Performance evaluation and experimental validation of space vector PWM techniques with DC link voltage control in cascaded architecture of DC-DC stage followed by DC-AC stage for EV/HEV powertrain is carried out. 240°-Clamped PWM (240CPWM) and Advanced Bus Clamped PWM (ABCPWM) are the best performing PWM methods considering the combined performance of THD in line currents and efficiency. 240CPWM and ABCPWM are studied in detail both with constant and variable DC link voltage control and compared with benchmark PWM methods i.e., CSVPWM and DPWM1. Cascaded topology operation of DC-DC stage with DC-AC stage that allows the variable DC link voltage control in EV/HEV powertrain is studied in detail. Experimental results from a 10 kW hardware prototype are presented. Supremacy of one PWM method over the other is based on combined best performance in terms of THD and efficiency. 240CPWM outperforms all other PWM methods under consideration which is shown by a performance metric developed on the basis of combined performance of THD and efficiency.

There is currently a big thrust for integrating renewable resources to the electric grid. With increasing variable generation the need for energy storage devices has escalated. Traditional storage devices have bulky 60 Hz transformer to provide the electrical isolation from the grid. But, with the advent of advanced magnetic materials, power electronic topologies with high frequency link transformers are being researched. These systems have high power density and can be quickly dispatched for remote installations. This paper presents the design of the energy storage system consisting of the three phase rectifier and bi-directional dual active bride converter. It presents a methodology to optimize the switching frequency of the dual active bridge converter by minimizing the volume of the transformer and the total losses in the system. Frequency dependent and independent terms are aggregated and minimized over the range of switching frequency.

This paper presents an impedance based stability criterion of cascaded active converter systems with bi-directional power flow from the perspective of individual subsystems. Influence of bi-directional power flow on the impedance of the subsystems and the stability of the cascaded system are studied. Though bi-directional power flow does not change the stability criterion, it changes the impedance (mostly the phase) of the susbsystems. Unstable critical frequencies caused by impedance interaction are predicted by the proposed impedance criterion in bi-directional power flow situation. Simulation results of a cascaded system comprising of a dual active bridge (DAB) dc-dc stage and a H bridge dc-ac stage are presented as an example to verify the analysis of the influence of bi-directional power flow. The small signal impedance on the dc side of the single phase H bridge is calculated based on power balance analysis. Controller improvement approaches to eliminate impedance interaction between subsystems are discussed.

A robust power sharing controller for single phase inverter has been developed for the microgrid emergency condition where it is islanded from the main grid, and no communication available. In order to design a robust controller, the Glover McFarlane H infinity synthesis method is used. This design method guarantees the robustness of the droop controller and it allows to specify the settling time of the system during design process. The designed controller is applied to a single phase distribution network comprising of three solid state transformers (SSTs). The PLECS simulation results validate the robust performance of the controller with both load doubling and system topology changing contingencies. And the settling time of the system matches with the MATLAB analysis as designed.

A variety of distributed control strategies have been applied to microgrids, including master-slave, current mode control, and droop [1], [2], [3]. Droop control has received a great deal of attention and has been implemented with rudimentary modifications in order to improve performance [4], [5]. Prior work has typically assumed that the droop coefficients are constant and relied on elementary control design [6]. Two fundamental issues that have not been addressed using these approaches, are the ability to design an inverter to operate in a microgrid without analyzing the entire microgrid and improved transient performance using dynamic controllers of order greater than one. These issues will be addressed in this paper by designing a dynamic controller using Glover McFarlane loop shaping [7].

Electric power and energy engineering has as a basic tenet the relief of humankind of its burden, and the transmission and processing of information. In this paper, the salient advances of the first century of the electrification of the World is reviewed with special emphasis on the contemporary design and operation of electric power and energy systems. The advancements of power engineering are reviewed from a 2012 perspective, and issues of sustainability and the utilization of renewable resources are discussed.