Research On Piezoelectric Energy Harvesting System With Synchronized Switch Technology

With the development of science and technology,more and more attention has been paid to the power supply of electronic equipment.Traditional batteries with large volume and poor endurance have been unable to meet the requirements.Therefore,scholars start to focus on the renewable energy in the surrounding environment.Piezoelectric energy harvesting is widely used because of its high energy density,easy realization and small size.In order to improve the efficiency of energy harvesting,scholars continue to optimize the piezoelectric energy harvesting technology,and the synchronized switch technology is proposed.Synchronized switch technology requires high precision of the control signal.If the signal delay is large,it will cause large energy loss.The existing piezoelectric energy harvesting circuit based on synchronized switch technology is complicated,difficult to implement and not accurate enough to control the synchronous switches.In view of above deficiencies,a novel zero-crossing detection method is proposed to realize the phase alignment between the zero-crossing detection signal and the current signal and improve the precision of the zero-crossing detection circuit.Based on this method,two novel piezoelectric energy harvesting systems is proposed,simulated by Multisim software and tested by test platform.Under the open circuit voltage of 6.5 V and the load resistance of 10 kΩ,the output voltage is 4.24 V.And the output power is 1.8 mW,which is four times of traditional synchronized switch harvesting on capacitors circuit.A novel piezoelectric energy system is proposed based on synchronized switch harvesting on capacitor circuit.In this system,sampling resistance is added to accurately sample the working state.And the pulse width of the synchronous control signals is adaptively adjusted according to the voltage flipping state.This system can improve the voltage flipping efficiency and output power.Based on the synchronized switch harvesting on inductor circuit,a synchronized alternating switch harvesting on inductor system is proposed.This system has a simple circuit structure,and can accurately control the synchronous switches.Therefore,this system can reduce the circuit loss and increase the output power.When the open-circuit voltage is 6 V and the load resistance is 10kΩ,the output voltage is 2.166 V.And the output power is 0.469 mW,which is 1.42times of conventional synchronized switch harvesting on inductance circuit.In a word,the two novel piezoelectric energy harvesting systems based on synchronized switch technology proposed can achieve accurate zero crossing detection and synchronous switch control,with lower circuit loss and significantly improved output power.