Direct adaptive current control a universal current control scheme for electrical machines

This paper presents a direct, adaptive and parameter-free current control scheme that is independent of the motor type and doesn\u27t need any machine parameters. A given setpoint can be reached accurately within one switching cycle

Neue Methode zur Bestimmung und Beschreibung der taktfrequenten Stromsteigungen in Drehstromsynchronmaschinen

Knowledge of the cycle-frequency changes in the machine currents is of great advantage for many methods of controlling modern, highly utilized electrical machines. But how can these changes in machine currents be reliably measured during operation? Is the very short time of the individual switching states sufficient? And how can the changes in the currents be described mathematically and interpreted physically? This work provides an answer to these questions

Multi-Parameter Analysis and Measurement of Resonances in Grid-Connected Converters with LCL Filters

LCL filters offer high attenuation of grid current ripple, but are challenging from a control perspective due to the resonant peak in their transfer function. The influence of selected individual parameters has already been the studied in several papers. This paper builds on this existing body of work and provides a more comprehensive analysis of all relevant variables influencing the resonance. In addition, dependencies between the parameters are explored. Stability and resonances are evaluated using frequency responses and an impedance based approach. Finally, the analysis results are confirmed with measurements

Easy current slope detection for low cost implementation of the direct adaptive current control for DC-DC-converters

"Direct Adaptive Current Control" (DACC) is a completely adaptive current control scheme with excellent control quality and high dynamics. It is based on the detection of the current slopes during each switching state of the utilized inverter and identifies the system within one period. No control path parameters are needed for setup. One method to measure the current slopes is fast oversampling of the current followed by a least squares estimator to filter the noise. This is well-proven but is difficult at high switching frequencies and implies the use of powerful hardware. In this paper a new algorithm for the detection of the current slopes in DC/DC-Converters is presented that does not need oversampling or a complex filter. Its simplicity allows for easy implementation in low-cost microcontrollers and yet be operated at high switching frequencies. The presented algorithm enables the implementation of the DACC as a low-cost, high dynamic and completely adaptive current controller for fast-switching DC/DC-Converters

Design guideline for PCB integrated, high bandwidth, current slope sensing based on a planar Rogowski coil

This paper shows the design process of a planar Rogowski coil integrated in the Printed-Circuit-Board (PCB) for direct current slope measurement. Focus lies on the analytic estimation of the coil parameters with respect to specific limitations and the analog signal processing for a simplified design process. All analytic derivations are verified by measurements

Cascaded H-Bridge based Parallel Hybrid Converter - A novel Topology for perfectly sinusoidal high power Voltage Sources

The demand for high voltage, high power, high precision and high dynamic 3AC-voltage sources is increasing constantly. One application that gets more and more important in recent years and demands such voltage sources is e.g. Power-Hardware-in-the-Loop (PHIL) Emulation. In this paper a new power converter topology called “Parallel Hybrid Converter” or PHC is presented and a corresponding control scheme is derived. This new converter has a terminal behavior similar to a MMC or MMPMC but compared to them the PHC features significantly reduced costs and a significantly improved power density