Guy Bingen

A novel approach to the generation and optimization of three-level PWM wave forms for induction motor inverters

The application of three-level pulsewidth modulation (PWM) to voltage source inverters feeding three-phase induction motors is considered. A subharmonic modulation method using two modulating waves is introduced. It is particularly well adapted to the elimination of specific harmonic bands. Systematic optimization of precalculated waveforms with respect to loss factor, shows that three-level PWM is very well suited to harmonic reduction. Transient behavior is discussed. It is concluded that three-level PWM yields significant improvements compared with two-level PWM, especially in high-power (gate-turn-off) GTO applications where the high DC link voltage requires a series connection of the switches.<<ETX>>

Computer-aided choice of digital PWM strategies

The goal of this study is to define the optimal PWM strategy adapted to a given variable-speed induction motor drive. A complete set of simulation programs performs steady-state and transient analysis of wave-forms. Some original PWM modes have been implemented on two digital modulators.

MODADEC: a VLSI circuit adapted to any kind of 2 levels PWM modulation

A new VLSI circuit which was developed to drive inverter-fed AC motors is described. It has been conceived as a peripheral of a microprocessor and offers a wide choice of PWM modes and strategies. The steady-state PWM waveforms are generated with high precision on the instant of commutation. The IC has high-frequency performances and can handle different optimizations of transients when changing PWM modes. The circuit is suitable for variable-speed applications, from servo-applications where a high commutation frequency and fast dynamic are required to high-power traction applications, where it is imperative to have smooth transitions and perfect torque control.<<ETX>>