Input Displacement Power Factor Research Articles

Minimisation of AC Grid Side Input Power Factor Angle for Three-phase AC to Three-phase AC Matrix Converter under Varying Load

Abstract Minimisation of AC grid side input power factor angle for a ‘matrix converter (MC)’ improves the efficiency of the grid. Input volt-ampere requirement is minimum if the current drawn by the ‘MC’ is sinusoidal and input displacement power factor (IDPF) is unity. A MC is inherently capable of maintaining a unity displacement power factor (UDPF) angle at its input terminals. However, the input currents drawn from the grid are not sinusoidal. The high-frequency ripples are suppressed by input current filters (ICFs).These filters additionally introduce a leading phase angle for the current which varies with the loading. This phase lead can be compensated by adjusting the angle between the input current space vector and the input voltage space vector of the MC. The computation of this adjustment angle depends on the estimation of power losses in the switching devices. A simple method is proposed in this paper to estimate the switching losses without measuring device voltages and currents using the perturbation technique. The perturbation logic depends on input current, instantaneous active and reactive power computed at regular intervals of time. The proposed method effectively minimises the IDPF angle very close to zero. The experimental results are included for validation,

Current Control for an Indirect Matrix Converter With Filter Resonance Mitigation

A predictive control scheme for the indirect matrix converter including a method to mitigate the resonance effect of the input filter is presented. A discrete-time model of the converter, the input filter, and the load is used to predict the behavior of the instantaneous input reactive power and the output currents for each valid switching state. The control scheme selects the state that minimizes the value of a cost function in order to generate input currents with unity power factor and output currents with a low error with respect to a reference. The active damping method is based on a virtual harmonic resistor which damps the filter resonance. This paper shows experimental results to demonstrate that the proposed control method can generate good tracking of the output-current references, achieve unity input displacement power factor, and reduce the input-current distortion caused by the input filter resonance.

Predictive Current Control With Input Filter Resonance Mitigation for a Direct Matrix Converter

This paper presents a control method for direct matrix converters that combines the advantages of predictive control with active damping. The active damping is used to suppress the resonance of the input filter. A discrete-time model of the converter, the input filter, and the load parameters are used to predict the behavior of the input reactive power on the supply side and the output currents for each valid switching state. The control method selects the best commutation state, according to an optimizing algorithm and a cost function, in order to generate unity input displacement power factor with high-quality waveforms. The active damping method is based on a virtual harmonic resistor that damps the filter resonance. This paper shows simulated and experimental results to demonstrate that the proposed control method can generate good tracking of the output current references, achieve unity input displacement power factor, and reduce the input current distortion caused by the input filter resonance.

AC/AC power conversion based on matrix converter topology with unidirectional switches

In this paper, a new type of AC/AC power converter is proposed. The proposed converter is capable of direct AC/AC power conversion and, except for a few small snubber elements, it does not require the use of any input inductors or a DC-link capacitor. In contrast to the matrix converter, which requires bidirectional switches, the proposed converter consists of only unidirectional switches such as insulated gate bipolar transistors. The converter has a unity input displacement power factor, and its input line current waveform is similar to that of a diode rectifier with a DC-link inductor. The proposed converter has been validated experimentally using an induction motor driven with field-oriented control.