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This paper proposes a DC–DC converter dedicated to high efficiency and high voltage conversion ratio, which is well suited for fuel cell applications. At high voltage conversion ratio the proposed converter, named here mirror boost converter, has a better ratio of active/freewheeling times which, compared with conventional structures, reduces the penalty on efficiency induced by the high conversion...
One of the main challenges associated to the More Electric Aircraft is to significantly increase power density of electrical power systems, such as electromechanical chains applied to actuation systems, without compromising on reliability. Nowadays, the best way of considerably increasing power density of power converters is by the use of disruptive technology such as Wide Bandgap (WBG) semiconductors.
This paper deals with a new concept of winding segmentation of permanent-magnet synchronous machines originally presented in a recently published patent. Called, in this paper, the coupled star winding, this new segmentation winding allows reducing total loss and current ripples when fed by an interleaved parallel inverters. This segmentation method can potentially integrate the functionality of magnetically...
Standard Voltage Source Inverters (VSI) operates with a DC voltage source greater than the peak voltage of the AC source and Current Source Inverters (CSI) with a DC voltage source lower than the peak voltage of the AC source. This paper shows how several topologies of reversible AC/DC buck-boost inverters which do not suffer from such constraints can be compared on the basis of semiconductor and...
Finding a global optimum of power converters requires models of all its parts (semiconductors, filters and cooling system), rules to describe the interactions between the different parts, an optimality criterion and optimization routines to converge towards the best design. In this paper we implement a model of forced-air cooling system to be used in such a design process. Heat exchange between fins...
Converter topology, power devices, passives elements and technology are the keys elements to achieve highly efficient and integrated converters. This article discusses each of these items with a point of load converter application in mind. The potential advantages of series connection are discussed: increase of both the specific power and the efficiency, reduction of semiconductors voltage rating...
In modern power electronics, the design of power converters relies on accurate modeling of losses of all components. Losses in the switches are usually the most important point to be considered in a converter design; however, switching losses are not always provided in datasheets. Typical methods for measuring switching losses, such as the double-pulse method, need the insertion of current and voltage...
The parallel association of classical commutation cells is a good solution for increasing the output current driven by the converters while the classical semiconductors technology are used. The control strategies used with this type of connection must be able to ensure good distribution of the output current among the different legs. This paper applies two control strategies based on the Model Predictive...
More compact power converters can be realized with the recently introduced gallium nitride (GaN) power devices. However, power board layout becomes more critical. In order to reduce switching losses, voltage overshoot and to achieve fast and safe drive, the stray inductances should be minimized. In this paper, a 5-phase DC-DC interleaved buck converter with an InterCell Transformer (ICT) integrated...
In this work we propose a control strategy based on Model Predictive Control (MPC) with variable commutation instants at constant frequency. Two stages are used by association of a reduced cost function and a state machine which selects the optimum state. The strategy is applied to flying capacitor converters connected in parallel, which requires the development of strategies capable to control the...
The parallel connection of classical commutation cells is a good solution for increasing the output current of classical power converters. Many control strategies have been proposed to fulfill the constraints of this connection, related mainly with the good distribution of the output current among the different legs. Model Predictive Control (MPC) is a recent control strategy that uses the system's...
Interleaving techniques applied to the parallel association of converters provide the reduction of the output current ripple and the increase of its frequency, leading to a reduction of the associated filters. The best way of paralleling commutation cells is by means of InterCell Transformers (ICT). The design of such special magnetic components strongly depends on the magnetic flux flowing through...
This paper presents a reconfigurable parallel interleaved inverter connected through InterCell Transformers (ICT) and driving two separate and identical AC loads. The proposed system can be connected to both 270V and 540V bus DC available in aeronautical applications, without any difference in the system operation and with no need of oversizing switches, filters and passive components. This feature...
The increase of electrical energy consumption in modern aircrafts stimulates manufactures to install a 540V DC bus in future aircrafts, together with the existing 270V and 28V DC buses. Energy transferred between the high voltage DC bus (HVDC, 270V) and the low voltage DC bus (LVDC, 28V) is made by bidirectional isolated DC-DC converters. A performing topology for these types of converters is the...
In a world of growing need for efficient energy conversion and distributed generation, Dual Active Bridge (DAB) converters represent a prominent converter topology given its soft switching properties and the low number of components, which allow the converter to be highly compact. Depending on the operating voltages and the transferred power, large circulating currents may occur. Parallel connection...
This paper presents a full EMC model of a 70 kW drive for Aircraft E-ECS (Electrical Environmental Conditioning System). The model includes the inverters, the ICTs (InterCell Transformers), the harness and the electric machine. The parameters of the model are extracted from either experimental identification or numerical simulation. After validation, the model is used in an optimization process to...
A new approach for easy & fast modeling and optimization of EMI filter used in aircraft application is proposed. A modular description in a user friendly environment allows describing the model and accounting for all technological parameters of the system: control strategy, inverter model (semiconductors, layout, etc.), filter, cables and AC machine. The model in the frequency domain is automatically...
The paper proposes an approach for easy and fast modelling and optimization of power electronics structures. It focuses on the EMC filter design. To achieve this task for electrical drives, a full EMC modelling of the application is defined by combining time simulation (or measurements), FFT and system modelling in the frequency domain. A modular description in a user friendly environment allows describing...
Multilevel structures are becoming more and more common in the industry because they can convert a DC voltage into an AC voltage for high-power and medium voltage condition. However there are limitations in some topologies where the DC Bus is divided by capacitors. With 3 or more DC bus capacitors, it is difficult to ensure the voltages balance across each capacitor. This paper proposes a 5-level...
This article presents a new Masterless Modular Current-Sharing (MMCS) technique. Current-sharing modules are identical and placed in a daisy chain configuration. Unlike classical current sharing which consists in comparing each phase current to a global computed average value, the presented masterless approach computes local current average values. Phase currents' balancing is achieved by comparing...
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