A Novel Interleaved Parallel Quasi-Z Source DC Converter And Its Control Research

With the increasingly severe environmental and energy shortages,the development of new energy sources such as photovoltaic power generation and fuel cells has become the focus of attention,and how to convert the lower front-end output voltage into a new energy generation system such as photovoltaic power generation and fuel cells.High grid power generation grade voltage has become an important research direction in today's new generation energy generation system.This paper innovatively links a quasi-Z source conversion topology with staggered parallel technology,and proposes a new type of interleaved parallel quasi-Z source DC converter.Based on the analysis of the traditional boost topology,this paper introduces a quasi-Z source conversion topology.By adding an impedance network composed of switched capacitors,switching inductors and diodes,the conversion topology can be more ideal at lower duty cycles.Voltage boost capability and interleaved parallel technology applied to a quasi-Z source conversion topology.Based on the high boost ratio,the new conversion topology also has the advantages of reduced input and output current ripple and reduced voltage and current stress of the power device.It is suitable for a new power generation system that requires low voltage and high current input and high voltage output.In this paper,the working mode and process of Z-source conversion topology are analyzed theoretically,and how the new staggered parallel quasi-Z source DC converter is derived.The voltage-current relationship of each part in the new conversion topology is analyzed in detail when the operating current of the circuit is continuous.The boost ratio of the circuit is derived by using the second-order equilibrium theorem of the capacitor and the volt-second equilibrium theorem of the inductor to analyze different parasitic The effect of parameters on the performance of the new conversion topology.The state average method is used to establish a small signal model for the new conversion topology,and the transfer function of the input and output signals of each part under the influence of parasitic parameters is derived.At the same time,the PID compensation network is designed to realize the closed-loop control of the whole.Improved dynamic adjustment characteristics.Draw the hardware schematic of the new conversion topology and design the PCB to illustrate the working principle of each part of the circuit.The DSP28335 is used as the system main control chip to complete the functions of sampling,closed-loop,and generating PWM signals.The sub-module introduces the software design.The Saber software is used to simulate the voltage and current waveforms of the key components in the new conversion topology,and a 38 W experimental prototype is built in the laboratory for verification.The experimental results are consistent with the simulation phenomenon and theoretical analysis.The feasibility and effectiveness of the new interleaved quasi-Z source DC converter proposed in this paper are proved.It provides a reference for the interleaving parallelization of other Z-source conversion topologies in the future.