Highly dynamic "Dead time" compensation in electric drives based on signal adaptation

The article discusses the analysis and synthesis of a system of highly dynamic "dead time" compensation in the current loop of motors powered from transistor pulse-width converters. The first part of the paper provides a brief analysis of existing technical solutions, whose algorithms do not imply changes or additions to the power part of the drive and therefore are implemented exclusively by software. It is shown that the most modern methods of adaptive compensation can be considered using reference models of the control object. A non-search adaptive dead-time compensation system is proposed in the paper which provides signal self-tuning in the motor current loop, and dead-time compensation is based not on linearization or correction of nonlinear effects and delays of a pulse-width converter, but on parrying disturbing influences caused by the negative effects of “dead time”. Particular attention is paid to the practical orientation of the proposed solution; therefore, the considered algorithm is based solely on the basic principles of the control theory proven by practice. This approach allows us to ensure not only the transparency of the theoretical arguments presented in the article, but also reduce the time spent on the analysis and synthesis of the current loop, the purpose of which, ultimately, is the optimization of high-precision drives. With the absence of iteration methods of mathematics, the resources of microprocessor control units are minimized, which makes this method even more attractive in low-budget drives that do not claim to "exclusivity of integrated circuitry. The proposed algorithm was integrated into the existing current loop of an asynchronous electric drive with vector control, which proved the high efficiency of static and dynamic compensation of not only the “dead time” of the converter, but also of the non-linear effects associated with it that are difficult to analyze. The adaptive "dead time" compensation increased the efficiency of the electric drive at low motor speeds, compared to voltage boost compensation, by approximately four percent, and also reduced the motor torque ripple by about seventeen percent. An oscillogram of the phase current of a real drive with "dead time" compensation is given according to the principle of parametric voltage addition, which is the most common in practice, as well as a waveform of current with adaptive compensation action according to the principle considered in this article.