A.M. Stankovic

Multifunctional Six-Phase Motor Drives with Algorithms of Synchronized PWM

Novel methodology of synchronized pulsewidth modulation (PWM) has been disseminated for control of six-phase (dual-three phase) induction machine drives fed by two three-phase inverters with both single and separate DC voltage sources. Control algorithms are based in this case on the 30deg-phase-shifting of control and output signals of two standard voltage source inverters. Four basic schemes of synchronized PWM, applied for control of six-phase drives, have been analyzed and compared. Simulations results are given for continuous, discontinuous and combined versions of synchronized PWM. The spectra of the phase voltage of the six-phase drives with algorithms of synchronized PWM do not contain even harmonics and sub-harmonics, which is especially important for the high power/current applications

Low torque ripple control of current-fed switched reluctance motors

The paper addresses a basic control issue in switched reluctance motor (SRM) drives-the production of ripple-free torque. Simple and largely model-independent conventional switching patterns are not able to satisfy this requirement. Our goal is to improve SRM dynamical performance by compensating for motor nonlinearities while maintaining the robustness of conventional methods in a simple position and current feedback. Our method is based on a complete parametrization of position dependent voltage and current profiles in ripple free operation and waveform optimization to minimize power supply requirements. We allow for model uncertainties and show that our strategy consistently outperforms the conventional policy. Experimental data verifying the analytical approach are included, and implications for self-tuning and shaft sensorless operation are outlined.

Analysis and Comparison of Basic Schemes of Synchronized PWM for Dual Inverter-Fed Drives

Two basic schemes of synchronized pulsewidth modulation (PWM) have been disseminated for control of dual inverter-fed open-end winding induction motor drives with full elimination of the common-mode voltages. The algorithms of synchronized PWM provide symmetry of the phase voltage of the system during the whole control range including the zone of overmodulation. Spectra of the motor phase voltage of dual inverter-fed drives do not contain even harmonics and sub-harmonics (combined harmonics), which is especially important for the systems with increased power rating. Analysis of processes in drive systems with two schemes of synchronized PWM, based on the modelling and simulations, has been done

Synchronized PWM scheme for dual inverter-fed drives with zero common-mode voltages

Novel method of direct synchronized pulsewidth modulation is applied for control of a dual inverter-fed open-end winding induction motor drive with zero common-mode voltages. New strategy and algorithms of synchronized PWM provide symmetry of the phase voltage of the system during the whole control range including the zone of overmodulation. Spectra of the phase voltage do not contain even harmonics and sub-harmonics (combined harmonics), which is especially important for the drive systems with increased power rating. Simulations gave the behaviour of dual inverter-fed system with the proposed synchronized PWM scheme

Operation of Six-Phase Drives with Synchronized PWM in the Overmodulation Region

Analysis of operation of the six-phase (dual three-phase) drives with basic schemes of synchronized pulsewidth modulation (PWM) in the zone of overmodulation has been performed. Control of six-phase drives is based on the 30deg-phase-shifting between signals of two standard inverters, supplied from a single DC voltage source. Algorithms of synchronized PWM provide continuous synchronization of the output voltage waveforms of each inverter. The four-level phase voltage of six-phase drives has quarter-wave symmetry during control in this zone. Continuous and discontinuous versions of synchronized PWM, based on space-vector approach for determination of the pulse patterns, have been analyzed and compared by simulations of drive systems with low switching frequencies.

Dissipativity-based control of PM synchronous motors with guaranteed convergence rates

This paper describes a control design procedure that enables a permanent magnet synchronous motor (PMSM) to track time-varying load torque and commanded velocity. The controller aims at the optimal shaping of steady-state operation, global stability of the desired setpoint, and guaranteed exponential decay rates for transients between specified operating points. It also eliminates the inherent gap between the electrical and the mechanical time constants concurrently achieving improved performance and reduced power supply requirements.

Direct time-domain-based approach for study of space-vector pulsewidth modulation

D irect time-domain-based approach, which is characterized by the simplicity and clarity, is proposed for the study and design of space-vector based methods of pulsewidth modulation (PWM) for standard voltage source inverters for adjustable speed motor drives. This approach is based on the detailed consideration of switching state sequences of three- phase inverter (with the corresponding duty-cycles), which are integrated characteristics of space vector PWM schemes and versions. It also permits providing of synchronization of output voltage waveforms and improvement of computational effectiveness of control algorithms.

Analysis of control regimes of three-level inverters with synchronized space-vector modulation

The paper describes operation of three-level inverters with synchronized pulsewidth modulation (PWM) at control regimes different from standard volts/hertz control. Control algorithms provide common-mode voltage cancellation in three-phase load in this case. The output voltage of converters has quarter-wave symmetry during the whole control range including the zone of overmodulation. Simulations give the behaviour of different versions of synchronous PWM.

Synchronous control of multilevel cascaded converters with separate DC-link sources

Novel method of direct synchronised pulsewidth modulation is applied for control of a dual inverter-fed open-end winding induction motor drive with separate DC-link sources with different voltages. New strategy and algorithms of synchronised pulsewidth modulation (PWM) provide quarter-wave symmetry of multilevel actual phase voltage of the system during the whole control range including the zone of over modulation. Spectra of the actual phase voltage do not contain even harmonics and sub-harmonics, which is especially important for the drive systems with increased power rating. Simulations gave the behavior of dual inverter-fed drives with synchronised modulation for the drive topologies with both equal and different DC-link voltages

Synchronization of Voltage Waveforms in Basic Topologies of Dual Inverter-Fed Motor Drives

This paper presents results of application of novel methods of synchronized pulse width modulation (PWM) to the open-end winding induction motor drives on the base of dual two-level voltage source inverters, with both single and separate DC voltage sources. The proposed control algorithms provide synchronous symmetrical control of the motor phase voltage, together with elimination of the common-mode voltages in the systems, during the whole control range including the zone of overmodulation. Spectra of the phase voltage of motor drives with synchronized PWM do not contain even harmonics and sub-harmonics (combined harmonics), which is especially important for the systems with increased power rating. Simulations give the behavior of basic versions of synchronized PWM in these systems