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Power Electronics, IEEE Transactions on

Issue 2 • Date Feb. 2010

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Displaying Results 1 - 25 of 35
  • [Front cover]

    Publication Year: 2010 , Page(s): C1
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  • IEEE Transactions on Power Electronics publication information

    Publication Year: 2010 , Page(s): C2
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  • Table of contents

    Publication Year: 2010 , Page(s): 259 - 260
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  • Editorial: Power Electronics Letters

    Publication Year: 2010 , Page(s): 261 - 262
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  • Direct Torque Control of Four-Switch Brushless DC Motor With Non-Sinusoidal Back EMF

    Publication Year: 2010 , Page(s): 263 - 271
    Cited by:  Papers (27)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1065 KB) |  | HTML iconHTML  

    This paper presents a direct torque control (DTC) technique for brushless dc (BLDC) motors with non-sinusoidal back electromotive force (EMF) using a four-switch inverter in the constant torque region. This approach introduces a two-phase conduction mode as opposed to the conventional three-phase DTC drives. Unlike conventional six-step current and voltage control schemes, by properly selecting the inverter voltage space vectors from a simple look-up table at a predefined sampling time, the desired quasi-square wave current is obtained. Therefore, a much faster torque response is achieved compared to conventional current and voltage control schemes. In addition, for effective torque control, a novel switching pattern incorporating the voltage vector look-up table is designed and implemented for a four-switch inverter to produce the desired torque characteristics. Furthermore, to eliminate the low-frequency torque oscillations, pre-stored back EMF constant versus position look-up tables are designed and used in the torque estimation. As a result, it is possible to achieve two-phase conduction DTC of a BLDC motor drive with faster torque response due to the fact that the voltage space vectors are directly controlled. A theoretical concept is developed and the validity and effectiveness of the proposed DTC scheme are verified through the simulations and experimental results. View full abstract»

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  • Single-Phase to Single-Phase Full-Bridge Converter Operating With Reduced AC Power in the DC-Link Capacitor

    Publication Year: 2010 , Page(s): 272 - 279
    Cited by:  Papers (18)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (594 KB) |  | HTML iconHTML  

    This paper presents a control technique based on input and output AC power synchronization to reduce the low frequency AC power and the DC-link voltage fluctuation of a single-phase full-bridge converter. The control technique is based on a technique in which the load voltage is synchronized with the input grid voltage for both constant (Mode I) and variable (Mode II) phase angle. Such approach allows for a reduction in the capacitor size. A capacitor bank design approach is also proposed. The technique has been achieved for the same input and output converter frequency. Simulated and experimental results are addressed. View full abstract»

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  • A Wide-Input–Wide-Output (WIWO) DC–DC Converter

    Publication Year: 2010 , Page(s): 280 - 289
    Cited by:  Papers (15)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1146 KB) |  | HTML iconHTML  

    This paper presents a new wide-input-wide-output dc-dc converter, which is an integration of buck and boost converters via a tapped inductor. Coherent transition between step-down and step-up modes is achieved by a proper control scheme. This paper presents theoretical concepts and experimental results. View full abstract»

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  • Sensorless Control of Surface-Mount Permanent-Magnet Synchronous Motors Based on a Nonlinear Observer

    Publication Year: 2010 , Page(s): 290 - 297
    Cited by:  Papers (48)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3756 KB) |  | HTML iconHTML  

    A nonlinear observer for surface-mount permanent-magnet synchronous motors (SPMSMs) was recently proposed by Ortega et al.(LSS, Gif-sur-Yvette Cedex, France, LSS Internal Rep., Jan. 2009). The nonlinear observer generates the position estimate ???? via the estimates of sin ?? and cos ??. In contrast to Luenberger-type observers, it does not require speed information, thus eliminating the complexity associated with speed estimation errors. Further, it is simple to implement. In this study, the nonlinear observer performance is verified experimentally. To obtain speed estimates from the position information, a proportional-integral (PI) tracking controller speed estimator was utilized. The results are good with and without loads, above 10 r/min. View full abstract»

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  • Use of Hybrid PWM and Passive Resonant Snubber for a Grid-Connected CSI

    Publication Year: 2010 , Page(s): 298 - 309
    Cited by:  Papers (12)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1176 KB) |  | HTML iconHTML  

    Unipolar switching scheme (USS) and bipolar switching scheme (BSS) are popular choices of switching techniques for most inverter applications. Ideally, the output waveform with USS has lower switching loss and harmonic distortion than that with BSS. However, due to the narrow pulses generated around the zero-crossing region, the practical output waveform with USS exhibits pulse-dropping phenomenon that introduces undesirable low-order harmonics. Conversely, BSS does not possess such drawback as the duty cycles of the pulses around the zero-crossing region are close to 0.5. In this paper, a hybrid switching scheme (HSS) that combines the advantages of USS and BSS is proposed and applied to grid-connected current-source inverters. The inverter bridge is predominantly operated in USS and momentarily operated in BSS around the zero-crossing region. A theoretical study shows that the spectral characteristics of HSS are similar to that of an ideal USS. To further reduce the switching loss, the concept of passive resonant snubber is applied to the high-frequency switches in the inverter. The modes of operations, criteria for ensuring soft switching, and design procedures will be addressed in this paper. A 900-W, 220-V, 50-Hz prototype with the HSS and the snubber circuit has been built and tested. A comparative study of the converter efficiencies and total harmonic distortions at the inverter output with different switching schemes will be given. View full abstract»

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  • A Modified SEPIC Converter for High-Power-Factor Rectifier and Universal Input Voltage Applications

    Publication Year: 2010 , Page(s): 310 - 321
    Cited by:  Papers (19)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1325 KB) |  | HTML iconHTML  

    A high-power-factor rectifier suitable for universal line base on a modified version of the single-ended primary inductance converter (SEPIC) is presented in this paper. The voltage multiplier technique is applied to the classical SEPIC circuit, obtaining new operation characteristics as low-switch-voltage operation and high static gain at low line voltage. The new configuration also allows the reduction of the losses associated to the diode reverse recovery current, and soft commutation is obtained with a simple regenerative snubber circuit. The operation analysis, design procedure, and experimental results obtained from a 650-W universal line power-factor-correction prototype of the proposed converter are presented. The theoretical analysis and experimental results obtained with the proposed structure are compared with the classical boost topology. View full abstract»

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  • Analysis of the Dynamic Behavior of a Self-Commutated BTB System During Line Faults

    Publication Year: 2010 , Page(s): 322 - 330
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (448 KB) |  | HTML iconHTML  

    This paper deals with a 50-MW self-commutated back-to-back (BTB) system intended for power-flow control between two ac transmission networks. It focuses on the dynamic behavior of the BTB system during single-line-to-ground and double-line-to-ground faults. Attention is particularly paid to the dc magnetic flux deviation in the grid and converter transformers, and the circulating current inside the grid transformers, which would produce undesirable effects on the system. Theoretical equations related to the amount of circulating current and the dc magnetic flux deviation are derived. The theoretical results developed in this paper are confirmed by computer simulation. View full abstract»

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  • Noncascading Structure for Electronic Ballast Design for Multiple LED Lamps With Independent Brightness Control

    Publication Year: 2010 , Page(s): 331 - 340
    Cited by:  Papers (50)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2753 KB) |  | HTML iconHTML  

    LED light sources, which are more compact, capable to change color in real time, less dissipative, and more durable are finding more applications than conventional light bulbs in domestic, commercial, and industrial environments. However, requirements such as high-power factor, long lifetime, accurate current control, and high-efficiency pose challenges to the design of LED ballast circuits. This paper proposes an LED ballast with a dual noncascading structure. The first-stage noncascading structure is an isolated current-fed power factor correction (PFC) preregulator. In the proposed design, the short-lifetime high-voltage storage capacitor at the primary is replaced by a long-lifetime low-voltage capacitor at the secondary, thus extending the overall system lifetime. The PFC is programmed by the conventional averaged current-mode control for high-power-factor applications. Furthermore, the high-voltage stress on the main switch, which is typical in current-fed converters, is reduced substantially by appropriately exploiting the transformer leakage inductance. The design uses two secondary transformer windings and an LED current driver to form a second noncascading structure to improve efficiency. Multiple noncascading structures can be used for LED lamps for instant independent brightness control. Analysis, design example, and prototype verification are given for the LED ballast. View full abstract»

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  • Model-Based Predictive Direct Power Control of Doubly Fed Induction Generators

    Publication Year: 2010 , Page(s): 341 - 351
    Cited by:  Papers (51)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2477 KB) |  | HTML iconHTML  

    This paper presents a predictive direct power control strategy for doubly fed induction generators (DFIGs). The method predicts the DFIG's stator active and reactive power variations within a fixed sampling period, which is used to directly calculate the required rotor voltage to eliminate the power errors at the end of the following sampling period. Space vector modulation is then used to generate the required switching pulses within the fixed sampling period that results in a constant switching frequency. The impact of sampling delay on the accuracy of the sampled active and reactive powers is analyzed, and detailed compensation methods are proposed to improve the power control accuracy and system stability. Experimental results for a 1.5-kW DFIG system demonstrate the effectiveness and robustness of the proposed control strategy during power steps, and variations of rotating speed and machine parameters. System performance for tracking varying stator power references further illustrates the dynamic performance of the proposed method. View full abstract»

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  • An Input Power Factor Control Strategy for High-Power Current-Source Induction Motor Drive With Active Front-End

    Publication Year: 2010 , Page(s): 352 - 359
    Cited by:  Papers (25)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (975 KB) |  | HTML iconHTML  

    This paper proposes an input power factor control strategy for a current-source drive with active front-end. The proposed strategy is realized without modification of the drive's pulsewidth modulation and speed control schemes through the collaborative use of two methods: a modulation index regulation method and a flux adjustment method. Specifically, the modulation index regulation method functions to directly control the dc-link current and voltage, and it can effectively correct a leading input power factor as long as the space vector modulation is used for the inverter. On the other hand, the flux adjustment method can improve the power factor when the power factor is lagging or when the selective harmonic elimination modulation is used for the inverter at high motor speeds. When implemented together, the two methods will complement each other's functionalities and improve the overall compensation performance. Experimental results are obtained from a 600-hp and an 1100-hp drive system. View full abstract»

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  • A Dual-Input–Dual-Output Z-Source Inverter

    Publication Year: 2010 , Page(s): 360 - 368
    Cited by:  Papers (17)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2091 KB) |  | HTML iconHTML  

    This paper presents a new z-source inverter with two AC outputs and two DC inputs. This inverter is based on the z-source inverter and nine-switch inverter. The presented inverter can control amplitude, frequency, and phase of both AC outputs and also control current of both DC inputs. Input dc voltages are boosted to the required level. Also, both outputs continue their operation, even if one of the input voltages is zero. Performance of the proposed inverter is verified by simulation and experimental results. View full abstract»

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  • A Multiple-Input Digitally Controlled Buck Converter for Envelope Tracking Applications in Radiofrequency Power Amplifiers

    Publication Year: 2010 , Page(s): 369 - 381
    Cited by:  Papers (27)  |  Patents (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3775 KB) |  | HTML iconHTML  

    Wireless communication transmitters have very low efficiencies due to the use of linear radiofrequency power amplifiers. Several techniques have been proposed over the years to improve the efficiency of these systems. One of the most promising is called the envelope tracking technique, which is based on using a fast switching mode power supply to provide a varying voltage to the power amplifier that tracks the envelope of the transmitted signal. The amplifier can, thus, operate continuously near its theoretical maximum efficiency, greatly improving the overall efficiency of the communication system. This paper proposes a multilevel digitally controlled power supply suitable for this application. It is shown to perform very well, achieving very high efficiency, high-output power capability and tracking bandwidths above 50 kHz. This paper also shows that the proposed system is able to produce a 15% overall increase in efficiency in a complete envelope tracking system. View full abstract»

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  • Recurrent Neural Networks Based Impedance Measurement Technique for Power Electronic Systems

    Publication Year: 2010 , Page(s): 382 - 390
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (764 KB) |  | HTML iconHTML  

    When designing and building power systems that contain power electronic switching sources and loads, system integrators must consider the frequency-dependent impedance characteristics at an interface to ensure system stability. Stability criteria have been developed in terms of source and load impedance, and it is often necessary to measure system impedance through experiments. Traditional injection-based impedance measurement techniques require multiple online testing that lead to many disadvantages, including prolonged test time, operating point variations, and impedance values at limited frequency points. The impedance identification method proposed in this paper greatly reduces online testing time by modeling the system with recurrent neural networks with adequate accuracy. The recurrent networks are trained with measured signals from the system with only one stimulus injection per frequency decade. The measurement and identification processes are developed, and the effectiveness of this new technique is demonstrated by simulation and laboratory tests. View full abstract»

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  • A Three-Phase Zero-Voltage and Zero-Current Switching DC–DC Converter for Fuel Cell Applications

    Publication Year: 2010 , Page(s): 391 - 398
    Cited by:  Papers (13)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1188 KB) |  | HTML iconHTML  

    In spite of having many advantages, such as low switch voltage and easy implementation, the voltage-fed dc-dc converter has been suffering from problems associated with large transformer leakage inductance due to high transformer turn ratio when it is applied to low-voltage, high-current step-up application such as fuel cells. This paper proposes a new three-phase voltage-fed dc-dc converter, which is suitable for low-voltage, high-current applications. The transformer turn ratio is reduced to half owing to ??-Y connection. The zero-voltage and zero-current switching (ZVZCS) for all switches are achieved over wide load range without affecting effective duty cycle. A clamp circuit not only clamps the surge voltage but also reduces the circulation current flowing in the high-current side, resulting in significantly reduced conduction losses. The duty cycle loss can also be compensated by operation of the clamp switch. Experimental waveforms from a 1.5 kW prototype are provided. View full abstract»

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  • Transient Operation of a Four-Leg Inverter for Autonomous Applications With Unbalanced Load

    Publication Year: 2010 , Page(s): 399 - 407
    Cited by:  Papers (37)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2788 KB) |  | HTML iconHTML  

    In this paper, the transient operation of a four-leg inverter equipped with an innovative control strategy under unbalanced load conditions is investigated. The inverter is proposed for transformerless hybrid power system applications, in order to provide simultaneous supply of three-phase and single-phase AC loads with balanced voltage and constant frequency. The four-leg inverter is controlled to ensure balanced voltage by means of a control strategy based on the decomposition of the supply three-phase voltage and current into instantaneous positive, negative, and homopolar sequence components using phasor representation. These three sequences are controlled independently in their own reference frames as DC signals. The implementation derived for the controller design is also described. The transient operation performance of the proposed control strategy has been tested in simulations with an average model and experimentally using a laboratory prototype. View full abstract»

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  • Modular Motor/Converter System Topology With Redundancy for High-Speed, High-Power Motor Applications

    Publication Year: 2010 , Page(s): 408 - 416
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1925 KB) |  | HTML iconHTML  

    A novel motor/converter system topology is presented, which is ideal for high-power, high-speed motor applications, especially in the case of utilizing permanent-magnet synchronous AC motors. The proposed system utilizes space-shifted, split-phase, motor stator configuration, with a modular converter topology. The stator winding configuration allows current harmonics from the different phases to cancel out each other, while maximizing the fundamental space vector. Hence, the proposed topology does not require the high-frequency pulsewidth modulation normally needed to reduce the time-domain harmonics found in the phase currents. The switching frequency of the power converters can actually be as low as the fundamental frequency, which significantly reduces the switching losses, associated electromagnetic interference mitigation, and cooling requirements. The modularity of the proposed topology also simplifies overall system design and manufacturability, and provides redundancy and inherent fault tolerance. In this paper, the system topology and control strategy are discussed. Simulation and finite-element analysis results are presented to illustrate the harmonic cancellation and other advantages of the proposed topology. Experimental results also confirm the validity of the proposed system topology. View full abstract»

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  • Multivariable Robust Control for a Red–Green–Blue LED Lighting System

    Publication Year: 2010 , Page(s): 417 - 428
    Cited by:  Papers (11)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3544 KB) |  | HTML iconHTML  

    This paper proposes a novel control structure for a red-green-blue (RGB) LED lighting system, and applies multivariable robust control techniques to regulate the color and luminous intensity outputs. RGB LED is the next-generational illuminant for general lighting or liquid crystal display backlighting. The most important feature for a polychromatic illuminant is color adjustability; however, for lighting applications using RGB LEDs, color is sensitive to temperature variations. Therefore, suitable control techniques are required to stabilize both luminous intensity and chromaticity coordinates. In this paper, a robust control system was proposed for achieving luminous intensity and color consistency for RGB LED lighting in a three-step process. First, a multivariable electrical-thermal model was used to obtain RGB LED luminous intensity, in which a lookup table served as a feedforward compensator for temperature and power variations. Second, robust control algorithms were applied for feedback control design. Finally, the designed robust controllers were implemented to control the luminous and chromatic outputs of the system. From the experimental results, the proposed multivariable robust control was deemed effective in providing steady luminous intensity and color for RGB LED lighting. View full abstract»

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  • Novel STATCOM Controller for Mitigating SSR and Damping Power System Oscillations in a Series Compensated Wind Park

    Publication Year: 2010 , Page(s): 429 - 441
    Cited by:  Papers (56)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3384 KB) |  | HTML iconHTML  

    This paper addresses implementation issues associated with a novel damping control algorithm for a STATCOM in a series compensated wind park for mitigating SSR and damping power system oscillations. The IEEE first benchmark model on SSR is adopted with integrating aggregated self-excited induction generator-based wind turbine to perform the studies. The potential occurrence and mitigation of the SSR caused by induction generator effects as well as torsional interactions, in a series compensated wind park, are investigated. The auxiliary subsynchronous damping control loop for the STATCOM based on a novel design procedure of nonlinear optimization is developed to meet the damping torque in the range of critical torsional frequencies. The intelligent shaft monitor (ISM) scheme with synthesized special indicator signals is developed and examined in the STATCOM control structure. The performances of the controllers are tested in steady-state operation and in response to system contingencies, taking into account the impact of SCRs. Simulation results are presented to demonstrate the capability of the controllers for mitigating the SSR, damping the power system oscillation, and enhancing the transient stability margin in response to different SCRs. View full abstract»

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  • Direct Power Control of Doubly-Fed-Induction-Generator-Based Wind Turbines Under Unbalanced Grid Voltage

    Publication Year: 2010 , Page(s): 442 - 452
    Cited by:  Papers (55)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1898 KB) |  | HTML iconHTML  

    In this paper, the behavior of a doubly fed induction generator (DFIG) is studied under unbalanced grid voltage conditions. It is shown that if no special control efforts are employed, the behavior of the generator is deteriorated, basically due to two reasons: electromagnetic torque oscillations and nonsinusoidal current exchange with the grid. These phenomena are first analyzed theoretically as a function of the stator active and reactive instantaneous power exchange by the stator of the DFIG and the grid-side converter (GSC). This analysis provides the main ideas for generation of the active and reactive power references for the rotor-side converter (RSC) and the GSC, controlled by means of direct power control techniques. Therefore, this paper proposes a new algorithm that generates the RSC power references, without the necessity of a sequence component extraction, in order to eliminate torque oscillations and achieve sinusoidal stator currents exchange. On the contrary, the GSC power references are provided by means of voltage and current sequence extraction. Finally, simulation and experimental results successfully validate the proposed power reference generation methods. View full abstract»

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  • A Single-Phase Z-Source Buck–Boost Matrix Converter

    Publication Year: 2010 , Page(s): 453 - 462
    Cited by:  Papers (15)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (4214 KB) |  | HTML iconHTML  

    This paper proposes a new type of converter called a single-phase Z-source buck-boost matrix converter. The converter can buck and boost with step-changed frequency, and both the frequency and the voltage can be stepped up or stepped down. In addition, the converter employs a safe-commutation strategy to conduct along a continuous current path, which results in the elimination of voltage spikes on switches without the need for a snubber circuit. The operating principles of the proposed single-phase Z-source buck-boost matrix converter are described, and a circuit analysis is provided. To verify the performance of the proposed converter, a laboratory prototype was constructed with a voltage of 40 Vrms/60 Hz and a passive RL load. The simulation and the experimental results verified that the converter can produce an output voltage with three different frequencies 120, 60, and 30 Hz, and that the amplitude of the output voltage can be bucked and boosted. View full abstract»

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  • A Real-Time Thermal Model of a Permanent-Magnet Synchronous Motor

    Publication Year: 2010 , Page(s): 463 - 474
    Cited by:  Papers (29)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3337 KB) |  | HTML iconHTML  

    This paper presents a real-time thermal model with calculated parameters based on the geometry of the different components of a permanent-magnet synchronous motor. The model in state-space format has been discretized and a model-order reduction has been applied to minimize the complexity. The model has been implemented in a DSP and predicts the temperature of the different parts of the motor accurately in all operating conditions, i.e., steady-state, transient, and stall torque. The results have been compared with real measurements using temperature transducers showing very good performance of the proposed thermal model. View full abstract»

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Aims & Scope

IEEE Transactions on Power Electronics covers fundamental technologies used in the control and conversion of electric power.

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