CN108419186A - Electroacoustic transducer and voice coil vibrations displacement control method - Google Patents
Electroacoustic transducer and voice coil vibrations displacement control method Download PDFInfo
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R9/00—Transducers of moving-coil, moving-strip, or moving-wire type
- H04R9/02—Details
- H04R9/025—Magnetic circuit
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R3/00—Circuits for transducers, loudspeakers or microphones
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R9/00—Transducers of moving-coil, moving-strip, or moving-wire type
- H04R9/06—Loudspeakers
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R2420/00—Details of connection covered by H04R, not provided for in its groups
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
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Abstract
The embodiment of the invention discloses a kind of electroacoustic transducer and voice coil vibrations displacement control methods.Electroacoustic transducer, including：Magnetic circuit system and vibrational system；The magnetic circuit system includes centring magnet and at least a pair of of sideline circle；Pairs of sideline circle is symmetricly set on the both sides of the centring magnet；It is formed with magnetic gap between the centring magnet and sideline circle；Voice coil in the vibrational system is hung in the magnetic gap；It is connected with corresponding operating current/voltage in the voice coil and each sideline circle.Technical solution provided in an embodiment of the present invention, using sideline circle instead of side magnet some or all of in magnetic circuit system, can by adjusting be passed through sideline circle in current or voltage mode, adjust the vibration displacement and magnetic circuit performance of voice coil, so that the BL values of the voice coil tend to constant, electroacoustic transducer is intended to linear working state, achievees the purpose that reduce distortion.
Description
Technical Field
The invention belongs to the technical field of electroacoustic conversion, and particularly relates to an electroacoustic converter and a voice coil vibration displacement control method.
Background
The electroacoustic transducer comprises a vibrating diaphragm, a voice coil and a magnetic circuit system, wherein the voice coil is suspended in a magnetic gap in the magnetic circuit system. When alternating current is supplied, the voice coil moves up and down under the action of magnetic force to drive the vibrating diaphragm to vibrate and drive air to make sound, so that energy conversion from electricity to sound is realized.
The prior electro-acoustic transducer operates at low frequencies and can cause excessive voice coil displacement if high power input occurs. If the voice coil is displaced too much, not only the electroacoustic transducer has a distortion problem, but also the voice coil may rub against other parts inside the electroacoustic transducer, and the too large vibration amplitude may even damage the diaphragm, resulting in damage to the electroacoustic transducer.
Disclosure of Invention
In view of the above, embodiments of the present invention provide an electroacoustic transducer and a voice coil vibration displacement control method, so that the BL value of the voice coil tends to be constant, and the electroacoustic transducer tends to operate linearly.
To solve the technical problems in the prior art, an embodiment of the present invention provides an electroacoustic transducer, including: the vibration control system comprises a magnetic circuit system, a vibration system and a power supply unit; wherein,
the magnetic circuit system comprises a central magnet and at least one pair of side coils;
the paired side coils are symmetrically arranged on two sides of the central magnet;
a magnetic gap is formed between the central magnet and the side coil;
a voice coil in the vibration system is suspended in the magnetic gap;
and the voice coil and each side coil are communicated with corresponding working current/voltage.
Optionally, the electroacoustic converter further comprises: the device comprises a detection unit, a control unit and a power supply unit; wherein,
the detection unit is connected with the control unit;
the control unit is connected with the power supply unit;
the detection unit is configured to detect a real-time current/voltage on the side coil;
the control unit is configured to calculate real-time displacement of the voice coil according to the real-time current/voltage and power supply parameters on the side coil; estimating the target displacement of the voice coil at the next moment based on the real-time displacement, and determining the power supply parameters required to be provided for the side coil at the next moment according to the target displacement;
the power supply unit is configured to supply power to each of the side coils according to the power supply parameter determined by the control unit.
Optionally, an iron core is arranged in the side coil.
Optionally, the magnetic circuit system further comprises at least one pair of side magnets; the paired side magnets are symmetrically arranged on two sides of the central magnet; the side magnets and the side coils are arranged around the central magnet at intervals; the magnetic gap is formed between the center magnet and the side magnets.
Optionally, the lead of the side coil is led out from the electroacoustic transducer housing at the same position as the lead of the voice coil.
The embodiment of the invention also provides a voice coil vibration displacement control method, which comprises the following steps:
calculating real-time displacement of a voice coil suspended in a magnetic gap according to the detected real-time current/voltage on a side coil in a magnetic circuit system of the electroacoustic transducer; the side coils are at least one pair, the side coils in the pair are symmetrically arranged on two sides of a central magnet in the magnetic circuit system, and the magnetic gap is formed between the central magnet and the side coils;
predicting the target displacement of the voice coil at the next moment based on the real-time displacement;
and determining a power supply parameter required to be provided for the side coil at the next moment according to the target displacement so as to adjust the vibration displacement of the voice coil.
Optionally, predicting a target displacement of the voice coil at the next time based on the real-time displacement includes:
obtaining the displacement variable quantity of the voice coil at the next moment according to the displacement trend model corresponding to the audio frequency point loaded by the electroacoustic converter;
and predicting the target displacement of the voice coil at the next moment according to the real-time displacement of the voice coil and the displacement variable quantity.
Optionally, determining, according to the target displacement, a power supply parameter that needs to be provided to the sideline coil at the next time includes:
and acquiring a power supply parameter corresponding to the target displacement as a power supply parameter required to be provided for the sideline coil at the next moment according to a preset corresponding relation between the displacement and the power supply parameter.
Optionally, the method further comprises:
establishing a finite element model of the electroacoustic transducer according to the geometric figure of the electroacoustic transducer;
loading test parameters corresponding to each time interval of a frequency point audio frequency on the finite element model, and carrying out finite element analysis on the finite element model to analyze the ideal displacement of the voice coil at each time interval and the BL value of the voice coil at each time interval; wherein the test parameters include at least: the power supply parameters of the voice coil and the power supply parameters of the side coil;
if the BL value of the voice coil at each time interval meets the constant requirement, obtaining the displacement trend model corresponding to the frequency point based on the ideal displacement of the voice coil at each time interval; obtaining the corresponding relation between the displacement and the power supply parameter based on the ideal displacement of the voice coil at each time interval and the power supply parameter of the side coil corresponding to each time interval;
and if the BL value of the voice coil at each time interval does not meet the constant requirement, adjusting the power supply parameters of the side coil corresponding to part of the time intervals, loading the power supply parameters of the voice coil and the adjusted power supply parameters of the side coil on the finite element model, and carrying out finite element analysis on the finite element model until the BL value of the voice coil at each time interval meets the constant requirement.
Optionally, calculating a real-time displacement of the voice coil suspended in the magnetic gap according to the detected real-time current/voltage on the side coil in the magnetic circuit system of the electroacoustic transducer, including:
calculating the magnetic flux variation inside the magnetic circuit system according to the real-time current/voltage;
and calculating the real-time displacement of the voice coil according to the magnetic flux variation in the magnetic circuit system, the input current of the voice coil and the physical characteristic parameters of the voice coil.
Optionally, the magnetic circuit system further comprises at least one pair of side magnets, and the pair of side magnets are symmetrically arranged on two sides of the central magnet; the side magnets and the side coils are arranged around the central magnet at intervals; the magnetic gap is formed between the central magnet and the side magnets; an iron core is arranged in the side coil; and
calculating the magnetic flux variation inside the magnetic circuit system according to the real-time current/voltage, and the method comprises the following steps:
calculating the magnetic flux inside the side coil according to the real-time current/voltage and the physical characteristic parameters of the side coil;
and calculating the magnetic flux variation in the magnetic circuit system according to the magnetic flux in the side coil, the magnetic flux in the central magnet, the physical characteristic parameters of the side magnet and the physical characteristic parameters of the iron core.
Optionally, the physical characteristic parameters of the side coil include: the number of turns of the coil and the overlooking area of the coil; and
calculating the magnetic flux inside the side coil according to the real-time current/voltage and the physical characteristic parameters of the side coil, wherein the calculation comprises the following steps:
calculating the magnetic flux inside the side coil according to the real-time current, the number of turns of the side coil and the coil overlooking area of the side coil; or
Calculating induced electromotive force on the side coil according to the real-time current and the power supply voltage on the side coil; and calculating the magnetic flux inside the side coil based on the induced electromotive force and the number of turns of the side coil.
According to the technical scheme provided by the embodiment of the invention, the side coil is used for replacing part or all side magnets in the magnetic circuit system, and the vibration displacement and the magnetic circuit performance of the voice coil can be adjusted by adjusting the current or voltage introduced into the side coil, so that the BL value of the voice coil tends to be constant, and the electroacoustic transducer tends to be in a linear working state, and the purpose of reducing distortion is achieved.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
The accompanying drawings, which are included to provide a further understanding of the embodiments of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the embodiments of the invention and not to limit the embodiments of the invention unduly.
In the drawings:
fig. 1 is an exploded schematic view of a five-magnetic-circuit system and a voice coil in an electroacoustic transducer according to an embodiment of the present invention;
fig. 2 is a schematic top view of a five-magnetic-circuit system and a voice coil in an electroacoustic transducer according to an embodiment of the present invention;
fig. 3 is a schematic top view of a three-magnetic-circuit system and a voice coil in an electroacoustic transducer according to an embodiment of the present invention;
fig. 4 is a schematic connection diagram of units included in an electroacoustic transducer according to an embodiment of the present invention;
fig. 5 is a flowchart illustrating a voice coil vibration displacement control method according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments obtained by persons of ordinary skill in the art based on the embodiments of the present invention without any creative efforts shall fall within the protection scope of the embodiments of the present invention.
The inventor finds that when the existing electroacoustic transducer works under a low-frequency condition, the large-power input can cause large displacement of the voice coil, and the excessive displacement not only can cause large distortion, but also can cause the problem that the voice coil collides with other internal components.
The existing protection means is to use intelligent power amplifier to control the input power of the electroacoustic transducer, when the vibration limit of the vibration system of the electroacoustic transducer is exceeded, the input power is reduced to protect the electroacoustic transducer, the power is increased in the limit range, and the acoustic performance of the electroacoustic transducer is improved. The vibration displacement of the voice coil of the vibration system needs to be known for the purpose of protection.
In the prior art, one solution is to estimate the vibration of the vibration system by means of measured data, assuming a theoretical model of the electroacoustic transducer. The method has the defects that the theoretical model is different from the actual model, and the performance of the electroacoustic transducer is not optimized sufficiently. Another solution is to add extra sensor-capacitor plates, which can improve the accuracy of displacement monitoring, but needs to sacrifice part of the space of the electroacoustic transducer module, which causes design difficulty. In addition, neither of the above-mentioned methods can avoid the problem of increased distortion of the electroacoustic transducer at large displacements.
In order to overcome the defects in the prior art, embodiments of the present invention provide an electroacoustic transducer and a voice coil vibration displacement control method. Before describing in detail the embodiments of the present invention, the BL values according to the present invention will be described. The mechanical force generated by the current through the voice coil is represented by the BL value. BL is the length L of the wire for a certain number of turns multiplied by the pass density B per unit area. BL is a parameter for measuring the strength of the driving system, and the BL value can be obtained through measurement. As the voltage applied to the electroacoustic transducer increases, the voice coil becomes more and more distant from the magnetic gap, the number of coils remaining in the magnetic gap decreases, and the BL value also decreases. The main idea of the technical scheme provided by the invention is that the side coils are arranged on two sides of the central magnetic circuit of the magnetic circuit system in pairs, and the BL value of the voice coil is controlled to be constant by changing the current/voltage introduced into the side coils, so that the electroacoustic transducer is in a linear working state, and the purpose of reducing distortion is achieved.
Embodiments of the present invention will be described in detail with reference to the accompanying drawings and embodiments, so that the implementation process of how to apply technical means to solve technical problems and achieve technical effects can be fully understood and implemented.
The same or similar reference numerals in the drawings of the embodiments of the present invention correspond to the same or similar components; in the description of the embodiments of the present invention, it should be understood that, if there are terms such as "upper", "lower", "left", "right", etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the drawings, the terms are only used for convenience in describing the embodiments of the present invention and simplifying the description, but do not indicate or imply that the devices or elements indicated must have specific orientations, be constructed in specific orientations, and be operated, so that the terms describing the positional relationships in the drawings are only used for illustrative purposes and are not to be construed as limiting the embodiments of the present invention, and the specific meanings of the terms may be understood by those skilled in the art according to specific situations.
Fig. 1, 2 and 3 are schematic structural diagrams illustrating partial components of an electroacoustic transducer provided according to an embodiment of the present invention. An embodiment of the present invention provides an electroacoustic transducer, including: magnetic circuit system and vibration system. As shown in fig. 1, 2 and 3, the magnetic circuit system includes: a central magnet 11 and at least one pair of side coils 12. The pair of side coils 12 are symmetrically arranged at both sides of the central magnet 11, a magnetic gap is formed between the central magnet 11 and the side coils 12, and the voice coil 10 in the vibration system is suspended in the magnetic gap. The voice coil 10 and each side coil 12 are supplied with corresponding operating current/voltage.
Fig. 1 and 2 show an example of a five-magnetic-circuit system, which includes a center magnet 11, a pair of long-side magnets 14 located on two opposite sides of the center magnet, and a pair of short-side coils 12 located on two opposite sides of the center magnet. Fig. 3 shows an example of a three-way magnetic circuit system, i.e. the magnetic circuit system comprises a central magnet 11 and a pair of side coils 12 located at two opposite sides of the central magnet.
According to the technical scheme provided by the embodiment of the invention, the side coil is used for replacing part or all side magnets in the magnetic circuit system, and the vibration displacement and the magnetic circuit performance of the voice coil can be adjusted by adjusting the current or voltage introduced into the side coil, so that the BL value of the voice coil tends to be constant, and the electroacoustic transducer tends to be in a linear working state, and the purpose of reducing distortion is achieved.
In practical application, an iron core 13 may be further disposed in each side coil 12 to improve magnetic permeability.
Further, the operating current/voltage passed through each side coil may be provided by a power supply unit controlled by a controller of an external device. The external device may be a mobile phone, a tablet computer, or the like, which is installed with the electroacoustic transducer provided in this embodiment, and this is not particularly limited in this embodiment of the present invention.
Alternatively, the electroacoustic transducer has built in modules/module assemblies for controlling the current or voltage to the side coils. For example, in an implementable technical solution, as shown in fig. 4, the electroacoustic transducer provided in the above embodiment may further include: detection unit 15, control unit 16, and power supply unit 17. Wherein, the detection unit 15 is connected with the control unit 16; the control unit 16 is connected to a power supply unit 17. The detection unit 15 is configured to detect the real-time current/voltage on the side coil 12; the control unit 16 is configured to calculate the real-time displacement of the voice coil 10 from the real-time current/voltage and the power supply parameters on the side coil 12; estimating the target displacement of the voice coil at the next moment based on the real-time displacement, and determining the power supply parameters required to be provided for the side coil at the next moment according to the target displacement; the power supply unit 17 is configured to supply power to each side coil 12 in accordance with the power supply parameter determined by the control unit 16.
Here, it should be noted that: the specific working principle of the control unit can be seen from the corresponding content in the subsequent embodiments.
In the embodiment of the present invention, the central magnet 11 includes, but is not limited to, a rectangular structure, and the pair of side coils 12 may be respectively disposed at two short side positions and/or two long side positions of the rectangular structure.
With continued reference to fig. 1 and 2, the magnetic circuit system further includes at least one pair of side magnets 14. The edge magnets 14 may be disposed at two short edge positions and/or two long edge positions of the rectangular structure, respectively. In one implementation, the pairs of side magnets 14 are symmetrically disposed on both sides of the central magnet 11, and the side magnets 14 are spaced apart from the side coils 12 around the central magnet. A magnetic gap is formed between the center magnet 11 and the side magnets 14.
In a specific implementation, the position of the lead of the side coil 12 led out from the electroacoustic transducer housing may be the same as the lead led-out position of the voice coil 10, or may be different from the lead led-out position of the side coil.
Referring to fig. 5, an embodiment of the present invention further provides a voice coil vibration displacement control method. The main execution body of the method provided by the embodiment may be a device (such as a mobile phone, a tablet computer, etc.) equipped with an electroacoustic transducer, or may be a module/module assembly (such as a controller) built in the electroacoustic transducer for controlling the current or voltage passed into the side coil. Specifically, the voice coil vibration displacement control method comprises the following steps:
step S101, calculating real-time displacement of a voice coil suspended in a magnetic gap according to the detected real-time current/voltage on a side coil in a magnetic circuit system of the electroacoustic transducer.
It should be noted here that the method provided by the present embodiment is applicable to the electroacoustic transducer provided by the above embodiment. That is, referring to fig. 1, 2 and 3, the electroacoustic transducer includes: magnetic circuit system and vibration system. Wherein, magnetic circuit includes: a central magnet 11 and at least one pair of side coils 12. The pair of side coils 12 are symmetrically arranged at both sides of the central magnet 11, a magnetic gap is formed between the central magnet 11 and the side coils 12, and the voice coil 10 in the vibration system is suspended in the magnetic gap. The voice coil 10 and each side coil 12 are supplied with corresponding operating current/voltage.
And S102, estimating the target displacement of the voice coil at the next moment based on the real-time displacement.
And step S103, determining power supply parameters which need to be provided for the sideline coil at the next moment according to the target displacement so as to adjust the vibration displacement of the voice coil.
The step S101 may include the following steps, that is, the step S101 may include:
and S1011, calculating the magnetic flux variation in the magnetic circuit system according to the real-time current/voltage.
It should be noted that, although the calculation methods of the magnetic flux variation amounts in the magnetic paths of different structures, such as the five-magnetic-path system (as shown in fig. 1 and 2) and the three-magnetic-path system (as shown in fig. 3), are different, the calculation methods are the same in principle. The following describes a process for calculating the amount of change in magnetic flux inside the magnetic circuit system, taking the five-magnetic circuit system shown in fig. 1 and fig. 2 (see the above embodiment for details) as an example. The specific implementation process is as follows:
first, the magnetic flux inside the side coil is calculated based on the real-time current/voltage and the physical characteristic parameters of the side coil. In specific implementation, the magnetic flux inside the coil can be obtained based on the following two formulas (1) and (2).
Itest＝Φout/(Nout*Sout) (1)
Wherein Itest is the detected real-time current on the side coil, Nout is the turn number of the side coil, and Sout is the overlooking area of the side coil; Φ out is the magnetic flux inside the side coil; e (t) is the induced electromotive force of the side coil.
Itest in the formula (1) can be obtained by detecting the current on the side coil; the above equation (1) is modified as: the magnetic flux Φ out inside the side coil is obtained as an Itest Nout Sout.
In the above formula (2), e (t) can be calculated based on the real-time voltage detected on the leads at the two ends of the side coil in real time and the working voltage provided by the power supply unit for the side coil at each moment. By integrating the above equation (3), the magnetic flux Φ out inside the side coil can be obtained.
In summary, the magnetic flux inside the side coil can be calculated through real-time current or voltage.
Then, the amount of change in the magnetic flux inside the magnetic circuit system is calculated from the magnetic flux inside the side coils, the magnetic flux inside the center magnet, the physical characteristic parameters of the side magnets, and the physical characteristic parameters of the iron core. The physical characteristic parameter of the edge magnet may be a cross-sectional area of the edge magnet. The physical characteristic parameter of the core may be a core sectional area. Specifically, the amount of change in magnetic flux inside the magnetic circuit system can be obtained based on the following formula (3).
Φout＝(Φ1+Φ2)*A2/(A1+A2) (3)
Where Φ out is a magnetic flux inside the side coil, Φ 1 is a magnetic flux inside the center magnet, Φ 2 is a magnetic flux change inside the magnetic circuit system, a1 is a side magnet sectional area, and a2 is a core sectional area inside the side coil. Since Φ 1, a1, a2 are known, Φ out can be calculated in the above formula (1) or (2), and the amount of change in magnetic flux Φ 2 inside the magnetic circuit system can be calculated by the above formula (3).
And S1012, calculating the real-time displacement of the voice coil according to the magnetic flux variation in the magnetic circuit system, the input current of the voice coil and the physical characteristic parameters of the voice coil.
The physical characteristic parameter of the voice coil is the overlook area of the voice coil. In specific implementation, the following formula (4) can be used to calculate the real-time displacement of the voice coil:
Φ2＝μ0*N(Δd)*Ivoice coil*SVoice coil(4)
Where Φ 2 is the amount of change in magnetic flux inside the magnetic circuit system, μ 0 is the vacuum permeability, N (Δ d) is the relationship between the number of turns of the voice coil in the magnetic gap and the displacement, and IVoice coilIs the input current of the voice coil, SVoice coilIs the area of the voice coil viewed from above.
By converting the above formula (4), N (Δ d) ═ Φ 2/(μ 0 × I) can be obtainedVoice coil*SVoice coil). Since N (Δ d) is a relationship between the number of turns of the voice coil in the magnetic gap and the displacement, the displacement of the voice coil (i.e., the above-mentioned real-time displacement of the voice coil) can be obtained by obtaining the value of N (Δ d).
Note that μ 0 and IVoice coilAnd SVoice coilAre all parameters known in advance.
In an implementation scheme, the above S102 may be implemented by the following method:
and S1021, obtaining the displacement variable quantity of the voice coil at the next moment according to the displacement trend model corresponding to the audio frequency point loaded by the electroacoustic converter.
And S1022, estimating the target displacement of the voice coil at the next moment according to the real-time displacement and the displacement variable quantity of the voice coil.
And during specific implementation, superposing the displacement variable quantity on the real-time displacement of the voice coil to obtain the target displacement of the voice coil. Assuming that the real-time displacement of the voice coil is D1, the displacement variation is D, and the target displacement is D2, the estimation algorithm can be characterized as: d2 ═ D1+ D, where the displacement variation D may be positive, or may be negative or zero.
It should be noted here that the frequency points of the audio loaded by the electroacoustic transducer are different, and the corresponding voice coil displacement trend models are different. Therefore, when the displacement variation of the voice coil at the next moment is estimated, a voice coil displacement trend model corresponding to the currently loaded audio frequency point of the electroacoustic converter needs to be selected.
The voice coil displacement trend model can be obtained through multiple experimental measurements and according to the measurement results; or simulated by simulation software, which is not limited in the embodiments of the present invention.
The power supply parameter provided to the sideline coil at the next moment in the above step 103 can be determined based on the preset corresponding relationship between the displacement and the power supply parameter. In an implementation scheme, the above S103 can be implemented by the following method:
and acquiring a power supply parameter corresponding to the target displacement as a power supply parameter required to be provided for the sideline coil at the next moment according to the preset corresponding relation between the displacement and the power supply parameter.
The corresponding relationship between the displacement and the power supply parameter can be represented as one or more functions, and the target displacement is used as the input of the corresponding relationship between the displacement and the power supply parameter, so that the power supply parameter (such as current/voltage) of the side coil can be calculated. Alternatively, the corresponding relationship between the displacement and the power supply parameter is in the form shown in table 1 below.
TABLE 1 corresponding relationship between displacement and power supply parameters
| Voice coil displacement | Power supply parameter |
| D1 | I1/U1 |
| D2 | I2/U2 |
| …… | …… |
And obtaining the power supply parameters of the side coil corresponding to the target displacement of the voice coil by querying the table. Because the voice coil displacement in the corresponding relationship represented by table 1 is not continuous, in practical application, the situation that the side coil power supply parameter corresponding to the target voice coil displacement cannot be queried may occur. At this time, an interpolation algorithm can be selected to calculate the power supply parameters corresponding to the voice coil displacements that are not included in the table. For example, the target displacement of the voice coil calculated by the method is D3, the power supply parameter corresponding to D3 cannot be found in table 1, and if D3 is between D1 and D2, the power supply parameter corresponding to D3 can be calculated by an interpolation algorithm based on the power supply parameters corresponding to D1 and D2. For specific implementation of the interpolation algorithm, reference may be made to relevant contents in the prior art, and details are not described here.
The corresponding relation between the displacement and the power supply parameter can be obtained through multiple times of experimental measurement and according to the measurement result; or by simulation with simulation software, which is not limited in the embodiments of the present invention.
According to the technical scheme provided by the embodiment of the invention, the side coil is used for replacing part or all side magnets in the magnetic circuit system, and the vibration displacement and the magnetic circuit performance of the voice coil can be adjusted by adjusting the current or voltage introduced into the side coil, so that the BL value of the voice coil tends to be constant, and the electroacoustic transducer tends to be in a linear working state, and the purpose of reducing distortion is achieved.
The voice coil in the electroacoustic transducer is a structural component which drives the vibrating diaphragm to vibrate together to make the electroacoustic transducer produce sound. The voice coil is stressed because the voice coil is positioned in a magnetic field and is internally communicated with current vertical to a magnetic induction line, the voice coil is a special component in simulation analysis, and a finite element analysis model can be created in finite element software; carrying out finite element analysis on the finite element analysis model to obtain a BL value of the voice coil; and then, the analyzed voice coil BL value tends to be constant by continuously adjusting the test parameters (such as voice coil power supply parameters and sideline coil power supply parameters) loaded on the finite element analysis model. Therefore, the corresponding relation between the voice coil displacement trend model and the displacement and power supply parameters can be obtained based on the test parameters loaded on the finite element analysis model when the BL value tends to be constant. Namely, the voice coil vibration displacement control method provided by the embodiment of the invention further comprises a step of creating a corresponding relation between the voice coil displacement trend model and the displacement and power supply parameters. Specifically, the method may further include:
and S104, establishing a finite element model of the electroacoustic transducer according to the geometric figure of the electroacoustic transducer.
And S105, loading test parameters corresponding to each time interval of a frequency point audio frequency on the finite element model, and carrying out finite element analysis on the finite element model to analyze the ideal displacement of the voice coil in each time interval and the BL value of the voice coil in each time interval.
Wherein the test parameters at least include: and power supply parameters of the voice coil and the side coil.
S106, if the BL value of the voice coil at each time interval meets the constant requirement, obtaining a voice coil displacement trend model corresponding to the frequency point based on the ideal displacement of the voice coil at each time interval; and obtaining the corresponding relation between the displacement and the power supply parameter based on the ideal displacement of the voice coil at each time interval and the power supply parameter of the side coil corresponding to each time interval.
And S107, if the BL value of the voice coil at each time interval does not meet the constant requirement, adjusting the power supply parameters of the side coils corresponding to part of the time intervals, loading the power supply parameters of the voice coil and the adjusted power supply parameters of the side coils on the finite element model, and carrying out finite element analysis on the finite element model until the BL value of the voice coil at each time interval meets the constant requirement.
In S104, the geometric figure of the electroacoustic transducer may be obtained by drawing using three-dimensional drawing software. The structure and size of the geometric figure need to be the same as those of the actual electroacoustic transducer product, and after the geometric figure is obtained, a finite element model of the electroacoustic transducer can be established by adopting the following process.
Step 1, importing the geometric figure of the electroacoustic transducer into grid division software, and dividing the grid to obtain a body unit.
And 2, defining unit types, material properties and the like for each body unit, and completing the establishment of the finite element model.
For example, the body unit of each part in the magnetic circuit system of the electroacoustic transducer needs to use the unit type with magnetic freedom adapted thereto. The corresponding unit type containing magnetic freedom degree can be configured for the body unit by defining the unit type so as to facilitate subsequent analysis. The material properties of the magnets in the magnetic circuit of the electroacoustic transducer may be defined as permanent magnets; the material properties of the magnetic conductive yoke may be defined as a ferromagnetic material; the material properties of a voice coil in a vibration system may be defined as a magnetically permeable medium with a fixed magnetic permeability; and so on.
In the above S105, the vibration displacement of the voice coil at each time is different for different audio frequencies. Therefore, when performing the finite element analysis, the test parameters corresponding to each time period of a certain frequency point need to be loaded on the finite element model to analyze the ideal displacement of the voice coil at each time period and the BL value of the voice coil at each time period.
The constant requirements in S106 and S107 described above may be: whether the BL value of the voice coil is equal to a set value; or whether the BL value of the voice coil is within a preset range. Wherein the set value and the preset range can be set based on experience.
The above process of adjusting the power supply parameters of the side coils can be simply understood as the following process:
when the side coil 12 is energized with direct current, the performance of the magnetic circuit system can be changed. When the displacement of the voice coil 10 is increased, the current of the side coil is increased, the magnetic flux of the magnetic circuit system is increased, and the magnetic circuit can be enhanced; when the displacement of the voice coil 10 is reduced, the current of the side coil is reduced, the magnetic flux of a magnetic circuit system is reduced, and the magnetic circuit can be weakened; so that the BL value of the voice coil at each period tends to be constant. The amount of the coil current may be a fixed value or a variable value, which may be set manually, and is not limited in this embodiment of the present invention.
It should be noted that, although the detailed description of the embodiments of the present invention is provided in conjunction with the drawings, the present invention should not be construed as limiting the scope of the embodiments of the present invention. Various modifications and changes may be made by those skilled in the art without inventive step within the scope of the appended claims.
The examples of the embodiments of the present invention are intended to briefly describe the technical features of the embodiments of the present invention, so that those skilled in the art can intuitively understand the technical features of the embodiments of the present invention, and the embodiments of the present invention are not unduly limited.
The above-described apparatus embodiments are merely illustrative, wherein the units described as separate components may or may not be physically separate. One of ordinary skill in the art can understand and implement it without inventive effort.
The foregoing description shows and describes several preferred embodiments of the invention, but as aforementioned, it is to be understood that the embodiments are not limited to the forms disclosed herein, but are not to be construed as excluding other embodiments and may be utilized in various other combinations, modifications, and environments and is capable of changes within the scope of the application as described herein, commensurate with the above teachings, or the skill or knowledge of the relevant art. And that modifications and variations may be effected by those skilled in the art without departing from the spirit and scope of the embodiments of the invention as defined by the appended claims.
Claims (12)
1. An electro-acoustic transducer, comprising: a magnetic circuit system and a vibration system; wherein,
the magnetic circuit system comprises a central magnet and at least one pair of side coils;
the paired side coils are symmetrically arranged on two sides of the central magnet;
a magnetic gap is formed between the central magnet and the side coil;
a voice coil in the vibration system is suspended in the magnetic gap;
and the voice coil and each side coil are communicated with corresponding working current/voltage.
2. The electroacoustic converter of claim 1 further comprising: the device comprises a detection unit, a control unit and a power supply unit; wherein,
the detection unit is connected with the control unit;
the control unit is connected with the power supply unit;
the detection unit is configured to detect a real-time current/voltage on the side coil;
the control unit is configured to calculate a real-time displacement of the voice coil from the real-time current/voltage; estimating the target displacement of the voice coil at the next moment based on the real-time displacement, and determining the power supply parameters required to be provided for the side coil at the next moment according to the target displacement;
the power supply unit is configured to supply power to each of the side coils according to the power supply parameter determined by the control unit.
3. The electroacoustic converter of claim 1 wherein said side coils are provided with iron cores therein.
4. The electroacoustic converter of any of claims 1 to 3 wherein the magnetic circuit system further comprises at least one pair of side magnets;
the paired side magnets are symmetrically arranged on two sides of the central magnet;
the side magnets and the side coils are arranged around the central magnet at intervals;
the magnetic gap is formed between the center magnet and the side magnets.
5. The electroacoustic converter of any of claims 1 to 3,
the lead of the side coil is led out from the shell of the electroacoustic transducer at the same position as the lead of the voice coil.
6. A voice coil vibration displacement control method is characterized by comprising the following steps:
calculating real-time displacement of a voice coil suspended in a magnetic gap according to the detected real-time current/voltage on a side coil in a magnetic circuit system of the electroacoustic transducer; the side coils are at least one pair, the side coils in the pair are symmetrically arranged on two sides of a central magnet in the magnetic circuit system, and the magnetic gap is formed between the central magnet and the side coils;
predicting the target displacement of the voice coil at the next moment based on the real-time displacement;
and determining a power supply parameter required to be provided for the side coil at the next moment according to the target displacement so as to adjust the vibration displacement of the voice coil.
7. The method of claim 6, wherein estimating a target displacement of the voice coil at a next time based on the real-time displacement comprises:
obtaining the displacement variation of the voice coil at the next moment based on a displacement trend model corresponding to the audio frequency points loaded by the electroacoustic converter;
and predicting the target displacement of the voice coil at the next moment according to the real-time displacement of the voice coil and the displacement variable quantity.
8. The method of claim 7, wherein determining the power supply parameters to be provided to the sideline coil at the next moment according to the target displacement comprises:
and acquiring a power supply parameter corresponding to the target displacement as a power supply parameter required to be provided for the sideline coil at the next moment according to a preset corresponding relation between the displacement and the power supply parameter.
9. The method of claim 8, further comprising:
establishing a finite element model of the electroacoustic transducer according to the geometric figure of the electroacoustic transducer;
loading test parameters corresponding to each time interval of a frequency point audio frequency on the finite element model, and carrying out finite element analysis on the finite element model to analyze the ideal displacement of the voice coil at each time interval and the BL value of the voice coil at each time interval; wherein the test parameters include at least: the power supply parameters of the voice coil and the power supply parameters of the side coil;
if the BL value of the voice coil at each time interval meets the constant requirement, obtaining the displacement trend model corresponding to the frequency point based on the ideal displacement of the voice coil at each time interval; obtaining the corresponding relation between the displacement and the power supply parameter based on the ideal displacement of the voice coil at each time interval and the power supply parameter of the side coil corresponding to each time interval;
and if the BL value of the voice coil at each time interval does not meet the constant requirement, adjusting the power supply parameters of the side coil corresponding to part of the time intervals, loading the power supply parameters of the voice coil and the adjusted power supply parameters of the side coil on the finite element model, and carrying out finite element analysis on the finite element model until the BL value of the voice coil at each time interval meets the constant requirement.
10. The method of any one of claims 6 to 9, wherein calculating the real-time displacement of the voice coil suspended in the magnetic gap based on the detected real-time current/voltage on the side coil of the magnetic circuit system of the electroacoustic transducer comprises:
calculating the magnetic flux variation inside the magnetic circuit system according to the real-time current/voltage;
and calculating the real-time displacement of the voice coil according to the magnetic flux variation in the magnetic circuit system, the input current of the voice coil and the physical characteristic parameters of the voice coil.
11. The method of claim 10, wherein the magnetic circuit further comprises at least one pair of side magnets, the pair of side magnets being symmetrically disposed on both sides of the center magnet; the side magnets and the side coils are arranged around the central magnet at intervals; the magnetic gap is formed between the central magnet and the side magnets; an iron core is arranged in the side coil;
calculating the magnetic flux variation inside the magnetic circuit system according to the real-time current/voltage, and the method comprises the following steps:
calculating the magnetic flux inside the side coil according to the real-time current/voltage and the physical characteristic parameters of the side coil;
and calculating the magnetic flux variation in the magnetic circuit system according to the magnetic flux in the side coil, the magnetic flux in the central magnet, the physical characteristic parameters of the side magnet and the physical characteristic parameters of the iron core.
12. The method of claim 11, wherein the physical characteristic parameters of the side coil comprise: the number of turns of the coil and the overlooking area of the coil;
calculating the magnetic flux inside the side coil according to the real-time current/voltage and the physical characteristic parameters of the side coil, wherein the calculation comprises the following steps:
calculating the magnetic flux inside the side coil according to the real-time current, the number of turns of the side coil and the coil overlooking area of the side coil; or
Calculating induced electromotive force on the side coil according to the real-time current and the power supply voltage on the side coil; and calculating the magnetic flux inside the side coil based on the induced electromotive force and the number of turns of the side coil.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201810361102.4A CN108419186B (en) | 2018-04-20 | 2018-04-20 | electroacoustic transducer and voice coil vibration displacement control method |
| PCT/CN2018/093363 WO2019200715A1 (en) | 2018-04-20 | 2018-06-28 | Electroacoustic transducer and method for controlling vibration displacement of voice coil |
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| CN201810361102.4A CN108419186B (en) | 2018-04-20 | 2018-04-20 | electroacoustic transducer and voice coil vibration displacement control method |
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| CN110545506A (en) * | 2019-11-04 | 2019-12-06 | 共达电声股份有限公司 | Loudspeaker |
| WO2024069124A1 (en) * | 2022-09-30 | 2024-04-04 | Cirrus Logic International Semiconductor Limited | Vibrational transducer control |
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| CN206851025U (en) * | 2017-07-03 | 2018-01-05 | 歌尔科技有限公司 | Acoustical generator and the sonification system including the acoustical generator |
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| US20160345114A1 (en) * | 2015-05-21 | 2016-11-24 | Analog Devices, Inc. | Optical and capacitive sensing of electroacoustic transducers |
| CN106303883A (en) * | 2016-08-23 | 2017-01-04 | 歌尔股份有限公司 | A kind of detect the method for loudspeaker voice coil vibration displacement, device and loudspeaker monomer |
| CN206851025U (en) * | 2017-07-03 | 2018-01-05 | 歌尔科技有限公司 | Acoustical generator and the sonification system including the acoustical generator |
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| CN108419186B (en) | 2019-12-06 |
| WO2019200715A1 (en) | 2019-10-24 |
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