Hybrid modulator for power converters in parallel topology

Abstract

-This paper presents a new mixed modulator that combines interleaving and spread-spectrum techniques in order to achieve the lowest level of conducted EMI generation. This modulator is addressed to power converters in parallel arrangement. The practical details of the hybrid modulator and controller implementation on a FPGA are explained. The characteristics of such modulator in terms of EMI reduction and converter performance are theoretically explored and experimentally validated in a four channel parallel buck converter operating in closed loop.

Effects of nonidealities in switching frequency modulation techniques: Application to coupled interleaved multicellular parallel converters

“…Notice that each switching pattern has a period equal to the period of the modulation profile, T m , and contains L switching cycles (1). There are several possibilities of combination interleaving and spread spectrum modulation in multiconverter arrangement [4]. The VDFM, which pattern is shown in Fig.…”

“…where f c is the central switching frequency, Δf c is the maximum frequency deviation and H k is the starting time of the k-th switching cycle, that is given by (4).…”

“…Recently, the Variable Delay with switching Frequency Modulation (VDFM) has been presented [1][2][3]. This technique, which combines interleaving with frequency modulation, is specially intended for converters in parallel topology and shows good results in terms of conducted disturbances attenuation [4]. Moreover, VDFM provides a good tradeoff between EMI attenuation and undesirable side effects, such as output voltage ripple increase.…”

EMI Reduction in an Interleaved Buck Converter Through Spread Spectrum Frequency Modulation

“…Originating in the communications sector [15], SSFM purposefully spreads a signal over a larger frequency band. In power converters, this is often done by modulation with a periodic signal, known as periodic SSFM [4], [6], [11], [12].…”

“…However, only [6] explores the application of SSFM to an interleaved converter. Also, there is a lack of comprehensive information regarding the effect of the modulation on efficiency.…”