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This paper proposes a generalized formulation for selective harmonic elimination pulse-width modulation (SHE-PWM) control suitable for high-voltage high-power cascaded multilevel voltage source converters (VSC) with both equal and nonequal dc sources used in constant frequency utility applications. This formulation offers more degrees of freedom for specifying the cost function without any physical changes to the converter circuit, as compared to conventional stepped waveform technique, and hence the performance of the converter is greatly enhanced. The paper utilizes the merits of the hybrid real coded genetic algorithm (HRCGA) in finding the optimal solution to the nonlinear equation system with fast and guaranteed convergence. It is confirmed that multiple independent sets of solutions exist. Different operating points for both five-and seven-level converters including singleand three-phase patterns are documented. Selected experimental results are reported to verify and validate the theoretical and simulation findings.Index Terms-Cascaded multilevel converter, hybrid genetic algorithm, pulse-width modulation (PWM), selective harmonic elimination.

A five-level symmetrically defined multilevel selective harmonic elimination pulsewidth modulation (MSHE-PWM) strategy is reported in this paper. It is mathematically expressed using Fourier-based equations on a line-to-neutral basis. An equal number of switching transitions when compared against the well-known multicarrier phase-shifted sinusoidal PWM (MPS-SPWM) technique is investigated. For this paper, it is assumed that the four triangular carriers of the MPS-SPWM method have nine per unit frequency resulting in seventeen switching transitions for every quarter period. For the proposed MSHE-PWM method, this allows control of sixteen harmonics and the fundamental. It is confirmed that the proposed MSHE-PWM offers significantly higher converter bandwidth in the standard range of the modulation indices. Moreover, when the bandwidth is reduced to be equal with the one offered with the MPS-PWM, the modulation index can be increased resulting in a higher gain and at a reduced switching frequency overall. Selected solutions for the switching transitions are presented and verified experimentally in order to confirm the effectiveness of the proposed technique. Index Terms-Multilevel Converter, optimization, phase-shifted sinusoidal pulsewidth modulation (PS-PWM), pulsewidth modulation (PWM), selective harmonic elimination (SHE).

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This paper presents a neutral point voltage control strategy for the three-level active neutral point clamped (ANPC) converter using selective harmonic elimination pulsewidth modulation (SHE-PWM). The control strategy introduces a small change in the switching angles, which varies the duty cycle of the zero-level switching state, controls the neutral point current and, therefore, the neutral point voltage. The decision to vary a given switching angle takes into account the polarity of the output currents and the voltage across the lower dc-link capacitor. The effectiveness of the proposed strategy is verified through extensive simulation studies and experimentally validated using a low power laboratory prototype. Index Terms-Active neutral point clamped converter (ANPC), neutral point voltage control, pulse-width modulation (PWM), selective harmonic elimination (SHE).

This paper presents a novel three-phase DC-link multilevel inverter topology with reduced number of input DC power supplies. The proposed inverter consists of series-connected half-bridge modules to generate the multilevel waveform and a simple H-bridge module, acting as a polarity generator. The inverter output voltage is transferred to the load through a threephase transformer, which facilitates a galvanic isolation between the inverter and the load. The proposed topology features many advantages when compared with the conventional multilevel inverters proposed in the literatures. These features include scalability, simple control, reduced number of DC voltage sources and less devices count. A simple sinusoidal pulse-width modulation technique is employed to control the proposed inverter. The performance of the inverter is evaluated under different loading conditions and a comparison with some existing topologies is also presented. The feasibility and effectiveness of the proposed inverter are confirmed through simulation and experimental studies using a scaled down low-voltage laboratory prototype.

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Multiple output chargers have widely been adopted in various electronic devices due to their benefit concerning cost, power density, and space for installation. On the contrary, Inductive Power Transfer (IPT) has been applied increasingly in electric vehicles (EV) since it is safer and more convenient as compared to conductive chargers. However, researches on multiple output chargers using IPT system for EV charging applications are rarely presented. This paper proposes a new concept of a multiple output IPT charger, which can charge several output batteries independently and simultaneously by adopting only one full bridge inverter at the primary side combining with multiple transmitters. Two possible IPT-coil structures are analyzed, and the minimum distance between each channel's coils is determined to neglect the cross-coupling between them. Two options are proposed to attain Zero Phase Angle (ZPA) condition for primary inverter of the proposed system. First option is to operate the compensation tanks of every output channel at exact ZPA frequencies. The other option is to let one channel working in inductive region of its input impedance and other channel working in capacitive region. By adopting an appropriate design, the reactive powers of these tanks can be nearly cancelled each other and the phase of inverter current can be nearly in-phase with the input voltage as a result. Two proposed options are compared to give recommendation whether option 1 or 2 should be selected according to various of application's requirements. To simplify control complexity, IPT output current sources topologies are selected, compared and analyzed to construct the proposed multiple output system in both above options. Double-sided LCC and Series-Parallel (SP) topologies are adopted to demonstrate the proposed idea for Option 1 and 2, respectively. In order to verify feasibility and validity of the proposed method, experimental results of two output channels with the total output power of 1.5 kW are provided. Experimental results indicate that the ZPA is achieved for primary inverter with both of two above options even under the different load conditions. Some comparisons between the conventional and the proposed IPT charging structure in terms of cost, reliability and complexity are included in discussion session. Index Terms-Inductive power transfer; multiple output charger; IPT compensation topologies, wireless EV charging.