Table of contents monday, September 9, 1: 30pm-4: 00pm modular Multi-Level Converters, hvdc, and dc grids I 3
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- Bu səhifədəki naviqasiya:
- Modeling and Control of Resonant Converters
- Electric Machines for Automotive Applications I
- PM Machines II
- Multilevel Motor Drives
- PM and IPM Motor Drives III
| 11:45AM Three-Phase Four-Wire AC-DC-AC Multilevel Topologies Obtained from an Interconnection of Three-leg Converters [#1146]
Ayslan Caisson Noroes Maia, Cursino Brandao Jacobina, Nayara Brandao de Freitas, Antonio de Paula Dias Queiroz and Edison Roberto Cabral da Silva, Federal University of Campina Grande, Brazil This paper investigates three AC-DC-AC multilevel topologies for three-phase four-wire (3P4W) applications obtained from an interconnection of three-leg voltage source converters (VSCs). The topologies provide bidirectional power flow and can be applied in line voltage regulators, universal active power filters and uninterrupted power supplies (UPS). Operating principles, a pulse-width modulation (PWM) technique and an overall control strategy are developed. The PWM and control strategies are suitable to regulate the DC-link voltage and to optimize the harmonic distortion, reducing switching stress and power losses. Simulation results are used to compare the proposed configuration with a conventional solution in terms of harmonic distortion and semiconductor losses. Experimental results are presented to validate the theoretical considerations and were obtained by using IGBTs with dedicated drives and a digital signal processor (DSP) with appropriated plug-in boards and sensors. Modeling and Control of Resonant Converters Wednesday, September 21, 10:30AM-12:10PM, Room: 102C, Chair: Rolando Burgos, Marko Hinkkanen 10:30AM Extreme Start-Up Response of LLC Converters Using Average Geometric Control [#1322] Mehdi Mohammadi and Martin Ordonez, University of British Columbia, Canada Resonant power converters have become ubiquitous to efficiently process electrical energy, however, their complicated structure challenges linear controllers in anticipating their large signal performance. Since small- signal modeling techniques do not provide sufficient information regarding the large signal behavior of power converters, nonlinear geometric controllers can be employed to tackle the poor large signal dynamic response. In this paper, a nonlinear controller called the average geometric controller is introduced for the LLC converter with the ability of providing an extreme start-up dynamic response and eliminate overshoot. A novel average large signal model is developed and serves as the foundations to develop the average geometric controller for LLC converters. The average large signal model significantly simplifies the large-signal behavior analysis and results in obtaining the average circular trajectories of the LLC converter. In order to validate the theoretical analysis, experimental and simulation results of a 500W prototype LLC converter employing the average geometric controller are presented. The experimental results show a significant increase in start-up performance while the overshoot is eliminated. 10:55AM Optimized Resonant Pulsed Power Supplies with Deadbeat - Repetitive Regulation [#758]
This paper presents a novel digital deadbeat + repetitive control (DBRC) strategy for output voltage regulation of pulsed power resonant converters used in high energy physics applications. The proposed converter contains three individual series resonant parallel loaded (SRPL) converter arms, which effectively mitigate the influence of resonant tank unbalances on the converter operation. The deadbeat controller is designed to produce fast dynamics of the voltage pulses during the system transient periods, while the repetitive controller is employed to counteract model uncertainties and component variations and hence to achieve a high performance and fine quality in the steady state. 11:20AM Control and Operation of Medium-voltage High-power Bi-directional Resonant DC-DC Converters in Shipboard DC Distribution Systems [#1481]
Shipboard power system is moving towards more insertion of medium voltage (MV) dc sub-system in the existing MVAC power system. Isolated bidirectional dc-dc converter, analogous to a dc energy router, is one of the key enabling components in such a MVDC system to inter-tie different dc buses with the capability of power flow control as well as fault isolation. Control of such converters in medium voltage and high power scale is always a challenge to ensure fast power flow dynamic response and high efficient operation. In this paper, a variable frequency and phase-shift control solution is presented to regulate the bi-directional power flow in a 1kV to 5kV MW-class LLC resonant converter. The proposed method achieves soft-switching on all power devices across the entire power range as well as seamless power direction change. In addition, a system level control is implemented to fulfill the multifunctional operations in the shipboard applications. Both the hardware-in-loop (HIL) test and the hardware test results are presented. 11:45AM Inductance Cancellation in RF Resonant Power Converters [#687]
Parasitic inductance cancellation is employed in order to operate a resonant power inverter at 27.12 MHz using a TO-220 through-hole package. A Cauer-type 1 LC network permits the coupling of inductors to achieve cancellation of multiple parasitic inductances and reduces semiconductor device stress in the same way as the Phi2 inverter topology. The elimination of parasitic inductances allows for system cost reduction, increased power handling, and/or relaxation of PCB layout constraints. The inductance cancellation technique is demonstrated through two prototypes (based upon the same silicon MOSFET die) providing 60 W of RF power to a 50-ohm load from a 48 V DC input: one prototype utilizes a small surface-mount package, and another a larger through-hole TO-220 package. (Without inductance cancellation, the lead inductance of the TO-220 is too large and cannot be used in a 27.12 MHz resonant application.) Inductance cancellation was verified through comparing impedances, operating waveforms, and efficiencies between the prototypes with different MOSFET packages. Electric Machines for Automotive Applications I Wednesday, September 21, 10:30AM-12:10PM, Room: 102B, Chair: Thomas Jahns, Sinisa Jurkovic 10:30AM Retrospective of Electric Machines for EV and HEV Traction Applications at General Motors [#1387] Khwaja Rahman, Sinisa Jurkovic, Peter Savagian, Nitinkumar Patel and Robert Dawsey, General Motors, United States This paper presents a retrospective of electric motor developments in General Motors (GM) for electric vehicle (EV), hybrid electric vehicle (HEV), plug-in hybrid electric vehicle (PHEV), and fuel cell electric vehicle (FCEV) production programs. This paper includes i) the progression of electric motor stator and rotor design methodologies that gradually improved motor torque, power, and efficiency performance while mitigating for noise, ii) Heavy rare earth (HRE) mitigation in subsequent design to lower cost and supply uncertainty, iii) Design techniques to lower torque ripple and radial force to mitigate noise and vibration issues. These techniques are elaborated in details with design examples, simulation and test data. 10:55AM High-Performance Partitioned-Stator Switched Flux Memory Machines with Hybrid Magnets on External Stator for Automotive Traction Applications [#1032]
This paper proposes and investigates a new topology of switched flux memory machine, in which the hybrid magnets and armature windings are separately located on external and inner stators, respectively. Due to the effective online permanent magnet (PM) magnetization, the excitation copper loss can be eliminated. Hence, the high efficiency can be maintained across a wide range of speeds and loads, which is desirable for traction applications. Meanwhile, the partitioned stator (PS) design is beneficial to the alleviation of geometric conflicts between magnetic and electric loadings. In addition, the fact that armature windings are located in the inner stator leads to the increase of effective split ratio similar to an external-rotor machine design. Consequently, the torque capability can be further improved compared to its inner-PM counterpart. The machine topologies having PMs mounted on either external or internal stator are introduced first. The design considerations for the slot/pole combination are investigated. Based on the identical basic specifications, the major electromagnetic characteristics of the optimally designed external-PM machine are investigated in comparison to those of its internal-PM counterpart. The analysis results reveal that the EPM-PS-SFMM can provide wider flux regulation range, higher torque capability as well as lower torque ripple than its IPM counterpart, which confirms the validity for the proposed design. 11:20AM Test Results for a High Temperature Non-Permanent Magnet Traction Motor [#1576]
Commercially available hybrid and electric vehicles are generally using rare earth PM motors because of their compactness and very good efficiency. But the supply security and price volatility of rare earth materials are still major concerns for the hybrid and electric vehicle industry. Hence, global efforts are underway in several countries on using reduced or non rare earth materials, developing non PM solutions and taking cost out by trading off between material properties and cost.This paper presents a high temperature DC biased reluctance machine which is structurally similar to a conventional SRM. This non PM machine has a DC field winding and an AC three phase armature winding. The machine is equipped with a high temperature 280C rated insulation system. Test results showing machine performance under continuous operation against the FreedomCar 2020 specifications as well as at high temperature up to 280C are presented. A 43 percent improvement in power density was achieved by going to high temperature. 11:45AM Vehicular Suspension and Propulsion Using Double Sided Linear Induction Machines [#971]
This paper presents a new method of combined electromagnetic levitation and propulsion using a double sided pair of linear induction machines and a simple conductive sheet secondary. If the supply phase angle of one primary is modified with respect to that of the other, a controllable lift force can be developed on the conductive secondary and its load at any velocity or when stationary. Further, a resolution force is developed tending to drive the secondary into the center of the air gap, meaning that the system is inherently self-stabilizing without complex position feedback or control. This effect is studied and predicted using finite element analysis and then measured and confirmed using an experimental rig. PM Machines II Wednesday, September 21, 10:30AM-12:10PM, Room: 101A, Chair: Siavash Pakdelian, Nicola Bianchi 10:30AM Experimental Verification of Rotor Demagnetization in a Fractional-Slot Concentrated-Winding PM Synchronous Machine under Drive Fault Conditions [#696] Gilsu Choi, Yichao Zhang and Thomas Jahns, University of Wisconsin - Madison, United States This paper presents the results of experimental tests designed to verify analytical predictions of the rotor demagnetization characteristics of a 0.6 kW 9-slot/6-pole fractional-slot concentrated winding (FSCW) interior PM (IPM) synchronous machine. The demagnetization characteristics of the rotor magnets in this commercially-produced FSCW-IPM machine are measured using a test configuration that is designed to conduct multiple demagnetization tests on the same test machine under controlled temperature conditions. In this paper, finite element predictions of the rotor demagnetization characteristics of the experimental machine during 3-phase symmetrical short-circuit (SSC) and single-phase asymmetrical short-circuit (ASC) faults are compared to experimental test measurements of the post-fault currents and the magnet flux density distribution following demagnetization, demonstrating very good agreement of many key features. This paper presents the results of experimental tests designed to verify analytical predictions of the rotor demagnetization characteristics of a 0.6 kW 9-slot/6-pole fractional-slot concentrated winding (FSCW) interior PM (IPM) synchronous machine. The demagnetization characteristics of the rotor magnets in this commercially-produced FSCW-IPM machine are measured using a test configuration that is designed to conduct multiple demagnetization tests on the same test machine under controlled temperature conditions. In this paper, finite element predictions of the rotor demagnetization characteristics of the experimental machine during 3-phase symmetrical short-circuit (SSC) and single-phase asymmetrical short-circuit (ASC) faults are compared to experimental test measurements of the post-fault currents and the magnet flux density distribution following demagnetization, demonstrating very good agreement of many key features. 10:55AM Influence of Stator Configuration on High Frequency Signal Injection Based Permanent Magnet Temperature Estimation in PMSMs [#1580]
The performance and life expectance of Permanent Magnet Synchronous Machines (PMSMs) is strongly affected by the PM temperature. An increase of the PM temperature reduces the PM strength and consequently the machine torque production capability. Also there is a risk of irreversible demagnetization if PM temperature is too high. Directly measurement of the PM temperature is not easy, PM temperature estimation methods have therefor been widely investigated during the last decade. PM temperature estimation methods can be divided into thermal models, BEMF methods and methods based on the injection of some type of test signal in the stator terminals of the machine. Thermal models require previous knowledge of the machine geometry, materials and cooling system. BEMF and high frequency signal injection methods do not require previous knowledge of the machine geometry or cooling system. However, BEMF methods require that the machine is rotating. High frequency signal injection methods can be used at any speed, including standstill. However, there is a number of issues that can affect to the accuracy of these methods, including stator and rotor designs, machine assembling tolerances and rotor lamination grain orientation. This paper analyzes the sensitivity of high frequency signal based temperature estimation methods to the stator design. 11:20AM Analysis and Design Guidelines to Mitigate Demagnetization Vulnerability in PM Synchronous Machines [#1280]
A design approach is presented to mitigate demagnetization vulnerability in permanent magnet synchronous machines (PMSMs) by proper selection and design of stator windings and rotor configurations. First, a comparative analysis of the stator demagnetizing MMFs and leakage inductances for surface PM machines equipped with integral-slot distributed windings (ISDW) and fractional-slot concentrated windings (FSCW) is performed under the constraint of equal magnet flux linkage. Finite element analysis is used to build confidence in the predicted variation of flux density over the magnet surfaces in the two machines. Overall, two convenient metrics are proposed to evaluate the relative amplitude of peak demagnetizing MMF and potential rotor temperature rise due to eddy-current losses. This study shows that the FSCW-PM machine is more vulnerable to rotor demagnetization compared to the ISDW-PM machine because of the higher peak demagnetizing MMF applied by the stator winding currents and rich spatial harmonics that increase rotor losses. 11:45AM The Nature of the Torque Ripple in Fractional-slot Synchronous PMAREL Machines [#572]
This paper deals with the analysis of average torque and torque ripple in synchronous reluctance machines assisted by Ferrite permanent magnets, for applications requiring high torque at low speed. The machines distinguish themselves by an anisotropic rotor and a high number of poles. As a peculiar feature, the analysed machines are characterized by fractional-slot non-overlapped coil windings. When anisotropic rotors are employed in stators with fractional-slot winding, there is a worsening of the torque quality: the average torque decreases and the torque ripple increases with respect to the distributed winding machines. This paper aim is to analyse the nature of the torque generation in such machines, that is, to investigate the magnetic phenomenon causing the average torque decrease and the torque ripple increase. Multilevel Motor Drives Wednesday, September 21, 10:30AM-12:10PM, Room: 101B, Chair: Luca Zarri, Yi Deng 10:30AM A Fault-Tolerant T-Type Multilevel Inverter Topology with Soft-Switching Capability Based on Si and SiC Hybrid Phase Legs [#1630] Jiangbiao He, Nathan Weise, Ramin Katebi, Lixiang Wei and Nabeel Demerdash, GE Global Research, United States; Marquette University, United States; Rockwell Automation, United States The performance of a novel three-phase four-leg fault-tolerant T-Type inverter topology is presented in this paper, which significantly improves the fault- tolerant capability of the inverter regarding device switch faults. In this new modular inverter topology, only the redundant leg is composed of SiC power devices and all other phase legs contain Si power devices. The addition of the redundant leg, not only provides fault-tolerant solution to switch faults that could occur in the T-Type inverter, but also can share load current with other phase legs. 10:55AM An On-Line Diagnostic Method for Open-Circuit Switch Faults in NPC Multilevel Converters [#1649]
On-line condition monitoring is of paramount importance for multilevel converters used in safety-critical applications. A novel on-line diagnostic method for detecting open-circuit switch faults in neutral-point-clamped multilevel converters is introduced in this paper. The principle of this method is based on monitoring the abnormal variation of the dc-bus neutral-point current in combination with the existing information on instantaneous switching states and phase currents. Advantages of this method include simpler implementation and faster detection speed compared to other existing diagnostic methods in the literature. 11:20AM Analysis of Neutral Point Deviation in 3-level NPC Converter under Unbalanced 3-phase AC Grid [#869]
This paper presents a neutral point deviation compensating control algorithm applied to a 3-level NPC converter. The neutral point deviation is analyzed with a focus on the current flowing out of or into the neutral point of the dc- link. Based on the zero sequence components of the reference voltages, this paper analyzes the neutral point deviation and balancing control for 3-level NPC converter. An analytical method is proposed to calculate the injected zero sequence voltage for neutral point balancing based on average neutral current. This paper also proposes a control scheme compensating for the neutral point deviation under generalized unbalanced grid operating conditions. The positive and negative sequence components of the pole voltages and ac input currents are employed to accurately explain the behavior of 3-level NPC converter. Simulation results are shown to verify the validity of the proposed algorithm. 11:45AM A Modulation Technique of Neutral Point Clamped Converters with Common-Mode Voltage Reduction and Neutral-Point Potential Balance [#935]
Common mode voltage output is closely associated with switching states in three-phase three-wire neutral-point clamped inverter. Detailed analysis shows avoiding redundant states can effectively improve the common mode voltage, so this paper proposes a pulse width modulation (PWM) technique with zero redundant states to reduce the common mode voltage output, and evaluate their performance with the conventional PWM scheme. This study also takes the issue of neutral point potential compensation into consideration. Laboratory test results are presented to verify the effectiveness of proposed scheme. PM and IPM Motor Drives III Wednesday, September 21, 10:30AM-12:10PM, Room: 101CD, Chair: Takahiro Suzuki, Nicola Bianchi 10:30AM Magnet Temperature Effects on the Useful Properties of Variable Flux PM Synchronous Machines and a Mitigating Method for Magnetization Changes [#690] Brent Gagas, Kensuke Sasaki, Apoorva Athavale, Takashi Kato and Robert Lorenz, University of Wisconsin-Madison, WEMPEC, United States; Nissan Motor Co., Ltd., Japan Variable flux permanent magnet synchronous machines (VF-PMSMs) use permanent magnet magnetization as an additional degree-of-freedom to reduce losses based on operating conditions (e.g., at medium to high speeds, losses are reduced by using a lower magnetization). Magnet properties are known to be dependent on temperature; therefore, the magnet temperature effects on magnetization manipulation and maximum torque properties in VF-PMSMs are investigated in this paper with FEA simulations and experiments. Increased magnet temperature changes the available range of attainable magnetization levels and makes demagnetization occur more easily; therefore, a different current angle and magnetization are needed for maximum torque operation. The temperature effects on high speed magnetization manipulation methods (which are needed for driving cycle loss reduction and full power capability) are evaluated with simulation and experiments on a prototype 80 kW traction machine. A closed loop method for magnetization manipulation that mitigates the effect of temperature is proposed. 10:55AM Nonintrusive Online Rotor Permanent Magnet Temperature Tracking for Permanent Magnet Synchronous Machine Based on Third Harmonic Voltage [#441]
In this paper, a novel nonintrusive online rotor PM temperature tracking method for permanent magnet synchronous machine (PMSM) based on the third harmonic voltage is proposed. The proposed method is not affected by inverter nonlinearities and requires no information of winding resistance, d- and q-axis inductances. It is also robust to the speed variation and introduces no perturbation signals. The third PM flux-linkage is estimated and used as the indicator of the rotor PM temperature. Analytical model for the third harmonic voltage based on the magnetic permeance modulation is proposed to analyze the influence of armature currents. Corresponding third PM flux-linkage amplitude extractor is designed based on this analytical model. Moreover, 2 dimensional finite element analysis is also carried out to verify the effectiveness of the proposed analytical model. Self-commissioning method of the third harmonic flux- linkage tracker is also proposed. Finally, experiments on the 12/slot-10/pole surface mounted permanent magnet synchronous machine verifies the proposed online rotor PM temperature tracking method.
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