Research And Implementation On Control Strategy Of Bridge Modular Switched-capacitor Converter

Switched-capacitor converter is a converter without any magnetic element.With the advantages of low cost,small size,high integration,high efficiency and high integration level,the switched-capacitor converter has been applied in the field of new energy power generation,micro grid,electric cars and so on.However,the ttraditional switched-capacitor circuit has a weak abilitity of output voltage ratio regulation,and often need to cascade the topology circuits to achieve that.To solve above problems,this paper did a research about the control strategy of a bridge modular switched-capacitor converter.Compared with the traditional switched-capacitor circuit,bridge modular switched-capacitor topology features less output voltage ripple,less components cost and convenient voltage extension.This paper presents a new phase-shift control strategy based on bridge modular switched-capacitor topology,which achieves a highly effective conversion of DC-DC and AC-ACThe resonant buck-boost DC-DC converter based on bridge modular switched-capacitor and the strategy have been presented in chapter 2,and the topology,phase-shift strategy are explained at first.On the basis of topology,the working principles of the converter's step-up mode and step-down mode are described in detail,then with the simplified circuit,a specific relation between output voltage and phase shift time was calculated by the state equation.Soft-switching operation is optimized achieved according to a little inductor,and zero voltage switching turn-off(ZVS)and ZVS turn-on is realized for all the switches.The principle and realization condition of ZVS are discussed in the paper.At last,simulations and experiments are did to verify the validity of the theory principles of the converter.The resonant buck-boost DC-DC converter has a modal interchange and adjustable output voltage regulation is achieved by changing the phase-shift time and exchanging the connection ports of inpout power and output load without changing the circuit topology structure,and with the soft-switching operation,the efficiency of the converter is improved further.The resonant buck-boost AC-AC converter based on bridge modular switched-capacitor and the strategy have been presented in chapter 3,and the topology,phase-shift strategy are also explained at first.On the basis of topology,this paper have presented two control strategies.The working principles of the converter at the positive half cycle and the negative half cycle are described in detail,and the switch processes are discussed,then a specific relation between output voltage and phase shift time was calculated by the state equation.At last,simulations and experiments are did to verify the validity of the theory principles of the converter.The resonant buck-boost AC-AC converter also has a modal interchange and adjustable output voltage regulation is achieved by changing the phase-shift time and exchanging the connection ports of inpout power and output load without changing the circuit topology structure,and solves the problem of a safe commutation by providing a continuous flow loop of inductance at the processes of transferring switches.