Research On High-gain Sparse Three-level Indirect Matrix Converter

Indirect matrix converter（Matrix Converter,IMC）is a kind of "green" AC-AC inverter,which is often used in motor drive,electric vehicle,railway transportation,new energy industry and other occasions.The Three Level Indirect Matrix Converter（TLIMC）,which combines three-level technology and IMC technology,not only takes into account the advantages of traditional IMC,but also improves the output waveform quality,and the characteristics of low voltage stress of the switch tube are also It is more suitable for high voltage and high power applications.However,the maximum transmission ratio of the indirect matrix converter is only 0.866,which seriously affects its application range in the industrial environment.Therefore,this paper proposes a Dual-Transquasi Z-source Three Level Indirect Matrix Converter（DTrans-q Zs TLIMC）.In terms of topology,in order to improve the voltage gain of the indirect matrix converter,a dual Trans-quasi-Z source network is proposed and introduced into the intermediate link between the rectifier stage and the inverter stage of the three-level indirect matrix converter.Aiming at the problem that the traditional three-level indirect matrix converter uses the LC filter as the neutral point of the inverter stage,the voltage is unstable,and the neutral point is connected to the capacitor neutral point of the dual Trans-quasi-Z source network,which improves the performance of the inverter.level voltage stability.At the same time,in order to reduce the number of power components of the three-level indirect matrix converter,a three-level inverter stage structure composed of 10 power switches is selected.Since the output voltage of the rectifier stage of the indirect matrix converter changes in real time,the voltage ripple will affect the output voltage of the Z source network.Therefore,a mathematical model of the dual Trans-quasi-Z source network is established,and the through state and the non-through state are listed.The state-space equation at,introduces the through duty cycle to obtain the dynamic equation of the state-space average model,analyzes its steady-state operating point and adds small-signal disturbances,performs Laplace transform on the smallsignal model,and analyzes the capacitance in the s-domain The amplitude-frequency characteristics of the component transfer function are analyzed,the influence of the output voltage of the rectifier stage on the operating characteristics of the dual Trans-quasi-Z source network is analyzed,and the maximum voltage transfer ratio of the dual Trans-quasi-Z source three-level indirect matrix converter is deduced.indirect matrix converter is deduced.In terms of modulation strategy,since the SVPWM control strategy involves more trigonometric function calculations,it will bring pressure to the hardware calculation.Therefore,based on the space vector pulse width modulation（SVPWM）strategy,this paper proposes a three-level suitable for dual Trans-quasi-Z sources.The carrier pulse width modulation（CBPWM）strategy of the indirect matrix converter firstly optimizes the switching action sequence according to the SVPWM strategy and the introduction of the straight-through link.The switching moment of each power switch and the corresponding duty cycle are derived.In order to match the switching frequency of the rectifier stage and the inverter stage to make them unified,a triangular wave with a timevarying slope is used,and the signal of the line voltage switching of the rectifier stage is obtained through the peak value,and the duty cycle of the inverter stage is substituted into the time-varying slope of the triangle wave.The carrier is used to derive the modulated wave,and the modulated wave is compared with the carrier to obtain the driving signals of each power switch.By building a simulation model in the Matlab/Simulink platform,the input voltage and current are in the same phase from the waveform,that is,the unit power operation.Finally,the topology of the dual Trans-quasi-Z source three-level indirect matrix converter is built in the hardware-in-the-loop platform and experiments are carried out to verify the correctness of the selected topology and modulation strategy.