Sonar Impedance Matching Circuit Resonant Frequency Control
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Solution Overview
Problem
Conventional impedance matching methods for active SONAR systems are limited in efficiency, typically achieving only up to 50% maximum power transfer due to high deviations in input impedance and supplied power, and are not suitable for systems with low output impedance and limited power supply, especially in underwater applications.
Innovation Solution
An impedance matching circuit and method that utilize an electrical equivalent model to match resonant frequencies between the transducer and the impedance matching circuit, controlling the positions and intervals of reactance components to expand bandwidth and increase power factor, while minimizing reactance components and physical component sizes, using an LC resonant circuit with a transformer to optimize power transfer in acoustic and ultrasonic wave bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional conjugate impedance matching is used to maximize power transfer, then maximum power can be transferred to the load, but the efficiency is limited to 50% due to high reactive power components
Solution Approach 1:
The patent changes the impedance matching approach from conventional conjugate matching to a method that minimizes reactive power components. By adjusting the matching circuit parameters (inductance and capacitance values) to cancel out reactive components rather than achieving conjugate match, the system reduces reactive power loss and improves efficiency beyond the 50% limitation of traditional methods.
Solution Approach 2:
The patent converts the harmful reactive power components into beneficial effects by using them to tune the resonant frequency of the matching circuit. By designing the matching circuit to resonate at the operating frequency, the reactive components cancel each other out, transforming what would be energy-wasting reactance into a mechanism for improving power transfer efficiency.
2Power
If impedance matching is performed to maximize power transfer, then power efficiency improves, but the bandwidth is limited due to physical characteristics of the transducer
Solution Approach 1:
The patent employs a dynamic impedance matching approach where the matching circuit can be adjusted to different frequencies. By making the matching circuit tunable through variable inductors or capacitors, the system can adapt to different operating frequencies and maintain high efficiency across a broader bandwidth, overcoming the fixed bandwidth limitation of conventional matched designs.
Solution Approach 2:
The patent designs the impedance matching circuit to serve multiple functions: it provides impedance transformation, reactive power compensation, and frequency tuning capabilities. This multi-functional design allows the same circuit to operate efficiently across a wider frequency range, enhancing both power transfer efficiency and bandwidth simultaneously.
3Device complexity
If the impedance matching circuit uses fixed parameters, then the design is simple, but the bandwidth is constrained by the physical characteristics of the transducer
Solution Approach 1:
The patent transitions from fixed-parameter to dynamic-parameter impedance matching circuits. By incorporating variable inductors, variable capacitors, or digitally controllable impedance elements, the circuit can be adjusted to different frequencies and conditions, providing both simplicity in basic design and flexibility in operation across extended bandwidths.
4Power
If conventional impedance matching methods are used, then maximum power can be transferred, but large deviations in input impedance and supplied power occur even within the matched frequency range
Solution Approach 1:
The patent incorporates feedback mechanisms where the impedance matching circuit continuously monitors and adjusts its parameters to maintain optimal matching conditions. By using feedback from the transducer's actual impedance characteristics, the system can compensate for variations and maintain stable input impedance and supplied power across the operating frequency range, reducing large deviations.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enhances the power factor and bandwidth of the active SONAR system, improving output power performance and detection capabilities, while minimizing leakage current and reducing the physical size of components, thereby reducing production costs and time.
Implementation Method 1
mutually matching resonant frequencies of the transducer and the impedance matching circuit or a resonant frequency between the transducer and the impedance matching circuit
Implementation Method 2
An operating principle of the active SONAR is to use a piezoelectric effect. When the current in a predetermined frequency flows on piezoelectric crystal or ceramic, the crystal or ceramic vibrates to generate acoustic waves of the same frequency.
Implementation Method 3
a transducer configured to convert an electrical signal of the transmitter into an acoustic wave or the acoustic wave into the electrical signal
Data Source
AI summary
This specification relates to an active SONAR system comprising a transmitter, a transducer and an impedance matching circuit for expanding bandwidth and increasing a power factor value in sound and ultrasonic wave bands by mutually matching resonant frequencies of the transducer and the impedance matching circuit or a resonant frequency between the transducer and the impedance matching circuit using an electrical equivalent model corresponding to actual impedance data of the transducer and controlling the positions and the intervals of the frequencies at which reactance components of the transducer including the impedance matching circuit become zero, and an impedance matching method thereof. This allows for efficient driving in a broadband between the transmitter and the transducer in the active SONAR system, contributing to output power performance and detection performance of the active SONAR system.