| In the process of power line carrier communication,impedance mismatch occurs,which affects the transmission efficiency and communication quality of the whole line.This paper designs an adaptive impedance matching system,which can dynamically solve the problem of impedance mismatch in power line communication.After analyzing the impedance characteristics of the power line,the subject designed a highprecision improved impedance measurement module.The module measures the impedance value of the load terminal through a series of hardware operation circuits by collecting the current signal and the load terminal voltage signal in the power line loop.In the design,24-bit high-precision analogto-digital conversion chip is used for signal acquisition.After testing,the voltage error is controlled within 1%,the current error is within 3%,and the impedance error is controlled within 5%.Aiming at the simple structure and easy operation of L-type impedance matching network,this paper designs an L-type network adaptive impedance matching structure,which can be measured by the improved impedance measurement module and dynamically based on L-type impedance matching analysis.Select the matching network structure that is connected to the circuit.Capacitive inductors in the matching network use variable capacitance inductors.After theoretical analysis and experimental testing,the variable capacitors can be realized by the number of capacitors connected to the relay control circuit.The variable inductors are connected in parallel with the variable capacitors.Equivalent to the method of inductance implementation.After the whole system joint debugging,it is found that with the adaptive matching network designed by the subject,the load output power is increased by nearly 15%.Therefore,the impedance matching system designed in this paper solves the impedance mismatch problem in the power line carrier communication process to some extent. |
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