Switching Control Approach Research Articles

A new approach to the design of mode switching control in hard disk drive servo systems

In a modern large-capacity magnetic hard disk drive (HDD), both fast track seeking and perfect positioning of the read/write head are required. Mode switching control (MSC) approaches are widely used to meet these requirements. This paper proposes a new approach in designing MSC with an application to HDD servo systems. The proposed scheme uses a proximate time-optimal servomechanism in the track seeking mode, and a robust perfect tracking (RPT) controller in the track following mode. Unlike the conventional MSC approaches, the new method does not require an initial value compensation during mode switching. This is because the RPT controller in the second stage is capable of rendering the Lp-norm ð1ppoNÞ of the resulting tracking error arbitrarily small in the presence of external disturbances and initial conditions. Simulation and experimental results show that the proposed method improves the seek and settling time by about 10% over the conventional approaches. r 2002 Elsevier Science Ltd. All rights reserved.

Robust hysteresis current-controlled PWM scheme with fixed switching frequency

A robust hysteresis current-controlled PWM scheme is presented, having constant switching frequency for a single-phase inverter with a wide frequency range. An intuitive analysis for the harmonic spectrum characteristic of the hysteresis control PWM inverter is made prior to developing the proposed switching control approach. According to the operating frequency and load nature of inverter, the variation range of the hysteresis band for achieving the desired constant switching frequency is determined, and the hysteresis switching mechanism is devised. Next, the filter design, in accordance with the inverter output frequency feature and the load requirement, is described. In addition, a simple robust controller is proposed to improve the constant frequency control performance and thus to reduce the effect of inverter output harmonics on the load operating characteristics. The proposed hysteresis PWM scheme is applied to an inverter-fed electrodynamic shaker, and its effectiveness is verified by simulation and experimental results.

Localization based switching adaptive control for time-varying discrete-time systems

In this paper a new systematic switching control approach to adaptive stabilization of linear time-varying (LTV) discrete-time systems is presented. A feature of the localization based method is its high model falsification capability, which in the case of LTI systems is manifested as the rapid convergence of the switching controller. We believe that the proposed method may help pave the way for design of practical adaptive switching controllers applicable to a wide range of linear time-invariant and time-varying systems.

Design and implementation of a single phase three-arms rectifier inverter

A high performance single phase three-arms PWM rectifier inverter is presented. A switching control approach for the common arm is proposed such that control of the rectifier arm and inverter arm can be designed independently. Variable structure control (VSC) executed with capacitor current control is developed to design the inverter. For the rectifier design, an instantaneous power feedback controller using filter theory is proposed to enhance the DC voltage regulator to reduce DC voltage fluctuation and minimise input current distortion. A 3 kVA system is implemented to confirm the effectiveness of the proposed approaches.