A Secondary-Side Semiactive 3-Phase Interleaved Resonant Converter Employing Multimode Modulation Scheme for Fast EV Charger Applications

A secondary-side semiactive three-phase interleaved (SS-SA3PI) resonant converter employing a multimode modulation scheme for fast EV charger applications is proposed. A multimode modulation scheme is used to widen the output voltage range without dynamic switching problems. By using secondary-side semiactive control, the resonant converter does not need to operate in the
f_s
<
f_r
state to achieve boost operation. The minimum switching frequency of the converter is equal to the resonant frequency, which reduces the size of the magnetic components. Thus, the power density of the converter is improved. Compared with the traditional 3-phase interleaved
LLC
converter controlled by PFM, this converter widens the output voltage range without adding any circuit components. This article introduces the control mode, working principle and characteristics of the proposed converter in detail. A 10 kW experimental prototype is built to realize the output voltage of 100–1000V, which verifies the feasibility and effectiveness of the scheme.