On the basis of the classical Z-source inverter, this paper presents a developed impedance-type power inverter that is termed the switched inductor (SL) Z-source inverter. To enlarge voltage adjustability, the proposed inverter employs a unique SL impedance network to couple the main circuit and the power source. Compared with the classical Z-source inverter, the proposed inverter increases the voltage boost inversion ability significantly. Only a very short shoot-through zero state is required to obtain high voltage conversion ratios, which is beneficial for improving the output power quality of the main circuit. In addition, the voltage buck inversion ability is also provided in the proposed inverter for those applications that need low ac voltages. Similar to the classical Z-source inverter, the proposed concepts of SL Z-source inverter can be applied to various applications of dc-ac, ac-ac, dc-dc, and ac-dc power conversion. A detailed topology analysis and a generalized discussion are given. Both simulation and experimental results verify the analytical results.

Traditional voltage-source inverter is limited by its only voltage step-down operation, while current-source inverter is limited by its only current step-down mode. In order to add an extra boosting flexibility while keeping the number of active semiconductors unchanged, voltage-type and current-type Z-source inverters were earlier proposed. These new classes of inverters are generally more robust and less sensitive to electromagnetic noises. However, their boosting capabilities are somehow compromised by high component stresses and poorer spectral performances caused by low modulation ratios. Their boosting gains are, therefore, limited in practice. To overcome these shortcomings, the generalized switched-inductor and switched-capacitor Z-source inverters are proposed, whose extra boosting abilities and other advantages have already been verified in simulation and experiment.

The voltage-lift technique is an effective method that could be applied in electronic circuit design. A set of positive output DC–DC converters applying series SEPIC implementing voltage-lift techniques is introduced. Compared with the prototype of the SEPIC converter, these converters can perform positive to positive DC–DC voltage increasing conversion with higher voltage transfer gains. They are different from other existing DC–DC step-up converters and possess obvious advantages, mainly including fewer switches, clear conversion processes and a high output voltage with small ripples. Since the proposed converters avoid using transformers and cascade connection, relative simple structures are beneficial to potential practical applications in future. A detailed theoretical analysis for continuous and discontinuous conduction modes is given. Both simulation and experimental results are provided to verify the main characteristics.

Inverters with high-output voltage gain usually face the problem of high-input current flowing through their components. The problem might further be exaggerated if the inverters use high-frequency magnetic devices like transformers or coupled inductors. Leakage inductances of these devices must strictly be small to prevent overvoltages caused by switching of their winding currents. To avoid these related problems, cascaded trans-Z-source inverters are proposed. They use multiple magnetic cells in an alternately cascading pattern rather than a single magnetic cell with large turns ratio. Simulation and experimental results have shown that the multicell inverters can produce the same high-voltage gain, while keeping currents and voltages of the components low. The inverters can also step down their output voltages like a traditional voltage-source inverter without compromising waveform quality.

The concepts of voltage-lift-type switched-inductor cells have been proposed. The proposed circuit cells can be used to improve the boost abilities of those traditional transformerless DC–DC converters. More importantly, they can be fabricated as integrated cells and inserted into all the basic converters easily. All newly developed converters are applicable to those situations where high voltage transfer gains are required. The four-order Luo converter is taken as an example and integrated with the proposed switched-inductor cells. Both continuous conduction mode and discontinuous conduction mode operations are analysed. All theoretical results are supported by the corresponding simulation and experimental results.

Unlike a land-based standalone microgrid, a shipboard microgrid of an all-electric ship (AES) needs to shut down generators during berthing at the port for examination and maintenance. Therefore, the cost of onshore power plays an important role in an economic operation for AESs. In order to fully exploit its potential, a two-stage joint scheduling model is proposed to optimally coordinate the power generation and voyage scheduling of an AES. Different from previous studies that only consider the operation cost of the ship itself, a novel coordinated framework is developed in this article to address the shore-side electricity price variations on the ship navigation route. A deep learning-based forecasting method is utilized to predict the electricity price in various harbors for ship operators. Then, a hybrid optimization algorithm is designed to solve the proposed multiobjective joint scheduling problem. A navigation route in Australia is adopted for case studies and simulation results demonstrate the high energy utilization efficiency of the proposed algorithm and the necessity of on-shore power influence on the AES voyage.