Hybrid cascaded thirteen level H-bridge modulation strategy and power equalization method
When the DC voltage source ratio is 1∶1∶2∶2,the hybrid inverter adopts the traditional hybrid modulation strategy,which has the disadvantage of unbalanced power of two high voltage and low voltage respectively.To solve the above problems,this paper proposes an improved modulation strategy,which re-alizes the power balance of the high voltage unit by exchanging the pulses of the high voltage unit with 1/4 cycle.On this basis,the triangular carrier is reconstructed to make the switching loss of the two low voltage H-bridge units the same.It ensures the power balance of the high and low voltage two units,and the power switches of the high voltage and low voltage parts work at the basic frequency and high frequency respec-tively,reducing the loss and having good harmonic characteristics.Simulation and experimental studies have proved the accuracy and practicality of the above theoretical analysis.