor generator of an AC synchronous type (U phase, V phase, W phase), a motor generator drive control system such as PWM control, and the like.

  As described above, the phenomenon that occurs in the hybrid vehicle including the engine, MG1, and MG2, that is, the phenomenon that the waveform of the sixth harmonic generated in MG1 when the vehicle decelerates coincides with the waveform of the regenerative sound that is also generated during deceleration. Used in the operating principle of vibration reduction according to the invention. That is, from the current waveform signal of MG1 when the vehicle is decelerating, the nth harmonic (nth harmonic) that matches the waveform of the regenerative sound that is also generated when decelerating (n: integer, n = 6 in the above example). By extracting the signal extracted only from the frequency component of this and using the signal to give the vibration part of the nth harmonic in reverse phase to the vibration part that generates the regenerative sound, without being affected by disturbance vibration Regenerative sound (regenerative vibration) can be attenuated stably. In addition, with respect to the anti-phase vibration of the nth harmonic, instead of directly applying the anti-phase vibration to the vibration part that generates the regenerative sound, the anti-phase vibration is generated as a sound wave in the vehicle. It is also possible to mute the regenerative sound using acoustic equipment.

  Embodiments of the present invention will be described below. In the embodiment of the present invention, a case will be described in which the sixth harmonic (sixth harmonic) is employed as the nth harmonic used for reducing the regenerative sound, following the example of the hybrid vehicle described above. . However, the harmonic used for reducing the regenerative sound in the present invention is not limited to the sixth harmonic, and the nth harmonic determined in advance depending on the configuration of the motor, the configuration of the vehicle including the motor, and the like. Is used as appropriate.

[First Embodiment]
A first embodiment of the present invention will be described. The vibration reducing method according to the present embodiment reduces regenerative sound generated by using an electric motor as a vibration source by regenerative braking in which an electric motor that generates rotational force by electromagnetic force is operated as a generator to collect electric power. That is, in the vibration reducing method of the present embodiment, the electric motor that generates the rotational force by the electromagnetic force is a so-called rotating electric machine, for example, a motor generator provided in a hybrid vehicle or an electric vehicle. In particular, in the example of the hybrid vehicle as described above, MG1 that is the vibration source of the regenerative sound of the two motor generators corresponds to the electric motor in the vibration reduction method according to the present embodiment.

  As shown in FIG. 4, in the vibration reducing method according to the present embodiment, first, a rotation signal generated by the rotation of the electric motor is detected (S10). The rotation signal of the electric motor is detected, for example, by detecting a current waveform or a voltage waveform of the electric motor with a current sensor or a voltage sensor, or by detecting a pulse waveform with a rotary encoder. The motor rotation signal detected here (hereinafter referred to as “motor rotation signal”) is detected as a waveform signal such as a current waveform when a current sensor or the like is used as in the former, and a rotary encoder as in the latter is detected. When used, it is detected as a pulse signal.

  Next, a sixth harmonic signal is generated based on the detected motor rotation signal (S20). Here, based on the motor rotation signal detected in step S10, of the harmonics having a frequency that is an integral multiple of the fundamental wave of the motor rotation signal, a harmonic having a predetermined number of times of the harmonic, that is, the present embodiment. Then, a harmonic signal of the sixth harmonic (hereinafter referred to as “sixth harmonic signal”) is generated.

  The generation of the 6th harmonic signal in step S20 is appropriately performed using a known method. Specifically, when the motor rotation signal is detected as a waveform signal such as a current waveform by the current sensor in step S10, the waveform signal is obtained by a method using PLL (Phase Locked Loop) control or FFT (Fast Fourier Transform). Calculation processing is performed by the method used, and a 6th harmonic signal is detected or generated from the motor rotation signal. When the motor rotation signal is detected as a pulse signal by the rotary encoder in step S10, the pulse signal is frequency-controlled by an address counter, a ROM table, etc., and then converted from a digital signal to an analog signal. A double harmonic signal is detected or generated. The sixth harmonic signal generated here is, for example, a SIN wave signal having a frequency six times the fundamental wave of the motor rotation signal of the waveform signal.

  Subsequently, an antiphase signal having a phase opposite to that of the 6th harmonic signal is generated from the generated 6th harmonic signal (S30). That is, here, the phase of the 6th harmonic signal generated in step S20 is inverted, and an antiphase signal having a phase opposite to that of the 6th harmonic signal is generated. The anti-phase signal generated here is a signal having the same phase and the same amplitude as that of the sixth harmonic signal.

  The generation of the antiphase signal is performed using, for example, a fixed filter in which the filter coefficient forming the transfer function is fixed. That is, in the fixed filter, the filter coefficient is set in advance so that the input 6th harmonic signal becomes an antiphase signal. Then, an antiphase signal is output as a control signal (excitation signal) from the fixed filter.

  Next, based on the generated reverse phase signal, a vibration having a phase opposite to that of the regenerative sound is generated (S40). Here, generation of vibration by the actuator or generation of vibration by the speaker is performed based on the antiphase signal generated in step S30.

  When vibration is generated by an actuator, for example, an actuator that vibrates in contact with a vibration unit that generates a regenerative sound (hereinafter referred to as “regenerative sound generation unit”), and an actuator drive circuit that drives the actuator, A configuration including is used. In this case, the antiphase signal generated by the fixed filter as described above is input to the actuator drive circuit, and the actuator drive circuit controls the actuator based on the input antiphase signal. The actuator generates vibration having a phase opposite to that of the regenerative sound under the control of the actuator driving circuit. Here, for example, a magnetostrictive actuator, an electromagnetic actuator, a piezoelectric element actuator, a ceramic actuator, or the like is appropriately used as an actuator that applies an antiphase vibration to the regenerative sound generator.

  When vibration is generated by the speaker, the antiphase signal generated by the fixed filter as described above is appropriately amplified by an amplifier or the like, and is emitted from the speaker as a sound wave having an antiphase with the regenerative sound. That is, in this case, the sound wave emitted from the speaker is generated as vibration having a phase opposite to that of the regenerative sound. Here, as a speaker that emits a sound wave having a phase opposite to that of the regenerative sound, for example, an existing speaker provided in the vehicle in a hybrid vehicle is used, or a dedicated speaker is used separately.

  Then, the regenerated sound is canceled and reduced by the generated antiphase vibration (S50). Here, the regenerative sound is reduced by canceling the regenerative sound by the antiphase vibration generated by the actuator or the speaker in step S40.

  Specifically, when the vibration is generated by the actuator as described above, the actuator generates a regenerative sound with respect to the regenerative sound generator, for example, the motor itself serving as a vibration source or a support member that supports the motor. Gives anti-phase vibration. Thereby, the vibration of the regenerative sound generator is canceled and the regenerative sound is reduced.

  In addition, when vibration is generated by the speaker as described above, the speaker emits a sound wave having a phase opposite to that of the regenerative sound, thereby canceling the regenerative sound generated as the in-vehicle sound in the hybrid vehicle. In other words, in this case, vibration having a phase opposite to that of the regenerative sound generated as a sound wave by the speaker acts on the regenerative sound using air as a medium, and the regenerative sound is muted.

  According to the vibration reduction method of the present embodiment for reducing regenerative sound as described above, in a configuration in which regenerative braking is performed in which the electric motor is operated as a generator and power is collected, disturbance to vibration using the electric motor as a vibration source is performed. It is possible to eliminate the influence of vibration, stably generate an antiphase signal corresponding to the vibration of the vibration source, and reliably reduce regenerative sound.

  In particular, the sixth harmonic signal of the electric motor used for generating the vibration having the opposite phase to the regenerative sound in the vibration reduction method of the present embodiment is based on the signal generated from the electric motor itself that is the vibration source of the regenerative sound. It is not affected by disturbance vibration such as vehicle vibration during traveling that occurs in an actual vehicle. For this reason, according to the vibration reduction method of the present embodiment, compared to a method using a vibration sensor as in the prior art, vibrations having a phase opposite to that of the regenerative sound are stably generated without being affected by disturbance vibration. be able to. In addition, according to the vibration reduction method of the present embodiment, the vibration sensor as in the prior art is not necessary, and calculation by an adaptive filter having a relatively complicated structure is not required. It is possible to realize this configuration with a very simple configuration.

  As an example of a device configuration for performing the vibration reduction method of the present embodiment as described above, a vibration reduction device according to the present embodiment will be described.

  As shown in FIG. 5, the vibration reducing apparatus 1 according to the present embodiment has a regenerative sound generated using the electric motor 2 as a vibration source by regenerative braking that operates the electric motor 2 that generates a rotational force by electromagnetic force as a generator and collects electric power. Is reduced. In the present embodiment, the electric motor 2 corresponds to MG1 of the two motor generators in the example of the hybrid vehicle as described above.

  The electric motor 2 is supported by the support member 2a in the hybrid vehicle. For this reason, the regenerative sound generated using the electric motor 2 as a vibration source is mainly generated as the vibration sound of the support member 2a to which the vibration of the electric motor 2 is transmitted. That is, the vibration of the electric motor 2 is transmitted through the support member 2a to become a sound wave, and regenerative sound is generated. Therefore, in this embodiment, the support member 2a that supports the electric motor 2 as a vibration source serves as a regenerative sound generator.

  As described above, the vibration reduction device 1 according to the present embodiment cancels the vibration and gives the regenerative sound to the support member 2a of the electric motor 2 serving as the regenerative sound generation unit by applying a vibration having a phase opposite to that of the regenerative sound. Is reduced. The vibration reduction device 1 includes a current sensor 3, a harmonic generation unit 4, a fixed filter 5, an actuator drive circuit 6, and an actuator 7.

  The current sensor 3 is connected to the motor 2, detects the current of the motor 2 in real time, and outputs a current signal S 1 as a rotation signal (motor rotation signal) generated by the rotation of the motor 2. The current signal S1 output from the current sensor 3 is input to the harmonic generation unit 4. The frequency of the fundamental wave of the current signal S1 is the same as the rotation frequency of the electric motor 2. The current sensor 3 functions as a rotation detection unit that detects an electric motor rotation signal. The current sensor 3 is connected to the harmonic generation unit 4, and a current signal S 1 that is a detection signal from the current sensor 3 is input to the harmonic generation unit 4. The current sensor 3 is connected to an ECU (Electronic Control Unit) 8 for controlling the electric motor 2 in the hybrid vehicle, and the detection signal from the current sensor 3 is also used for controlling the hybrid vehicle.

  As the current sensor 3, for example, an existing current sensor included in a hybrid vehicle to which the vibration reduction device 1 of the present embodiment is applied can be used. In addition, a voltage sensor that detects the voltage of the electric motor 2 in real time may be used as the rotation detection unit. In this case, a voltage signal is detected as the motor rotation signal. In this case, an existing voltage sensor provided in the hybrid vehicle can be used.

  The harmonic generation unit 4 is based on the current signal S1 detected by the current sensor 3, and among the harmonics having a frequency that is an integral multiple of the fundamental wave of the current signal S1, the harmonics of a harmonic having a predetermined multiple of the predetermined frequency. A sixth harmonic signal S3, which is a wave signal, is generated. In the present embodiment, the motor rotation signal detected by the current sensor 3 is the current signal S1 of the motor 2. For this reason, the harmonic generation unit 4 generates and outputs a sixth harmonic signal S3 having a frequency six times the fundamental wave of the current signal S1 based on the current signal S1. Specifically, the harmonic generation unit 4 generates a sixth harmonic signal S3 during regenerative braking in the hybrid vehicle, that is, when the electric motor 2 (MG1) is decelerated. The harmonic generation unit 4 is connected to the fixed filter 5, and the 6th harmonic signal S3 generated in the harmonic generation unit 4 is input to the fixed filter 5.

  A specific configuration example of the harmonic generation unit 4 will be described with reference to FIGS. FIG. 6 shows an example of the configuration of the harmonic generation unit 4. In the configuration shown in FIG. 6, the harmonic generation unit 4 generates the 6th harmonic signal S3 by feedback control using PLL control.

  As shown in FIG. 6, in this configuration example, the harmonic generation unit 4 includes a zero-cross detection unit 11, a VCO (Voltage Controlled Oscillator) 12, a 1/6 counter 13, a phase comparison unit 14, and a PLL control unit. 15. The harmonic generation unit 4 receives an input of the current signal S <b> 1 as a detection signal from the current sensor 3 in the zero cross detection unit 11.

  The zero-cross detector 11 detects a zero-cross point of the current signal S1 and generates a rectangular wave signal S2 composed of binary signals (for example, binary values of H and L) corresponding to the polarities between adjacent zero-cross points. And output. That is, the sinusoidal current signal S1 input from the current sensor 3 to the harmonic generation unit 4 is converted by the zero cross detection unit 11 into a rectangular wave signal S2 in which the peak portion of the current signal S1 is H and the valley portion is L. Is done.

The VCO 12 is an oscillator (oscillation circuit) that outputs an AC signal having a frequency corresponding to a voltage (control voltage). In the VCO 12, when the applied control voltage V _VCO changes, the capacitance of the diode changes and the oscillation frequency changes. The VCO 12 generates, for example, a Sin wave as an output signal. The _{VCO 12} receives the control voltage V _VCO output from the PLL control unit 15. Therefore, the _{VCO 12} changes the capacitance of the diode according to the control voltage V _VCO from the PLL control unit 15.

The 1/6 counter 13 receives an AC signal output from the VCO 12 and converts the frequency of the AC signal. The 1/6 counter 13 divides the frequency of the AC signal input from the VCO 12 and outputs a rectangular wave signal having a frequency of 1/6. Therefore, if the frequency of the AC signal output from the VCO12 was _{f 1,} the frequency of the rectangular wave signal output from the 1/6 counter 13 becomes _f 1/6.

The phase comparison unit 14 is a circuit that converts a phase difference between two input rectangular wave signals into a voltage corresponding to the phase difference and outputs the voltage. The phase comparator 14 receives the rectangular wave signal S2 output from the zero cross detector 11 and the rectangular wave signal output from the 1/6 counter 13. Therefore, the phase comparator 14 compares the square wave signal S2 zero-cross detecting unit 11 outputs the two signals in phase with the frequency of the rectangular wave signal of f _1/6 to 1/6 counter 13 outputs, A voltage signal corresponding to these phase differences is output. Therefore, if the phases of the two signals match, the output of the phase comparator 14 becomes zero.

The PLL control unit 15 includes a rectangular wave signal S2 output from the zero cross detection unit 11 and input to the phase comparison unit 14, and a rectangular wave signal output from the 1/6 counter 13 and input to the phase comparison unit 14. It is an electronic circuit for generating a control voltage V _VCO output to the _VCO 12 so as to synchronize the phase. That is, the PLL control unit 15 controls the value of the control voltage V _VCO so that the voltage signal output from the phase comparison unit 14 becomes zero.

In the harmonic generation unit 4 having the above-described configuration, the AC signal having the frequency f ₁ output from the VCO 12 is 6 times higher than the current signal S 1 from the current sensor 3 input to the harmonic generation unit 4. Output as signal S3. That is, when the frequency of the current signal S1 input from the current sensor 3 harmonic generator 4 and the f _0, a frequency of the square wave signal S2 outputted from the zero-cross detector 11 also becomes f _0. Then, according to the PLL controller 15, so that the frequency of the rectangular wave signal S2 _{(f 0)} coincides with the frequency of the rectangular wave signal output from the 1/6 counter 13 _(f 1/6) in the phase comparator 14 Therefore, as a result, the phases of the two signals coincide with each other and f ₁ = 6f ₀ is obtained. Therefore, the output signal from the VCO 12 having the frequency f ₁ becomes a sixth harmonic signal S3 with respect to the current signal S1 having the frequency f ₀ which is an input signal from the current sensor 3, and the sixth harmonic signal S3 is generated as a harmonic. This is an output signal from the unit 4.

  In the configuration shown in FIG. 6, the signal input to the harmonic generation unit 4 may be a real-time voltage signal generated by detecting the applied voltage of the electric motor 2. In this case, in the vibration reducing device 1, a voltage sensor is provided instead of the current sensor 3, and a signal input to the zero cross detection unit 11 becomes a sinusoidal voltage signal detected by the voltage sensor.

  FIG. 7 shows an example of the waveform of the 6th harmonic signal S3 generated by using the PLL control by the configuration of the harmonic generation unit 4 as shown in FIG. The upper part of FIG. 7 is a current signal S1 that is a detection signal from the current sensor 3. On the other hand, the lower part of FIG. 7 is a sixth harmonic signal S3 generated by using PLL control with the current signal S1 as a fundamental wave. As can be seen from the waveform shown in FIG. 7, according to the configuration of the harmonic generation unit 4 using the PLL control as shown in FIG. 6, the current signal S <b> 1 containing a lot of noise is six times as large as a sine wave having a very low noise. A harmonic signal S3 can be generated.

  FIG. 8 shows another example of the configuration of the harmonic generation unit 4. In the configuration illustrated in FIG. 8, the harmonic generation unit 4 generates the 6th harmonic signal S3 by control using FFT (Fast Fourier Transform) and inverse FFT.

  As shown in FIG. 8, in this configuration example, the harmonic generation unit 4 includes an FFT calculation unit 21, a BIN selection unit 22, an inverse FFT calculation unit 23, and a phase adjustment unit 24. The harmonic generation unit 4 receives an input of the current signal S <b> 1 as a detection signal from the current sensor 3 in the FFT calculation unit 21 and the phase adjustment unit 24.

The FFT calculation unit 21 has a circuit configuration for performing fast Fourier transform processing (FFT calculation) on the input current signal S1. The FFT operation unit 21 generates and outputs a frequency spectrum signal by performing FFT calculation on the input current signal S1. The FFT calculation by the FFT calculation unit 21 is performed at a sampling period T with the frequency (f ₀ ) of the current signal S1 as a fundamental frequency.

  As shown in FIG. 8, the frequency spectrum 21S obtained by the fast Fourier transform processing by the FFT calculation unit 21 has a fundamental frequency (1 / T) and an integer multiple thereof (2 / T, 3 / T, 4 / T, ...) And represents BINi (i = 1, 2, 3,...) Corresponding to each frequency. Each BINi corresponds to a harmonic whose fundamental frequency is the frequency of the first BIN1. BINi (i = 1, 2, 3,...) Is a component having a plurality of predetermined widths arranged at equal intervals for each fundamental frequency in the frequency spectrum 21S. The FFT operation unit 21 outputs a frequency spectrum signal S4 for the frequency spectrum 21S obtained by the FFT calculation.

  The BIN selection unit 22 has a circuit configuration for receiving the frequency spectrum signal S4 output from the FFT calculation unit 21 and selecting the sixth BIN 6 from the frequency spectrum signal S4. That is, as described above, the frequency spectrum 21S obtained in the FFT operation unit 21 includes BINi (i = 1, 2, 3,...) Corresponding to the fundamental frequency and the integral multiple of these frequencies. Of these, only the sixth BIN 6, that is, the component corresponding to the sixth harmonic is selected by the BIN selection unit 22. In other words, the BIN selection unit 22 cuts a signal other than BIN6 that is the sixth component of the plurality of BINi included in the frequency spectrum signal S4, and extracts and outputs only the signal of the sixth BIN6.

  The inverse FFT operation unit 23 has a circuit configuration for receiving an input of the sixth BIN6 signal output from the BIN selection unit 22 and performing an inverse FFT calculation on the input signal. The inverse FFT operation unit 23 performs inverse FFT conversion on the input BIN6 signal, returns the BIN6 signal to an AC signal, and outputs an AC signal S5 having the same frequency as the sixth harmonic.

  The phase adjustment unit 24 adjusts the phase of the AC signal having the same frequency as the sixth harmonic output by the inverse FFT calculation unit 23 with the same signal as the input signal to the FFT calculation unit 21, that is, the current signal S1 as a reference. Circuit configuration. That is, the phase adjustment unit 24 adjusts the phase of the AC signal S5 from the inverse FFT calculation unit 23 so that the phase of the AC signal S5 output from the inverse FFT calculation unit 23 matches the phase of the current signal S1, Output the adjusted signal. Therefore, the current signal S1 input from the current sensor 3 to the harmonic generation unit 4 and the AC signal S5 having the same frequency as the sixth harmonic output by the inverse FFT calculation unit 23 are input to the phase adjustment unit 24. The The phase adjustment unit 24 adjusts the phase, for example, by detecting a zero cross point of the AC signal S5.

  With the configuration as described above, the AC signal output from the phase adjustment unit 24 is output as the sixth harmonic signal S3 with respect to the current signal S1 input to the harmonic generation unit 4. That is, the AC signal S5 output from the inverse FFT operation unit 23 is an AC signal having the same frequency as that of the sixth harmonic, and a signal obtained by matching the phase of the signal with the current signal S1 is obtained as the sixth harmonic signal S3. Is output.

  In the configuration shown in FIG. 8, as in the configuration shown in FIG. 6, the signal input to the harmonic generation unit 4 may be a real-time voltage signal. In this case, in the vibration reducing apparatus 1, a voltage sensor is provided instead of the current sensor 3, and a signal input to the FFT calculation unit 21 and the phase adjustment unit 24 becomes a sinusoidal voltage signal detected by the voltage sensor. .

  A 6th harmonic signal S3 is generated by the harmonic generation unit 4 having the configuration exemplified above. In the present embodiment, in the harmonic generation unit 4, a harmonic signal having a predetermined number of times of a predetermined number of harmonics having a frequency that is an integral multiple of the fundamental wave of the current signal S <b> 1 as the motor rotation signal. As described above, the sixth harmonic signal S3 is generated, but the present invention is not limited to this. That is, the harmonics used for reducing the regenerative sound in the present invention, that is, the harmonics generated in the harmonic generation unit 4 are not limited to the sixth harmonics, and the configuration of the motor and the vehicle including the motor Depending on the configuration, etc., a predetermined harmonic (n-th harmonic) of a predetermined number of times (n times) is appropriately used.

  For example, when the nth harmonic is generated in the configuration shown in FIG. 6, a 1 / n counter that uses 1 / n as the frequency of the AC signal input from the VCO 12 is used instead of the 1/6 counter 13. . When the nth harmonic is generated in the configuration shown in FIG. 8, the BIN selection unit 22 is configured to select the nth BINn from the frequency spectrum signal S4 obtained by the FFT calculation unit 21. .

  In addition, regarding the technique for generating a harmonic signal such as a 6th harmonic signal from the current signal obtained by the current sensor 3, the method and the configuration of the harmonic generation unit 4 described above are examples, and the harmonics As a technique for generating a signal, other methods and configurations may be adopted as appropriate. For example, using a microcomputer or the like, as described above, a zero-cross point is detected from the current signal input from the current sensor 3 to the harmonic generation unit 4 to generate a rectangular wave signal, and the pulse width ( A harmonic signal can be generated by measuring a frequency of one cycle, calculating a frequency based on the time of one cycle, and multiplying the frequency by a predetermined number (n times).

  The fixed filter 5 receives the input of the 6th harmonic signal S3 generated by the harmonic generation unit 4, and generates an antiphase signal having a phase opposite to that of the input 6th harmonic signal S3, that is, an excitation signal. Output. That is, the fixed filter 5 inverts the phase of the 6th harmonic signal S3 based on the 6th harmonic signal S3 generated by the harmonic generation unit 4, and has the same phase as that of the 6th harmonic signal S3. An excitation signal that is an amplitude signal is generated.

  The filter coefficient forming the transfer function in the fixed filter 5 is fixed, and the fixed filter coefficient is set in advance so that the input sixth harmonic signal S3 becomes an antiphase signal. The antiphase signal output from the fixed filter 5 becomes a control signal for the actuator drive circuit 6. As described above, in the vibration reduction device 1 according to the present embodiment, the fixed filter 5 generates an antiphase signal in which the phase of the sixth harmonic signal S3 generated by the harmonic generation unit 4 is reversed. It functions as a part.

  The actuator drive circuit 6 drives and controls the actuator 7 based on the antiphase signal generated by the fixed filter 5. That is, the actuator drive circuit 6 generates a drive signal for the actuator 7 based on the antiphase signal input from the fixed filter 5, and transmits the drive signal to the actuator 7. The vibration reducing apparatus 1 according to the present embodiment includes a magnetostrictive actuator (super magnetostrictive actuator) as the actuator 7. For this reason, the actuator drive circuit 6 generates and outputs a drive signal for driving and controlling the magnetostrictive actuator.

  Here, the configuration of the actuator 7 will be described with reference to FIG. As shown in FIG. 9, the magnetostrictive actuator 7 includes a giant magnetostrictive material 31 that is a rod-like magnetostrictive element, and a coil 32 provided around the giant magnetostrictive material 31.

  The giant magnetostrictive material constituting the giant magnetostrictive material 31 is generally an alloy of a rare earth element and iron, and changes in external dimensions such as expansion and contraction when a magnetic field is applied. The strain amount of the giant magnetostrictive material is about 1000 to 10,000 times that of a general magnetostrictive material such as an alloy such as nickel (Ni), iron (Fe), and cobalt (Co). As the giant magnetostrictive material constituting the giant magnetostrictive material 31, a material that exhibits giant magnetostriction at room temperature is used.

  In the actuator 7 of the present embodiment, the rod-shaped giant magnetostrictive material 31 expands and contracts by changing its length due to a change in the magnetic field generated by the coil 32 (see arrow C1). The giant magnetostrictive material 31 is provided in a state supported by a predetermined support member 33.

  The coil 32 is configured to apply a magnetic field to the giant magnetostrictive material 31. The coil 32 is provided around the giant magnetostrictive material 31 by, for example, being wound around a pipe-shaped magnetic member into which the giant magnetostrictive material 31 is inserted. The coil 32 is connected to the actuator drive circuit 6 via a lead wire (not shown), and receives a drive voltage from the actuator drive circuit 6 via the lead wire to generate a magnetic field applied to the giant magnetostrictive material 31. .

  In such a configuration, when a drive voltage is applied from the actuator drive circuit 6 to the coil 32, the magnetic field around the giant magnetostrictive material 31 changes and the giant magnetostrictive material 31 expands and contracts. The expansion / contraction operation of the giant magnetostrictive material 31 is transmitted to the support member 2a as vibration for canceling the regenerative sound, that is, vibration having a phase opposite to that of the regenerative sound.

  Therefore, the actuator 7 is provided so that the expansion / contraction operation of the giant magnetostrictive material 31 is transmitted to the support member 2a as vibration. Specifically, as shown in FIG. 5, the actuator 7 is provided in a state where the working end 7 a that is displaced and vibrates with the expansion and contraction operation of the giant magnetostrictive material 31 is in contact with the support member 2 a. The working end 7a of the actuator 7 is, for example, an end of a rod-shaped giant magnetostrictive material 31 or a movable member separate from the giant magnetostrictive material 31 that vibrates as the giant magnetostrictive material 31 expands and contracts. . By the magnetostrictive actuator 7 as described above, vibration having a phase opposite to that of the support member 2a that generates the regenerative sound is applied to the support member 2a that is the vibration unit that generates the regenerative sound.

  The actuator drive circuit 6 that drives the actuator 7 supplies a voltage signal (drive voltage) to be applied to the coil 32 to change the magnetic field for expanding and contracting the giant magnetostrictive material 31 as a drive signal. The actuator drive circuit 6 generates and outputs a voltage signal to be applied to the coil 32 of the actuator 7 based on the antiphase signal generated by the fixed filter 5. The actuator drive circuit 6 includes a circuit configuration such as an amplifier that amplifies the antiphase signal input from the fixed filter 5 and has a function as a power amplifier. The actuator 7 generates a vibration having a phase opposite to that of the sixth harmonic signal as a vibration corresponding to the signal input from the actuator driving circuit 6.

  As described above, in the vibration reduction device 1 of this embodiment, the actuator drive circuit 6 that drives the actuator 7 by the input signal (antiphase signal) from the fixed filter 5 and the support member 2a vibrate in contact. The configuration including the actuator 7 functions as a vibration generation unit that generates a vibration having a phase opposite to that of the regenerative sound caused by the vibration of the support member 2 a using the electric motor 2 as a vibration source based on the reverse phase signal generated by the fixed filter 5. . That is, the vibration generating unit is based on a magnetostrictive actuator 7 that vibrates in contact with the support member 2a, which is a regenerative sound generating unit, and a signal (antiphase signal) generated by the fixed filter 5. And an actuator drive circuit 6 for driving the actuator 7.

  And the vibration reduction apparatus 1 of this embodiment cancels and reduces a regenerative sound using the vibration produced | generated by the structure containing the actuator drive circuit 6 and the actuator 7. FIG. That is, the actuator 7 vibrates the support member 2a to cancel the vibration of the support member 2a using the electric motor 2 as a vibration source, thereby reducing regenerative sound. That is, the vibration reducing apparatus 1 having the above-described configuration detects the current of the electric motor 2 that is the vibration source of the regenerative sound by the current sensor 3, and the harmonic generation unit 4 uses the current signal in the frequency analysis result. A 6th harmonic signal that matches the waveform (frequency) of the regenerative sound is generated, the 6th harmonic signal is reversed in phase by the fixed filter 5, and a magnetostrictive signal is generated by the actuator drive circuit 6 based on the signal in the opposite phase. The actuator 7 is vibrated.

  The vibration obtained in this manner is a vibration having a phase opposite to that of the support member 2a using the electric motor 2 as a vibration source, and is applied to the support member 2a. As a result, as shown in FIG. 5, the vibration V1 (see arrow v1) of the support member 2a using the electric motor 2 as a vibration source is canceled by the antiphase vibration V2 (see arrow v2) applied by the actuator 7. . As a result, regenerative sound generated as vibration of the support member 2a of the electric motor 2 is reduced.

(Modification 1)
A modification of the vibration reducing device 1 of the present embodiment will be described with reference to FIGS. 10 and 11. The vibration reducing apparatus 1A according to this modification detects a rotation signal generated by the rotation of the electric motor 2 by detecting a pulse waveform using a rotary encoder. Therefore, as illustrated in FIG. 10, the vibration reduction device 1 </ b> A includes a rotary encoder 41 that detects a pulse waveform for the rotation of the electric motor 2 as a rotation detection unit that detects a rotation signal generated by the rotation of the electric motor 2.

  The rotary encoder 41 includes, for example, a light source, a light receiving element that receives light from the light source, and a slit member that allows light from the light source to pass or be shielded as the motor 2 rotates. A pulse signal corresponding to the rotation of the signal is output. That is, the rotary encoder 41 outputs a pulse signal as an electric motor rotation signal, and this pulse signal is input to the harmonic generation unit 4A. As the rotary encoder 41, for example, one having a resolution that outputs a signal of 100 to 200 pulses when the electric motor 2 rotates once is used.

  The harmonic generation unit 4A in this modification includes, for example, an address counter 42, a ROM table 43, and a DAC (D / A converter) 44 as shown in FIG. The harmonic generation unit 4 </ b> A receives the pulse signal input from the rotary encoder 41 in the address counter 42.

  The rotary encoder 41 is connected to the ROM table 43 via the address counter 42. The address counter 42 designates the address of the ROM table 43. The ROM table 43 reads and outputs the data at the designated address at a predetermined speed. The ROM table 43 stores in advance data such that a six-cycle AC signal can be obtained with respect to the pulse signal for one cycle of the electric motor 2 output from the rotary encoder 41. For example, when the rotary encoder 41 outputs a signal of 100 pulses by one rotation of the electric motor 2, the ROM table 43 stores data corresponding to each position of the waveform for six cycles of the fundamental wave in 100 addresses. Yes.

  For this reason, when the pulse signal of the rotary encoder 41 obtained by one rotation of the electric motor 2 is input, the ROM table 43 outputs a signal corresponding to a waveform corresponding to six cycles of the fundamental wave. In other words, a signal having a frequency six times the rotational frequency of the electric motor 2 is output as a digital signal from the ROM table 43 by the pulse signal of the rotary encoder 41 obtained by one rotation of the electric motor 2.

  The digital signal output from the ROM table 43 is converted into an analog signal by the DAC 44 and output as a 6th harmonic signal.

  In the configuration of this modification, as the motor 2 rotates, a signal having a frequency six times the fundamental wave is automatically generated by the ROM table 43. As in this modification, a 6th harmonic signal can be generated from the motor rotation signal generated by the rotation of the electric motor 2 even by a method using a rotary encoder.

  According to this modification, compared to the configurations shown in FIGS. 6 and 8, the generation of the 6th harmonic signal based on the motor rotation signal can be performed by a relatively simple control / configuration, so that the cost can be reduced. You can go down. In addition, since this modification can also use an existing rotary encoder in a hybrid vehicle, it is advantageous from this point of view as well.

(Modification 2)
Another modification of the vibration reduction device 1 of the present embodiment will be described with reference to FIG. The vibration reduction device 1B according to this modification includes a configuration that generates vibration using a speaker as a vibration generation unit that generates vibration having a phase opposite to that of the regenerative sound. For this reason, as shown in FIG. 12, the vibration reducing device 1 </ b> B includes a speaker 17 and a speaker control circuit 16 that controls the speaker 17 as a vibration generating unit that generates vibration having an opposite phase to the regenerative sound.

  The speaker control circuit 16 generates and outputs a control signal for driving the speaker 17 based on the antiphase signal generated by the fixed filter 5. The speaker control circuit 16 includes, for example, a circuit configuration such as an amplifier that amplifies a signal (antiphase signal) input from the fixed filter 5 and has a function as a power amplifier. The speaker 17 generates a sound wave having a phase opposite to that of the sixth harmonic signal S3 as vibration corresponding to the signal input from the speaker control circuit 16.

  The sound wave obtained in this way becomes a sound having a phase opposite to that of the regenerative sound generated from the support member 2a using the electric motor 2 as a vibration source, and propagates toward the support member 2a through the air. As a result, as shown in FIG. 12, the regenerative sound generated by the vibration V1 (see arrow v1) of the support member 2a using the electric motor 2 as the vibration source is a reverse-phase sound V3 (see symbol v3) applied by the speaker 17. ). As a result, regenerative sound generated as vibration of the support member 2a of the electric motor 2 is reduced.

  As in this modification, it is also possible to reduce the regenerative sound by generating a sound having a phase opposite to that of the regenerative sound by a method using a speaker instead of the actuator. In addition, as the speaker 17 that emits a sound having a phase opposite to that of the regenerative sound, for example, an existing speaker provided in the vehicle in a hybrid vehicle is used, or a dedicated speaker is used separately.

  According to the vibration reduction devices 1, 1 </ b> A, and 1 </ b> B of the present embodiment including the above-described modifications, the motor 2 is used as a vibration source in a configuration in which regenerative braking is performed by operating the motor 2 as a generator and collecting electric power. In other words, it is possible to eliminate the influence of the disturbance vibration on the vibration to be obtained, that is, to stably generate a signal having an opposite phase corresponding to the vibration of the motor 2 as the vibration source without being influenced by the vibration source other than the motor 2. And regenerative sound can be reliably reduced.

  In particular, the 6th harmonic signal of the electric motor 2 used for generating vibrations having the opposite phase to the regenerative sound in the vibration reducing device of the present embodiment is a regenerative sound vibration source obtained by the current sensor 3 or the rotary encoder 41. Since it is based on a signal generated from the electric motor 2 itself, it is not affected by disturbance vibration such as vehicle vibration during traveling that occurs in an actual vehicle. For this reason, according to the vibration reduction device of the present embodiment, it is possible to stably generate vibration having a phase opposite to that of the regenerative sound without being affected by disturbance vibration as compared with the configuration having the vibration sensor as in the related art. Can do. Further, according to the vibration reduction device of the present embodiment, the vibration sensor as in the conventional technique is unnecessary, and the calculation by the adaptive filter having a complicated structure as compared with the fixed filter 5 or the like is not required. The configuration for reducing regenerative sound can be realized with a very simple configuration.

  Further, in the vibration reducing apparatus of the present embodiment, by adopting the magnetostrictive actuator 7 as an actuator for imparting vibrations in the opposite phase to the support member 2a that is a regenerative sound generator, for example, an automobile such as a hybrid vehicle. Even in a high-temperature environment or an environment with a lot of vibrations, the influence of the environment can be reduced, and vibrations can be generated stably. In this respect, for example, in the case of a ceramic actuator, it is difficult to obtain a stable operation in a high-temperature environment (for example, 100 ° C. or more) such as in an automobile, and it may be damaged by vibration of the vehicle. According to No. 7, since it is relatively strong against high temperature environments and vibrations, stable operation can be obtained even in an automobile. In addition, according to the magnetostrictive actuator 7, a large output can be obtained with a small electric power, so that vibration can be generated efficiently.

  Thus, in a vibration reducing device used in an environment such as an automobile where there is a lot of vibration, a magnetostrictive actuator is suitable as an actuator that applies vibration to the regenerative sound generating unit. However, the actuator is not limited to a magnetostrictive actuator, and for example, an electromagnetic actuator, a piezoelectric element actuator, a ceramic actuator, or the like is used as appropriate.

[Second Embodiment]
A second embodiment of the present invention will be described. In addition, about the content, structure, etc. which are common in 1st Embodiment, description is abbreviate | omitted suitably. The vibration reduction method according to the present embodiment is the vibration reduction method according to the first embodiment as described above, wherein the vibration generated from the regenerative sound generator (support member 2a) is detected by a vibration sensor such as a microphone or an acceleration sensor. Based on the detection signal, feedback control is performed when generating an antiphase vibration by an actuator or the like using an adaptive filter. Here, the adaptive filter is a filter having a function of changing system characteristics in accordance with a signal processing process.

  That is, the vibration reduction method of the present embodiment uses a vibration sensor that functions as an error microphone, and generates a control signal (excitation signal) to an actuator drive circuit or the like based on a 6th harmonic signal when generating an antiphase signal. An adaptive filter is adopted as a filter to be generated, and in the adaptive filter, filter coefficients are sequentially updated based on the detection signal of the vibration sensor, and an antiphase signal is generated based on the updated filter coefficients. This eliminates the effects of environmental noise in the situation where regenerative sound occurs, and regenerative sound that changes due to changes in the environment such as temperature and humidity, or the characteristics of the motor and the characteristics of the actuator to give vibration. In response to this change, vibrations having an opposite phase to be applied to the regenerative sound generator can be generated, and the regenerative sound can be more effectively reduced.

  The vibration reducing method of this embodiment will be specifically described. In the vibration reduction method of this embodiment, first, vibration of the regenerative sound generator is detected and a vibration signal is generated. The vibration of the regenerative sound generator is detected by a vibration sensor as an error microphone. The vibration sensor is provided at a position away from the regenerative sound generator to some extent, detects a vibration sound mainly emitted from the regenerative sound generator as an error signal, generates a vibration signal, and outputs it. That is, the vibration sound detected by the vibration sensor includes regenerative sound and noise other than regenerative sound. As the vibration sensor, for example, an acceleration sensor, a microphone, a piezoelectric element, or the like is used.

  Further, a signal having a frequency that matches the frequency of the sixth harmonic (the frequency six times the fundamental wave) is extracted from the vibration signal regarding the vibration of the regenerative sound generator detected by the vibration sensor. For example, a tracking filter is used to extract such a signal. The tracking filter is a bandpass filter that varies the frequency of a signal to be passed. That is, a signal is extracted by allowing only a signal having a frequency matching the frequency of the sixth harmonic among the vibration signal output from the vibration sensor to pass through the tracking filter. As the tracking filter, for example, an IIR (Infinite Impulse Response) type filter is used.

  Then, the 6th harmonic signal for generating the antiphase signal is controlled by the adaptive filter so that the signal having the frequency that matches the frequency of the 6th harmonic extracted by the tracking filter is minimized. That is, the extracted signal is input to the filter unit including the adaptive filter and reflected in the update (correction) of the filter coefficient so that the signal extracted from the vibration signal that is the detection signal by the vibration sensor is minimized, Feedback control is performed on the excitation signal generated by the adaptive filter, that is, the antiphase signal.

  As described above, according to the vibration reduction method of the present embodiment that generates the antiphase signal (vibration signal) by the adaptive filter using the detection signal from the vibration sensor, the sixth harmonic is detected with respect to the detection signal from the vibration sensor. By performing processing using a tracking filter that allows the same frequency to pass through, accurate error detection can be performed, and an antiphase signal can be stably generated with little influence from environmental noise. Thereby, it is possible to stably reduce the regenerative sound regardless of changes in the surrounding environment. Further, according to the vibration reduction method of the present embodiment, howling can be easily suppressed by adjusting the filter coefficient in feedback control using an adaptive filter.

  A simulation for muting the interior sound (regenerative sound) by the vibration reducing method of the present embodiment will be described. As shown in FIG. 13, this simulation measures the in-vehicle sound detected by the microphone 51 and the current of the electric motor (MG1) detected by the current sensor in the hybrid vehicle, and has been described above based on these actually measured waveforms. The signal processing using the tracking filter and the adaptive filter is performed.

  The current signal output from the current sensor is input to the sixth harmonic generation unit 52 using PLL control as described above. The 6th harmonic generation unit 52 generates a 6th harmonic signal based on the input current signal. The 6th harmonic signal generated by the 6th harmonic generation unit 52 is input to an adaptive filter unit 53 using an LMS adaptive algorithm. On the other hand, the detection signal of the vehicle interior sound by the microphone 51 is filtered by the tracking filter 54 set so as to pass a signal having the same frequency as the sixth harmonic of the current signal by the current sensor, and is input to the adaptive filter unit 53. The

  The adaptive filter unit 53 uses the 6th harmonic signal input from the 6th harmonic generation unit 52 as a reference signal, sequentially updates the filter coefficient based on the input signal from the tracking filter 54, and reverses the reference signal. Outputs a phase signal. In this way, the signal having the opposite phase output from the adaptive filter unit 53 is used as a signal for canceling the vehicle interior sound detected by the microphone 51. Such a muffler effect of the interior sound was simulated.

  FIG. 14 shows the result of this simulation. FIG. 14A is a graph showing an acoustic analysis result of in-vehicle sound based on detection data by the microphone 51. The horizontal axis of the graph is time, the vertical axis is frequency, and the background color (brightness) of the graph indicates power (acoustic power). FIG. 14A shows an acoustic analysis result of in-vehicle sound observed in the vehicle when the hybrid vehicle decelerates, as in the graph shown in FIG. Moreover, FIG.14 (b) is a graph which shows the acoustic analysis result at the time of giving the signal of the antiphase produced | generated by the structure as mentioned above with respect to the vehicle interior sound shown to the figure (a).

  In the graph shown in FIG. 14A, as indicated by the symbol K1, a mountain-like linear portion having a high power appears locally. This linear part represents the regenerative sound. On the other hand, in the graph shown in FIG. 14B, the linear portion representing the regenerative sound disappears in FIG. That is, according to the configuration adopting the vibration reducing method of the present embodiment as shown in FIG. 13, the signal in the reverse phase for canceling the regenerative sound is a linear portion representing the regenerative sound shown in FIG. In other words, the frequency is changed in the same manner as the regenerative sound so as to follow the change in the frequency of the regenerative sound over time. From the simulation results as described above, it has been confirmed that the vibration reduction method of the present embodiment is very effective in reducing regenerative sound in the vehicle interior sound.

  As an example of a device configuration for performing the vibration reduction method of the present embodiment as described above, a vibration reduction device according to the present embodiment will be described.

  As shown in FIG. 15, the vibration reduction device 61 according to the present embodiment further includes a vibration sensor 62, a tracking filter 63, and a period detection unit 64 in the configuration provided in the vibration reduction device 1 of the first embodiment. Instead of the fixed filter 5, an LMS adaptive filter unit 65 having an FIR (Finite Impulse Response) filter 66 is provided.

  The vibration sensor 62 is configured as a vibration detection unit that detects the vibration of the regenerative sound generation unit, and functions as an error microphone. The vibration sensor 62 is provided at a position away from the support member 2a, which is a regenerative sound generator, to a certain extent, and detects a vibration sound mainly emitted from the support member 2a as an error signal to generate and output a vibration signal. Here, the regenerative sound generator that generates the vibration detected by the vibration sensor 62 includes part of the electric motor 2. The vibration sound detected by the vibration sensor 62 includes regenerative sound and noise other than the regenerative sound. As the vibration sensor 62, for example, an acceleration sensor, a microphone, a piezoelectric element, or the like is used.

  The vibration signal output from the vibration sensor 62 is input to the tracking filter 63. Specifically, the vibration signal of the vibration sensor 62 is input to the tracking filter 63 as a digital signal via an amplifier and an A / D converter.

  The tracking filter 63 passes only a signal having a frequency matching the frequency of the sixth harmonic among the vibration signals input from the vibration sensor 62. That is, the tracking filter 63 functions as a signal extraction unit that extracts a signal having a frequency that is a predetermined number of times higher than the vibration signal generated by the vibration sensor 62 and a frequency that matches the frequency that is six times the fundamental wave in this embodiment. To do. As the tracking filter 63, for example, a secondary IIR type filter is used.

  The period detection unit 64 receives the 6th harmonic signal S3 generated by the harmonic generation unit 4, detects the period of the 6th harmonic signal S3, and outputs a signal corresponding to the period. The period detector 64 converts, for example, the sixth harmonic signal S3 into a rectangular wave signal, and measures the time between zero-cross points of the rectangular wave signal, that is, the pulse width (one period of time) in the rectangular wave signal. Thus, the period of the 6th harmonic signal S3 is detected. For this reason, the period detection unit 64 has a function of generating a rectangular wave signal and is configured as a circuit including a counter and a detection circuit for measuring a zero cross point.

  The signal output from the period detection unit 64 is input to the tracking filter 63 and is used for setting a frequency for allowing the signal to pass through the tracking filter 63. That is, the tracking filter 63 sets the frequency of the 6th harmonic signal S3 as a specific frequency to pass based on the signal corresponding to the period of the 6th harmonic signal S3 input from the period detection unit 64.

  The LMS adaptive filter unit 65 functions as an antiphase signal generation unit that generates an antiphase signal having a phase opposite to that of the sixth harmonic signal S3 generated by the harmonic generation unit 4. Specifically, the LMS adaptive filter unit 65 is generated by the harmonic generation unit 4 so that a signal having a frequency that matches the frequency of the sixth harmonic signal S3 extracted by the tracking filter 63 is minimized. The sixth harmonic signal S3 is controlled by the FIR filter 66. The LMS adaptive filter unit 65 operates in response to the input of the sixth harmonic signal S3 generated by the harmonic generation unit 4 and controls the actuator drive circuit 6.

  As shown in FIG. 15, the LMS adaptive filter unit 65 changes the filter coefficient of the FIR filter 66 incorporated in the LMS adaptive filter using the LMS algorithm. That is, the error signal generated at a certain timing in the LMS adaptive filter unit 65 is generated by the filter coefficient at that timing, and the LMS adaptive filter unit 65 does not increase the error among the filter coefficients. By changing the value of the filter coefficient slightly in the direction of decreasing, and by changing the value of the filter coefficient slightly in the direction of increasing for those that reduce the error, it is optimal in terms of time average. Get the filter coefficients.

  The LMS adaptive filter unit 65 includes an FIR filter 66 and a coefficient correction unit 67 that corrects the filter coefficient. The LMS adaptive filter unit 65 receives the frequency component signal of the 6th harmonic frequency output from the tracking filter 63 in the coefficient correction unit 67, and receives the filter coefficient of the FIR filter 66 based on a predetermined convergence constant. Update. Thereby, the antiphase signal output from the FIR filter 66 is adjusted.

  FIG. 16 is a diagram illustrating the basic function of the LMS adaptive filter unit 65. As shown in FIGS. 15 and 16, the LMS adaptive filter unit 65 having the FIR filter 66 receives the 6th harmonic signal S3 generated by the harmonic generation unit 4 as an input signal, that is, a reference signal x (n The filter coefficient is updated using the reference signal and the error signal. The error signal e (n) is, for example, a mean square error, and a response (Response) d (n) which is a vibration signal based on the vibration of the electric motor 2 detected by the vibration sensor 62 and the FIR. An output (Response) y (n) by the actuator 7 based on the output signal of the filter 66 (filter coefficient H (n)) is a synthesized signal. Here, the response d (n) corresponds to the vibration V1 (see arrow v1) of the support member 2a using the electric motor 2 as a vibration source, and the output y (n) is an antiphase vibration V2 applied by the actuator 7. (Refer to arrow v2). The LMS adaptive filter unit 65 operates so as to always reduce the error signal e (n).

  The LMS adaptive filter unit 65 passes the reference signal x (n), which is a reference signal, through the FIR filter 66 defined by the filter coefficient H (n). Based on the output signal from the FIR filter 66, the actuator drive circuit 6 and the actuator 7 generate vibration V2 having an opposite phase. The LMS adaptive filter unit 65 combines the vibration V1 (d (n)) of the support member 2a using the electric motor 2 as a vibration source and the vibration V2 (y (n)) of the opposite phase as an error signal e ( n), that is, the filter coefficient H (n) of the FIR filter 66 is automatically adjusted (updated) so that the output of the vibration sensor 62 becomes “0”. When the error signal e (n) becomes “0”, the vibration V1 of the support member 2a and the vibration V2 having the opposite phase are equal to each other and have the opposite phase relationship.

  The LMS adaptive filter unit 65 is a filter that does not have a fixed function and changes so as to be always optimal (error = 0). That is, as described above, regarding the LMS adaptive filter unit 65 obtaining a filter coefficient that is optimal in terms of time average, “optimal” means an operation that minimizes the cost function defined by the root mean square of the signal to be deleted. This physically corresponds to minimizing the power of the error signal. Note that the specific contents of the calculation formula and the like relating to the optimization in the time domain by the LMS adaptive filter unit 65, that is, the method for calculating the only minimum value (optimum value) of the cost function, are well known and will not be described. .

According to the configuration shown in FIG. 16, a specific coefficient update formula of the inverse function in the LMS adaptive filter unit 65 is as the following formula (1).
H (n + 1) = H (n) −αx (n) e (n) (1)

  In the above equation (1), H (n) represents the filter coefficient of the FIR filter 66, x (n) is an input signal (reference signal), e (n) is an error signal, and n is the number of filter taps. And α is a convergence coefficient.

Based on the above equation (1), a specific example of the coefficient updating equation in the LMS adaptive filter unit 65 having the above-described configuration is shown in the following equation (2).
Hk [n + 1] = hk [n] +2 μe [n] · x [n−k], k = 0, 1,... M (2)

  In the above equation (2), k represents a sample time, h is a state variable, μ is a convergence constant, and M is an order.

FIG. 17 is a block diagram illustrating an example of a configuration for updating the coefficients of the adaptive filter according to the present embodiment. The configuration shown in FIG. 17 is for the case where the order M = 2 in the above equation (2). In this figure, the solid line represents the signal to be filtered, and the broken line represents the coefficient update signal. In FIG. 17, Z ⁻¹ represents a delay element.

  The anti-phase signal that is the output signal from the LMS adaptive filter unit 65 configured as described above is optimized based on the signal from the vibration sensor 62. The output signal from the LMS adaptive filter unit 65 is a digital signal, which is input to the actuator drive circuit 6 and used for drive control of the actuator 7 after being subjected to D / A conversion processing by DAC, modulation processing by PWM, and the like. It is done.

  According to the vibration reduction device 61 of the present embodiment having the above-described configuration, since the processing by the tracking filter 63 that passes the same frequency as the sixth harmonic is performed on the signal of the vibration sensor 62, it is accurate. Error detection is possible, and an antiphase signal can be stably generated without being substantially affected by environmental noise. Thereby, it is possible to stably reduce the regenerative sound regardless of changes in the surrounding environment. Further, according to the vibration reducing apparatus 61 of the present embodiment, howling can be easily suppressed by adjusting the filter coefficient in the feedback control using the adaptive filter.

  In addition, although the vibration reduction apparatus 61 of this embodiment employ | adopts the LMS type | mold adaptive filter which used the LSM algorithm as an adaptive filter, as an adaptive filter, it is not limited to a LMS type | mold, For example, RLS An adaptive filter that employs another well-known algorithm such as the (Recursive Least Square) algorithm may be employed. Also in the vibration reducing apparatus 61 of the present embodiment, a modification of the vibration reducing apparatus 1 of the first embodiment as described above, that is, a configuration using a rotary encoder when generating a 6th harmonic signal, an actuator instead of A configuration using a speaker may be combined as appropriate.

[Third Embodiment]
A third embodiment of the present invention will be described. The present embodiment shows an example of a hybrid vehicle including the vibration reducing device described in the above-described embodiment. That is, the present embodiment is an example when the above-described vibration reduction device is applied to a hybrid vehicle.

  As shown in FIG. 18, a hybrid vehicle 71 according to the present embodiment is a hybrid vehicle including the above-described vibration reducing device, and is connected to the engine 72 and the engine 72 and is used mainly for power generation. A generator (MG1, hereinafter referred to as “power generation MG”) 96 and a driving motor generator (MG2, hereinafter referred to as “driving MG”) connected to the engine 72 and used mainly for obtaining the driving force of the axle 73. And 97).

  The engine 72 is an internal combustion engine that uses gasoline, light oil, or the like as fuel. The engine 72 has a crankshaft 72b as an output shaft that rotates by linear reciprocation of a piston 72a due to combustion of fuel in a cylinder (not shown). The engine 72 is controlled by an engine electronic control unit (ENGECU) 74 included in the hybrid vehicle 71. The engine 72 is provided with an engine rotation sensor 72c that detects the rotation of the crankshaft 72b of the engine 72.

  The rotational driving force of the crankshaft 72b is distributed and integrated by a power distribution and integration mechanism 75 configured as a planetary gear mechanism. The power distribution and integration mechanism 75 includes a carrier 75a connected to the crankshaft 72b, a plurality of pinion gears 75b rotatably provided on the carrier 75a, and a plurality of pinion gears 75b provided on the inner peripheral side of the plurality of pinion gears 75b. A sun gear 75c that meshes with each other and a ring gear 75d that is provided on the outer peripheral side of the plurality of pinion gears 75b and meshes with the plurality of pinion gears 75b.

  A ring gear shaft 76 disposed coaxially with the crankshaft 72b extends from the ring gear 75d of the power distribution and integration mechanism 75. The rotation of the ring gear 75d is transmitted to the differential 78 through a gear mechanism 77 including a gear meshing with the outer peripheral side of the ring gear 75d, and is transmitted from the differential 78 to the axle 73 to which the driving wheel 73a is connected.

  Each of the power generation MG 96 and the drive MG 97 has a three-phase (U phase, V phase, W phase) AC synchronous configuration, and employs PWM control as a drive control method. All of these motor generators are arranged coaxially with the crankshaft 72 b of the engine 72, and the power generation MG 96 is arranged on the side closer to the engine 72, and the driving MG 97 is arranged on the side far from the engine 72.

  Each of the power generation MG 96 and the drive MG 97 includes a rotor (rotor) 79a that rotates coaxially with the crankshaft 72b, and a stator (stator) 79b in which a three-pole coil (electromagnet) is disposed around the rotor 79a. Have. The rotor 79a of the power generation MG 96 is connected to the sun gear 75c of the power distribution and integration mechanism 75. Further, the rotor 79a of the drive MG 97 is coupled to the ring gear shaft 76. Each motor generator changes the pole of the stator 79b by receiving an alternating current, and rotates by repeatedly attracting and repelling the coil of the stator 79b and the permanent magnet provided around the rotor 78a.

  Inverters 81 and 82 for controlling electric power of each motor generator are connected to power generation MG 96 and drive MG 97, respectively. These inverters 81 and 82 are connected to each other by a power line 80. The power generation MG 96 and the drive MG 97 are controlled by a motor electronic control unit (MGECU) 83 provided in the hybrid vehicle 71. The motor electronic control unit 83 controls the drive of the two motor generators by controlling the inverters 81 and 82. The power generation MG 96 is provided with a current sensor 84a for detecting the current of the power generation MG 96 and two rotation sensors 84b for detecting the rotation of the power generation MG 96. Similarly, the driving MG 97 is provided with a current sensor 85 a for detecting the current of the driving MG 97 and two rotation sensors 85 b for detecting the rotation of the driving MG 97.

  Thus, in hybrid vehicle 71, motor unit 86 including power distribution and integration mechanism 75, power generation MG 96, drive MG 97, and inverters 81 and 82 is configured to receive rotation of crankshaft 72 b with respect to engine 72. Is provided. Hybrid vehicle 71 also includes a battery 87 that transmits and receives power to and from power generation MG 96 and drive MG 97 via inverters 81 and 82. The battery 87 is configured as, for example, a lithium ion secondary battery or a nickel hydride rechargeable battery.

  The hybrid vehicle 71 includes a hybrid electronic control unit (HVECU) 88 that controls the entire vehicle. The hybrid electronic control unit 88 communicates with the engine electronic control unit 74 and the motor electronic control unit 83, and controls the engine 72, the power generation MG 96 and the drive MG 97 via these electronic control units, so that the vehicle To control the overall operation of. As described above, each electronic control unit included in the hybrid vehicle 71 is configured as a microprocessor centered on a CPU. In addition to the CPU, a ROM that stores a processing program and a RAM that temporarily stores data. And an input / output port and a communication port.

  The hybrid vehicle 71 having the above-described configuration is propelled by driving the driving wheel 73a by operating the engine 72 and the driving motor MG97 of the two motor generators mainly as a driving source during vehicle propulsion. On the other hand, when the vehicle decelerates, the power generation MG 96 of the two motor generators is mainly operated as a generator, and mechanical power transmitted from the drive wheels 73a to the power generation MG 96 is converted into electric power, that is, kinetic energy. Is converted into electric energy, so that braking force is generated in the drive wheels 73a to decelerate the vehicle, and so-called regenerative braking (regenerative braking) is performed in which the converted electric power (electric energy) is recovered in the battery 87. The driving force of the drive wheels 73a when the hybrid vehicle 71 is propelled or the like is mainly obtained by the driving MG 97, but can also be appropriately obtained by the power generating MG 96. Further, in the hybrid vehicle 71, the power recovery by the motor generator is mainly performed by the power generation MG 96, but the power recovery by the driving MG 97 is also appropriately performed.

  And in the hybrid vehicle 71 of this embodiment, MG96 for electric power generation is an electric motor in the vibration reduction apparatus of embodiment mentioned above. That is, the power generation MG 96 is an electric motor that is a vibration source that generates regenerative sound during regenerative braking performed when the hybrid vehicle 71 is decelerated as described above.

  Therefore, the hybrid vehicle 71 of the present embodiment has a configuration for reducing regenerative sound, a current sensor 84a that detects the current signal of the power generation MG 96 in real time, a regenerative sound control unit 91, a vibration sensor 92, and vibration. And an actuator 93.

  The current sensor 84a has a configuration corresponding to the current sensor 3 in the vibration reducing device described above. That is, the current sensor 84a functions as a rotation detection unit that detects a current signal as a rotation signal generated by the rotation of the power generation MG 96.

  The regenerative sound control unit 91 has a configuration (functional unit) corresponding to each of the harmonic generation unit 4 and the LMS adaptive filter unit 65 in the vibration reduction device described above. That is, the regenerative sound control unit 91 is based on a rotation signal (current signal) of the power generation MG 96 detected by the current sensor 84a, and determines a predetermined frequency among harmonics having a frequency that is an integral multiple of the fundamental wave of this signal. It functions as a harmonic generation unit that generates a sixth harmonic signal (sixth harmonic signal) that is a harmonic of a multiple frequency. In addition, the regenerative sound control unit 91 functions as an antiphase signal generation unit that generates an antiphase signal having a phase opposite to that of the sixth harmonic signal generated by the harmonic generation unit. Therefore, the function part as an antiphase signal generation part which regenerative sound control part 91 has has each function part equivalent to each of FIR filter 66 and coefficient correction part 67 in the vibration reducing device mentioned above. A current signal from the current sensor 84a is input to a functional unit serving as a harmonic generation unit included in the regenerative sound control unit 91.

  The vibration sensor 92 has a configuration corresponding to the vibration sensor 62 in the vibration reducing device described above. That is, the vibration sensor 92 functions as a vibration detection unit that detects a vibration of a regenerative sound generation unit such as a portion that supports the power generation MG 96 and generates a vibration signal. The vibration sensor 92 is, for example, an acceleration sensor, a microphone, a piezoelectric element, or the like. A detection signal (vibration signal) from the vibration sensor 92 is input to the regenerative sound control unit 91. For this reason, the regenerative sound control unit 91 has a configuration (functional unit) corresponding to each of the tracking filter 63 and the period detection unit 64 in the vibration reducing device described above in addition to the functional unit described above.

  That is, the regenerative sound control unit 91 uses a vibration signal of vibration of the regenerative sound generation unit detected by the vibration sensor 92 to a predetermined number of times, in the case of the present embodiment, a 6th harmonic frequency (6 times the fundamental wave). It functions as a signal extraction unit that extracts a signal having a frequency that matches the frequency of the signal. In addition, the regenerative sound control unit 91 functions as a cycle detection unit that receives an input of the 6th harmonic signal generated by the harmonic generation unit and detects the cycle of the 6th harmonic signal. The regenerative sound control unit 91 controls the 6th harmonic signal so that the extracted 6th harmonic frequency signal is minimized.

  The vibration actuator 93 has a configuration corresponding to each of the actuator drive circuit 6 and the actuator 7 in the vibration reduction device described above, and functions as a vibration generation unit. That is, the vibration actuator 93 has a circuit configuration for driving and controlling the actuator based on the reverse phase signal generated by the functional unit as the reverse phase signal generation unit of the regenerative sound control unit 91. Moreover, the vibration actuator 93 has an actuator that vibrates while being in contact with the regenerative sound generator. The vibration actuator 93 is provided so that the vibration of the actuator is transmitted to the regenerative sound generator. Therefore, the vibration actuator 93 is provided such that the portion of the actuator is in contact with a portion that supports the power generation MG 96, which is a regenerative sound generator. As the vibration actuator 93, a configuration including a magnetostrictive actuator that can obtain a stable operation even in a high-temperature environment or a vibrating environment such as in an automobile as described above is preferably used. However, the actuator included in the vibration actuator 93 may be an electromagnetic actuator, a piezoelectric element actuator, a ceramic actuator, or the like.

  As described above, the hybrid vehicle 71 of the present embodiment includes the current sensor 84a that detects the current signal of the power generation MG 96 in real time, the regenerative sound control unit 91, the vibration sensor 92, and the vibration actuator 93. Is provided as a vibration reducing device for reducing regenerative sound generated during regenerative braking of the hybrid vehicle 71. That is, in the hybrid vehicle 71 of the present embodiment, the regenerative sound control unit 91 generates a 6th harmonic signal based on the current signal of the power generation MG 96 detected by the current sensor 84a, and the 6th harmonic signal Generation of an antiphase signal having an opposite phase is performed. Further, in the regenerative sound control unit 91, extraction of a signal having a frequency matching the frequency of the sixth harmonic from the vibration signal of the vibration sensor 92 and feedback control of the sixth harmonic signal by an adaptive filter are performed. Then, the vibration actuator 93 generates a vibration having a phase opposite to that of the regenerative sound based on the reverse phase signal generated by the regenerative sound control unit 91, and the regenerative sound is canceled and reduced by the vibration having the reverse phase.

  According to the hybrid vehicle 71 of the present embodiment as described above, in a configuration in which regenerative braking is performed in which the power generation MG 96 is operated as a power generator and power is collected in the battery 87, the vibration generated using the power generation MG 96 as a vibration source. It is possible to eliminate the influence of disturbance vibration, stably generate an antiphase signal corresponding to the vibration of the vibration source, and reliably reduce regenerative sound.

  In the above description, the hybrid vehicle 71 is configured to perform feedback control using an adaptive filter based on a detection signal from the vibration sensor 92 as a configuration for reducing regenerative sound, that is, the above-described second embodiment. Although the structure corresponding to the vibration reduction apparatus 61 of this invention is provided, you may provide the structure corresponding to the vibration reduction apparatus 1 of 1st Embodiment mentioned above. In this case, the signal of the vibration sensor 92 is not used in the regenerative sound control unit 91, and instead of the configuration corresponding to the LMS adaptive filter unit 65 in the regenerative sound control unit 91, it corresponds to the fixed filter 5 included in the above-described vibration reduction device. In addition, the regenerative sound control unit 91 does not require a configuration corresponding to each of the tracking filter 63 and the period detection unit 64 in the vibration reduction device described above. According to such a configuration, the vibration sensor 92 is not required, and computation by an adaptive filter having a relatively complicated structure is not required. Therefore, the configuration for reducing regenerative sound can be made with a very simple configuration. It can be realized. Moreover, in the vibration reduction apparatus with which the hybrid vehicle 71 is provided, the various modifications mentioned in the vibration reduction apparatus mentioned above can be employ | adopted suitably.

  Further, in the present embodiment, the example in which the above-described vibration reduction device is applied to a hybrid vehicle including two motor generators for power generation and driving has been described. However, the vibration reduction device and the vibration reduction method according to the present invention are described. Can be widely applied in apparatus configurations in which regenerative sound is generated using the motor as a vibration source by regenerative braking in which the motor is operated as a generator to collect electric power. Therefore, the vibration reduction method and the vibration reduction device according to the present invention are not limited to the hybrid vehicle including the two motor generators for generating power and driving as described above, and may be applied to a configuration including one electric motor. Can do. The vibration reducing method and the vibration reducing apparatus according to the present invention can be widely applied to, for example, electric vehicles, ships, household electric appliances (for example, washing machines and vacuum cleaners) in addition to hybrid vehicles. .

DESCRIPTION OF SYMBOLS 1 Vibration reduction apparatus 2 Electric motor 2a Support member (vibration part)
3 Current sensor (rotation detector)
4 Harmonic generator 5 Fixed filter (antiphase signal generator)
6 Actuator Drive Circuit 7 Actuator 16 Speaker Control Circuit 17 Speaker 41 Rotary Encoder (Rotation Detection Unit)
61 Vibration reduction device 62 Vibration sensor (vibration detector)
63 Tracking filter (signal extraction unit)
65 LMS adaptive filter unit (antiphase signal generation unit)
66 FIR filter 67 Coefficient correction unit 71 Hybrid vehicle 72 Engine 84a Current sensor (rotation detection unit)
91 Regenerative sound controller (harmonic generator, antiphase signal generator, signal extractor)
92 Vibration sensor (vibration detector)
93 Vibration actuator (vibration generator)
96 Motor generator for power generation 97 Motor generator for driving

Claims (6)

A vibration reduction method for reducing regenerative sound generated by regenerative braking in which an electric motor is operated as a generator to collect electric power,
Detecting a rotation signal generated by rotation of the electric motor;
Based on the rotation signal, among the harmonics having a frequency that is an integral multiple of the fundamental wave of the rotation signal, a harmonic signal of a harmonic having a predetermined number of times a predetermined frequency is generated,
Generating an antiphase signal having a phase opposite to that of the harmonic signal;
Based on the anti-phase signal, generate a vibration having an anti-phase with the regenerative sound,
The vibration reduction method, wherein the regenerative sound is canceled and reduced by the vibrations having the opposite phase. Detecting a vibration of a vibration part that generates the regenerative sound to generate a vibration signal;
From the vibration signal, extract a signal having a frequency matching the predetermined number of times,
The vibration reduction method according to claim 1, wherein the harmonic signal is controlled by an adaptive filter so that the extracted signal of the frequency is minimized. A vibration reducing device that reduces regenerative sound generated by regenerative braking that operates an electric motor as a generator to collect electric power,
A rotation detector that detects a rotation signal generated by rotation of the electric motor;
Based on the rotation signal, among the harmonics having a frequency that is an integral multiple of the fundamental wave of the rotation signal, a harmonic generation unit that generates a harmonic signal of a harmonic having a predetermined number of times a predetermined frequency,
An anti-phase signal generator that generates an anti-phase signal having a phase opposite to that of the harmonic signal;
A vibration generation unit that generates vibrations in reverse phase with the regenerative sound based on the reverse phase signal;
The vibration reducing apparatus, wherein the regenerative sound is canceled and reduced by the vibration of the opposite phase. A vibration detection unit that detects vibration of the vibration unit that generates the regenerative sound and generates a vibration signal;
A signal extraction unit that extracts a signal having a frequency that matches the predetermined multiple of the frequency from the vibration signal;
The vibration reduction according to claim 3, wherein the antiphase signal generation unit controls the harmonic signal with an adaptive filter so that the signal of the frequency extracted by the signal extraction unit is minimized. apparatus. The vibration generator is
A magnetostrictive actuator that vibrates in contact with the vibration part that generates the regenerative sound; and
The vibration reduction device according to claim 3, further comprising: an actuator drive circuit that drives the magnetostrictive actuator based on the antiphase signal. A hybrid vehicle comprising the vibration reducing device according to any one of claims 3 to 5,
An engine,
A motor generator for power generation connected to the engine and mainly used for power generation;
A drive motor generator connected to the engine and used mainly for obtaining the driving force of the axle,
The hybrid vehicle, wherein the power generation motor generator is the electric motor.