Design, analysis and development of new buck-boost and reduced EMI power conversion technology

The newly proposed Z-Source inverter has been proven in the literature to exhibit both steady-state voltage buck and boost capabilities using a unique LC impedance network coupled between the power source and converter circuit. This paper now presents transient modeling and analysis of a voltage-type /.-source inverter. These aspects are found to be challenging and they need to be carefully investigated before attempting to design advanced control algorithms for controlling the /.-source inverter. Through detailed analysis, the paper identifies several phenomena on the dc and ac-sides of the inverter, which would result in the inverter having an inferior non-minimum-phase transient response. The dc-side phenomenon is associated with the Zrsource impedance network, which is shown through small-signal and signal-flow-graph analyses to be having a right-half-plane zero in its control-to-output transfer function. Also, the ac-side phenomenon is shown through space vector analysis to depend on the time intervals of inverter states used for reconstructing the desired inverter output voltage. Based on the ac vectorial analysis, a method for improving the inverter transient response is also presented. Lastly, simulation results obtained using a switching-functional model and experimental results obtained using a laboratory prototype are presented for validating the described theoretical concepts

Maximum power point tracking technique implementation of Z-source inverter through finite step model predictive control strategy

This paper presents techniques of maximum power point tracking (MPPT) implemented with finite step model predictive control (FSMPC) for the application of Z-source inverter. Incremental conductance MPPT algorithm and FSMPC model is developed to control the output current of the grid-tied Z-source inverter in order to extract maximum solar power from the panel and then directly injecting the power into grid. The output current, passive component voltage and current are well regulated with proposed MPPT based FSMPC control strategy. Simulation of this proposed control algorithm is conducted in Matlab platform with PLECS toolbox. Both steady-state and transient results show that the high efficient and robust response of the proposed control technique

Single stage buck-boost DC-AC neutral point clamped inverter

This paper proposes a new single stage buck-boost DC-AC neutral point clamped inverter topology which integrates the cascaded configurations of recently introduced inductor-capacitor-capacitor-transformer impedance source network (by Adamowicz) and classic NPC configuration. As a consequence, it has enhanced buck-boost functionality and low output voltage distortions compared to the traditional Z-source inverter; it has continuous input current which reduces the source stress and inverter noise; it also contains two built-in capacitors which can block the DC current in the transformer windings thus preventing the core from saturation; lowers the voltage stresses and power losses of inverter switches and reduces the sizes of filtering devices and as well as obtains better output performance compared to the original two-level Z-source inverters. A phase disposition pulse width modulation technique with minimum switching counts is implemented for the proposed topology. Simulation results as well as experimental results are presented to verify the behaviors of proposed configuration

Reliability-based long term hydro/thermal reserve allocation of power systems with high wind power penetration

In a power system with high wind power penetration, reserve allocation is a major problem of system planning and operation due to the uncertainty and fast fluctuation of wind speeds. In order to achieve long term sustainable solution for electricity supply, the impacts of the installation of wind farms on system reliability have to be carefully studied. This paper describes the impact of installation of wind farms on the system reserve and reliability from a long term planning point of view. A multi-state wind farm model and a multi-state load model are combined using universal generating function (UGF) to simulate the fluctuation of wind speed, reliability of wind turbine generators and uncertainty of load. A reliability-based hydro/thermal reserve allocation method is proposed to determine the conventional reserve required for power systems with high wind power penetration. The IEEE-RBTS has been modified to illustrate the applications of the proposed method.Accepted versio