Research And Implementat On Bi-directinal DC-DC Converter For Hybrid Bus

Hybrid bus has great economic and social value on energy crisis mitigation,energy conservation and new energy industry development and upgrading.Bi-directional DC-DC converter acts as the medium of energy flowing betweenstorage battery and motor inverter bus, which as one of three major research topicsin hybrid field. It is also an important part of improving the efficiency.In light of the objective needs and requriements of hybrid bus, this paper hasselected a high-power high-efficiency half-bridge Buck/Boost converter structureand designed an improvement on the basis of the state-space averagin modelingmethod, which is suitable for bi-directional DC-DC converter. This method coversforward Boost working and reverse Buck working process, which can take the smallsignal analysis of two states at the same time.The motor inverter bus side focuses on it’s voltage and the storage batteryfocuses on it’s current. For this feature, a double-loop control strategy is designed inthis paper, in which the voltage and current are double-ended controlled. the voltageloop controls the system’s stability and the current improves it’s dynamic response.In order to solve the bus voltage fluctuations dued to the load characteristicmutations and input voltage disturbance, an power feed and input voltagecompensation strategy are used. This measure forecasts the trend of output powerand improves the ability to adjust the system load.The DsPIC30F6010A MCU is used to realize the design of double-loop controlsystem, the software and hardware protection measures are used to guarantee thesecurity of the system. Variable parameter PID algorithm was used in double-loopcontrol system. This control strategy can achieve best control effects according tothe needs of the system.The entire control system platform has been built using the simulink, whichverified the correctness of the control scheme and the feasibility of the feed forwardcontrol strategy. In the same time the low-power experimental platform ofbi-directional DC-DC converters has been built, through a series of experimentsverified the feasibility of its control scheme and the accuracy of the parametercalculation and design. The overrall efficency can reach92%through the Efficiencyunder the experimental analysis in the pros and cons working condition.