Tobias Glück

Digital Slew Rate and S-Shape Control for Smart Power Switches to Reduce EMI Generation

Smart power switches are power switches with integrated control and protection functions for the switching of middle- and high-current loads. In particular in automotive applications, smart power switches have to be operated without additional stabilization networks, EMI filters, and heat sinks to keep the weight, required space and costs of the circuit boards as low as possible. Therefore, the generated electromagnetic emissions must be reduced by another measure without significantly increasing the switching losses. This can be achieved by the active control of the first and/or second derivative of the output voltage. This paper presents a digital slew rate control and its extension to an S-shape control strategy, which in addition to the slew rate, also controls the second derivative of the output voltage. Both strategies are based on feedforward gate current profiles, which are iteratively adapted by an iterative learning control strategy to compensate for load variations and temperature dependences. A rapid prototyping test bench is presented, and the performance and robustness of the control strategies are demonstrated by a series of measurement results. An EMC compliance test according to the CSIPR 25 standard shows that the generation of conducted electromagnetic emissions can be reduced in a power efficient way by the proposed approach.

Swing-up control of a triple pendulum on a cart with experimental validation

The swing-up control of a triple pendulum on a cart is presented, where the controller is based on a two-degrees-of-freedom scheme consisting of a nonlinear feedforward controller and an optimal feedback controller. The point-to-point transition task is treated as a nonlinear two-point boundary value problem with free parameters resulting from the suitably projected input-output dynamics. The main focus of the paper is on the experimental realization of the triple pendulum swing-up maneuver.

Slew rate control strategies for smart power ICs based on iterative learning control

Smart Power ICs are Power Switches with integrated control and protection functions for the switching of middle and high current loads in industrial and automotive applications. Due to customer specifications and electromagnetic compatibility requirements it is often desired to limit the current and voltage slew rate at the output terminal of the Smart Power IC by minimizing the switching losses at the same time. In order to reduce the development effort and costs, a reusable control strategy is strived for. Therefore, a power optimal digital slew rate control strategy is developed which allows for a systematic limitation of the current and/or voltage slew rates. The strategy is based on the optimization of a gate current profile using Iterative Learning Control. A rapid prototyping test bench is developed for the verification of the control strategy. The performance and robustness is demonstrated by means of measurement results.

Combined path following and compliance control with application to a biaxial gantry robot

This work presents an approach to simultaneously, but independently control the compliance of a robotic system transversal and tangential to a given curve. Therefore, a path following control concept known as transverse feedback linearization and a compliance control concept known as admittance control are combined. The subordinate path following controller transforms the nonlinear dynamics into a linear system with decoupled transversal and tangential dynamics via a coordinate and feedback transformation. The outer control loop utilizes admittance control to obtain the desired target compliance in the respective transformed coordinates. The proposed approach is applied to a biaxial gantry robot. Experimental results underline the feasibility of the proposed concept.

Mathematical modelling of a hydraulic accumulator for hydraulic hybrid drives

ABSTRACT Hydraulic accumulators are used as energy storages in a wide area of applications. In particular, in automotive hybrid drive-trains, this type of energy storage is an interesting alternative to today’s common strategies like chemical batteries or flywheels. This article deals with the mathematical modelling of a hydraulic accumulator for passenger vehicles, which comprises a carbon fibre reinforced plastic (CFRP) body and aluminium piston. The thermodynamical behaviour of the oil and gas as well as the interaction with the CFRP body is investigated in detail. Starting from a complex model, two models of reduced complexity are derived. The validation of these models with measurement data from a test drive with a prototype series hydraulic hybrid drive-train proves their high accuracy.

Trajectory optimization for soft landing of fast-switching electromagnetic valves

Abstract The design of a feedforward controller that facilitates soft landing and time optimality of a fast-switching electromagnetic valve is presented. In particular, a mathematical model of the considered pneumatic switching valve is developed and parametrized by means of nonlinear parameter identification. Based on this model, the input constrained point-to-point quasi-time-optimal control problem is formulated and the resulting two-point boundary value problem is numerically solved. Due to the input constraints, the quasi-time-optimal control trajectories show bang-bang behavior. The performance of the numerically determined trajectories are demonstrated by means of measurement results on an experimental test bench.

Power optimal gate current profiles for the slew rate control of Smart Power ICs

Abstract Smart Power ICs are Power Switches with integrated control and protection functions. In order to meet the electromagnetic compatibility requirements, the output terminal slew rate has to be limited during the switching operation. In this context, special feedforward gate current profiles are widely used to control the switching slew rate. These profiles are typically determined on the basis of a linearized mathematical model of the Smart Power IC. However, due to the nonlinear characteristics of the IC, these profiles may lead to a reduced switching speed and thus to higher switching losses. In this work, an optimal control problem is considered which systematically accounts for the nonlinearities of the Power Switch, the switching losses and the limitation of the slew rate. In particular, a tailored mathematical model of the Smart Power IC is developed and parametrized. Based on this, the optimal control problem is formulated, numerically solved and the results are presented.

Dreistufiger Kolbenkompressor mit vorgeschaltetem Drehkolbenkompressor: Teil 1, Modellierung

Zusammenfassung Dieser Beitrag beschäftigt sich mit der mathematischen Modellierung eines dreistufigen Kolbenkompressors mit vorgeschaltetem Drehkolbenkompressor, welcher zur Produktion von PET-Flaschen eingesetzt wird. Ausgehend von den Grundgesetzen der Thermodynamik werden die Einzelkomponenten des Kompressors mathematisch modelliert und der zugrunde liegende Kreisprozess beschrieben. Anhand von Simulationsstudien wird das Verhalten des Kompressors im belasteten Fall untersucht. Das entwickelte Modell dient als Grundlage für den Reglerentwurf im zweiten Teil dieses Beitrags. Abstract This paper presents the mathematical modeling of a three-stage compressor with upstream roots blower. The individual components of the compressor are modeled based on the fundamental laws of thermodynamics in order to describe the underlying cyclic process. Simulation studies are carried out in order to analyse the behavior of the compressor. The developed model provides the basis for the subsequent controller design in the second part of this paper.

Convex Constrained Iterative Learning Control Using Projection: Application to a Smart Power Switch

This brief presents the application of convex constrained iterative learning control (ILC) using projection to the systematic slew rate control of smart power switches. Criteria for the monotonic and global convergence of the input and output iteration are presented for general first-order ILC laws with projection. Convergence of the ILC-based slew rate control for a smart power switch is analyzed and experimental results are shown.

Resistance estimation algorithm for self-sensing magnetic levitation systems

Abstract An algorithm for the estimation of the electric resistance for self-sensing magnetic levitation systems is presented. The development of this novel estimation algorithm is based on the position estimator proposed in Gluck et al. (2010). Based on the mathematical model of the considered magnetic levitation system, the main ideas of the position estimation algorithm are summarized. A detailed analysis shows that the estimation error of the electric resistance can be deduced from the results of the position estimation algorithm. This observation leads to the design of a new resistance estimation algorithm. The performance of the proposed algorithm is demonstrated by means of measurement results on a test bench.