Daniel Sadarnac

Multiphysic Modeling of a High-Speed Interior Permanent-Magnet Synchronous Machine for a Multiobjective Optimal Design

High-speed electric drive design is concerned with paying particular attention to thermal and mechanical design of the machine. Therefore, this paper proposes a multiphysic modeling of an interior permanent-magnet synchronous machine (IPMSM) dedicated to high speed, including magnetic, electric, thermal, and mechanical aspects. The proposed analytical models are verified using finite-element (FE) computations. These models are then subjected to a multiobjective optimization-based on genetic algorithm-to design an IPMSM for a high-speed compressor application that develops 30 kW at 20 000 r/min. The design is formulated as a constrained optimization problem consisting of maximizing the machine efficiency while minimizing its weight. The result of this process is a Pareto front between efficiency and weight of the machine allowing the designer to make a posteriori choice. A particular optimal machine is chosen and its performances are validated with FE analysis. This study carries out an optimal multiphysic and multiobjective design approach that allows rationalization of the design process in a realistic computation time thanks to the analytical models involved.

A review of on-board integrated chargers for electric vehicles

Electric vehicles (EVs) use grid power to charge their batteries. Because the battery is charged only when the car is parked -except for regeneration at braking-, using the on-board traction system components to form an integrated charging device is made possible. This paper presents a review of on-board integrated EV chargers and design criteria. It is aimed at presenting a state of the art on the integrated chargers to researchers, designers, and engineers. A classified list of around 70 research articles is also appended for a quick reference.

Input filter influence on the control stability of DC/DC converters

Today, almost all converters have an input filter to control EMI/EMC. For most, the sizing of the filter is depending on the required attenuation from the applicable standard. For some standard that leads to very large attenuation, the input filter has more attenuation than the output filter. This study shows the interaction of the input filter and the converter regulation on both aspects of the equations and the physical understanding. We also propose a method to stabilize the whole system (filter, converter and control) without over sizing. Three basic DC/DC converter structures (the buck, the boost and the buck-boost converters) with and without transformer are studied in both modes: discontinuous current mode and continuous current mode.

The double discontinuous mode operation of a converter: a method for soft switching

This paper describes a way of ensuring soft switching in a converter without using additional components. This method is called double discontinuous mode (DDM). In particular, it permits any free wheeling diode to switch off at zero current, and for transistors to switch on at zero current and to switch off at zero voltage. The method illustrated here refers to a buck, but this concept may be applied to any type of converter, with or without transformer. Various mathematical models of this method are developed, and its characteristics and fields of application highlighted in this paper.

Analytical and FEM magnetic optimization of a limited motion actuator for automotive application

The present work proposes a development of a limited motion actuator dedicated to the air flow regulation of an internal combustion engine. A mixed analytical-FEM optimal design methodology is presented. An analytical study of a bipolar permanent magnet actuator has been done with a first geometrical optimization under constraint by a Genetic Algorithm. Then, the analytical study is coupled with Matlab® and FEMM freeware in order to integrate a finite element method and a second optimization with a Direct Search Algorithm. The actuator performance is specified for a small volume with a maximized torque on an angular range from 0 to 100°.

Hysteresis describing method for control of an active power filter

A hysteresis describing method is proposed to control and design an active power filter. The describing function used to develop this method consists of the linearisation of the non-linear current control loop. The linearisation is done by deriving the hysteresis complex describing function to find the stability condition of the closed-loop current. Under this condition, the frequency and amplitude values of the error signal correspond to the maximum switching frequency and the current ripple, respectively. The proposed method permits calculation of these parameters in a simple algebraic equation as a function of the hysteresis band, dc bus voltage and inductive filter value. Moreover, the compromise between the dc bus voltage and inductor value can be evaluated easily as a function of both switching frequency and ripple requirements. Two design examples are worked out. Experimental results validate the theory.

High frequency modeling of peak current mode control of DC-DC converters

The controlof power converters can be difficult if high dynamic performance is required, especially against the variations in supply voltage and load. This difficulty can further increase in the presence of input filters, which are intentionally underdamped to decrease the converter losses. In such cases, the peak current mode control facilities the design of control law. The usual approach for the modeling of this type of control assumes constant current ripples in smoothing inductance. However, this assumption is somewhat restrictive and limits the validity of the model at high frequency. This paper presents a modeling approach which avoids this assumption, consequently leading to a better representation of the converter at high frequencies. In order to improve its performance with respect to load and line disturbances, this kind of control implicitly integrates a feedforward compensation. The application of the developed analysis is carried out on a back converter; however, it is equally applicable to any other type of converter

Efficiency investigation of dc–dc converter with passively damped input filter circuit

Passive damping of input filters in dc–dc converter applications has suffered enormous criticism presumably due to high conduction losses in the damping resistors. However, an accurate quantitative assessment of their adverse impact on efficiency is lacking. Similarly, not enough attention has been paid to the severity and extent to which they can effectively deteriorate a converter-efficiency under varying operating conditions. In order to quantify these losses we have performed a generalised power-loss analysis that helps in predicting this harmful effect of damping resistors on overall filter-converter system efficiency. A practical damping approach using a shunt R–C network, which is most commonly suggested in dc–dc converter applications, is investigated theoretically as well as experimentally. Results show that converter efficiency is susceptible to severe degradation, especially at high loads as well as at smaller damping resistor values. Furthermore, it is shown that these losses are considerably higher in buck-type converters than in boost-type converters. Authors emphasise that considering this negative impact on power economy is of crucial importance while optimising such a damping network.

Steady state performance computation of a synchronous machine using harmonic resolution

This paper develops a method for analyzing the constant speed steady state of a three phase excited synchronous machine fed with any periodic voltages. The dq Harmonic Balance method is extended to account for back emf - linkage flux - and its time harmonics in current and torque waveform determinations. The method is applied to the case of surface mounted permanent magnet machines and to the case of interior permanent magnet machines with circumferentially magnetized magnets. Comparisons of current and torque waveforms obtained by time resolutions, finite element computations, and experimental measurements are performed and are favorable when the magnetic material linear hypothesis is verified. Moreover, the method is low computation time consuming and so it is suitable for rapid analysis of machines and for iterative optimal design procedures.