PHOTOVOLTAIC INVERTER WITH SWINGING LINE FILTER INDUCTORS

摘要

The invention is a high efficiency single-phase or poly-phase DC-to-AC power converter apparatus and power conversion method which includes a line filter inductor or line filter inductors to integrate or filter pulse modulated waveforms into substantially sinusoidal waveforms wherein (i) the line filter inductor or inductors have inductance values that swing substantially from zero current to peak rated current and (ii) a pulse width modulation technique is used that varies both pulse width modulation duty cycles and periods as a function of the predicted instantaneous line filter inductance and the predicted di/dt across the line filter inductor or inductors in order to minimize power converter switching losses while maintaining AC power quality. With the invention, substantial CEC power conversion efficiency enhancements should be achievable and with an overall reduction in power converter parts cost.

主权项

1. A DC-to-AC power converter apparatus comprising a swinging AC line filter inductor, a semiconductor switching matrix and a control circuit wherein;
said DC-to-AC power converter converts power from a coupled DC source over a range of voltages hereafter referred to as the DC input voltage and wherein; said DC-to-AC power converter sources power to a coupled AC load over a range of voltages and range of currents hereafter referred to as the AC output voltage and the AC output current, respectively, and wherein; said DC-to-AC power converter apparatus is specified for operation between a minimum rated AC output current and a peak rated AC output current and wherein; a ripple current is generated by the power converter as an artifact of a switch mode power conversion method for said semiconductor switching matrix and wherein; said swinging AC line filter inductor has a non-linear, current-to-inductance characteristic where the inductance of said swinging AC line filter inductor exhibits more than a 20% decrease in said inductance when operating at said peak rated AC output current relative said inductance when operating at said minimum rated AC output current and wherein; said semiconductor switching matrix comprises at least one semiconductor switch which is driven on for the on-time and driven off for the off-time wherein the on-time plus the off-time is referenced hereafter as the switching period and wherein the on-time divided by the switching period is referenced hereafter as the duty cycle and wherein; said at least one semiconductor switch which is driven on for the on-time and driven off for the off-time is driven under command of said control circuit in response to at least one of said inductance of said swinging AC line filter inductor, said DC input voltage or said AC output current.