Ralph Kennel - Profile on Academia.edu (original) (raw)

Papers by Ralph Kennel

Power Optimization Control with Tracking Differentiator for Interior Permanent-Magnet Synchronous Motor

Lecture notes in electrical engineering, 2023

Extended Prediction Horizon Multi-objective FSMPC without Weighting Factors

2023 IEEE International Conference on Predictive Control of Electrical Drives and Power Electronics (PRECEDE)

Cooperative Decision-making Approach for Multi-objective Finite Control Set Model Predictive Control without Weighting Parameters

IEEE Transactions on Industrial Electronics

A New Five-Level Grid-Connected PV Inverter Topology Controlled By Model Predictive

IECON 2022 – 48th Annual Conference of the IEEE Industrial Electronics Society

A New Multisource Inverter Topology for Electrical Vehicle Applications Controlled by Model Predictive

IECON 2022 – 48th Annual Conference of the IEEE Industrial Electronics Society

Bandwidth Improvements of Linear Direct Drives with a 100 kHz PWM-Frequency

2019 12th International Symposium on Linear Drives for Industry Applications (LDIA)

A calculation method for a robust servo controller design depending on the sampling time and the ... more A calculation method for a robust servo controller design depending on the sampling time and the processing dead time was developed for mechanically stiff drives. With a test stand for high dynamic and high positioning accuracy, the theoretical calculations for the high bandwidth improvements are verified. The test stand includes a voice coil motor and a power electronic with Gallium Nitride (GaN) power semiconductors for switching frequencies of more than 100kHz.

Computationally Efficient Predictive Current Control With Finite Set Extension Using Derivative Projection for IM Drives

IEEE Journal of Emerging and Selected Topics in Power Electronics

Anisotropy-based Sensorless Control for Electrical Drives – Part I: Basic Principle

2021 22nd IEEE International Conference on Industrial Technology (ICIT)

This paper covers the basic principle related to the anisotropy-based1 sensorless control for ele... more This paper covers the basic principle related to the anisotropy-based1 sensorless control for electrical drives. Several anisotropy-based methods were developed to solve the failure problem of fundamental model based methods in the lower speed, and at zero speed of electric machine. The objective of this paper is to help the reader develop a systematic understanding of this technique that has been developed over the past three decades.

Three-Phase Model-Based Predictive Control Methods With Reduced Calculation Burden for Modular Multilevel Converters

IEEE Journal of Emerging and Selected Topics in Power Electronics

Tube-based robust current control of induction motors

2019 14th IEEE Conference on Industrial Electronics and Applications (ICIEA), 2019

This paper develops a current controller for the induction motor (IM) to improve the control robu... more This paper develops a current controller for the induction motor (IM) to improve the control robustness against parameter variations, which are mainly caused by the condition changings in IM during operation. We use tube-based robust model predictive control (TMPC) as the current controller for IM to tackle the parameter mismatch problem. In TMPC the nominal constraints are tightened by the robust positively invariant set. The control laws of the optimization problem described by the TMPC are computed off-line by solving the multi-parameter quadratic programming, which significantly reduces the online execution time of the controller. Simulation results indicate that TMPC is more robust than PI and explicit model predictive control (EMPC). TMPC has lower searching burden than EMPC, which further improves the dynamics of the controller. Real-time feasibility of TMPC up to 8kHz sampling rate is demonstrated by experiments.

A predictive direct power control strategy for three-level npc rectifier

2017 5th International Conference on Electrical Engineering - Boumerdes (ICEE-B), 2017

In this paper, a predictive direct power control (P-DPC) strategy for a three level NPC rectifier... more In this paper, a predictive direct power control (P-DPC) strategy for a three level NPC rectifier under ideal grid voltage is proposed, discussed and applied. With the proposed P-DPC strategy, the control targets are the active power, the reactive power and the neutral potential voltage; neither hysteresis comparators nor switching table are needed; sinusoidal input current with low total harmonic distortion (THD), smooth regulation of both powers (active and reactive power), and neutral point voltage are achieved. Finally, by using Matlab/Simulink, the performance and effectiveness of the proposed P-DPC strategy is verified via simulation results.

High-Performance Position Sensorless control of Reluctance Synchronous Motor using High-Frequency Injection

2019 IEEE 13th International Conference on Power Electronics and Drive Systems (PEDS), 2019

This paper presents an enhanced method for a self-sensing (Sensorless) Field Oriented Control (FO... more This paper presents an enhanced method for a self-sensing (Sensorless) Field Oriented Control (FOC) of Reluctance Synchronous Motor (SRM) based on high-frequency signal injection. The rotor saliency characteristic with the difference between the ddd-axis and qqq-axis inductance of the motor is used for position estimation through adding a small high-frequency current signal injected in an arbitrary rotating frame. Modulation technique is applied to the sensed voltages and currents to extract a signal that is proportional to the difference between the actual position and an estimated position. This error signal is used as input to a Phase-Locked Loop (PLL) to get the position and the speed of the machine. Particle Swarm Optimization technique (PSO) is used to tune the parameters of speed, current and PLL controllers. The major objective of this drive is to give a robust and dynamic estimation of the rotor angle and speed independent of the operating condition. The proposed methodology is validated by simulation results to clarify the ability of the proposed technique in different speed area.

Enhanced Sensorless Model Predictive Control of Induction Motor Based on Extended Kalman Filter

2019 IEEE Conference on Power Electronics and Renewable Energy (CPERE), 2019

This paper presents an enhanced method for a self-sensing (Sensorless) Model Predictive Control (... more This paper presents an enhanced method for a self-sensing (Sensorless) Model Predictive Control (MPC) of Induction Motor (IM) supplied form two-level using state-space model. For the self-sensing process, the controller needs a proper position and speed observer. In this paper, the position and speed of the rotor are estimated based on Extended Kalman Filter (EKF). The proposed EKF is executed to achieve a small error in the estimation parameters of IM in transient and steady-state operation. Model predictive control uses all the mechanical and electrical variables to calculate a cost function for each switching state of the inverter. The voltage that achieves the lowest errors (lowest cost function) is selected to be applied in the next sampling interval. High level of flexibility is obtained using the proposed control technique over a wide speed range with a fast dynamic response. The proposed methodology is validated by simulation results to clarify the ability of the proposed control algorithm in different speed area.

An Improved FCS-MPC algorithm with Imposed Optimized Weighting Factor

Design of a Low Multi-Loop Inductance Three Level Neutral Point Clamped Inverter with GaN HEMTs

2020 IEEE Energy Conversion Congress and Exposition (ECCE), 2020

This work shows a numerical and experimental analysis of a Neutral-Point-Clamp (NPC) three level ... more This work shows a numerical and experimental analysis of a Neutral-Point-Clamp (NPC) three level inverter featuring an ultra low inductance printed circuit board (PCB) design in consideration of the mutual inductive and capacitive couplings. The commutation loops in this design are found to be strongly dependent on the vertical thickness of the used prepregs and the core. For vertical thicknesses ≤ 100 µm capacitive coupling must be taken into account in the switching cell design. Experimental measurements of a test set-up with a total PCB thickness of 400 µm results in commutation loop inductances from 1.4 nH up to 3.1 nH. In this set-up, switching tests without external gate resistor showed only a maximum voltage overshoot of 7% at 800 V. Based on a numerical analysis of the NPC cell we propose a further switching performance improvement with significant smaller parasitic inductance due to the application of novel printed circuit technologies such as the integration of bare dies into the printed circuit board or polyimide as an interlayer dielectric material.

Space Vector Modulation and Neutral Point Voltage Balancing in a Four Leg Neutral Point Clamped (4LNPC) Converter

Improved DC-link Voltage Utilization for Dual Three-phase Drives with Full Anti-windup and Harmonic Compensation

2021 22nd IEEE International Conference on Industrial Technology (ICIT), 2021

The paper presents a new control strategy for the asymmetrical dual three-phase IPMSM, which can ... more The paper presents a new control strategy for the asymmetrical dual three-phase IPMSM, which can optimize the voltage dispatch for the torque production and harmonic compensation to obtain a wide constant torque-speed range with an improved dc-link voltage utilization, especially in field-weakening mode. Depending on the operating point, a full or partial harmonic compensation is achievable. Eventually, the current controller produces the desired torque while minimizing the stator copper losses.

Encoderless Parallel Predictive Torque Control for Induction Machine Using a Robust Model Reference Adaptive System

IEEE Transactions on Energy Conversion, 2021

This paper proposes a robust model reference adaptive system (MRAS) estimator incorporating onlin... more This paper proposes a robust model reference adaptive system (MRAS) estimator incorporating online parameter identification algorithm for parallel predictive torque control (PPTC) scheme. In contrast to conventional predictive torque control (PTC), the proposed PPTC is designed to facilitate the determination of weighting factor that modifies the relative importance of the control objectives, by simultaneously evaluating the torque and flux tracking error terms. The weighting factor is fine-tuned via an adaptive selecting mechanism, to obtain the attractive feature of reduced torque and current tracking errors. Besides, an encoderless MRAS-based estimator is employed for rotor speed and stator flux estimation to reduce the hardware complexity. However, this proposed encoderless PPTC algorithm still suffers from weak robustness against inevitable disturbances caused by parameter variations, which is an important issue to be further investigated. In this paper, an encoderless MRAS estimator combined with online parameter identification algorithm is proposed as an effective solution to accurately estimate the rotor speed and predicted stator flux-linkage, that improves robustness against mismatched parameters for the proposed encoderless PPTC scheme. The feasibility of the proposed algorithm is verified through the obtained experimental measurements, that achieves precise speed tracking capability as well as reduced torque and current tracking errors.

Multiple-Vector Direct Model Predictive Control for Grid-Connected Power Converters with Reduced Calculation Burden

2019 IEEE International Symposium on Predictive Control of Electrical Drives and Power Electronics (PRECEDE), 2019

This paper proposes a multiple-vector direct model predictive control (MV-DMPC) scheme with reduc... more This paper proposes a multiple-vector direct model predictive control (MV-DMPC) scheme with reduced calculation burden for grid-connected power converters. The proposed control scheme is based on the discrete space vector modulation (DSVM) technique, where the real voltage vectors (VVs) of the converter are employed together with new virtual VVs to improve the steady-state performance of the proposed controller. Furthermore, in order to reduce the calculation burden of the proposed strategy, a deadbeat function is presented to directly compute the reference voltage vector from the demanded reference current/power. Then, the optimal real or virtual voltage vector is selected based on a certain cost function to apply in the next sampling instant. The performance of the proposed method is validated via simulation results and compared with that of the conventional DMPC and the well-known voltage oriented control (VOC) with proportional-integral (PI) controllers.

Extended Kalman Filter based Encoderless Predictive Current Control for Induction Machine Drives

2021 IEEE 12th Energy Conversion Congress & Exposition - Asia (ECCE-Asia), 2021

Compared with the conventional strategies for electrical drives such as Field Oriented Control (F... more Compared with the conventional strategies for electrical drives such as Field Oriented Control (FOC), Predictive Current Control (PCC) shows the superiority of fast dynamic response and low switching frequency. Instead of an encoder, a speed-sensorless algorithm is applied to provide the rotor position for PCC, which reduces the hardware cost and complexity. However, the estimation accuracy is significantly penalized by the parameter deviation, which leads to unsatisfactory control performance like high torque and current ripples. To cope with this problem, an Extended Kalman Filter (EKF) is presented to estimate stator flux and rotor speed in this paper, which improves robustness to parameter variations and achieves high control performance. The steady-state, dynamic transient performance and robustness evaluation of the proposed scheme are experimentally validated on the 2.2kW induction machine (IM) platform. It is indicated that the proposed method shows excellent speed tracking ability and strong robustness to parameter deviations.