DC-AC inverter with soft switching

摘要

Provided are single phase and multiple phase DC-AC inverters with soft switching, and related methods and uses. The DC-AC inverters comprise at least one voltage source inverter circuit or at least one current source inverter circuit having a DC input and an AC output including a first component at a fundamental frequency and a ripple component at a frequency higher than the fundamental frequency; wherein the ripple component is of a sufficient magnitude that the voltage source inverter circuit output current reverses polarity and allows the at least one inverter circuit to operate with zero voltage switching; or wherein the ripple component is of a sufficient magnitude that the current source inverter circuit output voltage reverses polarity and allows the at least one inverter circuit to operate with zero current switching. The circuits and methods may be used with grid-connected renewable energy sources.

主权项

1. A DC-AC inverter, comprising:
a voltage source inverter circuit having a DC input and an AC output including a first component at a fundamental frequency and a ripple component at a frequency higher than the fundamental frequency; a passive element connected to the AC output of the voltage source inverter circuit; wherein a value of the passive element is selected to maintain the ripple component of the AC output at a sufficient magnitude so that a voltage source inverter circuit output current reverses polarity and the voltage source inverter circuit operates with zero voltage switching; wherein the DC-AC inverter includes a cancellation circuit comprising two or more voltage source inverter circuits, each voltage source inverter circuit providing an AC output including a first component at a fundamental frequency and a ripple component at a frequency higher than the fundamental frequency; wherein each voltage source inverter circuit operates with zero voltage switching; wherein the AC outputs of each voltage source inverter circuit are connected in parallel to produce a total output current, such that the ripple components of the AC outputs are substantially cancelled to reduce or eliminate the ripple component in the total output current delivered to a load; and wherein the AC outputs of the voltage source inverter circuits are phase shifted by amounts selected to substantially cancel the ripple components and reduce or eliminate the ripple components in the total output current delivered to the load.