"Hybrid matrix converters can potentially enable matrix converters in high power applications that conventional matrix converters will not be able to attain. It uses a conventional nine-switch matrix converter in conjunction with an auxiliary back-to-back ac-dc-ac converter that conditions the current and voltage waveforms on the input and output side of the matrix converter. The matrix converter processes the main power at low switching frequency to enable significant reduction of switching losses and to allow for adoption of high-power semiconductor devices such as integrated gate commutated thyristors (IGCTs). The auxiliary ac-dc-ac converter is dedicated to improving the power quality at the input and output terminals of the matrix converter by minimizing harmonic currents drawn from the source and harmonic voltages applied to the load. Essentially, the auxiliary back-to-back converter functions as a shunt-and-series active filter (AF). Several AF control techniques have been presented in the literature. Based on the operating principle, these techniques can be categorized into two groups. The first group of methods are based on instantaneous reactive power theory (IRPT) and extract the reactive component of the power and the oscillatory component of the real power. The other methods are based on filtering techniques and extract the fundamental component of the current or voltage such as notch filter and fast Fourier transform (FFT) methods. The main limitation for IRPT based method lies in its ineffectiveness when the harmonics are concurrently present in voltage and current while the limitation for FFT based method is its inability to compensate the fundamental component. To address these limitations of the aforementioned methods, a new control strategy based on power averaging has been proposed. This proposed control method is able to effectively obtain the correct active component of current or voltage in cases where both the current and the voltage are non-sinusoidal and provide full control over the power factor."--Pages ii-iii.
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