Alexandre Battiston

Comparison Criteria for Electric Traction System Using Z-Source/Quasi Z-Source Inverter and Conventional Architectures

This paper deals with objective criteria to compare conventional electric traction systems composed of a dc-dc boost converter, a voltage source inverter, and a permanent magnet synchronous machine with alternative topologies such as Z-source inverter (ZSI) or quasi Z-source inverter (QZSI). Rather focusing only on efficiencies issues, this paper deals with other relevant criteria. The stored energy in the systems is for instance linked with their passive elements weight, size, or cost. The currents rms values and the stepup voltage ratio are also considered. A complete losses evaluation is given and validated by both simulation and experimental results. The results show that the QZSI exhibits real advantages in terms of passive elements size since the stored energy during one operating cycle is lower than that for the conventional topologies.

A Control Strategy for Electric Traction Systems Using a PM-Motor Fed by a Bidirectional

This paper deals with a control method that adapts the dc bus voltage of electric traction systems using permanent-magnet synchronous machine (PMSM) fed by bidirectional Z-source inverter (ZSI) or other improved topologies. This control allows reducing both the overestimation of the dc bus voltage and losses in the inverter. The sliding-mode control (SMC) method is used to control the Z-source converter, whereas flatness-based control is proposed to drive the actuator and generate the peak dc bus voltage reference. Flatness-based control is chosen because the actuator transients are well mastered. Extra shoot-through zero inverter states are inserted by means of implemented algorithm on a space-vector-modulation (SVM) scheme. Different short-circuit strategies are studied and compared according to constraint criteria. Both simulation and experimental results are presented and discussed to validate the proposed voltage adaptation strategy and the improvement on global efficiency.

Z

This work deals with the behavioral analysis of a DC/DC converter including a high performance source filter smoothing significantly the current supplied by the DC source. A low switching frequency is used for the converter. Elements of this filter should be of small sizes. To ensure good performances especially in transients, the control of this system is realized by a Fractional Order PID. The different coefficients involved in this controller are derived by optimizing a proper criteria using the Strength Pareto Evolutionary Algorithm SPEA. Simulation study and experimental tests are performed and their results are presented in the paper for validating the design of passive elements. They show satisfactory performances of the controlled system.

-Source Inverter

This paper proposes an improved control strategy for a quasi-Z-source inverter (QZSI)-fed permanent-magnet synchronous machine (PMSM)-based electric vehicle. The proposed strategy aims to improve efficiency of the powertrain with this particular dc/ac converter. For this purpose, it is proposed to adapt in real time the dc-bus voltage to the mechanical speed of the machine. The strategy is realized by implementing a control method based on the flatness properties of the system. These particular properties allow mastering all the state variable or input variable trajectories, which is interesting in the present case where the dc-bus voltage trajectory has to be well known. In order to increase the control dynamic, a one-loop flatness-based control is implemented. The structure thus allows increasing the controller bandwidth that helps in reducing the size of the dc-bus capacitors. Simulations and experiments on a 500-W powertrain are carried out to show that the proposed control strategy is effective and provides an efficiency improvement.

Behavioral analysis of a Boost converter with high performance source filter and a Fractional-Order PID controller

This paper deals with the one-loop flatness-based control of a Permanent Magnet Synchronous Machine fed by a coupled inductors Quasi Z-source Inverter. Among arguments in favor of this control strategy, it can be pointed out both the high mastering of the transient states and the high bandwidth of a one-loop control. Some improvements are proposed in this paper to saturate the state variables in order to prevent the system from having an uncontrollable behavior and thus to ensure its robustness when disturbances occur.

Efficiency Improvement of a Quasi-Z-Source Inverter-Fed Permanent-Magnet Synchronous Machine-Based Electric Vehicle

This paper deals with objective criteria to compare conventional electric traction systems composed of a DC-DC boost converter, a Voltage Source Inverter and of a Permanent Magnet Synchronous Machine with alternative topologies such as the Z-source or Quasi Z-source inverters. Analytical expressions are given and validated by both simulation and experimental results (efficiency).

Control of a PMSM fed by a Quasi Z-source inverter based on flatness properties and saturation schemes

Parallel voltage-source inverters with common dc bus present very interesting advantages from an industrial point of view. Indeed, by paralleling several units the power supply system includes capability to handle high power requirement, modularity and the possibility of maintenance through redundancy, within an uninterruptible supply operation. However, a special attention is required to avoid the negative effect of the circulating currents in such configuration caused essentially by the asynchronous switching operations of the Pulse Width Modulations (PWM) specified to each unit. To deal with this problem, in this contribution a one loop controller based on the flatness technique is proposed to an isolated power supply composed by N units. These units connect the same dc source and the ac load. The objective of the new sharing controller is to take some advantages of the flat proprieties of the system in order to ensure both reduction of the circulating currents and high power quality at the Point of Common Connection (PCC).

Comparison criteria for electric traction system architectures

With increasing levels of distributed generation systems connecting into the electrical grid, power electronics converters are widely applied to interface these systems to the grid and to provide various control functionalities. This paper presents a novel matrix converter topology with adapted control strategies for energy conversion in distributed energy systems. This topology with the associated control strategies offers the possibility to connect a high speed or variable speed generator to the grid as well as auto-start-up of the prime mover, gas turbine in this case. The proposed matrix converter topology performs two complementary functions. Start-up function during which a DC to AC conversion is performed from a battery to ensure the turbine start-up, and AC to AC conversion to connect the generator to the grid. Simulations and experiments on a 3 kW test bench are carried out to show that the proposed generating system is effective and provides a new solution for variable/high speed generating systems. Control law was implemented on DSP controller, experimental results are presented.