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Space vector modulation (SVM) is a mature modulation scheme, which is widely used for voltage sourced inverters. In this paper, a flexible online SVM scheme is proposed for a cascaded H-bridge multilevel inverter (CHMI) under short-circuit and open-circuit switch as well as cell failure conditions. The proposed scheme directly calculates all the active redundant switching states and the dwelling duty cycles of the three space vectors enclosing the reference vector for a CHMI such that balanced line-to-line voltages and currents under failure conditions are generated. Accordingly, the resultant switching sequences are determined to meet any specific requirement, e.g., even-order harmonics elimination and minimization of switching losses. Furthermore, in order to reduce voltage stress on the semiconductors under short- and open-circuit switch conditions, an equal power distribution criterion is introduced. The proposed SVM scheme is fast and independent of the number of levels. Experimental results are presented to demonstrate performance and effectiveness of the proposed scheme.

High-voltage manganese-based materials are considered as promising cathode materials for aqueous zinc-ion batteries (AZIBs). Herein, oxygen vacancy-rich K

The power electronic transformer (PET) is a module-cascaded converter with high-frequency-link technology to realize high-power conversion. A typical structure of PET contains a three-phase cascaded H-bridge rectifier in the first stage and several dual active full-bridge (DAB) dc-dc converters in the second stage. Due to dc-link voltage and power unbalancing in the cascaded modules in the first stage, the system may have overvoltage or overcurrent issues. In this paper, based on star-connected cascaded H-bridge (CHB), a zero-sequence voltage injection method is proposed based on the three-phase d-q model to balance dc-link voltage in mutual phase while a hybrid modulation method is proposed to realize dc-link voltage balancing in inner phase. Besides the function of the dc-link voltage balancing, the proposed method is also capable of suppressing the negative sequence and zero sequence components in the system and reducing switching losses.

The isolated bidirectional resonant converter is widely applied for renewable energy battery charger because of its high operating frequency and power density. But traditional LLC converter has many problems in reverse working mode. This paper introduces the CLLC resonant converter into the battery charging and discharging system. The circuit principle and the equivalent model of CLLC resonant converter is analyzed and constructed by FHA method. The CLLC battery charger control strategy is realized by FPGA. Based on the theoretical analysis, the resonant network parameters are designed. Finally, the experimental hardware platform of CLLC resonant converter is designed to verify the feasibility of the overall system.

In order to reduce the number of switches in the three-phase current compensation converter, a compensation scheme of two single-phase half-bridge back-to-back converters is proposed in this paper. In the traditional control, the active current is imbalanced and the reactive power cannot be fully compensated because the angle difference between line voltage and phase current is not considered. In order to solve this problem, a two-phase cross-decoupling control strategy of active and reactive currents is proposed. Firstly, the relation between active and reactive reference compensation currents and load currents is deduced based on the phase angle difference. According to this relation, the active and reactive currents of the single-phase converter are controlled respectively. To suppress the influence of load harmonic current on grid currents, a specific order harmonic control method is proposed. The simulation results show that compared with the traditional control strategy, the proposed control strategy can reduce the imbalance of three-phase current from 25% to 0.5%, increase the PF from 0.962 to 0.999, and compensate the grid harmonic currents.