A CURRENT-TYPE PWM RECTIFIER WITH ACTIVE DAMPING FUNCTION

A new control method for current-type pulse-width modulation (PWM) rec tifiers which can provide active damping function is presented, This d amping function is effective only on the harmonic components of ac inp ut current selectively, Thus steady-state waveform distortion and tran sient oscillation of the input current are reduced by the active dampi ng effects, The active damping function can be realized by feedback co ntrol of an LC filter connected to the ac side of the rectifier, and i t does not require any additional components in the main circuits, per mitting a simple circuit configuration, The control system of the prop osed PWM rectifier is analyzed by using a simple block diagram develop ed in the present paper, From the analytical results, the influence of the circuit parameters and control delay on the active damping effect s and the stability of the operation are clarified to establish the de sign method, To confirm the effectiveness of the active damping functi on, some results of basic experiments are included, As an example of a pplication of the active damping function, the proposed rectifier is a pplied to reduce the harmonic currents generated by conventional recti fiers operating in parallel with the proposed rectifier, Some experime ntal results in this application are also included.