Motor behavior sound generator

Abstract

To provide a technique capable of generating sounds that change according to behavior of an electric motor.SOLUTION: A motor behavior sound generator includes: a sound source signal generation unit that generates a sound source signal corresponding to changes in a coil voltage or a coil current of an electric motor; and a signal adjustment unit that generates an acoustic signal suitable for input to a speaker by applying signal adjustment processing including signal amplification to the sound source signal.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a motor motion sound generating device. [Background technology]

[0002] In electric vehicles and hybrid vehicles, the lack of internal combustion engine noise when running in EV mode using an electric motor makes it difficult for drivers and pedestrians to understand the vehicle's operating state. For this reason, attempts have been made to generate simulated engine noise when the vehicle is running in EV mode.

[0003] Patent Document 1 discloses an in-vehicle device that generates a pseudo-engine sound of a vehicle. This in-vehicle device is configured to emit a pseudo-engine sound that imitates the operating sound of an internal combustion engine when the running noise inside the vehicle cabin during a drive mode using an electric motor as a power source is below a predetermined level. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2023-068410 Summary of the Invention [Problem to be solved by the invention]

[0005] To generate a sound that corresponds to the vehicle's EV driving state, it is desirable to change the sound according to the behavior of the electric motor. However, the above-mentioned conventional technology does not take into consideration changing the sound according to the behavior of the electric motor. Therefore, a technology that can generate a sound that changes according to the behavior of the electric motor is desired. This problem is also common to electric motors used in devices other than vehicles. [Means for solving the problem]

[0006] The present disclosure has been made to solve at least part of the above-mentioned problems, and can be realized in the following forms.

[0007] According to one aspect of the present disclosure, there is provided a motor behavior sound generating device including: a sound source signal generating unit that generates a sound source signal in response to a change in a coil voltage or a coil current of an electric motor; and a signal adjusting unit that applies signal adjusting processing, including signal amplification, to the sound source signal to generate an acoustic signal suitable for input to a speaker. This motor behavior sound generating device generates an acoustic signal in response to changes in the coil voltage or coil current of the electric motor, making it possible to generate a sound that changes in response to the behavior of the electric motor. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a block diagram showing the configuration of a motor behavior sound generation device according to a first embodiment. [Figure 2] FIG. 2 is a circuit diagram showing an example of a circuit constituting the motor motion sound generating device. [Figure 3] FIG. 4 is a diagram showing an example of an output signal of each circuit. [Figure 4] Graph showing the results of frequency analysis of coil voltage and coil current. [Figure 5] FIG. 10 is a block diagram showing the configuration of a motor behavior sound generation device according to a second embodiment. [Figure 6] FIG. 10 is a block diagram showing the configuration of a motor behavior sound generation device according to a third embodiment. [Figure 7] FIG. 10 is a block diagram showing the configuration of a motor behavior sound generation device according to a fourth embodiment. [Figure 8] FIG. 10 is a block diagram showing the configuration of a motor behavior sound generation device according to a fifth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] 1 is a block diagram showing the configuration of a motor behavior sound generation device 200a in the first embodiment. The electric motor 100 includes an electromagnetic coil 110 and a drive circuit 120. The electromagnetic coil 110 is connected to the drive circuit 120 via connection wiring 130. The drive circuit 120 includes an H-bridge circuit made up of four transistors 121 to 124 that drives the electromagnetic coil 110. The electromagnetic coil 110 is driven according to PWM control.

[0010] The electric motor 100 shown in FIG. 1 has a configuration for one phase. A two-phase motor has electromagnetic coils 110 for two phases and an H-bridge circuit. A three-phase motor has electromagnetic coils 110 for three phases and an H-bridge circuit. The present disclosure is applicable to electric motors 100 with any number of phases.

[0011] The motor behavior sound generation device 200a of the first embodiment includes a sound source signal generation unit 210 that generates a sound source signal Sc1 corresponding to a change in the coil voltage of the electric motor 100, a signal adjustment unit 220 that applies signal adjustment processing including signal amplification to the sound source signal Sc1 to generate an acoustic signal Sa suitable for input to the speaker 230, and a speaker 230. However, the speaker 230 may be configured as an external device, excluded from the motor behavior sound generation device 200a.

[0012] The sound source signal generating unit 210 includes an attenuator 211 that receives the voltage across the electromagnetic coil 110 as input and outputs a sound source signal Sc1. A line voltage may be used instead of the voltage across the electromagnetic coil 110. In the present disclosure, the term "coil voltage" encompasses both the voltage across the electromagnetic coil and the line voltage. The attenuator 211 has a function of attenuating an input signal to generate an output signal. The attenuator 211 is used to adjust the voltage across the electromagnetic coil 110 to a voltage suitable for the input of the signal adjusting unit 220. For example, the driving voltage of a vehicle motor is high, ranging from 60 V to 600 V, while the voltage of an audio amplifier is approximately 0.1 Vpp to 2 Vpp (voltage peak to peak). Therefore, it is preferable to use the attenuator 211 to reduce the voltage. However, when the voltage across the electromagnetic coil 110 is not so high, such as in the case of a driving motor used in a one- or two-person mobility vehicle or an electrically assisted vehicle, the attenuator 211 can be omitted. In addition, when a sound source is required by legal regulations, the attenuator 211 and the signal adjustment unit 220 can be omitted, and both ends of the coil of the speaker 230 can be connected in parallel to the electromagnetic coil 110 to generate sound.

[0013] The signal adjustment unit 220 includes an offset unit 221 that offsets the signal level of the sound source signal Sc1, and an amplifier 222 that amplifies the output of the offset unit 221 to generate an audio signal Sa. When the audio signal Sa is input to a speaker 230, the speaker 230 generates a sound that corresponds to the behavior of the electric motor 100. The volume of the speaker 230 can be changed by a volume adjustment signal VOL that is input to the amplifier 222 in response to a volume operation by the user. It is also possible to determine the operating environment using AI technology and automatically change the volume adjustment signal VOL to adapt to the environment.

[0014] 2 is a circuit diagram showing an example of a circuit constituting the motor behavior sound generation device 200a. Here, the circuit configuration of an attenuator 211, an offset unit 221, and an amplifier 222 is shown. The attenuator 211 is configured as an attenuation circuit combining a capacitor and a resistor. The offset unit 221 is configured as a voltage divider circuit using a variable resistor.

[0015] The amplifier 222 includes an automatic gain controller 222a (AGC) and an audio amplifier 222b. As the audio amplifier 222b, it is preferable to use a BTL (Balanced Transformer Less) compatible class D amplifier using an H-bridge circuit that has excellent wideband frequency characteristics.

[0016] FIG. 3 is a conceptual diagram showing an example of the output signals of each circuit. Illustrated here are the voltage across the electromagnetic coil 110, the output of the attenuator 211, the output of the offset unit 221, and the output of the AGC 222a. In reality, the voltage across the electromagnetic coil 110 has a larger voltage range, but for convenience of illustration, FIG. 3 depicts it with a small voltage range. The attenuator 211 reduces the voltage range of the voltage across the electromagnetic coil 110 to an appropriate value. The offset unit 221 offsets the input signal to adjust it to a signal level appropriate for an audio signal. However, the offset unit 221 may be omitted.

[0017] FIG. 4 is a graph showing the results of frequency analysis of the coil voltage and coil current. These graphs show the intensity of third-order and higher harmonics as a percentage, with the intensity of the first-order fundamental wave being 100%. The period of the first-order fundamental wave corresponds to one period of PWM control. As can be seen from these graphs, the coil voltage and coil current contain not only the first-order fundamental wave but also various third-order and higher harmonics. Therefore, if an audio signal Sa is generated in response to the coil voltage or coil current, it is possible to generate natural sound that corresponds to the unique behavior of the electric motor 100.

[0018] As described above, in the first embodiment, the acoustic signal Sa is generated from changes in the coil voltage of the electric motor 100, so that a sound that changes in accordance with the behavior of the electric motor 100 can be generated.

[0019] 5 is a block diagram showing the configuration of a motor behavior sound generation device 200b in the second embodiment. The second embodiment differs from the first embodiment only in the internal configuration of the sound source signal generation unit 210, and the other configurations are the same as those in the first embodiment.

[0020] The sound source signal generating unit 210 of the second embodiment includes an analog Hall IC 212 that generates a sound source signal Sc2 in response to a change in the coil current. The analog Hall IC 212 is arranged in a non-contact manner near the connection wiring 130 that connects the electromagnetic coil 110 to the drive circuit 120. The analog Hall IC 212 outputs an analog signal in response to the strength of the magnetic field. When the coil current of the electromagnetic coil 110 changes, the strength of the magnetic field around the connection wiring 130 changes. Therefore, the analog Hall IC 212 can generate a sound source signal Sc2 in response to a change in the coil current.

[0021] The motor behavior sound generating device 200b of the second embodiment can generate a sound that changes according to the behavior of the electric motor 100 by utilizing changes in the coil current.

[0022] 6 is a block diagram showing the configuration of a motor behavior sound generation device 200c in the third embodiment. The third embodiment differs from the first embodiment only in the internal configuration of the sound source signal generation unit 210, and the other configurations are the same as those in the first embodiment.

[0023] The sound source signal generating unit 210 of the third embodiment includes a pickup coil 213 and a pre-amplifier 214. The pickup coil 213 is disposed near the connection wiring 130 that connects the electromagnetic coil 110 to the drive circuit 120 in a non-contact manner. When the coil current of the electromagnetic coil 110 changes, the strength of the magnetic field around the connection wiring 130 changes. Therefore, the pickup coil 213 can generate a signal corresponding to the change in the coil current. The pre-amplifier 214 amplifies the output signal of the pickup coil 213 to generate a sound source signal Sc3 at a level suitable for input to the signal adjusting unit 220. However, the pre-amplifier 214 may be omitted.

[0024] According to the motor behavior sound generating device 200c of the third embodiment, it is possible to generate a sound that changes according to the behavior of the electric motor 100 by utilizing changes in the coil current.

[0025] 7 is a block diagram showing the configuration of a motor behavior sound generation device 200d according to the fourth embodiment. The fourth embodiment differs from the first embodiment only in the internal configuration of the sound source signal generation unit 210, and the other configurations are the same as those of the first embodiment.

[0026] The sound source signal generating unit 210 of the fourth embodiment includes the attenuator 211 used in the first embodiment, the analog Hall IC 212 used in the second embodiment, and a combining unit 215. As described above, the attenuator 211 generates the sound source signal Sc1 corresponding to a change in the coil voltage, and the analog Hall IC 212 generates the sound source signal Sc2 corresponding to a change in the coil current. Note that the pickup coil 213 and pre-amplifier 214 used in the third embodiment may be used instead of the analog Hall IC 212.

[0027] The synthesis unit 215 generates a synthesized sound source signal Scom by synthesizing the first sound source signal Sc1 output from the attenuator 211 and the second sound source signal Sc2 output from the analog Hall IC 212. For example, the synthesis unit 215 may be configured to generate the synthesized sound source signal Scom by multiplying the first sound source signal Sc1 and the second sound source signal Sc2 together. Alternatively, the synthesis unit 215 may be configured to generate the synthesized sound source signal Scom by calculating a weighted sum of the first sound source signal Sc1 and the second sound source signal Sc2. In the latter case, it is preferable that the synthesis unit 215 is configured so that a user inputs a weighting coefficient Kw to the synthesis unit 215. In this embodiment, the attenuator 211 corresponds to a first sound source signal generation unit, and the analog Hall IC 212 corresponds to a second sound source signal generation unit.

[0028] The motor behavior sound generation device 200d of the fourth embodiment can generate more complex sounds according to the behavior of the electric motor 100 by utilizing both changes in coil voltage and changes in coil current.

[0029] 8 is a block diagram showing the configuration of a motor behavior sound generation device 200e in the fifth embodiment. The fifth embodiment differs from the fourth embodiment only in that the synthesis unit 215 is replaced with a selection unit 216, and the other configurations are the same as those of the fourth embodiment.

[0030] The selection unit 216 selects one of the first sound source signal Sc1 output from the attenuator 211 and the second sound source signal Sc2 output from the analog Hall IC 212. The selected selected sound source signal Ss is adjusted by the offset unit 221 and the amplifier 222, similar to the first embodiment. The selection unit 216 is preferably configured to select the sound source signal in response to a selection signal SEL input by the user.

[0031] The motor behavior sound generation device 200e of the fifth embodiment can generate a sound that changes in accordance with the behavior of the electric motor 100 by selecting either a change in coil voltage or a change in coil current.

[0032] If the motor behavior sound generating device of each of the above-described embodiments is installed in a vehicle, it is possible to generate a sound containing sound components corresponding to changes in the torque of the electric motor in response to the operation of the accelerator pedal of the vehicle. In particular, it is possible to generate a sound indicative of changes in the torque of the electric motor that occur when the vehicle accelerates or decelerates. Furthermore, it is possible to enjoy behavior sounds with different characteristics in various electric vehicles such as EVs (electric vehicles) and electric motorcycles, and it is possible to obtain exceptional acoustic effects.

[0033] Furthermore, when an abnormality occurs in an electric motor, a frequency change occurs relative to the coil voltage and coil current during normal operation, and a sound reflecting this change can be generated. Possible abnormalities in an electric motor include, for example, rotor contact vibration, rotor magnet deterioration, load deterioration, bearing deterioration, stator coil insulation deterioration, power supply deterioration (battery deterioration), and centrifugal distortion. By using the motor behavior sound generator of each of the above-mentioned embodiments, it is possible to generate sounds to indicate these abnormalities. Furthermore, because abnormal conditions in an electric motor can be generated as abnormal sounds, this can also be used to support the driver in driving safely and for maintenance to analyze abnormalities.

[0034] Furthermore, while vehicles powered by electric motors have lacked value as vehicles that place value on the sound of an internal combustion engine and the sense of unity created by the accelerator, the motor behavior sound generating device disclosed herein can help build a market that can restore this value. Such advantages are particularly evident when electric motors are used as the main power source in races involving various types of mobility, including automobiles and motorcycles (such as F1 races and mobility races).

[0035] The present disclosure is not limited to the above-described embodiments, embodiments, and variations, and can be realized in various configurations without departing from the spirit thereof. For example, the technical features in the embodiments, embodiments, and variations corresponding to the technical features in each aspect described in the Summary of the Disclosure section can be appropriately replaced or combined to solve some or all of the above-described problems or achieve some or all of the above-described effects. Furthermore, if a technical feature is not described as essential in this specification, it can be deleted as appropriate.

[0036] (1) According to one aspect of the present disclosure, there is provided a motor behavior sound generating device including: a sound source signal generating unit that generates a sound source signal in response to a change in a coil voltage or a coil current of an electric motor; and a signal adjusting unit that applies signal adjusting processing, including signal amplification, to the sound source signal to generate an acoustic signal suitable for input to a speaker. This motor behavior sound generating device generates an acoustic signal from changes in the coil voltage or coil current of the electric motor, so it is possible to generate a sound that changes according to the behavior of the electric motor.

[0037] (2) In the motor behavior sound generating device, the sound source signal generating unit may be configured to generate the sound source signal in response to a change in the coil voltage. This motor behavior sound generating device can generate sounds that change in accordance with the behavior of the electric motor by utilizing changes in coil voltage.

[0038] (3) In the motor behavior sound generating device, the sound source signal generating unit may include an attenuator that receives the coil voltage as an input and outputs the sound source signal. According to this motor behavior sound generating device, a sound source signal corresponding to a change in the coil voltage can be generated by an attenuator.

[0039] (4) In the motor behavior sound generating device, the sound source signal generating unit may be configured to generate the sound source signal in response to a change in the coil current. This motor behavior sound generating device can generate sounds that change according to the behavior of the electric motor by utilizing changes in the coil current.

[0040] (5) In the above motor behavior sound generating device, the sound source signal generating unit may include an analog Hall IC that is arranged near a connection wiring through which the coil current flows and generates the sound source signal in response to a change in the coil current. This motor behavior sound generator can generate a sound source signal that corresponds to changes in coil current using an analog Hall IC.

[0041] (6) In the above motor behavior sound generating device, the sound source signal generating unit may include a pickup coil that is arranged near a connection wiring through which the coil current flows and generates the sound source signal in response to a change in the coil current. According to this motor motion sound generating device, a sound source signal corresponding to a change in coil current can be generated by the pickup coil.

[0042] (7) In the above motor behavior sound generating device, the sound source signal generating unit may include a first sound source signal generating unit that generates a first sound source signal in response to a change in the coil voltage, a second sound source signal generating unit that generates a second sound source signal in response to a change in the coil current, and a synthesis unit that synthesizes the first sound source signal and the second sound source signal to generate a synthesized sound source signal. This motor behavior sound generating device can generate more complex sounds that correspond to the behavior of the electric motor by utilizing both changes in coil voltage and changes in coil current.

[0043] (8) In the above motor behavior sound generating device, the sound source signal generating unit may include a first sound source signal generating unit that generates a first sound source signal in response to a change in the coil voltage, a second sound source signal generating unit that generates a second sound source signal in response to a change in the coil current, and a selecting unit that selects one of the first sound source signal and the second sound source signal. This motor behavior sound generating device can select either a change in coil current or a change in coil voltage to generate a sound that changes in accordance with the behavior of the electric motor.

[0044] (9) In the motor behavior sound generating device, the signal adjustment unit may include an offset unit that offsets a signal level of the sound source signal, and an amplifier that amplifies an output of the offset unit to generate the acoustic signal. This motor motion sound generator allows the acoustic signal to be adjusted to an appropriate signal level. [Explanation of symbols]

[0045] 100...electric motor, 110...electromagnetic coil, 120...drive circuit, 121-124...transistor, 130...connecting wiring, 200a-200e...motor behavior sound generator, 210...sound source signal generator, 211...attenuator, 212...analog Hall IC, 213...pickup coil, 214...preamplifier, 215...synthesizer, 216...selector, 220...signal conditioner, 221...offset unit, 222...amplifier, 222a...automatic gain controller, 222b...audio amplifier, 230...speaker

Claims

1. A motor motion sound generating device, a sound source signal generating unit that generates a sound source signal according to a change in a coil voltage or a coil current of the electric motor; a signal adjustment unit that applies signal adjustment processing including signal amplification to the sound source signal to generate an acoustic signal suitable for input to a speaker; A motor behavior sound generating device including:

2. The motor behavior sound generating device according to claim 1, The motor behavior sound generating device, wherein the sound source signal generating unit is configured to generate the sound source signal in response to a change in the coil voltage.

3. The motor behavior sound generating device according to claim 2, The sound source signal generating unit includes an attenuator that receives the coil voltage as an input and outputs the sound source signal.

4. The motor behavior sound generating device according to claim 1, The motor behavior sound generating device, wherein the sound source signal generating unit is configured to generate the sound source signal in response to a change in the coil current.

5. The motor behavior sound generating device according to claim 4, The sound source signal generating unit includes an analog Hall IC that is arranged near a connection wiring through which the coil current flows and generates the sound source signal in response to changes in the coil current.

6. The motor behavior sound generating device according to claim 4, The sound source signal generating unit includes a pickup coil that is arranged near a connection wiring through which the coil current flows and generates the sound source signal in response to changes in the coil current.

7. The motor behavior sound generating device according to claim 1, The sound source signal generation unit a first sound source signal generating unit that generates a first sound source signal according to a change in the coil voltage; a second sound source signal generating unit that generates a second sound source signal according to a change in the coil current; a synthesis unit that synthesizes the first sound source signal and the second sound source signal to generate a synthesized sound source signal; A motor behavior sound generating device including:

8. The motor behavior sound generating device according to claim 1, The sound source signal generation unit a first sound source signal generating unit that generates a first sound source signal according to a change in the coil voltage; a second sound source signal generating unit that generates a second sound source signal according to a change in the coil current; a selection unit that selects one of the first sound source signal and the second sound source signal; A motor behavior sound generating device including:

9. The motor behavior sound generating device according to claim 1, The signal conditioning unit an offset unit that offsets the signal level of the sound source signal; an amplifier that amplifies the output of the offset unit to generate the acoustic signal; A motor behavior sound generating device including:

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