Commutation failure is a common fault for line-commutated converters in the inverter. To reduce the possibility of commutation failure, many prediction algorithms based on alternating current (AC) voltage detection have already been implemented in high voltage direct current (HVDC) control and protection systems. Nevertheless, there are currently no effective methods to prevent commutation fail...

We discuss the theory of certain partially ordered sets that capture the structure of commutation classes of words in monoids. As a first application, it follows readily that counting words in commutation classes is #P-complete. We then apply the partially ordered sets to Coxeter groups. Some results are a proof that enumerating the reduced words of elements of Coxeter groups is #P-complete, a ...

For fixed object X in a monoidal category, an X-commutation structure on an object A is just a map X⊗A → A⊗X. We study aspects of such structures in case A has a dual object. We consider a monoidal category V,⊗, I; for simplicity we let it be strict (the application we have in mind is anyway a category of endofuncors on a category, with composition as ⊗). Let X be an object in V, fixed througho...

Matrix Converter is a near ideal static frequency changer which provides solution to the problem of converting ac from one frequency and one magnitude to variable frequency and variable magnitude ac, without any bulky energy storing components like capacitors or inductors. One of the major obstacles towards commercial acceptance of this topology has been the commutation of the bidirectional swi...

This paper presents the method of reducing torque ripple of brushless DC (BLDC) motor. The commutation torque ripple is reduced by control of the DC link voltage during the commutation time. The magnitude of voltage and commutation time is estimated by a neural network and optimized with an optimization method named particle swarm optimization (PSO) algorithm analysis. The goal of optimization ...

The closure of a regular language under a [partial, semi-] commutation I has been extensively studied. We present new advances on two problems of this area: (1) When is the closure of a regular language under [partial, semi-] commutation still regular? (2) Are there any robust classes of languages closed under [partial, semi-] commutation? We show that the class Pol(G) of polynomials of group l...

• Three-phase sine waves 192 steps per electrical revolution 10-bit amplitude resolution • Hardware dead-time generation • Controlled by hall-sensors • Speed control through run-time scaling of sine wave amplitude Speed reference from analog input • Automatically synchronizes to a running motor at startup • Safe startup using block-commutation the first commutation steps • Direction controlled ...

For the safe and fast recovery of line commutated converter based high-voltage direct current (LCC-HVDC) transmission systems after faults, a DC order optimization strategy is proposed. Considering constraint electric control quantities, with maximum active power transfer calculated by Thevenin equivalent parameters (TEPs) quasi-state equations LCC-HVDC systems. Meanwhile, to mitigate subsequen...

We define many new examples of modules of equations for secant varieties of Segre varieties that generalize Strassen’s commutation equations [7]. Our modules of equations are obtained by constructing subspaces of matrices from tensors that satisfy various commutation properties.