The cascaded multilevel converter is widely employed in medium/high voltage and high power electronic applications for its small harmonic components of output voltage and convenient modulation. In this paper

the operation principle of a T-type H-bridge topology is investigated in detail

and a carrier phase shifted pulse width modulation(CPS-PWM)based control method for this topology is proposed. By taking a virtual five-level waveform achieved with uni-polar double frequency CPS-PWM as the output objective

PWM signals of the T-type H-bridge can be obtained by reverse derivation according to its switching modes. Besides

a control method for T-type H-bridge based cascaded multilevel converter is introduced. A single-phase T-type H-bridge cascaded static synchronous compensator(STATCOM)prototype is built

and the DC-link voltage balancing control scheme is analyzed. Finally

the correctness and feasibility of the proposed modulation method and control strategy for T-type H-bridge based cascaded multilevel converter is verified by simulation and experimental results. This work is supported by National Natural Science Foundation of China(No. 51177147)and Zhejiang Key Science and Technology Innovation Group Program(No. 2010R50021).