A recently proposed single-stage CSI with discharge path exhibits the ability to control the drive from zero speed without the insertion of an additional pre-stage converter to control the input DC current. In this paper the characteristics of this power converter are analyzed deriving expressions for the voltage gain of the CSI connected to PMSM, in both low speed and high speed regions. Furthermore, the limitations of the topology in terms of critical speed (i.e. the maximum allowed speed) and maximum torque in the whole range are underlined. To solve the issue, a proper design of the coupled inductor is necessary to guarantee the nominal torque in the whole speed range. Simulations are reported to evaluate the proposed approach.

Single-stage Current Source Inverters (CSIs), supplied by a DC voltage source, are an alternative to Voltage Source Inverters (VSIs) for applications that operate always above a base speed due to their intrinsic boost capability that allows to achieve higher speeds with limited DC voltage. The resonance problem given by the interaction between the output capacitor Cfand the motor inductor L0has been extensively studied for CSIs. Furthermore, it is found that the inductor Ldcon the DC side also affects the resonance. This leads to an additional LCL resonance on the output currents. This paper investigates the resonances of single-stage CSI using the average small-signal converter model. An analytical expression for the additional LCL resonance is computed and a control strategy is proposed to attenuate the peaks of the resonances. Simulations are reported to evaluate the correspondence between the average small-signal model and the full model developed in PLECS.

Wireless Power Transfer (WPT) allows the transmission of electricity from a power source to a receiving device without the need for physical cables or direct contact. For autonomous mobile robots, this allows to automate the charging process while avoiding exposed contacts and charging port wear. The present work details the design, numerical simulation and test of an inductively coupled WPT system for battery charging of autonomous mobile robots. In order to transfer power, the system exploits a Split Transformer topology based on commercially available E-shape ferrite cores.A 600W rated power prototype has been manufactured and experimentally characterized. The experimental results obtained are in agreement with the simulation ones.

Simultaneous power and data transfer to enable fast communication between the primary and the secondary sides of wireless power transfer (WPT) systems is rapidly growing, to improve system performance and enable interoperability. The present work details the design, numerical simulation and test of a simultaneous wireless power and data transfer (SWPDT) system for battery charging of autonomous mobile robots. The system implements independent multiple inductive channels for power and full duplex data transfer, that are combined on the same split transformer topology, based on commercially available E-shape ferrite cores. In particular, a main winding is used to transfer power, while auxiliary data windings on the outer wings are used to realize a bidirectional data communication, implemented by means of Manchester coding technique. Preliminary experimental results carried out on multiple inductive channels SWPDT prototype with rated power 600W and 1 Mbit/s data rate are presented, and are in agreement with the simulation ones.

For applications that operate always above a base speed (e.g. compressors, fans) the single-stage Current Source Inverters (CSIs), supplied by a DC voltage source, are an alternative to Voltage Source Inverters (VSIs) due to their intrinsic boost capability that allows to achieve higher speeds with limited DC voltage, as it regularly happens in more electric aircraft (MEA) and hybrid electric vehicles (HEVs) applications. The resonance problem in high speed region is taken into account for single-stage CSIs. Using additional voltage measures in the commonly used DC-link current control it is possible to damp the resonance of the CL filter adding a voltage loop only on the d-axis without reduce the bandwidth of the current loop. It is also shown that the DC-link current control is able to damp the resonance on the q-axis without the insertion of other control loops. Simulations are reported to evaluate the proposed method.

The Current Source Inverters (CSIs) are an alternative to Voltage Source Inverters (VSIs) for electric motor applications. Despite the advantageous characteristics of intrinsic voltage boost capability, absence of electrolytic capacitors and reduced machine voltage stress, the increased component count and the need of a pre-stage for the inductor current control have limited the adoption. For some applications which have to operate always above a base speed (e.g. pumps, actuators, fans), single-stage CSI converter with improved efficiencies have been proposed. Owing to the advantage of the direct measurement of the terminal voltage, a simple and robust sensorless control is proposed for a single-stage CSI converter. Simulations on a SiC-based CSI7 converter driving a Permanent Magnet Synchronous Machine (PMSM) confirm the validity of the proposed control, potentially paving the way to a larger adoption of the CSI7 topology for motor drive application.

Voltage Source Inverters (VSIs) are usually adopted for high-speed motor drive applications due to the topology simplicity and the wide availability of control strategies for this topology. An alternative is the Current Source Inverter (CSI) which allows to achieve high speed range with limited DC voltage due to its intrinsic boost capability, and this is of interest in aerospace applications or electrical vehicles (EV), but a pre-stage is necessary to control the DC input current. In this work an hybrid solution is proposed to extend the speed range of a single stage CSI (i.e. CSI without pre-stage) driving a Permanent Magnet Synchronous Machine (PMSM). In fact using a single stage CSI with DC current control, the machine cannot work properly in low speed region, so the control is composed by two different strategies: one is proposed in this work for low speed operations and the other one is already known for high speed.

Extended Kalman Filters (EKFs), Phase Locked Loops (PLLs), and Stator Flux Observers (SFOs) are widely used for sensorless control of Permanent Magnet Synchronous Motors (PMSMs) drives. Their use (in their most advanced version) is here extended, on the basis of model analogies and suitably-guaranteed closed loop stability properties, to the sensorless speed regulation control of Hybrid Stepper Motors (HSMs), in which position and speed sensors are not employed to reduce costs and increase robustness with respect to high temperature and high-vibration environments. Both realistic simulations and experimental results demonstrate the feasibility of the proposed methods in terms of closed-loop performance and robustness to parameters mismatch.

Wireless power transfer systems are characterized by a loosely coupled magnetic circuit and a power electronics interface. For the optimization of the system power factor, a compensation circuit composed of capacitors is adopted to form a resonant tank with the power coil. The behavior of the overall circuit in terms of power transfer and current/voltage waveform depends on several parameters, which can make the analysis and optimization of the system complex. This paper proposes an analytical derivation of an equivalent RLC system that greatly simplify the design in terms of Zero Voltage Switching (ZVS) regions. In addition to this, the RLC equivalent circuit allows an easy analytic calculation of the output power depending on all WPT system parameters. The analytical model will be validated by simulation results.

Electrical motors are required to perform reliably for a certain number of hours/cycles. Assuming the insulation breakdown as the predominant source of failure, then the lifetime of an electrical machine can generally be said to correspond to that of its weakest insulation sub-system. Among all the insulation stressing factors, thermal aging is a primary source of progressive deterioration, and, eventually, failure. In order to guarantee a satisfactory lifetime, motors are designed to have thermal operational points which are always lower than their insulation thermal class. However, this design choice does not allow to maximize the exploitation of the insulation lifetime capability. Technical standards report methods for the thermal qualification of electrical machines based on accelerated thermal aging tests. Such assessment, despite enabling the insulation lifetime estimation, might require several thousand hours of testing. This paper, therefore, proposes and validates a new methodology which considerably shortens the thermal qualification of electric motors.

Current source inverter (CSI) is a family of power converters which has been recently investigated for photovoltaic power conversion in grid-tied operation, due to the inherent boost capability and ease of control. This paper assess Photovoltaic three-phase Current Source Inverters by two different CSI topologies and space vector modulation commutation strategies. Different CSI solutions are therefore analyzed by means of numerical simulations and the results are compared in terms of ground leakage current and THD of the injected grid currents. Extensive simulation results show that the CSI7 topology can improve the common mode performance while at the same time increasing the efficiency of the conventional CSI, at the price of a negligible added complexity.

This paper presents a grid-tied single phase photovoltaic microinverter based on Current Source Inverter (CSI) topology. The main topic of this work is related to the identification of a topology and a PWM strategy able to minimize the obvious issues of the basic CSI solution: efficiency and ground leakage current. The strong reduction of this last issue allows the use of the proposed solution in conjunction with Photovoltaic module in building integrated installations. Simulation results and a low voltage experimental validation present the effectiveness of the proposed solution in mitigating ground leakage currents.