Effect of transmitter position on the torque generation of a magnetic resonance based motoring system

Strongly coupled magnetic resonance is most often used to transfer electrical power from a transmitter to a resonant receiver coil to supply devices over an air gap. In this work, the induced current in two receiver coils (stator and rotor) is used to generate torque on the rotor coil. The effect of the transmitter position relative to the stator and rotor receiver coils on the torque generation is studied in detail, both in simulation and experimentally. Results show a 36% to 37% gain in peak torque when properly varying the stator orientation for a given transmitter distance

Quasi-static Torque Profile Expressions for Magnetic Resonance Based Remote Actuation

Resonant wireless power transfer has been employed to transfer electrical power from a transmitter to a receiver coil over an air gap and to remotely charge consumer devices. In this paper, the receiver coil is replaced by a stator-rotor topology, enabling magnetic resonance based motoring over substantial air gaps. The principles of resonant wireless power transfer are used to induce currents in a strongly coupled magnetic resonance system. This results in its turn in torque, which is applied on the rotor body, allowing for remote actuation. We propose a voltage or current controlled magnetic resonance motoring topology, for which we derive expressions for the generated torque depending on the rotor angle. Furthermore, torque profile expressions are derived for motoring systems with multiple stator and/or rotor coils. Finally, an experimental setup is built to validate the obtained torque expressions. Using the validated expressions, we present a sensitivity analysis of the key system parameters with respect to the torque profile. The presented torque profile expressions enable further topology exploration and optimization of magnetic resonance based motoring systems

Computationally efficient modeling for assessing the energy efficiency of electric drivetrains using convex formulations

High-fidelity models capturing the dynamical behavior can be engaged for the analysis of complex mechatronic systems. Determining the optimal control parameters and design characteristics of such systems necessitates solving multiple interconnected models acting on their respective physical domains and time scales. In this paper, high-fidelity physics-based models are constructed for several electrical subsystems. Loss mechanisms in the various components are inferred because these are key when performing optimal design and control in terms of energy-efficient conversion from power source to actuation. The complexity of the analyzed models is then reduced by introducing convex approximations for the occurring dissipation during power transfers, allowing abstracting the complicated dynamic behavior into a tractable convex formulation, specifically suited for time-efficient numerical simulation. The effectiveness of the strategy is demonstrated on a case study originating from the field of all-electric vehicles, embodying a series interconnection of a battery stack, a buck-boost converter, a voltage source inverter, and an asynchronous electric motor. Results show that the dynamic simulation of the proposed system, composed of multiple time scales, can be reliably computed using the composed convex mappings, hereby reducing the computational time approximately by a factor 461, compromising only 1.8% accuracy regarding energy consumption assessment. The introduced convex formulation can therefore constitute the foundation for optimal control and design of complex mechatronic drives

Optimal torque actuations of an electric drivetrain using convex optimized power flows

This paper presents a methodology for the determination of the optimal torque set points actuated to a pair of induction machines which is part of a battery-converter-induction machine subsystem that on his turn is connected to a variable input load. The torque values of this large scale mechatronic system are determined by convex optimization of a general loss function incorporating switching losses, conduction losses, resistor losses, and mechanical friction of the considered drivetrain. Behavioral physics-based models are used to acquire the power flows and corresponding losses are calculated. The dynamic optimization formulation is casted to a convex minimization problem for the computationally efficient assessment of the torque set points. Results show that the proposed method is able to determine in a computationally efficient way the torque set points in this drivetrain for variable input loads

Remote electromechanical actuation using electrically resonant power transfer systems : design and optimal control

Magnetische resonante koppeling is een vorm van draadloze energieoverdracht die het mogelijk maakt om energie naar een ontvanger over te brengen zonder gebruik te maken van fysieke verbindingen zoals elektrische geleiders. Pas recent, in de laatste twee decennia, is de technologie rendabel geworden voor het gebruik in commerciële producten, zoals bijvoorbeeld elektrische tandenborstels en oplaadvlakken voor smartphones. De resonante werking van de zender- en ontvangerspoelen maakt efficiënte energieoverdracht mogelijk over luchtspleten die vele malen groter zijn dan de luchtspleten in klassieke elektrische machines. Dit proefschrift heeft als doel te onderzoeken hoe magnetische resonantie kan geïntegreerd worden in een elektrische machine om zo de luchtspleten te vergroten of magnetische materialen (deels) te vervangen door resonante spoelen. Dit onderzoek werd gevoerd in 3 stappen. In de eerste fase werden de elektrische interacties en krachtwerking tussen resonante spoelen beschreven en gevalideerd op een prototype opstelling. Typisch is het koppel hoog voor 1 bepaalde rotorpositie. In de tweede fase werd de resonante afstelling (detuning) van de resonatoren gevariëerd om zo het koppel te verhogen voor alle rotorposities. In de derde en laatste stap werd de fysieke implementatie van deze detuning onderzocht en gevalideerd op het prototype

Series and parallel capacitor compensation of the transmitter in a magnetic resonance based motoring system

Resonant wireless power transfer has been developed and employed for transferring power to electrical loads. In recent research, the induced currents were directly used to exert forces or torques on a movable resonator coil. A high variability is present in the torque profile of a resonance based motoring system. In wireless power transfer, multiple compensation methodologies exist to counteract the reflected impedance of the load and to optimize the power flow, efficiency and/or VA rating of the source. This paper investigates the effect of the capacitor tuning for the two most common compensation methods in wireless power transfer, namely series LC and parallel LCL compensation. As a result of the highly variable reflected impedance, the peak torque does not always coincide with the zero phase angle of the total load impedance or the transmitter current peak. The torque generation capability, namely the ratio of average torque to maximum current, of both methods is largely similar. The LCL method has a higher peak value, which does however not coincide with its efficiency peak, so a trade-off is required. The efficiency of the LCL topology is shown to be significantly larger than the series LC transmitter