EPE Association: EPE-PEMC 2002: Special Session: Sliding Mode Control of Drives

EPE-PEMC 2002: Special Session: Sliding Mode Control of Drives
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   A modified approach to the design of robust speed and position control of servo drives
By S. Brock; K. Zawirski; J. Deskur [View]
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Abstract: In the paper a robust control of position servodrives is analysed. A modified approach to design robust speed and position controller is proposed, which leads to a trajectory of motion invariant to load torque and system parameters variations The proposed controller structure consists of nonlinear controller of position, speed and acceleration and optional sliding mode controller, operating with reference model. Simple formulas for controller settings, given in the paper, ensure good robustness even if roughly estimated system parameters are used. Performed experimental investigations verified theoretical results and prove good quality of control.

   Integral Variable Structure Controller for a Variable Speed Induction Generator Driven by a Wind Turbine
By R. Cárdenas; R. Pena; D. Sbarbaro [View]
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Abstract: In this paper a simple strategy is presented to track the optimum operating point of a vector controlled cage induction generator driven by a wind turbine. The scheme is based on variable structure controller with integral compensation. The integral compensation provides zero error in steady state for step reference signals and either reduces or eliminates the control signal chattering. Experimental results, from an emulated 3.2kW wind energy system, are given and some practical aspects, like tuning and controller wind-up, are also considered.

   Shifted sliding surface for a DC motor drive
By F. Betin; D. Pinchon; A. Sivert [View]
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Abstract: In this paper, a new variable structure position control law for a DC motor is proposed. The algorithm based on a time-varying switching line guarantees the existence of a sliding mode since the beginning of the shaft motion. Indeed, the surface is initially designed to pass through the initial representative point and subsequently moved towards a predetermined desired surface by shifting. By this mean, the reaching phase is eliminated and the motor behaviour is insensitive to unknown mechanical configuration changes. The algorithm has been tested in simulation and the experiment has been performed using a low-cost 16-bit microcontroller. An advanced test bed is used in order to evaluate the robustness capacities of the proposed controller.

   Sliding Mode Approach in Speed Sensorless Control of an Induction Motor
By G. Edelbaher; A. Sabanovic; K. Jezernik [View]
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Abstract: Sensorless control of induction motor (IM) drives has received wide attention in last few years. The main reason is that the use of speed sensor spoils the ruggedness and simplicity of IM. Even more, in a hostile environment speed sensors cannot be mounted. However, due to the high order and nonlinearity of the dynamics of an IM, estimation of the angle speed and rotor flux without the measurement of mechanical variables becomes a challenging problem. To overcome this, various speed sensorless control algorithms have been presented. Due to its order reduction, disturbance rejection, strong robustness, and simple implementation by the means of power converter and digital signal processors, sliding mode control (SMC) theory is one of the prospective control methodologies for electric machines. In this paper, an SMC based rotor flux observer is designed and a sliding mode approach is applied to the torque tracking control of the IM. In principle, the proposed method is based on driving the stator flux towards the reference stator flux vector defined by the input commands, the reference torque and the reference rotor flux. This action is carried out by the robust sliding mode flux controller applying a suitable stator voltage vector to the machine in order to compensate the stator flux vector error. Sensorless torque and flux control of an IM is an emerging new technology, though in the early state of development. A sliding mode algorithm for torque and flux tracking control is presented in the paper. The algorithm is aimed to solve practical highly nonlinear problem of the operation of IM at high and low speed including zero speed. This algorithm is especially suitable for the applications where desired torque and rotor flux are varying during the operation. For example when efficiency of the IM operation is an important issue, like in electric vehicles. The performance of the proposed algorithm was verified by the simulations and experiments.

   Sliding-Mode Torque Control and Observer Design for an Induction Machine
By M. W. Dunnigan; F. Chen [View]
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Abstract: In this paper a novel sliding-mode control algorithm, based on differential geometry feedback linearization control theory, is proposed to decouple the control of rotor flux magnitude and motor torque. The advantages of this method are: 1) The generated torque becomes a linear output with respect to the control states 2) The rotor flux and the generated torque can be accurately controlled 3) Robustness with respect to matched and mismatched uncertainties is obtained. Additionally, a varying continuous control term is proposed, which eliminates chattering. The control strategy is based on all motor states being available. In practice the rotor fluxes are not usually measurable, and a robust sliding-mode observer is derived to estimate the rotor flux. The observer is designed to possess invariant dynamic modes which can be assigned independently to achieve the desired performance. Experimental results are presented to confirm the characteristics of the proposed control law and rotor flux observer.

EPE-PEMC 2002: Special Session: Sliding Mode Control of Drives
You are here: EPE Documents > 04 - EPE-PEMC Conference Proceedings > EPE-PEMC 2002 - Conference > EPE-PEMC 2002: Special Session: Sliding Mode Control of Drives
	[return to parent folder]

	A modified approach to the design of robust speed and position control of servo drives By S. Brock; K. Zawirski; J. Deskur	[View] [Download]
Abstract: In the paper a robust control of position servodrives is analysed. A modified approach to design robust speed and position controller is proposed, which leads to a trajectory of motion invariant to load torque and system parameters variations The proposed controller structure consists of nonlinear controller of position, speed and acceleration and optional sliding mode controller, operating with reference model. Simple formulas for controller settings, given in the paper, ensure good robustness even if roughly estimated system parameters are used. Performed experimental investigations verified theoretical results and prove good quality of control.

	Integral Variable Structure Controller for a Variable Speed Induction Generator Driven by a Wind Turbine By R. Cárdenas; R. Pena; D. Sbarbaro	[View] [Download]
Abstract: In this paper a simple strategy is presented to track the optimum operating point of a vector controlled cage induction generator driven by a wind turbine. The scheme is based on variable structure controller with integral compensation. The integral compensation provides zero error in steady state for step reference signals and either reduces or eliminates the control signal chattering. Experimental results, from an emulated 3.2kW wind energy system, are given and some practical aspects, like tuning and controller wind-up, are also considered.

	Shifted sliding surface for a DC motor drive By F. Betin; D. Pinchon; A. Sivert	[View] [Download]
Abstract: In this paper, a new variable structure position control law for a DC motor is proposed. The algorithm based on a time-varying switching line guarantees the existence of a sliding mode since the beginning of the shaft motion. Indeed, the surface is initially designed to pass through the initial representative point and subsequently moved towards a predetermined desired surface by shifting. By this mean, the reaching phase is eliminated and the motor behaviour is insensitive to unknown mechanical configuration changes. The algorithm has been tested in simulation and the experiment has been performed using a low-cost 16-bit microcontroller. An advanced test bed is used in order to evaluate the robustness capacities of the proposed controller.

	Sliding Mode Approach in Speed Sensorless Control of an Induction Motor By G. Edelbaher; A. Sabanovic; K. Jezernik	[View] [Download]
Abstract: Sensorless control of induction motor (IM) drives has received wide attention in last few years. The main reason is that the use of speed sensor spoils the ruggedness and simplicity of IM. Even more, in a hostile environment speed sensors cannot be mounted. However, due to the high order and nonlinearity of the dynamics of an IM, estimation of the angle speed and rotor flux without the measurement of mechanical variables becomes a challenging problem. To overcome this, various speed sensorless control algorithms have been presented. Due to its order reduction, disturbance rejection, strong robustness, and simple implementation by the means of power converter and digital signal processors, sliding mode control (SMC) theory is one of the prospective control methodologies for electric machines. In this paper, an SMC based rotor flux observer is designed and a sliding mode approach is applied to the torque tracking control of the IM. In principle, the proposed method is based on driving the stator flux towards the reference stator flux vector defined by the input commands, the reference torque and the reference rotor flux. This action is carried out by the robust sliding mode flux controller applying a suitable stator voltage vector to the machine in order to compensate the stator flux vector error. Sensorless torque and flux control of an IM is an emerging new technology, though in the early state of development. A sliding mode algorithm for torque and flux tracking control is presented in the paper. The algorithm is aimed to solve practical highly nonlinear problem of the operation of IM at high and low speed including zero speed. This algorithm is especially suitable for the applications where desired torque and rotor flux are varying during the operation. For example when efficiency of the IM operation is an important issue, like in electric vehicles. The performance of the proposed algorithm was verified by the simulations and experiments.

	Sliding-Mode Torque Control and Observer Design for an Induction Machine By M. W. Dunnigan; F. Chen	[View] [Download]
Abstract: In this paper a novel sliding-mode control algorithm, based on differential geometry feedback linearization control theory, is proposed to decouple the control of rotor flux magnitude and motor torque. The advantages of this method are: 1) The generated torque becomes a linear output with respect to the control states 2) The rotor flux and the generated torque can be accurately controlled 3) Robustness with respect to matched and mismatched uncertainties is obtained. Additionally, a varying continuous control term is proposed, which eliminates chattering. The control strategy is based on all motor states being available. In practice the rotor fluxes are not usually measurable, and a robust sliding-mode observer is derived to estimate the rotor flux. The observer is designed to possess invariant dynamic modes which can be assigned independently to achieve the desired performance. Experimental results are presented to confirm the characteristics of the proposed control law and rotor flux observer.