The Experts below are selected from a list of 51 Experts worldwide ranked by ideXlab platform
Franco Maloberti - One of the best experts on this subject based on the ideXlab platform.
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FEED-FORWARD PATH AND GAIN-SCALING – A SWING AND DISTORTION REDUCTION SCHEME FOR SECOND ORDER SIGMA-DELTA MODULATOR
2016Co-Authors: Wern Ming Koe, Franco MalobertiAbstract:This paper proposed two second-order sigma-delta modulator schemes for reducing the swing at the Output of the first and the second Integrators. The new schemes used feed-forward path to eliminate the term due to the input signal at the Output of the first and second Integrators completely. Hence, the Integrators are processing only the quantization noise that is uncorrelated to the input signal. This paper also proposed a condition for scaling each Integrator gain to further reduce the first Integrator Output swing using gain-scaling technique. Both techniques will make the modulator less sensitive to any harmonic distortion from the opamp used in the Integrator. 1
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feed forward path and gain scaling a swing and distortion reduction scheme for second order sigma delta modulator
International Symposium on Circuits and Systems, 2004Co-Authors: Wern Ming Koe, Franco MalobertiAbstract:This paper proposed a two second-order sigma-delta modulator schemes for reducing the swing at the Output of the first and the second Integrators. The new schemes used feed-forward path to eliminate the term due to the input signal at the Output of the first and second Integrators completely. Hence, the Integrators are processing only the quantization noise that is uncorrelated to the input signal. This paper also proposed a condition for scaling each Integrator gain to further reduce the first Integrator Output swing using gain-scaling technique. Both techniques will make the modulator less sensitive to any harmonic distortion from the opamp used in the Integrator.
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optimization of the Integrator Output swing in low voltage sigma delta modulators
International Symposium on Circuits and Systems, 2001Co-Authors: P Malcovati, Franco MalobertiAbstract:This paper presents a technique which allows us to limit to 0.5 times the reference voltage the Output swing of the first Integrator in a sigma-delta (/spl Sigma//spl Delta/) modulator. The conventional /spl Sigma//spl Delta/ modulator architecture is modified by replacing the global feedback path to the input of the first Integrator with a local feedback. The overall performances of the modulator are maintained by restoring at the Output of the first Integrator the global feedback information by means of a simple additional circuit. The simulation and the experimental results obtained from a prototype implementing a second-order /spl Sigma//spl Delta/ modulator validate the proposed approach.
Wern Ming Koe - One of the best experts on this subject based on the ideXlab platform.
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FEED-FORWARD PATH AND GAIN-SCALING – A SWING AND DISTORTION REDUCTION SCHEME FOR SECOND ORDER SIGMA-DELTA MODULATOR
2016Co-Authors: Wern Ming Koe, Franco MalobertiAbstract:This paper proposed two second-order sigma-delta modulator schemes for reducing the swing at the Output of the first and the second Integrators. The new schemes used feed-forward path to eliminate the term due to the input signal at the Output of the first and second Integrators completely. Hence, the Integrators are processing only the quantization noise that is uncorrelated to the input signal. This paper also proposed a condition for scaling each Integrator gain to further reduce the first Integrator Output swing using gain-scaling technique. Both techniques will make the modulator less sensitive to any harmonic distortion from the opamp used in the Integrator. 1
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feed forward path and gain scaling a swing and distortion reduction scheme for second order sigma delta modulator
International Symposium on Circuits and Systems, 2004Co-Authors: Wern Ming Koe, Franco MalobertiAbstract:This paper proposed a two second-order sigma-delta modulator schemes for reducing the swing at the Output of the first and the second Integrators. The new schemes used feed-forward path to eliminate the term due to the input signal at the Output of the first and second Integrators completely. Hence, the Integrators are processing only the quantization noise that is uncorrelated to the input signal. This paper also proposed a condition for scaling each Integrator gain to further reduce the first Integrator Output swing using gain-scaling technique. Both techniques will make the modulator less sensitive to any harmonic distortion from the opamp used in the Integrator.
Jangmok Kim - One of the best experts on this subject based on the ideXlab platform.
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dead time compensation method for voltage fed pwm inverter
IEEE Transactions on Energy Conversion, 2010Co-Authors: Seonhwan Hwang, Jangmok KimAbstract:A new dead time compensation method for a pulsewidth modulation (PWM) inverter is proposed. In the PWM inverter, voltage distortion due to the dead time effects produces fifth and seventh harmonics in the phase currents of the stationary reference frame, and a sixth harmonic in the d- and q-axis currents of the synchronous reference frame, respectively. In this paper, the sixth harmonic of the Integrator Output of the synchronous d-axis proportional-integral (PI) current regulator is used to compensate the Output voltage distortion due to the dead time effects, since the Integrator Output has ripple corresponding to six times the stator fundamental frequency. The proposed method can be easily implemented by feedforwardly adding compensation voltages to the Output reference voltage of the synchronous PI current regulator. The proposed method, therefore, has some significant advantages such as simple implementation without additional hardware, easy mathematical computation, no offline experimental measurements, and application in both the steady state and the transient state. The validity of the proposed compensation algorithm is shown through several experiments.
Dongsoo Kwon - One of the best experts on this subject based on the ideXlab platform.
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a nonlinear friction compensation method using adaptive control and its practical application to an in parallel actuated 6 dof manipulator
Control Engineering Practice, 2001Co-Authors: Jeehwan Ryu, Jinil Song, Dongsoo KwonAbstract:This paper presents a simple and e!ective nonlinear friction compensation method which is derived from an adaptive control strategy and its practical application to a linear actuator. The proposed adaptive friction compensation method is shown to be equivalent to the reversed integral controller that is easily applied to the conventional PID controller. The reversed integral controller reverses the sign of the Integrator Output as the sign of the velocity changes. It analyzes how the reversed control action can compensate for friction. The e!ectiveness of this approach is demonstrated by experiments on a 3-PRPS (Prismatic-Revolute-Prismatic-Spherical joints) in-parallel 6-DOF manipulator. ( 2001 Published by Elsevier Science ‚td. All rights reserved.
Seonhwan Hwang - One of the best experts on this subject based on the ideXlab platform.
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dead time compensation method for voltage fed pwm inverter
IEEE Transactions on Energy Conversion, 2010Co-Authors: Seonhwan Hwang, Jangmok KimAbstract:A new dead time compensation method for a pulsewidth modulation (PWM) inverter is proposed. In the PWM inverter, voltage distortion due to the dead time effects produces fifth and seventh harmonics in the phase currents of the stationary reference frame, and a sixth harmonic in the d- and q-axis currents of the synchronous reference frame, respectively. In this paper, the sixth harmonic of the Integrator Output of the synchronous d-axis proportional-integral (PI) current regulator is used to compensate the Output voltage distortion due to the dead time effects, since the Integrator Output has ripple corresponding to six times the stator fundamental frequency. The proposed method can be easily implemented by feedforwardly adding compensation voltages to the Output reference voltage of the synchronous PI current regulator. The proposed method, therefore, has some significant advantages such as simple implementation without additional hardware, easy mathematical computation, no offline experimental measurements, and application in both the steady state and the transient state. The validity of the proposed compensation algorithm is shown through several experiments.
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diminution of current measurement error for vector controlled ac motor drives
IEEE Transactions on Industry Applications, 2006Co-Authors: Hansu Jung, Seonhwan Hwang, Cheol Woong ChoiAbstract:The errors generated from the current-measurement path are inevitable, and they can be divided into two categories: offset errors and scaling errors. Current data including these errors cause the periodic rotor speed ripples, which are one and two times the fundamental stator current frequency. Since these undesirable ripples can harm the motor drive system, a compensation algorithm must be included in the motor control drive. In this paper, a new compensation algorithm is proposed. The principal feature of the proposed algorithm is the use of the Integrator Output signal of the d-axis proportional plus integral (PI) current regulator. This Output signal is nearly zero or constant because the d-axis current command is zero or constant, so that the maximum torque or unity power factor can be acquired in the ac drive system. If the stator currents include offset and scaling errors, the Integrator Output signal of the d-axis PI current regulator ripples in the rotor speed of the same frequency. The proposed compensating algorithm for the current-measurement errors can be easily implemented by subtracting the dc offset value or rescaling the input measurement gain of the stator currents. Therefore, the proposed algorithm has several advantages: it is robust with regard to the variation of the motor parameters; it is applicable to steady and transient states; it is easy to implement; and it requires less computation time. The MATLAB simulation and the experimental results verify the usefulness of the proposed current compensating algorithm