BIDIRECTIONAL AC-DC CONVERTERS USING ONE CYCLE CONTROL (OCC) FOR ELECTRIC VEHICLES

The electric vehicle (EV) market has seen a rapid growth in the recent past. With an increase in the number of electric vehicles on road, there is an increase in the number of high capacity battery banks interfacing the grid. The battery bank of an EV, besides being the fuel tank, is also a huge energy storage unit. Presently, it is used only when the vehicle is being driven and remains idle for rest of the time, rendering it underutilized. Whereas on the other hand, there is a need of large energy storage units in the grid to filter out the fluctuations of supply and demand during a day. EVs can help bridge this gap. The EV battery bank can be used to store the excess energy from the grid to vehicle (G2V) or supply stored energy from the vehicle to grid (V2G ), when required. To let power flow happen, in both directions, a bidirectional AC-DC converter is required. This thesis concentrates on the bidirectional AC-DC converters which have a control on power flow in all four quadrants for the application of EV battery interfacing with the grid. This thesis presents a bidirectional interleaved full bridge converter topology. This helps in increasing the power processing and current handling capability of the converter which makes it suitable for the purpose of EVs. Further, the benefit of using the interleaved topology is that it increases the power density of the converter. This ensures optimization of space usage with the same power handling capacity. The proposed interleaved converter consists of two full bridges. The corresponding gate pulses of each switch, in one cell, are phase shifted by 180 degrees from those of the other cell. The proposed converter control is based on the one-cycle controller. To meet the challenge of new requirements of reactive power handling capabilities for grid connected converters, posed by the utilities, the controller is modified to make it suitable to process the reactive power. A fictitious current derived from the grid voltage is introduced in the controller, which controls the converter performance. The current references are generated using the second order generalized integrators (SOGI) and phase locked loop (PLL). A digital implementation of the proposed control ii scheme is developed and implemented using DSP hardware. The simulated and experimental results, based on the converter topology and control technique discussed here, are presented to show the performance of the proposed theory.

Performance Information and Innovation in the Canadian Government (Working Paper 43)

The presentation made at the conference addressed the issue of linkages between performance information and innovation within the Canadian federal government1. This is a three‐part paper prepared as background to that presentation. • Part I provides an overview of three main sources of performance information - results-based systems, program evaluation, and centrally driven review exercises – and reviews the Canadian experience with them. • Part II identifies and discusses a number of innovation issues that are common to the literature reviewed for this paper. • Part III examines actual and potential linkages between innovation and performance information. This section suggests that innovation in the Canadian federal government tends to cluster into two groups: smaller initiatives driven by staff or middle management; and much larger projects involving major programs, whole departments or whole-of-government. Readily available data on smaller innovation projects is skimpy but suggests that performance information does not play a major role in stimulating these initiatives. In contrast, two of the examples of large-scale innovation show that performance information plays a critical role at all stages. The paper concludes by supporting the contention of others writing on this topic: that more research is needed on innovation, particularly on its link to performance information. In that context, other conclusions drawn in this paper are tentative but suggest that the quality of performance information is as important for innovation as it is for performance management. However, innovation is likely to require its own particular performance information that may not be generated on a routine basis for purposes of performance management, particularly in the early stages of innovation. And, while the availability of performance information can be an important success factor in innovation, it does not stand alone. The commonality of a number of other factors identified in the literature surveyed for this paper strongly suggests that equal if not greater priority needs to be given to attenuating factors that inhibit innovation and to nurturing incentives.