Average current mode control of series-switched post-regulators used in power factor correctors

The application of the average current mode control (ACMC) to a new type of very efficient post-regulator is studied in this paper. This post-regulator, called the series-switched post-regulator (SSR), has been recently proposed to improve the dynamic response of power factor correctors (PFC). The series-switching post-regulator exhibits very high efficiency due to the fact that only a part of the total power undergoes a power conversion process. Using ACMC, the bandwidth of the post-regulator increases in relation to the one obtained when a conventional voltage-mode control (with or without feedforward) is used. As a result, the attenuation of the input voltage ripple (100-120 Hz) increases and, therefore, a lower bulk capacitor can be used to obtain a very low voltage ripple at the output, which is very important when a battery is connected at the output. This is very common in distributed power supply systems