METHOD OF ASYNCHRONOUS CONTROL FOR FOUR-QUADRANT CONVERTER Russian patent published in 2012 - IPC H02M1/12 H02M5/452 H02M7/539 H02M7/5395 H02P27/08 

FIELD: electricity.

SUBSTANCE: method of asynchronous control for four-quadrant converter is implemented by asynchronous sine pulse-width modulation with shift of clock and modulating signals in reference to main voltage phase. Switching of converter power keys is made at instant of time determined by ratio of modulation voltage and sweep voltage of sawtooth voltage generator on the basis of logic functions. Control pulses are generated by means of clock signal comparison with pre-set modulating sine signal variable in frequency and amplitude: sign of modulating signal is changed to the opposite one twice for instants of time corresponding to points of output voltage natural commutation. In compared channel high level of pulse-width modulated signal is generated if clock signal is less than pre-set signal or low level of pulse-width modulated signal is generated if clock signal is more than pre-set signal. In output channel two coupled output control signals are generated with inversion to each other from the first and second converter arms and simultaneously with commutation of modulating signals output signals are inverted in reference to pulse-width modulated signals in compared channel. Sawtooth signal is used as a clock signal. While generating control signals for converter keys clock signal is shifted in phase in reference to mains voltage transition through zero. Value of clock signal angle of shift is equal to value of modulating signal phase. Thus, phase shift of modulating signal in reference to mains voltage is asynchronous in regulation process.

EFFECT: generation of line current waveform of improved shape, close to sine wave, which contributes to increase of power factor and efficiency factor of four-quadrant converter due to form factor of input current within the whole range of loads.

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