Automatic matching system and method of pi-type impedance in radio frequency energy collection circuit

Abstract

The invention relates to an automatic matching system and method of pi-type impedance in a radio frequency energy collection circuit. The system comprises a sampling comparison module, a logic algorithm control module, and an adjustable impedance matching network. The sampling comparison module is used for consecutively sampling voltages output by a voltage doubling rectifying circuit twice under the control of a differential operator method of the logic control module and comparing the voltages consecutively sampled twice. The logic algorithm control module is used for determining, according to a comparison result of the voltages consecutively sampled twice, a capacitor adjustment direction of a pi-type adjustable capacitor array and adjusting a quantity of adjustable capacitors integrated in the adjustable impedance matching network according to capacitance weights by using a capacitance dichotomy according to the capacitor adjustment direction. The adjustable impedance matching network is used for matching impedances of an antenna and the voltage doubling rectifying circuit according to the quantity of capacitors integrated in the pi-type adjustable capacitor array. The circuit is simple, has extremely low power consumption, consumes energy only in an on and off process, and is applicable to a weak energy collection environment.

Description

technical field [0001] The invention relates to a system and method for impedance matching in an energy collection circuit, in particular to a π-type impedance automatic matching system and method in a radio frequency energy collection circuit. Background technique [0002] Due to the vigorous development of wireless sensor network (WSN), body area network (BAN), and Internet of Things (IoT), wireless sensor nodes have been widely utilized. In order to achieve uninterrupted measurement, the sensor node needs to have a longer standby time, but its service life is limited by the bottleneck of battery technology. In order to solve the power supply problem of sensor nodes, wireless energy harvesting technology has been widely developed, which collects radio energy to provide power for sensor nodes, so as to achieve the purpose of prolonging the working time of the circuit or passive work. [0003] Energy harvesting circuits generally consist of four parts, such as figure 1 As ...

AI Technical Summary

Problems solved by technology

[0012] 1. The system requires a coupler to detect the forward power signal and the reflected power signal. However, this component cannot be integrated with a CMOS process, which increases the complexity of the system;

[0013] 2. This system is too complicated. The system first needs the ADC to sample the voltage signal, then uses the processor unit to calculate the current transmission efficiency, and then controls the matching network to change until the efficiency meets the program requirements. This method has a large power consumption and cannot be applied In weak energy harvesting systems;

[0014] 3. The system uses a relay as a control unit, which is suitable for high-power transmission, but in the energy harvesting circuit, the collected energy is not enough to control components such as relays

This method also faces the problems of complex system, inability to integrate, and high power consumption, and cannot be applied to weak energy harvesting circuits

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