Comprehensive Optimization Design Based On Switching Boost Inverter

Solar photovoltaic power generation has become an important research direction in the field of renewable energy,in which photovoltaic inverter as one of the most critical equipment has become the focus of attention.Although the traditional inverters,Z/Quasi-Z source inverters and switch-boosted inverters have been innovated continuously,they still have their own limitations.By contrast,the new switching booster inverter can achieve the same voltage gain as the z-source inverter,and it also has the advantages of simpler front-stage circuit,avoiding dead zone time and so on.It will become an important candidate for application in various fields in the future.However,in the practical application of the new switchgear inverter,there are some problems such as high bus voltage double frequency and common mode voltage,which lead to switching loss,damage to power quality and leakage current.Therefore,it is of great significance to optimize the design of the new type of switch booster inverter.In this paper,a “PI+PR” collaborative control method was proposed to solve the problem of double frequency of bus voltage in single-phase new switching inverter.First of all,the derivation and analysis of the new booster inverter switch busbar voltage causes of the double frequency,and optimal parameter design method of simulation was used to study the level before the circuit inductance,capacitance and resistance of the output side of busbar voltage double frequency,the influence of the new switch booster single-phase inverter under the condition of multiple sets of parameters of busbar voltage frequency double size.Then,the principle of PI and PR control methods,the transfer function and the static and dynamic control process of DC side voltage and AC current were introduced.Finally,under the condition of multiple circuit parameters,the simulation study proves that the closed-loop control of "PI+PR" has obvious suppression effect on the bus voltage double frequency of the new type of switch booster inverter,and the bus voltage double frequency amplitude decreases significantly compared with the open-loop condition.In order to solve the common mode voltage problem of the new type of switchboost inverter,an odd-vector pulse width modulation strategy(OPWM)was proposed to suppress the system common mode voltage.Firstly,the corresponding relation between the voltage vector and the switching state of the three-phase inverter bridge in space vector modulation was introduced,and then the common mode voltage caused by each voltage vector in the new switching inverter was calculated and analyzed,and it was proved that the common mode voltage could be suppressed by adopting the strategy of OPWM.Then,the selection principle of voltage vector in space vector pulse width modulation strategy(SVPWM)and OPWM,the synthesis method of target vector,the action time of voltage vector and the action sequence of switch sequence were introduced respectively.Finally,simulation analysis shows that the amplitude of common mode voltage caused by OPWM modulation strategy was 1/3upn,which was 2/3 lower than that caused by SVPWM modulation strategy.Finally,the experimental platform of a new type of switching and boosting inverter was built,which verifies that the OPWM modulation strategy could effectively suppress the system's common mode voltage.