Direct power control of single-phase three-level rectifiers without phase locked loop

In order to implement active and reactive power decoupling control of single-phase three-level pulse rectifiers without phase-locked loop (PLL), first of all, a single-phase three-level pulse rectifier was modeled with mathematic expressions. Secondly, according to the definition of active and reactive power, a single phase instantaneous power calculation method without PLL was proposed, and the detailed deduction process was shown. On the basis of this, a frequency compensation method was proposed to realize a non-synchronous rotating coordinate system without PLL coordinate transformation. Then, the combination control scheme of the PI control with power feedforward decoupling and a single-phase three-level space vector modulation (SVPWM) embedded neutral voltage balance were adopted for a single-phase three-level pulse rectifier. Finally, the proposed direct power control and SVPWM algorithm without PLL were verified in computer simulations and hardware-in-the-loop experimental tests, the simulation and experiment results have verified the correctness and validity of the algorithm. © 2015 Chin. Soc. for Elec. Eng..