Class-D amplifier

The present invention relates to a closed loop class-D amplifier. The amplifier comprises a feedback arrangement with a low frequency path and a high frequency path. The high frequency path is used to obtain a self-oscillating condition in the amplifier and may contain passive components. The low frequency path comprises a low pass filter and a waveform correction circuit that reduces the amplifier distortion. Since the waveform correction circuit is applied in a low frequency path, the waveform correction unit may be realized using e.g. operational amplifiers that need not be rated for high frequencies. This allows a class-D amplifier to be realized with improved distortion and at a low cost

A bidirectional power converter

A three-phase power converter for converting power between a power grid network and a battery (255) comprises a three-phase grid transformer (230), a three-phase switching converter (251) for coupling to a positive terminal of the battery, a first, second and third series inductors(Ls1, Ls2, Ls3) coupled between the three-phase grid transformer and the three-phase switching converter, a control circuit (262) configured for controlling a first, second and third phase differences between first, second and third time-periodical power grid voltage signals(Vs1, Vs, Vs3) provided by the grid transformer and first, second and third converter time-periodical voltage signals (Vc1, Vc2, Vc3)provided to the switching converter such that the first, second and third time- periodical power grid voltage signals(Vs1, Vs2, Vs3) and first, second and third converter time-periodical currents(Ic1, Ic2, Ic3) are in phase. The three-phase grid transformer provides electrical isolation between the power grid network and the batter

Optimization of Combined Thermal and Electrical Behavior of Power Converters Using Multi-Objective Genetic Algorithms

A practical example of power electronic converter synthesis is presented, where a multi-objective genetic algorithm, namely non-dominated sorting genetic algorithm (NSGA-II) is used. The optimization algorithm takes an experimentally-derived thermal model for the converter into account. Experimental results are provided for verification