Online ISSN
1751-8679
Print ISSN
1751-8660
IET Electric Power Applications
Volume 1, Issue 2, March 2007
Volumes & issues:
Volume 1, Issue 2
March 2007
-
- Author(s): W.Y. Choi ; J.M. Kwon ; B.H. Kwon
- Source: IET Electric Power Applications, Volume 1, Issue 2, p. 133 –142
- DOI: 10.1049/iet-epa:20060222
- Type: Article
- + Show details - Hide details
-
p.
133
–142
(10)
A highly efficient light-emitting-diode back-light power supply is proposed for liquid-crystal display. The proposed power supply consists of a bridgeless boost rectifier for power-factor correction and the asymmetrical half-bridge flyback converter with synchronous rectifier (SR) for DC-DC power conversion. In the proposed bridgeless boost rectifier, the diode reverse-recovery losses are reduced by achieving zero-current turn-off of the output diodes, as well as zero-current turn-on of the additional diodes. The reverse-recovery transients of the diodes are improved by a simple passive snubber circuit. For a DC-DC converter, the asymmetrical half-bridge flyback converter operates under zero-voltage switching for the power switches, and the SR switch operates under zero-current switching. The analysis of the proposed converter is presented and its design considerations are discussed in detail. Experimental results based on 28 V, 300 W back-light power are provided to demonstrate the performance of the proposed converter. - Author(s): J.B. Wang and C.Y. Chuang
- Source: IET Electric Power Applications, Volume 1, Issue 2, p. 143 –152
- DOI: 10.1049/iet-epa:20045145
- Type: Article
- + Show details - Hide details
-
p.
143
–152
(10)
A microprocessor-controlled multiphase battery charger, to enhance current utilisation of the power supply unit (PSU) and also avoid overvoltage problems during regenerative periods, is presented. The charger consists of a PSU and three sets of independent current-controlled buck-derived converters that adopt time-shifted pulse-charging current commands. Owing to the multiphase pulse-charging current control scheme, the output-current utilisation of the PSU can be improved remarkably. Moreover, the negative pulse-discharging current is recycled back to the next phase positive pulse-charging current, and thus compensates for the overvoltage of the PSU during this period. According to output voltage specification of the PSU, maximum output-power limitation, duty ratio and current ripples of the output inductor, the desired output voltage and maximum amplitude of the pulse-charging current command can be determined for the small capacity sealed lead-acid battery. The design procedures of the multiphase battery charger are given. Finally, some simulation and experimental results to show the overvoltage problem of the PSU, during negative discharging period, can be improved significantly by the proposed multiphase battery charging scheme. - Author(s): H.W. de Kock and M.J. Kamper
- Source: IET Electric Power Applications, Volume 1, Issue 2, p. 153 –160
- DOI: 10.1049/iet-epa:20060325
- Type: Article
- + Show details - Hide details
-
p.
153
–160
(8)
A digital signal processor-based control system for the permanent magnet-assisted reluctance synchronous machine, with the emphasis on dynamic performance, is proposed. A classical design approach is used to design the current and speed controllers for the machine. The stator current of the machine is controlled in such a way that the current angle in the dq synchronous reference frame is constant. The load–torque is estimated using a state space observer and compensation current based on the estimated load is used to improve the dynamic performance of the drive. The control system design is machine specific as it relies on data from finite-element analysis. Simulated and measured results on a 110-kW power level show that the resulting control system is stable and robust with good dynamic performance. - Author(s): S.K. Chen ; T.K. Ho ; B.H. Mao
- Source: IET Electric Power Applications, Volume 1, Issue 2, p. 161 –172
- DOI: 10.1049/iet-epa:20060244
- Type: Article
- + Show details - Hide details
-
p.
161
–172
(12)
High reliability of railway power systems is one of the essential criteria to ensure quality and cost-effectiveness of railway services. Evaluation of reliability at system level is essential for not only scheduling maintenance activities, but also identifying reliability-critical components. Various methods to compute reliability on individual components or regularly structured systems have been developed and proven to be effective. However, they are not adequate for evaluating complicated systems with numerous interconnected components, such as railway power systems, and locating the reliability critical components. Fault tree analysis (FTA) integrates the reliability of individual components into the overall system reliability through quantitative evaluation and identifies the critical components by minimum cut sets and sensitivity analysis. The paper presents the reliability evaluation of railway power systems by FTA and investigates the impact of maintenance activities on overall reliability. The applicability of the proposed methods is illustrated by case studies in AC railways. - Author(s): B.R. Lin and C.L. Huang
- Source: IET Electric Power Applications, Volume 1, Issue 2, p. 173 –182
- DOI: 10.1049/iet-epa:20060157
- Type: Article
- + Show details - Hide details
-
p.
173
–182
(10)
The paper presents an active clamp buck-boost stage Cuk converter to achieve soft switching commutation. An auxiliary switch and a clamp capacitor are connected in parallel with the primary side of the transformer to absorb all the energy stored in the transformer leakage inductance. The resonant inductance and the clamp capacitance are resonant to achieve zero-voltage switching (ZVS) of the auxiliary switch. On the other hand, the resonance between the resonant inductance and output capacitance of the main switch will achieve ZVS of the main switch in the proposed converter. The principle of operation and system analysis are presented. Design considerations of the proposed converter are also provided. Experimental results for a 170 W prototype circuit operating at 70 kHz are given to demonstrate the effectiveness of the proposed converter. - Author(s): B. Roodenburg ; A. Taffone ; E. Gilardi ; S.M. Tenconi ; B.H. Evenblij ; M.A.M. Kaanders
- Source: IET Electric Power Applications, Volume 1, Issue 2, p. 183 –192
- DOI: 10.1049/iet-epa:20060295
- Type: Article
- + Show details - Hide details
-
p.
183
–192
(10)
Power electronic switches have been considered for load switching ever since their invention. This is because semiconductor switches enable fast, arc-less, reliable and maintenance-free switching. The main disadvantages in relation to conventional switches (i.e. circuit breakers), however, are their sensitivity to transients, high on-state losses and the presence of leakage current. The advantages of both types of switches can be exploited by combining the semiconductor and the mechanical switch and thereby their disadvantages, arc formation and regular maintenance, can also be eliminated. For hybrid switches (HSs), both zero voltage switching (ZVS) and zero current switching (ZCS) are frequently used. A new hybrid switching topology has been developed where both ZVS and ZCS techniques are applied to the mechanical switch. The ‘symbiosis’ between these solid-state switching techniques and a mechanical switch eliminates several of the disadvantages, resulting in a more reliable direct current (DC) HS that requires less maintenance. The first turn-off measurement (up to 5 kA) from a prototype that has been developed for a 3-kV DC grid is presented. - Author(s): C.L. Pires ; S.I. Nabeta ; J.R. Cardoso
- Source: IET Electric Power Applications, Volume 1, Issue 2, p. 193 –198
- DOI: 10.1049/iet-epa:20060174
- Type: Article
- + Show details - Hide details
-
p.
193
–198
(6)
In a railway line, trains are constantly changing their positions and loads. At each specific time, trains, substations, contact line and earthing system establish a different DC circuit configuration. To solve those circuits, several approaches were tested. These approaches may be divided into linear systems and nonlinear systems. The ICCG (incomplete cholesky conjugate gradient) solver for DC traction load flow is proposed in the paper. This method is described and applied to a test circuit. To verify the ICCG effectiveness applied to DC traction load flow, a comparison with other commonly used methods is made. - Author(s): N. Bel Hadj-Youssef ; K. Al-Haddad ; H.Y. Kanaan ; F. Fnaiech
- Source: IET Electric Power Applications, Volume 1, Issue 2, p. 199 –208
- DOI: 10.1049/iet-epa:20060200
- Type: Article
- + Show details - Hide details
-
p.
199
–208
(10)
New small-signal-modelling technique and validation procedures are applied to a three-phase three-level boost-type AC/DC Vienna converter. The adopted methodology consists of three steps: the first one is to elaborate the converter steady state and dynamic models that are derived by means of a local linearisation around the nominal operating point from the state space-averaged model, initially expressed in abc physical variables and then transformed into dqo synchronous reference frame. Twenty transfer functions relating the inputs to the outputs of the system are therefore obtained. The second step is the numerical verification using the averaged state space model and the converter model built in SIMULINK/MATLAB. Finally, an experimental validation of the transfer functions is carried out using a 1.5 kW laboratory prototype on the basis of the DS 1104 real-time controller board of dSPACE. The results are quantified and compared as magnitude and phase Bode graphs. It is confirmed that the proposed new small-signal model represents rather accurately the real system and is therefore reliable for further tasks such as dynamic characteristic analysis, numerical simulation as well as controller design purposes. - Author(s): P. Božović and P. Pejović
- Source: IET Electric Power Applications, Volume 1, Issue 2, p. 209 –216
- DOI: 10.1049/iet-epa:20060130
- Type: Article
- + Show details - Hide details
-
p.
209
–216
(8)
A three-phase rectifier that applies current injection to reduce the input current total harmonic distortion (THD) is proposed. The rectifier injects rectangular current, which results in the waveforms of the input currents the same as in the case of 12-pulse rectifiers, with the THD equal to 15.22%. The current injection system applies a voltage-loaded resistance emulator. To simplify the rectifier analysis, an equivalent circuit of the rectifier is derived, which significantly reduces the number of nonlinear elements. Analytical optimisation of the resistance emulator transformer turns ratio is performed for the case when the losses in the current injection system can be neglected. Influence of the losses in the current injection system is analysed numerically, and it is shown that they considerably affect the rectifier performance and design. Numerical optimisation of the resistance emulator turns ratio in the presence of losses is performed. Analytical results are experimentally verified on a rectifier with a rated power of 3 kW. - Author(s): A.M. El-Refaie and T.M. Jahns
- Source: IET Electric Power Applications, Volume 1, Issue 2, p. 217 –222
- DOI: 10.1049/iet-epa:20060249
- Type: Article
- + Show details - Hide details
-
p.
217
–222
(6)
A thorough comparison of the converter performance characteristics for four permanent magnet (PM) synchronous machine configurations is presented. Two versions of an interior PM (IPM) machine with distributed windings are included. One version has a maximum back-EMF limit at the top speed while the second does not have any constraint on back-EMF amplitude. Two types of surface PM (SPM) machines are also considered, one with fractional-slot concentrated windings, and another with conventional distributed windings. The target application is an automotive direct-drive starter/alternator requiring a very wide 10∶1 constant power speed ratio (CPSR). Detailed comparisons of the converter performance below and above the base speed are presented, evaluating significant issues, including the converter switching and conduction losses, output ripple current, and DC-link current ripple. Study results show that the higher excitation frequencies required by PM machines with high pole numbers have only a modest impact on converter efficiency for comparable output current waveform quality. In constrast, the imposition of maximum back-EMF amplitude constraints at top speed raise the machine rated current, resulting in elevated converter losses and larger DC-link capacitors. - Author(s): R.C. Okonkwo and R. Hanitsch
- Source: IET Electric Power Applications, Volume 1, Issue 2, p. 223 –228
- DOI: 10.1049/iet-epa:20060119
- Type: Article
- + Show details - Hide details
-
p.
223
–228
(6)
Most advanced manufacturing processes require precise linear-position control for material transfer, packaging and assembly. To achieve precise linear motion, most of these high-performance manufacturing machines use rotary motors and rotary-to-linear couplers. Although this method is widely used, it has the disadvantages of low accuracy, complex mechanical adjustments, high cost and low reliability. A prototype permanent-magnet DC linear motor that is used as a direct-linear drive for position-control applications is described. Experimental investigation of the motion system indicates that the constructed prototype has response with good accuracy. - Author(s): Y.-K. Lo ; J.-M. Wang ; H.-J. Chiu ; C.-H. Chang
- Source: IET Electric Power Applications, Volume 1, Issue 2, p. 229 –238
- DOI: 10.1049/iet-epa:20060158
- Type: Article
- + Show details - Hide details
-
p.
229
–238
(10)
High-performance voltage-regulator modules for the new generation of microprocessors have many strict and challenging specifications, such as high power density, high output-current capability, low output-voltage deviation and fast transient response. A dual mode control multiphase DC/DC converter is presented, which combines voltage and hysteretic control modes and has the merits of high efficiency, simple control and fast transient response. It can also be used for single-phase and built-in integrated circuits without requiring additional cost and space. The operating principles and design considerations are analysed and discussed in detail. A 1.3 V/80 A four-phase laboratory prototype is simulated and implemented to verify the feasibility of the proposed scheme. The results prove to be satisfactory. - Author(s): T. Ahmed ; K. Nishida ; M. Nakaoka
- Source: IET Electric Power Applications, Volume 1, Issue 2, p. 239 –247
- DOI: 10.1049/iet-epa:20050535
- Type: Article
- + Show details - Hide details
-
p.
239
–247
(9)
The paper describes a simple control structure for a vector-controlled stand-alone induction generator (IG) used to operate under variable speeds. Deadbeat current control is developed for a voltage source PWM converter and the three-phase variable speed squirrel-cage IG to regulate DC-link and generator voltages with newly designed phase-locked-loop circuit. The required reactive power for the variable-speed IG is supplied by means of the PWM converter and a capacitor bank to build up the voltage of the IG without the need for a battery and to reduce the rating of the PWM converter with the need for only three sensors. This proposed scheme can be used efficiently for variable speed wind or hydro energy conversion systems. The measurements of the IG system at various speeds and loads are given and show that this proposed system is capable of good AC and DC voltages regulation. - Author(s): Y.-J. Kim and H. Dohmeki
- Source: IET Electric Power Applications, Volume 1, Issue 2, p. 248 –254
- DOI: 10.1049/iet-epa:20060266
- Type: Article
- + Show details - Hide details
-
p.
248
–254
(7)
Permanent-magnet linear synchronous motors (PMLSM) have been used as the driving source of transportation systems to satisfy requirements such as the speeding up of transportation systems and to simplify maintenance. The authors' laboratory has proposed a stationary discontinuous-armature PMLSM in which the armature is engaged only when accelerated and decelerated operation is necessary, to resolve the problem of higher costs when PMLSM is used with long-distance transportation systems in factories. A constant-torque angle control without position feedback has been proposed to suppress the velocity ripple that occurs at the re-acceleration portion' with the aim of maintaining smooth drive of the stationary discontinuous armature PMLSM. As a result of the examination of the re-acceleration characteristics a stable re-acceleration of the control is possible without position feedback is confirmed. To achieve stable-deceleration driving the velocity ripple that occurred using constant-torque angle control without position feedback during deceleration was examined. This paper describes the results obtained using constant-torque angle control without position feedback, proposed as an innovative driving method to suppress the velocity ripple which occurs in the deceleration portion, with the aim of maintaining smooth drive of the stationary discontinuous armature PMLSM. The characteristics of closed-loop control and the proposed deceleration method were compared to confirm the effectiveness of the proposed deceleration method. - Author(s): J. Luukko and J. Pyrhönen
- Source: IET Electric Power Applications, Volume 1, Issue 2, p. 255 –263
- DOI: 10.1049/iet-epa:20060298
- Type: Article
- + Show details - Hide details
-
p.
255
–263
(9)
The selection of the parameters of a permanent magnet synchronous machine (PMSM) is analysed using nonlinear optimisation. The constraints of the optimisation can be set to take the control principle into account. Compared with previously presented analyses, constant flux-based control as well as an absolute maximum criterion where no constraints are made to the control principle is analysed. Moreover, the requirements of the application are easily incorporated into the presented optimisation as additional constraints. On the basis of the results, the parameters of the PMSM (permanent magnet's flux linkage and the direct and quadrature axis inductances) can be selected. The results show that when using a constant flux linkage-based control principle (e.g. direct-torque control) more torque can be obtained compared with minimum current vector control. After analysing the effect of different parameters, a design procedure is suggested and an interactive design programme is implemented with Matlab. - Author(s): G.H. Tan ; J.Z. Wang ; Y.C. Ji
- Source: IET Electric Power Applications, Volume 1, Issue 2, p. 264 –274
- DOI: 10.1049/iet-epa:20060236
- Type: Article
- + Show details - Hide details
-
p.
264
–274
(11)
A novel single-phase flyback inverter for photovoltaic applications is proposed to achieve low-frequency ripple current reduction on the DC busbar and to draw sinusoidal current into the AC grid. Based on capacitive idling techniques, the proposed circuit topology is derived from a single-ended primary-inductance converter and two-switch flyback inverter to obtain soft-switching operation for all of the active switches. Compared with a buck-boost inverter and other flyback inverter topologies for AC photovoltaic module systems, no extra active switches are used in the proposed inverter to realise both soft-switching and enhanced power decoupling with only four active switches. Peak-current mode control method is employed in the control schemes to ensure pure sinusoidal current with unity power factor on the AC grid. Laboratory experimental results based on a 500 W prototype are provided to verify the effectiveness of the proposed inverter. - Author(s): R.J. Wai ; C.Y. Lin ; Y.R. Chang
- Source: IET Electric Power Applications, Volume 1, Issue 2, p. 275 –283
- DOI: 10.1049/iet-epa:20050514
- Type: Article
- + Show details - Hide details
-
p.
275
–283
(9)
The paper focuses on the development of a novel maximum-power-extraction algorithm (MPEA) including a maximum-power error-driven (MPED) mechanism and a maximum-power differential-speed (MPDS) control, for a wind generation system with a permanent-magnet synchronous generator (PMSG). In the proposed MPEA scheme, the MPED mechanism, operating like a traditional hill-climbing method, drives the output power gradually increasing to its maximum value by regulating the direction of current command according to the power variation trend. The MPDS control produces an additional step of current command based on the instantaneous difference of generator speeds, so that it can prevent the wind turbine from stalling at the suddenly dropping wind speed and achieve the object of maximum power extraction instantly as a stiff wind flowing through the wind turbine. In addition, the output is connected to a utility grid for providing energy flexibility via a unipolar full-bridge inverter controlled by a digital signal processor. The grid-connected experimentations of the proposed MPEA scheme, without any mechanical sensors for a wind-power emulation system via a PMSG driven by an induction motor, are given to examine its feasibility in practical applications. - Author(s): W. Li and X. He
- Source: IET Electric Power Applications, Volume 1, Issue 2, p. 284 –290
- DOI: 10.1049/iet-epa:20060239
- Type: Article
- + Show details - Hide details
-
p.
284
–290
(7)
The narrow turn-off period of the conventional boost converters limits their applications in high step-up DC–DC conversion. The voltage gain is extended without an extreme duty-cycle by the winding-coupled inductor structure. However, the leakage inductance induces large voltage spikes when the switch turns off. An active-clamp circuit is introduced here to clamp the switch turn-off voltage spikes effectively and to recycle the leakage energy. Both the main switches and the auxiliary switches are ZVT during the whole switching transition. Meanwhile, the output diode reverse-recovery problem is alleviated because the leakage inductance of the coupled inductors is in series with the output diode. Furthermore, a family of ZVT interleaved boost converters for high efficiency and high step-up DC–DC conversion is deduced. The experimental results based on 40–380 V front-end applications verify the significant improvements in efficiency.
Efficient LED back-light power supply for liquid-crystal-display
Design considerations of microprocessor-controlled multiphase battery charger with fast-charging strategy
Dynamic control of the permanent magnet-assisted reluctance synchronous machine
Reliability evaluations of railway power supplies by fault-tree analysis
Zero voltage switching active clamp buck-boost stage Cuk converter
Combined ZVS–ZCS topology for high-current direct current hybrid switches: design aspects and first measurements
ICCG method applied to solve DC traction load flow including earthing models
Small-signal perturbation technique used for DSP-based identification of a three-phase three-level boost-type Vienna rectifier
Current-injection-based 12-pulse rectifier using a single three-phase diode bridge
Comparison of synchronous PM machine types for wide constant-power speed operation: converter performance
Development and control of a prototype permanent-magnet DC linear motor
Dual-mode-control multiphase DC/DC converter
Advanced control for PWM converter and variable-speed induction generator
Driving method of stationary discontinuous-armature PMLSM by open-loop control for stable-deceleration driving
Selection of the parameters of a permanent magnet synchronous machine by using nonlinear optimisation
Soft-switching flyback inverter with enhanced power decoupling for photovoltaic applications
Novel maximum-power-extraction algorithm for PMSG wind generation system
ZVT interleaved boost converters for high-efficiency, high step-up DC–DC conversion
Most viewed content for this Journal
Article
content/journals/iet-epa
Journal
5
Most cited content for this Journal
-
PMSG-based wind energy conversion systems: survey on power converters and controls
- Author(s): Venkata Yaramasu ; Apparao Dekka ; Mario J. Durán ; Samir Kouro ; Bin Wu
- Type: Article
-
Model predictive torque control of induction motor drives with reduced torque ripple
- Author(s): Yongchang Zhang ; Haitao Yang ; Bo Xia
- Type: Article
-
Control design and experimental verification of the brushless doubly-fed machine for stand-alone power generation applications
- Author(s): Yi Liu ; Wu Ai ; Bing Chen ; Ke Chen ; Guang Luo
- Type: Article
-
Integrated motor drives: state of the art and future trends
- Author(s): Robert Abebe ; Gaurang Vakil ; Giovanni Lo Calzo ; Thomas Cox ; Simon Lambert ; Mark Johnson ; Chris Gerada ; Barrie Mecrow
- Type: Article
-
Overview of fast on-board integrated battery chargers for electric vehicles based on multiphase machines and power electronics
- Author(s): Ivan Subotic ; Nandor Bodo ; E. Levi ; Boris Dumnic ; Dragan Milicevic ; Vladimir Katic
- Type: Article
