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In this study, a modified efficient step-up boost converter is proposed. The proposed structure employs coupled-inductor and super-lift techniques to achieve high voltage gain. The super-lift stage absorbs the available energy in the leakage inductance of the coupled inductor, clamps the off-state voltage of the main switch, and reaches a moderate voltage gain. Moreover, the coupled-inductor technique offers high voltage gain, low off-state voltage for the main switch, and alleviates the reverse-recovery problem of the output diode. Hence, using these two techniques, the proposed converter achieves high step-up voltage gain and eliminates the drawbacks of the conventional boost converter. The proposed converter is analysed in details and a hardware prototype with the input voltage of 15 V, output voltage of 200 V and the nominal power of 100 W is utilised for the experimental investigation.

The interleaving technique is a well-known technique applied in high power applications to share the output power between two modules while decreasing the input current and output current ripple. Moreover, zero current switching technique can be used in order to reduce the switching losses and increase the power density. Zero-currentswitching (ZCS) condition as the soft-switching technique is usually applied for IGBT switches in order to eliminate tailing current losses. In this study, a new ZCS pulse-width-modulation (ZCS-PWM) interleaved boost converter is proposed which applies only one auxiliary switch. In the proposed converter ZCS condition is provided for main switches while the auxiliary switch is also soft switched. The principle of operation, performance analysis, and design method of the proposed converter are presented in details. Finally, the theoretical results are verified by experimental results.

In this study, a new zero‐voltage switching (ZVS) output inductor‐less bidirectional forward (OILBF) converter is presented. The OILBF has two diodes less than the conventional forward converter and is convenient for low‐power bidirectional applications. Moreover, the OILBF converter uses the leakage inductance of transformer as the forward inductor. In the proposed OILBF, two capacitors paralleled with main switches realise ZVS conditions for main switches in both directions without any auxiliary switches. Also, the reset of the converter transformer is done without any additional circuit. The proposed converter structure due to employing simultaneously OILBF topology with the simple auxiliary soft‐switching circuit is simple and low cost. The ZVS soft‐switching range is from light load to full load which enhances the converter efficiency. Phase shift is applied with the proposed converter. The proposed converter is completely analysed and its design approach is considered. Finally, an experimental prototype is implemented to verify theoretical results.

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A new single switch ZVS forward converter with a wide soft-switching range is proposed here. Compared to the conventional forward converter, the proposed converter uses fewer components and operates under ZVS soft switching. A capacitor, along with both the leakage and magnetizing inductances, provides ZVS soft switching and transformer core reset. To regulate the output voltage against the input voltage and the load variations, an inductor is added to the converter. The inductance of the additional inductor varies with the direct current (DC) of the DC bias winding to regulate the output voltage. Therefore, the duty cycle and the switching frequency are constant in the proposed converter. With the constant duty cycle and the constant switching frequency, the wide ZVS soft switching is achieved. The proposed converter is completely analysed theoretically. The finite element analysis is used to design the additional inductor. By designing an experimental prototype, the theoretical analysis is justified using the experimental results.

-Electro-Mechanical Batteries have important advantages compared with chemical batteries, especially in Low Earth Orbit satellites applications. High speed, slotless, external rotor, brushless DC machines are proposed and used in these systems as Motor/Generator. A simplified analytic design method is given for this type of machines and, the optimization of machine in order to have maximum efficiency and minimum volume and weight are given in this paper. Particle swarm optimization (PSO) is used as the optimization algorithm and the finite element-based simulations are used to confirm the design and optimization process and show less than 6% error in parametric design.