K.M. Tsang

The Hong Kong Polytechnic University, Hong Kong, Hong Kong

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Publications (52)85.44 Total impact

  • H.Y. Li, Y.K. Wong, W.L. Chan, K.M. Tsang
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    ABSTRACT: In this paper, an adaptive neural network H∞ control is proposed to realize the synchronization of two Ghostburster neurons under external electrical stimulation. We first analyze the periodic and chaotic dynamics of individual Ghostburster neuron under different external electrical stimulations, then design a H∞ controller via adaptive neural networks to synchronize two Ghostburster neurons and drive the slave neuron to act as the master one. Asymptotic synchronization can be obtained by proper choice of the control parameters. Simulation results demonstrate the effectiveness of the proposed control method.
    Neurocomputing 12/2010; · 2.01 Impact Factor
  • Nuo Li, Y.K. Wong, W.L. Chan, K.M. Tsang
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    ABSTRACT: Power spectral analysis is a traditional method used for EEG analysing. In this paper, Welch method was used to process the signals obtained from a carefully designed acupuncture experiment. The main objective of this work is to find the effect of acupuncture on brain. A protocol composed of three different manipulations has been designed to acquire the EEG signals using 22 biosensors. Totally 9 healthy volunteers with an age group of 23-27 years old have been used in this acupuncture experiment and ANOVA test was adopt to reveal the differences among several acupuncture stages. At last, an apparent phenomenon was found in the study.
    Automation and Logistics (ICAL), 2010 IEEE International Conference on; 09/2010
  • K.M. Tsang, W.L. Chan
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    ABSTRACT: A simple equivalent series inductance (ESL) and equivalent series resistance (ESR) measurement technique for capacitors is presented. A low-cost square waveform voltage source coupled with a reference resistor can be used to measure the ESL, ESR and capacitance of an electrolytic capacitor. By connecting a capacitor in series with a reference resistor, the equivalent output step response of the capacitor voltage reveals the ESL and ESR of the capacitor. To effectively capture the output step response, a square input waveform is used instead. The square waveform voltage source can easily be realised using a DC voltage source and simple switching devices. Experimental results are included to demonstrate the effectiveness of the proposed scheme.
    IET Power Electronics 08/2010; · 1.32 Impact Factor
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    ABSTRACT: We consider the assumption of existence of the general nonlinear internal model that is introduced in the design of robust output regulators for a class of minimum-phase nonlinear systems with rth degree (r ≥ 2). The robust output regulation problem can be converted into a robust stabilisation problem of an augmented system consisting of the given plant and a high-gain nonlinear internal model, perfectly reproducing the bounded including not only periodic but also nonperiodic exogenous signal from a nonlinear system, which satisfies some general immersion assumption. The state feedback controller is designed to guarantee the asymptotic convergence of system errors to zero manifold. Furthermore, the proposed scheme makes use of output feedback dynamic controller that only processes information from the regulated output error by using high-gain observer to robustly estimate the derivatives of the regulated output error. The stabilisation analysis of the resulting closed-loop systems leads to regional as well as semi-global robust output regulation achieved for some appointed initial condition in the state space, for all possible values of the uncertain parameter vector and the exogenous signal, ranging over an arbitrary compact set.
    International Journal of Control 05/2010; 83(5):1009-1024. · 1.14 Impact Factor
  • K. M. Tsang, W. L. Chan
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    ABSTRACT: A new approach using polynomial predictive filters and fuzzy logic for the online validation of sensor measurements is proposed. Polynomial predictive filters are applied to measured data records during the fault free learning stage. Predictions derived from the predictive filters are compared with the actual measurements to generate an error sequence. Fuzzy rules are then derived from the error sequence together with the physical constraints of a sensor to classify the quality of measurements. Faulty measurements can then be picked up by the fuzzy detection rules to ensure the correctness of measurements. Experimental results for detecting the quality of measurements from a temperature sensor are presented.
    Sensors and Actuators A Physical 05/2010; 159(2):149-156. · 1.94 Impact Factor
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    ABSTRACT: In this paper different topologies of populations of FitzHugh-Nagumo neurons have been introduce to investigate the effect of high-frequency driving on the response of neuron populations to a subthreshold low-frequency signal. We show that optimal amplitude of high-frequency driving enhances the response of neuron populations to a subthreshold low-frequency input and the optimal amplitude dependences on the connection among the neurons. By analyzing several kinds of topology (i.e., random and small world) different behaviors have been observed. Several topologies behave in an optimal way with respect to the range of low-frequency amplitude leading to an improvement in the stimulus response coherence, while others with respect to the maximum values of the performance index. However, the best results in terms of both the suitable amplitude of high-frequency driving and high stimulus response coherence have been obtained when the neurons have been connected in a small-world topology.
    Chaos (Woodbury, N.Y.) 03/2010; 20(1):013113. · 1.76 Impact Factor
  • K. M. Tsang, L. Sun, W. L. Chan
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    ABSTRACT: A universal battery model for the charging process has been identified for Lithium ion battery working at constant temperature. Mathematical models are fitted to different collected charging profiles using the least squares algorithm. With the removal of the component which is related to the DC resistance of the battery, a universal model can be fitted to predict profiles of different charging rates after time scaling. Experimental results are included to demonstrate the goodness of fit of the model at different charging rates and for batteries of different capacities. Comparison with standard electrical-circuit model is also presented. With the proposed model, it is possible to derive more effective way to monitor the status of Lithium ion batteries, and to develop a universal quick charger for different capacities of batteries to result with a more effective usage of Lithium ion batteries.
    Energy Conversion and Management - ENERG CONV MANAGE. 01/2010; 51(12):2857-2862.
  • K. M. Tsang, W. L. Chan, Y. K. Wong, L. Sun
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    ABSTRACT: Lithium-ion batteries are very popular nowadays. In order to design and evaluate the performance of systems involving batteries, good models are required for systems simulation. In this paper, popular lithium-ion battery models are investigated and presented. Selection of appropriate models for a particular simulation will also be presented.
    01/2010;
  • X.L. Wei, K.M. Tsang, W.L. Chan
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    ABSTRACT: An internal model control with conditional integrator is proposed for the robust output regulation of single-switch quadratic buck converters. The output regulation problem of a quadratic buck converter is converted to the stabilisation of an augmented system consisting of the buck converter and the internal model. The design procedures include the design of an internal model with conditional integrator and a robust state feedback stabiliser with saturation behaviour. The closed-loop stability of the converter will be theoretically analysed. Finally, the effectiveness of the proposed control scheme for large load and supply variations are also tested. The design of the controller does not require the exact circuit parameters and the stability proof demonstrates the robustness against parameter uncertainties.
    IET Power Electronics 10/2009; · 1.32 Impact Factor
  • K.M. Tsang, W.L. Chan
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    ABSTRACT: A simple equivalent series resistance (ESR) measurement technique for capacitors at high current and high frequency is presented. A low-cost square waveform voltage source coupled with a reference resistor can be used to measure the ESR of an electrolytic capacitor. By connecting a capacitor in series with a reference resistor, the ratio of the voltage magnitude across the capacitor to the voltage magnitude of the supply voltage reveals the ESR of the capacitor if the frequency of the supply source is sufficiently high. The square waveform voltage source can easily be realised using a DC voltage source and simple switching devices. An addition of a small inductor in series with the reference resistor could eliminate the effect of the equivalent series inductance and improve the measurement accuracy. A mathematical analysis is presented to demonstrate that the use of the square waveform and the addition of the small inductor are valid. Experimental results are included to demonstrate the effectiveness of the proposed scheme.
    IET Power Electronics 10/2009; · 1.32 Impact Factor
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    ABSTRACT: Intermodulation and harmonics are important in frequency analysis of nonlinear systems. In neuron research, most investigations are taken in studying synchronization between the external stimuli and the output of neuron, but harmonics and intermodulation are often ignored. In this paper, harmonics and intermodulation of the subthreshold FitzHugh-Nagumo neuron are investigated and their magnitudes are used to predict frequency response of the neuron. Furthermore, through analyzing the magnitudes of harmonics, the intrinsic frequencies of the neuron could be identified.
    Chaos (Woodbury, N.Y.) 09/2009; 19(3):033144. · 1.76 Impact Factor
  • K. M. Tsang, W. L. Chan
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    ABSTRACT: Inductor current sensing is very important in the control and monitoring of switching power converters. Traditional low cost implementation using a sensing resistor in series with the inductor will reduce the overall efficiency of the power converter. Conventional Hall effect current sensor could also be used to detect the inductor current. However, it will significantly increase the production cost of power converters. One simple and low cost implementation is to add a resistor–capacitor (RC) network in parallel with the inductor so that the inductor current can be derived from the added circuitry. The problem with RC sensing network is that the sensed variable is very sensitive to temperature variations. In this paper, a novel inductor current sensor using low cost negative temperature coefficient (NTC) thermistors to compensate the variation in the parasitic resistance of the inductor due to temperature changes is proposed. The changes in the cutoff frequency and steady state gain are also compensated by the added NTC thermistor circuit. With the compensated network, the sensed inductor current derived from the modified RC network will be independent of temperature variations. The compensated network can be applied to inductors fitted to power converters. Although experimental studies based on a buck converter were carried out to illustrate the correctness of the improved sensing technique, the proposed technique is applicable to other converter topologies.
    Sensors and Actuators A Physical 08/2009; 154(1):16-22. · 1.94 Impact Factor
  • K. M. Tsang, W. L. Chan
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    ABSTRACT: A simple low-cost battery charger based on a saturated controller is proposed for charging of lithium-ion (Li-ion) batteries. When the reference voltage of the closed-loop process is set to 4.2V, the charging process resembles a constant-current and constant-voltage (CC–CV) charging strategy. The charging process can easily be shortened by raising the limit on the saturated controller. Experimental results are included to demonstrate the effectiveness of the charger. It is anticipated that the charger can be a low-cost high-performance replacement of existing Li-ion battery chargers.
    Journal of Power Sources 06/2009; 191(2):633-635. · 5.21 Impact Factor
  • Xile Wei, K. M. Tsang, W. L. Chan
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    ABSTRACT: An internal model control with a conditional integrator is proposed for the robust output regulation of a DC/DC buck converter. Based on the input–output linearization from the state-space averaged model of DC/DC buck converter, the robust output regulation problem of the converter can be converted into a robust stabilization problem of an augmented system consisting of the given buck converter and the internal model by introducing a proper internal model. The procedures include the design of an internal model with conditional integrator and a sliding-mode robust controller. Also the closed-loop robust stability is theoretically analyzed. Finally, the effectiveness of the proposed converter is verified in comparing the proposed controller performance with open-loop control, single-loop proportional-plus-integral control, and double-loop proportional-plus-integral control under load disturbances and supply voltage variations.
    Electric Power Components and Systems 03/2009; 37(3):320-330. · 0.66 Impact Factor
  • K. M. Tsang, W. L. Chan
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    ABSTRACT: One of the key components in the current mode control of power converters is the sensing of inductor current. Traditional low cost implementation is to add a sensing resistor in series with the inductor to sense the inductor current. This will reduce the overall efficiency of the power converter. An alternative is to apply a current transformer to the inductor to sense its current. This however will significantly increase the cost of power converters. One low cost implementation is to add a resistor–capacitor network in parallel with the inductor so that the inductor current can be derived from the capacitor voltage. The problem of this implementation is that the capacitor voltage is very sensitive to temperature variations. In this paper, a simple feedback loop is applied to the sensed capacitor voltage based on the steady state duty ratio of power converters such that the sensed inductor current will be independent of temperature variations. The sensing element with feedback compensation can be applied to inductors fitted to power converters such as buck converters and boost converters. Although experimental studies based on a buck converter were carried out to illustrate the correctness of the new sensing technique, the proposed technique is applicable to other converter topologies.
    Sensors and Actuators A Physical 01/2009; 149(1):81-86. · 1.94 Impact Factor
  • K. M. Tsang, W. L. Chan
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    ABSTRACT: A model-based cascade controller design is presented for the control of DC/DC Buck converters. Detailed discussions in the setting of bandwidth for the current loop and voltage loop have been given. Robustness analysis of the cascade controller against load changes and supply changes are also presented. Finally, a deadband relay is introduced in the voltage loop to improve the disturbance rejection and speed of response of the Buck converter. Circuit implementation of the proposed control scheme is presented, and experimental results are included to demonstrate the effectiveness of the proposed design scheme. Comparisons with conventional single-loop proportional-plus-integral control and cascade control are also made.
    Electric Power Components and Systems 08/2008; 36(9):977-989. · 0.66 Impact Factor
  • K. M. Tsang, W. L. Chan
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    ABSTRACT: The paper presents the design of a sensing system for non-destructive inspection of the health condition of wooden poles for overhead power lines. Acoustic impulse responses are collected for the analysis of the condition of different wooden poles. The concept of cumulative energy spectrum for feature extraction is introduced. Fuzzy logic is also used to solve the problem of small samples. Experimental results and the accuracy of the method are also presented.
    Sensors and Actuators A Physical 05/2008; 143(2):251-255. · 1.94 Impact Factor
  • K.M. Tsang, W.L. Chan, X.L. Wei
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    ABSTRACT: An internal model control using a conditional integrator compensator is proposed for the robust output regulation of a DC/DC buck converter. Based on the input-output linearisation from the state-space averaged model of the DC/DC buck converter, the robust output regulation problem of this type of converter can be converted into a robust stabilisation problem of an augmented system consisting of the given buck converter and the internal model by introducing a proper internal model. Another advantage of the proposed method is to sense the capacitor current instead of the inductor current. The effectiveness of the proposed converter is verified by comparing the proposed controller performance with single-loop PI control and double-loop PI control under load disturbances and supply voltage variations.
    Electronics Letters 02/2008; · 1.07 Impact Factor
  • K.M. Tsang, W.L. Chan
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    ABSTRACT: A simple, fast detection scheme for voltage dip and voltage swell is presented. Applying a simple relay and lowpass filter to the supply voltage signal, an in-phase fixed magnitude reference signal with very low total harmonic distortion can be generated. Comparing the supply signal with the in-phased fixed magnitude reference sinusoid, any change of magnitude in the supply signal can be detected. The detection scheme can indicate voltage dip and voltage swell in less than a quarter of the cycle of oscillation. Experimental results are presented to demonstrate the effectiveness of the proposed detection scheme
    Electronics Letters 02/2007; · 1.07 Impact Factor
  • K. M. Tsang, W. L. Chan
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    ABSTRACT: A simple design method for power factor correction (PFC) boost converter is presented in this article. Model based cascade controller design is presented for the control of PFC boost converters. Detail discussions in the setting of bandwidth for the current loop and voltage loop have been given. Finally, a deadband relay is introduced in the voltage loop to improve the disturbance rejection and speed of response of the PFC boost converter. Circuit implementation of the proposed control scheme is presented and experimental results are included to demonstrate the effectiveness of the proposed design scheme. The resultant power factor is over 0.99, the total harmonic distortion of supply current is less than 2.9% and the efficiency of the converter is 93% at full load.
    Electric Power Components and Systems 12/2006; 34(12):1267-1282. · 0.66 Impact Factor

Publication Stats

149 Citations
85.44 Total Impact Points

Institutions

  • 2001–2014
    • The Hong Kong Polytechnic University
      • Department of Electrical Engineering
      Hong Kong, Hong Kong
  • 2005–2010
    • The University of Hong Kong
      • Department of Electrical and Electronic Engineering
      Hong Kong, Hong Kong
  • 2003–2010
    • Tianjin University
      • School of Electrical Engineering and Automation
      Tianjin, Tianjin Shi, China
    • Harbin Engineering University
      Charbin, Heilongjiang Sheng, China