KR101144013B1 - A sonar system and an impedance matching method - Google Patents

Abstract

transmitter; Transducers; And an impedance matching circuit, wherein the transducer and the impedance matching circuit are formed from an equivalent model corresponding to the measured impedance data of the transducer, the resonance frequency of each of the transducer, the impedance matching circuit, or the transducer and the The resonance frequency of the impedance matching circuit is matched to each other, and the position and interval of the frequency at which the reactance component of the transducer including the impedance matching circuit becomes zero are controlled to expand the bandwidth and increase the power factor value in the sound wave and ultrasonic bands. By presenting an active sonar system and impedance matching method, it is possible to drive efficiently in a wide bandwidth between a transmitter and a transducer in an active sonar system, contributing to the output performance and detection performance of the active sonar system. .

Description

Active sonar system and impedance matching method {A SONAR SYSTEM AND AN IMPEDANCE MATCHING METHOD}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an active sonar system and an impedance matching method, and more particularly, to an active sonar system and an impedance matching method having an impedance matching circuit for wideband, high efficiency driving of an underwater acoustic transducer of an active sonar system.

On land and in the air, electromagnetic waves are used to detect targets by radar, laser or infrared, but sonar (SONAR) is used to detect targets in the water. Active sonar is the ship's essential acoustic equipment, which helps the ship navigate safely and locate threatening underwater objects. The operating principle of an active sonar uses piezoelectric phenomena. When the intensity of the current flowing through a crystal or ceramic exhibiting piezoelectric phenomena changes to a constant frequency, they vibrate and generate sound waves of the same frequency. On the contrary, when the sound wave is received from the outside, electric energy is generated, so analyzing the electric signal can find the components of the sound wave. The equipment that can transmit or receive sound waves is called an active sonar.

In an active sonar system, the impedance matching function corresponding to the electrical interfacing between the transmitter and the transducer is indispensable to efficiently supply the maximum power in a wide band from the transmitter to the load, the transducer. However, most existing methods for impedance matching have a problem that the maximum efficiency is limited to 50% by performing conjugate impedance matching to transmit the maximum power to the load. In particular, this method is not useful for active sonar systems where the output impedance of the transmitter is very small and the supply power is limited.

Therefore, an impedance matching method of minimizing unnecessary reactive power components by canceling only the imaginary component of the impedance of the load as a transducer so as to draw output power from the transmitter with high efficiency may be considered.

However, the electrical characteristics of the transducers matched by these techniques have a large variation in the input impedance and applied power even in the matched frequency domain, and the variation is dependent on the physical characteristics of the transducer itself, which makes it difficult to control the matching technique. have. In order to solve this problem, an impedance matching method that applies filter network synthesis method to the estimated electrical equivalent model of the transducer has been proposed, but impedance matching for minimizing the reactance components required for high efficiency operation due to the physically fixed transducer parameters. The disadvantage is that bandwidth constraints occur.

The problem to be solved by the present invention is to solve the above problems, in configuring an impedance matching circuit from the equivalent model corresponding to the measured impedance data of the transducer, an impedance matching circuit with an increased bandwidth and a power factor value In providing an active sonar system including.

Another problem to be solved by the present invention is to solve the above problems, and to obtain matching circuit component values by controlling the position and interval of the frequency at which the reactance component of the transducer becomes 0 to improve the bandwidth and power factor characteristics The present invention provides an impedance matching method capable of controlling the transducer driving voltage, minimizing leakage current, and minimizing component size.

An object of the present invention, the transmitter modeled by the input power source and the input impedance; A transducer for converting the electrical signal of the transmitter into sound waves or converting sound waves into electrical signals; And an impedance matching circuit for transmitting the amount of power of the transmitter to the transducer between the transmitter and the transducer with high efficiency, wherein the transducer and the impedance matching circuit are measured impedance data of the transducer. From the equivalent model corresponding to the resonance frequency of each of the transducer, the impedance matching circuit or the resonance frequency of the transducer and the impedance matching circuit to each other, the reactance component of the transducer including the impedance matching circuit is It can be achieved by providing an active sonar system that controls the location and spacing of frequencies to be zero, thereby extending the bandwidth and increasing the power factor in the sound and ultrasonic bands.

In the impedance matching method of an active sonar system comprising a transmitter modeled by the input power and the input impedance and a transducer for converting the electrical signal of the transmitter into a sound wave or a sound wave to an electrical signal, The resonant frequency of each of the transducer, the impedance matching circuit, or the equivalent model, corresponding to the measured impedance data of the transducer to transmit the amount of power of the transmitter to the transducer between the transmitter and the transducer with high efficiency Bandwidth and power factor characteristics in the sound wave and ultrasonic bands by matching the resonance frequency of the transducer and the impedance matching circuit to each other and controlling the position and interval of the frequency where the reactance component of the transducer including the impedance matching circuit becomes zero. Dog It characterized in that it can be achieved by providing the impedance matching method.

The transducer may be modeled as an equivalent model in which a capacitor representing electrical characteristics of the transducer and an impedance unit having N stages representing mechanical and acoustic characteristics of the transducer are connected in parallel with each other.

The transducer may be approximated as an equivalent model for the resonant mode of a single mode in a frequency section to be matched when the information of the transducer has multiple modes.

The impedance matching circuit may be an LC resonant circuit including a transformer having a primary terminal and a secondary terminal and including a transformer that raises or lowers the secondary voltage with respect to the primary voltage.

The impedance matching circuit may include a second resonator having a resonant frequency caused by a capacitor of the transducer connected in parallel with an inductor of a secondary side of the transformer and an inductor of the secondary side; And a third resonator having a resonant frequency caused by a capacitor and an inductor connected in series with the first primary side of the transformer.

The resonant frequency may be a series resonant frequency of a first resonator in which an inductor and a capacitor are connected in series in the approximated single mode to model mechanical characteristics of the transducer; A parallel resonance frequency caused by the second resonator; And a series resonance frequency by the third resonator; Can be.

The transducer derives constraints on component values during impedance matching in sound and ultrasonic bands, and has a goodness-of-fit function capable of controlling the position and spacing of frequencies where the reactance component of the transducer becomes zero to improve bandwidth and power factor characteristics. By configuring, it can be configured to obtain matching circuit component values.

The impedance matching method may include: a constraint derivation step of deriving a constraint on a component value of the transducer during impedance matching in a sound wave and an ultrasonic band; And a matching circuit design step of calculating a fitness function and matching circuit component values by calculating positions and intervals of frequencies at which the reactance component of the transducer becomes zero so as to expand the bandwidth and increase the power factor value.

According to the present invention, an impedance matching circuit that cancels the reactance component of the transducer and increases the power factor value enables efficient driving in a wide band between the transmitter and the transducer in the active sonar system, thereby improving output performance of the active sonar system. There is an effect that greatly contributes to the detection performance.

According to the present invention, in the production of active sonar equipment in terms of design characteristics such as driving characteristics, heat dissipation, electrical capacity, and transmission sound pressure of the electric drive unit, it is possible to minimize the unnecessary production of actual models, and to reduce the cost and time. It is possible to control the driving voltage and minimize the leakage current, and to reduce the component size by using the turns ratio of the transformer.

1 is a diagram showing the impedance characteristics according to the frequency of a single mode transducer according to the present invention,
FIG. 2 is a circuit diagram illustrating an electrical equivalent model of an impedance characteristic of a single mode transducer according to the present invention using an electrical lumped element.
3 is a diagram showing the impedance characteristics according to the frequency of the multi-mode transducer according to the present invention,
4 is a circuit diagram showing an electrical equivalent model of an impedance characteristic of a multi-mode transducer according to the present invention using an electrically lumped element,
5 is a circuit diagram showing an electrical equivalent model of an active sonar system transmitter including the single mode transducer according to the present invention;
6 is a circuit diagram illustrating an electrical equivalent model of an active sonar system transmitter including the multi-mode transducer according to the present invention.
7 is a diagram illustrating an impedance matching method for driving broadband and high efficiency from an electrical equivalent model of a transducer according to the present invention.

Hereinafter, an active sonar system and an impedance matching method according to an embodiment of the present invention will be described in detail. 1 is a view showing the impedance characteristics according to the frequency of the sound wave and the ultrasonic band of the single mode (mode) transducer 130 according to the present invention. FIG. 1A illustrates a magnitude value of impedance according to frequency, and FIG. 1B illustrates a phase value of impedance according to frequency. It can be seen that resonance occurs at a frequency near the peak of the impedance phase of FIG. 1 (b), and since the number of resonance points corresponds to the number of modes and is a single mode, only one resonance point exists.

2 is a circuit diagram illustrating an electrical equivalent model of an impedance characteristic of the single mode transducer 120 according to the present invention using an electrical lumped element.

In the process of modeling the single mode characteristic, the single mode transducer 120 includes the first capacitor 121a, the first inductor 121b, and the first resistor 121c that receive the effective power. The first resonant circuit 121 and the electric capacitor 123 representing electrical characteristics of the transducer 120 are connected in series.

3 is a diagram illustrating impedance characteristics according to frequencies of sound waves and ultrasonic bands of the multi-mode transducer 220 according to the present invention. Figure 3 (a) shows the magnitude (magnitude) value of the impedance according to the frequency, (b) shows the phase (phase) value of the impedance according to the frequency. It can be seen that resonance occurs at a frequency near the impedance phase peak value of FIG. 3 (b), and the number of resonance points corresponds to the number of modes.

4 is a circuit diagram illustrating an electrical equivalent model of an impedance characteristic of the multi-mode transducer 220 according to the present invention using an electrical lumped element. The number of modes corresponds to the number of resonance points in FIG. 3, which also corresponds to the number of stages of the equivalent model.

The multi-mode transducer 220 includes a capacitor 225 representing electrical characteristics of the transducer and N stages corresponding to N modes representing mechanical and acoustic characteristics of the transducer in the process of modeling the multi-mode characteristics. Impedance parts having stages) have N resonance circuits connected in parallel with each other.

The N resonant circuits include a first mode capacitor C ₁ 221a for the first resonant mode, a first mode inductor L ₁ 221b, and a first mode resistor R ₁ 221c receiving active power in series. A first mode resonant circuit 221 connected to each other; k-th mode capacitor C _k ; 222a for the k-th resonant mode, k-th mode inductor L _k ; 222b, and k-th mode resistor R _k ; 222c receiving active power in series Resonant circuit 222; And an N-th mode capacitor C _N 223a for the N-th resonant mode, an N-th mode inductor L _N 223b, and an N-th mode resistor R _N 223c connected in series with active power; And a mode resonant circuit 223.

5 is a circuit diagram illustrating an electrical equivalent model of a transmitter of an active sonar system 100 including the single mode transducer 120 according to the present invention. The transmitter of the active sonar system 100 includes a transmitter 110, a transducer 120, and an impedance matching circuit 130.

The transmitter 110 is modeled as an input power source 111 for supplying power and an input impedance 112 corresponding to an internal resistance of the input power source.

The transducer 120 converts an electrical signal of the transmitter 110 applied through the impedance matching circuit 130 into a sound wave or converts a sound wave received from the outside into an electrical signal.

The transducer 120 includes a capacitor 123 representing the electrical characteristics of the transducer and a first capacitor 121a and the inductor 121b representing the mechanical characteristics of the transducer in the process of modeling the single mode characteristic. The first resonator 122 and the resistor 121c receiving the effective power have a resonant circuit 121 connected in series.

The impedance matching circuit 130 is a circuit for transmitting the amount of power from the transmitter 110 to the transducer 120 between the transmitter 110 and the transducer 120 with high efficiency.

The impedance matching circuit 130 includes a transformer having a primary terminal and a secondary terminal and increasing or decreasing a secondary voltage with respect to the primary voltage; Part second resonator having a resonance frequency by said electric capacitor 123 connected in parallel; (131b L _T2) (; and a second winding of the transformer (131) (L _T2 131b) and the second primary winding 132); And a third resonator 133 having a resonant frequency caused by the inductor Ls 133a and the capacitor Cs 133b connected in series to the first side of the transformer 131. It includes.

The impedance matching circuit 130 includes the transformer 131 to control the driving voltage of the transducer 120 and to minimize leakage current, and to prevent the primary side inductor 131a and the secondary side inductor 131b. It is possible to reduce the size of components by using the turns ratio.

The resonant frequency of the transducer 120 corresponds to the resonant frequency of the first resonator 122 in which the capacitor 121a and the inductor 121b are connected in series to model the mechanical characteristics of the transducer. The resonance frequency of the transducer 120 and the impedance matching circuit 130 corresponds to the parallel resonance frequency of the second resonator 132. The resonance frequency of the impedance matching circuit 130 corresponds to the series resonance frequency of the third resonator 133.

The equivalent model of FIG. 2 is obtained from the measured impedance data of the single mode transducer 120 of FIG. 1, and the resonance frequency of each of the transducer 120 and the impedance matching circuit 130 is obtained from the equivalent model, or the transducer. The resonance frequency of the 120 and the impedance matching circuit 130 are matched to each other, and the position and interval of the frequency at which the reactance component of the transducer 120 including the impedance matching circuit 130 becomes zero are controlled. Thus, the bandwidth and power factor in the sound and ultrasonic bands can be increased. A power facator value defined as a cosine component by a phase difference between a voltage and a current output when the transducer 120 is driven is expressed by Equation 1 below.

Where | V | and | I | represents the magnitude of voltage and current, P is the amount of effective power, and can be expressed as the cosine product of voltage magnitude, current magnitude, and phase difference between voltage and current, and phase difference θ of voltage and current is -90 ° to 90 ° Has the value Therefore, the power factor cos θ may be expressed as the ratio of the magnitude product of the voltage and the current to the effective power amount.

The impedance matching circuit 130 is designed to improve the power factor characteristic by minimizing the reactance component such that the voltage and current phase difference of the transducer 120 is reduced, thereby improving the output performance of the transmitter 100 of the active sonar system 100. And improve detection performance. That is, in terms of design elements such as driving characteristics, heat dissipation characteristics, electrical capacity, and transmission sound pressure of the electric drive unit, it is possible to minimize the production of unnecessary real models when manufacturing active sonar equipment and to reduce costs and time.

FIG. 6 is a circuit diagram illustrating an electrical equivalent model of an active sonar system transmitter 200 including the multi-mode transducer 220 according to the present invention. The active sonar system transmitter 200 includes a transmitter 110, a transducer 220, and an impedance matching circuit 230.

The transmitter 110 and the impedance matching circuit 230 have the same configuration as the transmitter 110 and the impedance matching circuit 130 in the active sonar system transmitter 100 including the single mode transducer 120 of FIG. 5. Therefore, detailed description is omitted. However, since the value of the impedance matching circuit 230 of the active sonar system transmitter 200 including the multi-mode transducer 220 varies in the configuration of the transducer, the active sonar system transmitter includes the single mode transducer 120. It is different from the value of the impedance matching circuit 130 element of (100).

The transducer 220 is the same as the circuit diagram represented by the electrical equivalent model of the impedance characteristics of the multi-mode transducer 220 of FIG. 4 using an electrically concentrated element (lumped element), detailed description thereof will also be omitted.

 The equivalent model and impedance matching circuit 230 of FIG. 6 may be converted into an impedance matching circuit 130 for the equivalent model of the single mode transducer 120 as shown in FIG. 5.

As a method for approximating the equivalent mode of the single mode transducer 120 to the equivalent mode to be matched from the equivalent model of the multi-mode transducer 220 of FIG. 6, if the corresponding mode to be matched is the first mode resonance In the case of the circuit 221, the mechanical-acoustic series resonant circuits 222 and 223 other than the corresponding mode to be matched are approximated with the reactance components for the corresponding resonant frequencies, and then the approximate inductive and capacitive reactance components 227. , 228 is included in the electric capacitor 225 representing the electrical characteristics of the transducer 220 and finally approximated in the form of a single mode equivalent model as shown in FIG. 5.

Figure 7 shows the performance of the impedance matching method for driving broadband, high efficiency from the electrical equivalent model of the transducer according to the present invention.

As shown in the figure, first, parameter information of an electrical equivalent circuit that can represent impedance characteristics of a transducer to be matched is used as input data. In this case, when the information of the transducer has a multi-mode in a wide band, an approximate transform (S100) is performed in a single mode equivalent model (FIG. 3) for a resonance mode corresponding to a frequency of interest. Proposed fit function and nonlinear optimization to improve power factor characteristics by deriving constraints on broadband impedance matching of transducer equivalent model and matching circuit component values (S200) and minimizing reactance components of matched transducers in broadband The technique is applied (S300) to derive matching circuit component values (S400).

In the circuit of FIG. 5 including the impedance matching circuit 120 from the approximated transducer equivalent model, the condition that the imaginary component of the total input impedance is minimum in a wide band is closely related to the position and spacing of frequencies where the imaginary component becomes zero. Has In addition, as shown in FIG. 5, the resonance frequencies between the inductors and the capacitors of the resonators 122, 132, and 133 are set to match each other. From these characteristics, the frequency component where the reactance component of the matched transducer becomes zero has a real root, so that the power factor characteristic is maximized, so that the third capacitor 133a or the third inductor 133b of the impedance matching circuit components is maximized. Constraints are derived (S200) and used as boundary conditions for optimal device value estimation (S400).

For example, when the winding ratio N of the transformer is 1, when the transducer impedance of FIG. 3 is matched, an expression for deriving a constraint on the third inductor 133b element having an imaginary component of 0 may be represented by 1 to 1. The resonant frequency (ω _s ) of the third resonator unit can be summarized by Equation 2 below.

here,

And A and B are functions related to ω _S , L ₃ , Q _m , G _m , and C ₀ .

Constraints on the third inductor 133b element of the impedance matching circuit 130 for minimizing the reactance component of the transducer 120 matched therefrom are derived as shown in Equation 3 below.

Where α, β are G _m , Q _m , C ₀ This function is related to , ω _s .

Along with the boundary conditions for the device values, the frequency range is defined by the maximum (ω _max ) and minimum (ω _min ) values of the real root frequencies where the imaginary component of the total input impedance becomes zero, and within the band for matching. Configure the fitness function so that the power factor is close to 1 (phase 0 or imaginary component 0) and apply an optimization method (S300) to the third capacitor (C ₃ ; 133a) or the third inductor (L ₃ ; 133b) element. An optimal device value is derived (S400).

 An example of the mathematical expression of the goodness-of-fit function (F) and the constraints for maximizing the power factor in the band for impedance matching is shown in Equation 4 below.

100: single mode active sonar system transmitter
200: multi-mode active sonar system transmitter
110: transmitter 111: input power
112: input impedance
120: single mode transducer
121: first resonant circuit 121a: first capacitor
121b: first inductor 121c: first resistor
122: first resonator 123, 225: electric capacitor
130, 230: impedance matching circuit 131. 231: transformer
131a and 231a: primary side inductor 131b and 231b: secondary side inductor
132, 232: second resonator 133, 233: third resonator
133a and 233a: third capacitor 133b and 233b: third inductor
220: multi-mode transducer 221: first mode resonant circuit
221a: first mode capacitor 221b: first mode inductor
221c: first mode resistor 222: kth mode resonant circuit
222a: kth mode capacitor 222b: kth mode inductor
222c: kth mode resistor 223: Nth mode resonant circuit
223a: Nth mode capacitor 223b: Nth mode inductor
223c: Nth mode resistor 226: First mode resonator
227: kth mode resonator 228: Nth mode resonator
229: N mode resonator

Claims (14)

A transmitter modeled with input power and input impedance;
A transducer for converting the electrical signal of the transmitter into sound waves or converting sound waves into electrical signals; And
And an impedance matching circuit for transmitting the amount of power of the transmitter to the transducer between the transmitter and the transducer.
The transducer and the impedance matching circuit,
From the equivalent model corresponding to the measured impedance data of the transducer, the resonance frequency of each of the transducer and the impedance matching circuit or the resonance frequencies of the transducer and the impedance matching circuit are matched with each other, and the impedance matching circuit is An active sonar system (SONAR) system, characterized in that to extend the bandwidth and increase the power factor value in the sound wave and ultrasonic band by controlling the position and interval of the frequency that the reactance component of the transducer is zero. The method of claim 1,
The transducer
And a capacitor representing the electrical characteristics of the transducer and an impedance portion having N stages representing the mechanical and acoustic characteristics of the transducer are modeled as an equivalent model. The method of claim 1,
The transducer
Active sonar system, characterized in that to approximate the equivalent model for the resonant mode of a single mode when the information of the transducer has multiple modes. The method of claim 1,
The impedance matching circuit
An active sonar system having a primary terminal and a secondary terminal, the LC resonant circuit including a transformer for raising or lowering the secondary voltage with respect to the primary voltage. The method of claim 4, wherein
The impedance matching circuit
A second resonator having a resonant frequency caused by a capacitor of the transducer connected in parallel with the secondary inductor of the transformer and the secondary inductor; And
And a third resonator having a resonant frequency caused by a capacitor and an inductor connected in series with the primary side of the transformer. The method according to claim 1 or 5,
The resonant frequency is
A series resonant frequency of a first resonator in which an inductor and a capacitor are connected in series to model mechanical characteristics of the transducer;
A parallel resonance frequency caused by the second resonator; And
And a series resonant frequency caused by the third resonator. The method of claim 6,
The transducer
In order to derive constraints on component values when matching impedances in sound and ultrasonic bands, and to improve the bandwidth and power factor characteristics, construct a fitness function to control the position and spacing of frequencies where the reactance component of the transducer becomes zero. An active sonar system configured to obtain matching circuit component values. An impedance matching method of an active sonar system comprising a transmitter modeled with an input power source and an input impedance, and a transducer for converting an electrical signal of the transmitter into a sound wave or a sound wave to an electrical signal,
The resonant frequency of each of the transducer, the impedance matching circuit or the transducer from an equivalent model corresponding to the measured impedance data of the transducer to transfer the amount of power of the transmitter to the transducer between the transmitter and the transducer And matching the resonance frequencies by the impedance matching circuit with each other, and controlling the position and interval of the frequency at which the reactance component of the transducer including the impedance matching circuit becomes zero to improve bandwidth and power factor characteristics in the sound wave and ultrasonic bands. Impedance matching method characterized in that. The method of claim 8,
The transducer
Impedance matching method characterized in that it is modeled by an equivalent model in which a capacitor representing the electrical characteristics of the transducer and an impedance portion having N stages representing the mechanical and acoustic characteristics of the transducer are connected in parallel with each other. The method of claim 8,
The transducer
If the information of the transducer has a multi-mode impedance matching method characterized in that the approximation to an equivalent model for the resonant mode of a single mode. The method of claim 8,
The impedance matching circuit
And an LC resonant circuit having a primary terminal and a secondary terminal and including a transformer for raising or lowering the secondary voltage with respect to the primary voltage. The method of claim 8,
The impedance matching circuit
A second resonator having a resonant frequency caused by a capacitor of the transducer connected in parallel with the inductor on the second side of the transformer and the inductor on the second side; And
And a third resonator having a resonant frequency caused by a capacitor and an inductor connected in series with the primary side of the transformer. The method of claim 8 or 12,
The resonant frequency is
A series resonant frequency of a first resonator in which an inductor and a capacitor are connected in series to model mechanical characteristics of the transducer;
A parallel resonance frequency caused by the second resonator; And
And a series resonant frequency caused by the third resonator. The method of claim 8,
The impedance matching method
A constraint derivation step of deriving a constraint on a component value of the transducer during impedance matching in a sound wave and an ultrasonic band; And
And a matching circuit design step of constructing a fitness function and obtaining matching circuit component values to control the position and spacing of the frequency at which the reactance component becomes zero for extending the bandwidth and increasing the power factor value.

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