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EPE 2021 - Dialogue session - Measurement, Supervision and Control for Power Converters
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2021 ECCE Europe - Conference > EPE 2021 - Topic 04: Electrical Machines and Drive Systems > EPE 2021 - Dialogue session - Measurement, Supervision and Control for Power Converters
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	A Comparison of Vibrations on the Induction Motor driven by Inverter   By Yosuke AOKI	[View]   [Download]
Abstract: Various types of pulse width modulation (PWM) schemes have been proposed to drive three-phase voltage-fed inverters (voltage source inverters). Among them, the two-phase PWM scheme can achieve relatively higher AC voltage, lower switching times and lower switching loss than the threephase PWM scheme. However, the two-phase PWM scheme has a disadvantage that the harmonics in the AC line voltage and current are distributed over a wide frequency range. This paper compares the vibrations generated in induction motors driven by three-phase voltage-fed inverters with various PWM schemes.
	A Measurement-Based Method for Characterizing Parasitic Inductances in Power Electronic Circuits   By Mohsen ASOODAR	[View]   [Download]
Abstract: This paper presents a new method of measuring parasitic inductances in various elements of power electronic circuits. The proposed solution features a low-cost design while providing accurate measurement results in a prede_ned range of stray inductances. The solution utilizes a unique parallel resonance circuit for extracting stray inductances in various circuits. Structural challenges as well as the analysis for the choice of circuit parameters are addressed in this study. Both simulation and experimental results are presented to exhibit the ef_cacy of the solution. Moreover, important design constraints that can affect the end results are explained and considered in the proposed experimental setup.
	A novel approach of torque ripple estimation by inverter induced current slope evaluation for interior permanent magnet synchronous machines   By Philipp DEGEL	[View]   [Download]
Abstract: The following work describes a new method for estimating the torque ripples of an interior permanent magnet synchronous machine (IPMSM) by estimating the machine parameters within one PWM cycle using the current slopes caused by the switching of the inverter. The use of test signals and filter-based approaches is avoided. In the first paragraph the state-of-the-art torque estimation algorithms are presented and the difference to the new method explained. Following, the theory of the torque equation is derived and the solution of this equation under the consideration of the different switching states of the inverter is investigated. Finally, all presented theoretical results are validated with measurement results on the test bench.
	A novel soft-start and -stop procedure for current-fed dual active bridge   By Tuan Anh DO	[View]   [Download]
Abstract: This paper focuses on the control issues of Current-Fed Dual Active Bridge (CFDAB) converters. The Dual PWM plus double phase-shifted (DPDPS) modulation is applied for the converter due to its considerable advantages. A new method for soft-start and soft-stop in control design in boost mode is presented in this paper, which is validated by experimental tests of a 2.5kW prototype CFDAB converter. The results show the successful soft-start operation as well as the good system performance, that proves the feasibility and effectiveness of the proposed control method.
	A Simplified Technique for Estimating the Filter- and Grid-Impedances for VSIs Connected to the Grid via L-Filter   By Gyanendra Kumar SAH	[View]   [Download]
Abstract: This work proposes a simplified online parameter estimation technique for the filter and grid impedances for VSIs connected to the grid via an L-filter and compares the results with the standard estimating methods. The measured L-filter parameters extracted via an LCR meter and the manufacture's datasheet are limited in accuracy since they ignore the switching behavior of the PWM-based VSIs. These methods neglect second-order effects such as the skin effect and hysteresis losses. The proposed parameter estimation technique is straightforward and does not require an additional change in the existing hardware. Further, the estimated filter parameters also include the losses present in the switches and the magnetic cores. Open-loop and Command Tracking (CT) plots of both hardware and simulation are used to validate, analyze, and compare the studied concepts. The proposed online parameter estimation technique is found to be superior compared to the studied parameter estimation techniques.
	Advanced DC-charging Methods for Traction Drives with Dual Two-Level Inverter During Machine Operation   By Johannes BUEDEL	[View]   [Download]
Abstract: This paper aims to present a concept and especially developed control methods for an open-end winding traction drive, powered by a dual two-level inverter, where the two separate energy sources can be charged via a DC grid during operation and while being standstill. For achieving a high quality DC-current, the parasitic Back-EMF harmonics of the electrical machine will be compensated. The application aims to achieve high utilisation of the electric vehicle in combination with a partly equipped trolley wire net.
	Contact-integrated temperature measurement for power modules   By Sören FRÖHLING	[View]   [Download]
Abstract: Negative Temperature Coefficient (NTC) sensors in power modules are used for temperature measurement and often located at the edge of the module due to the isolation constraints. This paper focusses on connecting a physical temperature sensor in parallel to the IGBT gate and auxiliary emitter contacts in order to mount the sensor directly onto an IGBT chip, without requiring an additional isolation.
	Dynamic Operation of Buck-Boost DC-DC Converters over Wide Operating Ranges with Switching Based Model Predictive Control (MPC)   By Min JEONG	[View]   [Download]
Abstract: In this paper, a novel model predictive control (MPC) scheme is proposed for buck-boost converters for achieving a high control bandwidth over wide operating ranges. There, the duty cycles of the four possible switching states are considered as control inputs, such that an exact state propagation can be accurately predicted in a large-signal linear model. Unlike conventional methods, which suffer from poor dynamic control performance when the input voltage is close to the output voltage, the proposed method achieves good dynamic and steady-state control performance independent of the operating point by actively utilizing all four switches during transients and switching only two switches during the steady-state. The resulting quadratic programming (QP) problem enables a real-time implementation of the proposed MPC method at a fast sampling rate.
	Fault Detection using Indirect DC Link Current Measurement Technique in Multiphase DC Converter with Coupled Inductor   By Arturs BOGDANOVS	[View]   [Download]
Abstract: Here, an indirect DC link current measurement technique is proposed and evaluated in terms of fault detection capability in multiphase converter with highly magnetically coupled inductor and distributed DC link capacitors. The indirect DC link current sensing circuit parameter modification is introduced and the measurement accuracy improvements are assessed in comparison with previously proposed results. A novel approach for converter typical fault detection and identification uses the idea, that the DC link current waveforms are acquired using converter switching functions and hence, reflect the occurring switch faults. Most common converter failure modes are acquired experimentally to analyze their influence on the DC link current waveforms and assess their detection capabilities. The derived fault detection algorithms are verified under different converter operating conditions by evaluating the time needed for failure identification. The proposed method shows adequate phase current measurement accuracy and fault identification capabilities within a reasonable timeframe; therefore, it can be used for current balancing controller implementation, diagnostic purposes and further design of converter fault-tolerant operation modes.
	High-Frequency Inductor Current Estimator for Power Converters   By Bart BOKMANS	[View]   [Download]
Abstract: A method is proposed to estimate the high-frequency inductor current in a half-bridge circuit. Modern wide-bandgap semiconductors such as GaN allow for multi-megahertz switching frequencies. As a result, the frequency content of the inductor current also increases. The conversion delay of an analog-to-digital converter results in a difference between the measured and instantaneous inductor current, especially when the current slope exceeds tenths of milliamps per nanosecond. To overcome this problem, the inductor current is estimated on a digital controller in real-time and the output voltage and current are used for feedback purposes. A slower closed-loop reduced-order observer is developed and extended with an extrapolator to calculate the inter-sample response at a very high frequency. The closed-loop reduced-order observer uses the difference between the measured and estimated output voltage and consequently ensures robustness for model inaccuracies and non-linearities present in the power converter. The extrapolator is running in open-loop but uses the calculated error during the previous update cycle of the closed-loop observer. The proposed estimator is tested in simulation and verified on a field programmable gate array (FPGA). Both the reduced-order closed-loop observer and open-loop extrapolator are merged into a single block to minimize the computational effort in the FPGA.
	Hysteresis Current Control for a High Efficiency 3ch-Interleaved Totem Pole PFC in Triangular Current Mode   By Marco TORRISI	[View]   [Download]
Abstract: In this paper, an effective Hysteresis Current Control implemented in a Totem Pole Power Factor Corrector (PFC) is presented. The Zero Voltage Switching (ZVS) technique has been adopted to boost the converter efficiency, hence a comprehensive mathematical model of the resonance transient has been developed to properly set the ZVS transitions. The proposed control scheme and transient model have been simulated in MATLAB/Simulink environment and implemented on STMicroelectronics microcontroller STM32G474. Finally, experimental results of a prototype are presented validating the concept, the adopted model and the implementation.
	Impact of Conduction Mode and Phase-Shedding Strategy on Transistor Lifetime in Building-Integrated Photovoltaics Module-Level Converters   By Simon RAVYTS	[View]   [Download]
Abstract: In this paper, the impact of control on lifetime and efficiency will be investigated for the case of an interleaved boost converter. Firstly, the influence of the conduction mode on losses and start-up current will be discussed. Secondly, two possible phase shedding strategies will be discussed and compared to the case where all phases are continuously on. A new temperature based phase shedding scheme is introduced for applications where high temperatures occur, such as in BIPV applications. Six different combinations of conduction mode and phase shedding strategy are combined in a simulation framework. The cases are evaluated on efficiency and lifetime using one-year experimental data of a BIPV test building.
	Impact of PWM Techniques in Efficiency and Power Density of a 70kVA Multilevel Inverter for More Electric Aircrafts   By Hans HOFFMANN SATHLER	[View]   [Download]
Abstract: This paper proposes an optimization technique for weight reduction in the flying capacitor and output inductors of a 7-level inverter composed of three 3-level legs connected in parallel per phase. The target application belongs to the aircraft domain, which demands weight reductions as it is related to the aircraft operating costs. The optimized techniques proposed in this paper are named FCPWM (Flying Capacitor Pulse Width Modulation Technique) and ILPWM (Output inductors Pulse Width Modulation Technique), achieved through simulation, up to 17 \% and 37 \% on weight reduction, for the flying capacitors and output inductor, respectively. Those values are calculated considering the same modulation index and power factor and comparing the optimized techniques to the sinusoidal PWM technique. Several PWM techniques are compared with the optimized ones and are validated by experimental results that confirm these reductions. For lower current ripple application (IL = 35 \% and VFC = 5 \%), in the given conditions, ILPWM reaches the best results of power density and efficiency (8.30 kW/kg and 98.94 \%) compared to the traditional continuous and discontinuous methods, for example, 7.01 kW/kg and 98.76 \% for the SPWM and 7.54 kW/kg and 98.88 \% for the DPWM3.
	Implementation of a Long-Horizon Model Predictive Control Algorithm on an Embedded System   By Eyke LIEGMANN	[View]   [Download]
Abstract: This paper deals with the implementation of a long-horizon finite control set model predictive control (FCS-MPC) algorithm on an embedded system. The targeted application is a medium voltage drive system implying a very low switching frequency. The implementation is facilitated by the use of a high level synthesis (HLS) tool, which synthesizes C++ code into VHDL, enabling a higher level of abstraction and faster prototype development. Experimental results based on a small-scale prototype, consisting of a three-level neutral point clamped (NPC) inverter and an induction machine, confirm that the algorithm can be executed in real time within the targeted control period of 25us. This allows for high switching granularity, and thus favorable steady-state and transient performance.
	Improvement of Modified Trapezoidal Modulation Signal using Vector Topology   By Yasuhiro FUKUI	[View]   [Download]
Abstract: In this paper, we focus on motor control with matrix converters using Modified Trapezoidal Modulation (MTM). MTM can reduce the 6th harmonic of the motor. Furthermore, the fundamental wave amplitude can be increased. This advantage is used to overcome the low voltage utilization of matrix converters. In this paper, the output waveform of the matrix converter is changed to MTM. The simulation software (PSIM) was used to verify the d-axis current, q-axis current, and revolutions per minute (rpm). The results show that it is possible to apply the MTM to the matrix converter.
	Investigation of the modulation index tuning advantages for voltage source inverters with adjustable DC-bus voltage   By Antoine SABRIÉ	[View]   [Download]
Abstract: This paper demonstrates that the possibility to regulate the modulation index of the Pulse-Width Modulation (PWM) scheme by adjusting the DC bus voltage could improve the Voltage Source Inverter (VSI) performances by improving THD of the phase voltages, reducing the temperature of the DC link capacitors, increasing the efficiency and decreasing the impact of the dead-times distortions. Theoretical derivations are validated experimentally on inductive load as well as on permanent magnet synchronous machine.
	Model Predictive Control and the Selection of Cost Functions   By Diego ROJAS	[View]   [Download]
Abstract: In model predictive control strategy implementations, the cost function selection is very important inensuring good performance. In this paper a study of the most common cost functions used for the control of two level voltage source inverters is presented. The paper compares several cost function alternatives that could be considered for different power electronic converter applications. The results show that Model Predictive Control is a suitable alternative for the implementation of different control objectives in power converters and show how to find the best balance in the cost function.
	Modelling and Design Optimisation of a High Bandwidth and High Precision Optical Current Sensor Based on the Faraday Effect   By Stefan RIETMANN	[View]   [Download]
Abstract: A magneto-optical current measurement system based on the Faraday effect is evaluated for measuring fast pulse currents in high power applications. The current measurement system is based on the interaction of the magnetic field, generated by the current, and a beam of light propagating through magneto-optical material which is in close proximity to the current conductor. A high local magnetic field per ampère current inside the optical path is required to improve the accuracy and the sensitivity of the optical current measurement sensor.In this paper, the relation between the conductor geometry and the local magnetic field distribution isanalytically modelled resulting in the geometry factor Kg . The analytical model enables an optimisation of the busbar geometry to increase the overall probe sensitivity and the accuracy of the optical current measurement system.
	Modulation Method to Reduce Losses in Inverters with LC-Filters   By Benedikt KOHLHEPP	[View]   [Download]
Abstract: As high efficiency is a crucial parameter for inverters, this paper proposes a modulation method to reduce rms currents and current ripple in inverters with LC output filter. Operating an inverter with a fixed switching frequency, a sinusoidal current with a superimposed triangular current ripple results in the filter inductance. Using the proposed modulation scheme reduces the rms current of the filter inductance by reducing the current ripple with an increased switching frequency. The switching frequency is only increased in the range where ZVS can be achieved for both half-bridge switches. During this time the switching losses can be neglected. Thus, the novel modulation scheme reduces conduction power losses in semiconductors, filter inductance, and capacitors.
	Multi-Parameter Identification by Exploiting Module Parasitics With Only One Sensor   By Frank LAUTNER	[View]   [Download]
Abstract: In this study, a low cost current sensing approach based on module parasitics (inductances and resistances) is examined. It was found that the best results are achieved by using an active low pass filter as sensor element for the typical inductive-resistive measurement sections. This procedure, however, bears the drawback that the resulting sensor signal is highly dependent on other influencing parameters, especially module temperature and load current transient in the to-be-measured current pulse. To compensate these effects, this paper examines the origin of the sensor signal in detail and shows interesting results: It could be found that the information for current and the influencing parameters is embedded in the sensor signal waveform. This circumstance can be exploited by special sensor low pass time constants and an adapted sampling scheme of this signal. The samples can be processed to analyse the influencing parameters as well as the module current. In the following, considerations are given for different processing approaches including the application of an artificial neural network (ANN). This method is also tested in a close to reality simulative situation to proof the concept. It could be shown that the mathematical designed approach works and gives the first opportunity for a module parasitic current sensing approach without disturbance by temperature.
	Nanoscale observation of the power semiconductor devices by scanning capacitance force microscopy and its device simulation   By Nobuo SATOH	[View]   [Download]
Abstract: We have observed in the nanoscale of the power semiconductor device under the bias voltage applied using by the scanning probe microscope based on combined with AFM/KFM/SCFM that achieved high spatial-resolution and high sensitivity. Based on the observed results, numerically analyse as device simulation were also presented.
	Online identification of semiconductor switching times in inverters with inductive load using field programmable gate arrays   By Stefan HÄHNLEIN	[View]   [Download]
Abstract: The nonlinear behavior of inverters is mainly influenced by the interlocking and switching times of the semiconductors. In the following work, a method is presented that enables the possibility of an online identification of the switching times of the semiconductors. This information allows a compensation of the non-linear behavior, a reduction of the locking time and can be used for diagnostic purposes.First, a theoretical derivation of the method is made by considering different cases when switching of the inverter and deriving identification possibilities. The method is then extended so that the entire module is taken into account. Furthermore, a possible theoretical implementation is shown. After the methodology has been investigated with possible limitations, boundary conditions and with respect to real hardware, an implementation in the FPGA is performed. Finally, the results are presented, discussed and further improvements are presented in an outlook.
	Overview of Methods for Battery Lifetime Extension   By Siyu JIN	[View]   [Download]
Abstract: Lithium-ion (Li-ion) batteries are widely used in transportation, aerospace, and electrical. How to extend their lifetime has become an important topic. In this paper, the methods for battery lifetime extension in terms of thermal management, charging/discharging optimization, and power and energy management control strategies are reviewed. Firstly, this paper summarizes and classifies the methods proposed in recent years to extend battery lifetime. Secondly, the advantages and drawbacks of each method are compared in detail. Finally, the advancement of various methods is summarized and prospect for future research direction on battery lifetime extension is provided.
	PN admittance characterisation of grid supporting VSC controllers with negative sequence regulation and inertia emulation   By Callum HENDERSON	[View]   [Download]
Abstract: This work presents an analysis of converter output admittance for grid supporting VSC controllers in the positive - negative frame (pn-frame). Previously discovered issues in other reference frames are explored to prove the efficacy of analysis in the pn-frame The effect of negative sequence control is often overlooked and the pn-frame offers a useful method for observing the result. The impact of control parameters such as PLL bandwidth was explored which decreased network damping and increased regions of negative incremental impedance. Reduction of unwanted admittance components was achieved by the addition of appropriately tuned voltage feedforward filters. The equivalence of inertia and droops has been documented previously but not utilising converter impedance. Analogous traces of impedances were obtained for each structure with a similar response obtained when changing the respective associated gain indicating an equivalence.
	Robust Control Architecture For Waste Heat Harvesting With Non-Inverting Buck-Boost Converter   By Pierpaolo SORBELLINI	[View]   [Download]
Abstract: Thermoelectric generators (TEG) can be used to harvest wasted heat. TEGs are characterized by a wide output voltage range and a considerable output resistance leading to a maximum power point dependent on the working temperature. Non-Inverting Buck-Boost converter is used to manage, from one side, the wide voltage range, and from the other a battery. This article investigates a robust control architecture to recover the maximum energy from the exhaust's heat avoiding instability issues and maximizing converter efficiency.
	Temperature Considerations for Online Health Monitoring of DC-Link Capacitors in Modular Multilevel Converters   By Mohsen ASOODAR	[View]   [Download]
Abstract: In this paper, the effect of temperature on online heath monitoring of dc capacitors in modular multilevel converters (MMCs) is studied. The submodule capacitance value is considered as the main indicator of health. Both self heating and ambient temperature are considered as sources of temperature variation. The study is conducted on a single phase MMC with full-bridge submodules. However, a similar analysis can be used for half-bridge MMCs and multiphase MMCs as well. The thermal behaviour of the capacitors is explained analytically and simulated using a simplified Cauer model. The effect of temperature on the estimated capacitance values is shown, and a method for reducing this effect is proposed. The results are verified using simulations in MATLAB/Simulink.
	Unified Frequency Adaptive Filter for Both Single- and Three- Phase Utilization with Multi- Complex Resonators   By Wu CAO	[View]   [Download]
Abstract: To fast extract zero-steady-state error of fundamental frequency positive sequence, this paperproposes a unified frequency adaptive filter for single and three phase with multi complexresonators. The structure and principle of this filter are illustrated. The property of proposed filteris analyzed. Simulation results are provided to verify the effectiveness.
	Varying phase-shift carriers pulse-width modulation for cascaded H-bridges with improved line-to-line voltage   By Juhamatti KORHONEN	[View]   [Download]
Abstract: Cascaded H-bridges has been proven to be a suitable topology for high-power drives applications. The modular structure and high output power quality make the topology appealing in various applications, especially in medium voltage drives. This paper introduces an improved phase-shifted carriers pulse-width modulation (PWM) method that is able to produce enhanced line-to-line voltage waveform over the conventional phase-shifted carriers PWM. The proposed method uses interleaving among the H-bridge cells, which allows symmetric loading and increased apparent switching frequency. The proposed method varies the phase-shift of the carriers based on the voltage reference, allowing a smooth line-to-line voltage waveform. The modulation method is simulated with a 2.3 kV five-level cascaded H-bridge inverter.
	Voltage and Current Control for Single-Phase Inverter with LCL and LCLC filters   By Diego F. SENDOYA-LOSADA	[View]   [Download]
Abstract: Nowadays, current-controlled methods (CCM) are widely used to improve the performance of DC-AC converters in distributed generation (DG) units connected to the power distribution system. However, serious stability problems can occur when this unit switches to an operation mode off-grid. In this situation, it is preferred to change the control mode of DG units to a voltage-controlled method (VCM). This paper proposes an improved method to control, in a coordinated way, the voltage and current supplied by a single-phase inverter. When the inverter operates in tied-grid mode, an LCL filter is used to reduce the harmonic content of the current. On the other hand, when the inverter operates in islanding mode, an LCLC filter reduces the harmonic content of the voltage. For each operation mode, a Proportional-Integral (PI) controller is designed using the Robust Loop Shaping (RLS) method. The DG unit using the proposed method can be switched between tied-grid and islanding modes at any time, maintaining the quality of the supplied electrical power. Simulated results are provided to verify the feasibility of the proposed approach.
	Wide Bandwidth Current Sensor for Characterization of High Current Power Semiconductor Modules   By Philipp ZIEGLER	[View]   [Download]
Abstract: This paper presents a current sensor for commutation current measurement of high current powersemiconductor modules with a bandwidth from DC up to 240 MHz. It is integrated in the commutationpath with a coaxial housing generating a specified measurement point adding a low insertion inductanceof 1.8 nH. It consists of tunnel-magnetoresistance sensors for low frequency current measurement anda PCB integrated Rogowski coil for high frequency current measurement. The measurement techniquesare combined using the HOKA principle. The DC current linearity, the dynamic behavior as well as thesignal-to-noise ratio of the current sensor is characterized.