Low-frequency Wireless Charging Technology For Mobile Robot

Wireless charging of intelligent robot plays a great role in the intelligence of robot, which can ensure that the robots do all the work on their own.In this paper, a low-power and low frequency wireless charging system is designed, which aim at the small and medium sized mobile robot. The frequency of the system is 10 k Hz, and the transmission power is over one hundred. The transmission distance is 30 mm, and the coil size is within 100 mm * 100 mm, the transmitter and receiver circuit boards are within 100 mm * 100 mm at the same time. The efficiency can reach above 80%. This system is completely suitable for the use of robots on size, as it does not take up too much internal space and low frequency, low radiation and price, which could facilitate the commercialization of development.This paper analyses and compares the LC series system and LCL system, the situations of the LCL system with different inductance and capacitance. It obtains the circuit coupling equations of the two different systems through research of theory and deduced formulas, and gets the theoretical relationships between the voltage and current of the two kinds of circuits. These theories play a guiding role in the actual system design.The paper determines the whole bridge inverter circuit and device parameter values of withstand voltage and current through the simulation and the basic experiment which can verify the range of the voltage and current. It controls the output of inverter circuit with the built-in PWM signal transmitter, makes simulation of the coupling coil with different number of turns, distance and displacement and obtains the actual parameters of the coupling coil. It designs BUCK circuit to achieve a constant current charging on the output, makes simulation and analysis on the characteristics of BUCK circuit of the wireless power transmission receiver, and verifies the feasibility of the scheme throug h the experiment, through using the control chip STM32 to complete the closed loop system, which main part is PI adjustment and could detect the charging current value to adjust the duty ratio of BUCK circuit, using a constant current to charge the battery.This paper analyzes system characteristics in different displacement, transmission distance, and duty cycle of BUCK circuit. It conducts the simulation and experiment for these three parameters, and designs the closed-loop control strategy of the system, which ensures that the rise of bus voltage has good robustness when the closed-loop program displaces in the system.