Starting of a free-piston linear engine-generator by mechanical resonance and rectangular current commutation

Zulkifli, Saiful A.; Karsiti, Mohd Noh; Aziz, Abdul

doi:10.1109/vppc.2008.4677748

Cited by 27 publications

(23 citation statements)

References 3 publications

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“…When the FPLG has two cylinders, the piston motion is mainly controlled by LEM during the starting process. Some studies focused on the starting process using position feedback or the constant-magnitude motoring force approach [37,[42][43][44][45]. In order to obtain a desired piston trajectory, the position error serves as a feedback variable to control the thrust force with appropriate value and direction [43].…”

Section: Atarting Methods Of Fplgsmentioning

confidence: 99%

A Review of the Design and Control of Free-Piston Linear Generator

et al. 2018

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The Free-piston linear generator (FPLG) is a novel energy converter which can generate electrical energy and is regarded as a potential technology for solving the restriction of the short driving range of electric vehicles. Getting rid of the crank and flywheel mechanism, FPLG obtains some advantages of a variable compression ratio, compact size, and highly-efficient power generation. Linear electric machine (LEM) design and piston motion control are two key technologies of FPLG. However, they are currently the main obstacles to the favorable performance of FPLG. LEM being used to drive the piston motion or generate electric energy is an integrated design including a motor/generator. Various types of LEMs are investigated, and suitable application scenarios based on advantages and disadvantages are discussed. The FPLG's controller is used to ensure stable operation and highly-efficient output. However, cycle-to-cycle variations of the combustion process and motor/generator switching make it difficult to improve the performance of the piston motion control. Comments on the advantages and disadvantages of different piston motion control methods are also given in this paper.The piston moves freely between TDC and bottom dead center (BDC), and its motion is determined by the resultant force that is acting upon it, including gas pressure force, electro-magnetic force, and rebound force [8][9][10]. The piston motion must be controlled by an electronic control system-an electronic crankshaft, which is an integrated control of combustion parameters or control variables of the LEM and rebound devices [5]. Moreover, there are cycle-to-cycle variations and periodic large disturbances during the combustion process. As a result, piston motion control is still the biggest challenge of FPLG [11]. Besides, LEM is not only used as a power output unit but also a control unit for adjusting the movement of the piston. For the FPLG, LEM requires high reliability, high precision, high efficiency, and so on. Various structures of LEM designed by many teams around the world have been investigated, but none of these meet all of the requirements due to the short stroke, high frequency, and high acceleration.In order to lucubrate the current existing problems, this paper reviews the key technologies of LEM design and FPLG motion control. Firstly, several basic structures of FPLG are introduced, and both their advantages and disadvantages are analyzed. Afterwards, according to the different types of structure, corresponding advantages and disadvantages of LEMs are presented. With respect to the existing LEMs, they are classified according to the different flux path and topology structures in the third section. Finally, different starting methods are introduced based on the FPLG's structure. In terms of power generation stage, piston motion control strategies are divided into three forms and introduced based on their control variables. They include three categories: active combustion parameters control, active LEM control, and the mixed cont...

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Section: Atarting Methods Of Fplgsmentioning

confidence: 99%

A Review of the Design and Control of Free-Piston Linear Generator

et al. 2018

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“…Some research into starting FPLEs examined piston dynamics under various operating parameters such as induced current, and thrust force, as shown in Refs. [58][59][60][61]. Jia et al [61] experimentally investigated the starting process of an FPLE under the effects of thrust force.…”

Section: Piston Dynamicsmentioning

confidence: 99%

A review of free-piston linear engines

2016

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“…Many starting problems arise with the free-piston linear generators. A number of starting methods using an electric motor have been implemented [17,18] and a spring-mass system for starting the engine was proposed in [19]. A two-stroke spark-ignited free-piston linear generator engine prototype was designed and built for research purposes at West Virginia University (WVU).…”

Section: Hydrogen-di Cylinder Headmentioning

confidence: 99%

Effect of Motoring Voltage on Compression Ratio of a Free-Piston Linear Generator Engine

A.¹,

Ibrahim²,

Aziz³

et al. 2015

J. Mech. Eng. Sci.

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The need for alternative power sources is crucial because of the increase in global energy demand and stringent emission regulations. The free-piston linear generator engine is one of the main alternatives thanks to its high efficiency, wide operating range and low emissions. However, low compression pressure which produces low power generation is an obstacle to its development. In order to increase compression pressure, further development of the motoring process is required. The study investigated the effect of motoring voltage in compression pressure and compression ratio. Motoring voltages varied from 36 V to 84 V. Higher motoring voltage increased piston speed up to 2 m/s which reduced the air leakage and thus produced a sharper p-V profile and higher compression pressure. An inverse relationship between the compression ratio and compression pressure during motoring was also observed.

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Starting of a free-piston linear engine-generator by mechanical resonance and rectangular current commutation

Cited by 27 publications

References 3 publications

A Review of the Design and Control of Free-Piston Linear Generator

A Review of the Design and Control of Free-Piston Linear Generator

A review of free-piston linear engines

Effect of Motoring Voltage on Compression Ratio of a Free-Piston Linear Generator Engine

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