Research On Space Vector Modulation Strategy Of Automotive Current Source Trans-Z Source Inverter

The Z-source inverter not only eliminates the drawbacks of the traditional inverter,but also enables the circuit to have a range of buck-boost capability.The current source Trans quasi Z source inverter(CF-Trans-qZSI)not only has a buck-boost capability compared to the conventional current-source Z-source inverter by introducing a Trans-Z-network into a conventional current source inverter,and by using a coupled inductor instead of two separate inductive components in the Z network,the output voltage can be further increased while reducing the number of components.Compared with voltage-type Z-source inverters,CF-Trans-qZSI can allow allow energy feedback without adding additional switches,which is more in line with the requirements of electric vehicles for drive systems,so it has great applications in electric vehicle drive systems.Currently commonly used modulation methods can be divided into PWM modulation and SVPWM modulation.The traditional PWM modulation method is simple to implement,but the voltage utilization rate is low;the SVPWM modulation method is more complicated to implement,but the voltage utilization is higher and the output waveform quality is better.This paper first introduces the SVPWM modulation strategy for CF-Trans-qZSI in detail,but SVPWM modulation usually brings higher switching times,which not only increases the energy loss,but also the excessive junction temperature caused by the loss will also affect Device reliability.In order to reduce the number of switching operations,this paper proposes a SVPWAM modulation method,which reduces the number of changes in the working state of the circuit by reducing the action time of the traditional zero v ector to the effective vector according to a certain mathematical logic,thereby reducing the number of switching operations.At the same time,the switch series is optimized,so that the insertion of the open zero vector does not increase the number of ad ditional switching operations;by selecting the insertion position of the open state,the inductance ripple is reduced,thereby reducing the inductance.Finally,by adjusting the open circuit duty cycle,the input bus current waveform is changed to improve the quality of the output waveform.After that,the switching times and on-duty ratios of the switching devices under two modulation strategies are deduced in detail,and the junction temperature calculation model and the loss calculation model under two modulation strategies is established.Finally,a joint simulation model of MATLAB/Simulink and PLECS was built.The control circuit is built in the Simulink environment,and the loss model of the main circuit model and the switching device is built in the PLECS environment.The device loss and temperature rise before and after the open circuit state are simulated under two modulation strategies.The superiority of the proposed strategy is verified by simulation.