METHOD AND APPARATUS OF A UNIFIED CONTROL SOLUTION FOR BRIDGELESS POWER FACTOR CONTROLLERS AND GRID CONNECTED INVERTERS

摘要

A unified control solution for both bridgeless power factor controllers and grid connected inverters is disclosed. Conventionally, the bridgeless power factor controllers and the grid connected inverters are controlled with different approaches. In the present invention, it is disclosed that the two kinds of applications can be controlled with one unified approach. With the disclosed method, one single integrated circuit can be made and be used in both applications. Firstly, a sample based controller is disclosed to derive the ac current reference from the ac voltage and the dc voltage. The ac current reference is forced to be proportional to the ac voltage. The proportion coefficient is derived from the dc voltage in such a way to keep the dc voltage constant. Furthermore, the coefficient is updated only once every half ac line cycle. So as long as the ac current follows the current reference, the dc voltage will be regulated to a constant, and the ac current will be pure sinusoidal. Secondly, a new current mode switching pattern is disclosed based on an improved hysteretic switching pattern. The disclosed switching pattern minimizes the number of switching event and removes the deadtime requirement without the risk of shoot through.