Research On Three-Phase Buck-Boost Interleaved Parallel Bidirectional DC/DC Converter

The demand for high power bidirectional DC/DC Converter in photovoltaic power generation, electric vehicles and other occasions is growing more and more faster. The traditional topology of the bidirectional DC/DC generally exists the problem of large voltage,current stress and slow response speed in high power situations. The interleaved bidirectional DC/DC, which has high output power, good power quality and good dynamic performance, has been widely used in high power applications.A three phase interleaved BUCK-BOOST DC/DC converter was designed in this paper, this converter solve the problem of unbalanced current in each phase. The hardware and control program of three phase interleaved parallel DC/DC BUCK-BOOST converter are designed. The main contents of this paper are as follows:Current-sharing Control Strategy with a duty cycle controller is designed in this paper, which is based on the control of the output line of the traditional double loop control. The simulation experiment shows that the control method and the traditional current loop independent control method can achieve the same flow control effect, which can achieve the same as 5%.The prototype of BUCK-BOOST is designed, and the prototype design includes the design of the main circuit and control circuit. The prototype uses the digital design method, the core of the system the is microprocessor. The controller is designed by using the PI control strategy of the inner loop of the voltage outer loop. The the duty cycle controller is added and the voltage closed-loop control and current-sharing control are realized.Under the condition of room temperature, the control effect of the function and the flow control algorithm of the prototype is tested. The experimental results show that the prototype can be able to achieve the expected results of current-sharing control and closed-loop control.