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D.W. Novotny

Bio: D.W. Novotny is an academic researcher from University of Wisconsin-Madison. The author has contributed to research in topics: Torque & Induction motor. The author has an hindex of 15, co-authored 17 publications receiving 1504 citations.

Papers
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Journal ArticleDOI
TL;DR: In this article, the authors proposed a new charge equalization technique for a series string of battery cells, which utilizes a simple isolated DC-to-DC power converter with a capacitive output filter along with a multiwinding transformer.
Abstract: Charge equalization for series-connected battery strings has important ramifications on battery life. It enhances the uniformity of the battery cells and, hence, improves the life of the battery as a whole. A new charge equalization technique for a series string of battery cells has been recently proposed by the authors. The basic technique utilizes a simple isolated DC-to-DC power converter with a capacitive output filter along with a multiwinding transformer. The possibility of integrating the trickle charge function with the charge equalization function is potentially very attractive, as it can lead to an efficient and low-cost implementation.

279 citations

Journal ArticleDOI
TL;DR: In this paper, a closed-form analytical technique for analyzing surface PM machines equipped with fractional-slot concentrated windings is presented, which is capable of analyzing the machine both below (constant-torque) and above (flux-weakening) base speed.
Abstract: This paper presents a closed-form analytical technique for analyzing surface PM machines equipped with fractional-slot concentrated windings. Since this class of winding configuration deviates significantly from conventional sinusoidal distributions, classical steady-state phasor or dq analytical techniques cannot be used to provide accurate results. The presented analytical model provides a fast and reliable method to analyze and compare candidate machine designs. Stator slotting effects are taken into consideration and a wide range of concentrated winding configurations can be analyzed. This technique is capable of analyzing the machine both below (constant-torque) and above (flux-weakening) base speed. Average torque, cogging torque, and ripple torque are all evaluated. Analytical results are verified using finite element analysis.

222 citations

Proceedings ArticleDOI
02 Oct 1993
TL;DR: In this article, the rotor and stator flux observers were used to achieve direct field orientation (DFO) of induction machines based on closed-loop, stator, and rotor flux observers.
Abstract: This paper focuses on methods of achieving direct field orientation (DFO) of induction machines based on closed-loop, stator, and rotor flux observers which are well suited to both zero and very high-speed operation. Both observer topologies are dominated by a current model at zero and low speeds, and a voltage model at high speeds. Application of such rotor and stator flux observers to both stator and rotor direct field orientation is presented, including experimental results for three different methods. The influence which flux regulation has on parameter sensitivity of the complete DFO system is analyzed. A rotor-flux-regulated and -oriented system is shown to be sensitive to leakage inductance under high slip (i.e., field weakened) operation. Both a stator-flux-regulated and -oriented system and a stator-flux-regulated, rotor-flux-oriented system are shown to have reduced parameter sensitivity at high speeds. Unlike stator flux orientation using simple voltage integration stator flux models, excellent zero and low-speed operation of an observer-based stator-flux-oriented system is demonstrated. >

216 citations

Proceedings ArticleDOI
05 Mar 1995
TL;DR: In this article, the authors proposed a new charge equalization technique for a series string of battery cells, which utilizes a simple isolated DC-to-DC power converter with a capacitive output filter along with a multi-winding transformer.
Abstract: Charge equalization for series connected battery strings has important ramifications on battery life. It enhances the uniformity of the battery cells and hence improves the life of the battery as a whole. A new charge equalization technique for a series string of battery cells has been recently proposed by the authors. The basic technique utilizes a simple isolated DC-to-DC power converter with a capacitive output filter along with a multi-winding transformer. The possibility of integrating the trickle charge function with the charge equalization function is potentially very attractive, as it can lead to an efficient and low cost implementation. >

204 citations

Journal ArticleDOI
02 Oct 1988
TL;DR: A single-phase induction motor using a novel electronically controlled capacitor using a DC capacitor switched by a transistor H bridge and a continuously variable capacitance in series with the auxiliary winding is described.
Abstract: A single-phase induction motor using an electronically controlled capacitor is described. The system uses a DC capacitor switched by a transistor H bridge. By proper control of the transistor switching, the circuit synthesizes a continuously variable capacitance in series with the auxiliary winding. The system could be used to replace standard single-phase motor capacitor configurations to provide improved machine performance. The basic system is described and compared with a normal capacitor-run motor. The effects of independent adjustments in several system parameters are considered, and the circuit device requirements are described. Both analog and digital simulations are used to carry out the analysis. Illustrations of some of the design flexibility inherent in the system are included. >

109 citations


Cited by
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Journal ArticleDOI
Languang Lu1, Xuebing Han1, Jianqiu Li1, Jianfeng Hua, Minggao Ouyang1 
TL;DR: In this article, a brief introduction to the composition of the battery management system (BMS) and its key issues such as battery cell voltage measurement, battery states estimation, battery uniformity and equalization, battery fault diagnosis and so on, is given.

3,650 citations

Journal ArticleDOI
TL;DR: In this paper, the authors present the current status and implementation of battery chargers, charging power levels, and infrastructure for plug-in electric vehicles and hybrid vehicles and classify them into off-board and on-board types with unidirectional or bidirectional power flow.
Abstract: This paper reviews the current status and implementation of battery chargers, charging power levels, and infrastructure for plug-in electric vehicles and hybrids. Charger systems are categorized into off-board and on-board types with unidirectional or bidirectional power flow. Unidirectional charging limits hardware requirements and simplifies interconnection issues. Bidirectional charging supports battery energy injection back to the grid. Typical on-board chargers restrict power because of weight, space, and cost constraints. They can be integrated with the electric drive to avoid these problems. The availability of charging infrastructure reduces on-board energy storage requirements and costs. On-board charger systems can be conductive or inductive. An off-board charger can be designed for high charging rates and is less constrained by size and weight. Level 1 (convenience), Level 2 (primary), and Level 3 (fast) power levels are discussed. Future aspects such as roadbed charging are presented. Various power level chargers and infrastructure configurations are presented, compared, and evaluated based on amount of power, charging time and location, cost, equipment, and other factors.

2,327 citations

Journal ArticleDOI
TL;DR: This paper will cover the theory and design of FSCW synchronous PM machines, achieving high-power density, flux-weakening capability, comparison of single- versus double-layer windings, fault-tolerance rotor losses, parasitic effects, compared of interior versus surface PM machine, and various types of machines.
Abstract: Fractional-slot concentrated-winding (FSCW) synchronous permanent magnet (PM) machines have been gaining interest over the last few years. This is mainly due to the several advantages that this type of windings provides. These include high-power density, high efficiency, short end turns, high slot fill factor particularly when coupled with segmented stator structures, low cogging torque, flux-weakening capability, and fault tolerance. This paper is going to provide a thorough analysis of FSCW synchronous PM machines in terms of opportunities and challenges. This paper will cover the theory and design of FSCW synchronous PM machines, achieving high-power density, flux-weakening capability, comparison of single- versus double-layer windings, fault-tolerance rotor losses, parasitic effects, comparison of interior versus surface PM machines, and various types of machines. This paper will also provide a summary of the commercial applications that involve FSCW synchronous PM machines.

1,126 citations

Journal ArticleDOI
TL;DR: In this article, the performance of the two control schemes is evaluated in terms of torque and current ripple, and transient response to step variations of the torque command, where secondary effects introduced by hardware implementation are not present.
Abstract: Field-oriented control and direct torque control are becoming the industrial standards for induction motors torque control. This paper is aimed at giving a contribution for a detailed comparison between the two control techniques, emphasizing advantages and disadvantages. The performance of the two control schemes is evaluated in terms of torque and current ripple, and transient response to step variations of the torque command. The analysis has been carried out on the basis of the results obtained by numerical simulations, where secondary effects introduced by hardware implementation are not present.

1,030 citations

Journal ArticleDOI
TL;DR: This paper reviews state-of-the-art ESSs in automotive applications and hybrid power sources are considered as a method of combining two or more energy storage devices to create a superior power source.
Abstract: The fuel efficiency and performance of novel vehicles with electric propulsion capability are largely limited by the performance of the energy storage system (ESS). This paper reviews state-of-the-art ESSs in automotive applications. Battery technology options are considered in detail, with emphasis on methods of battery monitoring, managing, protecting, and balancing. Furthermore, other ESS candidates such as ultracapacitors, flywheels and fuel cells are also discussed. Finally, hybrid power sources are considered as a method of combining two or more energy storage devices to create a superior power source.

982 citations