Patent ID: 8982587
Filing Date: 2015-03-17
Classification: H02M

Abstract:
1. A ripple compensation apparatus, comprising: a ripple detection unit to detect a ripple on a dual DC bus; a waveform generation unit to generate a modulated waveform based on a base waveform and the detected ripple; a multi-phase control signal generation unit configured to receive the modulated waveform and to generate at least one pulse width modulated control signal based on the modulated waveform; and a multi-level power inverter configured to receive as inputs the dual DC bus and the at least one pulse modulated control signal and to output a multi-phase AC voltage based on the dual DC bus and the at least one pulse modulated control signal; wherein the multi-level power inverter includes a plurality of sets of transistors, each set corresponding to a separate one of a plurality of phases of the multi-phase AC voltage, and the at least one pulse modulated control signal includes a plurality of sets of pulse modulated control signals to control a respective one of the plurality of sets of transistors and wherein each one of the plurality of sets of transistors includes first and second transistors connected in series source-to-drain, and third and fourth transistors connected in series source-to-drain, the second and third transistors being connected in series source-to-drain, an output voltage line connected between the second and third transistors, a first DC voltage line of the dual DC bus connected to the first transistor, a second DC voltage line of the dual DC bus connected to the fourth transistor, and a third DC voltage line of the dual DC bus connected between the first and second transistors and between the third and fourth transistors.