@inproceedings{WittmannHaglKennel2016, author = {Wittmann, Josef and Hagl, Rainer and Kennel, Ralph}, title = {Influence of Position Measuring Errors on Speed Ripple in Servo Drives}, series = {2016 International Symposium on Power Electronics, Electrical Drives, Automation and Motion (SPEEDAM, Capri, Italy}, booktitle = {2016 International Symposium on Power Electronics, Electrical Drives, Automation and Motion (SPEEDAM, Capri, Italy}, year = {2016}, abstract = {Position measuring devices with sinusoidal measuring signals are widely used in position-controlled servo drives in industrial automation, e.g., for machine tools or semiconductor production machines. Usually, the feedback signal for the speed or velocity controller is calculated from the measured position. Therefore, position measuring errors affect these control loops. This study presents an analytic error model that considers non-ideal sinusoidal measuring signals with basic deviations (amplitude differences, offset errors, and phase shift) as well as signal harmonics. The model was used to systematically investigate the influence of signal quality and the number of signal periods from position measuring devices on speed ripple, across a wide range of speeds. A test stand with a high-resolution reference angle measuring device was used to confirm the results.}, language = {en} } @inproceedings{WittmannHaglKennel2017, author = {Wittmann, Josef and Hagl, Rainer and Kennel, Ralph}, title = {Hybrid Current and Acceleration Control of Servo Drives}, series = {PCIM Europe 2017 - International Exhibition and Conference for Power Electronics, Intelligent Motion, Renewable Energy and Energy Management, N{\"u}rnberg}, booktitle = {PCIM Europe 2017 - International Exhibition and Conference for Power Electronics, Intelligent Motion, Renewable Energy and Energy Management, N{\"u}rnberg}, year = {2017}, abstract = {A hybrid current and acceleration control is presented and shown to improve the load disturbance behavior of servo drives significantly without additional sensor effort. The feedback signal of the acceleration control loop is calculated from the position data of the motor encoder. Hence, position measuring errors influence this control loop and lead to speed ripple. Therefore, the presented design of the acceleration control loop considers both load sensitivity and position measuring errors.}, language = {en} } @inproceedings{StubenrauchWittmannKiermayeretal.2017, author = {Stubenrauch, Franz and Wittmann, Josef and Kiermayer, Alexander and Seliger, Norbert and Hagl, Rainer and Schmitt-Landsiedel, Doris and Kennel, Ralph}, title = {FPGA-based High Dynamic Servo Drive Control with a 200kHz Gallium Nitride Inverter}, series = {2017 19th European Conference on Power Electronics and Applications (EPE'17 ECCE Europe), Warsaw, Poland}, booktitle = {2017 19th European Conference on Power Electronics and Applications (EPE'17 ECCE Europe), Warsaw, Poland}, year = {2017}, abstract = {Increased productivity in industrial processes can be achieved by dynamic and accurate positioning of servo drives. Therefore, improvement of servo drive dynamics using latest technologies in the key components such as inverter, control system and position measuring device are investigated. Using Gallium Nitride (GaN) or Silicon Carbide (SiC) semiconductors for motor inverters enables energy efficient operation up to pulse width modulation (PWM) frequencies of 500 kHz. This allows motor filters with small component sizes. As a result, high motor efficiency, low torque ripple, high control bandwidth and almost ideal sinusoidal output voltages are achieved. Experiments on a 200 kHz Gallium Nitride inverter with sine wave motor filter show a current control loop bandwidth of 3.2 kHz and almost ideal sinusoidal phase voltages. The achieved bandwidths of the speed and position control loops are 318 Hz and 106 Hz, respectively.}, language = {en} } @inproceedings{HoellthalerHaglKennel2019, author = {H{\"o}llthaler, Julia and Hagl, Rainer and Kennel, Ralph}, title = {Bandwidth Improvements of Linear Direct Drives with a 100 kHz PWM-Frequency}, series = {2019 12th International Symposium on Linear Drives for Industry Applications (LDIA), Neuchatel, Switzerland}, booktitle = {2019 12th International Symposium on Linear Drives for Industry Applications (LDIA), Neuchatel, Switzerland}, year = {2019}, abstract = {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.}, language = {en} } @inproceedings{HoellthalerHaglKennel2019, author = {H{\"o}llthaler, Julia and Hagl, Rainer and Kennel, Ralph}, title = {Bandwidth Improvements for Current Control Loops with a 100 kHz PWM Frequency and GaN Power Semiconductors}, series = {2019 58th Annual Conference of the Society of Instrument and Control Engineers of Japan (SICE), Hiroshima, Japan}, booktitle = {2019 58th Annual Conference of the Society of Instrument and Control Engineers of Japan (SICE), Hiroshima, Japan}, year = {2019}, abstract = {A discrete-time design method for a robust current controller of a servo drive has been developed. It takes the sampling time, the processing dead time and the dynamic behavior of the A/D converter into account. The theoretical calculations are verified using a test stand for high dynamics. The test stand includes a voice coil motor and power electronics with Gallium Nitride (GaN) power semiconductors for switching frequencies of more than 100 kHz. The bandwidth of the current control loop can be improved from typically 1 kHz to 1.5 kHz with insulated-gate bipolar transistor (IGBT) power semiconductors in state-of-the-art motion control systems to 10 kHz and more.}, language = {en} } @inproceedings{HoellthalerHaglKennel2020, author = {H{\"o}llthaler, Julia and Hagl, Rainer and Kennel, Ralph}, title = {Influence of the PWM Frequency on Dynamic and Position Stability of Servo Drives}, series = {25th International Symposium on Power Electronics, Electrical Drives, Automation and Motion (SPEEDAM), Virtual Meeting}, booktitle = {25th International Symposium on Power Electronics, Electrical Drives, Automation and Motion (SPEEDAM), Virtual Meeting}, year = {2020}, abstract = {The dynamic behavior and position stability of servo drives are influenced by many parameters. One major influencing parameter is the pulse width modulation (PWM) frequency. With inverters based on wide bandgap semiconductors, the PWM frequency can be increased. This enables a substantial increase in the current control bandwidth. The paper focuses on the influence of the PWM frequency on the dynamics of control loops and position stability, which are derived from theoretical correlations. The theory is verified using a test bench for high dynamic and position stability. The test bench is equipped with a voice coil motor and power electronic with gallium nitride (GaN) power semiconductors for switching frequencies of 100kHz and over. The achieved position stability, measured with a laser-based comparator at the tool center point, is lower than "+-1nm" with a standard deviation of "0.16nm" at a PWM frequency of "f_PWM=100kHz".}, language = {en} } @inproceedings{DechantSeligerKennel2019, author = {Dechant, Eduard and Seliger, Norbert and Kennel, Ralph}, title = {Performance of a GaN Half Bridge Switching Cell with Substrate Integrated Chips}, series = {PCIM Europe 2019 - International Exhibition and Conference for Power Electronics, Intelligent Motion, Renewable Energy and Energy Management, N{\"u}rnberg}, booktitle = {PCIM Europe 2019 - International Exhibition and Conference for Power Electronics, Intelligent Motion, Renewable Energy and Energy Management, N{\"u}rnberg}, pages = {7}, year = {2019}, abstract = {Wide-bandgap semiconductors such as Silicon Carbide (SiC) or Gallium Nitride (GaN) enable fast switching and high switching frequencies of power electronics. However, this potential can not be exploited due to limitations caused by parasitic elements of packaging and interconnections. This paper shows a possibility to minimize parasitic elements of a half-bridge switching cell with 650 V GaN dies integrated into a printed circuit substrate. A sub-nH commutation loop of 0.5 nH inductance gives superior switching characteristics compared to circuits with packaged dies. Simulation and experimental results of an inverse double pulse test confirm our expectations. This study further reveals additional benefits of the proposed technology in terms of mechanical stability and thermal interfacing to heat sinks compared to circuits with packaged dies.}, language = {en} } @inproceedings{DechantSeligerKennel2019, author = {Dechant, Eduard and Seliger, Norbert and Kennel, Ralph}, title = {A study of dielectric breakdown of a half-bridge switching cell with substrate integrated 650V GaN dies}, series = {2019 IEEE International Workshop on Integrated Power Packaging (IWIPP), Toulouse, France}, booktitle = {2019 IEEE International Workshop on Integrated Power Packaging (IWIPP), Toulouse, France}, year = {2019}, abstract = {This paper proposes an ultra-low inductance half-bridge switching cell with substrate integrated 650V GaN bare dies. A vertical parallel-plate waveguide structure with 100 μm layer thickness results in a commutation loop inductance of 0.5 nH resulting in a negligible drain-source voltage overshoot in the inductive load standard pulse test. On the other hand reliable circuit operation requires an assessment of the isolation strength of the thin dielectric layer in the main commutation loop, because critical high local electric fields might occur between the pads. Measurements of the dielectric breakdown voltage followed by a statistical failure analysis provide a characteristic life of 14.7 kV and a 10\% quantile of 13.5kV in the Weibull fitted data. This characteristic life depends strongly on the ambient temperature and drops to 4.1kV at 125°C. Additionally, ageing tests show an increasing in dielectric breakdown voltage after 500h, 1000h and 2000h at 125°C high-temperature storage due to resin densification processes.}, language = {en} } @article{DechantSeligerKennel2019, author = {Dechant, Eduard and Seliger, Norbert and Kennel, Ralph}, title = {Power cycling and temperature endurance test of a GaN switching cell with substrate integrated chips}, series = {Microelectronics Reliability}, volume = {100-101}, journal = {Microelectronics Reliability}, pages = {113372}, year = {2019}, abstract = {We present a reliability study of a half-bridge switching cell with substrate integrated 650 V GaN HEMTs. Power Cycling Testing with a ΔTj of 100 K has revealed thermo-mechanically induced failures of contact vias after more than 220 kcycles. The via failure mode of contact opening is confirmed by reverse-bias pulsed IV-measurements to be primarily triggered by a ΔTj imposed thermal gradient and not by a high Tj. The chip electrical characteristics, however, remained unaffected during Power Cycling. Furthermore, a High Temperature Storage test at 125 °C for 5000 h has shown no changes in the electrical performance of substrate integrated GaN HEMTs.}, language = {en} } @inproceedings{SeligerDechantBrendeletal.2020, author = {Seliger, Norbert and Dechant, Eduard and Brendel, Christian and Kennel, Ralph}, title = {Reduction of Common Mode EMI noise in microstrip line based commutation paths designed for sub-nH loop inductance}, series = {CIPS 2020 - 11th International Conference on Integrated Power Electronics Systems, Berlin - Virtual Meeting}, booktitle = {CIPS 2020 - 11th International Conference on Integrated Power Electronics Systems, Berlin - Virtual Meeting}, pages = {6}, year = {2020}, abstract = {We present a numerical and experimental design study for reducing conducted common mode noise for frequencies below 10MHz generated in switching cells comprising sub-nH commutation loops. Compared to conventional methods of adding external gate resistors our approach does not degrade efficiency. A parallel plate loop design (characterized by a minimum loop inductance and small board area usage) is found suboptimal in terms of conducted EMI compared to a micro-strip line loop geometry. The net ground impedance rather than the net ground inductance is found to mainly contribute to the observed EMI noise.}, language = {en} } @inproceedings{HilverkusHaglKennel2020, author = {Hilverkus, Johannes and Hagl, Rainer and Kennel, Ralph}, title = {Structural Mechanical Limitations of Dynamics of Servo Drives}, series = {25th International Symposium on Power Electronics, Electrical Drives, Automation and Motion (SPEEDAM), Virtual Meeting}, booktitle = {25th International Symposium on Power Electronics, Electrical Drives, Automation and Motion (SPEEDAM), Virtual Meeting}, pages = {11 -- 16}, year = {2020}, language = {en} } @inproceedings{DechantSeligerKennel2020, author = {Dechant, Eduard and Seliger, Norbert and Kennel, Ralph}, title = {Design of a Low Multi-Loop Inductance Three Level Neutral Point Clamped Converter with GaN HEMTs}, series = {IEEE Energy Conversion Congress and Exposition (ECCE)}, booktitle = {IEEE Energy Conversion Congress and Exposition (ECCE)}, publisher = {IEEE}, pages = {6}, year = {2020}, abstract = {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.}, language = {en} } @inproceedings{SeligerDechantKennel2022, author = {Seliger, Norbert and Dechant, Eduard and Kennel, Ralph}, title = {EMI mitigation by substrate integrated common mode filter}, series = {Proceedings of 12th International Conference on Integrated Power Electronics Systems (CIPS 2022)}, booktitle = {Proceedings of 12th International Conference on Integrated Power Electronics Systems (CIPS 2022)}, publisher = {VDE}, address = {Berlin (Germany)}, organization = {Labor f{\"u}r Leistungselektronik und EMV, TH Rosenheim}, year = {2022}, language = {en} } @inproceedings{DechantSeligerKennel2022, author = {Dechant, Eduard and Seliger, Norbert and Kennel, Ralph}, title = {Common Mode DGS EMI Filter Integrated into a GaN Half Bridge Switching Cell}, series = {Procceedings International Exhibition and Conference for Power Electronics, Intelligent Motion, Renewable Energy and Energy Management (PCIM 2022)}, booktitle = {Procceedings International Exhibition and Conference for Power Electronics, Intelligent Motion, Renewable Energy and Energy Management (PCIM 2022)}, publisher = {Mesago}, organization = {Labor f{\"u}r Leistungselektronik und EMV, TH Rosenheim}, pages = {6}, year = {2022}, language = {en} } @inproceedings{HilverkusMarklHagletal.2021, author = {Hilverkus, Johannes and Markl, Markus and Hagl, Rainer and Kennel, Ralph}, title = {Influence of Frequency Dependent Motor Resistance and Inductance on the Current Control Loop Design of Servo Drives}, series = {2021 IEEE 30th International Symposium on Industrial Electronics (ISIE)}, booktitle = {2021 IEEE 30th International Symposium on Industrial Electronics (ISIE)}, doi = {10.1109/ISIE45552.2021.9576370}, pages = {1 -- 7}, year = {2021}, abstract = {Servo drives in production machines are either position-, speed-, force- or torque-controlled. As the motor current is proportional to torque or force, the current control loop dynamics is crucial for all operating modes. In production machines used in the semiconductor industry, it is particularly important that the bandwidths of the control loops are continuously increased. It is thus important to take the dependency of motor resistance and inductance on frequency in control loop design into consideration. As the switching frequencies of wide-bandgap semiconductors increase, the effect becomes even more significant. This paper discusses the influence of frequency-dependent resistance and inductance on the behavior of a PI current controller. A design method for an optimized and robust current controller is then presented on this basis. Verification is performed with two completely different servo motors-a 3-phase permanent magnet synchronous motor and a high-dynamic optimized voice-coil motor.}, language = {en} }