By Topic

Electric Power Applications, IEE Proceedings -

Issue 2 • Date Mar 2001

Filter Results

Displaying Results 1 - 18 of 18
  • Phase-shift controlled DC-DC convertor with bi-directional power flow

    Publication Year: 2001 , Page(s): 193 - 201
    Cited by:  Papers (14)  |  Patents (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (608 KB)  

    A new zero-voltage switching (ZVS) phase-shift controlled bi-directional DC-DC convertor is proposed. It possesses the conventional features of phase-shifted convertors: constant switching frequency, ZVS and voltage regulation by phase-shift control. However, the convertor has been improved by developing a bi-directional power flow capability and applying synchronous rectification: hence, the on-state voltage drop of the active devices is small. It is therefore recommended for use in electric vehicles. The principle of circuit operation of the proposed convertor is described in detail with mathematical analysis, and experimental results are presented to verify the concept View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Digital method for power frequency measurement using synchronous sampling [comment and reply]

    Publication Year: 2001 , Page(s): 225 - 227
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (244 KB)  

    The authors comment on the paper by P. Petrovic et al. (see ibid., vol.146, no.4, p.383-90, 1999). They discuss the mathematical issues of the paper which proposes the application of synchronous undersampling in the measurement of power and RMS values of voltages and currents in an electric power system. The original authors reply to the comments View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Reply

    Publication Year: 2001 , Page(s): 226 - 227
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (156 KB)  

    First Page of the Article
    View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Application of local memory-based techniques for power transformer thermal overload protection

    Publication Year: 2001 , Page(s): 163 - 170
    Cited by:  Papers (5)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (644 KB)  

    Power transformers are some of the most expensive components of electrical power plant. The failure of a transformer is a matter of significant concern for electrical utilities. Not only for the consequent severe economic losses but also because the utility response to a customer during the outage condition is one of the major factors in determining the overall customer attitude towards the utility. Therefore, it is essential to predict the thermal behaviour of a transformer during load cycling and in particular in the presence of overload conditions. The authors propose a novel technique to predict the winding hottest spot temperature of a power transformer in the presence of overload conditions, as an alternative methodology to the radial basis function network (RBFN) based technique presented in a previous paper. The method proposed is based on a modified local memory-based algorithm which. Working on the load current, the top oil temperature rise over ambient temperature and taking into account other meteorological parameters, permits the recognition of the hot spot temperature pattern. In particular some corrective actions for the classical local methods are evidenced to customise it for real-time applications. Data obtained from experimental tests allow the local learning algorithm to be tested to evaluate the performance of the proposed method in terms of accuracy View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Autonomous reluctance generator

    Publication Year: 2001 , Page(s): 105 - 110
    Cited by:  Papers (5)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (452 KB)  

    A single-phase autonomous reluctance generator is analysed as an oscillator with time varying parameters. It is shown that the reluctance generator can be modelled by the parametric Hills equation. The necessary condition for generating AC output power is obtained by using different methods of analysis. Furthermore, when the inductance varies as a square wave, using a piecewise method solves the RG differential equation in an exact manner. In this case, the RG could be driven at a different rotor velocity to elicit the same resonant current and voltage frequency. The analysis is verified by experimental and simulation results View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Evaluations of voltage-source soft-switching inverter with single auxiliary resonant snubber

    Publication Year: 2001 , Page(s): 207 - 213
    Cited by:  Papers (5)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (452 KB)  

    A novel prototype of auxiliary resonant DC link (ARDCL) snubber is proposed. The paper also describes a three-phase space voltage vector modulated sinewave soft-switching inverter using the proposed ARDCL snubber circuit, which together with new voltage vector correction principle can produce high-performance output voltage waveforms. The output voltage waveforms obtained by the software processing of the inverter are able to achieve a high quality sinewave on the basis of the new correction principle. The effectiveness of the resonant DC link three-phase voltage source soft-switching inverter is proven from a practical point of view View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Single-stage electronic ballast with unity power factor

    Publication Year: 2001 , Page(s): 171 - 176
    Cited by:  Papers (4)  |  Patents (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (448 KB)  

    A single-stage electronic ballast with unity power factor is proposed. A saturable transformer constituting the self-oscillating drive limits the lamp current and dominates the switching frequency of the ballast. The proposed ballast has high energy efficiency: low cost and high reliability compared to conventional high-power-factor (HPF) electronic ballasts. Experimental results obtained on two 40 W fluorescent lamps are discussed View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Single-stage high-power-factor dimmable electronic ballast with asymmetrical pulse-width-modulation for fluorescent lamps

    Publication Year: 2001 , Page(s): 125 - 132
    Cited by:  Papers (11)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (664 KB)  

    A single-stage high-power-factor electronic ballast is designed to drive the fluorescent lamp in a wide dimmable range. The electronic ballast with an embedded buck-boost converter can effectively regulate the lamp power by asymmetrical pulse-width-modulation. With carefully designed circuit parameters, the proposed electronic ballast can achieve a high power factor by operating the buck-boost converter at discontinuous conduction mode operation, and high efficiency by controlling the active switches operated at either zero-voltage switching or zero-current switching over the whole dimming range. Design equations are derived and computer analyses are performed based on fundamental approximation and a power-dependent lamp model. A prototype circuit for a T8-36 W fluorescent lamp is built and tested to verify the analytical predictions View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Single-phase three-level regular-sampled selective harmonic elimination PWM

    Publication Year: 2001 , Page(s): 155 - 161
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (576 KB)  

    A new harmonic elimination PWM strategy for single-phase VSI and CSI inverters is presented which closely approximates the exact switching angles produced offline for the harmonic elimination PWM (HEPWM) strategy. The new strategy is developed using well known regular-sampled techniques which enable the calculation of the switching angles in real-time, allowing a simple and efficient digital signal processor implementation. Experimental and computed results are presented in terms of total harmonic distortion and harmonic performance to highlight the advantages of the strategy and to confirm the theoretical developments View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • High-power-factor single-phase capacitor clamped rectifier

    Publication Year: 2001 , Page(s): 214 - 224
    Cited by:  Papers (5)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (828 KB)  

    A control scheme for a single-phase capacitor clamped rectifier is proposed. Flying capacitor configuration has been employed as a power factor correction to achieve a high-input power factor and low-current harmonics. The adopted rectifier allows higher voltage than the voltage stress of the power switches to be achieved. The control scheme, based on a look-up table with hysteresis current controller (HCC), can (i) draw a nearly sinusoidal line current, (ii) achieve a unity power factor, (iii) reduce the current harmonics, and (iv) improve the unbalance problem between capacitor voltages. The applications of the adopted converter can be also used in multilevel active power filters, uninterruptible power supplies and high-power motor drives. The experimental results are shown to confirm the validity of the proposed concept View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Novel technique for power factor correction in flyback converters

    Publication Year: 2001 , Page(s): 177 - 186
    Cited by:  Papers (8)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (636 KB)  

    Due to the necessity of DC power supplies that combine variable step-up and step-down DC output voltage, high power density and low harmonic distortion at the mains side, power factor correction in flyback converters has become a big issue. The paper presents a novel method to achieve high power factor correction in flyback converters without sensing the input current. This method is extended to give to a simplified and accurate design strategy for this type of converter, revealing an optimal solution under any operating point View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Novel fast-acting predictive current mode controller for power electronic converters

    Publication Year: 2001 , Page(s): 133 - 139
    Cited by:  Papers (9)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (640 KB)  

    A proposed general-purpose fast-acting controller with predictive current mode control suitable for power electronic converters is described. The predictive controller regulates the converter output voltage or current with respect to a demand signal, and implements true average current mode control. A four-quadrant single-phase DC/AC converter supplying a variety of loads, including live loads and high crest factor loads, with high di/dt, is used to demonstrate the performance of the controller. Simulation and practical results are presented for this converter View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Analysis of low frequency harmonics for continuous-conduction-mode boost power-factor correction

    Publication Year: 2001 , Page(s): 202 - 206
    Cited by:  Papers (2)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (340 KB)  

    The input current harmonics of continuous-conduction-mode boost power-factor correction (CCMPFC) are presented. Input current distortion of single-phase CCMPFC is analysed and harmonic components are mathematically derived. Upper limits of the boost inductance for CCMPFC are also discussed. Design examples of CCMPFC are demonstrated. Experimental recordings verify the analytical derivations View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Low-harmonic resonant CLL-type AC/DC converter

    Publication Year: 2001 , Page(s): 187 - 192
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (564 KB)  

    A new resonant AC/DC converter is presented. It has been shown that the series parallel CLL topology is particularly useful in resonant rectifier applications. The transformer may be designed to replace one or both the inductances used in the resonant network. The converter is operated only in the lagging power factor mode. Dispensing with the need of an external device snubber. Such a converter is analysed and simulation results are obtained by using MATLAB. Two new control strategies are proposed. Both control schemes are implemented and compared. Scheme 1 requires reduced hardware and no current sensor, but scheme 2 uses a current sensor and an additional PI controller. Scheme 2 performs better than scheme 1 in terms of total harmonic distortion (THD) of the converter input current. A laboratory prototype has been fabricated and excellent performances have been confirmed View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Parallel operation of series-connected PWM voltage regulators without control interconnection

    Publication Year: 2001 , Page(s): 141 - 147
    Cited by:  Papers (6)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (596 KB)  

    A novel current-sharing control scheme is presented that can parallel operate multiple series-connected pulse-width modulation (PWM) voltage regulators (VRs) directly with no control interconnection. The current-sharing control is dedicated for both fundamental and harmonic components. The fundamental current-sharing is controlled by the Q-V droop and P-δ shift scheme, while the harmonic current sharing is controlled by the resistive droop scheme. Both schemes have the feature of no real impedance connection between the VR and the load. Instead, the required impedance for executing both schemes is simulated in the control circuits. As a result, the VRs are tightly connected and thus have a lower output impedance. Other features include accurate voltage regulation, low voltage distortion and tolerance for parameter mismatch. Two 1 kV prototype capacitor current-controlled single-phase VRs with three-arms rectifier-inverter topology are designed and implemented. The effectiveness is demonstrated by some experimental results View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Effects of grounding schemes on rail potential and stray currents in Taipei Rail Transit Systems

    Publication Year: 2001 , Page(s): 148 - 154
    Cited by:  Papers (12)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (488 KB)  

    The effects of different grounding schemes, including ungrounded, solidly grounded, and diode-grounded, on rail potential and stray currents in Taipei Rail Transit Systems are presented. The running rails are used as the return conductor for traction currents, the advantage being that no dedicated return conductor is required while the disadvantages are rail potential and stray current problems. Thus, the analysis of grounding schemes is important and necessary. Sample simulation results for the Tamshui line between Chuwei and Kuantu stations are presented View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Development of a linear brushless DC motor drive with robust position control

    Publication Year: 2001 , Page(s): 111 - 118
    Cited by:  Papers (14)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (576 KB)  

    The design and implementation of a linear brushless DC motor (LBDCM) drive with robust position control are presented. Hall-effect sensors and linear encoders are employed to obtain information of moving member position. A simple but practical zeroing approach is proposed to correct the phase errors of current commands due to the mechanical installation misalignment of Hall-effect sensors. Then a current-controlled PWM inverter is properly designed to yield excellent armature current tracking control characteristics. As to position control, the dynamic model of the LBDCM drive is first estimated from measurements. Then a two-degrees-of-freedom controller is quantitatively designed to meet the given position-control specifications. A robust controller is designed to reduce the control performance degradation due to system parameter changes and the effect of cogging force. Simulated and measured results are provided to demonstrate the driving performance of the whole linear motor drive View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Robust output tracking control of a linear DC brushless motor for transportation in manufacturing system

    Publication Year: 2001 , Page(s): 119 - 124
    Cited by:  Papers (6)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (560 KB)  

    Robust output tracking control of a linear DC brushless motor for transportation within a manufacturing system is presented. System identification for a linear motor with a driver is performed by a dynamic signal analyser, thus providing a linearised model for the motor. According to the selected nominal parameters, an optimal solution with a prescribed degree of stability is obtained. Due to identification procedures and possible payload variations, parameter uncertainties exist. Thus, an auxiliary input, connected to the nominal optimal control, is introduced to guarantee robustness for the output tracking control problem. A computer simulation and experimental implementation are completed and compared. These results demonstrate the effectiveness of the proposed scheme for output tracking control of the linear DC brushless motor, and also confirm the feasibility of its implementation in industrial applications View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.