Optimum Boost Control of Quasi-Z Source Indirect Matrix Converter

Quasi-Z source indirect matrix converter (QZS-IMC) has been proved to have abilities of voltage boost, current filtering, variable voltage, and variable frequency. The voltage gain of QZS-IMC depends on QZS network shoot-through duty ratio D, rectifier modulation ratio m(i), and inverter modulation ratio m(o). Their multiple combinations are able to achieve the same voltage gain, but determining which is the optimal has not been addressed. In addition, the size of D is associated with the duration of shoot-through events of the QZS network, voltage and current stresses of power devices, and the system power losse. This paper proposes to find the optimal operation curve of D based on the constrained optimization theory. Simulation and experimental results validate theoretical analysis, the proposed optimal control, and the power loss reduction of the QZS-IMC.