Sidney R. Bowes

Simple microprocessor implementation of new regular-sampled harmonic elimination PWM techniques

New harmonic elimination pulse-width-modulation (PWM) strategies for drives and static power converters have recently been developed using modified regular-sampling techniques. These new PWM strategies can be generated online in real time using a simple microprocessor software algorithm, without resorting to the usual offline mainframe computer harmonic elimination numerical techniques. The implementation and generation of these new PWM techniques are presented using the new INMOS transputer, although the same techniques can be performed on any standard 8 bit or 16 bit microprocessor. Results from an experimental transputer-controlled PWM inverter drive are presented to demonstrate and confirm the operation of the new regular-sampled harmonic elimination PWM control strategies.<<ETX>>

Regular-sampled harmonic-elimination PWM control of inverter drives

Novel harmonic elimination PWM strategies for drives, uninterruptible power supplies and static power converters have been developed using modified regular-sampling techniques. These new PWM strategies can be generated on-line in real-time using a simple microprocessor software algorithm, without resorting to the usual time consuming off-line mainframe computer harmonic elimination numerical techniques. These new PWM techniques can be used over the complete voltage/frequency range of the drive up to and including the transition from PWM to quasi-square wave operation. Results from an experimental microprocessor controlled PWM inverter drive are presented to demonstrate and confirm the special feature of the new regular-sampled harmonic elimination PWM control strategies. >

Transputer-based harmonic-elimination PWM control of inverter drives

The implementation and generation of harmonic elimination pulse-width modulation (PWM) techniques using the parallel processing INMOS transputer are presented, and the concurrent programming ability of the transputer for PWM generation is emphasized. The implementation of the PWM strategy can also be performed on any standard 8- or 16-bit microprocessor using four- or one-timer implementation. Results from an experimental transputer-controlled PWM inverter drive are presented to demonstrate and confirm the special feature of the regular-sampled harmonic elimination PWM control strategies.<<ETX>>

New natural observer applied to speed-sensorless DC servo and induction motors

A simple observer design technique with parameter adaptation is proposed for bounded-input bounded-output nonlinear systems. In this technique, no feedback is used in the observer but parameter estimations are considered as if they are observer inputs. The proposed technique is successfully applied to speed-sensorless dc servomotors and speed-sensorless induction motors with load torque adaptation schemes. The observer is robust to noise and parameter uncertainty. Excellent experimental and simulation results have been obtained.

Novel real-time harmonic minimized PWM control for drives and static power converters

This paper shows how a novel harmonic minimized PWM control strategy, based on regular-sampling PWM techniques, can be used to significantly reduce the computational requirements for real-time microprocessor-based PWM implementation. This results in greatly simplified and more efficient microprocessor software/hardware requirements, leading to real-time PWM generation with minimized harmonics, suitable for all power-electronic PWM control applications. >

Transputer-based optimal PWM control of inverter drives

Optimal PWM (pulsewidth-modulated) strategies for voltage source inverter drives have been developed using modified regulator sampling techniques. These strategies can be generated online in real time using a simple algorithm on a microcomputer, without resorting to the usual offline mainframe computer minimization techniques. Using these optimal techniques it is possible to produce a PWM drive performance which closely approximates the optimized PWM performance up to the quasi-square-wave operation. The implementations and generation of these techniques using the Inmos transputer are presented. Results from an experimental transputer-controlled PWM inverter drive are presented to demonstrate and confirm the special feature of the control strategies.<<ETX>>

A universal space vector modulation strategy based on regular-sampled pulse-width modulation [invertors]

A universal space vector modulation (USVM) strategy based on regular-sampled PWM technique is presented which minimizes the switching losses. It is shown that the reduction of the switching losses results from the selected null switching states inverter control. Moreover, it is shown that the simple universal space vector modulation strategy can be implemented in software using a digital signal processor in real-time. Simulation and experimental results are presented to confirm the theoretical analysis.

New robust adaptive control algorithm for high-performance AC drives

This paper presents a new robust structure for a model reference adaptive control (MRAC) controller for field-oriented-controlled (FOC) drives which requires no prior knowledge of the drive parameters and is guaranteed to provide global asymptotic stability of the closed-loop system. This structure simplifies the design and implementation of the adaptive controller requiring less effort to synthesis than a standard MRAC system. Discussion on theoretical aspects, such as selection of a reference model, stability analysis proof, gain adaptive process, steady-state error elimination, and robustness to unmodeled dynamics are included. The paper describes many practical aspects of the implementation, such as adaptive gain analysis, adaptive rate selection, the gain variation limits, gain windup prevention measure, and initial values. The new robust adaptive controller has been successfully implemented on an FOC drive and experiment results for dynamic tracking, sudden loading and unloading, and gains adaptation under different operation conditions are presented to support the robustness of the proposed controller.

Optimal bus-clamped PWM techniques for three-phase motor drives

This paper presents optimal bus-clamped pulse-width modulation (PWM) techniques for three-phase motor drives. The techniques are developed from the viewpoint of per-phase modulation by minimizing the switching loss factor (SLF) [H.W. van der Broeck, 1991], which reflects the inverter switching losses. It is shown that the new optimal bus-clamped PWM techniques dramatically reduce the switching losses and have the minimum switching loss factor in comparison with other existing techniques. Experimental results are presented to confirm the theoretical analysis.

Advanced regular-sampled PWM control techniques for drives and static power converters

Regular-sampled PWM techniques have been developed to reproduce the harmonic-elimination and harmonic minimisation PWM characteristics. These new regular-sampled PWM control strategies significantly reduce the computational requirements for real-time microprocessor-based PWM implementation. This results in simplified and more efficient microprocessor software/hardware requirements, leading to real-time PWM generation with minimised harmonics, suitable for drives and uninterruptible power supplies.<<ETX>>